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HomeMy WebLinkAboutAPPROVED_RSD16_TIR_220304_v3 Renton Elementary School #16 Technical Information Report March 4, 2022 The information contained in this report was prepared by and under the direct supervision of the undersigned: Owner: Renton School District 300 SW 7th St Renton, WA 98057 (425) 204-2300 Contact: Traci Brewer-Rogstad Prepared for: Laurie Pfarr, P.E. LPD Engineering, PLLC 1932 1st Ave, Suite 201 Seattle, WA 98101 (206) 725-1211 Renton School District 300 SW 7th St Renton, WA 98057 (425) 204-2300 Contact: Traci Brewer-Rogstad SURFACE WATER UTILITY JFarah 04/11/2022 DEVELOPMENT ENGINEERING msippo 04/14/2022 RENTON ELEMENTARY SCHOOL #16 TECHNICAL INFORMATION REPORT TABLE OF CONTENTS Section 1 – Project Overview .................................................................................................................................. 1 Section 2 – Conditions and Requirements Summary ........................................................................................ 3 Section 3 – Offsite Analysis ...................................................................................................................................... 6 Section 4 – Flow Control and Water Quality Facility Analysis and Design ................................................ 9 Section 5 – Conveyance Systems Analysis and Design ................................................................................... 17 Section 6 – Special Reports and Studies .............................................................................................................. 18 Section 7 – Other Permits ...................................................................................................................................... 18 Section 8 – CSWPPP Analysis and Design ......................................................................................................... 18 Section 9 – Bond Quantities, Facility Summaries, and Declaration of Covenant .................................... 18 Section 10 – Operations and Maintenance Manual .......................................................................................... 18 FIGURES Figure 1: TIR Worksheet Figure 2: Vicinity Map Figure 3: Existing Conditions Figure 4: Proposed Conditions Figure 4a: Fully Dispersed Areas Figure 5: Soils Map Figure 6: Downstream Drainage Map APPENDICES Appendix A – Design Drawings Appendix B – Design Calculations and Supporting Information Appendix C – Construction Stormwater Pollution Prevention Plan (SWPPP) Narrative Appendix D – Operations and Maintenance Manual Appendix E – Bond Quantities (submitted separately), Facility Summaries, and Declaration of Drainage Covenant Appendix F – Special Reports and Studies LPD Engineering PLLC Page 1 New Elementary School #16 Technical Information Report, March 4, 2022 NEW ELEMENTARY SCHOOL #16 TECHNICAL INFORMATION REPORT MARCH 4, 2022 SECTION 1 – PROJECT OVERVIEW This Technical Information Report (TIR) is for the construction of the new Elementary School #16 for the Renton School District. Refer to Figure 1 – TIR Worksheet for basic site information. The new Elementary School #16 will be constructed on eleven (11) tax lot parcels and two (2) right-of-way (ROW) parcels with a total area of 11.17 acres. The parcels are bounded by NE 12th Street and a neighboring church property to the north, Duvall Avenue NE to the east, and residential properties to the west and south. NE 10th Street is just beyond the project property to the south. The site is located in Section 10, Township 23 North, Range 5 East, Willamette Meridian. Refer to Figure 2 – Vicinity Map. The City of Renton has adopted the 2016 King County Surface Water Design Manual (KCSWDM) with the City’s 2017 Surface Water Design Manual amendment (RSWDM). According to Figure 1.1.2.A of the RSWDM, Flow Chart for Determining Type of Drainage Review Required, the project is subject to a “Full Drainage Review” because the project results in greater than 2,000 square feet (SF) of new plus replaced impervious surface, and it is not defined as a large project or single-family residential project. Per the “Full Drainage Review” requirements in Table 1.1.2.A, the TIR addresses Core Requirements #1-9 and Special Requirements #1-5 of the 2017 RSWDM. Existing Site The majority of the parcels contained in the project site previously contained single-family residences which were demolished in January of 2019 and the remaining parcels were undeveloped. See Figure 3 – Existing Conditions. There are two existing wetlands on the site. The City’s Critical Area Map do not identify wetlands on-site; however, a wetland delineation report was performed by The Watershed Company on November 2019 and initially identified three wetlands; Wetlands A, B, C. Further evaluation eliminated Wetland A because it did not meet the criteria for jurisdictional wetlands. Wetland B is located in the northeast portion of the site and Wetland C is along the west property line. The Wetland C, which provides a higher level of function than Wetland B, will be maintained as part of the school development. It is classified as a Type III and requires a 100-ft buffer. Wetland B is considered a Type IV and will be removed and mitigated through a wetland banking system as a part of this project. Topographically, the site sits at a high point relative to the surrounding properties. Generally, the site slopes down from the east to the west with elevations ranging from approximately 438 feet in the southeastern portion of the parcel to approximately 409 feet at the existing west wetland area. The site also has areas which slope from south to north, and a smaller area that slopes towards the LPD Engineering PLLC Page 2 New Elementary School #16 Technical Information Report, March 4, 2022 southwest. The existing topography divides the site drainage into three basins as described in detail below. The site is located within three drainage basins, denoted as the South Basin, the North Basin, and the Wetland Basin. The areas within the South Basin sheet flow to the southwest. The runoff is collected by the existing catch basins along the east side of Chelan Avenue NE and flows into a 12-inch main. The North Basin discharges into Wetland B which flows offsite to the north via a 12-inch storm line and ultimately discharges into a 12-inch storm pipe within NE 12th Street. The Wetland Basin sheet flows to Wetland C and discharges from the site via a 15-inch CMP that conveys flow to the north and eventually connects into a 15-inch storm pipe within NE 12th Street. The storm system from Chelan Avenue NE and NE 12th Street eventually converge and ultimately discharge to May Creek which outlets to Lake Washington. A subsurface exploration and geotechnical feasibility study were conducted by Associated Earth Sciences, Inc. (AESI). They prepared their findings in a report dated November 23, 2020. Their field study included fourteen exploration borings across the site. The explorations typically encountered existing fill and recessional outwash sediments underlain by dense, silty Vashon lodgement till sediments. Five exploration borings encountered surficial existing fill to thicknesses of up to approximately 7 feet. Two explorations found shallow Vashon recessional outwash sediments ranging in thickness from approximately 2.5 to 5 feet thick. The northernmost exploration borings terminated in potential lodgement till and advance outwash transition sediments at depths of approximately 20.5 to 21.5 feet. Groundwater was not encountered in any of the explorations completed for this study at the time of exploration. According to AESI’s exploration, the use of potential stormwater infiltration was found to be infeasible due to the extent of dense, silty soils across the site. The existing fill is not a suitable infiltration receptor due to its variable density, silt, and organic content. The recessional outwash found in two of the borings do not have enough vertical depth to support infiltration without adequate separation from the hydraulically restrictive layers. Lodgement till is not a suitable infiltration receptor due to its high silt content. Proposed Site Improvements The project is not considered a redevelopment project based upon the following definition from the KCSWDM: “Redevelopment project means a project that proposes to add, replace, or modify impervious surfaces (for purposes other than a residential subdivision or maintenance) on a site that is already substantially developed in a manner consistent with its current zoning or with a legal non- conforming use, or has an existing impervious surface coverage of 35% or more.” The survey was used in AutoCAD to delineate the existing impervious coverage for the project property. Refer to Figure 3 – Existing Conditions. The existing impervious coverage is less than 35% and therefore the project is considered a New Development. The new Renton Elementary School #16 will include an approximately 46,000 square foot school building with a central outdoor courtyard, natural grass playfield, hard and soft surface play areas, an entry plaza, emergency and fire apparatus access loop, a designated bus loop, parking, and a student loading lane. Refer to Figure 4 – Proposed Conditions. LPD Engineering PLLC Page 3 New Elementary School #16 Technical Information Report, March 4, 2022 Improvements will be made to the frontage along Duvall Avenue NE to accommodate the three proposed driveways, as well as the two driveways on the neighboring property to the north, along with a sidewalk, planter strip, and bicycle/vehicle queuing lane per coordination with the City of Renton. Additionally, Chelan Avenue NE will also be improved to establish a new egress only driveway, with an extension of the existing sidewalk and planter strip to the north through the School District property. The project proposes approximately 230,530 SF (5.29 acres) of new plus replaced impervious surface. In order to preserve the drainage patterns of the existing site, the post-developed grading of the project site has been designed to maintain the existing basin areas, to the extent feasible, which have the same denotation of South Basin, North Basin, and Wetland Basin. For the South Basin, stormwater runoff will be collected in a series of catch basins and routed via pipe conveyance systems to a shallow flow control detention facility. This is currently designed as an ADS StormTech Chamber system, located on the south portion of the site beneath the proposed parking lot. The detention system will have a flow control structure to attenuate flows and will be followed by a water quality treatment facility which is designed as a Modular Wetland vault. The detained and treated discharge will eventually be conveyed to the existing 12-inch main within Chelan Avenue NE. For the North Basin, stormwater runoff will be collected in a series of catch basins and routed via pipe conveyance systems to an ADS StormTech Chamber system, located underneath the play field. Under- drain pipes within the play field subsurface will also discharge into the StormTech system. The detention system will have a flow control structure to attenuate flows and will be followed by a water quality treatment facility which is designed as a Modular Wetland vault. The detained and treated discharge will then discharge into an existing vegetated swale running along the east side of the gravel drive perpendicular to NE 12th Street, before entering the piped conveyance system in the right-of-way. In the Wetland Basin, the project proposes to utilize full dispersion for the majority of the new plus replaced impervious surfaces in this basin which includes a portion of the roof, fire lane, and pedestrian walkways. Runoff from the roof and paved surfaces will be routed to gravel dispersion trenches and overflow into the vegetated wetland buffer zone, eventually discharging into Wetland C. Proposed surfaces that utilize full dispersion are not considered to be target surfaces and thus, do not trigger flow control and water quality requirements. On-site Best Management Practices (BMPs) have been evaluated. As stated above, the geotechnical investigation by AESI did not find the site’s soil profile favorable for infiltration. The stormwater strategy will be to utilize Dispersion BMPs as well as a permeable pavement type system for the fire lane within the Wetland Basin. Site constraints do not allow for BMPs to be used for the South and North Basins. Refer to Section 4 – Flow Control and Water Quality Analysis and Design for further information on the storm drainage design. SECTION 2 – CONDITIONS AND REQUIREMENTS SUMMARY This section addresses the requirements set forth by the 2017 Renton SWDM, Core and Special Requirements listed in Chapter 1. LPD Engineering PLLC Page 4 New Elementary School #16 Technical Information Report, March 4, 2022 Core Requirements Core Requirement 1 – Discharge at Natural Location (1.2.1): The proposed conditions will maintain the existing discharge locations to the maximum extent feasible. The site is divided into three drainage basins, the South Basin, the North Basin, and the Wetland Basin. Flow control detention facilities and BMPs will be implemented, thus attenuating discharge from the project area and creating no adverse impacts on the downstream system. Refer to the Offsite Analysis section of this report for a description of the existing discharge points from the site. Core Requirement 2 – Off-site Analysis (1.2.2): A Level 1 Downstream Analysis will be included in the TIR that is provided with the Building Permit Submittal. Core Requirement 3 – Flow Control (1.2.3): Per the City of Renton Flow Control Application Map, Reference 15-A in the RSWDMA, the project site is located within Flow Control Duration Standard area. Therefore, the flow duration of predeveloped rates for forested (historical) site conditions over the range of flows extending from 50% of 2-year up to the full 50- year flow AND matches peaks for the 2- and 10-year return periods. Per the RSWDMA, flow control facilities must mitigate the runoff from the target surfaces which include new impervious surfaces and new pervious surfaces not fully dispersed. For further information regarding the flow control design, refer to Section 4 of this report. Core Requirement 4 – Conveyance System (1.2.4): Refer to Section 5 of this report for conveyance analysis. Core Requirement 5 – Erosion and Sedimentation Control (1.2.5): A Temporary Erosion and Sediment Control (TESC) plan has been included with the plan set. The TESC plan will be considered the minimum for anticipated site conditions. The Contractor will be responsible for implementing all TESC measures and upgrading as necessary. The TESC facilities will be in place prior to any demolition, clearing, grubbing or construction. Core Requirement 6 – Maintenance and Operations (1.2.6): The Operations and Maintenance Manual for the project is in Appendix D. Core Requirement 7 – Financial Guarantees and Liability (1.2.7): Financial guarantees and liability are not anticipated to be required since the Owner is a public agency. Core Requirement 8 – Water Quality (1.2.8): The project proposes more than 5,000 square feet of pollution-generating impervious surface (PGIS), and therefore this project will require water quality treatment. Per the City of Renton WQ Applications Map, the project is in a Basic Water Quality Treatment area; however, since schools are classified as commercial projects, Enhanced Basic Water Quality is required. For further information regarding the water quality design requirements, refer to Section 4 of this report. Core Requirement 9 – On-Site BMPs (1.2.9): The project site proposed more than 2,000 SF of new plus replaced impervious surfaces which will require an evaluation of BMP feasibility for all target surfaces. Per section 1.2.9.2 of the 2017 RSWDMA, this project will be subject to Large Lot BMP LPD Engineering PLLC Page 5 New Elementary School #16 Technical Information Report, March 4, 2022 Requirements since the project site is larger than 22,000 SF. Refer to the On-Site BMPs evaluation within Section 4 of this report. Special Requirements Special Requirement 1 – Other Adopted Area-Specific Requirements (1.3.1): The City of Renton Surface Water Design Manual is one of several adopted regulations in the City of Renton that apply requirements for controlling drainage on an area-specific basis. Other adopted area-specific regulations include requirements that have a more direct bearing on the drainage design of a proposed project. These regulations include the following: • Master Drainage Plans (MDPs) – The project is not within an area covered by an approved Master Drainage Plan. Project is not a Master Planned Development, a Planned Unit Development, a subdivision that will have more than 100 lots, a commercial development that will construct more than 50 acres of impervious surface, and will not clear more than 500 acres within a drainage sub-basin. Therefore, a Master Drainage Plan is not required. • Basin Plans (BPs) – The Watershed Management Committee Lower Cedar River Basin and Nonpoint Pollution Action Plan, adopted 1997, was reviewed to determine if there are regulations applicable to this site. There are no additional water quality requirements listed by the report. • Salmon Conservation Plans (SCPs) – The project is not within an area governed by SCPs. • Lake Management Plans (LMPs) – The project is not within an area governed by an LMP. • Hazard Mitigation Plan – The proposed project is not within an area with a Hazard Mitigation Plan. • Shared Facility Drainage Plans (SFDPs) – The proposed project is not within an area with an SFDP. Special Requirement 2 – Flood Hazard Area Delineation (1.3.2): According to King County iMap, the project does not contain nor is it adjacent to a Flood Hazard Area. Special Requirement 3 – Flood Protection Facilities (1.3.3): The project does not have existing flood protection facilities, nor does it propose new flood protection facilities. Special Requirement 4 – Source Control (1.3.4): In the proposed conditions, kitchen facilities will involve activity A-8 listed within the 2016 King County Stormwater Pollution Prevention Manual (KCSPPM) that will require the use of source control measures. Activity A-8 includes storage of solid and food wastes (including cooking grease). Therefore, a grease interceptor will be required as a source control measure. Special Requirement 5 – Oil Control (1.3.5): The project will not have high-use site characteristics nor is it an existing high-use site; therefore, oil control is not required. Special Requirement 6 – Aquifer Protection Area (1.3.6): The project is not located within an aquifer protection area. LPD Engineering PLLC Page 6 New Elementary School #16 Technical Information Report, March 4, 2022 SECTION 3 – OFFSITE ANALYSIS The following is the Level 1 downstream analysis for the proposed project. Refer to Figures 6A and 6B - Downstream Drainage Map. The following resources have been reviewed for the project area: Task 1 – Study Area Definition and Maps The school property incorporates eleven parcels (#1023059173, #1023059275, #1023059096, #1023059107, #1023059249, #1023059138, #1023059124, #1023059076, #1023059202, #1023059332, #1023059139), as well as two unopened ROW parcels, totaling approximately 11.17 acres. The downstream analysis for the project area is based upon the following resources: • Site Survey • On-site Investigation • King County iMap • City of Renton GIS Mapping • A subsurface exploration and geotechnical feasibility study prepared by Associated Earth Sciences, Inc.; dated November 23, 2020 Task 2 – Resource Review Basin Summary According to the site survey and GIS mapping, the project is situated within three drainage basins, denoted as the South Basin, the North Basin, and the Wetland Basin. The North Basin and Wetland basin converge along NE 12th Street prior to the ¼-mile mark. The South basin eventually converges with the North and Wetland Basin which discharges to May Creek and ultimately outlets to Lake Washington. Refer to Figure 3 – Existing Conditions, for a layout of the existing basin dividing line. Floodway Map The site is not located within a Floodway or Floodplain per the Washington State Department of Ecology Flood Maps and King County iMap. Sensitive Areas The following is a summary of SAO sensitive areas located within the project area or within the downstream drainage course from the project area. The King County iMap application was used to examine the SAOs.  SAO Erosion Hazard – The project site is not located within an erosion hazard area.  SAO Seismic Hazard – The project site is not located within a seismic hazard area.  SAO Landslide Hazard – There are no landslide hazard areas located within the project site.  SAO Coal Mine – There are no coal mines located within the project site.  SAO Stream – According to King County iMap, there are no unclassified stream or any waterbodies through the developed school site.  SAO Wetland – There are is a wetland located within one mile downstream of the project site. LPD Engineering PLLC Page 7 New Elementary School #16 Technical Information Report, March 4, 2022  Groundwater Contamination – According to iMap, the project site has no mapped susceptibility to groundwater contamination.  Sole Source Aquifer – Per King County iMap, the project site is not located within a sole source aquifer area.  Critical Aquifer Recharge Area – The project site is not considered a Critical Aquifer Recharge Area.  Channel Migration Hazard – Per King County iMap, the project site is not located within a channel migration hazard zone. Topographic Map The detailed topographic information for the project area is shown on the design drawings. Drainage Complaints According to King County’s iMap program, there have been no drainage complaints within the last 10 years within the project site, upstream area, or downstream area. Soils Survey A published geologic map of the project, Geologic Map of Surficial Deposits in the Seattle 30’ by 60’ Quadrangle, Washington, by J.C. Yount, J.P. Minard, and G.R. Dembroff, indicates that the site is underlain at shallow depths by Vashon lodgement till. The generally consistent with geotechnical engineer’s investigation. Refer to Section 1 of this report and Figure 5: Soils Map for additional soils information. Migrating River Studies According to King County’s iMap program, the project site is not located within or adjacent to a channel migration hazard area. Water Quality Problems Per the 2017 Renton SWDM, King County-identified water quality problems do not apply to the City. Task 3 – Field Inspection A field inspection and Level 1 Downstream analysis was conducted by LPD on April 23rd, 2021 to verify the on-site conditions, downstream drainage paths, and upstream basins. The weather during the site investigation was clear and sunny, with a temperature of approximately 53 degrees Fahrenheit. Refer to Drainage System Description and Problem Descriptions below for information about the existing conditions and downstream analysis. Task 4 – Drainage System Description and Problem Descriptions As stated previously, the project is situated within three drainage basins, denoted as the South Basin, the North Basin, and the Wetland Basin. Below is a description of each downstream drainage from the project area to a distance of approximately one-quarter mile downstream. Refer to Figure 6A and 6B – Downstream Drainage Map for details. South Basin LPD Engineering PLLC Page 8 New Elementary School #16 Technical Information Report, March 4, 2022 A small portion of stormwater runoff from the south appears to sheet flow toward the south through a vegetated area on the property. Below is a description of the downstream drainage course from this point: 1. Runoff sheet flows across the site to the south to the existing storm infrastructure within Chelan Avenue NE. Runoff flowing into Chelan Avenue NE is collected by an existing catch basin along the east side of the road. The catch basin outlets to the west via a 12-inch pipe for approximately 30 linear feet and connects to the 12-inch storm main running along the west side of the road. 2. Runoff then heads south via the 12-inch public storm main for approximately 170 linear feet prior to connecting to a 60-inch private detention pipe system on the north side of 10th Avenue NE. The detention system outlets via a 12-inch pipe that runs across 10th Avenue NE for approximately 21 linear feet to the 12-inch storm main within 10th Avenue NE. 3. The runoff in 12-inch storm main within 10th Avenue NE runs west for approximately 80 linear feet and then is directed north via a 12-inch pipe and discharges to a detention pond maintained by the City. 4. The detention pond overflows to an 18-inch pipe that directs flow south to the 18-inch public storm main within 10th Avenue NE. 5. Runoff then continues west for approximately 200 feet until it reaches a storm drain manhole at the intersection of NE 10th Street and Anacortes Avenue NE. 6. Flow is then directed north via a 30-inch main within Anacortes Avenue NE for approximately 700 feet, passing the ¼-mile mark downstream of the project site. 7. The 30-inch main system continue northwest for another ¼-mile prior to crossing NE Sunset Blvd. Stormwater flows northwest across the intersection of NE Sunset Blvd. and Union Avenue NE to an unnamed creek. From here, the unnamed creek eventually discharges to May Creek which outlets to Lake Washington. North Basin The North Basin contains the majority of the project site improvements. On-site stormwater runoff from the east portion of the site appears to sheet flow toward the existing Wetland B. Wetland B is proposed to be filled in the developed conditions. Below is a description of the downstream drainage course from this point: 1. Wetland B discharges north to an 8-inch culvert and flows for approximately 125-feet until it reaches an existing catch basin located on the adjacent neighboring church property. 2. The runoff then flows west from the catch basin for approximately 130 linear feet and outlets to a vegetative drainage ditch along the drive access easement for the school property that is off of NE 12th Street. 3. The drainage ditch flows north for approximately 50 linear feet and is collected by a 12-inch concrete culvert. 4. The 12-inch concrete culvert runs north for approximately 50 linear feet, crossing NE 12th Street to an existing catch basin located on the north side of the street. 5. Flow is then directed west via a 12-inch storm main for approximately 450 linear feet to a catch basin that collects flow from Wetland C. Wetland Basin On-site stormwater runoff from the west portion of the site appears to sheet flow toward the existing Wetland C. Wetland C is proposed to be protected and maintained in the developed conditions. Below is a description of the downstream drainage course from this point: LPD Engineering PLLC Page 9 New Elementary School #16 Technical Information Report, March 4, 2022 6. Wetland C discharges to the north to a 15-inch corrugated metal culvert that runs through a neighboring multi-family residential property for approximately 200 linear feet to the northwest corner of the neighboring property. 7. Flow is then collected by a 15-inch concrete culvert for approximately 60 linear feet running north across NE 12th street. The flow is collected by an existing catch basin that collects flow from the existing Wetland B as described above. 8. Flow from this catch basin continues west via a 15-inch storm main for approximately 75 linear feet to the intersection of NE 12th Street and Anacortes Avenue NE. 9. From the intersection, runoff is directed north via a 15-inch storm main along Anacortes Avenue NE. 10. The 15-inch main discharges to a 72-inch by 44-inch corrugated metal arched pipe that flows northeast across a commercial parking lot for approximately 760-feet, passing the ¼-mile mark downstream of the project site. 11. The corrugated metal arched pipe transitions to a 48-inch concrete culvert which then crosses Duvall Avenue NE and discharges to an unnamed creek flow northeast. 12. From here, the unnamed creek eventually discharges to May Creek which outlets to Lake Washington. Task 5 – Mitigation of Existing or Potential Problems During the field investigation there were no signs of erosion or overtopping of the downstream drainage system. At this time, the existing downstream drainage course appears to have adequate capacity to convey the proposed flows from the project. SECTION 4 –LOW IMPACT DEVELOPMENT (LID), FLOW CONTROL AND WATER QUALITY FACILITY ANALYSIS AND DESIGN Existing Site Hydrology Please refer to Section 1- Project Overview and Section 3- Off-site Analysis of this report for a description of the existing hydrology. Developed Site Hydrology Please refer to Section 1- Project Overview and the Flow Control System section below in this report for a description of the proposed hydrology. Performance Standards Please refer to Section 2- Conditions and Requirements Summary, and the On-Site BMPs, Flow Control System, and Water Quality sections of this report for a description of the required standards applicable to this report. Flow Control Facility Standard As stated previously, the project site is located within Flow Control Duration Standard area. Therefore, the flow duration of predeveloped rates for forested (historical) site conditions over the range of flows extending from 50% of 2-year up to the full 50- year flow AND matches peaks for the 2- and 10-year return periods. Per Section 1.2.3.1.B. of the 2017 RSWDMA, below is a description and evaluation of the target surfaces for this project: LPD Engineering PLLC Page 10 New Elementary School #16 Technical Information Report, March 4, 2022 1. New impervious surface that is not fully dispersed per the criteria on Section 1.2.3.2.C, as specified in Appendix C. For individual lots within residential subdivision projects, the extent of new impervious surface shall be assumed as specified in Chapter 3. Note, any new impervious surface such as a bridge or boardwalk that spans the ordinary high water of a stream, pond, or lake may be excluded as a target surface if the runoff from such span is conveyed to the ordinary high water area in accordance with Criteria (b), (c), (d), and (e) of the "Direct Discharge Exemption" (p 1-39) Interpretation: New impervious surfaces fully dispersed will not be considered a target surface. This would apply to the impervious surfaces within the North and South Basin. New impervious surfaces that cannot be fully dispersed are considered to be a target surface. For new impervious surfaces within the Wetland Basin, the project proposes to utilize full dispersion. Per the definitions above, the grass play field in the North Basin will be considered as a target surface as a new impervious surface. It should be noted, that the grass under-drained play field will be hydrologically modeled as 50% impervious and 50% grass in the areas where the grass filed is not lined. Since the detention facility underneath the grass field will have an EPDM liner on the bottom and sides of the facility to ensure that the stormwater discharge goes through the water quality treatment facility before leaving the site, the footprint of the detention underneath the grass field will be modeled as 100% impervious. 2. New pervious surface that is not fully dispersed or not farmland dispersed as specified in Appendix C. For individual lots within residential subdivision projects, the extent of new pervious surface shall be assumed to be the entire lot area, except the assumed impervious portion and any portion in which native conditions are preserved by covenant, tract, or easement. In addition, the new pervious surface on individual lots shall be assumed to be 100% grass. Interpretation: The definition of new pervious surface from the 2017 RSWDMA includes the conversion of a native vegetated surface or other native surface to non-native pervious surface (e.g. conversion of forest or meadow to pasture land, grass land, cultivated land, lawn, landscaping, bare soils, etc.), or any alteration of existing non-native pervious surface that significantly increases surface and storm water runoff (e.g., conversion of pasture land, grass land, or cultivated land to lawn, landscaping, or bare soil). The majority of the landscape improvements will be amended as lawn area which are in areas where the existing site was non- native lawn. 3. Replaced impervious surface that is not fully dispersed as specified in Appendix C on a non- redevelopment project in which the total of new plus replaced impervious surface is 5,000 square feet or more, OR new pervious surface is ¾ acre or more. Interpretation: Replaced impervious surfaces that are not fully dispersed will be considered target surfaces. 4. Replaced impervious surface that is not fully dispersed on a transportation redevelopment project in which new impervious surface is 5,000 square feet or more and totals 50% or more of the existing impervious surface within the project limits. LPD Engineering PLLC Page 11 New Elementary School #16 Technical Information Report, March 4, 2022 Interpretation: Since the project is not a transportation redevelopment project, this item does not apply to this project. 5. Replaced impervious surface that is not fully dispersed as specified in Appendix C, on a parcel redevelopment project in which the total of new plus replaced impervious surface is 5,000 square feet or more and whose valuation of proposed improvements (including interior improvements and excluding required mitigation improvements) exceeds 50% of the assessed value of the existing site improvements. Interpretation: Since the project is a new development, this item does not apply to this project. As determined above, new plus replaced impervious surfaces, and new pervious surfaces not fully dispersed are considered the “target surface” requiring flow control mitigation and BMPs. Water Quality Treatment Standards The treatment goal for facility options in the Enhanced Basic WQ Menu is to accomplish better removal of heavy metals and potentially other toxic materials than can be achieved by basic treatment, while still meeting the basic treatment goal of 80% TSS removal. The specific target performance is > 30% reduction of dissolved copper and > 60% removal of dissolved zinc. Similarly, to the Flow Control Standards section above, Section 1.2.8.1 of the 2017 RSWDMA states that pollution-generating new plus replaced impervious surfaces, and new pervious surfaces not fully dispersed are considered the “target surface” requiring water quality treatment. Conveyance System Capacity Standards The proposed conveyance systems will be designed to convey at a minimum the 25-year peak flow rate from the tributary developed area. On-Site BMPs Per Core Requirement #9, the project site proposed more than 2,000 SF of new plus replaced impervious surfaces which will require an evaluation of BMP feasibility for all target surfaces. Per section 1.2.9.2 of the 2017 RSWDMA, this project will be subject to Large Lot BMP Requirements since the project site is larger than 22,000 SF. For each drainage basin, the feasibility of on-site BMPs must be evaluated for each BMP listed in Section 1.2.9.2.2 of the RSWDMA. Due to the fill and glacial till found on the project site, there is no suitable stormwater infiltration receptor for infiltration BMPs. For these reasons, the LID performance standard cannot be achieved. Below is the alternate FCBMP list approach for the site and frontage improvements within all three drainage basins. North and South Basin BMP Evaluation: 1. Full Dispersion: Full dispersion of runoff from target surfaces is not feasible for both the site area and road frontage according to Section C.2.1.1 of the KCSWDM due to the limited native vegetated surface downstream of each of these areas on site. 2. Full Infiltration of Roof Runoff: Per the geotechnical report, the site soils consist of fill and lodgment till. Fill soils are not suitable as a stormwater infiltration receptor. The lodgment till is very dense and silty, and the infiltration potential of lodgment till is very low. Stormwater infiltration using lodgment till as the receptor horizon is not recommended by the Geotechnical Engineer. LPD Engineering PLLC Page 12 New Elementary School #16 Technical Information Report, March 4, 2022 3. Since the target impervious surfaces could not be mitigated by Requirements 1 and 2 above, the following has been reviewed and implemented where feasible: • Full Infiltration: Full infiltration of runoff from target surfaces is not feasible. As stated above: fill soils are not suitable as a stormwater infiltration receptor; and infiltration with lodgment till as the receptor horizon is not recommended by the Geotechnical Engineer. • Limited Infiltration: As stated above: fill soils are not suitable as a stormwater infiltration receptor; and infiltration with lodgment till as the receptor horizon is not recommended by the Geotechnical Engineer. Therefore, limited infiltration is considered infeasible. • Bioretention: Per Section C.2.6, a bioretention facility without underdrains is considered infeasible as stated above due to: fill soils are not suitable as a stormwater infiltration receptor; and infiltration with lodgment till as the receptor horizon is not recommended by the Geotechnical Engineer. Underdrains are not permitted by the City to meet Core Requirement #9. • Permeable Pavement: As stated above: fill soils are not suitable as a stormwater infiltration receptor; and infiltration with lodgment till as the receptor horizon is not recommended by the Geotechnical Engineer for this area. 4. Basic Dispersion: is not feasible to be used as BMP per Section C.2.4 of the RSWDMA due to the limited vegetative flow path downstream of the target surfaces. Wetland Basin BMP Evaluation 1. Full Dispersion: The project proposes to disperse approximately 19,750 SF of impervious surfaces by utilizing gravel dispersion trenches. A fully dispersed surface conforms to the BMP strategy detailed in Appendix C, Section C.2.1 of the RCSWDMA. The design criteria for full dispersion is further described in the Flow Control Analysis and Design section of this report. 4. Permeable Pavement: The fire lane on the west side of the proposed building is proposed as a grass-pave surface totaling 8,470 SF. This modular grid pavement system will have grass planted in the openings within the grid material. The increased water storage provided in the grid soil and base, and the increased evapotranspiration provided by the grass with attenuate runoff. The grass surface will also provide a more natural look for the fire lane, which will see limited use, adjacent to the wetland buffer. Because of the native till soils at the site, it is not anticipated that infiltration will occur through the grass-pave system, but any stormwater overflows from the grass-pave area will be dispersed via sheet flow into the edge of the wetland buffer. Flow Control Analysis and Design As previously mentioned, the project is required to meet the Level 2 Flow Control Duration standard, for which the project must match developed discharge durations to predeveloped durations for the range of predeveloped discharge rates from 50% of the 2-year peak flow up to the full 50-year peak flow and matches historic 2- and 10-year peaks. Per the RSWDMA, the predeveloped conditions must model the target surfaces as historic site conditions (forested) in order to reasonably anticipate development- induced problems. The majority of the site which includes the asphalt surfaces, concrete surfaces, and roof will be considered to be 100% impervious surfaces. The natural turf field will be considered as 50% impervious and 50% grass. The field with the detention facility footprint underneath will be considered 100% impervious. The grass landscape areas will be considered as 100% pervious surfaces. The grass- paved fire lane will be a grass modular grid pavement and will be considered as 100% pervious per the RSWDMA Table 1.2.3.A. Stormwater modeling was conducted using the MGSFlood Version 4, an approved continuous-modeling software by the RSWDMA. LPD Engineering PLLC Page 13 New Elementary School #16 Technical Information Report, March 4, 2022 The proposed project will be divided into three basins: South Basin, North Basin, and Wetland Basin. Refer to Figure 4 – Proposed Conditions for a clear delineation of drainage basins. South Basin South Basin Target Surfaces to Flow Control Facility The South Basin will have two detention facilities that consist of StormTech SC-740 arch chambers within a gravel basin, which will utilize both the storage within the chambers and also the void space within the gravel for stormwater detention. The StormTech chambers and gravel basin have a non- uniform change in storage volume as the stage height increases. To account for this, a stage storage spreadsheet was used to calculate the storage within the StormTech chambers and surrounding gravel material at an interval of stage heights. A copy of this spreadsheet is included in Appendix B. The minimum design standards for the SC-740 chamber require a 30-inch chamber, 6-inches gravel above and 6-inches gravel below the chamber. In order to account for the change in surface elevation in the south parking lot, as well as accommodate trees and light poles in the landscape planters, the detention system was divided into two separate facilities, Detention #1A and Detention #1B such that a portion of runoff could flow to an area with more live storage depth available. Around the perimeter of the chambers, a 12-inch gravel section will be used, although in some areas there will be extra gravel to accommodate bends, manifolds, and access structures. A separate flow control structure for each detention facility will be installed that will attenuate stormwater outflow and utilize the storage within the chambers and its surrounding permeable gravel basin. Detention #1A utilizes a live storage depth of 3-feet within the chamber section. Detention #1B utilizes a storage depth of 1.83-feet within the chamber section. The total required storage volume of the detention system was found to be 13,935 cubic feet. The designed StormTech Facility will have a slightly larger storage volume to accommodate any minor site changes during construction. A full summary of areas and MGSFlood Output for the South Basin can be found in Appendix B of this report. South Basin Bypass Target Surfaces For the South Basin, the project includes bypass areas from both on-site improvements and off-site improvements that cannot be gravity-drained to the detention facility. On-site runoff bypass areas include the driveway entry and associated walkways. Offsite runoff includes the sidewalk improvements within Chelan Avenue NE. The bypass area totals 2,335 SF of impervious surface. All criteria per Section 1.2.3.2.E of the 2017 RSWDM manual the following criteria have been met for the bypass area. The project proposes to waive the Item #5 requirement of Section 1.2.3.2.E using the following criteria: 1. The existing conditions 100-year peak discharge from the area of bypassed target surfaces is increased by no more than 0.15cfs for the 15-minute time step. MGSflood output for calculations of the bypass area have been provided in Appendix B. Below is a Table 1 summarizing the flow rate results: LPD Engineering PLLC Page 14 New Elementary School #16 Technical Information Report, March 4, 2022 Table 1 – Net Peak Flow Rates for Bypass Area of South Basin Peak Runoff Rates for Project Work Area Storm Event Existing Conditions Proposed Conditions Delta 100-yr 0.191 cfs 0.209 cfs 0.018 cfs 2. On-Site BMPs must be applied to bypass target surfaces per Appendix C. After applying the feasibility to each On-Site BMP to the bypass target surfaces, all BMPs were found to be infeasible. Refer to the On-Site BMP section of this report. North Basin North Basin Target Surfaces to Flow Control Facility The proposed StormTech detention facility will consist of MC-3500 chambers within a gravel basin, which will utilize both the storage within the chambers and also the void space within the gravel basin for stormwater detention. The StormTech chambers and gravel basin have a non-uniform change in storage volume as the stage height increases. To account for this, a stage storage spreadsheet was used to calculate the storage within the StormTech chambers and surrounding gravel material at an interval of stage heights. A copy of this spreadsheet is included in Appendix B. The minimum design standards for the MC-3500 chamber require a 45-inch chamber, 9-inches gravel below and 12-inches gravel above the chamber, which were the parameters used in this design. Around the perimeter of the chambers, a 12-inch gravel section will be used, although in some areas there will be extra gravel to accommodate bends, manifolds, and access structures. A flow control structure will be installed that will attenuate stormwater outflow and utilize the storage within the chambers and its surrounding permeable gravel basin. The required storage volume of the detention system was found to be 78,897 cubic feet, with a live storage depth of 4.75-feet. The designed StormTech Facility will have a slightly larger storage volume to accommodate any minor site changes prior to construction. A full summary of areas and MGSFlood Output for the South Basin can be found in Appendix B of this report. North Basin Bypass Target Surfaces For the North Basin, the project includes bypass areas from both on-site improvements and off-site improvements that cannot be gravity-drained to the detention facility. On-site runoff bypass area includes the three driveway approaches accessing Duvall Avenue NE as well as the gravel maintenance access to NE 12th Street. Offsite runoff includes the sidewalk improvements and queueing lane within Duvall Avenue NE as well as the driveway approaches into the neighboring property to the north. The bypass area totals 15,830 SF of impervious surface. All criteria per Section 1.2.3.2.E of the 2017 RSWDM manual the following criteria have been met for the bypass area. The project proposes to waive the Item #5 requirement of Section 1.2.3.2.E using the following criteria: LPD Engineering PLLC Page 15 New Elementary School #16 Technical Information Report, March 4, 2022 1. The existing conditions 100-year peak discharge from the area of bypassed target surfaces is increased by no more than 0.15cfs for the 15-minute time step. MGSflood output for calculations of the bypass area have been provided in Appendix B. Below is a table summarizing the flow rate results: Table 2 – Net Peak Flow Rates for Bypass Area of North Basin Peak Runoff Rates for Project Work Area Storm Event Existing Conditions Proposed Conditions Delta 100-yr 0.901 cfs 0.971 cfs 0.07 cfs 2. On-Site BMPs must be applied to bypass target surfaces per Appendix C. After applying the feasibility to each On-Site BMP to the bypass target surfaces, all BMPs were found to be infeasible. Refer to the On-Site BMP section of this report. Wetland Basin Wetland Basin Non-Target Surfaces to be Fully Dispersed A full summary of areas for the Wetland Basin can be found in Appendix B of this report. Full Dispersion: As mentioned previously, in the Wetland Basin, the majority of new and replaced impervious surfaces will be fully dispersed. Full dispersion was evaluated using the minimum design requirements per Section C.2.1 of the 2017 RSWDMA. These requirements are outlined and addressed below: 1. The total area of impervious surface being fully dispersed must be no more than 15% of the total area of native vegetated surface being preserved by a City-approved recorded tract, easement, or covenant within the same threshold discharge area. The total area of impervious surface plus nonnative pervious surface being fully dispersed must be no more than 35% of a threshold discharge area. Response: The total native vegetated retention area is approximately 134,910 SF, and the total impervious area being fully dispersed is approximately 19,750 SF, which is equal to 14.6% of the native vegetated surface. The total impervious plus the replaced non-native pervious surface being fully dispersed is approximately 43,930 SF, which is equal to 32.6% of the total native retention area. Thus, this requirement is met. 2. The runoff from a fully dispersed surface must be discharged using one of the following dispersion devices in accordance with the design specifications and maximum area of fully dispersed surface for each device as set forth in Sections C.2.1.3 through C.2.1.6. Response: Runoff from the fully dispersed surfaces will be discharged using gravel filled dispersion trenches as specified in section C.2.1.5 of the RSWDMA. Dispersion trenches will be between 30-ft to 50-ft trenches with notch board. The dispersion trenches will have flow paths ranging between 139-ft to 156’ prior to discharging into the wetland. See the design drawings and area calculations of Appendix B for further details of the dispersion trenches. LPD Engineering PLLC Page 16 New Elementary School #16 Technical Information Report, March 4, 2022 3. A native vegetated flowpath segment of at least 100 feet in length (25 feet for sheet flow from a non-native pervious surface) must be available along the flowpath that runoff would follow upon discharge from a dispersion device listen in Minimum Requirement 2 above. Response: The native vegetated flowpath will be greater than 100 feet on-site. he dispersion trenches will have flow paths ranging between 139-ft to 156’ prior to discharging into the wetland. The average slope of the flow path is not steeper than 15%. The flow path is within the existing western wetland and complies with the minimum spacing requirements. 4. For sites with septic systems, the discharge of runoff from dispersion devices must not be upgradient of a drainfield. Response: There are no septic drainfield areas downstream of the proposed dispersion trenches. 5. Dispersion devices are not allowed in critical area buffers (unless approved by DPER) or on slopes steeper than 20%. Response: No dispersion devices will be located within critical area buffers or slopes steeper than 20%. 6. Dispersion devices are not allowed within 50 feet of a steep slope hazard area, erosion hazard area, or landslide hazard area. Response: Per the King County iMap, there are no steep slope, erosion, or landslide hazard areas located on the site or within 50 feet of the dispersion devices. 7. Dispersion devices proposed on slopes steeper than 15% must be approved by a geotechnical engineer or engineering geologist unless otherwise approved by the CED. Response: The proposed dispersion devices will not be located on slopes steeper than 15%. 8. Dispersion devices proposed near slopes steeper than 15% must be approved by a geotechnical engineer or engineering geologist unless otherwise approved by the DPER staff geologist if the facility is located within a setback from the top of slope equal to the total vertical height of the slope area that is steeper than 15%. The geotechnical analysis must consider cumulative impacts from the project and surrounding areas under full built-out conditions. Response: No dispersion devices will be located within the top of slope setback for slopes steeper than 15%. 9. Dispersion devices that direct runoff toward a slope steeper than 15% may require evaluation and approval of the proposal by a geotechnical engineer or engineering geologist as determined by DPER. The geotechnical analysis must consider cumulative impacts from the project and surrounding areas under full built-out conditions. Response: No runoff from the dispersion devices will be directed towards slopes steeper than 15%. 10. Dispersion devices proposed within 200 feet of a steep slope hazard area, erosion hazard area, or landslide hazard area must be approved by a geotechnical engineer or engineering geologist unless otherwise approved by the DPER staff geologist. The geotechnical analysis must consider cumulative impacts from the project and surrounding areas under full built-out conditions. LPD Engineering PLLC Page 17 New Elementary School #16 Technical Information Report, March 4, 2022 Response: All dispersion devices will be on-site, and per the King County iMap, there are no steep slope, erosion, or landslide hazard areas located on the site or within 200 feet of the dispersion devices. 11. The dispersion of runoff must not create flooding or erosion impacts as determined by the DPER. If runoff is discharged toward a landslide hazard area, erosion hazard area, or steep slope hazard area, DPER may require evaluation and approval of the proposal by a geotechnical engineer or engineering geologist. The geotechnical analysis must consider cumulative impacts from the project and surrounding areas under full built-out conditions. Response: The dispersion of runoff will not create flooding or erosion impacts. The dispersal of stormwater will flow into a healthy vegetated area that is not within an erosion hazard area and has slopes less than 15%. Thus, it has been determined that full dispersion is feasible. Developed surfaces conforming to this strategy are considered to have a negligible impact downstream, and therefore, may be modeled as forest and are not subject to flow control or water quality facility requirements. Refer to Figure 4 – Proposed Conditions for a visual representation of the proposed dispersion measures. Full dispersion evaluation calculations are attached in Appendix B of this report. Water Quality System As mentioned previously, the project proposes more than 5,000 SF of pollution generating surface in a Basic Water Quality Treatment area, and but because schools fall into the category of a commercial development, Enhanced Basic Water Quality Treatment is triggered. Water quality treatment is required for the natural turf field, bus lane, and parking lot as they are considered to be pollution- generating surfaces by the 2017 RSWDMA. All the other impervious surfaces such as the roof, walkways, hard surface play areas, and gated fire apparatus access are non-pollution generating. The proposed water quality facility will be a Modular Wetland System, which does have General Use Level Designation (GULD) approval by Ecology for enhanced treatment. This approval is provided in Appendix B for reference. Because the water quality facilities will be located downstream of the detention systems, per section 6.2.1 of the 2017 RSWDM, the water quality design flow rate shall be the 2-year flow rate discharged by the detention facility. Therefore, a single Modular Wetland System will be used downstream of both the South Basin detention system as well as the North Basin detention system prior discharge from site. Refer to MGSFlood output in Appendix B for the 2-year release rate from the detention system (water quality design flow). Sizing of the Modular Wetland System has been conducted by the Manufacturer, BioClean and is included in Appendix B of this report. SECTION 5 – CONVEYANCE SYSTEMS ANALYSIS AND DESIGN An analysis of the onsite conveyance system was performed for the South Basin Detention Systems and the North Basin Detention System. Refer to the Conveyance Analysis Spreadsheet and accompanying MGS Flood reports included in Appendix B. Per section 1.2.4.1 of the 2017 RSWDMA, the conveyance system shall be designed to accommodate the 25-year storm event and the 100-year storm event. The 25-year peak runoff rates were compared with the full-flow capacity of the conveyance pipe. The peak runoff rates from each of the tributary areas were determined using MGS Flood with 15-minute time LPD Engineering PLLC Page 18 New Elementary School #16 Technical Information Report, March 4, 2022 steps. The full flow capacity of the conveyance pipe was determined using Manning’s equation. All pipe runs were found to have adequate capacity. SECTION 6 – SPECIAL REPORTS AND STUDIES A geotechnical report has been prepared by Associated Earth Sciences; Inc. dated November 23, 2020. This report is provided under separate cover. A wetland delineation report has been prepared by The Watershed Company, dated November 26, 2019. SECTION 7 – OTHER PERMITS Coverage under the Construction Stormwater General Permit through the Department of Ecology will be required for the project because it disturbs over one (1) acre of land area. The NOI and public noticing required for this permit will be completed later in the design process, prior to construction. SECTION 8 – CSWPPP ANALYSIS AND DESIGN The construction storm water pollution prevention plan (CSWPPP) consists of the TESC plan in the drawing set and a Stormwater Pollution Prevention Plan narrative (SWPPP) based upon Ecology’s Construction Stormwater General Permit SWPPP Template which is provided in Appendix C. The TESC plan includes temporary sediment settling ponds, sized using the methodology from the 2017 RSWDMA. A copy of the Sediment Facility Sizing Calculations worksheet and the associated output from MGS Flood used for the sediment tank sizing are included in Appendix B. SECTION 9 – BOND QUANTITIES, FACILITY SUMMARIES, AND DECLARATION OF COVENANT A Facility Summaries, and Drainage Declaration of Covenant is provided in Appendix E. The Bond Quantities Worksheet has been submitted separately. SECTION 10 – OPERATIONS AND MAINTENANCE MANUAL The Operations and Maintenance Manual is provided in Appendix D of this report. This will include maintenance recommendations associated with the conveyance pipes, catch basins, flow control structure, StormTech chamber detention facility, the Modular Wetland System (water quality facility). FIGURES Figure 1: TIR Worksheet Figure 2: Vicinity Map Figure 3: Existing Conditions Figure 4: Proposed Conditions Figure 4a: Proposed Conditions – Fully Dispersed Areas Figure 5: Soils Map Figure 6: Downstream Drainage Map KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL TECHNICAL INFORMATION REPORT (TIR) WORKSHEET Part 1 PROJECT OWNER AND PROJECT ENGINEER Part 2 PROJECT LOCATION AND DESCRIPTION Project Owner ___________________________ Phone _________________________________ Address _______________________________ _______________________________________ Project Engineer _________________________ Company ______________________________ Phone _________________________________ Project Name _________________________ DPER Permit # ________________________ Location Township ______________ Range ________________ Section ________________ Site Address __________________________ _____________________________________ Part 3 TYPE OF PERMIT APPLICATION Part 4 OTHER REVIEWS AND PERMITS  Landuse (e.g.,Subdivision / Short Subd. / UPD)  Building (e.g.,M/F / Commercial / SFR)  Clearing and Grading  Right-of-Way Use  Other _______________________  DFW HPA  COE 404  DOE Dam Safety  FEMA Floodplain  COE Wetlands  Other ________  Shoreline Management  Structural Rockery/Vault/_____  ESA Section 7 Part 5 PLAN AND REPORT INFORMATION Technical Information Report Site Improvement Plan (Engr. Plans) Type of Drainage Review (check one): Date (include revision dates): Date of Final:  Full  Targeted  Simplified  Large Project  Directed __________________ __________________ __________________ Plan Type (check one): Date (include revision dates): Date of Final:  Full  Modified  Simplified __________________ __________________ __________________ Part 6 SWDM ADJUSTMENT APPROVALS Type (circle one): Standard / Experimental / Blanket Description: (include conditions in TIR Section 2) ____________________________________________________________________________________ ____________________________________________________________________________________ ____________________________________________________________________________________ Approved Adjustment No. ______________________ Date of Approval: ______________________ 2016 Surface Water Design Manual 4/24/2016 1 Renton School District (425) 204-2340 300 South 7th Street Renton, WA 98057 Laurie Pfarr, PE LPD Engineering, PLLC (206) 725-1211 New Elementary School #16 23 North 5 East 10 Duvall Avenue NE Renton, WA 98059 X X X KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL TECHNICAL INFORMATION REPORT (TIR) WORKSHEET Part 7 MONITORING REQUIREMENTS Monitoring Required: Yes / No Start Date: _______________________ Completion Date: _______________________ Describe: _________________________________ _________________________________________ _________________________________________ Re: KCSWDM Adjustment No. ________________ Part 8 SITE COMMUNITY AND DRAINAGE BASIN Community Plan : ____________________________________________________________________ Special District Overlays: ______________________________________________________________ Drainage Basin: _____________________________________________________________________ Stormwater Requirements: ____________________________________________________________ Part 9 ONSITE AND ADJACENT SENSITIVE AREAS  River/Stream ________________________  Lake ______________________________  Wetlands ____________________________  Closed Depression ____________________  Floodplain ___________________________  Other _______________________________ _______________________________  Steep Slope __________________________  Erosion Hazard _______________________  Landslide Hazard ______________________  Coal Mine Hazard ______________________  Seismic Hazard _______________________  Habitat Protection ______________________  _____________________________________ Part 10 SOILS Soil Type _________________ _________________ _________________ _________________ Slopes _________________ _________________ _________________ _________________ Erosion Potential _________________ _________________ _________________ _________________  High Groundwater Table (within 5 feet)  Other ________________________________  Sole Source Aquifer  Seeps/Springs  Additional Sheets Attached 2016 Surface Water Design Manual 4/24/2016 2 N/A N/A N/A May Creek Drainage Basin X Alderwood gravelly sandy loam 8 to 15 % KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL TECHNICAL INFORMATION REPORT (TIR) WORKSHEET Part 11 DRAINAGE DESIGN LIMITATIONS REFERENCE  Core 2 – Offsite Analysis_________________  Sensitive/Critical Areas__________________  SEPA________________________________  LID Infeasibility________________________  Other________________________________  _____________________________________ LIMITATION / SITE CONSTRAINT _______________________________________ _______________________________________ _______________________________________ _______________________________________ _______________________________________ _______________________________________  Additional Sheets Attached Part 12 TIR SUMMARY SHEET (provide one TIR Summary Sheet per Threshold Discharge Area) Threshold Discharge Area: (name or description) Core Requirements (all 8 apply): Discharge at Natural Location Number of Natural Discharge Locations: Offsite Analysis Level: 1 / 2 / 3 dated:__________________ Flow Control (include facility summary sheet) Level: 1 / 2 / 3 or Exemption Number ____________ Flow Control BMPs _______________________________ Conveyance System Spill containment located at: _________________________ Erosion and Sediment Control / Construction Stormwater Pollution Prevention CSWPP/CESCL/ESC Site Supervisor: _____________________ Contact Phone: _________________________ After Hours Phone: _________________________ Maintenance and Operation Responsibility (circle one): Private / Public If Private, Maintenance Log Required: Yes / No Financial Guarantees and Liability Provided: Yes / No Water Quality (include facility summary sheet) Type (circle one): Basic / Sens. Lake / Enhanced Basic / Bog or Exemption No. ______________________ Landscape Management Plan: Yes / No Special Requirements (as applicable): Area Specific Drainage Requirements Type: CDA / SDO / MDP / BP / LMP / Shared Fac. / None Name: ________________________ Floodplain/Floodway Delineation Type (circle one): Major / Minor / Exemption / None 100-year Base Flood Elevation (or range): ______________ Datum: Flood Protection Facilities Describe: 2016 Surface Water Design Manual 4/24/2016 3 N/A 3 Full Dispersion N/A KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL TECHNICAL INFORMATION REPORT (TIR) WORKSHEET Part 12 TIR SUMMARY SHEET (provide one TIR Summary Sheet per Threshold Discharge Area) Source Control (commercial / industrial land use) Describe land use: Describe any structural controls: Oil Control High-use Site: Yes / No Treatment BMP: ________________________________ Maintenance Agreement: Yes / No with whom? ____________________________________ Other Drainage Structures Describe: Part 13 EROSION AND SEDIMENT CONTROL REQUIREMENTS MINIMUM ESC REQUIREMENTS DURING CONSTRUCTION  Clearing Limits  Cover Measures  Perimeter Protection  Traffic Area Stabilization  Sediment Retention  Surface Water Collection  Dewatering Control  Dust Control  Flow Control  Protection of Flow Control BMP Facilities (existing and proposed)  Maintain BMPs / Manage Project MINIMUM ESC REQUIREMENTS AFTER CONSTRUCTION  Stabilize exposed surfaces  Remove and restore Temporary ESC Facilities  Clean and remove all silt and debris, ensure operation of Permanent Facilities, restore operation of Flow Control BMP Facilities as necessary  Flag limits of SAO and open space preservation areas  Other ______________________ Part 14 STORMWATER FACILITY DESCRIPTIONS (Note: Include Facility Summary and Sketch) Flow Control Type/Description Water Quality Type/Description  Detention  Infiltration  Regional Facility  Shared Facility  Flow Control BMPs  Other ________________ ________________ ________________ ________________ ________________ ________________  Vegetated Flowpath  Wetpool  Filtration  Oil Control  Spill Control  Flow Control BMPs  Other ________________ ________________ ________________ ________________ ________________ ________________ ________________ 2016 Surface Water Design Manual 4/24/2016 4 X X X X Modular Wetland System Stormtech System Full Dispersion Full Dispersion KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL TECHNICAL INFORMATION REPORT (TIR) WORKSHEET Part 15 EASEMENTS/TRACTS Part 16 STRUCTURAL ANALYSIS  Drainage Easement  Covenant  Native Growth Protection Covenant  Tract  Other ___________________________  Cast in Place Vault  Retaining Wall  Rockery > 4’ High  Structural on Steep Slope  Other ______________________________ Part 17 SIGNATURE OF PROFESSIONAL ENGINEER I, or a civil engineer under my supervision, have visited the site. Actual site conditions as observed were incorporated into this worksheet and the attached Technical Information Report. To the best of my knowledge the information provided here is accurate. Signed/Date 2016 Surface Water Design Manual 4/24/2016 5 X X 12/15/21 1932 1st Ave,Suite 201,Seattle, WA 98101p. 206.725.1211f. 206.973.5344www.lpdengineering.comengineering pllc2021 LPD Engineering PLLC©NEW ELEMENTARY SCHOOL #163EXISTING CONDITIONS 1932 1st Ave,Suite 201,Seattle, WA 98101p. 206.725.1211f. 206.973.5344www.lpdengineering.comengineering pllc2021 LPD Engineering PLLC©NEW ELEMENTARY SCHOOL #164PROPOSED CONDITIONS 156'148'139'1932 1st Ave,Suite 201,Seattle, WA 98101p. 206.725.1211f. 206.973.5344www.lpdengineering.comengineering pllc2021 LPD Engineering PLLC©NEW ELEMENTARY SCHOOL #164APROPOSED CONDITIONSFULLY DISPERSED AREAS engineering pllc 1932 1st Ave, Suite 201, Seattle, WA 981041 p. 206.725.1211 f. 206.973.5344 www.lpdengineering.com NEW ELEMENTARY SCHOOL #16 5SOILS MAP MAP UNIT SYMBOL RdC Alderwood gravelly sandy loam, 8 to 15 percent slopes MAP UNIT NAME AmC Arents, Alderwood material, 6 to 15 percent slopes SCHOOL PROPERTY AgC Alderwood Gravelly Sandy Loam, 8 to 15 percent slopes engineering pllc2021 LPD Engineering PLLC©NEW ELEMENTARY SCHOOL #166A1932 1st Ave,Suite 201,Seattle, WA 98101p. 206.725.1211f. 206.973.5344www.lpdengineering.comDOWNSTREAM DRAINAGEMAP- SOUTH BASINAPPROXIMATELY 1/4 MILEDOWNSTREAM FROM SITEDISCHARGE POINTFROM PROPERTYDISCHARGE INTOUNNAMED CREEKSTORMWATEREVENTUALLY FLOWSINTO MAY CREEKDISCHARGE TO EXDETENTION POND12" SD SYSTEM60" SD SYSTEM12" SD30" SD30" SD30" SD engineering pllc2021 LPD Engineering PLLC©NEW ELEMENTARY SCHOOL #166B1932 1st Ave,Suite 201,Seattle, WA 98101p. 206.725.1211f. 206.973.5344www.lpdengineering.comDOWNSTREAM DRAINAGE MAP-NORTH BASIN AND WETLAND BASINDRAINAGEDITCH12" SD SYSTEM24" SDCULVERTAPPROXIMATELY 1/4 MILEDOWNSTREAM FROM SITE24" SDCULVERT15" SD SYSTEMONSITE WETLAND C TO REMAINONSITE WETLAND B TO BE FILLED12" SD SYSTEMDISCHARGE POINT TOUNNAMED CREEKSTORMWATEREVENTUALLY FLOWS INTOMAY CREEK APPENDIX A Design Drawings APPENDIX B Design Calculations and Supporting Information RENTON ES #16 Areas Spreadsheet - SOUTH BASIN Modeled Proposed Conditions SOUTH BASIN: Area Summary Pervious [SF] Impervious [SF][AC] Landscape Area 15,465 0.355 PGIS 25,150 0.577 NPGIS 2,470 0.057 Total Impervious 27,620 0.634 Total Pervious (Modeled Grass)15,420 0.354 Total Basin Disturbed 0.988 SUBBASIN: To Detention #1A and WQ Facility Pervious [SF] Impervious [SF][AC] PGIS 12,415 0.285 NPGIS 0 0.000 Landscape Area 0 0.000 Total Impervious 12,415 0.285 Total Pervious (Modeled Grass)0 0.000 Total Area 0.285 SUBBASIN: To Detention #1B and WQ Facility Pervious [SF] Impervious [SF][AC] PGIS 10,745 0.247 NPGIS 1,335 0.031 Landscape Area 4,400 0.101 Total Impervious 12,080 0.277 Total Pervious (Modeled Grass)4,400 0.101 Total Area 0.378 SUBBASIN: To Chelan Ave NE (Bypass) Pervious [SF] Impervious [SF][AC] PGIS 1,200 0.028 NPGIS 1,135 0.026 Landscape Area 11,065 0.254 Forest 0.000 Total Impervious 2,335 0.054 Total Pervious (Modeled Grass)11,065 0.254 Total Area 0.308 43,040 12,415 13,400 16,480 RENTON ES #16 Areas Spreadsheet - NORTH BASIN Modeled Proposed Conditions NORTH BASIN: Area Summary Pervious [SF] Impervious [SF][AC] Play Field (50% Grass/50% Impervious) (Non-lined)12,150 12,150 0.279 Landscape Area 61,860 1.420 PGIS 47,610 1.093 NPGIS/Play Field with Detention Underneath 82,230 1.888 Building Roof 41,170 0.945 Total Impervious 183,160 4.205 Total Pervious (Modeled Grass)74,010 1.699Total Pervious (Modeled Forested)0 0.000 Total Basin Disturbed 5.904 SUBBASIN: to Detention and WQ Facility Pervious [SF] Impervious [SF][AC] Landscape Area 19,855 0.456 PGIS 39,410 0.905 NPGIS/Play Field with Detention Underneath 74,600 1.713 Building Roof 41,170 0.945 Play Field (50% Grass/50% Impervious) (Non-lined)12,150 12,150 0.279 Total Impervious 167,330 3.841 Total Pervious (Modeled Grass)32,005 0.735 Total Area 4.576 SUBBASIN: Bypass Pervious [SF] Impervious [SF][AC] PGIS 8,200 0.188 NPGIS 7,630 0.175 Landscape Area 42,005 0.964 Total Impervious 15,830 0.363 Total Pervious (Modeled Grass)42,005 0.964 Total Area 1.328 257,170 199,335 57,835 RENTON ES #16 Areas Spreadsheet - WETLAND BASIN Modeled Proposed Conditions WETLAND BASIN: Area Summary Pervious [SF] Impervious [SF][AC] Grass Pave Fire Lane 100% Pervious 8,470 0.194 Landscape Area 15,720 0.361 Forested 155,130 3.561 NPGIS 5,745 0.132 Building Roof 14,005 0.322 Total Impervious 19,750 0.453 Total Impervious Surface Being Fully Dispersed 19,750 0.453 Total Pervious (Modeled Grass) (Non-Native Non-converted Lawn)24,190 0.555Total Pervious (Modeled Forested)155,130 3.561 Total Basin 4.570 Total Native Growth Retention Area 3.097 Percentage of Impervious Surface Dispersed to Native Retention Area Percentage of Impervious Surface plus Non-Native Pervious Dispersed to Native Retention Area SUBBASIN: Dispersion Gravel Trench A 50 LF Trench with 139-FT Flow Path Max Allowable Tributary Impervious Surface = 6,950 SF Pervious [SF] Impervious [SF][AC] Landscape Area 0.000 Grass Pave Fire Lane 3,405 0.000 NPGIS 1,148 0.026 Building Roof 5,770 0.132 Total Impervious 6,918 0.159 Total Pervious (Modeled Grass)3,405 0.078 Total Area 0.237 SUBBASIN: Dispersion Gravel Trench B 30 LF Trench with 148-FT Flow Path Max Allowable Tributary Impervious Surface = 4,400 SF Pervious [SF] Impervious [SF][AC] Landscape Area 0.000 Grass Pave Fire Lane 670 NPGIS 1,148 0.026 Building Roof 3,055 0.000 Total Impervious 4,203 0.096 Total Pervious (Modeled Grass)670 0.015 Total Area 0.112 SUBBASIN: Dispersion Gravel Trench C 50 LF Trench with 156-FT Flow Path Max Allowable Tributary Impervious Surface = 7,800 SF Pervious [SF] Impervious [SF][AC] Landscape Area 0.000 Grass Pave Fire Lane 925 199,070 10,323 4,873 134,910 14.6% 32.6% NPGIS 2,295 0.053 Building Roof 5,180 0.000 Total Impervious 7,475 0.172 Total Pervious (Modeled Grass)925 0.021 Total Area 0.193 SUBBASIN: Bypass Pervious [SF] Impervious [SF][AC] Grass Pave Fire Lane 100% Pervious 3,470 0.080 Landscape Area 15,720 0.361 Forested 155,130 3.561 NPGIS 3,450 0.079 Building Roof 0.000 Total Impervious 3,450 0.079 Total Pervious (Modeled Grass)174,320 4.002 Total Area 4.081177,770 8,400 ————————————————————————————————— MGS FLOOD PROJECT REPORT – SOUTH BASIN FLOW CONTROL Program Version: MGSFlood 4.57 Program License Number: 201410003 Project Simulation Performed on: 03/04/2022 11:53 AM Report Generation Date: 03/04/2022 11:53 AM ————————————————————————————————— Input File Name: South Basin - Detention_Combined.fld Project Name: Renton ES #16 Analysis Title: WQ/Detention - South Basin Comments: ———————————————— PRECIPITATION INPUT ———————————————— Computational Time Step (Minutes): 15 Extended Precipitation Time Series Selected Climatic Region Number: 16 Full Period of Record Available used for Routing Precipitation Station : 96004405 Puget East 44 in_5min 10/01/1939-10/01/2097 Evaporation Station : 961044 Puget East 44 in MAP Evaporation Scale Factor : 0.750 HSPF Parameter Region Number: 3 HSPF Parameter Region Name : USGS Default ********** Default HSPF Parameters Used (Not Modified by User) *************** ********************** WATERSHED DEFINITION *********************** Predevelopment/Post Development Tributary Area Summary Predeveloped Post Developed Total Subbasin Area (acres) 0.663 0.663 Area of Links that Include Precip/Evap (acres) 0.000 0.000 Total (acres) 0.663 0.663 ----------------------SCENARIO: PREDEVELOPED Number of Subbasins: 2 ---------- Subbasin : Basin to Det 1A ---------- -------Area (Acres) -------- Till Forest 0.285 ---------------------------------------------- Subbasin Total 0.285 ---------- Subbasin : Basin to Det 1B ---------- -------Area (Acres) -------- Till Forest 0.378 ---------------------------------------------- Subbasin Total 0.378 ----------------------SCENARIO: POSTDEVELOPED Number of Subbasins: 2 ---------- Subbasin : To Detention 1 ---------- -------Area (Acres) -------- Impervious 0.285 ---------------------------------------------- Subbasin Total 0.285 ---------- Subbasin : To Detention 2 ---------- -------Area (Acres) -------- Till Grass 0.101 Impervious 0.277 ---------------------------------------------- Subbasin Total 0.378 ************************* LINK DATA ******************************* ----------------------SCENARIO: PREDEVELOPED Number of Links: 1 ------------------------------------------ Link Name: South POC Link Type: Copy Downstream Link: None ************************* LINK DATA ******************************* ----------------------SCENARIO: POSTDEVELOPED Number of Links: 3 ------------------------------------------ Link Name: Detention 1A Link Type: Structure Downstream Link Name: South POC User Specified Elevation Volume Table Used Elevation (ft) Pond Volume (cu-ft) 100.00 0. 100.08 264. 100.17 527. 100.25 789. 100.33 1049. 100.42 1309. 100.50 1566. 100.58 1822. 100.67 2075. 100.75 2327. 100.83 2577. 100.92 2825. 101.00 3070. 101.08 3312. 101.17 3552. 101.25 3789. 101.33 4023. 101.42 4253. 101.50 4480. 101.58 4703. 101.67 4921. 101.75 5135. 101.83 5343. 101.92 5546. 102.00 5743. 102.08 5932. 102.17 6113. 102.25 6282. 102.33 6432. 102.42 6574. 102.50 6711. 102.58 6844. 102.67 6977. 102.75 7111. 102.83 7244. 102.92 7377. 103.00 7511. 103.08 7644. 103.17 7777. 103.25 7911. 103.33 8044. 103.42 8177. Constant Infiltration Option Used Infiltration Rate (in/hr): 0.00 Riser Geometry Riser Structure Type : Circular Riser Diameter (in) : 12.00 Common Length (ft) : 0.000 Riser Crest Elevation : 103.00 ft Hydraulic Structure Geometry Number of Devices: 1 ---Device Number 1 --- Device Type : Circular Orifice Control Elevation (ft) : 100.00 Diameter (in) : 0.35 Orientation : Horizontal Elbow : No ------------------------------------------ Link Name: Detention 1B Link Type: Structure Downstream Link Name: South POC User Specified Elevation Volume Table Used Elevation (ft) Pond Volume (cu-ft) 100.00 0. 100.08 318. 100.17 635. 100.25 950. 100.33 1264. 100.42 1576. 100.50 1886. 100.58 2193. 100.67 2499. 100.75 2802. 100.83 3103. 100.92 3401. 101.00 3695. 101.08 3987. 101.17 4275. 101.25 4560. 101.33 4840. 101.42 5118. 101.50 5390. 101.58 5657. 101.67 5919. 101.75 6176. 101.83 6424. 101.92 6668. 102.00 6903. 102.08 7130. 102.17 7345. 102.25 7546. 102.33 7724. Hydraulic Conductivity (in/hr) : 0.00 Massmann Regression Used to Estimate Hydralic Gradient Depth to Water Table (ft) : 100.00 Bio-Fouling Potential : Low Maintenance : Average or Better Riser Geometry Riser Structure Type : Circular Riser Diameter (in) : 12.00 Common Length (ft) : 0.010 Riser Crest Elevation : 101.83 ft Hydraulic Structure Geometry Number of Devices: 2 ---Device Number 1 --- Device Type : Circular Orifice Control Elevation (ft) : 100.00 Diameter (in) : 0.44 Orientation : Horizontal Elbow : Yes --- Device Number 2 --- Device Type : Rectangular Weir that Intersects the Riser Top Invert Elevation (ft) : 101.09 Length (ft) : 0.020 ------------------------------------------ Link Name: South POC Link Type: Copy Downstream Link: None **********************FLOOD FREQUENCY AND DURATION STATISTICS******************* ----------------------SCENARIO: PREDEVELOPED Number of Subbasins: 2 Number of Links: 1 ----------------------SCENARIO: POSTDEVELOPED Number of Subbasins: 2 Number of Links: 3 ***********Groundwater Recharge Summary ************* Recharge is computed as input to Perlnd Groundwater Plus Infiltration in Structures Total Predeveloped Recharge During Simulation Model Element Recharge Amount (ac-ft) ----------------------------------------------------------------------------------------------- Subbasin: Basin to Det 1A 54.218 Subbasin: Basin to Det 1B 71.911 Link: South POC 0.000 _____________________________________ Total: 126.129 Total Post Developed Recharge During Simulation Model Element Recharge Amount (ac-ft) ----------------------------------------------------------------------------------------------- Subbasin: To Detention 1 0.000 Subbasin: To Detention 2 13.008 Link: Detention 1A Not Computed Link: Detention 1B Not Computed Link: South POC 0.000 _____________________________________ Total: 13.008 Total Predevelopment Recharge is Greater than Post Developed Average Recharge Per Year, (Number of Years= 158) Predeveloped: 0.798 ac-ft/year, Post Developed: 0.082 ac-ft/year ***********Water Quality Facility Data ************* ----------------------SCENARIO: PREDEVELOPED Number of Links: 1 ********** Link: South POC ********** 2-Year Discharge Rate : 0.017 cfs 15-Minute Timestep, Water Quality Treatment Design Discharge On-line Design Discharge Rate (91% Exceedance): 0.01 cfs Off-line Design Discharge Rate (91% Exceedance): 0.01 cfs Infiltration/Filtration Statistics-------------------- Inflow Volume (ac-ft): 80.70 Inflow Volume Including PPT-Evap (ac-ft): 80.70 Total Runoff Infiltrated (ac-ft): 0.00, 0.00% Total Runoff Filtered (ac-ft): 0.00, 0.00% Primary Outflow To Downstream System (ac-ft): 80.70 Secondary Outflow To Downstream System (ac-ft): 0.00 Volume Lost to ET (ac-ft): 0.00 Percent Treated (Infiltrated+Filtered+ET)/Total Volume: 0.00% ----------------------SCENARIO: POSTDEVELOPED Number of Links: 3 ********** Link: South POC ********** 2-Year Discharge Rate : 0.008 cfs 15-Minute Timestep, Water Quality Treatment Design Discharge On-line Design Discharge Rate (91% Exceedance): 999.00 cfs Off-line Design Discharge Rate (91% Exceedance): 999.00 cfs Infiltration/Filtration Statistics-------------------- Inflow Volume (ac-ft): 306.85 Inflow Volume Including PPT-Evap (ac-ft): 306.85 Total Runoff Infiltrated (ac-ft): 0.00, 0.00% Total Runoff Filtered (ac-ft): 0.00, 0.00% Primary Outflow To Downstream System (ac-ft): 306.85 Secondary Outflow To Downstream System (ac-ft): 0.00 Volume Lost to ET (ac-ft): 0.00 Percent Treated (Infiltrated+Filtered+ET)/Total Volume: 0.00% ***********Compliance Point Results ************* Scenario Predeveloped Compliance Link: South POC Scenario Postdeveloped Compliance Link: South POC *** Point of Compliance Flow Frequency Data *** Recurrence Interval Computed Using Gringorten Plotting Position Predevelopment Runoff Postdevelopment Runoff Tr (Years) Discharge (cfs) Tr (Years) Discharge (cfs) ---------------------------------------------------------------------------------------------------------------------- 2-Year 1.705E-02 2-Year 8.384E-03 5-Year 2.733E-02 5-Year 1.538E-02 10-Year 3.564E-02 10-Year 2.377E-02 25-Year 4.899E-02 25-Year 2.926E-02 50-Year 6.159E-02 50-Year 3.507E-02 100-Year 6.535E-02 100-Year 3.728E-02 200-Year 0.104 200-Year 4.402E-02 500-Year 0.157 500-Year 5.304E-02 ** Record too Short to Compute Peak Discharge for These Recurrence Intervals **** Flow Duration Performance **** Excursion at Predeveloped 50%Q2 (Must be Less Than or Equal to 0%): -4.9% PASS Maximum Excursion from 50%Q2 to Q2 (Must be Less Than or Equal to 0%): -4.9% PASS Maximum Excursion from Q2 to Q50 (Must be less than 10%): 6.1% PASS Percent Excursion from Q2 to Q50 (Must be less than 50%): 2.7% PASS ------------------------------------------------------------------------------------------------- MEETS ALL FLOW DURATION DESIGN CRITERIA: PASS ------------------------------------------------------------------------------------------------- Renton 16 Stage-Storage Table Spreadsheet for South Detention #1A Bottom Width of Gravel Basin 40.00 ftBottom Length of Gravel Basin 100.00 ftGravel Depth Beneath Chambers 6 inchesGravel Above Chambers 6 inchesVoid Space of Gravel 40% Number of rows of Chambers 8 rows7.12 feet92.56 feet13Chambers per row 7,511 cubic feet Stage Storage Table:Calculated Stage Storage Tables Stage Height (inches)Stage Height (ft)Single Chamber Volume (CF) Cross sectional area of Chambers (SF per LF) Volume in Chambers ONLY (CF) Cross section of gravel area (SF per LF) Volume in Gravel (CF)Total Cumulative Storage (CF)Surface Area (ac)Storage (ac-ft)Infil. Through Btm of Facility (cfs) Site Elevation Stage stage area storage 0 0.000 0.00 0.00 0 0.00 0 0 0.000000 0.000000 0.000000 429.960 100.000 0 000.000 0.00 0.00 0 0.00 0 0 0.091827 0.000000 0.000000 429.960 100.000 4000 000.000 0.00 0.00 0 0.00 0 0 0.091827 0.000000 0.000000 429.960 100.000 4000.1 000.000 0.00 0.00 0 0.00 0 0 0.091827 0.000000 0.000000 429.960 100.000 4000.2 0 0 0.000 0.00 0.00 0 0.00 0 0 0.091827 0.000000 0.000000 429.960 100.000 4000.3 000.000 0.00 0.00 0 0.00 0 0 0.091827 0.000000 0.000000 429.960 100.000 4000.4 000.000 0.00 0.00 0 0.00 0 0 0.091827 0.000000 0.000000 429.960 100.000 4000.5 010.083 2.21 2.48 230 0.85 34 264 0.091827 0.006057 0.000000 430.043 100.083 4000.6 26420.167 4.41 4.96 459 1.71 68 527 0.091827 0.012101 0.000000 430.127 100.167 4000.7 527 3 0.250 6.58 7.39 684 2.61 104 789 0.091827 0.018104 0.000000 430.210 100.250 4000.8 78940.333 8.74 9.82 909 3.51 141 1049 0.091827 0.024093 0.000000 430.293 100.333 4000.9 104950.417 10.87 12.21 1130 4.45 178 1309 0.091827 0.030041 0.000000 430.377 100.417 4001 130960.500 12.97 14.57 1349 5.43 217 1566 0.091827 0.035949 0.000000 430.460 100.500 4001.1 156670.583 15.04 16.90 1564 6.43 257 1822 0.091827 0.041817 0.000000 430.543 100.583 4001.2 182280.667 17.08 19.19 1776 7.48 299 2075 0.091827 0.047643 0.000000 430.627 100.667 4001.3 207590.750 19.09 21.45 1985 8.55 342 2327 0.091827 0.053429 0.000000 430.710 100.750 4001.4 2327 10 0.833 21.06 23.66 2190 9.67 387 2577 0.091827 0.059161 0.000000 430.793 100.833 4001.5 2577110.917 23.00 25.84 2392 10.82 433 2825 0.091827 0.064852 0.000000 430.877 100.917 4001.6 2825121.000 24.89 27.97 2589 12.03 481 3070 0.091827 0.070475 0.000000 430.960 101.000 4001.7 3070131.083 26.74 30.04 2781 13.29 532 3312 0.091827 0.076044 0.000000 431.043 101.083 4001.8 3312141.167 28.54 32.07 2968 14.60 584 3552 0.091827 0.081546 0.000000 431.127 101.167 4001.9 3552151.250 30.29 34.03 3150 15.97 639 3789 0.091827 0.086979 0.000000 431.210 101.250 4002 3789161.333 31.99 35.94 3327 17.39 696 4023 0.091827 0.092345 0.000000 431.293 101.333 4002.1 4023171.417 33.64 37.80 3499 18.87 755 4253 0.091827 0.097643 0.000000 431.377 101.417 4002.2 4253181.500 35.22 39.57 3663 20.43 817 4480 0.091827 0.102846 0.000000 431.460 101.500 4002.3 4480191.583 36.74 41.28 3821 22.05 882 4703 0.091827 0.107967 0.000000 431.543 101.583 4002.4 4703201.667 38.18 42.90 3971 23.77 951 4921 0.091827 0.112981 0.000000 431.627 101.667 4002.5 4921 21 1.750 39.54 44.43 4112 25.57 1023 5135 0.091827 0.117885 0.000000 431.710 101.750 4002.6 5135221.833 40.80 45.84 4243 27.49 1100 5343 0.091827 0.122654 0.000000 431.793 101.833 4002.7 5343231.917 41.98 47.17 4366 29.50 1180 5546 0.091827 0.127315 0.000000 431.877 101.917 4002.8 5546242.000 43.06 48.38 4478 31.62 1265 5743 0.091827 0.131840 0.000000 431.960 102.000 4002.9 5743252.083 44.01 49.45 4577 33.88 1355 5932 0.091827 0.136189 0.000000 432.043 102.083 4003 5932262.167 44.81 50.35 4660 36.32 1453 6113 0.091827 0.140335 0.000000 432.127 102.167 4003.1 6113272.250 45.41 51.02 4723 38.98 1559 6282 0.091827 0.144209 0.000000 432.210 102.250 4003.2 6282 28 2.333 45.69 51.34 4752 42.00 1680 6432 0.091827 0.147649 0.000000 432.293 102.333 4003.3 6432292.417 45.85 51.52 4768 45.15 1806 6574 0.091827 0.150927 0.000000 432.377 102.417 4003.4 6574302.500 45.90 51.57 4774 48.43 1937 6711 0.091827 0.154056 0.000000 432.460 102.500 4003.5 6711312.583 45.90 51.57 4774 51.76 2070 6844 0.091827 0.157117 0.000000 432.543 102.583 4003.6 6844322.667 45.90 51.57 4774 55.09 2204 6977 0.091827 0.160178 0.000000 432.627 102.667 4003.7 6977332.750 45.90 51.57 4774 58.43 2337 7111 0.091827 0.163239 0.000000 432.710 102.750 4003.8 7111342.833 45.90 51.57 4774 61.76 2470 7244 0.091827 0.166300 0.000000 432.793 102.833 4003.9 7244 35 2.917 45.90 51.57 4774 65.09 2604 7377 0.091827 0.169361 0.000000 432.877 102.917 4004 7377363.000 45.90 51.57 4774 68.43 2737 7511 0.091827 0.172421 0.000000 432.960 103.000 4004.1 7511373.083 45.90 51.57 4774 71.76 2870 7644 0.091827 0.175482 0.000000 433.043 103.083 4004.2 7644383.167 45.90 51.57 4774 75.09 3004 7777 0.091827 0.178543 0.000000 433.127 103.167 4004.3 7777393.250 45.90 51.57 4774 78.43 3137 7911 0.091827 0.181604 0.000000 433.210 103.250 4004.4 7911403.333 45.90 51.57 4774 81.76 3270 8044 0.091827 0.184665 0.000000 433.293 103.333 4004.5 8044413.417 45.90 51.57 4774 85.09 3404 8177 0.091827 0.187726 0.000000 433.377 103.417 4004.6 8177 42 3.500 45.90 51.57 4774 88.43 3537 8311 0.091827 0.190787 0.000000 433.460 103.500 4004.7 8311 Approximate Chamber Length Total number of Chambers per RowTotal Modeled Length of Chambers Total Live Storage Volume in System Renton 16 Stage-Storage Table Spreadsheet for South Detention #1B Bottom Width of Gravel Basin 34.75 ftBottom Length of Gravel Basin 136.00 ftGravel Depth Beneath Chambers 6 inchesGravel Above Chambers 6 inchesVoid Space of Gravel 40% Number of rows of Chambers 7 rows7.12 feet128.16 feet18Chambers per row 6,424 cubic feet Stage Storage Table:Calculated Stage Storage Tables Stage Height (inches)Stage Height (ft)Single Chamber Volume (CF) Cross sectional area of Chambers (SF per LF) Volume in Chambers ONLY (CF) Cross section of gravel area (SF per LF) Volume in Gravel (CF)Total Cumulative Storage (CF)Surface Area (ac)Storage (ac-ft)Infil. Through Btm of Facility (cfs) Site Elevation Stage stage area storage 0 0.000 0.00 0.00 0 0.00 0 0 0.000000 0.000000 0.000000 429.960 100.000 0 000.000 0.00 0.00 0 0.00 0 0 0.108494 0.000000 0.000000 429.960 100.000 4726 000.000 0.00 0.00 0 0.00 0 0 0.108494 0.000000 0.000000 429.960 100.000 4726.1 000.000 0.00 0.00 0 0.00 0 0 0.108494 0.000000 0.000000 429.960 100.000 4726.2 0 0 0.000 0.00 0.00 0 0.00 0 0 0.108494 0.000000 0.000000 429.960 100.000 4726.3 000.000 0.00 0.00 0 0.00 0 0 0.108494 0.000000 0.000000 429.960 100.000 4726.4 000.000 0.00 0.00 0 0.00 0 0 0.108494 0.000000 0.000000 429.960 100.000 4726.5 010.083 2.21 2.17 278 0.72 39 318 0.108494 0.007296 0.000000 430.043 100.083 4726.6 31820.167 4.41 4.34 556 1.46 79 635 0.108494 0.014575 0.000000 430.127 100.167 4726.7 635 3 0.250 6.58 6.47 829 2.22 121 950 0.108494 0.021804 0.000000 430.210 100.250 4726.8 95040.333 8.74 8.59 1101 2.99 163 1264 0.108494 0.029016 0.000000 430.293 100.333 4726.9 126450.417 10.87 10.69 1370 3.79 206 1576 0.108494 0.036178 0.000000 430.377 100.417 4727 157660.500 12.97 12.75 1634 4.62 252 1886 0.108494 0.043291 0.000000 430.460 100.500 4727.1 188670.583 15.04 14.79 1895 5.48 298 2193 0.108494 0.050353 0.000000 430.543 100.583 4727.2 219380.667 17.08 16.79 2152 6.37 347 2499 0.108494 0.057366 0.000000 430.627 100.667 4727.3 249990.750 19.09 18.77 2405 7.29 397 2802 0.108494 0.064328 0.000000 430.710 100.750 4727.4 2802 10 0.833 21.06 20.71 2654 8.25 449 3103 0.108494 0.071224 0.000000 430.793 100.833 4727.5 3103110.917 23.00 22.61 2898 9.24 503 3401 0.108494 0.078071 0.000000 430.877 100.917 4727.6 3401121.000 24.89 24.47 3136 10.28 559 3695 0.108494 0.084833 0.000000 430.960 101.000 4727.7 3695131.083 26.74 26.29 3369 11.36 618 3987 0.108494 0.091530 0.000000 431.043 101.083 4727.8 3987141.167 28.54 28.06 3596 12.48 679 4275 0.108494 0.098143 0.000000 431.127 101.167 4727.9 4275151.250 30.29 29.78 3817 13.66 743 4560 0.108494 0.104673 0.000000 431.210 101.250 4728 4560161.333 31.99 31.45 4031 14.88 810 4840 0.108494 0.111119 0.000000 431.293 101.333 4728.1 4840171.417 33.64 33.07 4239 16.16 879 5118 0.108494 0.117482 0.000000 431.377 101.417 4728.2 5118181.500 35.22 34.63 4438 17.50 952 5390 0.108494 0.123729 0.000000 431.460 101.500 4728.3 5390191.583 36.74 36.12 4629 18.90 1028 5657 0.108494 0.129876 0.000000 431.543 101.583 4728.4 5657201.667 38.18 37.54 4811 20.38 1109 5919 0.108494 0.135890 0.000000 431.627 101.667 4728.5 5919 21 1.750 39.54 38.87 4982 21.94 1193 6176 0.108494 0.141770 0.000000 431.710 101.750 4728.6 6176221.833 40.80 40.11 5141 23.60 1284 6424 0.108494 0.147484 0.000000 431.793 101.833 4728.7 6424231.917 41.98 41.27 5289 25.33 1378 6668 0.108494 0.153065 0.000000 431.877 101.917 4728.8 6668242.000 43.06 42.33 5426 27.17 1478 6903 0.108494 0.158480 0.000000 431.960 102.000 4728.9 6903252.083 44.01 43.27 5545 29.13 1585 7130 0.108494 0.163678 0.000000 432.043 102.083 4729 7130262.167 44.81 44.05 5646 31.24 1699 7345 0.108494 0.168626 0.000000 432.127 102.167 4729.1 7345272.250 45.41 44.64 5722 33.54 1825 7546 0.108494 0.173241 0.000000 432.210 102.250 4729.2 7546282.333 45.69 44.92 5757 36.16 1967 7724 0.108494 0.177324 0.000000 432.293 102.333 4729.3 7724 29 2.417 45.85 45.08 5777 38.90 2116 7893 0.108494 0.181207 0.000000 432.377 102.417 4729.4 7893302.500 45.90 45.13 5783 41.75 2271 8055 0.108494 0.184906 0.000000 432.460 102.500 4729.5 8055312.583 45.90 45.13 5783 44.64 2429 8212 0.108494 0.188523 0.000000 432.543 102.583 4729.6 8212322.667 45.90 45.13 5783 47.54 2586 8370 0.108494 0.192139 0.000000 432.627 102.667 4729.7 8370 33 2.750 45.90 45.13 5783 50.44 2744 8527 0.108494 0.195756 0.000000 432.710 102.750 4729.8 8527342.833 45.90 45.13 5783 53.33 2901 8685 0.108494 0.199372 0.000000 432.793 102.833 4729.9 8685352.917 45.90 45.13 5783 56.23 3059 8842 0.108494 0.202989 0.000000 432.877 102.917 4730 8842363.000 45.90 45.13 5783 59.12 3216 9000 0.108494 0.206605 0.000000 432.960 103.000 4730.1 9000373.083 45.90 45.13 5783 62.02 3374 9157 0.108494 0.210222 0.000000 433.043 103.083 4730.2 9157383.167 45.90 45.13 5783 64.92 3531 9315 0.108494 0.213838 0.000000 433.127 103.167 4730.3 9315393.250 45.90 45.13 5783 67.81 3689 9472 0.108494 0.217455 0.000000 433.210 103.250 4730.4 9472 40 3.333 45.90 45.13 5783 70.71 3846 9630 0.108494 0.221071 0.000000 433.293 103.333 4730.5 9630413.417 45.90 45.13 5783 73.60 4004 9787 0.108494 0.224688 0.000000 433.377 103.417 4730.6 9787423.500 45.90 45.13 5783 76.50 4162 9945 0.108494 0.228304 0.000000 433.460 103.500 4730.7 9945 Approximate Chamber Length Total number of Chambers per RowTotal Modeled Length of Chambers Total Live Storage Volume in System ————————————————————————————————— MGS FLOOD PROJECT REPORT – SOUTH BASIN BYPASS Program Version: MGSFlood 4.57 Program License Number: 201410003 Project Simulation Performed on: 12/17/2021 10:51 AM Report Generation Date: 12/17/2021 10:51 AM ————————————————————————————————— Input File Name: South Basin - just bypass.fld Project Name: Renton ES #16 Analysis Title: South Basin Comments: Bypass ———————————————— PRECIPITATION INPUT ———————————————— Computational Time Step (Minutes): 15 Extended Precipitation Time Series Selected Climatic Region Number: 16 Full Period of Record Available used for Routing Precipitation Station : 96004405 Puget East 44 in_5min 10/01/1939-10/01/2097 Evaporation Station : 961044 Puget East 44 in MAP Evaporation Scale Factor : 0.750 HSPF Parameter Region Number: 3 HSPF Parameter Region Name : USGS Default ********** Default HSPF Parameters Used (Not Modified by User) *************** ********************** WATERSHED DEFINITION *********************** Predevelopment/Post Development Tributary Area Summary Predeveloped Post Developed Total Subbasin Area (acres) 0.308 0.308 Area of Links that Include Precip/Evap (acres) 0.000 0.000 Total (acres) 0.308 0.308 ----------------------SCENARIO: PREDEVELOPED Number of Subbasins: 1 ---------- Subbasin : South Basin ---------- -------Area (Acres) -------- Till Grass 0.288 Impervious 0.020 ---------------------------------------------- Subbasin Total 0.308 ----------------------SCENARIO: POSTDEVELOPED Number of Subbasins: 1 ---------- Subbasin : Bypass ---------- -------Area (Acres) -------- Till Grass 0.254 Impervious 0.054 ---------------------------------------------- Subbasin Total 0.308 ************************* LINK DATA ******************************* ----------------------SCENARIO: PREDEVELOPED Number of Links: 0 ************************* LINK DATA ******************************* ----------------------SCENARIO: POSTDEVELOPED Number of Links: 1 ------------------------------------------ Link Name: Basin POC Link Type: Copy Downstream Link: None **********************FLOOD FREQUENCY AND DURATION STATISTICS******************* ----------------------SCENARIO: PREDEVELOPED Number of Subbasins: 1 Number of Links: 0 ----------------------SCENARIO: POSTDEVELOPED Number of Subbasins: 1 Number of Links: 1 ***********Groundwater Recharge Summary ************* Recharge is computed as input to Perlnd Groundwater Plus Infiltration in Structures Total Predeveloped Recharge During Simulation Model Element Recharge Amount (ac-ft) ----------------------------------------------------------------------------------------------- Subbasin: South Basin 37.093 _____________________________________ Total: 37.093 Total Post Developed Recharge During Simulation Model Element Recharge Amount (ac-ft) ----------------------------------------------------------------------------------------------- Subbasin: Bypass 32.714 Link: Basin POC 0.000 _____________________________________ Total: 32.714 Total Predevelopment Recharge is Greater than Post Developed Average Recharge Per Year, (Number of Years= 158) Predeveloped: 0.235 ac-ft/year, Post Developed: 0.207 ac-ft/year ***********Water Quality Facility Data ************* ----------------------SCENARIO: PREDEVELOPED Number of Links: 0 ----------------------SCENARIO: POSTDEVELOPED Number of Links: 1 ********** Link: Basin POC ********** 2-Year Discharge Rate : 0.049 cfs 15-Minute Timestep, Water Quality Treatment Design Discharge On-line Design Discharge Rate (91% Exceedance): 0.01 cfs Off-line Design Discharge Rate (91% Exceedance): 0.01 cfs Infiltration/Filtration Statistics-------------------- Inflow Volume (ac-ft): 89.48 Inflow Volume Including PPT-Evap (ac-ft): 89.48 Total Runoff Infiltrated (ac-ft): 0.00, 0.00% Total Runoff Filtered (ac-ft): 0.00, 0.00% Primary Outflow To Downstream System (ac-ft): 89.48 Secondary Outflow To Downstream System (ac-ft): 0.00 Volume Lost to ET (ac-ft): 0.00 Percent Treated (Infiltrated+Filtered+ET)/Total Volume: 0.00% ***********Compliance Point Results ************* Scenario Predeveloped Compliance Subbasin: South Basin Scenario Postdeveloped Compliance Link: Basin POC *** Point of Compliance Flow Frequency Data *** Recurrence Interval Computed Using Gringorten Plotting Position Predevelopment Runoff Postdevelopment Runoff Tr (Years) Discharge (cfs) Tr (Years) Discharge (cfs) ---------------------------------------------------------------------------------------------------------------------- 2-Year 4.033E-02 2-Year 4.919E-02 5-Year 6.402E-02 5-Year 7.440E-02 10-Year 8.738E-02 10-Year 9.641E-02 25-Year 0.120 25-Year 0.130 50-Year 0.158 50-Year 0.166 100-Year 0.191 100-Year 0.209 200-Year 0.199 200-Year 0.215 500-Year 0.210 500-Year 0.222 ** Record too Short to Compute Peak Discharge for These Recurrence Intervals ————————————————————————————————— MGS FLOOD PROJECT REPORT – NORTH BASIN FLOW CONTROL Program Version: MGSFlood 4.57 Program License Number: 201410003 Project Simulation Performed on: 12/17/2021 11:01 AM Report Generation Date: 12/17/2021 11:01 AM ————————————————————————————————— Input File Name: North Basin - Detention.fld Project Name: Renton ES #16 Analysis Title: WQ/Detention - North Basin Comments: ———————————————— PRECIPITATION INPUT ———————————————— Computational Time Step (Minutes): 15 Extended Precipitation Time Series Selected Climatic Region Number: 16 Full Period of Record Available used for Routing Precipitation Station : 96004405 Puget East 44 in_5min 10/01/1939-10/01/2097 Evaporation Station : 961044 Puget East 44 in MAP Evaporation Scale Factor : 0.750 HSPF Parameter Region Number: 3 HSPF Parameter Region Name : USGS Default ********** Default HSPF Parameters Used (Not Modified by User) *************** ********************** WATERSHED DEFINITION *********************** Predevelopment/Post Development Tributary Area Summary Predeveloped Post Developed Total Subbasin Area (acres) 4.576 4.576 Area of Links that Include Precip/Evap (acres) 0.000 0.000 Total (acres) 4.576 4.576 ----------------------SCENARIO: PREDEVELOPED Number of Subbasins: 1 ---------- Subbasin : North Basin ---------- -------Area (Acres) -------- Till Forest 4.120 Till Grass 0.456 ---------------------------------------------- Subbasin Total 4.576 ----------------------SCENARIO: POSTDEVELOPED Number of Subbasins: 1 ---------- Subbasin : To Detention/WQ ---------- -------Area (Acres) -------- Till Grass 0.735 Impervious 3.841 ---------------------------------------------- Subbasin Total 4.576 ************************* LINK DATA ******************************* ----------------------SCENARIO: PREDEVELOPED Number of Links: 0 ************************* LINK DATA ******************************* ----------------------SCENARIO: POSTDEVELOPED Number of Links: 1 ------------------------------------------ Link Name: Detention 2 Link Type: Structure Downstream Link: None User Specified Elevation Volume Table Used Elevation (ft) Pond Volume (cu-ft) 100.00 0. 100.08 1842. 100.17 3673. 100.25 5501. 100.33 7323. 100.42 9057. 100.50 10949. 100.58 12749. 100.67 14547. 100.75 16336. 100.83 18117. 100.92 19889. 101.00 21653. 101.08 23409. 101.17 25153. 101.25 26889. 101.33 28617. 101.42 30331. 101.50 32034. 101.58 33725. 101.67 35406. 101.75 37070. 101.83 38722. 101.92 40358. 102.00 41980. 102.08 43583. 102.17 45171. 102.25 46738. 102.33 48287. 102.42 49817. 102.50 51322. 102.58 52808. 102.67 54266. 102.75 55698. 102.83 57103. 102.92 58477. 103.00 59818. 103.08 61120. 103.17 62379. 103.25 63592. 103.33 64743. 103.42 65800. 103.50 66776. 103.58 67721. 103.67 68641. 103.75 69523. 103.83 70387. 103.92 71252. 104.00 72116. 104.08 72981. 104.17 73845. 104.25 74710. 104.33 75574. 104.42 76439. 104.50 77303. 104.58 78168. 104.67 79032. 104.75 79897. 104.83 80761. 104.92 81626. 105.00 82490. Constant Infiltration Option Used Infiltration Rate (in/hr): 0.00 Riser Geometry Riser Structure Type : Circular Riser Diameter (in) : 18.00 Common Length (ft) : 0.010 Riser Crest Elevation : 104.75 ft Hydraulic Structure Geometry Number of Devices: 3 ---Device Number 1 --- Device Type : Circular Orifice Control Elevation (ft) : 100.00 Diameter (in) : 1.34 Orientation : Horizontal Elbow : No ---Device Number 2 --- Device Type : Circular Orifice Control Elevation (ft) : 102.00 Diameter (in) : 1.17 Orientation : Horizontal Elbow : Yes ---Device Number 3 --- Device Type : Circular Orifice Control Elevation (ft) : 102.83 Diameter (in) : 2.00 Orientation : Horizontal Elbow : Yes **********************FLOOD FREQUENCY AND DURATION STATISTICS******************* ----------------------SCENARIO: PREDEVELOPED Number of Subbasins: 1 Number of Links: 0 ----------------------SCENARIO: POSTDEVELOPED Number of Subbasins: 1 Number of Links: 1 ********** Link: Detention 2 ********** Link WSEL Stats WSEL Frequency Data(ft) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) WSEL Peak (ft) ====================================== 1.05-Year 101.216 1.11-Year 101.337 1.25-Year 101.510 2.00-Year 102.006 3.33-Year 102.407 5-Year 102.781 10-Year 103.438 25-Year 103.816 50-Year 104.117 100-Year 104.199 ***********Groundwater Recharge Summary ************* Recharge is computed as input to Perlnd Groundwater Plus Infiltration in Structures Total Predeveloped Recharge During Simulation Model Element Recharge Amount (ac-ft) ----------------------------------------------------------------------------------------------- Subbasin: North Basin 842.519 _____________________________________ Total: 842.519 Total Post Developed Recharge During Simulation Model Element Recharge Amount (ac-ft) ----------------------------------------------------------------------------------------------- Subbasin: To Detention/WQ 94.665 Link: Detention 2 0.000 _____________________________________ Total: 94.665 Total Predevelopment Recharge is Greater than Post Developed Average Recharge Per Year, (Number of Years= 158) Predeveloped: 5.332 ac-ft/year, Post Developed: 0.599 ac-ft/year ***********Water Quality Facility Data ************* ----------------------SCENARIO: PREDEVELOPED Number of Links: 0 ----------------------SCENARIO: POSTDEVELOPED Number of Links: 1 ********** Link: Detention 2 ********** Basic Wet Pond Volume (91% Exceedance): 19219. cu-ft Computed Large Wet Pond Volume, 1.5*Basic Volume: 28828. cu-ft 2-Year Discharge Rate : 0.070 cfs 15-Minute Timestep, Water Quality Treatment Design Discharge On-line Design Discharge Rate (91% Exceedance): 0.59 cfs Off-line Design Discharge Rate (91% Exceedance): 0.33 cfs Infiltration/Filtration Statistics-------------------- Inflow Volume (ac-ft): 2108.59 Inflow Volume Including PPT-Evap (ac-ft): 2108.59 Total Runoff Infiltrated (ac-ft): 0.00, 0.00% Total Runoff Filtered (ac-ft): 0.00, 0.00% Primary Outflow To Downstream System (ac-ft): 2108.23 Secondary Outflow To Downstream System (ac-ft): 0.00 Volume Lost to ET (ac-ft): 0.00 Percent Treated (Infiltrated+Filtered+ET)/Total Volume: 0.00% ***********Compliance Point Results ************* Scenario Predeveloped Compliance Subbasin: North Basin Scenario Postdeveloped Compliance Link: Detention 2 *** Point of Compliance Flow Frequency Data *** Recurrence Interval Computed Using Gringorten Plotting Position Predevelopment Runoff Postdevelopment Runoff Tr (Years) Discharge (cfs) Tr (Years) Discharge (cfs) ---------------------------------------------------------------------------------------------------------------------- 2-Year 0.136 2-Year 6.982E-02 5-Year 0.238 5-Year 0.111 10-Year 0.325 10-Year 0.209 25-Year 0.418 25-Year 0.241 50-Year 0.554 50-Year 0.263 100-Year 0.619 100-Year 0.268 200-Year 0.887 200-Year 0.487 500-Year 1.246 500-Year 0.782 ** Record too Short to Compute Peak Discharge for These Recurrence Intervals **** Flow Duration Performance **** Excursion at Predeveloped 50%Q2 (Must be Less Than or Equal to 0%): -7.2% PASS Maximum Excursion from 50%Q2 to Q2 (Must be Less Than or Equal to 0%): -0.1% PASS Maximum Excursion from Q2 to Q50 (Must be less than 10%): 9.7% PASS Percent Excursion from Q2 to Q50 (Must be less than 50%): 8.5% PASS ------------------------------------------------------------------------------------------------- MEETS ALL FLOW DURATION DESIGN CRITERIA: PASS ------------------------------------------------------------------------------------------------- Renton 16 Stage‐Storage Table Spreadsheet for Detention Facility #2 Bottom Width of Gravel Basin 95.00 ft Bottom Length of Gravel Basin 273.00 ft Gravel Depth Beneath Chambers 9 inches Gravel Above Chambers 12 inches Void Space of Gravel 40% Number of rows of Chambers 13 rows Chamber Length 7.22 feet Total Length of Chambers 263.87 feet Total number of Chambers per Row 36 Chambers per row Total Storage Volume in System 79,897 cubic feet Stage Storage Table: Stage Height (inches) Stage Height (ft)Single Chamber Volume  (CF) Cross sectional area of  Chambers  (SF per LF) Total Volume in  Chambers (CF) Cross section of gravel  area  (SF per LF) Volume in Gravel (CF)Total Cumulative Storage  (CF)Surface Area (ac) Storage (ac‐ft)Infil. Through Btm of  Facility (cfs)stage area storage 0 0.000 0.00 0.00 0 0.00 0 0 0.000000 0.000000 0.000000 100.000 0 00 0.000 0.00 0.00 0 0.00 0 0 0.595386 0.000000 0.000000 100.000 25935 0 0 0.000 0.00 0.00 0 0.00 0 0 0.595386 0.000000 0.000000 100.000 25935.1 00 0.000 0.00 0.00 0 0.00 0 0 0.595386 0.000000 0.000000 100.000 25935.2 0 0 0.000 0.00 0.00 0 0.00 0 0 0.595386 0.000000 0.000000 100.000 25935.3 00 0.000 0.00 0.00 0 0.00 0 0 0.595386 0.000000 0.000000 100.000 25935.4 0 0 0.000 0.00 0.00 0 0.00 0 0 0.595386 0.000000 0.000000 100.000 25935.5 0 0 0.000 0.00 0.00 0 0.00 0 0 0.595386 0.000000 0.000000 100.000 25935.6 0 0 0.000 0.00 0.00 0 0.00 0 0 0.595386 0.000000 0.000000 100.000 25935.7 0 0 0.000 0.00 0.00 0 0.00 0 0 0.595386 0.000000 0.000000 100.000 25935.8 0 1 0.083 3.51 6.32 1668 1.60 174 1842 0.595386 0.042287 0.000000 100.083 25935.9 18422 0.167 6.98 12.57 3316 3.27 357 3673 0.595386 0.084318 0.000000 100.167 25936 3673 3 0.250 10.44 18.80 4960 4.95 541 5501 0.595386 0.126285 0.000000 100.250 25936.1 55014 0.333 13.88 24.99 6595 6.67 729 7323 0.595386 0.168124 0.000000 100.333 25936.2 7323 5 0.417 17.00 30.61 8077 8.97 980 9057 0.595386 0.207917 0.000000 100.417 25936.3 90576 0.500 20.69 37.25 9830 10.25 1119 10949 0.595386 0.251354 0.000000 100.500 25936.4 10949 7 0.583 24.05 43.30 11426 12.11 1323 12749 0.595386 0.292682 0.000000 100.583 25936.5 127498 0.667 27.40 49.34 13018 14.00 1529 14547 0.595386 0.333946 0.000000 100.667 25936.6 14547 9 0.750 30.72 55.31 14595 15.94 1740 16336 0.595386 0.375018 0.000000 100.750 25936.7 1633610 0.833 34.01 61.24 16159 17.93 1958 18117 0.595386 0.415898 0.000000 100.833 25936.8 18117 11 0.917 37.27 67.11 17707 19.98 2181 19889 0.595386 0.456586 0.000000 100.917 25936.9 1988912 1.000 40.50 72.92 19242 22.08 2411 21653 0.595386 0.497082 0.000000 101.000 25937 21653 13 1.083 43.70 78.68 20762 24.23 2646 23409 0.595386 0.537387 0.000000 101.083 25937.1 2340914 1.167 46.86 84.37 22264 26.46 2889 25153 0.595386 0.577436 0.000000 101.167 25937.2 25153 15 1.250 49.99 90.01 23751 28.74 3138 26889 0.595386 0.617293 0.000000 101.250 25937.3 26889 16 1.333 53.09 95.59 25224 31.08 3393 28617 0.595386 0.656959 0.000000 101.333 25937.4 28617 17 1.417 56.14 101.08 26673 33.50 3658 30331 0.595386 0.696304 0.000000 101.417 25937.5 30331 18 1.500 59.15 106.50 28103 36.00 3931 32034 0.595386 0.735394 0.000000 101.500 25937.6 32034 19 1.583 62.12 111.85 29514 38.57 4211 33725 0.595386 0.774229 0.000000 101.583 25937.7 33725 20 1.667 65.05 117.13 30906 41.21 4500 35406 0.595386 0.812807 0.000000 101.667 25937.8 35406 21 1.750 67.92 122.29 32270 43.96 4800 37070 0.595386 0.851002 0.000000 101.750 25937.9 37070 22 1.833 70.75 127.39 33614 46.78 5108 38722 0.595386 0.888941 0.000000 101.833 25938 38722 23 1.917 73.52 132.38 34930 49.71 5428 40358 0.595386 0.926497 0.000000 101.917 25938.1 40358 24 2.000 76.24 137.27 36223 52.73 5758 41980 0.595386 0.963733 0.000000 102.000 25938.2 41980 25 2.083 78.89 142.05 37482 55.87 6101 43583 0.595386 1.000521 0.000000 102.083 25938.3 43583 26 2.167 81.49 146.73 38717 59.11 6454 45171 0.595386 1.036990 0.000000 102.167 25938.4 4517127 2.250 84.01 151.26 39914 62.49 6823 46738 0.595386 1.072947 0.000000 102.250 25938.5 46738 28 2.333 86.47 155.69 41083 65.97 7204 48287 0.595386 1.108521 0.000000 102.333 25938.6 4828729 2.417 88.86 160.00 42218 69.59 7599 49817 0.595386 1.143647 0.000000 102.417 25938.7 49817 30 2.500 91.16 164.14 43311 73.36 8011 51322 0.595386 1.178198 0.000000 102.500 25938.8 5132231 2.583 93.39 168.15 44371 77.26 8437 52808 0.595386 1.212301 0.000000 102.583 25938.9 52808 32 2.667 95.52 171.99 45383 81.34 8883 54266 0.595386 1.245765 0.000000 102.667 25939 5426633 2.750 97.56 175.66 46352 85.59 9346 55698 0.595386 1.278654 0.000000 102.750 25939.1 55698 34 2.833 99.50 179.16 47274 90.01 9829 57103 0.595386 1.310903 0.000000 102.833 25939.2 5710335 2.917 101.33 182.45 48143 94.63 10334 58477 0.595386 1.342449 0.000000 102.917 25939.3 58477 36 3.000 103.04 185.53 48956 99.47 10862 59818 0.595386 1.373227 0.000000 103.000 25939.4 5981837 3.083 104.61 188.36 49701 104.56 11418 61120 0.595386 1.403111 0.000000 103.083 25939.5 61120 38 3.167 106.03 190.91 50376 109.92 12003 62379 0.595386 1.432036 0.000000 103.167 25939.6 6237939 3.250 107.28 193.16 50970 115.59 12622 63592 0.595386 1.459873 0.000000 103.250 25939.7 63592 40 3.333 108.31 195.02 51459 121.65 13284 64743 0.595386 1.486305 0.000000 103.333 25939.8 64743 41 3.417 109.00 196.26 51787 128.32 14013 65800 0.595386 1.510562 0.000000 103.417 25939.9 65800 42 3.500 109.40 196.98 51977 135.52 14799 66776 0.595386 1.532966 0.000000 103.500 25940 66776 43 3.583 109.69 197.50 52115 142.91 15606 67721 0.595386 1.554666 0.000000 103.583 25940.1 67721 44 3.667 109.89 197.86 52210 150.47 16431 68641 0.595386 1.575791 0.000000 103.667 25940.2 68641 45 3.750 109.95 197.97 52239 158.28 17284 69523 0.595386 1.596021 0.000000 103.750 25940.3 69523 46 3.833 109.95 197.97 52239 166.20 18149 70387 0.595386 1.615867 0.000000 103.833 25940.4 70387 47 3.917 109.95 197.97 52239 174.11 19013 71252 0.595386 1.635713 0.000000 103.917 25940.5 71252 48 4.000 109.95 197.97 52239 182.03 19878 72116 0.595386 1.655559 0.000000 104.000 25940.6 72116 49 4.083 109.95 197.97 52239 189.95 20742 72981 0.595386 1.675405 0.000000 104.083 25940.7 72981 50 4.167 109.95 197.97 52239 197.86 21607 73845 0.595386 1.695252 0.000000 104.167 25940.8 73845 51 4.250 109.95 197.97 52239 205.78 22471 74710 0.595386 1.715098 0.000000 104.250 25940.9 74710 52 4.333 109.95 197.97 52239 213.70 23336 75574 0.595386 1.734944 0.000000 104.333 25941 75574 53 4.417 109.95 197.97 52239 221.61 24200 76439 0.595386 1.754790 0.000000 104.417 25941.1 7643954 4.500 109.95 197.97 52239 229.53 25065 77303 0.595386 1.774636 0.000000 104.500 25941.2 77303 55 4.583 109.95 197.97 52239 237.45 25929 78168 0.595386 1.794483 0.000000 104.583 25941.3 7816856 4.667 109.95 197.97 52239 245.36 26794 79032 0.595386 1.814329 0.000000 104.667 25941.4 79032 57 4.750 109.95 197.97 52239 253.28 27658 79897 0.595386 1.834175 0.000000 104.750 25941.5 7989758 4.833 109.95 197.97 52239 261.20 28523 80761 0.595386 1.854021 0.000000 104.833 25941.6 80761 59 4.917 109.95 197.97 52239 269.11 29387 81626 0.595386 1.873867 0.000000 104.917 25941.7 8162660 5.000 109.95 197.97 52239 277.03 30252 82490 0.595386 1.893714 0.000000 105.000 25941.8 82490 61 5.083 109.95 197.97 52239 284.95 31116 83355 0.595386 1.913560 0.000000 105.083 25941.9 83355 62 5.167 109.95 197.97 52239 292.86 31981 84219 0.595386 1.933406 0.000000 105.167 25942 84219 63 5.250 109.95 197.97 52239 300.78 32845 85084 0.595386 1.953252 0.000000 105.250 25942.1 85084 64 5.333 110.95 199.77 52714 306.90 33513 86227 0.595386 1.979492 0.000000 105.333 25942.2 86227 65 5.417 111.95 201.57 53189 313.01 34181 87370 0.595386 2.005731 0.000000 105.417 25942.3 87370 66 5.500 112.95 203.37 53664 319.13 34849 88513 0.595386 2.031971 0.000000 105.500 25942.4 88513 67 5.583 113.95 205.17 54139 325.24 35517 89656 0.595386 2.058210 0.000000 105.583 25942.5 89656 68 5.667 114.95 206.97 54614 331.36 36184 90799 0.595386 2.084449 0.000000 105.667 25942.6 90799 69 5.750 115.95 208.77 55089 337.48 36852 91942 0.595386 2.110689 0.000000 105.750 25942.7 91942 70 5.833 116.95 210.57 55564 343.59 37520 93085 0.595386 2.136928 0.000000 105.833 25942.8 93085 71 5.917 117.95 212.38 56039 349.71 38188 94228 0.595386 2.163168 0.000000 105.917 25942.9 9422872 6.000 118.95 214.18 56515 355.82 38856 95371 0.595386 2.189407 0.000000 106.000 25943 95371 ————————————————————————————————— MGS FLOOD PROJECT REPORT– NORTH BASIN BYPASS Program Version: MGSFlood 4.57 Program License Number: 201410003 Project Simulation Performed on: 12/17/2021 11:05 AM Report Generation Date: 12/17/2021 11:05 AM ————————————————————————————————— Input File Name: North Basin - just bypass.fld Project Name: Renton ES #16 Analysis Title: North Basin Comments: Bypass ———————————————— PRECIPITATION INPUT ———————————————— Computational Time Step (Minutes): 15 Extended Precipitation Time Series Selected Climatic Region Number: 16 Full Period of Record Available used for Routing Precipitation Station : 96004405 Puget East 44 in_5min 10/01/1939-10/01/2097 Evaporation Station : 961044 Puget East 44 in MAP Evaporation Scale Factor : 0.750 HSPF Parameter Region Number: 3 HSPF Parameter Region Name : USGS Default ********** Default HSPF Parameters Used (Not Modified by User) *************** ********************** WATERSHED DEFINITION *********************** Predevelopment/Post Development Tributary Area Summary Predeveloped Post Developed Total Subbasin Area (acres) 1.327 1.327 Area of Links that Include Precip/Evap (acres) 0.000 0.000 Total (acres) 1.327 1.327 ----------------------SCENARIO: PREDEVELOPED Number of Subbasins: 1 ---------- Subbasin : North Basin ---------- -------Area (Acres) -------- Till Grass 1.095 Impervious 0.232 ---------------------------------------------- Subbasin Total 1.327 ----------------------SCENARIO: POSTDEVELOPED Number of Subbasins: 1 ---------- Subbasin : Bypass ---------- -------Area (Acres) -------- Till Grass 0.964 Impervious 0.363 ---------------------------------------------- Subbasin Total 1.327 ************************* LINK DATA ******************************* ----------------------SCENARIO: PREDEVELOPED Number of Links: 0 ************************* LINK DATA ******************************* ----------------------SCENARIO: POSTDEVELOPED Number of Links: 1 ------------------------------------------ Link Name: Basin POC Link Type: Copy Downstream Link: None **********************FLOOD FREQUENCY AND DURATION STATISTICS******************* ----------------------SCENARIO: PREDEVELOPED Number of Subbasins: 1 Number of Links: 0 ----------------------SCENARIO: POSTDEVELOPED Number of Subbasins: 1 Number of Links: 1 ***********Groundwater Recharge Summary ************* Recharge is computed as input to Perlnd Groundwater Plus Infiltration in Structures Total Predeveloped Recharge During Simulation Model Element Recharge Amount (ac-ft) ----------------------------------------------------------------------------------------------- Subbasin: North Basin 141.032 _____________________________________ Total: 141.032 Total Post Developed Recharge During Simulation Model Element Recharge Amount (ac-ft) ----------------------------------------------------------------------------------------------- Subbasin: Bypass 124.159 Link: Basin POC 0.000 _____________________________________ Total: 124.159 Total Predevelopment Recharge is Greater than Post Developed Average Recharge Per Year, (Number of Years= 158) Predeveloped: 0.893 ac-ft/year, Post Developed: 0.786 ac-ft/year ***********Water Quality Facility Data ************* ----------------------SCENARIO: PREDEVELOPED Number of Links: 0 ----------------------SCENARIO: POSTDEVELOPED Number of Links: 1 ********** Link: Basin POC ********** 2-Year Discharge Rate : 0.250 cfs 15-Minute Timestep, Water Quality Treatment Design Discharge On-line Design Discharge Rate (91% Exceedance): 0.06 cfs Off-line Design Discharge Rate (91% Exceedance): 0.03 cfs Infiltration/Filtration Statistics-------------------- Inflow Volume (ac-ft): 418.94 Inflow Volume Including PPT-Evap (ac-ft): 418.94 Total Runoff Infiltrated (ac-ft): 0.00, 0.00% Total Runoff Filtered (ac-ft): 0.00, 0.00% Primary Outflow To Downstream System (ac-ft): 418.94 Secondary Outflow To Downstream System (ac-ft): 0.00 Volume Lost to ET (ac-ft): 0.00 Percent Treated (Infiltrated+Filtered+ET)/Total Volume: 0.00% ***********Compliance Point Results ************* Scenario Predeveloped Compliance Subbasin: North Basin Scenario Postdeveloped Compliance Link: Basin POC *** Point of Compliance Flow Frequency Data *** Recurrence Interval Computed Using Gringorten Plotting Position Predevelopment Runoff Postdevelopment Runoff Tr (Years) Discharge (cfs) Tr (Years) Discharge (cfs) ---------------------------------------------------------------------------------------------------------------------- 2-Year 0.212 2-Year 0.250 5-Year 0.320 5-Year 0.356 10-Year 0.415 10-Year 0.445 25-Year 0.560 25-Year 0.590 50-Year 0.715 50-Year 0.770 100-Year 0.901 100-Year 0.971 200-Year 0.926 200-Year 0.988 500-Year 0.956 500-Year 1.004 ** Record too Short to Compute Peak Discharge for These Recurrence Intervals August 2021 GENERAL USE LEVEL DESIGNATION FOR BASIC (TSS) ENHANCED AND PHOSPHORUS TREATMENT For MWS-Linear Modular Wetland Ecology’s Decision Based on Modular Wetland Systems, Inc, application submissions, including the Technical Evaluation Report, dated April 1, 2014, Ecology hereby issues the following use level designation: 1. General Use Level Designation (GULD) for the MWS-Linear Modular Wetland Stormwater Treatment System for Basic, Phosphorus, and Enhanced treatment  Sized at a hydraulic loading rate of:  1 gallon per minute (gpm) per square foot (sq ft) of Wetland Cell Surface Area  Prefilter box (approved at either 22 inches or 33 inches tall)  3.0 gpm/sq ft of prefilter box surface area for moderate pollutant loading rates (low to medium density residential basins).  2.1 gpm/sq ft of prefilter box surface area for high pollutant loading rates (commercial and industrial basins). 2. Ecology approves the MWS – Linear Modular Wetland Stormwater Treatment System units for Basic, Phosphorus, and Enhanced treatment at the hydraulic loading rate listed above. Designers shall calculate the water quality design flow rates using the following procedures:  Western Washington: For treatment installed upstream of detention or retention, the water quality design flow rate is the peak 15-minute water quality treatment design flow rate as calculated using the latest version of the Western Washington Hydrology Model or other Ecology- approved continuous runoff model.  Eastern Washington: For treatment installed upstream of detention or retention, the water quality design flow rate is the peak 15-minute water quality treatment design flow rate as calculated using one of the three methods described in Chapter 2.2.5 of the Stormwater Management Manual for Eastern Washington (SWMMEW) or local manual.  Entire State: For treatment installed downstream of detention, the water quality treatment design flow rate is the full 2-year release rate of the detention facility. 3. These use level designations have no expiration date but may be amended or revoked by Ecology, and are subject to the conditions specified below. Ecology’s Conditions of Use Applicants shall comply with the following conditions: 1) Design, assemble, install, operate, and maintain the MWS – Linear Modular Wetland Stormwater Treatment System units, in accordance with Modular Wetland Systems, Inc. applicable manuals and documents and the Ecology Decision. 2) Each site plan must undergo Modular Wetland Systems, Inc. review and approval before site installation. This ensures that site grading and slope are appropriate for use of a MWS – Linear Modular Wetland Stormwater Treatment System unit. 3) MSW – Linear Modular Wetland Stormwater Treatment System media shall conform to the specifications submitted to and approved by Ecology. 4) The applicant tested the MWS – Linear Modular Wetland Stormwater Treatment System with an external bypass weir. This weir limited the depth of water flowing through the media, and therefore the active treatment area, to below the root zone of the plants. This GULD applies to MWS – Linear Modular Wetland Stormwater Treatment Systems whether plants are included in the final product or not. 5) Maintenance: The required maintenance interval for stormwater treatment devices is often dependent upon the degree of pollutant loading from a particular drainage basin. Therefore, Ecology does not endorse or recommend a “one size fits all” maintenance cycle for a particular model/size of stormwater treatment technology.  Typically, Modular Wetland Systems, Inc. designs MWS – Linear Modular Wetland systems for a target prefilter media life of 6 to 12 months.  Indications of the need for maintenance include effluent flow decreasing to below the design flow rate or decrease in treatment below required levels.  Owners/operators must inspect MWS – Linear Modular Wetland systems for a minimum of twelve months from the start of post-construction operation to determine site-specific maintenance schedules and requirements. You must conduct inspections monthly during the wet season, and every other month during the dry season (According to the SWMMWW, the wet season in western Washington is October 1 to April 30. According to the SWMMEW, the wet season in eastern Washington is October 1 to June 30). After the first year of operation, owners/operators must conduct inspections based on the findings during the first year of inspections.  Conduct inspections by qualified personnel, follow manufacturer’s guidelines, and use methods capable fo determining either a decrease in treated effluent flowrate and/or a decrease in pollutant removal ability.  When inspections are performed, the following findings typically serve as maintenance triggers:  Standing water remains in the vault between rain events, or  Bypass occurs during storms smaller than the design storm.  If excessive floatables (trash and debris) are present (but no standing water or excessive sedimentation), perform a minor maintenance consisting of gross solids removal, not prefilter media replacement.  Additional data collection will be used to create a correlation between pretreatment chamber sediment depth and pre-filter clogging (see Issues to be Addressed by the Company section below) 6) Discharges from the MWS – Linear Modular Wetland Stormwater Treatment System units shall not cause or contribute to water quality standards violations in receiving waters. Applicant: Modular Wetland Systems, Inc. Applicant’s Address: 5796 Armada Drive, Suite 250 Carlsbad, CA 92008 Application Documents: Original Application for Conditional Use Level Designation, Modular Wetland System, Linear Stormwater Filtration System Modular Wetland Systems, Inc., January 2011 Quality Assurance Project Plan: Modular Wetland System – Linear Treatment System Performance Monitoring Project, draft, January 2011 Revised Application for Conditional Use Level Designation, Modular Wetland System, Linear Stormwater Filtration System Modular Wetland Systems, Inc., May 2011 Memorandum: Modular Wetland System-Linear GULD Application Supplementary Data, April 2014 Technical Evaluation Report: Modular Wetland System Stormwater Treatment System Performance Monitoring, April 2014 Applicant’s Use Level Request:  General Use Level Designation as a Basic, Enhanced, and Phosphorus treatment device in accordance with Ecology’s Guidance for Evaluating Emerging Stormwater Treatment Technologies Technology Assessment Protocol – Ecology (TAPE) January 2011 Revision. Applicant’s Performance Claims:  The MWS – Linear Modular wetland is capable of removing a minimum of 80-percent of TSS from stormwater with influent concentrations between 100 and 200 mg/L.  The MWS – Linear Modular wetland is capable of removing a minimum of 50-percent of total phosphorus from stormwater with influent concentrations between 0.1 and 0.5 mg/L.  The MWS – Linear Modular wetland is capable of removing a minimum 30-percent of dissolved copper from stormwater with influent concentrations between 0.005 and 0.020 mg/L.  The MWS – Linear Modular wetland is capable of removing a minimum 60-percent of dissolved zinc from stormwater with influent concentrations between 0.02 and 0.30 mg/L. Ecology’s Recommendations:  Modular Wetland System, Inc. has shown Ecology, through laboratory and field- testing, that the MWS – Linear Modular Wetland Stormwater Treatment System filter system is capable of attaining Ecology’s Basic, Phosphorus, and Enhanced treatment goals. Findings of Fact: Laboratory Testing The MWS-Linear Modular wetland has the:  Capability to remove 99 percent of total suspended solids (using Sil-Co-Sil 106) in a quarter-scale model with influent concentrations of 270 mg/L.  Capability to remove 91 percent of total suspended solids (using Sil-Co-Sil 106) in laboratory conditions with influent concentrations of 84.6 mg/L at a flow rate of 3.0 gpm per square foot of media.  Capability to remove 93 percent of dissolved Copper in a quarter-scale model with influent concentrations of 0.757 mg/L.  Capability to remove 79 percent of dissolved Copper in laboratory conditions with influent concentrations of 0.567 mg/L at a flow rate of 3.0 gpm per square foot of media.  Capability to remove 80.5-percent of dissolved Zinc in a quarter-scale model with influent concentrations of 0.95 mg/L at a flow rate of 3.0 gpm per square foot of media.  Capability to remove 78-percent of dissolved Zinc in laboratory conditions with influent concentrations of 0.75 mg/L at a flow rate of 3.0 gpm per square foot of media. Field Testing  Modular Wetland Systems, Inc. conducted monitoring of an MWS-Linear (Model # MWS-L-4-13) from April 2012 through May 2013, at a transportation maintenance facility in Portland, Oregon. The manufacturer collected flow-weighted composite samples of the system’s influent and effluent during 28 separate storm events. The system treated approximately 75 percent of the runoff from 53.5 inches of rainfall during the monitoring period. The applicant sized the system at 1 gpm/sq ft. (wetland media) and 3gpm/sq ft. (prefilter).  Influent TSS concentrations for qualifying sampled storm events ranged from 20 to 339 mg/L. Average TSS removal for influent concentrations greater than 100 mg/L (n=7) averaged 85 percent. For influent concentrations in the range of 20-100 mg/L (n=18), the upper 95 percent confidence interval about the mean effluent concentration was 12.8 mg/L.  Total phosphorus removal for 17 events with influent TP concentrations in the range of 0.1 to 0.5 mg/L averaged 65 percent. A bootstrap estimate of the lower 95 percent confidence limit (LCL95) of the mean total phosphorus reduction was 58 percent.  The lower 95 percent confidence limit of the mean percent removal was 60.5 percent for dissolved zinc for influent concentrations in the range of 0.02 to 0.3 mg/L (n=11). The lower 95 percent confidence limit of the mean percent removal was 32.5 percent for dissolved copper for influent concentrations in the range of 0.005 to 0.02 mg/L (n=14) at flow rates up to 28 gpm (design flow rate 41 gpm). Laboratory test data augmented the data set, showing dissolved copper removal at the design flow rate of 41 gpm (93 percent reduction in influent dissolved copper of 0.757 mg/L). Issues to be addressed by the Company: 1. Modular Wetland Systems, Inc. should collect maintenance and inspection data for the first year on all installations in the Northwest in order to assess standard maintenance requirements for various land uses in the region. Modular Wetland Systems, Inc. should use these data to establish required maintenance cycles. 2. Modular Wetland Systems, Inc. should collect pre-treatment chamber sediment depth data for the first year of operation for all installations in the Northwest. Modular Wetland Systems, Inc. will use these data to create a correlation between sediment depth and pre-filter clogging. Technology Description: Download at http://www.modularwetlands.com/ Contact Information: Applicant: Zach Kent BioClean A Forterra Company 5796 Armada Drive, Suite 250 Carlsbad, CA 92008 zach.kent@forterrabp.com Applicant website: http://www.modularwetlands.com/ Ecology web link: http://www.ecy.wa.gov/programs/wg/stormwater/newtech/index.html Ecology: Douglas C. Howie, P.E. Department of Ecology Water Quality Program (360) 870-0983 douglas.howie@ecy.wa.gov Revision History Date Revision June 2011 Original use-level-designation document September 2012 Revised dates for TER and expiration January 2013 Modified Design Storm Description, added Revision Table, added maintenance discussion, modified format in accordance with Ecology standard December 2013 Updated name of Applicant April 2014 Approved GULD designation for Basic, Phosphorus, and Enhanced treatment December 2015 Updated GULD to document the acceptance of MWS – Linear Modular Wetland installations with or without the inclusion of plants July 2017 Revised Manufacturer Contact Information (name, address, and email) December 2019 Revised Manufacturer Contact Address July 2021 Added additional prefilter sized at 33 inches August 2021 Changed “Prefilter” to “Prefilter box” 5796 Armada Dr. Suite 250, Carlsbad, Ca 92008 (469) 458-7973 • Fax (760) 433-3176 www.biocleanenvironmental com Date: 08/17/21 Subject: 13734– New Elementary #16 - Renton, Wa To Whom It May Concern, The MWS Linear will be sized in accordance with the TAPE GULD approval for the Modular Wetland System. The system is sized at a loading rate of (less than or equal to) 1.0 gpm/ sq ft, where the pre-filter cartridges are sized at a loading rate of less than 2.1 gpm/sq ft. Design, sizing, and loading have been reviewed and approved by a Modular Wetland Representative and is ready for final approval. Shown below are the calculations for this Project: MWS-L-4-6.33-V-UG • Required Treatment Flow Rate = 0.02502 cfs • MWS-Linear-4-6.33 Treatment Capacity Provided = 0.02502 cfs or 11.23 gpm at 2.0’ HGL • Pre-filter Cartridge = 1 half size cartridges • Surface Area per Cartridge = 12.8 sq ft • Loading rate (Pre-Filter Cartridge) = 0.9 gpm/sq ft • MWS Wetland Surface Area = 18.60 sf • Loading Rate (Wetland Media) = 0.6 gpm/sf MWS-L-4-8-V-UG • Required Treatment Flow Rate = 0.06754 cfs • MWS-Linear-4-8 Treatment Capacity Provided = 0.06754 cfs or 30.31 gpm at 2.0’ HGL • Pre-filter Cartridge = 1 full size cartridges • Surface Area per Cartridge = 25.6 sq ft • Loading rate (Pre-Filter Cartridge) = 1.2 gpm/sq ft • MWS Wetland Surface Area = 29.60 sf • Loading Rate (Wetland Media) = 1.0 gpm/sf If you have any questions, please feel free to contact us at your convenience Sincerely, Jim Chiang, E.I.T. Renton ES 16 Conveyance Analysis Spreadsheet Gravity Discharge Pipe Run Description Size Mannings N Plan Slope Qfull Tributary Basins Total Tributary Area Tributary Impervious Tributary Grass Qtrib, 25-year (MGS Flood, 15 min) % Full (25-year) Qtrib, 100-year (MGS Flood, 15 min) % Full (100-year) (inches)(ft/ft)(cfs)(ac)(ac)(ac)(cfs)(cfs) 1 South Basin - Pipe Outlet to Point of Discharge 12 0.011 0.005 2.99 South Basin - Tributary to Detention 1A and 1B (Assumed Overflow Condition) 0.663 0.562 0.101 0.44 15%0.66 22% 2 South Basin - Pipe Outlet From Detention 1A 8 0.011 0.005 1.01 South Basin - Tributary to Detention 1A (Assumed Overflow Condition)0.285 0.285 0.000 0.20 20%0.30 30% 3 South Basin - Pipe Outlet From Detention 1B 8 0.011 0.005 1.01 South Basin - Tributary to Detention 1B (Assumed Overflow Condition)0.378 0.277 0.101 0.24 24%0.36 35% 4 North Basin - Pipe Outlet to Point of Discharge 15 0.011 0.008 6.85 North Basin - Tributary to Detention 2 (Assumed Overflow Condition)2.462 1.808 0.654 3.05 45%4.52 66% ————————————————————————————————— MGS FLOOD PROJECT REPORT – SOUTH BASIN OUTLET TO POINT OF DISCHARGE CONVEYANCE Program Version: MGSFlood 4.57 Program License Number: 201410003 Project Simulation Performed on: 03/04/2022 11:54 AM Report Generation Date: 03/04/2022 11:54 AM ————————————————————————————————— Input File Name: South Basin - Detention_Combined Conveyance.fld Project Name: Renton ES #16 Analysis Title: WQ/Detention - South Basin Comments: ———————————————— PRECIPITATION INPUT ———————————————— Computational Time Step (Minutes): 15 Extended Precipitation Time Series Selected Climatic Region Number: 16 Full Period of Record Available used for Routing Precipitation Station : 96004405 Puget East 44 in_5min 10/01/1939-10/01/2097 Evaporation Station : 961044 Puget East 44 in MAP Evaporation Scale Factor : 0.750 HSPF Parameter Region Number: 3 HSPF Parameter Region Name : USGS Default ********** Default HSPF Parameters Used (Not Modified by User) *************** ********************** WATERSHED DEFINITION *********************** Predevelopment/Post Development Tributary Area Summary Predeveloped Post Developed Total Subbasin Area (acres) 0.663 0.663 Area of Links that Include Precip/Evap (acres) 0.000 0.000 Total (acres) 0.663 0.663 ----------------------SCENARIO: PREDEVELOPED Number of Subbasins: 2 ---------- Subbasin : Basin to Det 1A ---------- -------Area (Acres) -------- Till Forest 0.285 ---------------------------------------------- Subbasin Total 0.285 ---------- Subbasin : Basin to Det 1B ---------- -------Area (Acres) -------- Till Forest 0.378 ---------------------------------------------- Subbasin Total 0.378 ----------------------SCENARIO: POSTDEVELOPED Number of Subbasins: 2 ---------- Subbasin : To Detention 1 ---------- -------Area (Acres) -------- Impervious 0.285 ---------------------------------------------- Subbasin Total 0.285 ---------- Subbasin : To Detention 2 ---------- -------Area (Acres) -------- Till Grass 0.101 Impervious 0.277 ---------------------------------------------- Subbasin Total 0.378 ************************* LINK DATA ******************************* ----------------------SCENARIO: PREDEVELOPED Number of Links: 1 ------------------------------------------ Link Name: South POC Link Type: Copy Downstream Link: None ************************* LINK DATA ******************************* ----------------------SCENARIO: POSTDEVELOPED Number of Links: 1 ------------------------------------------ Link Name: South POC Link Type: Copy Downstream Link: None **********************FLOOD FREQUENCY AND DURATION STATISTICS******************* ----------------------SCENARIO: PREDEVELOPED Number of Subbasins: 2 Number of Links: 1 ----------------------SCENARIO: POSTDEVELOPED Number of Subbasins: 2 Number of Links: 1 ***********Groundwater Recharge Summary ************* Recharge is computed as input to Perlnd Groundwater Plus Infiltration in Structures Total Predeveloped Recharge During Simulation Model Element Recharge Amount (ac-ft) ----------------------------------------------------------------------------------------------- Subbasin: Basin to Det 1A 54.218 Subbasin: Basin to Det 1B 71.911 Link: South POC 0.000 _____________________________________ Total: 126.129 Total Post Developed Recharge During Simulation Model Element Recharge Amount (ac-ft) ----------------------------------------------------------------------------------------------- Subbasin: To Detention 1 0.000 Subbasin: To Detention 2 13.008 Link: South POC 0.000 _____________________________________ Total: 13.008 Total Predevelopment Recharge is Greater than Post Developed Average Recharge Per Year, (Number of Years= 158) Predeveloped: 0.798 ac-ft/year, Post Developed: 0.082 ac-ft/year ***********Water Quality Facility Data ************* ----------------------SCENARIO: PREDEVELOPED Number of Links: 1 ********** Link: South POC ********** 2-Year Discharge Rate : 0.017 cfs 15-Minute Timestep, Water Quality Treatment Design Discharge On-line Design Discharge Rate (91% Exceedance): 0.01 cfs Off-line Design Discharge Rate (91% Exceedance): 0.01 cfs Infiltration/Filtration Statistics-------------------- Inflow Volume (ac-ft): 80.70 Inflow Volume Including PPT-Evap (ac-ft): 80.70 Total Runoff Infiltrated (ac-ft): 0.00, 0.00% Total Runoff Filtered (ac-ft): 0.00, 0.00% Primary Outflow To Downstream System (ac-ft): 80.70 Secondary Outflow To Downstream System (ac-ft): 0.00 Volume Lost to ET (ac-ft): 0.00 Percent Treated (Infiltrated+Filtered+ET)/Total Volume: 0.00% ----------------------SCENARIO: POSTDEVELOPED Number of Links: 1 ********** Link: South POC ********** 2-Year Discharge Rate : 0.231 cfs 15-Minute Timestep, Water Quality Treatment Design Discharge On-line Design Discharge Rate (91% Exceedance): 0.09 cfs Off-line Design Discharge Rate (91% Exceedance): 0.05 cfs Infiltration/Filtration Statistics-------------------- Inflow Volume (ac-ft): 306.91 Inflow Volume Including PPT-Evap (ac-ft): 306.91 Total Runoff Infiltrated (ac-ft): 0.00, 0.00% Total Runoff Filtered (ac-ft): 0.00, 0.00% Primary Outflow To Downstream System (ac-ft): 306.91 Secondary Outflow To Downstream System (ac-ft): 0.00 Volume Lost to ET (ac-ft): 0.00 Percent Treated (Infiltrated+Filtered+ET)/Total Volume: 0.00% ***********Compliance Point Results ************* Scenario Predeveloped Compliance Link: South POC Scenario Postdeveloped Compliance Link: South POC *** Point of Compliance Flow Frequency Data *** Recurrence Interval Computed Using Gringorten Plotting Position Predevelopment Runoff Postdevelopment Runoff Tr (Years) Discharge (cfs) Tr (Years) Discharge (cfs) ---------------------------------------------------------------------------------------------------------------------- 2-Year 1.705E-02 2-Year 0.231 5-Year 2.733E-02 5-Year 0.297 10-Year 3.564E-02 10-Year 0.358 25-Year 4.899E-02 25-Year 0.444 50-Year 6.159E-02 50-Year 0.534 100-Year 6.535E-02 100-Year 0.657 200-Year 0.104 200-Year 0.682 500-Year 0.157 500-Year 0.713 ** Record too Short to Compute Peak Discharge for These Recurrence Intervals ————————————————————————————————— MGS FLOOD PROJECT REPORT – DETENTION 1A CONVEYANCE ANALYSIS Program Version: MGSFlood 4.57 Program License Number: 201410003 Project Simulation Performed on: 03/04/2022 11:55 AM Report Generation Date: 03/04/2022 11:55 AM ————————————————————————————————— Input File Name: South Basin - Detention 1A Conveyance.fld Project Name: Renton ES #16 Analysis Title: WQ/Detention - South Basin Comments: ———————————————— PRECIPITATION INPUT ———————————————— Computational Time Step (Minutes): 15 Extended Precipitation Time Series Selected Climatic Region Number: 16 Full Period of Record Available used for Routing Precipitation Station : 96004405 Puget East 44 in_5min 10/01/1939-10/01/2097 Evaporation Station : 961044 Puget East 44 in MAP Evaporation Scale Factor : 0.750 HSPF Parameter Region Number: 3 HSPF Parameter Region Name : USGS Default ********** Default HSPF Parameters Used (Not Modified by User) *************** ********************** WATERSHED DEFINITION *********************** Predevelopment/Post Development Tributary Area Summary Predeveloped Post Developed Total Subbasin Area (acres) 0.285 0.285 Area of Links that Include Precip/Evap (acres) 0.000 0.000 Total (acres) 0.285 0.285 ----------------------SCENARIO: PREDEVELOPED Number of Subbasins: 1 ---------- Subbasin : Basin to Det 1A ---------- -------Area (Acres) -------- Till Forest 0.285 ---------------------------------------------- Subbasin Total 0.285 ----------------------SCENARIO: POSTDEVELOPED Number of Subbasins: 1 ---------- Subbasin : To Detention 1A ---------- -------Area (Acres) -------- Impervious 0.285 ---------------------------------------------- Subbasin Total 0.285 ************************* LINK DATA ******************************* ----------------------SCENARIO: PREDEVELOPED Number of Links: 1 ------------------------------------------ Link Name: South POC Link Type: Copy Downstream Link: None ************************* LINK DATA ******************************* ----------------------SCENARIO: POSTDEVELOPED Number of Links: 1 ------------------------------------------ Link Name: South POC Link Type: Copy Downstream Link: None **********************FLOOD FREQUENCY AND DURATION STATISTICS******************* ----------------------SCENARIO: PREDEVELOPED Number of Subbasins: 1 Number of Links: 1 ----------------------SCENARIO: POSTDEVELOPED Number of Subbasins: 1 Number of Links: 1 ***********Groundwater Recharge Summary ************* Recharge is computed as input to Perlnd Groundwater Plus Infiltration in Structures Total Predeveloped Recharge During Simulation Model Element Recharge Amount (ac-ft) ----------------------------------------------------------------------------------------------- Subbasin: Basin to Det 1A 54.218 Link: South POC 0.000 _____________________________________ Total: 54.218 Total Post Developed Recharge During Simulation Model Element Recharge Amount (ac-ft) ----------------------------------------------------------------------------------------------- Subbasin: To Detention 1A 0.000 Link: South POC 0.000 _____________________________________ Total: 0.000 Total Predevelopment Recharge is Greater than Post Developed Average Recharge Per Year, (Number of Years= 158) Predeveloped: 0.343 ac-ft/year, Post Developed: 0.000 ac-ft/year ***********Water Quality Facility Data ************* ----------------------SCENARIO: PREDEVELOPED Number of Links: 1 ********** Link: South POC ********** 2-Year Discharge Rate : 0.007 cfs 15-Minute Timestep, Water Quality Treatment Design Discharge On-line Design Discharge Rate (91% Exceedance): 0.01 cfs Off-line Design Discharge Rate (91% Exceedance): 0.00 cfs Infiltration/Filtration Statistics-------------------- Inflow Volume (ac-ft): 34.69 Inflow Volume Including PPT-Evap (ac-ft): 34.69 Total Runoff Infiltrated (ac-ft): 0.00, 0.00% Total Runoff Filtered (ac-ft): 0.00, 0.00% Primary Outflow To Downstream System (ac-ft): 34.69 Secondary Outflow To Downstream System (ac-ft): 0.00 Volume Lost to ET (ac-ft): 0.00 Percent Treated (Infiltrated+Filtered+ET)/Total Volume: 0.00% ----------------------SCENARIO: POSTDEVELOPED Number of Links: 1 ********** Link: South POC ********** 2-Year Discharge Rate : 0.111 cfs 15-Minute Timestep, Water Quality Treatment Design Discharge On-line Design Discharge Rate (91% Exceedance): 0.04 cfs Off-line Design Discharge Rate (91% Exceedance): 0.03 cfs Infiltration/Filtration Statistics-------------------- Inflow Volume (ac-ft): 143.06 Inflow Volume Including PPT-Evap (ac-ft): 143.06 Total Runoff Infiltrated (ac-ft): 0.00, 0.00% Total Runoff Filtered (ac-ft): 0.00, 0.00% Primary Outflow To Downstream System (ac-ft): 143.06 Secondary Outflow To Downstream System (ac-ft): 0.00 Volume Lost to ET (ac-ft): 0.00 Percent Treated (Infiltrated+Filtered+ET)/Total Volume: 0.00% ***********Compliance Point Results ************* Scenario Predeveloped Compliance Link: South POC Scenario Postdeveloped Compliance Link: South POC *** Point of Compliance Flow Frequency Data *** Recurrence Interval Computed Using Gringorten Plotting Position Predevelopment Runoff Postdevelopment Runoff Tr (Years) Discharge (cfs) Tr (Years) Discharge (cfs) ---------------------------------------------------------------------------------------------------------------------- 2-Year 7.331E-03 2-Year 0.111 5-Year 1.175E-02 5-Year 0.145 10-Year 1.532E-02 10-Year 0.168 25-Year 2.106E-02 25-Year 0.203 50-Year 2.648E-02 50-Year 0.246 100-Year 2.809E-02 100-Year 0.301 200-Year 4.488E-02 200-Year 0.315 500-Year 6.747E-02 500-Year 0.333 ** Record too Short to Compute Peak Discharge for These Recurrence Intervals ————————————————————————————————— MGS FLOOD PROJECT REPORT– DETENTION 1B CONVEYANCE ANALYSIS Program Version: MGSFlood 4.57 Program License Number: 201410003 Project Simulation Performed on: 03/04/2022 11:57 AM Report Generation Date: 03/04/2022 11:58 AM ————————————————————————————————— Input File Name: South Basin - Detention 1B Conveyance.fld Project Name: Renton ES #16 Analysis Title: WQ/Detention - South Basin Comments: ———————————————— PRECIPITATION INPUT ———————————————— Computational Time Step (Minutes): 15 Extended Precipitation Time Series Selected Climatic Region Number: 16 Full Period of Record Available used for Routing Precipitation Station : 96004405 Puget East 44 in_5min 10/01/1939-10/01/2097 Evaporation Station : 961044 Puget East 44 in MAP Evaporation Scale Factor : 0.750 HSPF Parameter Region Number: 3 HSPF Parameter Region Name : USGS Default ********** Default HSPF Parameters Used (Not Modified by User) *************** ********************** WATERSHED DEFINITION *********************** Predevelopment/Post Development Tributary Area Summary Predeveloped Post Developed Total Subbasin Area (acres) 0.378 0.378 Area of Links that Include Precip/Evap (acres) 0.000 0.000 Total (acres) 0.378 0.378 ----------------------SCENARIO: PREDEVELOPED Number of Subbasins: 1 ---------- Subbasin : Basin to Det 1B ---------- -------Area (Acres) -------- Till Forest 0.378 ---------------------------------------------- Subbasin Total 0.378 ----------------------SCENARIO: POSTDEVELOPED Number of Subbasins: 1 ---------- Subbasin : To Detention 1B ---------- -------Area (Acres) -------- Till Grass 0.101 Impervious 0.277 ---------------------------------------------- Subbasin Total 0.378 ************************* LINK DATA ******************************* ----------------------SCENARIO: PREDEVELOPED Number of Links: 1 ------------------------------------------ Link Name: South POC Link Type: Copy Downstream Link: None ************************* LINK DATA ******************************* ----------------------SCENARIO: POSTDEVELOPED Number of Links: 1 ------------------------------------------ Link Name: South POC Link Type: Copy Downstream Link: None **********************FLOOD FREQUENCY AND DURATION STATISTICS******************* ----------------------SCENARIO: PREDEVELOPED Number of Subbasins: 1 Number of Links: 1 ----------------------SCENARIO: POSTDEVELOPED Number of Subbasins: 1 Number of Links: 1 ***********Groundwater Recharge Summary ************* Recharge is computed as input to Perlnd Groundwater Plus Infiltration in Structures Total Predeveloped Recharge During Simulation Model Element Recharge Amount (ac-ft) ----------------------------------------------------------------------------------------------- Subbasin: Basin to Det 1B 71.911 Link: South POC 0.000 _____________________________________ Total: 71.911 Total Post Developed Recharge During Simulation Model Element Recharge Amount (ac-ft) ----------------------------------------------------------------------------------------------- Subbasin: To Detention 1B 13.008 Link: South POC 0.000 _____________________________________ Total: 13.008 Total Predevelopment Recharge is Greater than Post Developed Average Recharge Per Year, (Number of Years= 158) Predeveloped: 0.455 ac-ft/year, Post Developed: 0.082 ac-ft/year ***********Water Quality Facility Data ************* ----------------------SCENARIO: PREDEVELOPED Number of Links: 1 ********** Link: South POC ********** 2-Year Discharge Rate : 0.010 cfs 15-Minute Timestep, Water Quality Treatment Design Discharge On-line Design Discharge Rate (91% Exceedance): 0.01 cfs Off-line Design Discharge Rate (91% Exceedance): 0.00 cfs Infiltration/Filtration Statistics-------------------- Inflow Volume (ac-ft): 46.01 Inflow Volume Including PPT-Evap (ac-ft): 46.01 Total Runoff Infiltrated (ac-ft): 0.00, 0.00% Total Runoff Filtered (ac-ft): 0.00, 0.00% Primary Outflow To Downstream System (ac-ft): 46.01 Secondary Outflow To Downstream System (ac-ft): 0.00 Volume Lost to ET (ac-ft): 0.00 Percent Treated (Infiltrated+Filtered+ET)/Total Volume: 0.00% ----------------------SCENARIO: POSTDEVELOPED Number of Links: 1 ********** Link: South POC ********** 2-Year Discharge Rate : 0.119 cfs 15-Minute Timestep, Water Quality Treatment Design Discharge On-line Design Discharge Rate (91% Exceedance): 0.04 cfs Off-line Design Discharge Rate (91% Exceedance): 0.02 cfs Infiltration/Filtration Statistics-------------------- Inflow Volume (ac-ft): 163.85 Inflow Volume Including PPT-Evap (ac-ft): 163.85 Total Runoff Infiltrated (ac-ft): 0.00, 0.00% Total Runoff Filtered (ac-ft): 0.00, 0.00% Primary Outflow To Downstream System (ac-ft): 163.85 Secondary Outflow To Downstream System (ac-ft): 0.00 Volume Lost to ET (ac-ft): 0.00 Percent Treated (Infiltrated+Filtered+ET)/Total Volume: 0.00% ***********Compliance Point Results ************* Scenario Predeveloped Compliance Link: South POC Scenario Postdeveloped Compliance Link: South POC *** Point of Compliance Flow Frequency Data *** Recurrence Interval Computed Using Gringorten Plotting Position Predevelopment Runoff Postdevelopment Runoff Tr (Years) Discharge (cfs) Tr (Years) Discharge (cfs) ---------------------------------------------------------------------------------------------------------------------- 2-Year 9.723E-03 2-Year 0.119 5-Year 1.558E-02 5-Year 0.157 10-Year 2.032E-02 10-Year 0.187 25-Year 2.793E-02 25-Year 0.239 50-Year 3.512E-02 50-Year 0.289 100-Year 3.726E-02 100-Year 0.356 200-Year 5.952E-02 200-Year 0.367 500-Year 8.949E-02 500-Year 0.380 ** Record too Short to Compute Peak Discharge for These Recurrence Intervals ————————————————————————————————— MGS FLOOD PROJECT REPORT – NORTH BASIN Conveyance Program Version: MGSFlood 4.57 Program License Number: 201410003 Project Simulation Performed on: 12/17/2021 11:49 AM Report Generation Date: 12/17/2021 11:49 AM ————————————————————————————————— Input File Name: North Basin - Conveyance.fld Project Name: Renton ES #16 Analysis Title: Conveyance - North Basin Comments: ———————————————— PRECIPITATION INPUT ———————————————— Computational Time Step (Minutes): 15 Extended Precipitation Time Series Selected Climatic Region Number: 16 Full Period of Record Available used for Routing Precipitation Station : 96004405 Puget East 44 in_5min 10/01/1939-10/01/2097 Evaporation Station : 961044 Puget East 44 in MAP Evaporation Scale Factor : 0.750 HSPF Parameter Region Number: 3 HSPF Parameter Region Name : USGS Default ********** Default HSPF Parameters Used (Not Modified by User) *************** ********************** WATERSHED DEFINITION *********************** Predevelopment/Post Development Tributary Area Summary Predeveloped Post Developed Total Subbasin Area (acres) 4.576 4.576 Area of Links that Include Precip/Evap (acres) 0.000 0.000 Total (acres) 4.576 4.576 ----------------------SCENARIO: PREDEVELOPED Number of Subbasins: 1 ---------- Subbasin : North Basin ---------- -------Area (Acres) -------- Till Forest 4.120 Till Grass 0.456 ---------------------------------------------- Subbasin Total 4.576 ----------------------SCENARIO: POSTDEVELOPED Number of Subbasins: 1 ---------- Subbasin : To Detention/WQ ---------- -------Area (Acres) -------- Till Grass 0.735 Impervious 3.841 ---------------------------------------------- Subbasin Total 4.576 ************************* LINK DATA ******************************* ----------------------SCENARIO: PREDEVELOPED Number of Links: 0 ************************* LINK DATA ******************************* ----------------------SCENARIO: POSTDEVELOPED Number of Links: 1 ------------------------------------------ Link Name: POC Link Type: Copy Downstream Link: None **********************FLOOD FREQUENCY AND DURATION STATISTICS******************* ----------------------SCENARIO: PREDEVELOPED Number of Subbasins: 1 Number of Links: 0 ----------------------SCENARIO: POSTDEVELOPED Number of Subbasins: 1 Number of Links: 1 ***********Groundwater Recharge Summary ************* Recharge is computed as input to Perlnd Groundwater Plus Infiltration in Structures Total Predeveloped Recharge During Simulation Model Element Recharge Amount (ac-ft) ----------------------------------------------------------------------------------------------- Subbasin: North Basin 842.519 _____________________________________ Total: 842.519 Total Post Developed Recharge During Simulation Model Element Recharge Amount (ac-ft) ----------------------------------------------------------------------------------------------- Subbasin: To Detention/WQ 94.665 Link: POC 0.000 _____________________________________ Total: 94.665 Total Predevelopment Recharge is Greater than Post Developed Average Recharge Per Year, (Number of Years= 158) Predeveloped: 5.332 ac-ft/year, Post Developed: 0.599 ac-ft/year ***********Water Quality Facility Data ************* ----------------------SCENARIO: PREDEVELOPED Number of Links: 0 ----------------------SCENARIO: POSTDEVELOPED Number of Links: 1 ********** Link: POC ********** 2-Year Discharge Rate : 1.584 cfs 15-Minute Timestep, Water Quality Treatment Design Discharge On-line Design Discharge Rate (91% Exceedance): 0.59 cfs Off-line Design Discharge Rate (91% Exceedance): 0.33 cfs Infiltration/Filtration Statistics-------------------- Inflow Volume (ac-ft): 2108.59 Inflow Volume Including PPT-Evap (ac-ft): 2108.59 Total Runoff Infiltrated (ac-ft): 0.00, 0.00% Total Runoff Filtered (ac-ft): 0.00, 0.00% Primary Outflow To Downstream System (ac-ft): 2108.59 Secondary Outflow To Downstream System (ac-ft): 0.00 Volume Lost to ET (ac-ft): 0.00 Percent Treated (Infiltrated+Filtered+ET)/Total Volume: 0.00% ***********Compliance Point Results ************* Scenario Predeveloped Compliance Subbasin: North Basin Scenario Postdeveloped Compliance Link: POC *** Point of Compliance Flow Frequency Data *** Recurrence Interval Computed Using Gringorten Plotting Position Predevelopment Runoff Postdevelopment Runoff Tr (Years) Discharge (cfs) Tr (Years) Discharge (cfs) ---------------------------------------------------------------------------------------------------------------------- 2-Year 0.136 2-Year 1.584 5-Year 0.238 5-Year 2.039 10-Year 0.325 10-Year 2.462 25-Year 0.418 25-Year 3.053 50-Year 0.554 50-Year 3.671 100-Year 0.619 100-Year 4.519 200-Year 0.887 200-Year 4.689 500-Year 1.246 500-Year 4.898 ** Record too Short to Compute Peak Discharge for These Recurrence Intervals Sediment Facility Sizing Calculations - South Basin Per the City of Renton Surface Water Design Manual 2017 Section D.2.1.5.1 Project Name:Renton 16 Required Sediment Facility Surface Area (SA): SA =2*Q/Vsed Where:Q =10-year developed flow rate from MGS Flood Vsed =Settling Velocity (0.00096 ft/sec) Calculation:multiplier =2 Q =0.4520 cfs Vsed =0.00096 fps Required SA =941.7 square feet Equivalent Sediment Trap Volume: Length of Top Surface Area =30 feet Width of Top Surface Area =32 feet Surface Area Provided =960 square feet Side Slope =3 (H:1V) Total Depth of Sediment Trap =3.5 feet Bottom Length of Sediment Trap =9 feet Bottom Width of Sediment Trap =11 feet Total pond Volume =1853.25 cubic feet 13862.31 gallons To determine the minimum sediment trap volume, an equivalent sediment trap was sized based upon the required surface area. Sediment Facility Sizing Calculations - North Basin Per the City of Renton Surface Water Design Manual 2017 Section D.2.1.5.1 Project Name:Renton 16 Required Sediment Facility Surface Area (SA): SA =2*Q/Vsed Where:Q =10-year developed flow rate from MGS Flood Vsed =Settling Velocity (0.00096 ft/sec) Calculation:multiplier =2 Q =2.8610 cfs Vsed =0.00096 fps Required SA =5960.4 square feet Equivalent Sediment Trap Volume: Length of Top Surface Area =30 feet Width of Top Surface Area =32 feet Surface Area Provided =960 square feet Side Slope =3 (H:1V) Total Depth of Sediment Trap =3.5 feet Bottom Length of Sediment Trap =9 feet Bottom Width of Sediment Trap =11 feet Total pond Volume =1853.25 cubic feet 13862.31 gallons To determine the minimum sediment trap volume, an equivalent sediment trap was sized based upon the required surface area. Sediment Facility Sizing Calculations - Wetland Basin Per the City of Renton Surface Water Design Manual 2017 Section D.2.1.5.1 Project Name:Renton 16 Required Sediment Facility Surface Area (SA): SA =2*Q/Vsed Where:Q =10-year developed flow rate from MGS Flood Vsed =Settling Velocity (0.00096 ft/sec) Calculation:multiplier =2 Q =0.3910 cfs Vsed =0.00096 fps Required SA =814.6 square feet Equivalent Sediment Trap Volume: Length of Top Surface Area =30 feet Width of Top Surface Area =28 feet Surface Area Provided =840 square feet Side Slope =3 (H:1V) Total Depth of Sediment Trap =3.5 feet Bottom Length of Sediment Trap =9 feet Bottom Width of Sediment Trap =7 feet Total pond Volume =1580.25 cubic feet 11820.27 gallons To determine the minimum sediment trap volume, an equivalent sediment trap was sized based upon the required surface area. ————————————————————————————————— MGS FLOOD PROJECT REPORT–SOUTH BASIN TESC Sizing and Conveyance Program Version: MGSFlood 4.50 Program License Number: 201410003 Project Simulation Performed on: 12/02/2021 5:34 PM Report Generation Date: 12/02/2021 5:34 PM ————————————————————————————————— Input File Name: South Basin - TESC.fld Project Name: Renton ES #16 Analysis Title: TESC - South Basin Comments: ———————————————— PRECIPITATION INPUT ———————————————— Computational Time Step (Minutes): 15 Extended Precipitation Time Series Selected Climatic Region Number: 16 Full Period of Record Available used for Routing Precipitation Station : 96004405 Puget East 44 in_5min 10/01/1939-10/01/2097 Evaporation Station : 961044 Puget East 44 in MAP Evaporation Scale Factor : 0.750 HSPF Parameter Region Number: 1 HSPF Parameter Region Name : USGS Default ********** Default HSPF Parameters Used (Not Modified by User) *************** ********************** WATERSHED DEFINITION *********************** Predevelopment/Post Development Tributary Area Summary Predeveloped Post Developed Total Subbasin Area (acres) 0.988 0.988 Area of Links that Include Precip/Evap (acres) 0.000 0.000 Total (acres) 0.988 0.988 ----------------------SCENARIO: PREDEVELOPED Number of Subbasins: 1 ---------- Subbasin : Pre-dev Basin ---------- -------Area (Acres) -------- Till Grass 0.354 Impervious 0.634 ---------------------------------------------- Subbasin Total 0.988 ----------------------SCENARIO: POSTDEVELOPED Number of Subbasins: 1 ---------- Subbasin : Post-Dev ---------- -------Area (Acres) -------- Till Grass 0.354 Impervious 0.634 ---------------------------------------------- Subbasin Total 0.988 ************************* LINK DATA ******************************* ----------------------SCENARIO: PREDEVELOPED Number of Links: 0 ************************* LINK DATA ******************************* ----------------------SCENARIO: POSTDEVELOPED Number of Links: 0 **********************FLOOD FREQUENCY AND DURATION STATISTICS******************* ----------------------SCENARIO: PREDEVELOPED Number of Subbasins: 1 Number of Links: 0 ----------------------SCENARIO: POSTDEVELOPED Number of Subbasins: 1 Number of Links: 0 ***********Groundwater Recharge Summary ************* Recharge is computed as input to Perlnd Groundwater Plus Infiltration in Structures Total Predeveloped Recharge During Simulation Model Element Recharge Amount (ac-ft) ----------------------------------------------------------------------------------------------- Subbasin: Pre-dev Basin 45.594 _____________________________________ Total: 45.594 Total Post Developed Recharge During Simulation Model Element Recharge Amount (ac-ft) ----------------------------------------------------------------------------------------------- Subbasin: Post-Dev 45.594 _____________________________________ Total: 45.594 Total Predevelopment Recharge Equals Post Developed Average Recharge Per Year, (Number of Years= 158) Predeveloped: 0.289 ac-ft/year, Post Developed: 0.289 ac-ft/year ***********Water Quality Facility Data ************* ----------------------SCENARIO: PREDEVELOPED Number of Links: 0 ----------------------SCENARIO: POSTDEVELOPED Number of Links: 0 ***********Compliance Point Results ************* Scenario Predeveloped Compliance Subbasin: Pre-dev Basin Scenario Postdeveloped Compliance Subbasin: Post-Dev *** Point of Compliance Flow Frequency Data *** Recurrence Interval Computed Using Gringorten Plotting Position Predevelopment Runoff Postdevelopment Runoff Tr (Years) Discharge (cfs) Tr (Years) Discharge (cfs) ---------------------------------------------------------------------------------------------------------------------- 2-Year 0.286 2-Year 0.286 5-Year 0.379 5-Year 0.379 10-Year 0.452 10-Year 0.452 25-Year 0.575 25-Year 0.575 50-Year 0.722 50-Year 0.722 100-Year 0.892 100-Year 0.892 200-Year 0.914 200-Year 0.914 500-Year 0.939 500-Year 0.939 ** Record too Short to Compute Peak Discharge for These Recurrence Intervals ————————————————————————————————— MGS FLOOD PROJECT REPORT – TESC NORTH BASIN Program Version: MGSFlood 4.50 Program License Number: 201410003 Project Simulation Performed on: 12/02/2021 5:48 PM Report Generation Date: 12/02/2021 5:48 PM ————————————————————————————————— Input File Name: North Basin - TESC.fld Project Name: Renton ES #16 Analysis Title: TESC - North Basin Comments: ———————————————— PRECIPITATION INPUT ———————————————— Computational Time Step (Minutes): 15 Extended Precipitation Time Series Selected Climatic Region Number: 16 Full Period of Record Available used for Routing Precipitation Station : 96004405 Puget East 44 in_5min 10/01/1939-10/01/2097 Evaporation Station : 961044 Puget East 44 in MAP Evaporation Scale Factor : 0.750 HSPF Parameter Region Number: 1 HSPF Parameter Region Name : USGS Default ********** Default HSPF Parameters Used (Not Modified by User) *************** ********************** WATERSHED DEFINITION *********************** Predevelopment/Post Development Tributary Area Summary Predeveloped Post Developed Total Subbasin Area (acres) 5.904 5.904 Area of Links that Include Precip/Evap (acres) 0.000 0.000 Total (acres) 5.904 5.904 ----------------------SCENARIO: PREDEVELOPED Number of Subbasins: 1 ---------- Subbasin : Pre-Dev Basin ---------- -------Area (Acres) -------- Till Grass 1.699 Impervious 4.205 ---------------------------------------------- Subbasin Total 5.904 ----------------------SCENARIO: POSTDEVELOPED Number of Subbasins: 1 ---------- Subbasin : Post-Dev Basin ---------- -------Area (Acres) -------- Till Grass 1.699 Impervious 4.205 ---------------------------------------------- Subbasin Total 5.904 ************************* LINK DATA ******************************* ----------------------SCENARIO: PREDEVELOPED Number of Links: 0 ************************* LINK DATA ******************************* ----------------------SCENARIO: POSTDEVELOPED Number of Links: 0 **********************FLOOD FREQUENCY AND DURATION STATISTICS******************* ----------------------SCENARIO: PREDEVELOPED Number of Subbasins: 1 Number of Links: 0 ----------------------SCENARIO: POSTDEVELOPED Number of Subbasins: 1 Number of Links: 0 ***********Groundwater Recharge Summary ************* Recharge is computed as input to Perlnd Groundwater Plus Infiltration in Structures Total Predeveloped Recharge During Simulation Model Element Recharge Amount (ac-ft) ----------------------------------------------------------------------------------------------- Subbasin: Pre-Dev Basin 218.824 _____________________________________ Total: 218.824 Total Post Developed Recharge During Simulation Model Element Recharge Amount (ac-ft) ----------------------------------------------------------------------------------------------- Subbasin: Post-Dev Basin 218.824 _____________________________________ Total: 218.824 Total Predevelopment Recharge Equals Post Developed Average Recharge Per Year, (Number of Years= 158) Predeveloped: 1.385 ac-ft/year, Post Developed: 1.385 ac-ft/year ***********Water Quality Facility Data ************* ----------------------SCENARIO: PREDEVELOPED Number of Links: 0 ----------------------SCENARIO: POSTDEVELOPED Number of Links: 0 ***********Compliance Point Results ************* Scenario Predeveloped Compliance Subbasin: Pre-Dev Basin Scenario Postdeveloped Compliance Subbasin: Post-Dev Basin *** Point of Compliance Flow Frequency Data *** Recurrence Interval Computed Using Gringorten Plotting Position Predevelopment Runoff Postdevelopment Runoff Tr (Years) Discharge (cfs) Tr (Years) Discharge (cfs) ---------------------------------------------------------------------------------------------------------------------- 2-Year 1.825 2-Year 1.825 5-Year 2.413 5-Year 2.413 10-Year 2.861 10-Year 2.861 25-Year 3.668 25-Year 3.668 50-Year 4.463 50-Year 4.463 100-Year 5.507 100-Year 5.507 200-Year 5.671 200-Year 5.671 500-Year 5.864 500-Year 5.864 ** Record too Short to Compute Peak Discharge for These Recurrence Intervals ————————————————————————————————— MGS FLOOD PROJECT REPORT– TESC WETLAND BASIN Program Version: MGSFlood 4.50 Program License Number: 201410003 Project Simulation Performed on: 12/02/2021 5:55 PM Report Generation Date: 12/02/2021 5:55 PM ————————————————————————————————— Input File Name: Wetland Basin TESC.fld Project Name: Renton ES #16 Analysis Title: TESC- Wetland Basin Comments: ———————————————— PRECIPITATION INPUT ———————————————— Computational Time Step (Minutes): 15 Extended Precipitation Time Series Selected Climatic Region Number: 16 Full Period of Record Available used for Routing Precipitation Station : 96004405 Puget East 44 in_5min 10/01/1939-10/01/2097 Evaporation Station : 961044 Puget East 44 in MAP Evaporation Scale Factor : 0.750 HSPF Parameter Region Number: 1 HSPF Parameter Region Name : USGS Default ********** Default HSPF Parameters Used (Not Modified by User) *************** ********************** WATERSHED DEFINITION *********************** Predevelopment/Post Development Tributary Area Summary Predeveloped Post Developed Total Subbasin Area (acres) 1.008 1.008 Area of Links that Include Precip/Evap (acres) 0.000 0.000 Total (acres) 1.008 1.008 ----------------------SCENARIO: PREDEVELOPED Number of Subbasins: 1 ---------- Subbasin : Pre-Dev Basin ---------- -------Area (Acres) -------- Till Grass 0.555 Impervious 0.453 ---------------------------------------------- Subbasin Total 1.008 ----------------------SCENARIO: POSTDEVELOPED Number of Subbasins: 1 ---------- Subbasin : Post-Dev Basin ---------- -------Area (Acres) -------- Till Grass 0.555 Impervious 0.453 ---------------------------------------------- Subbasin Total 1.008 ************************* LINK DATA ******************************* ----------------------SCENARIO: PREDEVELOPED Number of Links: 0 ************************* LINK DATA ******************************* ----------------------SCENARIO: POSTDEVELOPED Number of Links: 0 **********************FLOOD FREQUENCY AND DURATION STATISTICS******************* ----------------------SCENARIO: PREDEVELOPED Number of Subbasins: 1 Number of Links: 0 ----------------------SCENARIO: POSTDEVELOPED Number of Subbasins: 1 Number of Links: 0 ***********Groundwater Recharge Summary ************* Recharge is computed as input to Perlnd Groundwater Plus Infiltration in Structures Total Predeveloped Recharge During Simulation Model Element Recharge Amount (ac-ft) ----------------------------------------------------------------------------------------------- Subbasin: Pre-Dev Basin 71.482 _____________________________________ Total: 71.482 Total Post Developed Recharge During Simulation Model Element Recharge Amount (ac-ft) ----------------------------------------------------------------------------------------------- Subbasin: Post-Dev Basin 71.482 _____________________________________ Total: 71.482 Total Predevelopment Recharge Equals Post Developed Average Recharge Per Year, (Number of Years= 158) Predeveloped: 0.452 ac-ft/year, Post Developed: 0.452 ac-ft/year ***********Water Quality Facility Data ************* ----------------------SCENARIO: PREDEVELOPED Number of Links: 0 ----------------------SCENARIO: POSTDEVELOPED Number of Links: 0 ***********Compliance Point Results ************* Scenario Predeveloped Compliance Subbasin: Pre-Dev Basin Scenario Postdeveloped Compliance Subbasin: Post-Dev Basin *** Point of Compliance Flow Frequency Data *** Recurrence Interval Computed Using Gringorten Plotting Position Predevelopment Runoff Postdevelopment Runoff Tr (Years) Discharge (cfs) Tr (Years) Discharge (cfs) ---------------------------------------------------------------------------------------------------------------------- 2-Year 0.241 2-Year 0.241 5-Year 0.318 5-Year 0.318 10-Year 0.391 10-Year 0.391 25-Year 0.499 25-Year 0.499 50-Year 0.665 50-Year 0.665 100-Year 0.826 100-Year 0.826 200-Year 0.835 200-Year 0.835 500-Year 0.841 500-Year 0.841 ** Record too Short to Compute Peak Discharge for These Recurrence Intervals APPENDIX C Construction Stormwater Pollution Prevention Plan (SWPPP) Narrative Page 1 New Elementary School #16 SWPPP Narrative NEW ELEMENTARY SCHOOL #16 CONSTRUCTION SWPPP NARRATIVE MARCH 4, 2022 The following Preliminary Construction Storm Water Pollution Prevention Plan (SWPPP) Narrative for the new Renton Elementary School #16 supplements the Temporary Erosion and Sediment Control drawings. This narrative and the drawings address the requirements of Section 3.3 of Volume II of the 2014 Washington State Department of Ecology (DOE) Stormwater Management Manual for Western Washington. The project will also require a NPDES permit application (Notice of Intent) for a Construction Stormwater General Permit through the DOE, which will be included with the final permit. 1. CONSTRUCTION STORMWATER POLLUTION PREVENTION ELEMENTS 1) Mark Clearing Limits: Clearing limits will be defined by erosion control components, construction fencing, and/or the existing fence, as shown on the TESC and Site Demolition plan. The actual limits of clearing will most likely be smaller than the limit of work area, but this identifies the maximum extent of the clearing limits. Existing paved area and areas to be cleared will be maintained in an undisturbed condition until required to be impacted. Areas impacted and not anticipated to be covered with final measures shall be stabilized using approved ESC methods. 2) Establish Construction Access: A temporary construction access (BMP C105) will be installed prior to construction. Construction access is provided off of Duvall Avenue N and Chelan Avenue NE. The Contractor shall provide a wheel wash if necessary. 3) Control Flow Rates: Stormwater flow control during construction is anticipated to be mitigated by routing runoff to a temporary sediment storage pond. Refer to the Sediment Pond Sizing calculations and the MGSFlood output included within Appendix B of the project’s Stormwater Technical Information Report. 4) Install Sediment Controls: DOE approved BMPs for sediment controls are shown on the TESC plan. Sediment will be controlled using rock check dams (BMP C207), silt fences (BMP C233), storm drain inlet protection (BMP C220), temporary drainage swales (BMP C200), and the proposed sediment settling traps. Minimum top surface area for sediment trap in South basin is 950 SF. Minimum top surface area for sediment trap in Wetland basin is 840 SF. Minimum top surface area for sediment trap in North basin is 6000 SF. Refer to TESC plans for approximate locations. It is the Contractor’s responsibility to upgrade erosion control as necessary to meet applicable requirements. In order to complete the turbidity monitoring required by the project’s DOE Stormwater General Permit, and in the event that unexpected conditions arise during construction, the Contractor is expected to contract with a third party erosion control monitor to help manage the site and prevent any discharges of turbid water to the downstream system. If turbidity monitoring indicates that the discharged stormwater does not meet the acceptable discharge requirements, the Contractor shall immediately plug the point of discharge and provide additional TESC measures as necessary. The Contractor’s Certified Erosion and Sediment Control Lead (CESCL) will be responsible for coordinating with the third-party monitoring company regarding the required sampling of stormwater discharges from the site as required by the DOE stormwater Page 2 New Elementary School #16 SWPPP Narrative permit. The Contractor’s CESCL will be required to coordinate the required sampling of stormwater discharges from the site at the upstream and downstream turbidity monitoring locations, in accordance with the requirements of the NPDES permit. Since the project site is over 1 acre, turbidity monitoring must be conducted weekly and within 24 hours of a discharge. Water quality testing results will be kept on site for reference and review if requested by the Renton School District, City of Renton, or other agencies. Monthly summary reports (Discharge Monitoring Reports) are required to be submitted to the DOE via the web DMR application. The Contractor will be the permit holder once the Owner completes the Stormwater General Permit Transfer of Coverage at the beginning of construction. The CESCL is also required to perform weekly (at a minimum) inspections of TESC BMPs throughout the site. 5) Stabilize Soils: It is possible that some of the earthwork and grading may occur in wet weather conditions. The site must be stabilized and no soils will be allowed to remain unstabilized for more than two days between October 1st and April 30th. From May 1 through September 30, install cover measures to protect disturbed areas that will remain unworked for seven days or more. By October 8, seed all areas that will remain unworked from October 1 through April 30. Mulch all seeded areas. Exposed slopes will be protected by DOE-approved coverage methods. BMPs including, but not limited to: C101, Preserving Natural Vegetation; C121, Mulching; C123, Plastic Covering; C130, Surface Roughening; C140, Dust Control; and T5.13 Post Construction Soil Amendment will be used to stabilize on-site soils during construction. 6) Protect Slopes: DOE-approved BMPs for slope protection will be utilized during construction. Concentrated discharges shall not be allowed to flow over the top of steep slopes. BMPs including, but not limited to C101, Preserving Natural Vegetation; C121, Mulching; C123, Plastic Covering; C130, Surface Roughening; C140, Dust Control; C200, Interceptor Dike and Swale; C207, Check Dams; and C233, Silt Fence are to be utilized to protect slopes during construction. 7) Protect Drain Inlets: Drainage structures in areas where no work occurs will remain and will be protected; discharge points to the public storm drain main line will also be protected. To prevent discharge of turbid water downstream, all existing catch basins located within the disturbance area and outside of the disturbance area within approximately 300 ft downstream of the site will be protected with storm drain inlet protection (BMP C220). Proposed inlets will also be protected with catch basin inserts, and where feasible, their outlets will be temporarily plugged until the site is stabilized. The Contractor shall remove inlet protection at the end of the project without releasing captured sediment into the storm system. 8) Stabilize Channels and Outlets: DOE-approved BMPs for channel stabilization will be utilized during construction, including, but not limited to C207, Check Dams. 9) Control Pollutants: Temporary protection of the disturbed soils provides the first level of protection for pollution control, and perimeter measures downstream will mitigate the remaining pollutants. The temporary protection of disturbed soils may be mitigated with a temporary sump and pump facility to provide the second level of interception of pollutants. This collection system filters sediments prior to the pump system. The pump system will then route stormwater into the temporary sediment settling traps. All construction debris will be removed from the site. Contractor will be responsible for managing their construction equipment per DOE-approved BMPs. The stabilized Page 3 New Elementary School #16 SWPPP Narrative construction entrance is assumed to be sufficient for the construction period. If something more substantial is required, the Contractor is to coordinate with the Owner’s Representative and the King County inspector. If a truck wheel wash is required, truck wheel wash water and concrete truck washout water shall be collected and discharged to the public sanitary sewer (SS) system. To apply for SS release, contact the local sewer purveyor for authorization. 10) Control De-Watering: The majority of the earthwork on the project will be constructed during the dry season, therefore it is not anticipated that groundwater will be encountered in the excavations for this project. In the event that perched groundwater is encountered during any wet season construction, the Contractor shall route it to the sediment settling trap by pumping it out of the excavation. 11) Maintain BMPs: DOE-approved standard BMP maintenance will be required in accordance with the Erosion and Sedimentation Control Plan and Notes. 12) Manage the Project: All phases of construction will be managed by the Contractor. The site must be stabilized and no soils will be allowed to remain exposed and unworked for more than two days between October 1st and April 30th and for more than seven days between May 1st and September 30th. The Contractor will provide maintenance and monitoring of TESC BMPs. Work of all contractors will be coordinated to minimize the duration of disturbance on the site. The best management practices shown on the TESC plan are minimum requirements. Failure to maintain SWPPP measures in accordance with adopted standards may result in the work being performed at the County’s direction and the costs assessed as a lien against the property where such facilities are located. 13) Protect Low Impact Development BMPs: The project does not propose the use of any Low Impact Development BMPs. 2. PROJECT DESCRIPTION The new Elementary School #16 will be constructed on eleven (11) tax lot parcels and two (2) right-of-way (ROW) parcels with a total area of 11.17 acres. The majority of the parcels contained in the project site previously contained single-family residences which were demolished in January of 2019 and the remaining parcels were undeveloped. The new Renton Elementary School #16 will include an approximately 46,000 square foot school building with a central outdoor courtyard, natural grass playfield, hard and soft surface play areas, an entry plaza, emergency and fire apparatus access loop, a designated bus loop, parking, and a student loading lane. 3. EXISTING SITE CONDITIONS There are two existing wetlands on the site. The City’s Critical Area Map do not identify wetlands on-site; however, a wetland delineation report was performed by The Watershed Company on November 2019 and initially identified three wetlands; Wetlands A, B, C. Further evaluation eliminated Wetland A because it did not meet the criteria for jurisdictional wetlands. Wetland B is located in the northeast portion of the site and Wetland C is along the west property line. The Wetland C, which provides a higher level of function than Wetland B, will be maintained as part of the school development. It is classified as a Type III and requires a 100-ft buffer. Wetland B is considered a Type IV and will be removed and mitigated through a wetland banking system as a part of this project. Page 4 New Elementary School #16 SWPPP Narrative Topographically, the site sits at a high point relative to the surrounding properties. Generally, the site slopes down from the east to the west with elevations ranging from approximately 438 feet in the southeastern portion of the parcel to approximately 409 feet at the existing west wetland area. The site also has areas which slope from south to north, and a smaller area that slopes towards the southwest. The existing topography divides the site drainage into three basins as described in detail below. The site is located within three drainage basins, denoted as the South Basin, the North Basin, and the Wetland Basin. The areas within the South Basin sheet flow to the southwest. The runoff is collected by the existing catch basins along the east side of Chelan Avenue NE and flows into a 12-inch main. The North Basin discharges into Wetland B which flows offsite to the north via a 12-inch storm line and ultimately discharges into a 12-inch storm pipe within NE 12th Street. The Wetland Basin sheet flows to Wetland C and discharges from the site via a 15-inch CMP that conveys flow to the north and eventually connects into a 15-inch storm pipe within NE 12th Street. The storm system from Chelan Avenue NE and NE 12th Street eventually converge and ultimately discharge to May Creek which outlets to Lake Washington. 4. ADJACENT AREAS The project site parcels are bounded by NE 12th Street and a neighboring church property to the north, Duvall Avenue NE to the east, and residential properties to the west and south. NE 10th Street is just beyond the project property to the south. The site is located in Section 10, Township 23 North, Range 5 East, Willamette Meridian. 5. CRITICAL AREAS The City’s Critical Area Map do not identify wetlands on-site; however, a wetland delineation report was performed by The Watershed Company on November 2019 and initially identified three wetlands; Wetlands A, B, C. 6. SOILS A subsurface exploration and geotechnical feasibility study were conducted by Associated Earth Sciences, Inc. (AESI). They prepared their findings in a report dated November 23, 2020. Their field study included fourteen exploration borings across the site. The explorations typically encountered existing fill and recessional outwash sediments underlain by dense, silty Vashon lodgement till sediments. Five exploration borings encountered surficial existing fill to thicknesses of up to approximately 7 feet. Two explorations found shallow Vashon recessional outwash sediments ranging in thickness from approximately 2.5 to 5 feet thick. The northernmost exploration borings terminated in potential lodgement till and advance outwash transition sediments at depths of approximately 20.5 to 21.5 feet. Groundwater was not encountered in any of the explorations completed for this study at the time of exploration. According to AESI’s exploration, the use of potential stormwater infiltration was found to be infeasible due to the extent of dense, silty soils across the site. The existing fill is not a suitable infiltration receptor due to its variable density, silt, and organic content. The recessional outwash found in two of the borings do not have enough vertical depth to support infiltration without adequate separation from the hydraulically restrictive layers. Lodgement till is not a suitable infiltration receptor due to its high silt content. Page 5 New Elementary School #16 SWPPP Narrative 7. POTENTIAL EROSION PROBLEM AREAS The erosion hazard of the site soils is expected to be low. Per the proposed contract documents, the contractor is to provide protection for soils to limit the exposure to erosion. The limitation of disturbance, adequate cover practices, and runoff control are the most effective methods for reduction of turbidity in stormwater runoff. Any runoff that does occur will be directed to the sediment pond. Areas that have not been permanently stabilized will be addressed using DOE-approved BMPs, per the construction documents. 8. CONSTRUCTION PHASING Project phases is not anticipated for this project. 9. CONSTRUCTION SCHEDULE Construction is expected to begin in May 2022 and be complete by September 2023. 10. FINANCIAL/OWNERSHIP RESPONSIBILITIES The property is owned and operated by the Renton School District. The accepted low bidder on the project will be responsible for posting a performance and payment bond with the Renton School District, thus will be the responsible party for any liability associated with erosion and sedimentation impact. 11. ENGINEERING CALCULATIONS A copy of any calculations performed during design of the project and relevant storm drainage modeling discussions is included in the project’s Stormwater Technical Information Report. 12. CERTIFIED EROSION CONTROL SPECIALIST The contractor will name their Certified Erosion Control Specialist and provide contact information at the pre-construction meeting. APPENDIX D Operations and Maintenance Manual An company 2 THE MOST ADVANCED NAME IN WATER MANAGEMENT SOLUTIONS TM ECCENTRICHEADER MANHOLEWITHOVERFLOWWEIR STORMTECHISOLATOR ROW OPTIONAL PRE-TREATMENT OPTIONAL ACCESS STORMTECH CHAMBERS  )( StormTech Maintenance Log Project Name: Location: Stadia Rod Readings Date Fixed point to chamber bottom (1) Fixed point to top of sediment (2) Sediment Depth (1) - (2)Observations / Actions Inspector Modular Wetlands® Linear A Stormwater Biofiltration Solution OPERATION & MAINTENANCE MANUAL Maintenance Guidelines for Modular Wetlands Linear Maintenance Summary o Remove Trash from Screening Device – average maintenance interval is 6 to 12 months. (5 minute average service time). o Remove Sediment from Separation Chamber – average maintenance interval is 12 to 24 months. (10 minute average service time). o Replace Cartridge Filter Media – average maintenance interval 12 to 24 months. (10-15 minute per cartridge average service time). o Replace Drain Down Filter Media – average maintenance interval is 12 to 24 months. (5 minute average service time). o Trim Vegetation – average maintenance interval is 6 to 12 months. (Service time varies). System Diagram Access to screening device, separation chamber and cartridge filter Access to drain down filter Pre-Treatment Chamber Biofiltration Chamber Discharge Chamber Outflow Pipe Inflow Pipe (optional) 5796 Armada Drive #250, Carlsbad, CA | 855.566.3938 | stormwater@forterrabp.com | www.biocleanenvironmental.com Maintenance Procedures Screening Device 1.Remove grate or manhole cover to gain access to the screening device in the Pre- Treatment Chamber. Vault type units do not have screening device. Maintenance can be performed without entry. 2. Remove all pollutants collected by the screening device. Removal can be done manually or with the use of a vacuum truck. The hose of the vacuum truck will not damage the screening device. 3. Screening device can easily be removed from the Pre-Treatment Chamber to gain access to separation chamber and media filters below. Replace grate or manhole cover when completed. Separation Chamber 1. Perform maintenance procedures of screening device listed above before maintaining the separation chamber. 2. With a pressure washer spray down pollutants accumulated on walls and cartridge filters. 3. Vacuum out Separation Chamber and remove all accumulated pollutants. Replace screening device, grate or manhole cover when completed. Cartridge Filters 1.Perform maintenance procedures on screening device and separation chamber before maintaining cartridge filters. 2. Enter separation chamber. 3. Unscrew the two bolts holding the lid on each cartridge filter and remove lid. 4. Remove each of 4 to 8 media cages holding the media in place. 5. Spray down the cartridge filter to remove any accumulated pollutants. 6. Vacuum out old media and accumulated pollutants. 7. Reinstall media cages and fill with new media from manufacturer or outside supplier. Manufacturer will provide specification of media and sources to purchase. 8. Replace the lid and tighten down bolts. Replace screening device, grate or manhole cover when completed. Drain Down Filter 1.Remove hatch or manhole cover over discharge chamber and enter chamber. 2. Unlock and lift drain down filter housing and remove old media block. Replace with new media block. Lower drain down filter housing and lock into place. 3. Exit chamber and replace hatch or manhole cover. Maintenance Notes 1. Following maintenance and/or inspection, it is recommended the maintenance operator prepare a maintenance/inspection record. The record should include any maintenance activities performed, amount and description of debris collected, and condition of the system and its various filter mechanisms. 2. The owner should keep maintenance/inspection record(s) for a minimum of five years from the date of maintenance. These records should be made available to the governing municipality for inspection upon request at any time. 3. Transport all debris, trash, organics and sediments to approved facility for disposal in accordance with local and state requirements. 4. Entry into chambers may require confined space training based on state and local regulations. 5. No fertilizer shall be used in the Biofiltration Chamber. 6. Irrigation should be provided as recommended by manufacturer and/or landscape architect. Amount of irrigation required is dependent on plant species. Some plants may require irrigation. 5796 Armada Drive #250, Carlsbad, CA | 855.566.3938 | stormwater@forterrabp.com | www.biocleanenvironmental.com Maintenance Procedure Illustration Screening Device The screening device is located directly under the manhole or grate over the Pre-Treatment Chamber. It’s mounted directly underneath for easy access and cleaning. Device can be cleaned by hand or with a vacuum truck. Separation Chamber The separation chamber is located directly beneath the screening device. It can be quickly cleaned using a vacuum truck or by hand. A pressure washer is useful to assist in the cleaning process. Cartridge Filters The cartridge filters are located in the Pre-Treatment chamber connected to the wall adjacent to the biofiltration chamber. The cartridges have removable tops to access the individual media filters. Once the cartridge is open media can be easily removed and replaced by hand or a vacuum truck. Drain Down Filter The drain down filter is located in the Discharge Chamber. The drain filter unlocks from the wall mount and hinges up. Remove filter block and replace with new block. Trim Vegetation Vegetation should be maintained in the same manner as surrounding vegetation and trimmed as needed. No fertilizer shall be used on the plants. Irrigation per the recommendation of the manufacturer and or landscape architect. Different types of vegetation requires different amounts of irrigation. 5796 Armada Drive #250, Carlsbad, CA | 855.566.3938 | stormwater@forterrabp.com | www.biocleanenvironmental.com For Office Use Only (city) (Zip Code)(Reviewed By) Owner / Management Company (Date) Contact Phone ( )_ Inspector Name Date / /Time AM / PM Weather Condition Additional Notes Yes Depth: Yes No Modular Wetland System Type (Curb, Grate or UG Vault):Size (22', 14' or etc.): Other Inspection Items: Storm Event in Last 72-hours? No Yes Type of Inspection Routine Follow Up Complaint Storm Office personnel to complete section to the left. Inspection Report Modular Wetlands Linear Is the filter insert (if applicable) at capacity and/or is there an accumulation of debris/trash on the shelf system? Does the cartridge filter media need replacement in pre-treatment chamber and/or discharge chamber? Any signs of improper functioning in the discharge chamber? Note issues in comments section. Chamber: Is the inlet/outlet pipe or drain down pipe damaged or otherwise not functioning properly? Structural Integrity: Working Condition: Is there evidence of illicit discharge or excessive oil, grease, or other automobile fluids entering and clogging the unit? Is there standing water in inappropriate areas after a dry period? Damage to pre-treatment access cover (manhole cover/grate) or cannot be opened using normal lifting pressure? Damage to discharge chamber access cover (manhole cover/grate) or cannot be opened using normal lifting pressure? Does the MWS unit show signs of structural deterioration (cracks in the wall, damage to frame)? Project Name Project Address Inspection Checklist CommentsNo Does the depth of sediment/trash/debris suggest a blockage of the inflow pipe, bypass or cartridge filter? If yes, specify which one in the comments section. Note depth of accumulation in in pre-treatment chamber. Is there a septic or foul odor coming from inside the system? Is there an accumulation of sediment/trash/debris in the wetland media (if applicable)? Is it evident that the plants are alive and healthy (if applicable)? Please note Plant Information below. Sediment / Silt / Clay Trash / Bags / Bottles Green Waste / Leaves / Foliage Waste:Plant Information No Cleaning Needed Recommended Maintenance Additional Notes: Damage to Plants Plant Replacement Plant Trimming Schedule Maintenance as Planned Needs Immediate Maintenance 5796 Armada Drive #250, Carlsbad, CA | 855.566.3938 | stormwater@forterrabp.com | www.biocleanenvironmental.com For Office Use Only (city) (Zip Code)(Reviewed By) Owner / Management Company (Date) Contact Phone ( )_ Inspector Name Date / /Time AM / PM Weather Condition Additional Notes Site Map # Comments: Inlet and Outlet Pipe Condition Drain Down Pipe Condition Discharge Chamber Condition Drain Down Media Condition Plant Condition Media Filter Condition Long: MWS Sedimentation Basin Total Debris Accumulation Condition of Media 25/50/75/100 (will be changed @ 75%) Operational Per Manufactures' Specifications (If not, why?) Lat:MWS Catch Basins GPS Coordinates of Insert Manufacturer / Description / Sizing Trash Accumulation Foliage Accumulation Sediment Accumulation Type of Inspection Routine Follow Up Complaint Storm Storm Event in Last 72-hours? No Yes Office personnel to complete section to the left. Project Address Project Name Cleaning and Maintenance Report Modular Wetlands Linear 5796 Armada Drive #250, Carlsbad, CA | 855.566.3938 | stormwater@forterrabp.com | www.biocleanenvironmental.com APPENDIX A MAINTENANCE REQUIREMENTS FOR STORMWATER FACILITIES AND ON-SITE BMPS 12/12/2016 2017 City of Renton Surface Water Design Manual A-6 NO. 3 – DETENTION TANKS AND VAULTS MAINTENANCE COMPONENT DEFECT OR PROBLEM CONDITIONS WHEN MAINTENANCE IS NEEDED RESULTS EXPECTED WHEN MAINTENANCE IS PERFORMED Site Trash and debris Any trash and debris which exceed 1 cubic foot per 1,000 square feet (this is about equal to the amount of trash it would take to fill up one standard size office garbage can). In general, there should be no visual evidence of dumping. Trash and debris cleared from site. Noxious weeds Any noxious or nuisance vegetation which may constitute a hazard to City personnel or the public. Noxious and nuisance vegetation removed according to applicable regulations. No danger of noxious vegetation where City personnel or the public might normally be. Contaminants and pollution Any evidence of contaminants or pollution such as oil, gasoline, concrete slurries or paint. Materials removed and disposed of according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Excessive growth of grass/groundcover Grass or groundcover exceeds 18 inches in height. Grass or groundcover mowed to a height no greater than 6 inches. Tank or Vault Storage Area Trash and debris Any trash and debris accumulated in vault or tank (includes floatables and non- floatables). No trash or debris in vault. Sediment accumulation Accumulated sediment depth exceeds 10% of the diameter of the storage area for ½ length of storage vault or any point depth exceeds 15% of diameter. Example: 72-inch storage tank would require cleaning when sediment reaches depth of 7 inches for more than ½ length of tank. All sediment removed from storage area. Tank Structure Plugged air vent Any blockage of the vent. Tank or vault freely vents. Tank bent out of shape Any part of tank/pipe is bent out of shape more than 10% of its design shape. Tank repaired or replaced to design. Gaps between sections, damaged joints or cracks or tears in wall A gap wider than ½-inch at the joint of any tank sections or any evidence of soil particles entering the tank at a joint or through a wall. No water or soil entering tank through joints or walls. Vault Structure Damage to wall, frame, bottom, and/or top slab Cracks wider than ½-inch, any evidence of soil entering the structure through cracks or qualified inspection personnel determines that the vault is not structurally sound. Vault is sealed and structurally sound. Inlet/Outlet Pipes Sediment accumulation Sediment filling 20% or more of the pipe. Inlet/outlet pipes clear of sediment. Trash and debris Trash and debris accumulated in inlet/outlet pipes (includes floatables and non-floatables). No trash or debris in pipes. Damaged inlet/outlet pipes Cracks wider than ½-inch at the joint of the inlet/outlet pipes or any evidence of soil entering at the joints of the inlet/outlet pipes. No cracks more than ¼-inch wide at the joint of the inlet/outlet pipe. Access Manhole Cover/lid not in place Cover/lid is missing or only partially in place. Any open manhole requires immediate maintenance. Manhole access covered. APPENDIX A MAINTENANCE REQUIREMENTS FOR STORMWATER FACILITIES AND ON-SITE BMPS 2017 City of Renton Surface Water Design Manual 12/12/2016 A-7 NO. 3 – DETENTION TANKS AND VAULTS MAINTENANCE COMPONENT DEFECT OR PROBLEM CONDITIONS WHEN MAINTENANCE IS NEEDED RESULTS EXPECTED WHEN MAINTENANCE IS PERFORMED Access Manhole (cont.) Locking mechanism not working Mechanism cannot be opened by one maintenance person with proper tools. Bolts cannot be seated. Self-locking cover/lid does not work. Mechanism opens with proper tools. Cover/lid difficult to remove One maintenance person cannot remove cover/lid after applying 80 lbs of lift. Cover/lid can be removed and reinstalled by one maintenance person. Ladder rungs unsafe Missing rungs, misalignment, rust, or cracks. Ladder meets design standards. Allows maintenance person safe access. Large access doors/plate Damaged or difficult to open Large access doors or plates cannot be opened/removed using normal equipment. Replace or repair access door so it can opened as designed. Gaps, doesn't cover completely Large access doors not flat and/or access opening not completely covered. Doors close flat; covers access opening completely. Lifting rings missing, rusted Lifting rings not capable of lifting weight of door or plate. Lifting rings sufficient to lift or remove door or plate. APPENDIX A MAINTENANCE REQUIREMENTS FOR STORMWATER FACILITIES AND ON-SITE BMPS 12/12/2016 2017 City of Renton Surface Water Design Manual A-8 NO. 4 – CONTROL STRUCTURE/FLOW RESTRICTOR MAINTENANCE COMPONENT DEFECT OR PROBLEM CONDITION WHEN MAINTENANCE IS NEEDED RESULTS EXPECTED WHEN MAINTENANCE IS PERFORMED Structure Trash and debris Trash or debris of more than ½ cubic foot which is located immediately in front of the structure opening or is blocking capacity of the structure by more than 10%. No Trash or debris blocking or potentially blocking entrance to structure. Trash or debris in the structure that exceeds 1/3 the depth from the bottom of basin to invert the lowest pipe into or out of the basin. No trash or debris in the structure. Deposits of garbage exceeding 1 cubic foot in volume. No condition present which would attract or support the breeding of insects or rodents. Sediment accumulation Sediment exceeds 60% of the depth from the bottom of the structure to the invert of the lowest pipe into or out of the structure or the bottom of the FROP-T section or is within 6 inches of the invert of the lowest pipe into or out of the structure or the bottom of the FROP-T section. Sump of structure contains no sediment. Damage to frame and/or top slab Corner of frame extends more than ¾ inch past curb face into the street (If applicable). Frame is even with curb. Top slab has holes larger than 2 square inches or cracks wider than ¼ inch. Top slab is free of holes and cracks. Frame not sitting flush on top slab, i.e., separation of more than ¾ inch of the frame from the top slab. Frame is sitting flush on top slab. Cracks in walls or bottom Cracks wider than ½ inch and longer than 3 feet, any evidence of soil particles entering structure through cracks, or maintenance person judges that structure is unsound. Structure is sealed and structurally sound. Cracks wider than ½ inch and longer than 1 foot at the joint of any inlet/outlet pipe or any evidence of soil particles entering structure through cracks. No cracks more than 1/4 inch wide at the joint of inlet/outlet pipe. Settlement/ misalignment Structure has settled more than 1 inch or has rotated more than 2 inches out of alignment. Basin replaced or repaired to design standards. Damaged pipe joints Cracks wider than ½-inch at the joint of the inlet/outlet pipes or any evidence of soil entering the structure at the joint of the inlet/outlet pipes. No cracks more than ¼-inch wide at the joint of inlet/outlet pipes. Contaminants and pollution Any evidence of contaminants or pollution such as oil, gasoline, concrete slurries or paint. Materials removed and disposed of according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Ladder rungs missing or unsafe Ladder is unsafe due to missing rungs, misalignment, rust, cracks, or sharp edges. Ladder meets design standards and allows maintenance person safe access. FROP-T Section Damaged FROP-T T section is not securely attached to structure wall and outlet pipe structure should support at least 1,000 lbs of up or down pressure. T section securely attached to wall and outlet pipe. Structure is not in upright position (allow up to 10% from plumb). Structure in correct position. APPENDIX A MAINTENANCE REQUIREMENTS FOR STORMWATER FACILITIES AND ON-SITE BMPS 2017 City of Renton Surface Water Design Manual 12/12/2016 A-9 NO. 4 – CONTROL STRUCTURE/FLOW RESTRICTOR MAINTENANCE COMPONENT DEFECT OR PROBLEM CONDITION WHEN MAINTENANCE IS NEEDED RESULTS EXPECTED WHEN MAINTENANCE IS PERFORMED FROP-T Section (cont.) Damaged FROP-T (cont.) Connections to outlet pipe are not watertight or show signs of deteriorated grout. Connections to outlet pipe are water tight; structure repaired or replaced and works as designed. Any holes—other than designed holes—in the structure. Structure has no holes other than designed holes. Cleanout Gate Damaged or missing cleanout gate Cleanout gate is missing. Replace cleanout gate. Cleanout gate is not watertight. Gate is watertight and works as designed. Gate cannot be moved up and down by one maintenance person. Gate moves up and down easily and is watertight. Chain/rod leading to gate is missing or damaged. Chain is in place and works as designed. Orifice Plate Damaged or missing orifice plate Control device is not working properly due to missing, out of place, or bent orifice plate. Plate is in place and works as designed. Obstructions to orifice plate Any trash, debris, sediment, or vegetation blocking the plate. Plate is free of all obstructions and works as designed. Overflow Pipe Obstructions to overflow pipe Any trash or debris blocking (or having the potential of blocking) the overflow pipe. Pipe is free of all obstructions and works as designed. Deformed or damaged lip of overflow pipe Lip of overflow pipe is bent or deformed. Overflow pipe does not allow overflow at an elevation lower than design Inlet/Outlet Pipe Sediment accumulation Sediment filling 20% or more of the pipe. Inlet/outlet pipes clear of sediment. Trash and debris Trash and debris accumulated in inlet/outlet pipes (includes floatables and non-floatables). No trash or debris in pipes. Damaged inlet/outlet pipe Cracks wider than ½-inch at the joint of the inlet/outlet pipes or any evidence of soil entering at the joints of the inlet/outlet pipes. No cracks more than ¼-inch wide at the joint of the inlet/outlet pipe. Metal Grates (If applicable) Unsafe grate opening Grate with opening wider than 7/8 inch. Grate opening meets design standards. Trash and debris Trash and debris that is blocking more than 20% of grate surface. Grate free of trash and debris. footnote to guidelines for disposal Damaged or missing grate Grate missing or broken member(s) of the grate. Grate is in place and meets design standards. Manhole Cover/Lid Cover/lid not in place Cover/lid is missing or only partially in place. Any open structure requires urgent maintenance. Cover/lid protects opening to structure. Locking mechanism not working Mechanism cannot be opened by one maintenance person with proper tools. Bolts cannot be seated. Self-locking cover/lid does not work. Mechanism opens with proper tools. Cover/lid difficult to remove One maintenance person cannot remove cover/lid after applying 80 lbs. of lift. Cover/lid can be removed and reinstalled by one maintenance person. APPENDIX A MAINTENANCE REQUIREMENTS FOR FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES NO. 5 – CATCH BASINS AND MANHOLES Maintenance Component Defect or Problem Condition When Maintenance is Needed Results Expected When Maintenance is Performed Structure Sediment Sediment exceeds 60% of the depth from the bottom of the catch basin to the invert of the lowest pipe into or out of the catch basin or is within 6 inches of the invert of the lowest pipe into or out of the catch basin. Sump of catch basin contains no sediment. Trash and debris Trash or debris of more than ½ cubic foot which is located immediately in front of the catch basin opening or is blocking capacity of the catch basin by more than 10%. No Trash or debris blocking or potentially blocking entrance to catch basin. Trash or debris in the catch basin that exceeds 1/3 the depth from the bottom of basin to invert the lowest pipe into or out of the basin. No trash or debris in the catch basin. Dead animals or vegetation that could generate odors that could cause complaints or dangerous gases (e.g., methane). No dead animals or vegetation present within catch basin. Deposits of garbage exceeding 1 cubic foot in volume. No condition present which would attract or support the breeding of insects or rodents. Damage to frame and/or top slab Corner of frame extends more than ¾ inch past curb face into the street (If applicable). Frame is even with curb. Top slab has holes larger than 2 square inches or cracks wider than ¼ inch. Top slab is free of holes and cracks. Frame not sitting flush on top slab, i.e., separation of more than ¾ inch of the frame from the top slab. Frame is sitting flush on top slab. Cracks in walls or bottom Cracks wider than ½ inch and longer than 3 feet, any evidence of soil particles entering catch basin through cracks, or maintenance person judges that catch basin is unsound. Catch basin is sealed and is structurally sound. Cracks wider than ½ inch and longer than 1 foot at the joint of any inlet/outlet pipe or any evidence of soil particles entering catch basin through cracks. No cracks more than 1/4 inch wide at the joint of inlet/outlet pipe. Settlement/ misalignment Catch basin has settled more than 1 inch or has rotated more than 2 inches out of alignment. Basin replaced or repaired to design standards. Damaged pipe joints Cracks wider than ½-inch at the joint of the inlet/outlet pipes or any evidence of soil entering the catch basin at the joint of the inlet/outlet pipes. No cracks more than ¼-inch wide at the joint of inlet/outlet pipes. Contaminants and pollution Any evidence of contaminants or pollution such as oil, gasoline, concrete slurries or paint. Materials removed and disposed of according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Inlet/Outlet Pipe Sediment accumulation Sediment filling 20% or more of the pipe. Inlet/outlet pipes clear of sediment. Trash and debris Trash and debris accumulated in inlet/outlet pipes (includes floatables and non-floatables). No trash or debris in pipes. Damaged Cracks wider than ½-inch at the joint of the inlet/outlet pipes or any evidence of soil entering at the joints of the inlet/outlet pipes. No cracks more than ¼-inch wide at the joint of the inlet/outlet pipe. 2016 Surface Water Design Manual – Appendix A 4/24/2016A-9 APPENDIX A MAINTENANCE REQUIREMENTS FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES NO. 5 – CATCH BASINS AND MANHOLES Maintenance Component Defect or Problem Condition When Maintenance is Needed Results Expected When Maintenance is Performed Metal Grates (Catch Basins) Unsafe grate opening Grate with opening wider than 7/8 inch. Grate opening meets design standards. Trash and debris Trash and debris that is blocking more than 20% of grate surface. Grate free of trash and debris. footnote to guidelines for disposal Damaged or missing Grate missing or broken member(s) of the grate. Any open structure requires urgent maintenance. Grate is in place and meets design standards. Manhole Cover/Lid Cover/lid not in place Cover/lid is missing or only partially in place. Any open structure requires urgent maintenance. Cover/lid protects opening to structure. Locking mechanism Not Working Mechanism cannot be opened by one maintenance person with proper tools. Bolts cannot be seated. Self-locking cover/lid does not work. Mechanism opens with proper tools. Cover/lid difficult to Remove One maintenance person cannot remove cover/lid after applying 80 lbs. of lift. Cover/lid can be removed and reinstalled by one maintenance person. 4/24/2016 2016 Surface Water Design Manual – Appendix AA-10 APPENDIX A MAINTENANCE REQUIREMENTS FOR FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES NO. 6 – CONVEYANCE PIPES AND DITCHES Maintenance Component Defect or Problem Conditions When Maintenance is Needed Results Expected When Maintenance is Performed Pipes Sediment & debris accumulation Accumulated sediment or debris that exceeds 20% of the diameter of the pipe. Water flows freely through pipes. Vegetation/roots Vegetation/roots that reduce free movement of water through pipes. Water flows freely through pipes. Contaminants and pollution Any evidence of contaminants or pollution such as oil, gasoline, concrete slurries or paint. Materials removed and disposed of according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Damage to protective coating or corrosion Protective coating is damaged; rust or corrosion is weakening the structural integrity of any part of pipe. Pipe repaired or replaced. Damaged Any dent that decreases the cross section area of pipe by more than 20% or is determined to have weakened structural integrity of the pipe. Pipe repaired or replaced. Ditches Trash and debris Trash and debris exceeds 1 cubic foot per 1,000 square feet of ditch and slopes. Trash and debris cleared from ditches. Sediment accumulation Accumulated sediment that exceeds 20% of the design depth. Ditch cleaned/flushed of all sediment and debris so that it matches design. Noxious weeds Any noxious or nuisance vegetation which may constitute a hazard to County personnel or the public. Noxious and nuisance vegetation removed according to applicable regulations. No danger of noxious vegetation where County personnel or the public might normally be. Contaminants and pollution Any evidence of contaminants or pollution such as oil, gasoline, concrete slurries or paint. Materials removed and disposed of according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Vegetation Vegetation that reduces free movement of water through ditches. Water flows freely through ditches. Erosion damage to slopes Any erosion observed on a ditch slope. Slopes are not eroding. Rock lining out of place or missing (If Applicable) One layer or less of rock exists above native soil area 5 square feet or more, any exposed native soil. Replace rocks to design standards. 2016 Surface Water Design Manual – Appendix A 4/24/2016A-11 APPENDIX A MAINTENANCE REQUIREMENTS FOR STORMWATER FACILITIES AND ON-SITE BMPS 2017 City of Renton Surface Water Design Manual 12/12/2016 A-17 NO. 11 – GROUNDS (LANDSCAPING) MAINTENANCE COMPONENT DEFECT OR PROBLEM CONDITIONS WHEN MAINTENANCE IS NEEDED RESULTS EXPECTED WHEN MAINTENANCE IS PERFORMED Site Trash and debris Any trash and debris which exceed 1 cubic foot per 1,000 square feet (this is about equal to the amount of trash it would take to fill up one standard size office garbage can). In general, there should be no visual evidence of dumping. Trash and debris cleared from site. Noxious weeds Any noxious or nuisance vegetation which may constitute a hazard to City personnel or the public. Noxious and nuisance vegetation removed according to applicable regulations. No danger of noxious vegetation where City personnel or the public might normally be. Contaminants and pollution Any evidence of contaminants or pollution such as oil, gasoline, concrete slurries or paint. Materials removed and disposed of according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Excessive growth of grass/groundcover Grass or groundcover exceeds 18 inches in height. Grass or groundcover mowed to a height no greater than 6 inches. Trees and Shrubs Hazard tree identified Any tree or limb of a tree identified as having a potential to fall and cause property damage or threaten human life. A hazard tree identified by a qualified arborist must be removed as soon as possible. No hazard trees in facility. Damaged tree or shrub identified Limbs or parts of trees or shrubs that are split or broken which affect more than 25% of the total foliage of the tree or shrub. Trees and shrubs with less than 5% of total foliage with split or broken limbs. Trees or shrubs that have been blown down or knocked over. No blown down vegetation or knocked over vegetation. Trees or shrubs free of injury. Trees or shrubs which are not adequately supported or are leaning over, causing exposure of the roots. Tree or shrub in place and adequately supported; dead or diseased trees removed. APPENDIX A MAINTENANCE REQUIREMENTS FOR STORMWATER FACILITIES AND ON-SITE BMPS 2017 City of Renton Surface Water Design Manual 12/12/2016 A-41 NO. 30 – PERMEABLE PAVEMENT BMP MAINTENANCE COMPONENT DEFECT OR PROBLEM CONDITIONS WHEN MAINTENANCE IS NEEDED RESULTS EXPECTED WHEN MAINTENANCE IS PERFORMED Preventive Surface cleaning/ vegetation control Media surface vacuumed or pressure washed annually, vegetation controlled to design maximum. Weed growth suggesting sediment accumulation. No dirt, sediment, or debris clogging porous media, or vegetation limiting infiltration. Porous Concrete, Porous Asphaltic Concrete, and Permeable Pavers Trash and debris Trash and debris on the pavement interfering with infiltration; leaf drop in fall season. No trash or debris interfering with infiltration. Sediment accumulation Sediment accumulation on the pavement interfering with infiltration; runoff from adjacent areas depositing sediment/debris on pavement. Pavement infiltrates as designed; adjacent areas stabilized. Insufficient infiltration rate Pavement does not infiltrate at a rate of 10 inches per hour. Pavement infiltrates at a rate greater than 10 inches per hour. Excessive ponding Standing water for a long period of time on the surface of the pavement. Standing water infiltrates at the desired rate. Broken or cracked pavement Pavement is broken or cracked. No broken pavement or cracks on the surface of the pavement. Settlement Uneven pavement surface indicating settlement of the subsurface layer. Pavement surface is uniformly level. Moss growth Moss growing on pavement interfering with infiltration. No moss interferes with infiltration. Inflow restricted Inflow to the pavement is diverted, restricted, or depositing sediment and debris on the pavement. Inflow to pavement is unobstructed and not bringing sediment or debris to the pavement. Underdrain not freely flowing Underdrain is not flowing when pavement has been infiltrating water. Underdrain flows freely when water is present. Overflow not controlling excess water Overflow not controlling excess water to desired location; native soil is exposed or other signs of erosion damage are present. Overflow permits excess water to leave the site at the desired location; Overflow is stabilized and appropriately armored. Permeable Pavers Broken or missing pavers Broken or missing paving blocks on surface of pavement. No missing or broken paving blocks interfering with infiltration. Uneven surface Uneven surface due to settlement or scour of fill in the interstices of the paving blocks. Pavement surface is uniformly level. Compaction Poor infiltration due to soil compaction between paving blocks. No soil compaction in the interstices of the paver blocks limiting infiltration. Poor vegetation growth (if applicable) Grass in the interstices of the paving blocks is dead. Healthy grass is growing in the interstices of the paver blocks. APPENDIX E Bond Quantities (submitted separately), Facility Summaries, and Declaration of Drainage Covenant Page 1 of ___ Return Address: City Clerk’s Office City of Renton 1055 S Grady Way Renton, WA 98057 DECLARATION OF COVENANT FOR INSPECTION AND MAINTENANCE OF DRAINAGE FACILITIES AND ON-SITE BMPS Grantor: Grantee: City of Renton, a Washington municipal corporation Legal Description: Assessor's Tax Parcel ID#: IN CONSIDERATION of the approved City of Renton (check one of the following) Residential Building Permit Commercial Building Permit Clearing and Grading Permit Civil Construction or Utility Permit for Permit(s)_____________________ (Construction/Building/Utility Permit #) relating to the real property ("Property") described above, the Grantor(s), the owner(s) in fee of that Property, hereby covenants (covenant) with the City of Renton (“City of Renton” or “City”), a municipal corporation of the state of Washington, that he/she (they) will observe, consent to, and abide by the conditions and obligations set forth and described in Paragraphs 1 through 9 below with regard to the Property, and hereby grants (grant) an easement as described in Paragraphs 2 and 3. Grantor(s) hereby grants (grant), covenants (covenant), and agrees (agree) as follows: 1.The Grantor(s) or his/her (their) successors in interest and assigns ("Owners ") shall at their own cost, operate, maintain, and keep in good repair, the Property's drainage facilities constructed as required in the approved construction plans and specifications __________________ (Project Plan #) on file with the City of Renton and submitted to the City of Renton for the review and approval of permit(s) _____________________________ (Construction/Building/Utility Permit #). The Property's drainage facilities are shown and/or listed on Exhibit A – Site Plan. The Property’s drainage facilities shall be maintained in compliance with the operation and maintenance schedule included and attached herein as Exhibit B – Operations and Maintenance. Drainage facilities include pipes, channels, flow control facilities, water quality facilities, on-site best management practices (BMPs) and other engineered structures designed to manage and/or 9332 Page 2 of ___ treat stormwater on the Property. On-site BMPs include dispersion and infiltration devices, bioretention, permeable pavements, rainwater harvesting systems, tree retention credit, reduced impervious surface footprint, vegetated roofs and other measures designed to mimic pre-developed hydrology and minimize stormwater runoff on the Property. 2.City of Renton shall have the right to ingress and egress over those portions of the Property necessary to perform inspections of the stormwater facilities and BMPs and conduct maintenance activities specified in this Declaration of Covenant and in accordance with the Renton Municipal Code. City of Renton shall provide at least thirty (30) days’ written notice to the Owners that entry on the Property is planned for the inspection of drainage facilities. After the thirty (30) days, the Owners shall allow the City of Renton to enter for the sole purpose of inspecting drainage facilities. In lieu of inspection by the City, the Owners may elect to engage a licensed civil engineer registered in the state of Washington who has expertise in drainage to inspect the drainage facilities and provide a written report describing their condition. If the engineer option is chosen, the Owners shall provide written notice to the City of Renton within fifteen (15) days of receiving the City’s notice of inspection. Within thirty (30) days of giving this notice, the Owners, or engineer on behalf of the Owners, shall provide the engineer’s report to the City of Renton. If the report is not provided in a timely manner as specified above, the City of Renton may inspect the drainage facilities without further notice. 3.If City of Renton determines from its inspection, or from an engineer’s report provided in accordance with Paragraph 2, that maintenance, repair, restoration, and/or mitigation work is required to be done to any of the drainage facilities, City of Renton shall notify the Owners of the specific maintenance, repair, restoration, and/or mitigation work (“Work”) required pursuant to the Renton Municipal Code. The City shall also set a reasonable deadline for the Owners to complete the Work, or to provide an engineer’s report that verifies completion of the Work. After the deadline has passed, the Owners shall allow the City access to re-inspect the drainage facilities unless an engineer’s report has been provided verifying completion of the Work. If the Work is not completed within the time frame set by the City, the City may initiate an enforcement action and/or perform the Work and hereby is given access to the Property for such purposes. Written notice will be sent to the Owners stating the City’s intention to perform such Work. This Work will not commence until at least seven (7) days after such notice is mailed. If, within the sole discretion of the City, there exists an imminent or present danger, the seven (7) day notice period will be waived and Work will begin immediately. 4.The Owners shall assume all responsibility for the cost of any Work, or any measures taken by the City to address conditions as described in Paragraph 3. Such responsibility shall include reimbursement to the City within thirty (30) days of the receipt of the invoice for any such Work performed. Overdue payments will require payment of interest at the maximum legal rate allowed by RCW 19.52.020 (currently twelve percent (12%)). If the City initiates legal action to enforce this agreement, the prevailing party in such action is entitled to recover reasonable litigation costs and attorney’s fees. 5.The Owners are required to obtain written approval from City of Renton prior to filling, piping, cutting, or removing vegetation (except in routine landscape maintenance) in open vegetated stormwater facilities (such as swales, channels, ditches, ponds, etc.), or performing any alterations or modifications to the drainage facilities referenced in this Declaration of Covenant. Page 3 of ___ 6.Any notice or consent required to be given or otherwise provided for by the provisions of this Agreement shall be effective upon personal delivery, or three (3) days after mailing by Certified Mail, return receipt requested. 7.With regard to the matters addressed herein, this agreement constitutes the entire agreement between the parties, and supersedes all prior discussions, negotiations, and all agreements whatsoever whether oral or written. 8.This Declaration of Covenant is intended to protect the value and desirability and promote efficient and effective management of surface water drainage of the real property described above, and shall inure to the benefit of all the citizens of the City of Renton and its successors and assigns. This Declaration of Covenant shall run with the land and be binding upon Grantor(s), and Grantor's(s') successors in interest, and assigns. 9.This Declaration of Covenant may be terminated by execution of a written agreement by the Owners and the City that is recorded by King County in its real property records. IN WITNESS WHEREOF, this Declaration of Covenant for the Inspection and Maintenance of Drainage Facilities is executed this _____ day of ____________________, 20_____. GRANTOR, owner of the Property GRANTOR, owner of the Property STATE OF WASHINGTON ) COUNTY OF KING )ss. On this day personally appeared before me: , to me known to be the individual(s) described in and who executed the within and foregoing instrument and acknowledged that they signed the same as their free and voluntary act and deed, for the uses and purposes therein stated. Given under my hand and official seal this _____ day of ___________________, 20_____. Printed name Notary Public in and for the State of Washington, residing at My appointment expires 1932 1st Ave,Suite 201,Seattle, WA 98101p. 206.725.1211f. 206.973.5344www.lpdengineering.comengineering pllc2021 LPD Engineering PLLC©NEW ELEMENTARY SCHOOL #164PROPOSED CONDITIONSEXHIBIT A EXHIBIT B EXHIBIT B EXHIBIT B Page 6 of ___ Exhibit C – Legal Description Please replace this page with “Exhibit C – Legal Description” if the property legal description does not fit within the space provided on Page 1 of the Declaration of Covenant. Add reference to “Exhibit C” in the legal description field on page 1 of the Declaration of Covenant document. REFER TO SHEET C2.8 IN APPENDIX A OF THE TIR FOR WATER QUALITY FACILITY DETAIL REFER TO SHEET C2.8-2.11 IN APPENDIX A OF THE TIR FOR DETENTION FACILITY DETAILS REFER TO SHEET C2.8 IN APPENDIX A OF THE TIR FOR WATER QUALITY FACILITY DETAIL REFER TO SHEET C2.8-2.11 IN APPENDIX A OF THE TIR FOR DETENTION FACILITY DETAILS REFER TO SHEET C2.7 IN APPENDIX A OF THE TIR FOR FULL DIPERSION GRAVEL FILL TRENCH DETAIL APPENDIX F Special Reports and Studies associated earth sciences incorporated Associated Earth Sciences, Inc. 911 5th Avenue Kirkland, WA 98033 P (425) 827 7701 Subsurface Exploration and Preliminary Geotechnical Engineering Report RENTON SCHOOL DISTRICT ELEMENTARY SCHOOL NO. 16 Renton, Washington Prepared For: RENTON SCHOOL DISTRICT November 23, 2020 Project No. 20180398E002 Kirkland | Tacoma | Mount Vernon 425-827-7701 | www.aesgeo.com November 23, 2020 Project No. 20180398E002 Renton School District 7812 South 124th Street Seattle, Washington 98178 Attention: Ms. Traci Brewer-Rogstad Subject: Subsurface Exploration and Preliminary Geotechnical Engineering Report Renton School District Elementary School No. 16 Renton, Washington Dear Ms. Brewer-Rogstad: We are pleased to present this preliminary geotechnical engineering report for the referenced project. This report summarizes the results of our subsurface exploration and presents preliminary recommendations for design and construction of a new school at the site. Detailed project plans have not been prepared, and therefore our recommendations are preliminary. We recommend that we be allowed to review final project plans when they are developed and update our recommendations as needed. An earlier draft of this report was prepared, dated November 21, 2019. This updated report incorporates data from six additional recently completed exploration borings and incorporates a site development concept that was not previously available. We have enjoyed working with you on this study and are confident that the recommendations presented in this report will aid in the successful completion of your project. If you should have any questions or if we can be of additional help to you, please do not hesitate to call. Sincerely, ASSOCIATED EARTH SCIENCES, INC. Kirkland, Washington ______________________________ Kurt D. Merriman, P.E. Senior Principal Engineer KDM/ld - 20180398E002-3 SUBSURFACE EXPLORATION AND PRELIMINARY GEOTECHNICAL ENGINEERING REPORT RENTON SCHOOL DISTRICT ELEMENTARY SCHOOL NO. 16 Renton, Washington Prepared for: Renton School District 7812 South 124th Street Seattle, Washington 98178 Prepared by: Associated Earth Sciences, Inc. 911 5th Avenue Kirkland, Washington 98033 425-827-7701 November 23, 2020 Project No. 20180398E002 Subsurface Exploration and Renton School District Elementary School No. 16 Preliminary Geotechnical Engineering Report Renton, Washington Project and Site Conditions November 23, 2020 ASSOSCIATED EARTH SCIENCES, INC. CRC/ld - 20180398E002-3 Page 1 I. PROJECT AND SITE CONDITIONS 1.0 INTRODUCTION This report summarizes the results of our subsurface exploration and preliminary geotechnical engineering study for the Renton Elementary School No. 16 project. Our recommendations are preliminary in that the project is still in conceptual planning. Recommendations in this report are based on a “Site Coordination Plan” by Hutteball + Oremus Architecture dated October 21, 2020 and an ALTA survey titled “Renton School District Chelan Ave. NE Project” by Terrane dated October 12, 2020. The site location is shown on the “Vicinity Map,” Figure 1. The approximate locations of explorations completed for this study are shown on the “Site and Exploration Plan,” Figure 2. A Light Detection and Ranging (LIDAR)-based “Existing Site and Exploration Plan” is included as Figure 3. Interpretive exploration logs and laboratory test results are included in the Appendix. 1.1 Purpose and Scope The purpose of our preliminary study is to provide subsurface exploration data and preliminary geotechnical engineering recommendations for use during project design. Our study included a review of selected available geologic literature, advancing 20 exploration borings, and performing geologic studies to assess the type, thickness, distribution, and physical properties of the subsurface sediments and shallow groundwater. Geotechnical engineering studies were completed to formulate preliminary recommendations for geotechnical critical areas, site preparation, grading, types of suitable foundations and floors, allowable foundation soil bearing pressure, anticipated foundation and floor settlement, drainage considerations, and infiltration feasibility. This report summarizes our fieldwork and offers preliminary recommendations based on our present understanding of the project. We recommend that we be allowed to review the recommendations presented in this report and revise them, if needed, when the project has been designed. 1.2 Authorization Our study was authorized by means of a District purchase order. This report has been prepared for the exclusive use of the Renton School District (RSD) for specific application to this project. Within the limitations of scope, schedule, and budget, our services have been performed in accordance with generally accepted geotechnical engineering and engineering geology practices in effect in this area at the time our report was prepared. No other warranty, express or implied, is made. Subsurface Exploration and Renton School District Elementary School No. 16 Preliminary Geotechnical Engineering Report Renton, Washington Project and Site Conditions November 23, 2020 ASSOSCIATED EARTH SCIENCES, INC. CRC/ld - 20180398E002-3 Page 2 2.0 PROJECT AND SITE DESCRIPTION The subject site includes 11 residential parcels totaling approximately 12.78 acres in total area. Until recently the project site was developed with homes and mature landscaping. The houses were recently demolished and the majority of the landscaping removed. The site includes slope areas highlighted by the City of Renton as potentially meeting criteria for treatment as geotechnical critical areas. Geotechnical critical areas are discussed in detail later in this report. We understand that a wetland has been delineated on the west side and in a low area along Duvall Avenue NE in the northeast corner of the site. The current project concept calls for construction of a new elementary school building near the center of the project site. A paved parking area is planned south of the school building, with hard and soft surface play areas to the north. Wetland areas to the west will be left undisturbed. Construction close to existing grade is expected, without deep excavation or thick structural fill. 3.0 SUBSURFACE EXPLORATION Our field study included advancing a total of 20 exploration borings across the site. Exploration borings EB-1 through EB-8 were advanced on August 22, 2018, EB-9 through EB-14 were advanced on September 27, 2019, and EB-15 through EB-20 were advanced on October 6, 2020. The conclusions and recommendations presented in this report are based on the explorations completed for this study. The number, locations, and depths of our explorations were completed within site and budgetary constraints. Our explorations were approximately located in the field relative to known site features shown on Figures 2 and 3. Interpretive exploration logs and laboratory test results are presented in the Appendix. Because of the nature of exploratory work below ground, extrapolation of subsurface conditions between field explorations is necessary. It should be noted that differing subsurface conditions may sometimes be present due to the random nature of deposition and the alteration of topography by past grading and/or filling. The nature and extent of any variations between the field explorations may not become fully evident until construction. If variations are observed at that time, it may be necessary to re-evaluate specific recommendations in this report and make appropriate changes. 3.1 Exploration Borings The exploration borings were completed by advancing hollow-stem auger tools with a limited-access track-mounted drill rig. During the drilling process, samples were obtained at generally 2.5- to 5-foot-depth intervals. The exploration borings were continuously observed Subsurface Exploration and Renton School District Elementary School No. 16 Preliminary Geotechnical Engineering Report Renton, Washington Project and Site Conditions November 23, 2020 ASSOSCIATED EARTH SCIENCES, INC. CRC/ld - 20180398E002-3 Page 3 and logged by a representative from our firm. The exploration logs presented in the Appendix are based on the field logs, drilling action, and inspection of the samples secured. Disturbed, but representative samples were obtained by using the Standard Penetration Test (SPT) procedure in accordance with ASTM International (ASTM) D-1586. This test and sampling method consists of driving a standard 2-inch, outside-diameter, split-barrel sampler a distance of 18 inches into the soil with a 140-pound hammer free-falling a distance of 30 inches. The number of blows for each 6-inch interval is recorded, and the number of blows required to drive the sampler the final 12 inches is known as the Standard Penetration Resistance (“N”) or blow count. If a total of 50 is recorded within one 6-inch interval, the blow count is recorded as the number of blows for the corresponding number of inches of penetration. The resistance, or N-value, provides a measure of the relative density of granular soils or the relative consistency of cohesive soils; these values are plotted on the attached exploration boring logs. The samples obtained from the split-barrel sampler were classified in the field and representative portions placed in watertight containers. The samples were then transported to our laboratory for further visual classification and laboratory testing. 4.0 SUBSURFACE CONDITIONS Subsurface conditions at the project site were inferred from the field explorations accomplished for this study, visual reconnaissance of the site, and review of selected geologic literature. The general distribution of geologic units is shown on the exploration logs. The explorations typically encountered native materials consisting of medium dense grading to very dense lodgement till sediments. Ten exploration borings encountered surficial existing fill to depths of up to approximately 7 feet below the existing ground surface. Two explorations (EB-10 and EB-11) encountered thin layers of fine sand interpreted as Vashon recessional outwash. The northernmost exploration borings (EB-13 and EB-14) terminated at depths of approximately 20.5 to 21.5 feet in stratified sediments that appear to represent lodgement till to advance outwash transition sediments. 4.1 Stratigraphy Grass/Topsoil/Forest Duff A surficial layer of grass and organic topsoil was encountered at the location of each of the exploration locations. This organic layer was approximately 6 inches thick or less at most boring locations, and thicker at three locations. Observed topsoil thickness is shown on the attached subsurface exploration logs. Subsurface Exploration and Renton School District Elementary School No. 16 Preliminary Geotechnical Engineering Report Renton, Washington Project and Site Conditions November 23, 2020 ASSOSCIATED EARTH SCIENCES, INC. CRC/ld - 20180398E002-3 Page 4 Due to their high organic content, these materials are not considered suitable for foundation, roadway, or slab-on-grade floor support, or for use in a structural fill. Fill Existing fill was observed in exploration borings EB-3, EB-4, EB-10, EB-12, EB-13, EB-14, EB-15, EB-18, EB-19, and EB-20 to depths of approximately 1.5 to 7 feet below existing ground level. The observed existing fill consists of loose to medium dense silty to very silty sand with varying amounts of gravel and includes some charcoal and other organic material. We anticipate that additional existing fill will be encountered at the locations of former structures and buried utilities. Excavated existing fill material is suitable for reuse in structural fill applications if such reuse is specifically allowed by project plans and specifications, if excessively organic and any other deleterious materials are removed, and moisture content is adjusted to allow compaction to the specified level and to a firm and unyielding condition. Based on our explorations completed for this study, we estimate the observed existing fill was above optimum moisture content for compaction purposes, and therefore may require drying during favorable weather prior to compaction in structural fill applications. Vashon Recessional Outwash Exploration borings EB-10 and EB-11 encountered loose to medium dense sand, with variable amounts of gravel and varying silt content interpreted as Vashon recessional outwash. Vashon recessional outwash was deposited by meltwater streams from a receding glacier and is typically not glacially consolidated. Recessional outwash is suitable for support of paving and lightly-loaded structures with proper preparation. Excavated recessional outwash soils are suitable for reuse in structural fill applications if allowed by project specifications and if adjusted to a suitable moisture content prior to compaction. Vashon Lodgement Till All of our explorations encountered typically medium dense grading to very dense, silty sand with gravel interpreted as Vashon lodgement till. The lodgement till observed in our explorations graded from medium dense to very dense with increasing depth. Lodgement till was deposited at the base of an active ice sheet and was subsequently compacted by the weight of the overlying glacial ice. Lodgement till typically possesses high-strength and low-compressibility attributes that are favorable for support of foundations, floor slabs, and paving with proper preparation. Subsurface Exploration and Renton School District Elementary School No. 16 Preliminary Geotechnical Engineering Report Renton, Washington Project and Site Conditions November 23, 2020 ASSOSCIATED EARTH SCIENCES, INC. CRC/ld - 20180398E002-3 Page 5 Lodgement till is silty and moisture-sensitive. In the presence of moisture contents above the optimum moisture content for compaction purposes, lodgement till can be easily disturbed by vehicles and earthwork equipment. Careful management of moisture-sensitive soils, as recommended in this report, will be needed to reduce the potential for disturbance of wet lodgement till soils and costs associated with repairing disturbed soils. Excavated lodgement till sediments are suitable for reuse in structural fill applications if specifically allowed by project specifications, and if moisture conditions are adjusted to allow compaction to a firm and unyielding condition at the specified level. At the time of exploration the lodgement till sediments were observed to be above optimum moisture content for compaction purposes and would require drying during favorable dry site and weather conditions. Vashon Advance Outwash Transition Sediments Two of the exploration borings completed for this study (EB-13 and EB-14) encountered very dense, weakly to moderately bedded sands with variable silt content and trace gravel interpreted as advance outwash transitional sediments. Advance outwash was deposited by meltwater streams from an advancing ice sheet and was subsequently compacted by the overlying glacial ice. The term “transitional” is interpretative, and indicates that the sediments represent a gradation zone at the base of the lodgement till and the top of the Vashon advance outwash. Advance outwash is suitable for support of structural loads when prepared as recommended in this report and can be an appropriate receptor for stormwater infiltration under some circumstances. Advance outwash may contain a significant fine-grained fraction and can be sensitive to excess moisture during placement in structural fill applications. Reuse of advance outwash in structural fill applications is feasible if specifically allowed by project specifications, and is expected to require drying to achieve moisture contents within 1 to 2 percent of optimum for compaction purposes. 4.2 Regional Geologic and Soil Map Review We reviewed a regional geologic map (J.C. Yount, J.P. Minard, and G.R. Dembroff, 1993, Geologic Map of Surficial Deposits in the Seattle 30’ by 60’ Quadrangle, Washington: U.S. Geological Survey, Open-File Report 93-233, scale 1:100,000). The referenced map indicates that the site is expected to be underlain at shallow depths by Vashon lodgement till. Our on- site explorations and interpretations are generally consistent with the conditions depicted on the referenced published map. Subsurface Exploration and Renton School District Elementary School No. 16 Preliminary Geotechnical Engineering Report Renton, Washington Project and Site Conditions November 23, 2020 ASSOSCIATED EARTH SCIENCES, INC. CRC/ld - 20180398E002-3 Page 6 4.3 Hydrology Groundwater was not encountered in any of the explorations completed for this study at the time of exploration. Although not encountered in our explorations, we expect shallow perched groundwater to be present as “interflow” during the wetter season within existing fill, recessional outwash, and the upper, weathered lodgement till sediments. Interflow occurs when surface water infiltrates down through relatively permeable soils such as the fill and recessional outwash sediments, and becomes trapped or “perched” atop a comparatively very low-permeability barrier such as silty unweathered lodgement till. This perched water may travel laterally above less-permeable strata. The duration and quantity of perched seepage will largely depend on the soil grain-size distribution, topography, seasonal precipitation, on- and off-site land usage, and other factors. 4.4 Laboratory Test Results Two laboratory grain-size analyses were performed in accordance with ASTM procedures on representative selected samples collected during our subsurface exploration for this project. The tests were completed on samples of the lodgement till as part of our stormwater infiltration feasibility assessment. The grain-size analyses test results are included in the Appendix. Subsurface Exploration and Renton School District Elementary School No. 16 Preliminary Geotechnical Engineering Report Renton, Washington Geologic Hazards and Mitigations November 23, 2020 ASSOSCIATED EARTH SCIENCES, INC. CRC/ld - 20180398E002-3 Page 7 II. GEOLOGIC HAZARDS AND MITIGATIONS The following discussion of potential geologic hazards is based on the geologic conditions as observed and discussed herein. 5.0 SLOPE STABILITY HAZARDS AND RECOMMENDED MITIGATION City of Renton critical areas regulations related to steep slopes are contained in Renton Municipal Code (RMC) Section 4-3-050. The City provides an interactive GIS system1 that shows approximate locations of slopes that meet critical slope definitions included in RMC. The RMC provides mechanisms for: • Using site-specific survey data in lieu of City GIS maps to determine the presence of regulated slopes. • Establishing prescriptive buffers for regulated slopes, and reducing prescriptive buffers based on site-specific analysis. • Modification of regulated slopes. 5.1 Sensitive Slopes Based on the site survey, the site contains slopes that meet the RMC definition for Sensitive Slopes. The Sensitive Slopes are located along the west side of the site adjacent to mapped wetlands and are interpreted to be slopes that were created during previous earthwork. RMC does not require a buffer or structure setback for Sensitive Slopes (RMC 4-3-050G). The project as currently proposed may require modification of Sensitive Slopes, which can be allowed under the provisions of RMC 4-3-050J. In our opinion, site grading that is completed in a manner consistent with the recommendations in this report will not result in increased risk of slope instability on or offsite. If construction site Temporary Erosion and Sedimentation Controls (TESCs) are implemented during construction in accordance with local standards of practice, the project as currently proposed will not result in increased risks to the existing wetlands as a result of slope instability or erosion, in our opinion. 5.2 Protected Slopes Based on the site survey, the site does not contain Protected Slopes as defined in RMC 4-3-050G.5.a.ii. 1 https://rp.rentonwa.gov/Html5Public/Index.html?viewer=CORMaps Subsurface Exploration and Renton School District Elementary School No. 16 Preliminary Geotechnical Engineering Report Renton, Washington Geologic Hazards and Mitigations November 23, 2020 ASSOSCIATED EARTH SCIENCES, INC. CRC/ld - 20180398E002-3 Page 8 6.0 SEISMIC HAZARDS AND RECOMMENDED MITIGATION Earthquakes occur in the Puget Sound Lowland. The majority of these events are small and are usually not felt by people. However, large earthquakes do occur as demonstrated by the most recent 6.8-magnitude event on February 28, 2001 near Olympia, Washington, the 1965 6.5-magnitude event, and the 1949 7.2-magnitude event. The 1949 earthquake appears to have been the largest in this area during recorded history. Evaluation of return rates indicates that an earthquake of the magnitude between 5.5 and 6.0 is likely within a given 20-year period. Generally, there are four types of potential geologic hazards associated with large seismic events: 1) surficial ground rupture, 2) seismically induced landslides, 3) liquefaction, and 4) ground motion. The potential for each of these hazards to adversely impact the proposed project is discussed below. 6.1 Surficial Ground Rupture We reviewed a map of possible geologic fault traces on the Washington State Division of Geology and Earth Resources Interactive Geologic Map. The site is located approximately 0.8 miles south of the Seattle Fault Zone, the closest mapped fault zone to the project. The potential for surface rupture due to seismic faulting is low in our opinion due to the distance from the site to mapped faults. 6.2 Seismically Induced Landslides It is our opinion that the potential risk of damage to the proposed development by seismically induced slope failures is low during a design-level seismic event due to the presence of dense and unsaturated native sediments observed at shallow depths below the site. No detailed quantitative assessment of slope stability was completed, and none is warranted for the project as currently proposed, in our opinion. 6.3 Liquefaction Liquefaction is a process through which unconsolidated soil loses strength as a result of vibrations, such as those which occur during a seismic event. During normal conditions, the weight of the soil is supported by both grain-to-grain contacts and by the fluid pressure within the pore spaces of the soil below the water table. Extreme vibratory shaking can disrupt the grain-to-grain contact, increase the pore pressure, and result in a temporary decrease in soil shear strength. The soil is said to be liquefied when nearly all of the weight of the soil is supported by pore pressure alone. Liquefaction can result in deformation of the sediment and settlement of overlying structures. Areas most susceptible to liquefaction include those areas underlain by non-cohesive silt and sand with low relative densities, accompanied by a shallow water table. Subsurface Exploration and Renton School District Elementary School No. 16 Preliminary Geotechnical Engineering Report Renton, Washington Geologic Hazards and Mitigations November 23, 2020 ASSOSCIATED EARTH SCIENCES, INC. CRC/ld - 20180398E002-3 Page 9 A review of the City of Renton’s interactive GIS map indicates that a seismic hazard area exists adjacent to the west of the project. Seismic hazard areas are associated with loose, saturated granular soils that may experience liquefaction during a seismic event. Exploration borings on the west part of the project site near the mapped seismic hazard area offsite encountered very dense Vashon lodgement till near the surface. Lodgement till is not susceptible to liquefaction during a seismic event. The site does not contain subsurface conditions that warrant treatment as seismic hazard critical areas, in our opinion. No quantitative liquefaction analysis was completed for this study, and none is warranted for the project as currently proposed, in our opinion. 6.4 Ground Motion/Seismic Site Class (2015 International Building Code) Structural design of the buildings should follow 2015 International Building Code (IBC) standards. We recommend that the project be designed in accordance with Site Class “C” as defined in IBC Table 20.3-1 of American Society of Civil Engineers (ASCE) 7 – Minimum Design Loads for Buildings and Other Structures. 6.5 Erosion Control The RMC defines a low erosion hazard as an area with soils characterized by the Natural Resource Conservation Service as having slight or moderate erosion potential, and a slope less than 15 percent. A high erosion hazard is defined as having severe or very severe erosion potential, and a slope more than 15 percent. These definitions are incomplete in that the site contains slopes that do not fit either definition. In our opinion the site contains areas that meet the spirit of the definition for low erosion hazard areas. The following recommendations summarize local standards of practice for TESC on construction sites, and are expected to provide adequate mitigation of erosion potential during construction. Project plans should include implementation of temporary erosion controls in accordance with local standards of practice. Control methods should include limiting earthwork to seasonally drier periods, typically April 1 to October 31, use of perimeter silt fences, and straw mulch in exposed areas. Removal of existing vegetation should be limited to those areas that are required to construct the project, and new landscaping and vegetation with equivalent erosion mitigation potential should be established as soon as possible after grading is complete. During construction, surface water should be collected as close as possible to the source to minimize silt entrainment that could require treatment or detention prior to discharge. Timely implementation of permanent drainage control measures should also be a part of the project plans, and will help reduce erosion and generation of silty surface water onsite. Because the site is larger than one acre, testing and reporting of stormwater pH and turbidity will be required during construction. Subsurface Exploration and Renton School District Elementary School No. 16 Preliminary Geotechnical Engineering Report Renton, Washington Preliminary Design Recommendations November 23, 2020 ASSOSCIATED EARTH SCIENCES, INC. CRC/ld - 20180398E002-3 Page 10 III. PRELIMINARY DESIGN RECOMMENDATIONS 7.0 INTRODUCTION Our exploration indicates that from a geotechnical engineering standpoint the proposed school construction project is feasible if the recommendations in this report are implemented. A portion of the site is underlain by existing fill which necessitates remedial preparation prior to constructing new roads and buildings. Observed fill thicknesses at exploration locations are depicted on Figure 2. Existing fill that is expected around former structures and buried utilities will also need to be removed and recompacted at the time of construction. The following report sections provide additional recommendations regarding site preparation, grading, foundations, floor support, drainage, and infiltration feasibility. 8.0 SITE PREPARATION Site preparation of building and paving areas should include removal of all grass, trees, brush, and any other deleterious materials. We recommend that any remaining demolition debris, septic systems, or other similar structures that are discovered be decommissioned and removed in accordance with applicable regulations. Buried utilities should be removed from foundation areas and should be abandoned in place or removed from below planned new paving. Any depressions below planned final grades caused by demolition activities should be backfilled with structural fill, as discussed under the “Structural Fill” section of this report. Existing topsoil and forest duff should be stripped from structural areas. The actual observed in-place depth of grass and topsoil at the exploration locations is presented on the exploration logs in the Appendix. After stripping, remaining roots and stumps should be removed from structural areas. All soils disturbed by stripping and grubbing operations should be recompacted as described below for structural fill. Once stripping is complete, existing fill should be addressed. Existing fill below new buildings should be removed and replaced with structural fill. Below areas of planned paving, existing fill may be left in place if it is free of organic and other deleterious materials, and is compactable to a firm and unyielding condition at 95 percent or more of the modified Proctor maximum dry density (ASTM D-1557). Once excavation to subgrade elevation is complete, the resulting surface should be proof-rolled with a loaded dump truck or other suitable equipment. Any soft, loose, yielding areas or areas exposing excessively organic material should be excavated to exposed suitable bearing soils. The subgrade should then be compacted to at least 95 percent of the modified Proctor maximum dry density, as determined by the ASTM D-1557 test procedure. Structural fill can then be placed to achieve desired grades, if needed. Subsurface Exploration and Renton School District Elementary School No. 16 Preliminary Geotechnical Engineering Report Renton, Washington Preliminary Design Recommendations November 23, 2020 ASSOSCIATED EARTH SCIENCES, INC. CRC/ld - 20180398E002-3 Page 11 8.1 Temporary Cut Slopes In our opinion, stable construction slopes should be the responsibility of the contractor and should be determined during construction. For estimating purposes, however, temporary, unsupported cut slopes can be planned at 1.5H:1V (Horizontal:Vertical) in unsaturated existing fill and recessional outwash. Temporary slopes of 1.0H:1V can be planned in unsaturated lodgement till sediments. These slope angles are for areas where groundwater seepage is not present at the faces of the slopes, which may require temporary dewatering in the form of pumped sumps or other measures. If ground or surface water is present when the temporary excavation slopes are exposed, flatter slope angles may be required. As is typical with earthwork operations, some sloughing and raveling may occur, and cut slopes may have to be adjusted in the field. In addition, WISHA/OSHA regulations should be followed at all times. 8.2 Site Disturbance Most of the on-site soils contain fine-grained material, which makes them moisture-sensitive and subject to disturbance when wet. The contractor must use care during site preparation and excavation operations so that the underlying soils are not softened. If disturbance occurs, the softened soils should be removed and the area brought to grade with structural fill. 8.3 Winter Construction The existing fill material, as well as the lodgement till and recessional outwash sediments contain substantial silt and are considered highly moisture-sensitive. Soils excavated onsite will likely require drying during favorable dry weather conditions to allow their reuse in structural fill applications. Care should be taken to seal all earthwork areas during mass grading at the end of each workday by grading all surfaces to drain and sealing them with a smooth-drum roller. Stockpiled soils that will be reused in structural fill applications should be covered whenever rain is possible. If winter construction is expected, crushed rock fill could be used to provide construction staging areas where exposed soil is present. The stripped subgrade should be observed by the geotechnical engineer, and should then be covered with a geotextile fabric, such as Mirafi 500X or equivalent. Once the fabric is placed, we recommend using a crushed rock fill layer at least 10 inches thick in areas where construction equipment will be used. 9.0 STORMWATER INFILTRATION FEASIBILITY Our explorations completed for this study encountered existing fill and recessional outwash sediments underlain by dense, silty Vashon lodgement till sediments. Existing fill is not a suitable infiltration receptor due to its variable density, silt, and organic content. Two borings Subsurface Exploration and Renton School District Elementary School No. 16 Preliminary Geotechnical Engineering Report Renton, Washington Preliminary Design Recommendations November 23, 2020 ASSOSCIATED EARTH SCIENCES, INC. CRC/ld - 20180398E002-3 Page 12 encountered a thin deposit of recessional outwash at shallow depths. Recessional outwash can be a suitable stormwater infiltration receptor, however the deposits encountered range from 2.5 to 5 feet in thickness and do not appear laterally or vertically extensive enough to support infiltration. Lodgement till is not a suitable infiltration receptor due to its high density and silt content. In our opinion, shallow infiltration at this site using conventional strategies such as infiltrating rain gardens and infiltration vaults is infeasible due to the dense, silty soils at shallow depths across the site. Deep infiltration using strategies such as pit drains or Underground Injection Control (UIC) wells may be feasible, but will require further exploration to determine depth and extent of infiltration receptors at depth. 10.0 STRUCTURAL FILL All references to structural fill in this report refer to subgrade preparation, fill type, placement, and compaction of materials, as discussed in this section. If a percentage of compaction is specified under another section of this report, the value given in that section should be used. For backfill of buried utilities in the right-of-way, the backfill should be placed and compacted in accordance with City of Renton codes and standards. After stripping, planned excavation, and any required overexcavation have been performed to the satisfaction of the geotechnical engineer/engineering geologist, the surface of the exposed ground should be recompacted to a firm and unyielding condition. If the subgrade contains too much moisture, adequate recompaction may be difficult or impossible to obtain, and should probably not be attempted. In lieu of recompaction, the area to receive fill should be blanketed with washed rock or quarry spalls to act as a capillary break between the new fill and the wet subgrade. Where the exposed ground remains soft and further overexcavation is impractical, placement of an engineering stabilization fabric may be necessary to prevent contamination of the free-draining layer by silt migration from below. After recompaction of the exposed ground is tested and approved, or a free-draining rock course is laid, structural fill may be placed to attain desired grades. Structural fill is defined as non-organic soil, acceptable to the geotechnical engineer, placed in maximum 8-inch loose lifts, with each lift being compacted to 95 percent of ASTM D-1557. The top of the compacted fill should extend horizontally outward a minimum distance of 3 feet beyond the locations of the perimeter footings or roadway edges before sloping down at a maximum angle of 2H:1V. The contractor should note that any proposed fill soils should be evaluated by Associated Earth Sciences, Inc. (AESI) prior to their use in fills. This would require that we have a sample of the material at least 72 hours in advance to perform a Proctor test and determine its field compaction standard. Soils in which the amount of fine-grained material (smaller than the No. 200 sieve) is greater than approximately 5 percent (measured on the minus No. 4 sieve size) should be considered Subsurface Exploration and Renton School District Elementary School No. 16 Preliminary Geotechnical Engineering Report Renton, Washington Preliminary Design Recommendations November 23, 2020 ASSOSCIATED EARTH SCIENCES, INC. CRC/ld - 20180398E002-3 Page 13 moisture-sensitive. The existing fill and native soils are estimated to contain more than 5 percent fine-grained material. Existing fill and lodgement till soils are estimated to have substantially more than 5 percent fine-grained material. Use of moisture-sensitive soil in structural fills should be limited to favorable dry weather and dry subgrade conditions. Construction equipment traversing the site when the soils are wet can cause considerable disturbance. If fill is placed during wet weather or if proper compaction cannot be obtained, a select, import material consisting of a clean, free-draining gravel and/or sand should be used. Free-draining fill consists of non-organic soil, with the amount of fine-grained material limited to 5 percent by weight when measured on the minus No. 4 sieve fraction, and at least 25 percent retained on the No. 4 sieve. Excavated existing fill is suitable for reuse in structural fill applications if such reuse is specifically allowed by project plans and specifications, if excessively organic and any other deleterious materials are removed, and moisture content is adjusted to allow compaction to the specified level and to a firm and unyielding condition. The existing fill and native soils we encountered in our explorations ranged in moisture content from moist to wet. In order to reuse excavated on-site soils in structural fill applications, it will be necessary to moisture-condition wet site soils by aeration and drying during favorable dry weather conditions. Alternatives to drying site soils include using imported granular soils suitable for use in structural fill, or treating wet soils with Portland cement. 11.0 FOUNDATIONS The following sections provide two sets of foundation support geotechnical recommendations, one for building foundations and one for stormwater vault foundations. 11.1 Building Foundations Building areas should be prepared in accordance with the “Site Preparation” and “Structural Fill” sections of this report. Conventional continuous spread footings may be used for building support when founded either directly on the undisturbed, dense to very dense natural sediments, or on compacted structural fill over suitable natural sediments. We recommend that an allowable foundation soil bearing pressure of 3,500 pounds per square foot (psf) be utilized for design purposes, including both dead and live loads. An increase of one-third may be used for short-term wind or seismic loading. All footings must penetrate to the prescribed bearing stratum and no footing should be founded in or above loose, organic, or fill soils. 11.2 Stormwater Vault Foundations We anticipate that the project will include a below-grade, cast-in-place stormwater detention vault. Because the detention vault will be constructed below grade and therefore likely below Subsurface Exploration and Renton School District Elementary School No. 16 Preliminary Geotechnical Engineering Report Renton, Washington Preliminary Design Recommendations November 23, 2020 ASSOSCIATED EARTH SCIENCES, INC. CRC/ld - 20180398E002-3 Page 14 any existing weak fill soils, and because the vault has substantial span requirements, a higher allowable foundation soil bearing pressure is appropriate for design of vault foundations. These recommendations are applicable only to the stormwater vault; recommendations presented above should be used for design of building foundations. Conventional continuous spread footings may be used for stormwater vault support when founded on dense to very dense natural sediments. We recommend that an allowable foundation soil bearing pressure of 5,000 psf be utilized for design purposes, including both dead and live loads. An increase of one-third may be used for short-term wind or seismic loading. All footings must penetrate to the prescribed bearing stratum and no footing should be founded in or above loose, organic, or fill soils. 11.3 Conditions, Recommendations, and Settlement Estimate Applicable to All Foundations It should be noted that the area bounded by lines extending downward at 1H:1V from any footing must not intersect another footing or filled area. In addition, a 1.5H:1V line extending down from any footing must not daylight because sloughing or raveling may eventually undermine the footing. Thus, footings should not be placed near the edge of steps or cuts in the bearing soils. Anticipated settlement of footings founded as recommended above should be less than 1 inch with differential settlement one-half of the anticipated total settlement. Most of this movement should occur during initial dead load applications. However, disturbed soil not removed from footing excavations prior to concrete placement could result in increased settlements. All footing areas should be observed by AESI prior to placing concrete to verify that the design bearing capacity of the soils has been attained and that construction conforms to the recommendations contained in this report. Such observation may be required by the City of Renton. A perimeter foundation drain system should be provided as discussed under the “Foundation Drainage Considerations” section of this report. The contractor must use care during site preparation and excavation operations so that the underlying soils are not softened. If disturbance occurs the softened soils should be removed and foundations extended down to competent natural soil. Once the base of the excavation is reached, consideration should be given to “armoring” the exposed subgrade with a thin layer of rock to provide a working surface during foundation construction. We recommend a 6-inch layer of crushed rock for this purpose. 11.4 Foundation Drainage Considerations Building and stormwater vault foundations should be provided with foundation drains. Drains should consist of rigid, perforated, polyvinyl chloride (PVC) pipe placed at footing subgrade elevation and surrounded by washed pea gravel. The drains should be constructed with sufficient gradient to allow gravity discharge away from the proposed structures. Roof and Subsurface Exploration and Renton School District Elementary School No. 16 Preliminary Geotechnical Engineering Report Renton, Washington Preliminary Design Recommendations November 23, 2020 ASSOSCIATED EARTH SCIENCES, INC. CRC/ld - 20180398E002-3 Page 15 surface runoff should not discharge into footing drain systems, but should be handled by a separate, rigid, tightline drain. In planning, exterior grades adjacent to walls should be sloped downward away from the proposed structures to achieve surface drainage. If it is not possible to place a footing drain at the base of the stormwater vault footings, the vault should be constructed to resist lateral pressure imposed by saturated soils and hydrostatic pressure as recommended in Section 13.0 of this report. 12.0 FLOOR SUPPORT After completion of recommendations in the “Site Preparation” section of this report, floor slabs can be supported on medium dense to very dense native soils or on new structural fill. Floor slabs should be cast atop a minimum of 4 inches of clean, washed, crushed rock, or pea gravel to act as a capillary break. Areas of subgrade that are disturbed (loosened) during construction should be compacted to a non-yielding condition prior to placement of capillary break material. Floor slabs should also be protected from dampness by an impervious moisture barrier at least 10 mils thick. The moisture barrier should be placed between the capillary break material and the concrete slab. 13.0 FOUNDATION WALLS 13.1 Building Foundation Walls The following preliminary recommendations may be applied to conventional walls up to 8 feet tall. We should be allowed to offer situation-specific input for taller walls. All backfill behind foundation walls or around foundation units should be placed as per our recommendations for structural fill and as described in this section of the report. Horizontally backfilled walls, which are free to yield laterally at least 0.1 percent of their height, may be designed to resist lateral earth pressure represented by an equivalent fluid equal to 35 pounds per cubic foot (pcf). Fully restrained, horizontally backfilled, rigid walls that cannot yield should be designed for an equivalent fluid of 50 pcf. Walls with sloping backfill up to a maximum gradient of 2H:1V should be designed using an equivalent fluid of 55 pcf for yielding conditions or 75 pcf for fully restrained conditions. If parking areas are adjacent to walls, a surcharge equivalent to 2 feet of soil should be added to the wall height in determining lateral design forces. As required by the 2015 IBC, retaining wall design should include a seismic surcharge pressure in addition to the equivalent fluid pressures presented above. Considering the site soils and the recommended wall backfill materials, we recommend a seismic surcharge pressure of 5H and 10H psf, where H is the wall height in feet for the “active” and “at-rest” loading conditions, respectively. The seismic surcharge should be modeled as a rectangular distribution with the resultant applied at the midpoint of the walls. Subsurface Exploration and Renton School District Elementary School No. 16 Preliminary Geotechnical Engineering Report Renton, Washington Preliminary Design Recommendations November 23, 2020 ASSOSCIATED EARTH SCIENCES, INC. CRC/ld - 20180398E002-3 Page 16 The lateral pressures presented above are based on the conditions of a uniform backfill consisting of excavated on-site soils, or imported structural fill compacted to 90 percent of ASTM D-1557. A higher degree of compaction is not recommended, as this will increase the pressure acting on the walls. A lower compaction may result in settlement of the slab-on-grade or other structures supported above the walls. Thus, the compaction level is critical and must be tested by our firm during placement. Surcharges from adjacent footings or heavy construction equipment must be added to the above values. Perimeter footing drains should be provided for all retaining walls, as discussed under the “Drainage Considerations” section of this report. It is imperative that proper drainage be provided so that hydrostatic pressures do not develop against the walls. This would involve installation of a minimum 1-foot-wide blanket drain to within 1 foot of finish grade for the full wall height using imported, washed gravel against the walls. 13.2 Stormwater Vault Foundation Walls Stormwater vaults may be designed in accordance with lateral earth pressure and drainage recommendations as described above for building walls, except as follows: • If it is not possible to place a footing drain at the base of the detention vault, we recommend installing a footing drain as deep as possible depending on footing drain discharge options that are available. • Any location where vault walls extend below drain elevation should be structurally designed for saturated conditions below the elevation of the drain. • Under saturated conditions, active lateral earth pressure should be assumed to be 80 pcf expressed as an equivalent fluid, and at-rest (restrained) lateral earth pressure should be assumed to be 90 pcf. • For detention vault drainage, the use of composite drain mats such as Miradrain is acceptable in lieu of the washed rock drainage blanket described in Section 11.4 of this report. Drainage mats should be continuous with and freely communicate with the footing drain, and should be incorporated and installed in accordance with the manufacturer’s recommendations. 13.3 Passive Resistance and Friction Factors Lateral loads can be resisted by friction between the foundation and the natural soils or supporting structural fill soils, and by passive earth pressure acting on the buried portions of the foundations. The foundations must be backfilled with structural fill and compacted to at least 95 percent of the maximum dry density to achieve the passive resistance provided below. We recommend the following allowable design parameters: Subsurface Exploration and Renton School District Elementary School No. 16 Preliminary Geotechnical Engineering Report Renton, Washington Preliminary Design Recommendations November 23, 2020 ASSOSCIATED EARTH SCIENCES, INC. CRC/ld - 20180398E002-3 Page 17 • Passive equivalent fluid = 250 pcf • Coefficient of friction = 0.30 14.0 PAVEMENT RECOMMENDATIONS We anticipate that project plans may include construction of new paved parking lots and access roads. At this time we do not anticipate that new paving will be completed on public streets. If new paving is planned on public streets we should be allowed to make situation-specific paving recommendations. After the area to be paved is stripped, any organic soils are removed, and the soils are recompacted, the area should be proof-rolled with a loaded truck under the observation of AESI. Any soft, wet, organic, or yielding areas should be repaired as recommended during construction. If warranted, engineering stabilization fabric, such as Mirafi 500X (or equivalent), should be placed over the subgrade with the edges overlapped in accordance with the manufacturer’s recommendations. Following subgrade preparation, clean, free-draining structural fill should be placed over the fabric and compacted to 95 percent of ASTM D-1557. Where fabric is exposed, spreading should be performed such that the dozer remains on the fill material and is not allowed to operate on uncovered fabric. When 12 inches of fill has been placed, the fabric should be proof-rolled with a loaded dump truck to pretension the fabric and identify soft spots in the fill. Upon completing the proof-rolling operation, additional structural fill should be placed and compacted to attain desired grades. For driveways and private paving serving passenger cars, we recommend a paving section consisting of 3 inches of Class ½-inch HMA underlain by 4 inches of crushed surfacing base course (CSBC). Alternatively asphalt treated base (ATB) or Class ¾-inch HMA could be used for construction access followed by repair of any construction damage and final surfacing. If this alternative is used, we recommend a minimum of 2 inches of CSBC to serve as a working surface and a minimum of 3 inches of ATB. Final surfacing should consist of 2 inches of Class ½-inch HMA after any construction damage has been repaired. Paving for heavy traffic areas such as bus lanes, fire lanes, and access for garbage and food service trucks should consist of 4 inches of Class ½-inch HMA above 6 inches of crushed rock base. If an ATB section is desired, we recommend a 2-inch-thick working surface of crushed rock, topped by 4 inches of ATB and 3 inches of Class ½-inch HMA. 15.0 PROJECT DESIGN AND CONSTRUCTION MONITORING Our report is preliminary since project plans were in development at the time this report was prepared. We recommend that we be allowed to review project plans when they are completed and to revise the recommendations presented in this report as needed. Subsurface Exploration and Renton School District Elementary School No. 16 Preliminary Geotechnical Engineering Report Renton, Washington Preliminary Design Recommendations November 23, 2020 ASSOSCIATED EARTH SCIENCES, INC. CRC/ld - 20180398E002-3 Page 18 We are also available to provide geotechnical engineering and testing services during construction. The integrity of the foundation system depends on proper site preparation and construction procedures. In addition, engineering decisions may have to be made in the field in the event that variations in subsurface conditions become apparent. Construction monitoring services are not part of our currently approved scope of work. We have enjoyed working with you on this study and are confident that these recommendations will aid in the successful completion of your project. If you should have any questions or require further assistance please do not hesitate to call. Sincerely, ASSOCIATED EARTH SCIENCES, INC. Kirkland, Washington ______________________________ Charles R. Christopher, G.I.T. Senior Staff Geologist ______________________________ Bruce W. Guenzler, L.E.G. Kurt D. Merriman, P.E. Senior Associate Geologist Senior Principal Engineer Attachments: Figure 1: Vicinity Map Figure 2: Site and Exploration Plan Figure 3: Existing Site and Exploration Plan Appendix: Exploration Logs Laboratory Testing Results APPENDIX Exploration Logs Laboratory Testing Results 142850 3550/3" 50/1" S-1 S-2 S-3 Bottom of exploration boring at 12.6 feetNo groundwater encountered. Grass / Topsoil Vashon Lodgement Till Moist, gray with some oxidation, very silty, gravelly, fine to medium SAND;unsorted (SM). Becomes gray. No recovery due to rock. 1 of 1 NAVD 88 DV2" OD Split Spoon Sampler (SPT) 3" OD Split Spoon Sampler (D & M)Water LevelProject Name CJKWater Level ()Approved by: 30 Blows/Foot Samples~426 5 10 15 20 EB-1 Ring Sample No RecoveryGraphic 10 Other TestsHole Diameter (in) DESCRIPTION Driller/Equipment Blows/6"Exploration Boring Water Level at time of drilling (ATD) Renton School District Elementary School No. 16 M - Moisture Project Number 20 Renton, WA Date Start/Finish CompletionLocation Sheet Depth (ft)S T Exploration Number20180398E002 8/22/18,8/22/18 Logged by: Shelby Tube Sample 140# / 30"Geologic Drill / Mini Track Well Ground Surface Elevation (ft) Grab SampleSymbol 5 inches 40 Datum Hammer Weight/Drop Sampler Type (ST):AESIBOR 20180398E002.GPJ November 18, 202078 5050/3" 5050/1" 194240 2250/6" 382938 S-1 S-2 S-3 Bottom of exploration boring at 14 feetNo groundwater encountered. Grass / Topsoil Vashon Lodgement Till Moist, oxidized gray, very silty, gravelly, fine to medium SAND; unsorted(SM). Becomes gray. Becomes very moist. 1 of 1 NAVD 88 DV2" OD Split Spoon Sampler (SPT) 3" OD Split Spoon Sampler (D & M)Water LevelProject Name CJKWater Level ()Approved by: 30 Blows/Foot Samples~422 5 10 15 20 EB-2 Ring Sample No RecoveryGraphic 10 Other TestsHole Diameter (in) DESCRIPTION Driller/Equipment Blows/6"Exploration Boring Water Level at time of drilling (ATD) Renton School District Elementary School No. 16 M - Moisture Project Number 20 Renton, WA Date Start/Finish CompletionLocation Sheet Depth (ft)S T Exploration Number20180398E002 8/22/18,8/22/18 Logged by: Shelby Tube Sample 140# / 30"Geologic Drill / Mini Track Well Ground Surface Elevation (ft) Grab SampleSymbol 5 inches 40 Datum Hammer Weight/Drop Sampler Type (ST):AESIBOR 20180398E002.GPJ November 18, 202082 5050/6" 67 435 50/6" 202640 S-1 S-2 S-3 Bottom of exploration boring at 14 feetNo groundwater encountered. Grass / Topsoil Fill Slightly moist to dry, brown to dark brown, very silty, fine SAND, tracegravel, trace charcoal and other organics (SM). Moist, grayish brown, silty, fine to medium SAND, some gravel (SM). Vashon Lodgement Till Driller notes hard drilling at 7 feet. Moist, gray, very silty, fine to medium SAND, some gravel; unsorted (SM). Moist, oxidized gray, very silty, fine SAND, trace gravel; unsorted (SM). 1 of 1 NAVD 88 DV2" OD Split Spoon Sampler (SPT) 3" OD Split Spoon Sampler (D & M)Water LevelProject Name CJKWater Level ()Approved by: 30 Blows/Foot Samples~414 5 10 15 20 EB-3 Ring Sample No RecoveryGraphic 10 Other TestsHole Diameter (in) DESCRIPTION Driller/Equipment Blows/6"Exploration Boring Water Level at time of drilling (ATD) Renton School District Elementary School No. 16 M - Moisture Project Number 20 Renton, WA Date Start/Finish CompletionLocation Sheet Depth (ft)S T Exploration Number20180398E002 8/22/18,8/22/18 Logged by: Shelby Tube Sample 140# / 30"Geologic Drill / Mini Track Well Ground Surface Elevation (ft) Grab SampleSymbol 5 inches 40 Datum Hammer Weight/Drop Sampler Type (ST):AESIBOR 20180398E002.GPJ November 18, 202088 5050/6" 66 8914 131517 222226 S-1 S-2 S-3 Bottom of exploration boring at 14 feetNo groundwater encountered. Grass / Topsoil Fill Moist, oxidized gray, very silty, fine to medium SAND, some gravel, tracecharcoal (SM). Vashon Lodgement Till Driller notes hard drilling at 7 feet. Moist, gray, very silty, fine to medium SAND, some gravel; unsorted (SM). As above. 1 of 1 NAVD 88 DV2" OD Split Spoon Sampler (SPT) 3" OD Split Spoon Sampler (D & M)Water LevelProject Name CJKWater Level ()Approved by: 30 Blows/Foot Samples~429 5 10 15 20 EB-4 Ring Sample No RecoveryGraphic 10 Other TestsHole Diameter (in) DESCRIPTION Driller/Equipment Blows/6"Exploration Boring Water Level at time of drilling (ATD) Renton School District Elementary School No. 16 M - Moisture Project Number 20 Renton, WA Date Start/Finish CompletionLocation Sheet Depth (ft)S T Exploration Number20180398E002 8/22/18,8/22/18 Logged by: Shelby Tube Sample 140# / 30"Geologic Drill / Mini Track Well Ground Surface Elevation (ft) Grab SampleSymbol 5 inches 40 Datum Hammer Weight/Drop Sampler Type (ST):AESIBOR 20180398E002.GPJ November 18, 20202323 3232 4848 161920 131717 182533 S-1 S-2 S-3 Bottom of exploration boring at 14 feetNo groundwater encountered. Grass / Topsoil Vashon Lodgement Till Slightly moist, oxidized gray, very silty, fine SAND, some gravel; unsorted(SM). Becomes moist to very moist, gray. Becomes moist. 1 of 1 NAVD 88 DV2" OD Split Spoon Sampler (SPT) 3" OD Split Spoon Sampler (D & M)Water LevelProject Name CJKWater Level ()Approved by: 30 Blows/Foot Samples~434 5 10 15 20 EB-5 Ring Sample No RecoveryGraphic 10 Other TestsHole Diameter (in) DESCRIPTION Driller/Equipment Blows/6"Exploration Boring Water Level at time of drilling (ATD) Renton School District Elementary School No. 16 M - Moisture Project Number 20 Renton, WA Date Start/Finish CompletionLocation Sheet Depth (ft)S T Exploration Number20180398E002 8/22/18,8/22/18 Logged by: Shelby Tube Sample 140# / 30"Geologic Drill / Mini Track Well Ground Surface Elevation (ft) Grab SampleSymbol 5 inches 40 Datum Hammer Weight/Drop Sampler Type (ST):AESIBOR 20180398E002.GPJ November 18, 20203939 3434 58 71012 2350/4" S-1 S-2 Bottom of exploration boring at 10.8 feetNo groundwater encountered. Grass / Topsoil Vashon Lodgement Till Moist to very moist, gray with some oxidation, very silty, fine to mediumSAND, some gravel; unsorted (SM). Contains trace to some coarse sand (SM). 1 of 1 NAVD 88 DV2" OD Split Spoon Sampler (SPT) 3" OD Split Spoon Sampler (D & M)Water LevelProject Name CJKWater Level ()Approved by: 30 Blows/Foot Samples~435 5 10 15 20 EB-6 Ring Sample No RecoveryGraphic 10 Other TestsHole Diameter (in) DESCRIPTION Driller/Equipment Blows/6"Exploration Boring Water Level at time of drilling (ATD) Renton School District Elementary School No. 16 M - Moisture Project Number 20 Renton, WA Date Start/Finish CompletionLocation Sheet Depth (ft)S T Exploration Number20180398E002 8/22/18,8/22/18 Logged by: Shelby Tube Sample 140# / 30"Geologic Drill / Mini Track Well Ground Surface Elevation (ft) Grab SampleSymbol 5 inches 40 Datum Hammer Weight/Drop Sampler Type (ST):AESIBOR 20180398E002.GPJ November 18, 20202222 5050/4" 193432 101931 S-1 S-2 Bottom of exploration boring at 11.5 feetNo groundwater encountered. Grass / Topsoil Vashon Lodgement Till Moist, gray, silty, gravelly, fine to medium SAND; unsorted (SM). As above. 1 of 1 NAVD 88 DV2" OD Split Spoon Sampler (SPT) 3" OD Split Spoon Sampler (D & M)Water LevelProject Name CJKWater Level ()Approved by: 30 Blows/Foot Samples~433 5 10 15 20 EB-7 Ring Sample No RecoveryGraphic 10 Other TestsHole Diameter (in) DESCRIPTION Driller/Equipment Blows/6"Exploration Boring Water Level at time of drilling (ATD) Renton School District Elementary School No. 16 M - Moisture Project Number 20 Renton, WA Date Start/Finish CompletionLocation Sheet Depth (ft)S T Exploration Number20180398E002 8/22/18,8/22/18 Logged by: Shelby Tube Sample 140# / 30"Geologic Drill / Mini Track Well Ground Surface Elevation (ft) Grab SampleSymbol 5 inches 40 Datum Hammer Weight/Drop Sampler Type (ST):AESIBOR 20180398E002.GPJ November 18, 202066 3364 50/4" 50/1" S-1 S-2 Bottom of exploration boring at 10.1 feetNo groundwater encountered. Grass / Topsoil Vashon Lodgement Till Moist, gray, very silty, fine to medium SAND, some gravel; unsorted (SM). Poor recovery due to gravel. 1 of 1 NAVD 88 DV2" OD Split Spoon Sampler (SPT) 3" OD Split Spoon Sampler (D & M)Water LevelProject Name CJKWater Level ()Approved by: 30 Blows/Foot Samples~414 5 10 15 20 EB-8 Ring Sample No RecoveryGraphic 10 Other TestsHole Diameter (in) DESCRIPTION Driller/Equipment Blows/6"Exploration Boring Water Level at time of drilling (ATD) Renton School District Elementary School No. 16 M - Moisture Project Number 20 Renton, WA Date Start/Finish CompletionLocation Sheet Depth (ft)S T Exploration Number20180398E002 8/22/18,8/22/18 Logged by: Shelby Tube Sample 140# / 30"Geologic Drill / Mini Track Well Ground Surface Elevation (ft) Grab SampleSymbol 5 inches 40 Datum Hammer Weight/Drop Sampler Type (ST):AESIBOR 20180398E002.GPJ November 18, 20205050/4" 5050/1" 232 121822 141828 50/6" S-1 S-2 S-3 S-4 Bottom of exploration boring at 10.5 feetNo groundwater encountered. Sod / Topsoil - ~4 inches Vashon Lodgement TillMoist, orangish brown, silty, fine SAND, trace gravel; frequent organics(charcoal/rootlets) (SM). Moist, orangish gray to brownish gray, silty, fine SAND, trace gravel;unsorted; diamict-like appearance; occasional organics (rootlets) (SM). Moist, brownish gray, silty, fine SAND, trace gravel; rare organics; gravelsare subrounded, some broken; unsorted; diamict-like appearance (SM). Driller notes hard drilling. Moist, gray, silty, fine SAND, trace gravel; gravels are fine and subrounded;unsorted; diamict-like appearance (SM). 1 of 1 NAVD 88 ALG2" OD Split Spoon Sampler (SPT) 3" OD Split Spoon Sampler (D & M)Water LevelProject Name JHSWater Level ()Approved by: 30 Blows/Foot Samples~436 5 10 15 20 EB-9 Ring Sample No RecoveryGraphic 10 Other TestsHole Diameter (in) DESCRIPTION Driller/Equipment Blows/6"Exploration Boring Water Level at time of drilling (ATD) Renton School District Elementary School No. 16 M - Moisture Project Number 20 Renton, WA Date Start/Finish CompletionLocation Sheet Depth (ft)S T Exploration Number20180398E002 9/27/19,9/27/19 Logged by: Shelby Tube Sample 140# / 30"Boretec / Rubber-Track Volvo EC55C HSA Well Ground Surface Elevation (ft) Grab SampleSymbol 8 inches 40 Datum Hammer Weight/Drop Sampler Type (ST):AESIBOR 20180398E002.GPJ November 18, 202055 4040 4646 5050/6" 456 2310 4050/6" 192050/5" 50/5" S-1 S-2 S-3 S-4 S-5 Bottom of exploration boring at 15.4 feetNo groundwater encountered. Sod / Topsoil - 4 inches Fill / DuffMoist, orangish gray, silty, fine SAND, trace gravel; occasional organics(charcoal/rootlets); unsorted (SM). Vashon Recessional Outwash Slightly moist, brownish gray, fine SAND, some silt, trace gravel;occasional organics (charcoal/roots) (SP-SM). Vashon Lodgement Till Slightly moist, brownish gray, fine SAND, some silt, trace gravel; rareorganics (rootlets); unsorted (SP-SM). Hard drilling/rig chatter at 9 feet. Moist, brownish gray, fine to medium SAND, some silt to silty, trace gravel;weakly stratified zones of silty sand, unsorted, diamict-like and mediumsand, some silt (SM/SP-SM). Hard drilling/rig chatter at 12 feet. Moist to very moist, fine to medium SAND, some silt to silty, trace gravel;gravels are subrounded; faintly gradationally stratified (SP-SM/SM). 1 of 1 NAVD 88 ALG2" OD Split Spoon Sampler (SPT) 3" OD Split Spoon Sampler (D & M)Water LevelProject Name JHSWater Level ()Approved by: 30 Blows/Foot Samples~431 5 10 15 20 EB-10 Ring Sample No RecoveryGraphic 10 Other TestsHole Diameter (in) DESCRIPTION Driller/Equipment Blows/6"Exploration Boring Water Level at time of drilling (ATD) Renton School District Elementary School No. 16 M - Moisture Project Number 20 Renton, WA Date Start/Finish CompletionLocation Sheet Depth (ft)S T Exploration Number20180398E002 9/27/19,9/27/19 Logged by: Shelby Tube Sample 140# / 30"Boretec / Rubber-Track Volvo EC55C HSA Well Ground Surface Elevation (ft) Grab SampleSymbol 8 inches 40 Datum Hammer Weight/Drop Sampler Type (ST):AESIBOR 20180398E002.GPJ November 18, 20201111 1313 90 5050/5" 5050/5" 221 5810 9910 2850/6" 4050/5" S-1 S-2 S-3 S-4 S-5 Bottom of exploration boring at 15.9 feetNo groundwater encountered. Sod / Topsoil - 4 inches Forest DuffMoist, orangish brown, silty, fine SAND, trace gravel; frequent organics(charcoal/rootlets) (SM). Vashon Recessional Outwash Moist, brownish gray with bands of iron oxide staining, fine to mediumSAND, some silt, trace gravel; rare organics (roots); gradationally stratified(SP-SM). As above; gradationally stratified (SP-SM). Vashon Lodgement Till Hard drilling/rig chatter at 7 feet. Moist, gray, silty, fine SAND, some gravel, some medium to coarse sand;unsorted; diamict-like appearance (SM). Hard drilling/rig chatter at 13 feet. As above; gravels are fine to coarse, broken, and weathered; unsorted;diamict-like appearance (SM). 1 of 1 NAVD 88 ALG2" OD Split Spoon Sampler (SPT) 3" OD Split Spoon Sampler (D & M)Water LevelProject Name JHSWater Level ()Approved by: 30 Blows/Foot Samples~409 5 10 15 20 EB-11 Ring Sample No RecoveryGraphic 10 Other TestsHole Diameter (in) DESCRIPTION Driller/Equipment Blows/6"Exploration Boring Water Level at time of drilling (ATD) Renton School District Elementary School No. 16 M - Moisture Project Number 20 Renton, WA Date Start/Finish CompletionLocation Sheet Depth (ft)S T Exploration Number20180398E002 9/27/19,9/27/19 Logged by: Shelby Tube Sample 140# / 30"Boretec / Rubber-Track Volvo EC55C HSA Well Ground Surface Elevation (ft) Grab SampleSymbol 8 inches 40 Datum Hammer Weight/Drop Sampler Type (ST):AESIBOR 20180398E002.GPJ November 18, 202033 1818 1919 78 5050/5" 345 132940 222948 4050/4" 50/3" S-1 S-2 S-3 S-4 S-5 Bottom of exploration boring at 15.3 feetNo groundwater encountered. Fill Moist, light brown to dark brown, silty, fine SAND, some gravel; abundantorganics (rootlets/wood debris); poor recovery (SM). Vashon Lodgement Till Slightly moist to moist, brownish gray with mottled iron oxide staining, silty,fine SAND, some gravel; gravels are fine to coarse, weathered, andbroken; unsorted; diamict-like appearance (SM). As above; less iron oxide mottling; some coarse sand; broken gravelsthroughout (SM). Hard drilling/rig chatter at 7 feet. Slightly moist, brownish gray, silty, fine SAND, some gravel; section (~2inches thick) of broken gravel (SM). Hard drilling at 11.5 feet. Rig chatter at 12.5 feet. Moist, brownish gray, silty, fine SAND, some gravel; broken gravelthroughout; unsorted; diamict like (SM). 1 of 1 NAVD 88 ALG2" OD Split Spoon Sampler (SPT) 3" OD Split Spoon Sampler (D & M)Water LevelProject Name JHSWater Level ()Approved by: 30 Blows/Foot Samples~425 5 10 15 20 EB-12 Ring Sample No RecoveryGraphic 10 Other TestsHole Diameter (in) DESCRIPTION Driller/Equipment Blows/6"Exploration Boring Water Level at time of drilling (ATD) Renton School District Elementary School No. 16 M - Moisture Project Number 20 Renton, WA Date Start/Finish CompletionLocation Sheet Depth (ft)S T Exploration Number20180398E002 9/27/19,9/27/19 Logged by: Shelby Tube Sample 140# / 30"Boretec / Rubber-Track Volvo EC55C HSA Well Ground Surface Elevation (ft) Grab SampleSymbol 8 inches 40 Datum Hammer Weight/Drop Sampler Type (ST):AESIBOR 20180398E002.GPJ November 18, 202099 69 77 5050/4" 5050/3" 321 2915 81116 101516 50/6" 4050/5" S-1 S-2 S-3 S-4 S-5 S-6 Bottom of exploration boring at 20.9 feetNo groundwater encountered. Fill Moist, orangish brown to dark brown, silty, fine to medium SAND, somegravel; frequent organics (charcoal/rootlets) (SM). Upper 6 inches: very moist, brown to grayish brown, silty, fine to mediumSAND, some gravel (SM). Vashon Lodgement Till Lower 6 inches: moist, brownish gray with bands of iron oxide staining,silty, fine SAND, trace to some gravel; unsorted; diamict-like (SM), Upper 6 inches: as above (SM). Lower 6 inches: becomes moist, gray to greenish gray, silty, fine SAND,some gravel; gravels are fine to coarse, weathered, and broken (SM). Upper 4 inches: as above; moderate to strong organic/petrochemical odor(SM).Moist, brownish gray with mottled iron oxide staining, silty, medium SAND,some gravel, some purple gravel (rhyolite?); unsorted; diamict-like (SM). Hard drilling/rig chatter at 12.5 feet. Moist, brownish gray, silty, fine to medium SAND, some gravel; unsorted;diamict-like appearance; gravels are subrounded, some broken, andweathered (SM). Upper 6 in: moist, brownish gray, interbedded silty, fine SAND (SM) andmedium SAND, trace silt (SP). At 20.5 ft: Vashon Lodgement Till / Vashon Advance Outwash ? - Lower6 in: moist to very moist, brownish gray, fine to medium SAND, some silt,trace gravel (SP-SM); moderately bedded with occasional interbeds (~1/2inch thick) of silty fine sand (SM). 1 of 1 NAVD 88 ALG2" OD Split Spoon Sampler (SPT) 3" OD Split Spoon Sampler (D & M)Water LevelProject Name JHSWater Level ()Approved by: 30 Blows/Foot Samples~424 5 10 15 20 EB-13 Ring Sample No RecoveryGraphic 10 Other TestsHole Diameter (in) DESCRIPTION Driller/Equipment Blows/6"Exploration Boring Water Level at time of drilling (ATD) Renton School District Elementary School No. 16 M - Moisture Project Number 20 Renton, WA Date Start/Finish CompletionLocation Sheet Depth (ft)S T Exploration Number20180398E002 9/27/19,9/27/19 Logged by: Shelby Tube Sample 140# / 30"Boretec / Rubber-Track Volvo EC55C HSA Well Ground Surface Elevation (ft) Grab SampleSymbol 8 inches 40 Datum Hammer Weight/Drop Sampler Type (ST):AESIBOR 20180398E002.GPJ November 18, 202033 2424 2727 3131 5050/6" 5050/5" 322 102022 91523 4050/4" 50/6" 171340 S-1 S-2 S-3 S-4 S-5 S-6 Bottom of exploration boring at 21.5 feetNo groundwater encountered. Sod / Topsoil - 4 inches FillMoist, orangish brown, silty, fine SAND, trace gravel; frequent organics(charcoal/rootlets) (SM). Vashon Lodgement Till Slightly moist, brownish gray with mottled iron oxide staining, silty, fineSAND, some gravel; massive; unsorted; gravels are fine to coarse, broken,and weathered (SM). Hard drilling at 4 feet. Moist, brownish gray with mottled iron oxide staining, silty, fine SAND,some gravel; unsorted; diamict-like; gravels are broken and weathered(SM). Slightly moist to moist, brownish gray, silty, fine to medium SAND, somegravel; gravels are broken and weathered; section (~2 inches thick) ofbroken gravel; less silt and moisture with depth (SM).Hard drilling/rig chatter at 11 feet. Moist, brownish gray, silty, fine to medium SAND, trace to some gravel;gravels are broken throughout; unsorted; diamict-like appearance (SM). Hard drilling/rig chatter at 16 feet. Upper 5 inches: moist, brownish gray, silty, fine SAND, trace gravel;unsorted; diamict-like (SM). At 20.4 ft: Vashon Advance Outwash / Vashon Lodgement Till ? -Becomes moist to very moist, brownish gray, interbedded, silty, fine SAND(SM) and fine to medium SAND, some silt (SP-SM); moderatelybedded in layers (~1/2 inch thick); higher moisture in less silty interbeds. 1 of 1 NAVD 88 ALG2" OD Split Spoon Sampler (SPT) 3" OD Split Spoon Sampler (D & M)Water LevelProject Name JHSWater Level ()Approved by: 30 Blows/Foot Samples~421 5 10 15 20 EB-14 Ring Sample No RecoveryGraphic 10 Other TestsHole Diameter (in) DESCRIPTION Driller/Equipment Blows/6"Exploration Boring Water Level at time of drilling (ATD) Renton School District Elementary School No. 16 M - Moisture Project Number 20 Renton, WA Date Start/Finish CompletionLocation Sheet Depth (ft)S T Exploration Number20180398E002 9/27/19,9/27/19 Logged by: Shelby Tube Sample 140# / 30"Boretec / Rubber-Track Volvo EC55C HSA Well Ground Surface Elevation (ft) Grab SampleSymbol 8 inches 40 Datum Hammer Weight/Drop Sampler Type (ST):AESIBOR 20180398E002.GPJ November 18, 202044 4242 3838 5050/4" 5050/6" 53 344 41513 568 34150/3" 274750/5" 151732 S-1 S-2 S-3 S-4 S-5 S-6 Bottom of exploration boring at 16.5 feetNo groundwater encountered. Topsoil - 6 inchesMoist, dark brown, sandy, SILT; frequent rootlets/organics (ML). FillLower 6 inches: moist, orangish brown with moderate oxidation, mostly fineto medium SAND, some silt; occasional mica, charcoal, and rootlets;discontinuous lens of dark brown, sandy, silt (SP-ML). Upper 6 inches: as above; becomes heavily oxidized; silty; moderate fineorganics/rootlets (SM).Lower 12 inches: moist, grayish brown with slight to moderate oxidationstaining, silty, fine SAND, some gravel; one broken gravel in sampler;unsorted (SM). Moist to very moist, brownish gray, silty, fine SAND, some gravel; scatteredclasts of brown, sandy, silt with moderate oxidation; unsorted (SM-ML). Vashon Lodgement TillIncreased drilling difficulty at 6.5 feet. Moist, brownish gray with slight oxidation, silty, fine to medium SAND,some gravel; becomes very moist within sandier zones; unsorted (SM). As above; moist. As above. 1 of 1 NAVD 88 CRC2" OD Split Spoon Sampler (SPT) 3" OD Split Spoon Sampler (D & M)Water LevelProject Name JHSWater Level ()Approved by: 30 Blows/Foot Samples~433 5 10 15 20 EB-15 Ring Sample No RecoveryGraphic 10 Other TestsHole Diameter (in) DESCRIPTION Driller/Equipment Blows/6"Exploration Boring Water Level at time of drilling (ATD) Renton School District Elementary School No. 16 M - Moisture Project Number 20 Renton, WA Date Start/Finish CompletionLocation Sheet Depth (ft)S T Exploration Number20180398E002 10/6/20,10/6/20 Logged by: Shelby Tube Sample 140# / 30"Advance Drill Tech / D50 Mobile Track Rig Well Ground Surface Elevation (ft) Grab SampleSymbol 8 inches 40 Datum Hammer Weight/Drop Sampler Type (ST):AESIBOR 20180398E002.GPJ November 18, 202088 2828 1414 5050/3" 5050/5" 4949 4514 51018 154135 4150/5" 50/6" S-1 S-2 S-3 S-4 S-5 Bottom of exploration boring at 10.5 feetNo groundwater encountered. Topsoil - 12 inchesMoist to very moist, dark brown,sandy, SILT; frequent fine organic debris,roots, and rootlets (ML). Vashon Lodgement TillLower 12 inches: moist, brown with moderate oxidation, silty, fine SAND,trace gravel; occasional rootlets (SM).Grinding and increased drilling difficulty at 2 feet.Moist, grayish brown with slight oxidation, silty, fine to medium SAND,some gravel to gravelly; contains sandier zones; unsorted (SM). As above; becomes brownish gray; lack of sandier zones; blowcounts areslightly overstated (SM).Bouncing on rock at 5 feet. Moist, brownish gray, silty, fine to medium SAND, some gravel; unsorted(SM). As above. 1 of 1 NAVD 88 CRC2" OD Split Spoon Sampler (SPT) 3" OD Split Spoon Sampler (D & M)Water LevelProject Name JHSWater Level ()Approved by: 30 Blows/Foot Samples~428 5 10 15 20 EB-16 Ring Sample No RecoveryGraphic 10 Other TestsHole Diameter (in) DESCRIPTION Driller/Equipment Blows/6"Exploration Boring Water Level at time of drilling (ATD) Renton School District Elementary School No. 16 M - Moisture Project Number 20 Renton, WA Date Start/Finish CompletionLocation Sheet Depth (ft)S T Exploration Number20180398E002 10/6/20,10/6/20 Logged by: Shelby Tube Sample 140# / 30"Advance Drill Tech / D50 Mobile Track Rig Well Ground Surface Elevation (ft) Grab SampleSymbol 8 inches 40 Datum Hammer Weight/Drop Sampler Type (ST):AESIBOR 20180398E002.GPJ November 18, 20201919 2828 76 5050/5" 5050/6" 345 101817 113848 223234 50/3" 503636 S-1 S-2 S-3 S-4 S-5 S-6 Bottom of exploration boring at 16.5 feetNo groundwater encountered. Topsoil - 6 inches Vashon Lodgement TillLower 6 inches: moist, brown with moderate to heavy oxidation, silty, fineto medium SAND, trace gravel; moderate rootlets/charcoal (SM).Drilling difficulty and grinding increases at 1.5 feet. Moist, grayish brown with slight to moderate oxidation, silty, fine to mediumSAND, trace gravel; unsorted (SM). Drilling difficulty increases. Moist, brownish gray with slight oxidation, silty, fine to medium SAND,some gravel; unsorted; broken gravel within sampler; blowcounts areslightly overstated (SM). As above. As above; poor recovery; bouncing on rock; blowcounts overstated. As above; broken gravel within sampler; blowcounts slightly overstated. 1 of 1 NAVD 88 CRC2" OD Split Spoon Sampler (SPT) 3" OD Split Spoon Sampler (D & M)Water LevelProject Name JHSWater Level ()Approved by: 30 Blows/Foot Samples~428 5 10 15 20 EB-17 Ring Sample No RecoveryGraphic 10 Other TestsHole Diameter (in) DESCRIPTION Driller/Equipment Blows/6"Exploration Boring Water Level at time of drilling (ATD) Renton School District Elementary School No. 16 M - Moisture Project Number 20 Renton, WA Date Start/Finish CompletionLocation Sheet Depth (ft)S T Exploration Number20180398E002 10/6/20,10/6/20 Logged by: Shelby Tube Sample 140# / 30"Advance Drill Tech / D50 Mobile Track Rig Well Ground Surface Elevation (ft) Grab SampleSymbol 8 inches 40 Datum Hammer Weight/Drop Sampler Type (ST):AESIBOR 20180398E002.GPJ November 18, 202099 2525 86 66 5050/3" 72 345 111336 192131 124450/5" 4350/5" 1550/5" S-1 S-2 S-3 S-4 S-5 S-6 Bottom of exploration boring at 16 feetNo groundwater encountered. Topsoil - 6 inches FillLower 6 inches: moist, brown with slight oxidation, silty, fine SAND;occasional rootlets/charcoal (SM). Upper 6 inches: as above (SM). Vashon Lodgement TillLower 12 inches: moist, grayish brown, silty, fine to medium SAND, tracegravel; occasional rootlets; unsorted (SM). Drilling difficulty increases at 4.5 feet. Moist, brownish gray with slight oxidation, silty, fine to medium SAND,some gravel; broken gravel within sampler; unsorted (SM). As above; lack of slight oxidation (SM). As above; pounding on rock; blowcounts overstated. As above; contains sandier zones; ranges to very moist within sandierzones. 1 of 1 NAVD 88 CRC2" OD Split Spoon Sampler (SPT) 3" OD Split Spoon Sampler (D & M)Water LevelProject Name JHSWater Level ()Approved by: 30 Blows/Foot Samples~431 5 10 15 20 EB-18 Ring Sample No RecoveryGraphic 10 Other TestsHole Diameter (in) DESCRIPTION Driller/Equipment Blows/6"Exploration Boring Water Level at time of drilling (ATD) Renton School District Elementary School No. 16 M - Moisture Project Number 20 Renton, WA Date Start/Finish CompletionLocation Sheet Depth (ft)S T Exploration Number20180398E002 10/6/20,10/6/20 Logged by: Shelby Tube Sample 140# / 30"Advance Drill Tech / D50 Mobile Track Rig Well Ground Surface Elevation (ft) Grab SampleSymbol 8 inches 40 Datum Hammer Weight/Drop Sampler Type (ST):AESIBOR 20180398E002.GPJ November 18, 202099 4949 52 5050/5" 5050/5" 5050/5" 358 4410 31850/6" 172850/6" 3650/6" S-1 S-2 S-3 S-4 S-5 Bottom of exploration boring at 11 feetNo groundwater encountered. Topsoil - 2 inches FillLower 10 inches: moist, brown, silty, fine to medium SAND, some gravel;moderate rootlets/fine organic debris/charcoal; chaotic structure (SM). As above; poor recovery/brick debris (SM). Upper 6 inches: as above. Vashon Lodgement TillLower 12 inches: moist, grayish light brown with slight oxidation, silty, fineto medium SAND, some gravel; broken gravel within sampler; unsorted(SM). Moist, brownish gray, silty, fine to medium SAND, some gravel; brokengravel within sampler; unsorted (SM). As above. 1 of 1 NAVD 88 CRC2" OD Split Spoon Sampler (SPT) 3" OD Split Spoon Sampler (D & M)Water LevelProject Name JHSWater Level ()Approved by: 30 Blows/Foot Samples~430 5 10 15 20 EB-19 Ring Sample No RecoveryGraphic 10 Other TestsHole Diameter (in) DESCRIPTION Driller/Equipment Blows/6"Exploration Boring Water Level at time of drilling (ATD) Renton School District Elementary School No. 16 M - Moisture Project Number 20 Renton, WA Date Start/Finish CompletionLocation Sheet Depth (ft)S T Exploration Number20180398E002 10/6/20,10/6/20 Logged by: Shelby Tube Sample 140# / 30"Advance Drill Tech / D50 Mobile Track Rig Well Ground Surface Elevation (ft) Grab SampleSymbol 8 inches 40 Datum Hammer Weight/Drop Sampler Type (ST):AESIBOR 20180398E002.GPJ November 18, 20201313 1414 5050/6" 5050/6" 5050/6" 222 5119 81118 484150/6" 50/3" S-1 S-2 S-3 S-4 S-5 Bottom of exploration boring at 10.5 feetNo groundwater encountered. Topsoil - 2 inches FillLower 10 inches: moist, brown to dark brown with moderate oxidation, silty,fine to medium SAND; moderate roots, rootlets, and charcoal; chaoticstructure (SM). Vashon Lodgement Till Moist, grayish brown with moderate oxidation staining, silty, fine SAND;unsorted (SM). Increased drilling difficulty. Moist, grayish brown with slight oxidation, silty, fine to medium SAND,some gravel; unsorted (SM). Moist, brownish gray, silty, fine to medium SAND, some gravel; unsorted(SM). No recovery; bouncing on rock. 1 of 1 NAVD 88 CRC2" OD Split Spoon Sampler (SPT) 3" OD Split Spoon Sampler (D & M)Water LevelProject Name JHSWater Level ()Approved by: 30 Blows/Foot Samples~434 5 10 15 20 EB-20 Ring Sample No RecoveryGraphic 10 Other TestsHole Diameter (in) DESCRIPTION Driller/Equipment Blows/6"Exploration Boring Water Level at time of drilling (ATD) Renton School District Elementary School No. 16 M - Moisture Project Number 20 Renton, WA Date Start/Finish CompletionLocation Sheet Depth (ft)S T Exploration Number20180398E002 10/6/20,10/6/20 Logged by: Shelby Tube Sample 140# / 30"Advance Drill Tech / D50 Mobile Track Rig Well Ground Surface Elevation (ft) Grab SampleSymbol 8 inches 40 Datum Hammer Weight/Drop Sampler Type (ST):AESIBOR 20180398E002.GPJ November 18, 202044 2020 2929 5050/6" 5050/3" Particle Size Distribution Report PERCENT FINER0 10 20 30 40 50 60 70 80 90 100 GRAIN SIZE - mm. 0.0010.010.1110100 % +3"Coarse % Gravel Fine Coarse Medium % Sand Fine Silt % Fines Clay 0.0 7.5 9.1 4.1 16.3 23.7 39.36 in.3 in.2 in.1½ in.1 in.¾ in.½ in.3/8 in.#4#10#20#30#40#60#100#140#200TEST RESULTS Opening Percent Spec.*Pass? Size Finer (Percent)(X=Fail) Material Description Atterberg Limits (ASTM D 4318) Classification Coefficients Date Received:Date Tested: Tested By: Checked By: Title: Date Sampled:Location: Onsite Sample Number: EB-1 Depth: 5' Client: Project: Project No:Figure Very Silty Gravelly SAND 1.5 1 .75 .375 #4 #8 #10 #20 #40 #60 #100 #200 #270 100.0 92.5 92.5 88.1 83.4 80.2 79.3 73.8 63.0 48.8 42.5 39.3 38.5 np nv SM A-4(0) 12.7521 6.2954 0.3792 0.2641 8-24-18 8-24-18 BN BG 8-22-18 Greene Gasaway RSD Chelan Ave Properties 180398 E001 PL=LL=PI= USCS (D 2487)=AASHTO (M 145)= D90=D85=D60= D50=D30=D15= D10=Cu=Cc= Remarks *(no specification provided) Particle Size Distribution Report PERCENT FINER0 10 20 30 40 50 60 70 80 90 100 GRAIN SIZE - mm. 0.0010.010.1110100 % +3"Coarse % Gravel Fine Coarse Medium % Sand Fine Silt % Fines Clay 0.0 11.3 17.8 5.3 13.4 22.8 29.46 in.3 in.2 in.1½ in.1 in.¾ in.½ in.3/8 in.#4#10#20#30#40#60#100#140#200TEST RESULTS Opening Percent Spec.*Pass? Size Finer (Percent)(X=Fail) Material Description Atterberg Limits (ASTM D 4318) Classification Coefficients Date Received:Date Tested: Tested By: Checked By: Title: Date Sampled:Location: Onsite Sample Number: EB-7 Depth: 5' Client: Project: Project No:Figure Silty Gravelly SAND 1.5 1 .75 .375 #4 #8 #10 #20 #40 #60 #100 #200 #270 100.0 88.7 88.7 77.5 70.9 66.6 65.6 60.8 52.2 39.2 32.7 29.4 28.8 np nv SM A-2-4(0) 27.6933 13.8219 0.7604 0.3864 0.0931 8-24-18 8-24-18 BN BG 8-22-18 Greene Gasaway RSD Chelan Ave Properties 180398 E001 PL=LL=PI= USCS (D 2487)=AASHTO (M 145)= D90=D85=D60= D50=D30=D15= D10=Cu=Cc= Remarks *(no specification provided) November 26, 2019 Calvin Gasaway Greene Gasaway Architects, PLLC 31620 23rd Avenue South Federal Way, WA 98003-5049 Email: calvin@greenegasaway.com Phone: (206) 818-5466 Re: RSD Chelan Ave NE , Wetland Delineation Report The Watershed Company Reference Number: 180737 Dear Calvin: In September and October 2018, and July and September 2019, ecologists from The Watershed Company visited the Chelan Avenue NE study area in Renton, Washington, to delineate jurisdictional wetlands within a defined study area. This study is in support of the planning of new educational facilities for the Renton School District. This letter summarizes the findings of the study and details applicable federal, state, and local regulations. The following documents are enclosed: •Wetland Delineation Sketches (September 2018, July 2019, September 2019) •Site Map (surveyed by Terrane Land Surveying, Oct 2019)) •Wetland Determination Data Forms •Ecology Rating Forms and Figures Study Area In September and October 2018, King County parcels 102305-9173, -9249, -9138, -9124, - 9076, -9202, -9332, -9133, and -9139 were screened and delineated. Parcels -9096 and - 9275 were screened and delineated on July 16, 2019. Parcel -9107 was screened and delineated on September 27, 2019. EXHIBIT F Wetland Delineation Report RSD Chelan Avenue NE November 26, 2019 Page 2 Methods Public-domain information on the subject properties was reviewed for this delineation study and include the following: • USDA Natural Resources Conservation Service, Web Soil Survey (WSS) application • U.S. Fish and Wildlife Service National Wetland Inventory (NWI) maps • Washington Department of Fish and Wildlife interactive mapping programs (PHS on the Web, SalmonScape) • Washington Department of Natural Resources, Forest Practices Application Mapping Tool (FPARS) • Washington Department of Natural Resources, Wetlands of High Conservation Value Map Viewer • King County’s GIS mapping website (iMap) • City of Renton (COR) maps Characterization of climatic conditions for precipitation was determined using the WETS table methodology from the USDA NRCS document Part 650 Engineering Field Handbook, National Engineering Handbook, Hydrology Tools for Wetland Identification and Analysis, Chapter 19 (September 2015). The Seattle-Tacoma International AP station as recorded by NOAA from 1981-2010 (http://agacis.rcc- acis.org/) was used as a source for precipitation data. The WETS table methodology uses climate data from the three months prior to the site visit month to determine if normal conditions are present. Wetlands The study area was evaluated for wetlands using methodology from the Regional Supplement to the Corps of Engineers Wetland Delineation Manual: Western Mountains, Valleys, and Coast Region Version 2.0 (Regional Supplement) (US Army Corps of Engineers [Corps] May 2010). Wetland boundaries were determined on the basis of an examination of vegetation, soils, and hydrology. Areas meeting the criteria set forth in the Regional Supplement were determined to be wetland. Soil, vegetation, and hydrologic parameters were sampled at several locations along the wetland boundary to make the determination. Wetland Delineation Report RSD Chelan Avenue NE November 26, 2019 Page 3 Identified wetlands within the property boundaries were classified using the 2014 Update to the Western Washington Wetland Rating System (Publication #14-06-029) (Rating System). Streams The study area was evaluated for streams based on the presence or absence of an ordinary high water mark (OHWM) as defined by the Revised Code of Washington (RCW) 90.58.030 and the Washington Administrative Code (WAC) 220-660-030. Findings The approximately 12-acre study area is comprised of 12 residential properties zoned R- 8. The study area is located within the May Creek sub-basin of the Cedar – Sammamish Water Resource Inventory Area (WRIA 8); Township 23 North, Range 05 East, Section 10. The study area slopes gently to the northwest. A gravel-surfaced segment of Chelan Avenue NE lies in the center of the study area. Eleven single-family residences and multiple associated outbuildings are located on the properties. Public-domain information on the subject properties was reviewed for this study and include the following, as summarized in Table 1. Table 1. Summary of online mapping and inventory resources. Resource Summary USDA NRCS: Web Soil Survey Alderwood gravelly sandy loam, 8 to 15 percent slopes; Arents, Alderwood material, 6 to 15 percent slopes. USFWS: NWI Wetland Mapper No wetlands mapped within 500 feet of study area. WDFW: PHS on the Web No priority habitat or species mapped within 500 feet of study area. WDFW: SalmonScape No salmonids mapped within project site. Documented presence of salmonids in Honey Dew Creek, approx. 2,000 feet northwest of project area. Wetland Delineation Report RSD Chelan Avenue NE November 26, 2019 Page 4 WA-DNR: Forest Practices Activity Mapping Tool No mapped streams. Nearest streams approximately 2,000 feet northwest and east. King County iMap No streams or wetlands mapped within 500 feet of study area. City of Renton Maps Mapped wetland southeast of study area; across Duvall Ave NE. WETS Climatic Condition Drier than normal during all site visits except Sept 2019, which was wetter than normal. Wetlands Two wetlands were identified in the study area and are described in Table 2 and Table 3, below. An additional offsite wetland, identified on City of Renton GIS maps, is discussed further in the following section. Wetland Delineation Report RSD Chelan Avenue NE November 26, 2019 Page 5 Table 2. Wetland B assessment summary. WETLAND B – Assessment Summary Location: City of Renton; parcels 102305-9249, -9124, -9096 WRIA / Sub-basin: WRIA 8 / May Creek sub-basin 2014 Western WA Ecology Rating: Category IV Local Jurisdiction Buffer Width and Buffer Setback: 50-Foot Buffer 15-Foot Setback Wetland Size: Approx. 0.28 acres Cowardin Classifications: Palustrine Forested, Palustrine Scrub-shrub HGM Classifications: Depressional Wetland Data Sheets: DP-3, 8, 10 Upland Data Sheets: DP-7, 9, 11 Flag Color: Pink-and-black striped Flag Numbers: B-1 to B-23; BB-1 to BB-9 Vegetation Tree stratum: Black cottonwood, red alder, willow species Shrub stratum: Himalayan blackberry, cutleaf blackberry, hardhack Herb stratum: Slough sedge, lady fern, reed canarygrass, field bindweed Soils Soil survey: Alderwood gravelly sandy loam, 8 to 15 percent slopes Field data: Depleted matrix (F3) Hydrology Source: Groundwater, precipitation Field data: Water-stained leaves (B9), Geomorphic position (D2) Wetland Functions Improving Water Quality Hydrologic Habitat Site Potential H M L H M L H M L Landscape Potential H M L H M L H M L Value H M L H M L H M L TOTAL Score Based on Ratings 6 5 4 15 Description and Comments Wetland B is a shallow forested and scrub-shrub depressional wetland. The wetland is dominated by invasive species including Himalayan blackberry, reed canarygrass, and field bindweed. Hydrology is presumed to be provided by a seasonally high groundwater table and precipitation. No stormwater pipes or drainage ditches were observed to be contributing to the wetland unit. The wetland unit drains to the north, into a culvert observed at the southeast corner of parcel 1023059173. Slough sedge was observed in an area northeast of the wetland unit; DP-7 was recorded in this area. Wetland vegetation, soil, and hydrology indicators were not met in this area, and thus it was not included in the wetland unit. Wetland Delineation Report RSD Chelan Avenue NE November 26, 2019 Page 6 Table 3. Wetland C assessment summary. WETLAND C – Assessment Summary Location: City of Renton; parcels 102305-9275, -9107, -9138, -9076, -9133 WRIA / Sub-basin: WRIA 8 / May Creek sub-basin 2014 Western WA Ecology Rating: Category III Buffer Width: Buffer Setback: 100-Foot Buffer (75-ft recommended) 15-Foot Setback Wetland Size: Approx. 0.49 acre Cowardin Classifications: Palustrine Forested HGM Classifications: Depressional Wetland Data Sheets: DP-5, 14, 15 Upland Data Sheets: DP-6, 12, 13, 16 Flag Color: Pink-and-black striped Flag Numbers: C-1 to C-39; CC-1 to CC-15; CCC-1 to CCC-19 Vegetation Tree stratum: Black cottonwood, Oregon ash, western red cedar Shrub stratum: Salmonberry, hardhack, black twinberry, Himalayan blackberry, cutleaf blackberry Herb stratum: English ivy, slough sedge, soft rush, creeping buttercup Soils Soil survey: Alderwood gravelly sandy loam, 8 to 15 percent slopes Field data: Depleted matrix (F3), Redox Dark Surface (F6) Hydrology Source: Groundwater, precipitation, stormwater pond overflow Field data: Sparsely Vegetated Concave Surface (B8), Water-stained leaves (B9), Geomorphic position (D2), FAC-Neutral Test (D5) Wetland Functions Improving Water Quality Hydrologic Habitat Site Potential H M L H M L H M L Landscape Potential H M L H M L H M L Value H M L H M L H M L TOTAL Score Based on Ratings 7 7 5 19 Description and Comments Wetland C is a forested depressional wetland. Prevalent plant species include Oregon ash, black cottonwood, English ivy, slough sedge, and hardhack. Hydrology is provided by precipitation, hillslope runoff, and presumed overflow from a stormwater pond south of the wetland unit. A swale along the western boundary of parcel 102305-9133 appears to convey this flow into the wetland unit. DP-4 was recorded in this swale. Wetland soil and hydrology indicators were not met, and this area was thus not included in the wetland unit. An algal mat was present throughout much of the wetland area on parcel -9076. Culverts are present on parcel -9138 and -9275, which connect three lobes of the unit. The wetland is relatively flat and it is presumed that water is able to flow bi-directionally through these culverts. The wetland appears to drain to the north via a culvert observed at the northern boundary of parcel -9275. The outlet was dry at the time of the July and September site visits, but historic aerial photographs show the presence of an inundated swale connected to this outlet. Wetland Delineation Report RSD Chelan Avenue NE November 26, 2019 Page 7 Marginal Areas One marginal area was identified in a reconnaissance effort conducted by The Watershed Company in August 2018. This area was originally labeled “Wetland A.” Upon further inspection during the delineation phase, including the recording of Data Point 2, this area was determined to not meet wetland indicators. The area is described in the following table. Table 4. Marginal area (originally “Wetland A”) assessment summary. Marginal Area – Assessment Summary Location: City of Renton; parcels 1023059202, 1023059332 WRIA / Sub-basin: WRIA 8 / May Creek sub-basin 2014 Western WA Ecology Rating: NA Local Jurisdiction Buffer Width and Buffer Setback: NA Size: Approx. 1,000 sq. ft. Cowardin Classification(s): NA HGM Classification(s): NA Wetland Data Sheet(s): NA Upland Data Sheet (s): DP-2 Vegetation Tree stratum: None Shrub stratum: None Herb stratum: Poa sp., Creeping buttercup, common selfheal, white clover Soils Soil survey: Alderwood gravelly sandy loam, 8 to 15 percent slopes Field data: Redox Dark Surface (F6) Hydrology Source: Precipitation Field data: None Description and Comments This lawn area contained only facultative and facultative upland plants, exhibited very marginal hydric soils, and met no indicators of wetland hydrology. No hydrology sources were identified. Therefore, the area was determined to not be a wetland. Non-wetland areas Areas outside of identified wetlands did not meet criteria for hydrophytic vegetation, hydric soils, and wetland hydrology. These areas are dominated by Douglas-fir, bigleaf maple, Himalayan blackberry, English ivy, and maintained lawns. Wetland Delineation Report RSD Chelan Avenue NE November 26, 2019 Page 8 Streams The property lacked stream indicators including watermarks, stained leaves, algae, bed, bank, or hydraulically sorted sediments. Based on these findings, there are no jurisdictional streams on the property. Local Regulations Critical areas in the City of Renton are regulated by the City’s Critical Areas Regulations Renton Municipal Code (RMC) Title 4-3-050. According to the Code, wetlands are rated as one of four categories based on the Rating System. Wetland B received 6 points for water quality functions, 5 points for hydrologic functions, and 4 points for habitat functions, for a total of 15 points. This classifies Wetland B as a Category IV wetland. Wetland C received 7 points for water quality functions, 7 points for hydrologic functions, and 5 points for habitat functions, for a total of 19 points. This classifies Wetland C as a Category III wetland. Wetland buffers are established based on a combination of the wetland category, habitat score, and adjacent land use. A separate set of buffers is applied in areas of “low intensity” land use: unpaved trails, low intensity open space, or utility corridors. The current and proposed land use in the study area does not fall into that category. Wetland B, a Category IV wetland, will require a buffer of 50 feet. Wetland C, a Category III wetland with habitat scores of 5 points, requires a standard buffer of 100 feet, as measured from the wetland edges. Pursuant to RMC 4-3-050G. 9.d.iv, wetland buffers are to be increased beyond the standard required buffer width if certain unique circumstances are present. The criteria described in this code section are not applicable to the study area and therefore, increased buffers are not warranted. In addition, pursuant to RMC 4-3-050G.9.d.ii, alternate buffer widths may be proposed by a qualified wetland professional. A study shall demonstrate why the standard buffer widths are unnecessary and how alternative widths will provide equivalent ecological protection. The study shall also demonstrate how alternative buffers meet best available science standards. In this instance, we recommend the City of Renton consider the Wetland C habitat score of 5 to be a “low” score and the standard buffer should therefore be 75 feet. In previous Ecology wetland buffer guidance, “low” habitat function was represented by a score of 3 or 4 points. However, after a detailed analysis of habitat scores for the 211 reference Wetland Delineation Report RSD Chelan Avenue NE November 26, 2019 Page 9 wetlands used to calibrate the rating system, Ecology found that wetlands scoring 3, 4, or 5 points for habitat are more similarly distributed to those scoring ≤ 19 points in the 2004 version. This information prompted Ecology to adjust the habitat score break points in the current wetland buffer tables in July 2018. The modified tables now group habitat scores of 3 to 5 into “low” habitat function. Wetland buffers in the City of Renton require an additional 15-foot critical area setback. Table 5. Summary of wetland rating scores, classification, and standard buffer widths per RMC 4-30-050(G)(2). Water Quality Hydrologic Habitat Total Category/Type Standard Buffer Width Wetland B 6 5 4 15 IV 50 ft. Wetland C 7 7 5 19 III 100 ft. (75-feet recommended) The City of Renton allows certain activities in wetlands and their associated buffers as exemptions. These include habitat conservation, preservation, habitat enhancement, restoration/mitigation, site investigative work, surface water discharge, maintenance of existing facilities, utilities within the public right-of-way, temporary wetland impacts if restored, maintenance or replacement of existing structures or improvements, modification of an existing single family dwelling, and the continuance of existing activities. The wetland identified on the City of Renton GIS maps is across Duvall Avenue NE from the study area. Per RMC 4-3-050G.2.6, “Areas that are functionally and effectively disconnected from the wetland by a permanent road or other substantially developed surface of sufficient width and with use characteristics such that buffer functions are not provided shall not be counted toward the minimum buffer unless these areas can be feasibly removed, relocated or restored to provide buffer functions.” Duvall Avenue NE is a four-lane thoroughfare in an urban area and interrupts all functions provided by the standard buffer. Thus, the study area is effectively disconnected from the wetland and does not provide buffer functions. It is highly unlikely that it would ever be removed, Wetland Delineation Report RSD Chelan Avenue NE November 26, 2019 Page 10 relocated, or restored to provide buffer functions. Thus, the buffers applied to the wetland would not encumber the study area. Figure 1. COR GIS map with wetland identified across Duvall Avenue NE from study area. Wetland buffers may be altered if it can be documented that the modified buffer will provide greater function than the standard buffer. This can be completed through buffer averaging or enhancement of the existing buffer (RMC 4-3-050I.3). Averaging allows for reducing the buffer in some areas while increasing the buffer in other areas and may require enhancement in areas that are reduced. Buffers can also be reduced by providing enhancement of the existing buffer. This generally includes removal of invasive species and planting of desirable native species. Wetland buffers may be reduced or averaged by up to 25% of the standard width, or a minimum width of 75 feet in the instance of Wetlands B and C. Reduction or averaging of wetland buffers by more than 25% can only be authorized by a variance. Approval of a variance requires compliance with the decision criteria of RMC 4-9-250.B.5, including a demonstration that the applicant would suffer an unnecessary hardship because of special circumstances applicable to the property and that the variance request is the minimum necessary to accomplish the project purpose. Any request for buffer averaging or buffer reduction is to be made as part of a project critical areas study. COR-mapped wetland Study area (only southern portion shown) Wetland Delineation Report RSD Chelan Avenue NE November 26, 2019 Page 11 Direct wetland impacts, in addition to being subject to state and federal regulations outlined below, are permitted by the City only if an applicant can prove that the development proposal results in no net loss of wetland acreage and/or function (RMC 4- 3-050J.4). Proposals are subject to mitigation sequencing; an applicant must prove that no alternative exists that is less intrusive to the critical area. The City prefers compensation take place on-site, through re-establishment of former wetlands, rehabilitation of wetlands to restore natural functions, creation of wetlands on disturbed upland sites, or enhancing significantly degraded wetlands. If on-site mitigation is not feasible, “cooperative compensation to mitigation banks or in-lieu fee programs” are allowed. Unlike buffer reductions that exceed 25%, direct wetland impacts do not require a variance. The City strongly encourages pre-application consultation for all prospective projects involving critical areas. Such early coordination can result in a better understanding of permit processes, submittal requirements, and approval timelines. State and Federal Regulations Wetlands and streams are regulated by the Corps under Section 404 of the Clean Water Act. Any proposed filling or other direct impacts to Waters of the U.S., including wetlands (except isolated wetlands), would require notification and permits from the Corps. Unavoidable impacts are typically required to be compensated through implementation of an approved mitigation plan. Federally permitted actions that could affect endangered species may also require a biological assessment study and consultation with the U.S. Fish and Wildlife Service and/or the National Marine Fisheries Service. Compliance with the Endangered Species Act must be demonstrated for activities within jurisdictional wetlands and the 100-year floodplain. Application for Corps permits may also require an individual 401 Water Quality Certification and Coastal Zone Management Consistency determination from Ecology and a cultural resource study in accordance with Section 106 of the National Historic Preservation Act. Washington Department of Ecology Similar to the Corps, Ecology, under Section 401 of the Clean Water Act, is charged with reviewing, conditioning, and approving or denying certain federally permitted actions that result in discharges to state waters. However, Ecology review would only become Wetland Delineation Report RSD Chelan Avenue NE November 26, 2019 Page 12 necessary if a Section 404 permit from the Corps was issued or if the Corps did not take jurisdiction over the wetlands. Therefore, if filling activities are avoided, authorization from Ecology would not be needed. If filling is proposed, a JARPA could be submitted to Ecology in order to obtain a Section 401 Water Quality Certification (WQC) and Coastal Zone Management Consistency Determination. Ecology permits are either issued concurrently with the Corps permit or within 90 days following the Corps permit. In general, neither the Corps nor Ecology regulates wetland buffers, unless direct impacts are proposed. When direct impacts are proposed, mitigated wetlands may be required to employ buffers based on Corps and Ecology joint regulatory guidance. Disclaimer The information contained in this letter or report is based on the application of technical guidelines currently accepted as the best available science and in conjunction with the manuals and criteria outlined in the methods section. All discussions, conclusions and recommendations reflect the best professional judgment of the author(s) and are based upon information available at the time the study was conducted. All work was completed within the constraints of budget, scope, and timing. The findings of this report are subject to verification and agreement by the appropriate local, state and federal regulatory authorities. No other warranty, expressed or implied, is made. Please call if you have any questions or if we can provide you with any additional information. Sincerely, Logan Dougherty Ecologist Hugh Mortensen, PWS President/Senior Ecologist Page 1 of 1 Delineation Sketch – RSD Chelan Avenue Parcel Numbers: 1023059107, 1023059249, 1023059138, Prepared for: Calvin Gasaway Site Visit Date: 1023059124, 1023059076, 1023059202, 1023059133, 1023059332, 1023059139 September 20-21, 2018 Jurisdiction: Renton, WA Note: Field sketch only. Features depicted are approximate and not to scale. Wetland boundary is marked with pink- and black-striped flags. Data points are marked with yellow- and black-striped flags. LEGEND Wetland Delineated Wetland Boundary Non-delineated Wetland Boundary Study Area Culvert Data Point (DP) Wetland B Flags B-1 to B-23 Wetland C Flags C-1 to C-39 Connect C-1 to C-39 Do Not Connect C-18 to C-19 Do Not Connect C-26 to C-27 Do Not Connect C-22 to C-23 DP-1 DP-2 DP-3 DP-4 DP-5 DP-6 DP-7 DP-8 DP-9   This page intentionally left blank. Page 1 of 1 Delineation Sketch – RSD Chelan Avenue (Lots 3 and 4) Parcel Numbers: 1023059096, 1023059275 Prepared for: Calvin Gasaway Site Visit Date: July 16, 2019 TWC Ref. No.: 180737 DP-12 Note: Field sketch only. Features depicted are approximate and not to scale. Wetland boundary is marked with pink- and black-striped flags. Data points are marked with yellow- and black-striped flags. Wetland C, CC Line Flags CC-1 to CC-15 DP-13 DP-14 DP-11 Do not connect CC-3 to CC-4; Do not connect CC-11 to CC-12 DP-10 Wetland B, BB Line Flags BB-1 to BB-9 Connect BB-1 to B-1 Connect BB-9 to B-23 LEGEND Wetland Delineated Wetland Boundary Non-delineated Wetland Boundary Previously-delineated Wetland Boundary Study Area Culvert Data Point (DP) 371371376376EXISTING FEATURESPROPERTY BOUNDARYDELINEATED WETLAND BOUNDARYWETLAND BUFFER (110-FT)STREAM OHWMPROPOSED FEATURESSTRUCTURE FOOTPRINT (885 SF)DRIVEWAY FOOTPRINT (405 SF)PERMANENT BUFFER IMPACTS (TOTALDEVELOPMENT AREA) (2,955 SF)TEMPORARY BUFFER IMPACTS (760 SF)SILT FENCE (180 FT)PROJECT MANAGER: DESIGNED: DRAFTED: CHECKED:SHEET SIZE:ORIGINAL PLAN IS 22" x 34".SCALE ACCORDINGLY.BY© Copyright- The Watershed CompanyDATEPRINTED BYFILENAMES c i e n c e & D e s i g n750 Sixth Street SouthKirkland WA 98033p 425.822.5242www.watershedco.comJOB NUMBER:SHEET NUMBER:SUBMITTALS & REVISIONSDESCRIPTIONDATENO.GRAHAM PROPERTYMITIGATION PLANPREPARED FOR: DENNIS GRAHAMPARCEL #00375000002500140TH ST SWUNINCORPORATED SNOHOMISH COUNTY, WA SP--RHCM / SP171210OF 31 02-22-2018 DELINEATION MAPLM2 09-12-2018 MITIGATION PLANRHIMPACTS ASSESSMENTW240105020SCALE: 1" = 10'STREAM A OHWM(150-FT BUFFER)WETLAND ABOUNDARYLEGENDDITCHROWPROPOSEDSINGLE FAMILYRESIDENCEPROPOSED SILTFENCEPROPOSEDDRIVEWAYScale: NTSSILT FENCEA110-FTWETLANDBUFFER8' MAX.LAKE / RIVER / WETLANDSECTIONELEVATIONSILT FENCE MAINTENANCE STANDARDS:1. ANY DAMAGE SHALL BE REPAIRED IMMEDIATELY.2. SEDIMENT SHALL BE REMOVED WHEN ACCUMULATION EXCEEDS 6" IN DEPTH.SILT FENCE FABRIC AND WIRE MESH BACKINGSHALL BE WIRED TO TOP, MIDDLE ANDBOTTOM OF POSTKEY SILT FENCE BOTTOM IN 4" X 4" MINIMUMTRENCH BACKFILLED WITH NATIVE MATERIAL.TRENCH THE ENTIRE LENGTH OF THE FENCEWITH NO BREAKS.SILT CONTAINMENT FENCE JOINTSIN FILTER FABRIC SHALL BESPLICED AT POSTS. USESTAPLES,WIRE RINGS, OREQUIVALENT TO ATTACH FABRIC TOPOSTS.CUT-AWAYSHOWING 2"X2", 14GAUGE WIRE MESHBACKINGSTEEL "T" POST OR 2"x4" WOOD POSTS, OREQUIVALENTFINISH GRADEEDGE OFROAD11042'26'15'5'3' MIN.10'12'140TH ST SWPROPOSED SPLITRAIL FENCEThis page intentionally left blank. Page 1 of 1 Delineation Sketch – RSD Chelan Avenue (Lot 5) Parcel Numbers: 1023059107 Prepared for: Calvin Gasaway Site Visit Date: September 27, 2019 TWC Ref. No.: 180737 Note: Field sketch only. Features depicted are approximate and not to scale. Wetland boundary is marked with pink- and black-striped flags. Data points are marked with yellow- and black-striped flags. Wetland C, CCC Line Flags CCC-1 to CCC-19 DP-16 LEGEND Wetland Delineated Wetland Boundary Previously-delineated Wetland Boundary Study Area Culvert Data Point (DP) DP-15 Connect CCC-1 to CC-1 Connect CCC-19 to CC-15 Connect CCC-11 to C-23 Connect CCC-10 to C-22 Wetland C, C Line Previously Delineated Wetland C, CC Line Previously Delineated 371371376376EXISTING FEATURESPROPERTY BOUNDARYDELINEATED WETLAND BOUNDARYWETLAND BUFFER (110-FT)STREAM OHWMPROPOSED FEATURESSTRUCTURE FOOTPRINT (885 SF)DRIVEWAY FOOTPRINT (405 SF)PERMANENT BUFFER IMPACTS (TOTALDEVELOPMENT AREA) (2,955 SF)TEMPORARY BUFFER IMPACTS (760 SF)SILT FENCE (180 FT)PROJECT MANAGER: DESIGNED: DRAFTED: CHECKED:SHEET SIZE:ORIGINAL PLAN IS 22" x 34".SCALE ACCORDINGLY.BY© Copyright- The Watershed CompanyDATEPRINTED BYFILENAMES c i e n c e & D e s i g n750 Sixth Street SouthKirkland WA 98033p 425.822.5242www.watershedco.comJOB NUMBER:SHEET NUMBER:SUBMITTALS & REVISIONSDESCRIPTIONDATENO.GRAHAM PROPERTYMITIGATION PLANPREPARED FOR: DENNIS GRAHAMPARCEL #00375000002500140TH ST SWUNINCORPORATED SNOHOMISH COUNTY, WA SP--RHCM / SP171210OF 31 02-22-2018 DELINEATION MAPLM2 09-12-2018 MITIGATION PLANRHIMPACTS ASSESSMENTW240105020SCALE: 1" = 10'STREAM A OHWM(150-FT BUFFER)WETLAND ABOUNDARYLEGENDDITCHROWPROPOSEDSINGLE FAMILYRESIDENCEPROPOSED SILTFENCEPROPOSEDDRIVEWAYScale: NTSSILT FENCEA110-FTWETLANDBUFFER8' MAX.LAKE / RIVER / WETLANDSECTIONELEVATIONSILT FENCE MAINTENANCE STANDARDS:1. ANY DAMAGE SHALL BE REPAIRED IMMEDIATELY.2. SEDIMENT SHALL BE REMOVED WHEN ACCUMULATION EXCEEDS 6" IN DEPTH.SILT FENCE FABRIC AND WIRE MESH BACKINGSHALL BE WIRED TO TOP, MIDDLE ANDBOTTOM OF POSTKEY SILT FENCE BOTTOM IN 4" X 4" MINIMUMTRENCH BACKFILLED WITH NATIVE MATERIAL.TRENCH THE ENTIRE LENGTH OF THE FENCEWITH NO BREAKS.SILT CONTAINMENT FENCE JOINTSIN FILTER FABRIC SHALL BESPLICED AT POSTS. USESTAPLES,WIRE RINGS, OREQUIVALENT TO ATTACH FABRIC TOPOSTS.CUT-AWAYSHOWING 2"X2", 14GAUGE WIRE MESHBACKINGSTEEL "T" POST OR 2"x4" WOOD POSTS, OREQUIVALENTFINISH GRADEEDGE OFROAD11042'26'15'5'3' MIN.10'12'140TH ST SWPROPOSED SPLITRAIL FENCEThis page intentionally left blank. SURVEYOR'S CERTIFICATEBASIS OF BEARINGSREFERENCESLEGENDVICINITY MAPN.T.S.ALTA/NSPS LAND TITLE SURVEY ALTA/NSPS LAND TITLE SURVEYRENTON SCHOOL DISTRICTVERTICAL DATUMN.T.S.CONTROL MAP ALTA/NSPS LAND TITLE SURVEY ALTA/NSPS LAND TITLE SURVEYRENTON SCHOOL DISTRICT LEGEND ALTA/NSPS LAND TITLE SURVEY ALTA/NSPS LAND TITLE SURVEYRENTON SCHOOL DISTRICT LEGEND ALTA/NSPS LAND TITLE SURVEY ALTA/NSPS LAND TITLE SURVEYRENTON SCHOOL DISTRICT LEGEND ALTA/NSPS LAND TITLE SURVEY ALTA/NSPS LAND TITLE SURVEYRENTON SCHOOL DISTRICT LEGEND ALTA/NSPS LAND TITLE SURVEY ALTA/NSPS LAND TITLE SURVEYRENTON SCHOOL DISTRICT LEGEND ALTA/NSPS LAND TITLE SURVEY ALTA/NSPS LAND TITLE SURVEYRENTON SCHOOL DISTRICT LEGEND ALTA/NSPS LAND TITLE SURVEY ALTA/NSPS LAND TITLE SURVEYRENTON SCHOOL DISTRICT LEGEND ALTA/NSPS LAND TITLE SURVEY ALTA/NSPS LAND TITLE SURVEYRENTON SCHOOL DISTRICT LEGEND ALTA/NSPS LAND TITLE SURVEY ALTA/NSPS LAND TITLE SURVEYRENTON SCHOOL DISTRICT LOT 2 LEGAL DESCRIPTIONLOT 2 PROPERTY ADDRESSLOT 2 SURVEYOR'S NOTESLOT 2 SCHEDULE B ITEMSLOT 3 LEGAL DESCRIPTIONLOT 3 PROPERTY ADDRESSLOT 3 SURVEYOR'S NOTESLOT 3 SCHEDULE B ITEMSLOT 4 LEGAL DESCRIPTIONLOT 4 PROPERTY ADDRESSLOT 4 SURVEYOR'S NOTESLOT 4 SCHEDULE B ITEMSLOT 5 LEGAL DESCRIPTIONLOT 5 PROPERTY ADDRESSLOT 5 SURVEYOR'S NOTESLOT 5 SCHEDULE B ITEMSLOT 6 LEGAL DESCRIPTIONLOT 6 PROPERTY ADDRESSLOT 5 SURVEYOR'S NOTES CONTINUEDLOT 6 SURVEYOR'S NOTESLOT 6 SURVEYOR'S NOTES CONTINUEDLOT 6 SCHEDULE B ITEMSLOT 7 & 10 LEGAL DESCRIPTIONLOT 7 & 10 PROPERTY ADDRESSLOT 7 & 10 SURVEYOR'S NOTES ALTA/NSPS LAND TITLE SURVEY ALTA/NSPS LAND TITLE SURVEYRENTON SCHOOL DISTRICT LOT 7 & 10 SCHEDULE B ITEMSLOT 9 LEGAL DESCRIPTIONLOT 9 PROPERTY ADDRESSLOT 9 SURVEYOR'S NOTESLOT 9 SCHEDULE B ITEMSLOT 11 & 12 LEGAL DESCRIPTIONLOT 11 & 12 PROPERTY ADDRESSLOT 11 & 12 SCHEDULE B ITEMSLOT 7 & 10 SURVEYOR'S NOTES CONTINUEDLOT 9 SURVEYOR'S NOTES CONTINUEDLOT 11 & 12 SURVEYOR'S NOTESLOT 11 & 12 SURVEYOR'S NOTES CONTINUEDLOT 14 LEGAL DESCRIPTIONLOT 14 PROPERTY ADDRESSLOT 14 SURVEYOR'S NOTESLOT 14 SURVEYOR'S NOTES CONTINUEDLOT 14 SCHEDULE B ITEMS US Army Corps of Engineers Western Mountains, Valleys, and Coast – Version 2.0 DP-1 Project/Site: Chelan Ave NE, Renton, WA City/County: Renton, WA Sampling date: 8/21/18 Applicant/Owner: Calvin Gasaway State: WA Sampling Point: 1 Investigator(s): R. Kahlo, C. McIngalls Section, Township, Range: 10, 23N, 05E Landform (hillslope, terrace, etc): Hillslope Local relief (concave, convex, none): None Slope (%): <2% Subregion (LRR): A Lat: Long: Datum: Soil Map Unit Name: Alderwood gravelly sandy loam, 8 to 15 percent slopes NWI classification: None Are climatic / hydrologic conditions on the site typical for this time of year? ☐ Yes ☒ No (If no, explain in remarks.) Are Vegetation ☐, Soil ☐, or Hydrology ☐ significantly disturbed? Are “Normal Circumstances” present on the site? ☒ Yes ☐ No Are Vegetation ☐, Soil ☐, or Hydrology ☐ naturally problematic? (If needed, explain any answers in Remarks.) SUMMARY OF FINDINGS – Attach site map showing sampling point locations, transects, important features, etc. Hydrophytic Vegetation Present? Yes ☐ No ☒ Is the Sampled Area within a Wetland? Yes ☐ No ☒ Hydric Soils Present? Yes ☐ No ☒ Wetland Hydrology Present? Yes ☐ No ☒ Remarks: SE corner of study area. Climatic conditions considered “drier than normal” per WETS table methodology. VEGETATION – Use scientific names of plants. Tree Stratum (Plot size: 5-m diameter) Absolute % Cover Dominant Species? Indicator Status Dominance Test worksheet: Number of Dominant Species that are OBL, FACW, or FAC: 1 (A) 1. 2. Total Number of Dominant Species Across all Strata: 3 (B) 3. 4. Percent of Dominant Species that are OBL, FACW, or FAC: 33 (A/B) 0 = Total Cover Sapling/Shrub Stratum (Plot size: 3-m diameter) Prevalence Index worksheet: 1. Spiraea douglasii 80 Y FACW Total % Cover of: Multiply by: 2. Rubus laciniatus 40 Y FACU OBL species x 1 = 3. FACW species x 2 = 4. FAC species x 3 = 5. FACU species x 4 = 120 = Total Cover UPL species x 5 = Herb Stratum (Plot size: 1-m diameter) Column Totals: (A) (B) 1. Rubus ursinus 60 Y FACU Prevalence Index = B/A = 2. 3. Hydrophytic Vegetation Indicators: 4. ☐ 1 – Rapid Test for Hydrophytic Vegetation 5. ☐ 2 – Dominance Test is > 50% 6. ☐ 3 – Prevalence Index is ≤ 3.01 7. ☐ 4 – Morphological Adaptations1 (Provide supporting data in Remarks or on a separate sheet) 8. 9. ☐ 5 – Wetland Non-Vascular Plants1 10. ☐ Problematic Hydrophytic Vegetation1 (Explain) 11. 1Indicators of hydric soil and wetland hydrology must be present, unless disturbed or problematic. 60 = Total Cover Woody Vine Stratum (Plot size: 3-m diameter) Hydrophytic Vegetation Present? Yes ☐ No ☒ 1. 2. 0 = Total Cover % Bare Ground in Herb Stratum: 40 Remarks: WETLAND DETERMINATION DATA FORM – Western Mountains, Valleys, and Coast Region US Army Corps of Engineers Western Mountains, Valleys, and Coast – Version 2.0 SOIL Sampling Point: DP-1 HYDROLOGY Profile Description: (Describe to the depth needed to document the indicator or confirm the absence of indicators.) Depth Matrix Redox Features (inches) Color (moist) % Color (moist) % Type1 Loc2 Texture Remarks 0-3 2.5Y 3/3 100 Sandy loam 3-12 10YR 3/4 100 Sandy loam 1Type: C=Concentration, D=Depletion, RM=Reduced Matrix, CS=Covered or Coated Sand Grains. 2Loc: PL=Pore Lining, M=Matrix. Hydric Soil Indicators: (Applicable to all LRRs, unless otherwise noted.) Indicators for Problematic Hydric Soils3: ☐ Histosol (A1) ☐ Sandy Redox (S5) ☐ 2cm Muck (A10) ☐ Histic Epipedon (A2) ☐ Stripped Matrix (S6) ☐ Red Parent Material (TF2) ☐ Black Histic (A3) ☐ Loamy Mucky Mineral (F1) (except MLRA 1) ☐ Very Shallow Dark Surface (TF12) ☐ Hydrogen Sulfide (A4) ☐ Loamy Gleyed Matrix (F2) ☐ Other (Explain in Remarks) ☐ Depleted Below Dark Surface (A11) ☐ Depleted Matrix (F3) ☐ Thick Dark Surface (A12) ☐ Redox Dark Surface (F6) 3 Indicators of hydrophytic vegetation and wetland hydrology must be present, unless disturbed or problematic. ☐ Sandy Mucky Mineral (S1) ☐ Depleted Dark Surface (F7) ☐ Sandy Gleyed Matrix (S4) ☐ Redox Depressions (F8) Restrictive Layer (if present): Hydric soil present? Yes ☐ No ☒ Type: Depth (inches): Remarks: Wetland Hydrology Indicators: Primary Indicators (minimum of one required: check all that apply) Secondary Indicators (2 or more required) ☐ Surface water (A1) ☐ Water-Stained Leaves (except MLRA 1, 2, 4A & 4B) (B9) ☐ Water-Stained Leaves (B9) (MLRA 1, 2, 4A & 4B) ☐ High Water Table (A2) ☐ Saturation (A3) ☐ Salt Crust (B11) ☐ Drainage Patterns (B10) ☐ Water Marks (B1) ☐ Aquatic Invertebrates (B13) ☐ Dry-Season Water Table (C2) ☐ Sediment Deposits (B2) ☐ Hydrogen Sulfide Odor (C1) ☐ Saturation Visible on Aerial Imagery (C9) ☐ Drift Deposits (B3) ☐ Oxidized Rhizospheres along Living Roots (C3) ☐ Geomorphic Position (D2) ☐ Algal Mat or Crust (B4) ☐ Presence of Reduced Iron (C4) ☐ Shallow Aquitard (D3) ☐ Iron Deposits (B5) ☐ Recent Iron Reduction in Tilled Soils (C6) ☐ FAC-Neutral Test (D5) ☐ Surface Soil Cracks (B6) ☐ Stunted or Stressed Plants (D1) (LRR A) ☐ Raised Ant Mounds (D6) (LRR A) ☐ Inundation Visible on Aerial Imagery (B7) ☐ Other (explain in remarks) ☐ Frost-Heave Hummocks ☐ Sparsely Vegetated Concave Surface (B8) Field Observations: Wetland Hydrology Present? Yes ☐ No ☒ Surface Water Present? Yes ☐ No ☒ Depth (in): Water Table Present? Yes ☐ No ☒ Depth (in): Saturation Present? Yes ☐ No ☒ Depth (in): (includes capillary fringe) Describe Recorded Data (stream gauge, monitoring well, aerial photos, previous inspections), if available: Remarks: Completely dry. US Army Corps of Engineers Western Mountains, Valleys, and Coast – Version 2.0 DP-2 Project/Site: Chelan Ave NE, Renton, WA City/County: Renton, WA Sampling date: 9/20/18 Applicant/Owner: Calvin Gasaway State: WA Sampling Point: 2 Investigator(s): L. Dougherty, P. Heltzel Section, Township, Range: 10, 23N, 05E Landform (hillslope, terrace, etc): Hillslope Local relief (concave, convex, none): None Slope (%): <2% Subregion (LRR): A Lat: Long: Datum: Soil Map Unit Name: Alderwood gravelly sandy loam, 8 to 15 percent slopes NWI classification: None Are climatic / hydrologic conditions on the site typical for this time of year? ☐ Yes ☒ No (If no, explain in remarks.) Are Vegetation ☐, Soil ☐, or Hydrology ☐ significantly disturbed? Are “Normal Circumstances” present on the site? ☒ Yes ☐ No Are Vegetation ☐, Soil ☐, or Hydrology ☐ naturally problematic? (If needed, explain any answers in Remarks.) SUMMARY OF FINDINGS – Attach site map showing sampling point locations, transects, important features, etc. Hydrophytic Vegetation Present? Yes ☒ No ☐ Is the Sampled Area within a Wetland? Yes ☐ No ☒ Hydric Soils Present? Yes ☒ No ☐ Wetland Hydrology Present? Yes ☐ No ☒ Remarks: Backyard of 1070 Chelan Ave NE: open grassy area. Climatic conditions considered “drier than normal” per WETS table methodology. VEGETATION – Use scientific names of plants. Tree Stratum (Plot size: 5-m diameter) Absolute % Cover Dominant Species? Indicator Status Dominance Test worksheet: Number of Dominant Species that are OBL, FACW, or FAC: 2 (A) 1. 2. Total Number of Dominant Species Across all Strata: 2 (B) 3. 4. Percent of Dominant Species that are OBL, FACW, or FAC: 100 (A/B) 0 = Total Cover Sapling/Shrub Stratum (Plot size: 3-m diameter) Prevalence Index worksheet: 1. Total % Cover of: Multiply by: 2. OBL species x 1 = 3. FACW species x 2 = 4. FAC species x 3 = 5. FACU species x 4 = 0 = Total Cover UPL species x 5 = Herb Stratum (Plot size: 1-m diameter) Column Totals: (A) (B) 1. Ranunculus repens 50 Y FAC Prevalence Index = B/A = 2. Trifolium repens 50 Y FAC 3. Poa sp. 20 N FAC* Hydrophytic Vegetation Indicators: 4. Prunella vulgaris 10 N FACU ☐ 1 – Rapid Test for Hydrophytic Vegetation 5. ☒ 2 – Dominance Test is > 50% 6. ☐ 3 – Prevalence Index is ≤ 3.01 7. ☐ 4 – Morphological Adaptations1 (Provide supporting data in Remarks or on a separate sheet) 8. 9. ☐ 5 – Wetland Non-Vascular Plants1 10. ☐ Problematic Hydrophytic Vegetation1 (Explain) 11. 1Indicators of hydric soil and wetland hydrology must be present, unless disturbed or problematic. 130 = Total Cover Woody Vine Stratum (Plot size: 3-m diameter) Hydrophytic Vegetation Present? Yes ☒ No ☐ 1. 2. 0 = Total Cover % Bare Ground in Herb Stratum: Remarks: *Presumed FAC indicator status. WETLAND DETERMINATION DATA FORM – Western Mountains, Valleys, and Coast Region US Army Corps of Engineers Western Mountains, Valleys, and Coast – Version 2.0 SOIL Sampling Point: DP-2 HYDROLOGY Profile Description: (Describe to the depth needed to document the indicator or confirm the absence of indicators.) Depth Matrix Redox Features (inches) Color (moist) % Color (moist) % Type1 Loc2 Texture Remarks 0-10 10YR 3/2 95 7.5YR 4/4 5 C M, PL Gravelly sandy loam 10-14 10YR 3/3 95 7.5YR 4/4 5 C M, PL Gravelly sandy loam 1Type: C=Concentration, D=Depletion, RM=Reduced Matrix, CS=Covered or Coated Sand Grains. 2Loc: PL=Pore Lining, M=Matrix. Hydric Soil Indicators: (Applicable to all LRRs, unless otherwise noted.) Indicators for Problematic Hydric Soils3: ☐ Histosol (A1) ☐ Sandy Redox (S5) ☐ 2cm Muck (A10) ☐ Histic Epipedon (A2) ☐ Stripped Matrix (S6) ☐ Red Parent Material (TF2) ☐ Black Histic (A3) ☐ Loamy Mucky Mineral (F1) (except MLRA 1) ☐ Very Shallow Dark Surface (TF12) ☐ Hydrogen Sulfide (A4) ☐ Loamy Gleyed Matrix (F2) ☐ Other (Explain in Remarks) ☐ Depleted Below Dark Surface (A11) ☐ Depleted Matrix (F3) ☐ Thick Dark Surface (A12) ☒ Redox Dark Surface (F6) 3 Indicators of hydrophytic vegetation and wetland hydrology must be present, unless disturbed or problematic. ☐ Sandy Mucky Mineral (S1) ☐ Depleted Dark Surface (F7) ☐ Sandy Gleyed Matrix (S4) ☐ Redox Depressions (F8) Restrictive Layer (if present): Hydric soil present? Yes ☒ No ☐ Type: Depth (inches): Remarks: Wetland Hydrology Indicators: Primary Indicators (minimum of one required: check all that apply) Secondary Indicators (2 or more required) ☐ Surface water (A1) ☐ Water-Stained Leaves (except MLRA 1, 2, 4A & 4B) (B9) ☐ Water-Stained Leaves (B9) (MLRA 1, 2, 4A & 4B) ☐ High Water Table (A2) ☐ Saturation (A3) ☐ Salt Crust (B11) ☐ Drainage Patterns (B10) ☐ Water Marks (B1) ☐ Aquatic Invertebrates (B13) ☐ Dry-Season Water Table (C2) ☐ Sediment Deposits (B2) ☐ Hydrogen Sulfide Odor (C1) ☐ Saturation Visible on Aerial Imagery (C9) ☐ Drift Deposits (B3) ☐ Oxidized Rhizospheres along Living Roots (C3) ☐ Geomorphic Position (D2) ☐ Algal Mat or Crust (B4) ☐ Presence of Reduced Iron (C4) ☐ Shallow Aquitard (D3) ☐ Iron Deposits (B5) ☐ Recent Iron Reduction in Tilled Soils (C6) ☐ FAC-Neutral Test (D5) ☐ Surface Soil Cracks (B6) ☐ Stunted or Stressed Plants (D1) (LRR A) ☐ Raised Ant Mounds (D6) (LRR A) ☐ Inundation Visible on Aerial Imagery (B7) ☐ Other (explain in remarks) ☐ Frost-Heave Hummocks ☐ Sparsely Vegetated Concave Surface (B8) Field Observations: Wetland Hydrology Present? Yes ☐ No ☒ Surface Water Present? Yes ☐ No ☒ Depth (in): Water Table Present? Yes ☐ No ☒ Depth (in): Saturation Present? Yes ☐ No ☒ Depth (in): (includes capillary fringe) Describe Recorded Data (stream gauge, monitoring well, aerial photos, previous inspections), if available: Remarks: Completely dry. US Army Corps of Engineers Western Mountains, Valleys, and Coast – Version 2.0 DP-3 Project/Site: Chelan Ave NE, Renton, WA City/County: Renton, WA Sampling date: 8/21/18 Applicant/Owner: Calvin Gasaway State: WA Sampling Point: 3 Investigator(s): R. Kahlo, C. McIngalls Section, Township, Range: 10, 23N, 05E Landform (hillslope, terrace, etc): Depression Local relief (concave, convex, none): None Slope (%): 0 Subregion (LRR): A Lat: Long: Datum: Soil Map Unit Name: Alderwood gravelly sandy loam, 8 to 15 percent slopes NWI classification: None Are climatic / hydrologic conditions on the site typical for this time of year? ☐ Yes ☒ No (If no, explain in remarks.) Are Vegetation ☐, Soil ☐, or Hydrology ☐ significantly disturbed? Are “Normal Circumstances” present on the site? ☒ Yes ☐ No Are Vegetation ☐, Soil ☐, or Hydrology ☐ naturally problematic? (If needed, explain any answers in Remarks.) SUMMARY OF FINDINGS – Attach site map showing sampling point locations, transects, important features, etc. Hydrophytic Vegetation Present? Yes ☒ No ☐ Is the Sampled Area within a Wetland? Yes ☒ No ☐ Hydric Soils Present? Yes ☒ No ☐ Wetland Hydrology Present? Yes ☒ No ☐ Remarks: Wetland B in-pit. Climatic conditions considered “drier than normal” per WETS table methodology. VEGETATION – Use scientific names of plants. Tree Stratum (Plot size: 5-m diameter) Absolute % Cover Dominant Species? Indicator Status Dominance Test worksheet: Number of Dominant Species that are OBL, FACW, or FAC: 3 (A) 1. 2. Total Number of Dominant Species Across all Strata: 4 (B) 3. 4. Percent of Dominant Species that are OBL, FACW, or FAC: 75 (A/B) 0 = Total Cover Sapling/Shrub Stratum (Plot size: 3-m diameter) Prevalence Index worksheet: 1. Salix lucida 20 Y FACW Total % Cover of: Multiply by: 2. Rubus armeniacus 20 Y FAC OBL species x 1 = 3. FACW species x 2 = 4. FAC species x 3 = 5. FACU species x 4 = 20 = Total Cover UPL species x 5 = Herb Stratum (Plot size: 1-m diameter) Column Totals: (A) (B) 1. Phalaris arundinacea 40 Y FACW Prevalence Index = B/A = 2. Ranunculus repens 20 N FAC 3. Convolvulus arvensis 50 Y UPL Hydrophytic Vegetation Indicators: 4. ☐ 1 – Rapid Test for Hydrophytic Vegetation 5. ☒ 2 – Dominance Test is > 50% 6. ☐ 3 – Prevalence Index is ≤ 3.01 7. ☐ 4 – Morphological Adaptations1 (Provide supporting data in Remarks or on a separate sheet) 8. 9. ☐ 5 – Wetland Non-Vascular Plants1 10. ☐ Problematic Hydrophytic Vegetation1 (Explain) 11. 1Indicators of hydric soil and wetland hydrology must be present, unless disturbed or problematic. 110 = Total Cover Woody Vine Stratum (Plot size: 3-m diameter) Hydrophytic Vegetation Present? Yes ☒ No ☐ 1. 2. 0 = Total Cover % Bare Ground in Herb Stratum: 0 Remarks: WETLAND DETERMINATION DATA FORM – Western Mountains, Valleys, and Coast Region US Army Corps of Engineers Western Mountains, Valleys, and Coast – Version 2.0 SOIL Sampling Point: DP-3 HYDROLOGY Profile Description: (Describe to the depth needed to document the indicator or confirm the absence of indicators.) Depth Matrix Redox Features (inches) Color (moist) % Color (moist) % Type1 Loc2 Texture Remarks 0-14 10YR 2/1 100 Sandy loam 14-20 2.5Y 4/2 80 7.5YR 3/4 20 C M Sandy loam 1Type: C=Concentration, D=Depletion, RM=Reduced Matrix, CS=Covered or Coated Sand Grains. 2Loc: PL=Pore Lining, M=Matrix. Hydric Soil Indicators: (Applicable to all LRRs, unless otherwise noted.) Indicators for Problematic Hydric Soils3: ☐ Histosol (A1) ☐ Sandy Redox (S5) ☐ 2cm Muck (A10) ☐ Histic Epipedon (A2) ☐ Stripped Matrix (S6) ☐ Red Parent Material (TF2) ☐ Black Histic (A3) ☐ Loamy Mucky Mineral (F1) (except MLRA 1) ☐ Very Shallow Dark Surface (TF12) ☐ Hydrogen Sulfide (A4) ☐ Loamy Gleyed Matrix (F2) ☐ Other (Explain in Remarks) ☐ Depleted Below Dark Surface (A11) ☐ Depleted Matrix (F3) ☒ Thick Dark Surface (A12) ☐ Redox Dark Surface (F6) 3 Indicators of hydrophytic vegetation and wetland hydrology must be present, unless disturbed or problematic. ☐ Sandy Mucky Mineral (S1) ☐ Depleted Dark Surface (F7) ☐ Sandy Gleyed Matrix (S4) ☐ Redox Depressions (F8) Restrictive Layer (if present): Hydric soil present? Yes ☒ No ☐ Type: Depth (inches): Remarks: Wetland Hydrology Indicators: Primary Indicators (minimum of one required: check all that apply) Secondary Indicators (2 or more required) ☐ Surface water (A1) ☐ Water-Stained Leaves (except MLRA 1, 2, 4A & 4B) (B9) ☐ Water-Stained Leaves (B9) (MLRA 1, 2, 4A & 4B) ☐ High Water Table (A2) ☐ Saturation (A3) ☐ Salt Crust (B11) ☐ Drainage Patterns (B10) ☐ Water Marks (B1) ☐ Aquatic Invertebrates (B13) ☐ Dry-Season Water Table (C2) ☐ Sediment Deposits (B2) ☐ Hydrogen Sulfide Odor (C1) ☐ Saturation Visible on Aerial Imagery (C9) ☐ Drift Deposits (B3) ☒ Oxidized Rhizospheres along Living Roots (C3) ☒ Geomorphic Position (D2) ☐ Algal Mat or Crust (B4) ☐ Presence of Reduced Iron (C4) ☐ Shallow Aquitard (D3) ☐ Iron Deposits (B5) ☐ Recent Iron Reduction in Tilled Soils (C6) ☒ FAC-Neutral Test (D5) ☐ Surface Soil Cracks (B6) ☐ Stunted or Stressed Plants (D1) (LRR A) ☐ Raised Ant Mounds (D6) (LRR A) ☐ Inundation Visible on Aerial Imagery (B7) ☐ Other (explain in remarks) ☐ Frost-Heave Hummocks ☐ Sparsely Vegetated Concave Surface (B8) Field Observations: Wetland Hydrology Present? Yes ☒ No ☐ Surface Water Present? Yes ☐ No ☒ Depth (in): Water Table Present? Yes ☐ No ☒ Depth (in): Saturation Present? Yes ☐ No ☒ Depth (in): (includes capillary fringe) Describe Recorded Data (stream gauge, monitoring well, aerial photos, previous inspections), if available: Remarks: Damp, but not saturated. US Army Corps of Engineers Western Mountains, Valleys, and Coast – Version 2.0 DP-4 Project/Site: Chelan Ave NE, Renton, WA City/County: Renton, WA Sampling date: 9/20/18 Applicant/Owner: Calvin Gasaway State: WA Sampling Point: 4 Investigator(s): L. Dougherty, P. Heltzel Section, Township, Range: 10, 23N, 05E Landform (hillslope, terrace, etc): Depression / swale Local relief (concave, convex, none): None Slope (%): <2% Subregion (LRR): A Lat: Long: Datum: Soil Map Unit Name: Alderwood gravelly sandy loam, 8 to 15 percent slopes NWI classification: None Are climatic / hydrologic conditions on the site typical for this time of year? ☐ Yes ☒ No (If no, explain in remarks.) Are Vegetation ☐, Soil ☐, or Hydrology ☐ significantly disturbed? Are “Normal Circumstances” present on the site? ☒ Yes ☐ No Are Vegetation ☐, Soil ☐, or Hydrology ☐ naturally problematic? (If needed, explain any answers in Remarks.) SUMMARY OF FINDINGS – Attach site map showing sampling point locations, transects, important features, etc. Hydrophytic Vegetation Present? Yes ☒ No ☐ Is the Sampled Area within a Wetland? Yes ☐ No ☒ Hydric Soils Present? Yes ☐ No ☒ Wetland Hydrology Present? Yes ☐ No ☒ Remarks: Swale in backyard of 1051 Chelan Ave NE. Climatic conditions considered “drier than normal” per WETS table methodology. VEGETATION – Use scientific names of plants. Tree Stratum (Plot size: 5-m diameter) Absolute % Cover Dominant Species? Indicator Status Dominance Test worksheet: Number of Dominant Species that are OBL, FACW, or FAC: 3 (A) 1. Fraxinus latifolia 80 Y FACW 2. Populus balsamifera 40 Y FAC Total Number of Dominant Species Across all Strata: 4 (B) 3. 4. Percent of Dominant Species that are OBL, FACW, or FAC: 75 (A/B) 120 = Total Cover Sapling/Shrub Stratum (Plot size: 3-m diameter) Prevalence Index worksheet: 1. Rosa sp. 30 Y FAC* Total % Cover of: Multiply by: 2. OBL species x 1 = 3. FACW species x 2 = 4. FAC species x 3 = 5. FACU species x 4 = 30 = Total Cover UPL species x 5 = Herb Stratum (Plot size: 1-m diameter) Column Totals: (A) (B) 1. Hedera helix 40 Y FACU Prevalence Index = B/A = 2. 3. Hydrophytic Vegetation Indicators: 4. ☐ 1 – Rapid Test for Hydrophytic Vegetation 5. ☒ 2 – Dominance Test is > 50% 6. ☐ 3 – Prevalence Index is ≤ 3.01 7. ☐ 4 – Morphological Adaptations1 (Provide supporting data in Remarks or on a separate sheet) 8. 9. ☐ 5 – Wetland Non-Vascular Plants1 10. ☐ Problematic Hydrophytic Vegetation1 (Explain) 11. 1Indicators of hydric soil and wetland hydrology must be present, unless disturbed or problematic. 40 = Total Cover Woody Vine Stratum (Plot size: 3-m diameter) Hydrophytic Vegetation Present? Yes ☒ No ☐ 1. 2. 0 = Total Cover % Bare Ground in Herb Stratum: 60 Remarks: *Presumed FAC indicator status. WETLAND DETERMINATION DATA FORM – Western Mountains, Valleys, and Coast Region US Army Corps of Engineers Western Mountains, Valleys, and Coast – Version 2.0 SOIL Sampling Point: DP-4 HYDROLOGY Profile Description: (Describe to the depth needed to document the indicator or confirm the absence of indicators.) Depth Matrix Redox Features (inches) Color (moist) % Color (moist) % Type1 Loc2 Texture Remarks 0-14 10YR 2/1 100 Gravelly sandy silt 1Type: C=Concentration, D=Depletion, RM=Reduced Matrix, CS=Covered or Coated Sand Grains. 2Loc: PL=Pore Lining, M=Matrix. Hydric Soil Indicators: (Applicable to all LRRs, unless otherwise noted.) Indicators for Problematic Hydric Soils3: ☐ Histosol (A1) ☐ Sandy Redox (S5) ☐ 2cm Muck (A10) ☐ Histic Epipedon (A2) ☐ Stripped Matrix (S6) ☐ Red Parent Material (TF2) ☐ Black Histic (A3) ☐ Loamy Mucky Mineral (F1) (except MLRA 1) ☐ Very Shallow Dark Surface (TF12) ☐ Hydrogen Sulfide (A4) ☐ Loamy Gleyed Matrix (F2) ☐ Other (Explain in Remarks) ☐ Depleted Below Dark Surface (A11) ☐ Depleted Matrix (F3) ☐ Thick Dark Surface (A12) ☐ Redox Dark Surface (F6) 3 Indicators of hydrophytic vegetation and wetland hydrology must be present, unless disturbed or problematic. ☐ Sandy Mucky Mineral (S1) ☐ Depleted Dark Surface (F7) ☐ Sandy Gleyed Matrix (S4) ☐ Redox Depressions (F8) Restrictive Layer (if present): Hydric soil present? Yes ☐ No ☒ Type: Depth (inches): Remarks: Wetland Hydrology Indicators: Primary Indicators (minimum of one required: check all that apply) Secondary Indicators (2 or more required) ☐ Surface water (A1) ☐ Water-Stained Leaves (except MLRA 1, 2, 4A & 4B) (B9) ☐ Water-Stained Leaves (B9) (MLRA 1, 2, 4A & 4B) ☐ High Water Table (A2) ☐ Saturation (A3) ☐ Salt Crust (B11) ☐ Drainage Patterns (B10) ☐ Water Marks (B1) ☐ Aquatic Invertebrates (B13) ☐ Dry-Season Water Table (C2) ☐ Sediment Deposits (B2) ☐ Hydrogen Sulfide Odor (C1) ☐ Saturation Visible on Aerial Imagery (C9) ☐ Drift Deposits (B3) ☐ Oxidized Rhizospheres along Living Roots (C3) ☒ Geomorphic Position (D2) ☐ Algal Mat or Crust (B4) ☐ Presence of Reduced Iron (C4) ☐ Shallow Aquitard (D3) ☐ Iron Deposits (B5) ☐ Recent Iron Reduction in Tilled Soils (C6) ☐ FAC-Neutral Test (D5) ☐ Surface Soil Cracks (B6) ☐ Stunted or Stressed Plants (D1) (LRR A) ☐ Raised Ant Mounds (D6) (LRR A) ☐ Inundation Visible on Aerial Imagery (B7) ☐ Other (explain in remarks) ☐ Frost-Heave Hummocks ☐ Sparsely Vegetated Concave Surface (B8) Field Observations: Wetland Hydrology Present? Yes ☐ No ☒ Surface Water Present? Yes ☐ No ☒ Depth (in): Water Table Present? Yes ☐ No ☒ Depth (in): Saturation Present? Yes ☐ No ☒ Depth (in): (includes capillary fringe) Describe Recorded Data (stream gauge, monitoring well, aerial photos, previous inspections), if available: Remarks: Completely dry. US Army Corps of Engineers Western Mountains, Valleys, and Coast – Version 2.0 DP-5 Project/Site: Chelan Ave NE, Renton, WA City/County: Renton, WA Sampling date: 9/20/18 Applicant/Owner: Calvin Gasaway State: WA Sampling Point: 5 Investigator(s): L. Dougherty, P. Heltzel Section, Township, Range: 10, 23N, 05E Landform (hillslope, terrace, etc): Depression Local relief (concave, convex, none): Concave Slope (%): 0 Subregion (LRR): A Lat: Long: Datum: Soil Map Unit Name: Alderwood gravelly sandy loam, 8 to 15 percent slopes NWI classification: None Are climatic / hydrologic conditions on the site typical for this time of year? ☐ Yes ☒ No (If no, explain in remarks.) Are Vegetation ☐, Soil ☐, or Hydrology ☐ significantly disturbed? Are “Normal Circumstances” present on the site? ☒ Yes ☐ No Are Vegetation ☐, Soil ☐, or Hydrology ☐ naturally problematic? (If needed, explain any answers in Remarks.) SUMMARY OF FINDINGS – Attach site map showing sampling point locations, transects, important features, etc. Hydrophytic Vegetation Present? Yes ☒ No ☐ Is the Sampled Area within a Wetland? Yes ☒ No ☐ Hydric Soils Present? Yes ☒ No ☐ Wetland Hydrology Present? Yes ☒ No ☐ Remarks: Wetland C in-pit. Climatic conditions considered “drier than normal” per WETS table methodology. VEGETATION – Use scientific names of plants. Tree Stratum (Plot size: 5-m diameter) Absolute % Cover Dominant Species? Indicator Status Dominance Test worksheet: Number of Dominant Species that are OBL, FACW, or FAC: 3 (A) 1. Fraxinus latifolia 100 Y FACW 2. Populus balsamifera 30 Y FAC Total Number of Dominant Species Across all Strata: 3 (B) 3. 4. Percent of Dominant Species that are OBL, FACW, or FAC: 100 (A/B) 130 = Total Cover Sapling/Shrub Stratum (Plot size: 3-m diameter) Prevalence Index worksheet: 1. Total % Cover of: Multiply by: 2. OBL species x 1 = 3. FACW species x 2 = 4. FAC species x 3 = 5. FACU species x 4 = 0 = Total Cover UPL species x 5 = Herb Stratum (Plot size: 1-m diameter) Column Totals: (A) (B) 1. Carex obnupta 40 Y OBL Prevalence Index = B/A = 2. Hedera helix Trace N FACU 3. Hydrophytic Vegetation Indicators: 4. ☐ 1 – Rapid Test for Hydrophytic Vegetation 5. ☒ 2 – Dominance Test is > 50% 6. ☐ 3 – Prevalence Index is ≤ 3.01 7. ☐ 4 – Morphological Adaptations1 (Provide supporting data in Remarks or on a separate sheet) 8. 9. ☐ 5 – Wetland Non-Vascular Plants1 10. ☐ Problematic Hydrophytic Vegetation1 (Explain) 11. 1Indicators of hydric soil and wetland hydrology must be present, unless disturbed or problematic. 40 = Total Cover Woody Vine Stratum (Plot size: 3-m diameter) Hydrophytic Vegetation Present? Yes ☒ No ☐ 1. 2. 0 = Total Cover % Bare Ground in Herb Stratum: Remarks: WETLAND DETERMINATION DATA FORM – Western Mountains, Valleys, and Coast Region US Army Corps of Engineers Western Mountains, Valleys, and Coast – Version 2.0 SOIL Sampling Point: DP-5 HYDROLOGY Profile Description: (Describe to the depth needed to document the indicator or confirm the absence of indicators.) Depth Matrix Redox Features (inches) Color (moist) % Color (moist) % Type1 Loc2 Texture Remarks 0-9 10YR 2/1 100 Gravelly sandy silt 9-15 5Y 5/2 95 7.5YR 5/6 5 C M Gravelly sandy loam 1Type: C=Concentration, D=Depletion, RM=Reduced Matrix, CS=Covered or Coated Sand Grains. 2Loc: PL=Pore Lining, M=Matrix. Hydric Soil Indicators: (Applicable to all LRRs, unless otherwise noted.) Indicators for Problematic Hydric Soils3: ☐ Histosol (A1) ☐ Sandy Redox (S5) ☐ 2cm Muck (A10) ☐ Histic Epipedon (A2) ☐ Stripped Matrix (S6) ☐ Red Parent Material (TF2) ☐ Black Histic (A3) ☐ Loamy Mucky Mineral (F1) (except MLRA 1) ☐ Very Shallow Dark Surface (TF12) ☐ Hydrogen Sulfide (A4) ☐ Loamy Gleyed Matrix (F2) ☐ Other (Explain in Remarks) ☐ Depleted Below Dark Surface (A11) ☒ Depleted Matrix (F3) ☐ Thick Dark Surface (A12) ☐ Redox Dark Surface (F6) 3 Indicators of hydrophytic vegetation and wetland hydrology must be present, unless disturbed or problematic. ☐ Sandy Mucky Mineral (S1) ☐ Depleted Dark Surface (F7) ☐ Sandy Gleyed Matrix (S4) ☐ Redox Depressions (F8) Restrictive Layer (if present): Hydric soil present? Yes ☒ No ☐ Type: Depth (inches): Remarks: Wetland Hydrology Indicators: Primary Indicators (minimum of one required: check all that apply) Secondary Indicators (2 or more required) ☐ Surface water (A1) ☐ Water-Stained Leaves (except MLRA 1, 2, 4A & 4B) (B9) ☒ Water-Stained Leaves (B9) (MLRA 1, 2, 4A & 4B) ☐ High Water Table (A2) ☐ Saturation (A3) ☐ Salt Crust (B11) ☐ Drainage Patterns (B10) ☐ Water Marks (B1) ☐ Aquatic Invertebrates (B13) ☐ Dry-Season Water Table (C2) ☐ Sediment Deposits (B2) ☐ Hydrogen Sulfide Odor (C1) ☐ Saturation Visible on Aerial Imagery (C9) ☐ Drift Deposits (B3) ☐ Oxidized Rhizospheres along Living Roots (C3) ☒ Geomorphic Position (D2) ☐ Algal Mat or Crust (B4) ☐ Presence of Reduced Iron (C4) ☐ Shallow Aquitard (D3) ☐ Iron Deposits (B5) ☐ Recent Iron Reduction in Tilled Soils (C6) ☐ FAC-Neutral Test (D5) ☐ Surface Soil Cracks (B6) ☐ Stunted or Stressed Plants (D1) (LRR A) ☐ Raised Ant Mounds (D6) (LRR A) ☐ Inundation Visible on Aerial Imagery (B7) ☐ Other (explain in remarks) ☐ Frost-Heave Hummocks ☒ Sparsely Vegetated Concave Surface (B8) Field Observations: Wetland Hydrology Present? Yes ☒ No ☐ Surface Water Present? Yes ☐ No ☒ Depth (in): Water Table Present? Yes ☐ No ☒ Depth (in): Saturation Present? Yes ☐ No ☒ Depth (in): (includes capillary fringe) Describe Recorded Data (stream gauge, monitoring well, aerial photos, previous inspections), if available: Remarks: Patches of algal mat present throughout wetland. US Army Corps of Engineers Western Mountains, Valleys, and Coast – Version 2.0 DP-6 Project/Site: Chelan Ave NE, Renton, WA City/County: Renton, WA Sampling date: 9/20/18 Applicant/Owner: Calvin Gasaway State: WA Sampling Point: 6 Investigator(s): L. Dougherty, P. Heltzel Section, Township, Range: 10, 23N, 05E Landform (hillslope, terrace, etc): Hillslope Local relief (concave, convex, none): None Slope (%): 5% Subregion (LRR): A Lat: Long: Datum: Soil Map Unit Name: Alderwood gravelly sandy loam, 8 to 15 percent slopes NWI classification: None Are climatic / hydrologic conditions on the site typical for this time of year? ☐ Yes ☒ No (If no, explain in remarks.) Are Vegetation ☐, Soil ☐, or Hydrology ☐ significantly disturbed? Are “Normal Circumstances” present on the site? ☒ Yes ☐ No Are Vegetation ☐, Soil ☐, or Hydrology ☐ naturally problematic? (If needed, explain any answers in Remarks.) SUMMARY OF FINDINGS – Attach site map showing sampling point locations, transects, important features, etc. Hydrophytic Vegetation Present? Yes ☒ No ☐ Is the Sampled Area within a Wetland? Yes ☐ No ☒ Hydric Soils Present? Yes ☐ No ☒ Wetland Hydrology Present? Yes ☐ No ☒ Remarks: Wetland C out-pit. Climatic conditions considered “drier than normal” per WETS table methodology. VEGETATION – Use scientific names of plants. Tree Stratum (Plot size: 5-m diameter) Absolute % Cover Dominant Species? Indicator Status Dominance Test worksheet: Number of Dominant Species that are OBL, FACW, or FAC: 4 (A) 1. Fraxinus latifolia 60 Y FACW 2. Populus balsamifera 10 N FAC Total Number of Dominant Species Across all Strata: 5 (B) 3. 4. Percent of Dominant Species that are OBL, FACW, or FAC: 80 (A/B) 70 = Total Cover Sapling/Shrub Stratum (Plot size: 3-m diameter) Prevalence Index worksheet: 1. Rubus armeniacus 50 Y FAC Total % Cover of: Multiply by: 2. Malus fusca 15 Y FACW OBL species x 1 = 3. FACW species x 2 = 4. FAC species x 3 = 5. FACU species x 4 = 65 = Total Cover UPL species x 5 = Herb Stratum (Plot size: 1-m diameter) Column Totals: (A) (B) 1. Rubus ursinus 10 Y FACU Prevalence Index = B/A = 2. Ranunculus repens 5 Y FAC 3. Hydrophytic Vegetation Indicators: 4. ☐ 1 – Rapid Test for Hydrophytic Vegetation 5. ☒ 2 – Dominance Test is > 50% 6. ☐ 3 – Prevalence Index is ≤ 3.01 7. ☐ 4 – Morphological Adaptations1 (Provide supporting data in Remarks or on a separate sheet) 8. 9. ☐ 5 – Wetland Non-Vascular Plants1 10. ☐ Problematic Hydrophytic Vegetation1 (Explain) 11. 1Indicators of hydric soil and wetland hydrology must be present, unless disturbed or problematic. 15 = Total Cover Woody Vine Stratum (Plot size: 3-m diameter) Hydrophytic Vegetation Present? Yes ☒ No ☐ 1. 2. 0 = Total Cover % Bare Ground in Herb Stratum: 85 Remarks: WETLAND DETERMINATION DATA FORM – Western Mountains, Valleys, and Coast Region US Army Corps of Engineers Western Mountains, Valleys, and Coast – Version 2.0 SOIL Sampling Point: DP-6 HYDROLOGY Profile Description: (Describe to the depth needed to document the indicator or confirm the absence of indicators.) Depth Matrix Redox Features (inches) Color (moist) % Color (moist) % Type1 Loc2 Texture Remarks 0-3 10YR 2/1 100 Silty loam 3-12* 10YR 3/2 99 7.5YR 5/6 1 C M Gravelly sandy loam 1Type: C=Concentration, D=Depletion, RM=Reduced Matrix, CS=Covered or Coated Sand Grains. 2Loc: PL=Pore Lining, M=Matrix. Hydric Soil Indicators: (Applicable to all LRRs, unless otherwise noted.) Indicators for Problematic Hydric Soils3: ☐ Histosol (A1) ☐ Sandy Redox (S5) ☐ 2cm Muck (A10) ☐ Histic Epipedon (A2) ☐ Stripped Matrix (S6) ☐ Red Parent Material (TF2) ☐ Black Histic (A3) ☐ Loamy Mucky Mineral (F1) (except MLRA 1) ☐ Very Shallow Dark Surface (TF12) ☐ Hydrogen Sulfide (A4) ☐ Loamy Gleyed Matrix (F2) ☐ Other (Explain in Remarks) ☐ Depleted Below Dark Surface (A11) ☐ Depleted Matrix (F3) ☐ Thick Dark Surface (A12) ☐ Redox Dark Surface (F6) 3 Indicators of hydrophytic vegetation and wetland hydrology must be present, unless disturbed or problematic. ☐ Sandy Mucky Mineral (S1) ☐ Depleted Dark Surface (F7) ☐ Sandy Gleyed Matrix (S4) ☐ Redox Depressions (F8) Restrictive Layer (if present): Hydric soil present? Yes ☐ No ☒ Type: Depth (inches): Remarks: *Couldn’t dig past 12” due to compaction. Wetland Hydrology Indicators: Primary Indicators (minimum of one required: check all that apply) Secondary Indicators (2 or more required) ☐ Surface water (A1) ☐ Water-Stained Leaves (except MLRA 1, 2, 4A & 4B) (B9) ☐ Water-Stained Leaves (B9) (MLRA 1, 2, 4A & 4B) ☐ High Water Table (A2) ☐ Saturation (A3) ☐ Salt Crust (B11) ☐ Drainage Patterns (B10) ☐ Water Marks (B1) ☐ Aquatic Invertebrates (B13) ☐ Dry-Season Water Table (C2) ☐ Sediment Deposits (B2) ☐ Hydrogen Sulfide Odor (C1) ☐ Saturation Visible on Aerial Imagery (C9) ☐ Drift Deposits (B3) ☐ Oxidized Rhizospheres along Living Roots (C3) ☐ Geomorphic Position (D2) ☐ Algal Mat or Crust (B4) ☐ Presence of Reduced Iron (C4) ☐ Shallow Aquitard (D3) ☐ Iron Deposits (B5) ☐ Recent Iron Reduction in Tilled Soils (C6) ☐ FAC-Neutral Test (D5) ☐ Surface Soil Cracks (B6) ☐ Stunted or Stressed Plants (D1) (LRR A) ☐ Raised Ant Mounds (D6) (LRR A) ☐ Inundation Visible on Aerial Imagery (B7) ☐ Other (explain in remarks) ☐ Frost-Heave Hummocks ☐ Sparsely Vegetated Concave Surface (B8) Field Observations: Wetland Hydrology Present? Yes ☐ No ☒ Surface Water Present? Yes ☐ No ☒ Depth (in): Water Table Present? Yes ☐ No ☒ Depth (in): Saturation Present? Yes ☐ No ☒ Depth (in): (includes capillary fringe) Describe Recorded Data (stream gauge, monitoring well, aerial photos, previous inspections), if available: Remarks: Completely dry. US Army Corps of Engineers Western Mountains, Valleys, and Coast – Version 2.0 DP-7 Project/Site: Chelan Ave NE, Renton, WA City/County: Renton, WA Sampling date: 9/21/18 Applicant/Owner: Calvin Gasaway State: WA Sampling Point: 7 Investigator(s): L. Dougherty, P. Heltzel Section, Township, Range: 10, 23N, 05E Landform (hillslope, terrace, etc): Hillslope Local relief (concave, convex, none): None Slope (%): <2% Subregion (LRR): A Lat: Long: Datum: Soil Map Unit Name: Alderwood gravelly sandy loam, 8 to 15 percent slopes NWI classification: None Are climatic / hydrologic conditions on the site typical for this time of year? ☐ Yes ☒ No (If no, explain in remarks.) Are Vegetation ☐, Soil ☐, or Hydrology ☐ significantly disturbed? Are “Normal Circumstances” present on the site? ☒ Yes ☐ No Are Vegetation ☐, Soil ☐, or Hydrology ☐ naturally problematic? (If needed, explain any answers in Remarks.) SUMMARY OF FINDINGS – Attach site map showing sampling point locations, transects, important features, etc. Hydrophytic Vegetation Present? Yes ☐ No ☒ Is the Sampled Area within a Wetland? Yes ☐ No ☒ Hydric Soils Present? Yes ☐ No ☒ Wetland Hydrology Present? Yes ☐ No ☒ Remarks: Wetland B out-pit; NE of wetland unit. Climatic conditions considered “drier than normal” per WETS table methodology. VEGETATION – Use scientific names of plants. Tree Stratum (Plot size: 5-m diameter) Absolute % Cover Dominant Species? Indicator Status Dominance Test worksheet: Number of Dominant Species that are OBL, FACW, or FAC: 3 (A) 1. Pseudotsuga menziesii 60 Y FACU 2. Alnus rubra 50 Y FAC Total Number of Dominant Species Across all Strata: 8 (B) 3. 4. Percent of Dominant Species that are OBL, FACW, or FAC: 37.5 (A/B) 110 = Total Cover Sapling/Shrub Stratum (Plot size: 3-m diameter) Prevalence Index worksheet: 1. Rubus armeniacus 30 Y FAC Total % Cover of: Multiply by: 2. Ilex aquifolium 20 Y FACU OBL species x 1 = 3. Rubus laciniatus 15 Y FACU FACW species x 2 = 4. Sorbus aucuparia 5 N UPL FAC species x 3 = 5. Spiraea douglasii 2 N FACW FACU species x 4 = 72 = Total Cover UPL species x 5 = Herb Stratum (Plot size: 1-m diameter) Column Totals: (A) (B) 1. Carex obnupta 60 Y OBL Prevalence Index = B/A = 2. Hedera helix 60 Y FACU 3. Rubus ursinus 30 Y FACU Hydrophytic Vegetation Indicators: 4. ☐ 1 – Rapid Test for Hydrophytic Vegetation 5. ☐ 2 – Dominance Test is > 50% 6. ☐ 3 – Prevalence Index is ≤ 3.01 7. ☐ 4 – Morphological Adaptations1 (Provide supporting data in Remarks or on a separate sheet) 8. 9. ☐ 5 – Wetland Non-Vascular Plants1 10. ☐ Problematic Hydrophytic Vegetation1 (Explain) 11. 1Indicators of hydric soil and wetland hydrology must be present, unless disturbed or problematic. 150 = Total Cover Woody Vine Stratum (Plot size: 3-m diameter) Hydrophytic Vegetation Present? Yes ☐ No ☒ 1. 2. 0 = Total Cover % Bare Ground in Herb Stratum: 0 Remarks: WETLAND DETERMINATION DATA FORM – Western Mountains, Valleys, and Coast Region US Army Corps of Engineers Western Mountains, Valleys, and Coast – Version 2.0 SOIL Sampling Point: DP-7 HYDROLOGY Profile Description: (Describe to the depth needed to document the indicator or confirm the absence of indicators.) Depth Matrix Redox Features (inches) Color (moist) % Color (moist) % Type1 Loc2 Texture Remarks 0-8 10YR 2/1 100 Gravelly sandy loam 8-16 10YR 4/6 97 7.5YR 5/6 3 C M Gravelly sandy loam 1Type: C=Concentration, D=Depletion, RM=Reduced Matrix, CS=Covered or Coated Sand Grains. 2Loc: PL=Pore Lining, M=Matrix. Hydric Soil Indicators: (Applicable to all LRRs, unless otherwise noted.) Indicators for Problematic Hydric Soils3: ☐ Histosol (A1) ☐ Sandy Redox (S5) ☐ 2cm Muck (A10) ☐ Histic Epipedon (A2) ☐ Stripped Matrix (S6) ☐ Red Parent Material (TF2) ☐ Black Histic (A3) ☐ Loamy Mucky Mineral (F1) (except MLRA 1) ☐ Very Shallow Dark Surface (TF12) ☐ Hydrogen Sulfide (A4) ☐ Loamy Gleyed Matrix (F2) ☐ Other (Explain in Remarks) ☐ Depleted Below Dark Surface (A11) ☐ Depleted Matrix (F3) ☐ Thick Dark Surface (A12) ☐ Redox Dark Surface (F6) 3 Indicators of hydrophytic vegetation and wetland hydrology must be present, unless disturbed or problematic. ☐ Sandy Mucky Mineral (S1) ☐ Depleted Dark Surface (F7) ☐ Sandy Gleyed Matrix (S4) ☐ Redox Depressions (F8) Restrictive Layer (if present): Hydric soil present? Yes ☐ No ☒ Type: Depth (inches): Remarks: Wetland Hydrology Indicators: Primary Indicators (minimum of one required: check all that apply) Secondary Indicators (2 or more required) ☐ Surface water (A1) ☐ Water-Stained Leaves (except MLRA 1, 2, 4A & 4B) (B9) ☐ Water-Stained Leaves (B9) (MLRA 1, 2, 4A & 4B) ☐ High Water Table (A2) ☐ Saturation (A3) ☐ Salt Crust (B11) ☐ Drainage Patterns (B10) ☐ Water Marks (B1) ☐ Aquatic Invertebrates (B13) ☐ Dry-Season Water Table (C2) ☐ Sediment Deposits (B2) ☐ Hydrogen Sulfide Odor (C1) ☐ Saturation Visible on Aerial Imagery (C9) ☐ Drift Deposits (B3) ☐ Oxidized Rhizospheres along Living Roots (C3) ☐ Geomorphic Position (D2) ☐ Algal Mat or Crust (B4) ☐ Presence of Reduced Iron (C4) ☐ Shallow Aquitard (D3) ☐ Iron Deposits (B5) ☐ Recent Iron Reduction in Tilled Soils (C6) ☐ FAC-Neutral Test (D5) ☐ Surface Soil Cracks (B6) ☐ Stunted or Stressed Plants (D1) (LRR A) ☐ Raised Ant Mounds (D6) (LRR A) ☐ Inundation Visible on Aerial Imagery (B7) ☐ Other (explain in remarks) ☐ Frost-Heave Hummocks ☐ Sparsely Vegetated Concave Surface (B8) Field Observations: Wetland Hydrology Present? Yes ☐ No ☒ Surface Water Present? Yes ☐ No ☒ Depth (in): Water Table Present? Yes ☐ No ☒ Depth (in): Saturation Present? Yes ☐ No ☒ Depth (in): (includes capillary fringe) Describe Recorded Data (stream gauge, monitoring well, aerial photos, previous inspections), if available: Remarks: Completely dry US Army Corps of Engineers Western Mountains, Valleys, and Coast – Version 2.0 DP-8 Project/Site: Chelan Ave NE, Renton, WA City/County: Renton, WA Sampling date: 9/21/18 Applicant/Owner: Calvin Gasaway State: WA Sampling Point: 8 Investigator(s): L. Dougherty, P. Heltzel Section, Township, Range: 10, 23N, 05E Landform (hillslope, terrace, etc): Depression Local relief (concave, convex, none): Concave Slope (%): 0 Subregion (LRR): A Lat: Long: Datum: Soil Map Unit Name: Alderwood gravelly sandy loam, 8 to 15 percent slopes NWI classification: None Are climatic / hydrologic conditions on the site typical for this time of year? ☐ Yes ☒ No (If no, explain in remarks.) Are Vegetation ☐, Soil ☐, or Hydrology ☐ significantly disturbed? Are “Normal Circumstances” present on the site? ☒ Yes ☐ No Are Vegetation ☐, Soil ☐, or Hydrology ☐ naturally problematic? (If needed, explain any answers in Remarks.) SUMMARY OF FINDINGS – Attach site map showing sampling point locations, transects, important features, etc. Hydrophytic Vegetation Present? Yes ☒ No ☐ Is the Sampled Area within a Wetland? Yes ☒ No ☐ Hydric Soils Present? Yes ☒ No ☐ Wetland Hydrology Present? Yes ☒ No ☐ Remarks: Wetland B in-pit. Climatic conditions considered “drier than normal” per WETS table methodology. VEGETATION – Use scientific names of plants. Tree Stratum (Plot size: 5-m diameter) Absolute % Cover Dominant Species? Indicator Status Dominance Test worksheet: Number of Dominant Species that are OBL, FACW, or FAC: 3 (A) 1. Acer macrophyllum (rooted out) 75 - FACU 2. Alnus rubra 20 Y FAC Total Number of Dominant Species Across all Strata: 4 (B) 3. 4. Percent of Dominant Species that are OBL, FACW, or FAC: 75 (A/B) 95 = Total Cover Sapling/Shrub Stratum (Plot size: 3-m diameter) Prevalence Index worksheet: 1. Rubus armeniacus 5 Y FAC Total % Cover of: Multiply by: 2. OBL species x 1 = 3. FACW species x 2 = 4. FAC species x 3 = 5. FACU species x 4 = 5 = Total Cover UPL species x 5 = Herb Stratum (Plot size: 1-m diameter) Column Totals: (A) (B) 1. Ranunculus repens 85 Y FAC Prevalence Index = B/A = 2. Convolvulus arvensis 80 Y FACU 3. Phalaris arundinacea 20 N FACW Hydrophytic Vegetation Indicators: 4. ☐ 1 – Rapid Test for Hydrophytic Vegetation 5. ☒ 2 – Dominance Test is > 50% 6. ☐ 3 – Prevalence Index is ≤ 3.01 7. ☐ 4 – Morphological Adaptations1 (Provide supporting data in Remarks or on a separate sheet) 8. 9. ☐ 5 – Wetland Non-Vascular Plants1 10. ☐ Problematic Hydrophytic Vegetation1 (Explain) 11. 1Indicators of hydric soil and wetland hydrology must be present, unless disturbed or problematic. 185 = Total Cover Woody Vine Stratum (Plot size: 3-m diameter) Hydrophytic Vegetation Present? Yes ☒ No ☐ 1. 2. 0 = Total Cover % Bare Ground in Herb Stratum: 0 Remarks: WETLAND DETERMINATION DATA FORM – Western Mountains, Valleys, and Coast Region US Army Corps of Engineers Western Mountains, Valleys, and Coast – Version 2.0 SOIL Sampling Point: DP-8 HYDROLOGY Profile Description: (Describe to the depth needed to document the indicator or confirm the absence of indicators.) Depth Matrix Redox Features (inches) Color (moist) % Color (moist) % Type1 Loc2 Texture Remarks 0-7 10YR 2/1 100 Gravelly silt loam 7-10 10YR 2/1 96 10YR 5/2 7.5YR 4/4 3 1 D C M Silt loam 10-16 10YR 5/2 90 7.5YR 4/6 10 C M Gravelly silt loam 1Type: C=Concentration, D=Depletion, RM=Reduced Matrix, CS=Covered or Coated Sand Grains. 2Loc: PL=Pore Lining, M=Matrix. Hydric Soil Indicators: (Applicable to all LRRs, unless otherwise noted.) Indicators for Problematic Hydric Soils3: ☐ Histosol (A1) ☐ Sandy Redox (S5) ☐ 2cm Muck (A10) ☐ Histic Epipedon (A2) ☐ Stripped Matrix (S6) ☐ Red Parent Material (TF2) ☐ Black Histic (A3) ☐ Loamy Mucky Mineral (F1) (except MLRA 1) ☐ Very Shallow Dark Surface (TF12) ☐ Hydrogen Sulfide (A4) ☐ Loamy Gleyed Matrix (F2) ☐ Other (Explain in Remarks) ☐ Depleted Below Dark Surface (A11) ☒ Depleted Matrix (F3) ☐ Thick Dark Surface (A12) ☐ Redox Dark Surface (F6) 3 Indicators of hydrophytic vegetation and wetland hydrology must be present, unless disturbed or problematic. ☐ Sandy Mucky Mineral (S1) ☐ Depleted Dark Surface (F7) ☐ Sandy Gleyed Matrix (S4) ☐ Redox Depressions (F8) Restrictive Layer (if present): Hydric soil present? Yes ☒ No ☐ Type: Depth (inches): Remarks: Wetland Hydrology Indicators: Primary Indicators (minimum of one required: check all that apply) Secondary Indicators (2 or more required) ☐ Surface water (A1) ☐ Water-Stained Leaves (except MLRA 1, 2, 4A & 4B) (B9) ☒ Water-Stained Leaves (B9) (MLRA 1, 2, 4A & 4B) ☐ High Water Table (A2) ☐ Saturation (A3) ☐ Salt Crust (B11) ☐ Drainage Patterns (B10) ☐ Water Marks (B1) ☐ Aquatic Invertebrates (B13) ☐ Dry-Season Water Table (C2) ☐ Sediment Deposits (B2) ☐ Hydrogen Sulfide Odor (C1) ☐ Saturation Visible on Aerial Imagery (C9) ☐ Drift Deposits (B3) ☐ Oxidized Rhizospheres along Living Roots (C3) ☒ Geomorphic Position (D2) ☐ Algal Mat or Crust (B4) ☐ Presence of Reduced Iron (C4) ☐ Shallow Aquitard (D3) ☐ Iron Deposits (B5) ☐ Recent Iron Reduction in Tilled Soils (C6) ☐ FAC-Neutral Test (D5) ☐ Surface Soil Cracks (B6) ☐ Stunted or Stressed Plants (D1) (LRR A) ☐ Raised Ant Mounds (D6) (LRR A) ☐ Inundation Visible on Aerial Imagery (B7) ☐ Other (explain in remarks) ☐ Frost-Heave Hummocks ☐ Sparsely Vegetated Concave Surface (B8) Field Observations: Wetland Hydrology Present? Yes ☒ No ☐ Surface Water Present? Yes ☐ No ☒ Depth (in): Water Table Present? Yes ☐ No ☒ Depth (in): Saturation Present? Yes ☐ No ☒ Depth (in): (includes capillary fringe) Describe Recorded Data (stream gauge, monitoring well, aerial photos, previous inspections), if available: Remarks: Soil moist. US Army Corps of Engineers Western Mountains, Valleys, and Coast – Version 2.0 DP-9 Project/Site: Chelan Ave NE, Renton, WA City/County: Renton, WA Sampling date: 9/21/18 Applicant/Owner: Calvin Gasaway State: WA Sampling Point: 9 Investigator(s): L. Dougherty, P. Heltzel Section, Township, Range: 10, 23N, 05E Landform (hillslope, terrace, etc): Hillslope Local relief (concave, convex, none): None Slope (%): <5% Subregion (LRR): A Lat: Long: Datum: Soil Map Unit Name: Alderwood gravelly sandy loam, 8 to 15 percent slopes NWI classification: None Are climatic / hydrologic conditions on the site typical for this time of year? ☐ Yes ☒ No (If no, explain in remarks.) Are Vegetation ☐, Soil ☐, or Hydrology ☐ significantly disturbed? Are “Normal Circumstances” present on the site? ☒ Yes ☐ No Are Vegetation ☐, Soil ☐, or Hydrology ☐ naturally problematic? (If needed, explain any answers in Remarks.) SUMMARY OF FINDINGS – Attach site map showing sampling point locations, transects, important features, etc. Hydrophytic Vegetation Present? Yes ☒ No ☐ Is the Sampled Area within a Wetland? Yes ☐ No ☒ Hydric Soils Present? Yes ☐ No ☒ Wetland Hydrology Present? Yes ☐ No ☒ Remarks: Wetland B out-pit; SW of wetland unit. Climatic conditions considered “drier than normal” per WETS table methodology. VEGETATION – Use scientific names of plants. Tree Stratum (Plot size: 5-m diameter) Absolute % Cover Dominant Species? Indicator Status Dominance Test worksheet: Number of Dominant Species that are OBL, FACW, or FAC: 1 (A) 1. Acer macrophyllum 80 Y FACU 2. Total Number of Dominant Species Across all Strata: 2 (B) 3. 4. Percent of Dominant Species that are OBL, FACW, or FAC: 50 (A/B) 80 = Total Cover Sapling/Shrub Stratum (Plot size: 3-m diameter) Prevalence Index worksheet: 1. Total % Cover of: Multiply by: 2. OBL species x 1 = - 3. FACW species 100 x 2 = 200 4. FAC species 5 x 3 = 15 5. FACU species 90 x 4 = 360 0 = Total Cover UPL species x 5 = Herb Stratum (Plot size: 1-m diameter) Column Totals: 195 (A) 575 (B) 1. Phalaris arundinacea 100 Y FACW Prevalence Index = B/A = 2.94 2. Ranunculus repens 5 N FAC 3. Convolvulus arvensis 10 N FACU Hydrophytic Vegetation Indicators: 4. ☐ 1 – Rapid Test for Hydrophytic Vegetation 5. ☐ 2 – Dominance Test is > 50% 6. ☒ 3 – Prevalence Index is ≤ 3.01 7. ☐ 4 – Morphological Adaptations1 (Provide supporting data in Remarks or on a separate sheet) 8. 9. ☐ 5 – Wetland Non-Vascular Plants1 10. ☐ Problematic Hydrophytic Vegetation1 (Explain) 11. 1Indicators of hydric soil and wetland hydrology must be present, unless disturbed or problematic. 115 = Total Cover Woody Vine Stratum (Plot size: 3-m diameter) Hydrophytic Vegetation Present? Yes ☒ No ☐ 1. 2. 0 = Total Cover % Bare Ground in Herb Stratum: 0 Remarks: WETLAND DETERMINATION DATA FORM – Western Mountains, Valleys, and Coast Region US Army Corps of Engineers Western Mountains, Valleys, and Coast – Version 2.0 SOIL Sampling Point: DP-9 HYDROLOGY Profile Description: (Describe to the depth needed to document the indicator or confirm the absence of indicators.) Depth Matrix Redox Features (inches) Color (moist) % Color (moist) % Type1 Loc2 Texture Remarks 0-6 7.5YR 2.5/1 100 Sandy loam 6-16 10YR 3/2 100 Gravelly sandy loam 1Type: C=Concentration, D=Depletion, RM=Reduced Matrix, CS=Covered or Coated Sand Grains. 2Loc: PL=Pore Lining, M=Matrix. Hydric Soil Indicators: (Applicable to all LRRs, unless otherwise noted.) Indicators for Problematic Hydric Soils3: ☐ Histosol (A1) ☐ Sandy Redox (S5) ☐ 2cm Muck (A10) ☐ Histic Epipedon (A2) ☐ Stripped Matrix (S6) ☐ Red Parent Material (TF2) ☐ Black Histic (A3) ☐ Loamy Mucky Mineral (F1) (except MLRA 1) ☐ Very Shallow Dark Surface (TF12) ☐ Hydrogen Sulfide (A4) ☐ Loamy Gleyed Matrix (F2) ☐ Other (Explain in Remarks) ☐ Depleted Below Dark Surface (A11) ☐ Depleted Matrix (F3) ☐ Thick Dark Surface (A12) ☐ Redox Dark Surface (F6) 3 Indicators of hydrophytic vegetation and wetland hydrology must be present, unless disturbed or problematic. ☐ Sandy Mucky Mineral (S1) ☐ Depleted Dark Surface (F7) ☐ Sandy Gleyed Matrix (S4) ☐ Redox Depressions (F8) Restrictive Layer (if present): Hydric soil present? Yes ☐ No ☒ Type: Depth (inches): Remarks: Wetland Hydrology Indicators: Primary Indicators (minimum of one required: check all that apply) Secondary Indicators (2 or more required) ☐ Surface water (A1) ☐ Water-Stained Leaves (except MLRA 1, 2, 4A & 4B) (B9) ☐ Water-Stained Leaves (B9) (MLRA 1, 2, 4A & 4B) ☐ High Water Table (A2) ☐ Saturation (A3) ☐ Salt Crust (B11) ☐ Drainage Patterns (B10) ☐ Water Marks (B1) ☐ Aquatic Invertebrates (B13) ☐ Dry-Season Water Table (C2) ☐ Sediment Deposits (B2) ☐ Hydrogen Sulfide Odor (C1) ☐ Saturation Visible on Aerial Imagery (C9) ☐ Drift Deposits (B3) ☐ Oxidized Rhizospheres along Living Roots (C3) ☐ Geomorphic Position (D2) ☐ Algal Mat or Crust (B4) ☐ Presence of Reduced Iron (C4) ☐ Shallow Aquitard (D3) ☐ Iron Deposits (B5) ☐ Recent Iron Reduction in Tilled Soils (C6) ☐ FAC-Neutral Test (D5) ☐ Surface Soil Cracks (B6) ☐ Stunted or Stressed Plants (D1) (LRR A) ☐ Raised Ant Mounds (D6) (LRR A) ☐ Inundation Visible on Aerial Imagery (B7) ☐ Other (explain in remarks) ☐ Frost-Heave Hummocks ☐ Sparsely Vegetated Concave Surface (B8) Field Observations: Wetland Hydrology Present? Yes ☐ No ☒ Surface Water Present? Yes ☐ No ☒ Depth (in): Water Table Present? Yes ☐ No ☒ Depth (in): Saturation Present? Yes ☐ No ☒ Depth (in): (includes capillary fringe) Describe Recorded Data (stream gauge, monitoring well, aerial photos, previous inspections), if available: Remarks: Completely dry. US Army Corps of Engineers Western Mountains, Valleys, and Coast – Version 2.0 DP-10 Project/Site: Chelan Ave NE, Renton, WA City/County: Renton, WA Sampling date: 7/16/19 Applicant/Owner: Calvin Gasaway State: WA Sampling Point: 10 Investigator(s): L. Dougherty, G. Brennan Section, Township, Range: 10, 23N, 05E Landform (hillslope, terrace, etc): Swale Local relief (concave, convex, none): Concave Slope (%): 2% Subregion (LRR): A Lat: Long: Datum: Soil Map Unit Name: Alderwood gravelly sandy loam, 8 to 15 percent slopes NWI classification: None Are climatic / hydrologic conditions on the site typical for this time of year? ☐ Yes ☒ No (If no, explain in remarks.) Are Vegetation ☐, Soil ☐, or Hydrology ☐ significantly disturbed? Are “Normal Circumstances” present on the site? ☒ Yes ☐ No Are Vegetation ☐, Soil ☐, or Hydrology ☐ naturally problematic? (If needed, explain any answers in Remarks.) SUMMARY OF FINDINGS – Attach site map showing sampling point locations, transects, important features, etc. Hydrophytic Vegetation Present? Yes ☒ No ☐ Is the Sampled Area within a Wetland? Yes ☒ No ☐ Hydric Soils Present? Yes ☒ No ☐ Wetland Hydrology Present? Yes ☒ No ☐ Remarks: Wetland B in-pit -- north end of wetland unit. Climatic conditions considered “drier than normal” per WETS table methodology. VEGETATION – Use scientific names of plants. Tree Stratum (Plot size: 5-m diameter) Absolute % Cover Dominant Species? Indicator Status Dominance Test worksheet: Number of Dominant Species that are OBL, FACW, or FAC: 2 (A) 1. 2. Total Number of Dominant Species Across all Strata: 2 (B) 3. 4. Percent of Dominant Species that are OBL, FACW, or FAC: 100 (A/B) 0 = Total Cover Sapling/Shrub Stratum (Plot size: 3-m diameter) Prevalence Index worksheet: 1. Total % Cover of: Multiply by: 2. OBL species x 1 = - 3. FACW species x 2 = 4. FAC species x 3 = 5. FACU species x 4 = 0 = Total Cover UPL species x 5 = Herb Stratum (Plot size: 1-m diameter) Column Totals: (A) (B) 1. Ranunculus repens 60 Y FAC Prevalence Index = B/A = 2. Lawn grass 50 Y FAC* 3. Hydrophytic Vegetation Indicators: 4. ☐ 1 – Rapid Test for Hydrophytic Vegetation 5. ☒ 2 – Dominance Test is > 50% 6. ☐ 3 – Prevalence Index is ≤ 3.01 7. ☐ 4 – Morphological Adaptations1 (Provide supporting data in Remarks or on a separate sheet) 8. 9. ☐ 5 – Wetland Non-Vascular Plants1 10. ☐ Problematic Hydrophytic Vegetation1 (Explain) 11. 1Indicators of hydric soil and wetland hydrology must be present, unless disturbed or problematic. 110 = Total Cover Woody Vine Stratum (Plot size: 3-m diameter) Hydrophytic Vegetation Present? Yes ☒ No ☐ 1. 2. 0 = Total Cover % Bare Ground in Herb Stratum: 0 Remarks: *Presumed FAC indicator status WETLAND DETERMINATION DATA FORM – Western Mountains, Valleys, and Coast Region US Army Corps of Engineers Western Mountains, Valleys, and Coast – Version 2.0 SOIL Sampling Point: DP-10 HYDROLOGY Profile Description: (Describe to the depth needed to document the indicator or confirm the absence of indicators.) Depth Matrix Redox Features (inches) Color (moist) % Color (moist) % Type1 Loc2 Texture Remarks 0-12 10YR 2/1 100 Sandy loam 12-18 10YR 4/2 95 7.5YR 4/6 5 C M Sandy loam 1Type: C=Concentration, D=Depletion, RM=Reduced Matrix, CS=Covered or Coated Sand Grains. 2Loc: PL=Pore Lining, M=Matrix. Hydric Soil Indicators: (Applicable to all LRRs, unless otherwise noted.) Indicators for Problematic Hydric Soils3: ☐ Histosol (A1) ☐ Sandy Redox (S5) ☐ 2cm Muck (A10) ☐ Histic Epipedon (A2) ☐ Stripped Matrix (S6) ☐ Red Parent Material (TF2) ☐ Black Histic (A3) ☐ Loamy Mucky Mineral (F1) (except MLRA 1) ☐ Very Shallow Dark Surface (TF12) ☐ Hydrogen Sulfide (A4) ☐ Loamy Gleyed Matrix (F2) ☐ Other (Explain in Remarks) ☐ Depleted Below Dark Surface (A11) ☐ Depleted Matrix (F3) ☒ Thick Dark Surface (A12) ☐ Redox Dark Surface (F6) 3 Indicators of hydrophytic vegetation and wetland hydrology must be present, unless disturbed or problematic. ☐ Sandy Mucky Mineral (S1) ☐ Depleted Dark Surface (F7) ☐ Sandy Gleyed Matrix (S4) ☐ Redox Depressions (F8) Restrictive Layer (if present): Hydric soil present? Yes ☒ No ☐ Type: Depth (inches): Remarks: Wetland Hydrology Indicators: Primary Indicators (minimum of one required: check all that apply) Secondary Indicators (2 or more required) ☐ Surface water (A1) ☐ Water-Stained Leaves (except MLRA 1, 2, 4A & 4B) (B9) ☒ Water-Stained Leaves (B9) (MLRA 1, 2, 4A & 4B) ☐ High Water Table (A2) ☐ Saturation (A3) ☐ Salt Crust (B11) ☐ Drainage Patterns (B10) ☐ Water Marks (B1) ☐ Aquatic Invertebrates (B13) ☐ Dry-Season Water Table (C2) ☐ Sediment Deposits (B2) ☐ Hydrogen Sulfide Odor (C1) ☐ Saturation Visible on Aerial Imagery (C9) ☐ Drift Deposits (B3) ☐ Oxidized Rhizospheres along Living Roots (C3) ☒ Geomorphic Position (D2) ☐ Algal Mat or Crust (B4) ☐ Presence of Reduced Iron (C4) ☐ Shallow Aquitard (D3) ☐ Iron Deposits (B5) ☐ Recent Iron Reduction in Tilled Soils (C6) ☐ FAC-Neutral Test (D5) ☐ Surface Soil Cracks (B6) ☐ Stunted or Stressed Plants (D1) (LRR A) ☐ Raised Ant Mounds (D6) (LRR A) ☐ Inundation Visible on Aerial Imagery (B7) ☐ Other (explain in remarks) ☐ Frost-Heave Hummocks ☐ Sparsely Vegetated Concave Surface (B8) Field Observations: Wetland Hydrology Present? Yes ☒ No ☐ Surface Water Present? Yes ☐ No ☒ Depth (in): Water Table Present? Yes ☐ No ☒ Depth (in): Saturation Present? Yes ☐ No ☒ Depth (in): (includes capillary fringe) Describe Recorded Data (stream gauge, monitoring well, aerial photos, previous inspections), if available: Remarks: Several wooden boards placed perpendicularly across swale indicate that the feature is likely inundated at some point during the year. US Army Corps of Engineers Western Mountains, Valleys, and Coast – Version 2.0 DP-11 Project/Site: Chelan Ave NE, Renton, WA City/County: Renton, WA Sampling date: 7/16/19 Applicant/Owner: Calvin Gasaway State: WA Sampling Point: 11 Investigator(s): L. Dougherty, G. Brennan Section, Township, Range: 10, 23N, 05E Landform (hillslope, terrace, etc): Hillslope Local relief (concave, convex, none): None Slope (%): 1% Subregion (LRR): A Lat: Long: Datum: Soil Map Unit Name: Alderwood gravelly sandy loam, 8 to 15 percent slopes NWI classification: None Are climatic / hydrologic conditions on the site typical for this time of year? ☐ Yes ☒ No (If no, explain in remarks.) Are Vegetation ☐, Soil ☐, or Hydrology ☐ significantly disturbed? Are “Normal Circumstances” present on the site? ☒ Yes ☐ No Are Vegetation ☐, Soil ☐, or Hydrology ☐ naturally problematic? (If needed, explain any answers in Remarks.) SUMMARY OF FINDINGS – Attach site map showing sampling point locations, transects, important features, etc. Hydrophytic Vegetation Present? Yes ☐ No ☒ Is the Sampled Area within a Wetland? Yes ☐ No ☒ Hydric Soils Present? Yes ☐ No ☒ Wetland Hydrology Present? Yes ☐ No ☒ Remarks: Wetland B out-pit – west of north end of wetland unit. Climatic conditions considered “drier than normal” per WETS table methodology. VEGETATION – Use scientific names of plants. Tree Stratum (Plot size: 5-m diameter) Absolute % Cover Dominant Species? Indicator Status Dominance Test worksheet: Number of Dominant Species that are OBL, FACW, or FAC: 1 (A) 1. Pseudotsuga menziesii 25 Y FACU 2. Total Number of Dominant Species Across all Strata: 2 (B) 3. 4. Percent of Dominant Species that are OBL, FACW, or FAC: 50 (A/B) 25 = Total Cover Sapling/Shrub Stratum (Plot size: 3-m diameter) Prevalence Index worksheet: 1. Total % Cover of: Multiply by: 2. OBL species x 1 = - 3. FACW species x 2 = 4. FAC species 70 x 3 = 210 5. FACU species 25 x 4 = 100 0 = Total Cover UPL species x 5 = Herb Stratum (Plot size: 1-m diameter) Column Totals: 95 (A) 310 (B) 1. Lawn grass 70 Y FAC* Prevalence Index = B/A = 3.3 2. 3. Hydrophytic Vegetation Indicators: 4. ☐ 1 – Rapid Test for Hydrophytic Vegetation 5. ☐ 2 – Dominance Test is > 50% 6. ☐ 3 – Prevalence Index is ≤ 3.01 7. ☐ 4 – Morphological Adaptations1 (Provide supporting data in Remarks or on a separate sheet) 8. 9. ☐ 5 – Wetland Non-Vascular Plants1 10. ☐ Problematic Hydrophytic Vegetation1 (Explain) 11. 1Indicators of hydric soil and wetland hydrology must be present, unless disturbed or problematic. 70 = Total Cover Woody Vine Stratum (Plot size: 3-m diameter) Hydrophytic Vegetation Present? Yes ☐ No ☒ 1. 2. 0 = Total Cover % Bare Ground in Herb Stratum: 0** Remarks: *Presumed FAC indicator status. *Heavy moss cover in lawn. WETLAND DETERMINATION DATA FORM – Western Mountains, Valleys, and Coast Region US Army Corps of Engineers Western Mountains, Valleys, and Coast – Version 2.0 SOIL Sampling Point: DP-11 HYDROLOGY Profile Description: (Describe to the depth needed to document the indicator or confirm the absence of indicators.) Depth Matrix Redox Features (inches) Color (moist) % Color (moist) % Type1 Loc2 Texture Remarks 0-16 10YR 2/1 100 Sandy loam 1Type: C=Concentration, D=Depletion, RM=Reduced Matrix, CS=Covered or Coated Sand Grains. 2Loc: PL=Pore Lining, M=Matrix. Hydric Soil Indicators: (Applicable to all LRRs, unless otherwise noted.) Indicators for Problematic Hydric Soils3: ☐ Histosol (A1) ☐ Sandy Redox (S5) ☐ 2cm Muck (A10) ☐ Histic Epipedon (A2) ☐ Stripped Matrix (S6) ☐ Red Parent Material (TF2) ☐ Black Histic (A3) ☐ Loamy Mucky Mineral (F1) (except MLRA 1) ☐ Very Shallow Dark Surface (TF12) ☐ Hydrogen Sulfide (A4) ☐ Loamy Gleyed Matrix (F2) ☐ Other (Explain in Remarks) ☐ Depleted Below Dark Surface (A11) ☐ Depleted Matrix (F3) ☐ Thick Dark Surface (A12) ☐ Redox Dark Surface (F6) 3 Indicators of hydrophytic vegetation and wetland hydrology must be present, unless disturbed or problematic. ☐ Sandy Mucky Mineral (S1) ☐ Depleted Dark Surface (F7) ☐ Sandy Gleyed Matrix (S4) ☐ Redox Depressions (F8) Restrictive Layer (if present): Hydric soil present? Yes ☐ No ☒ Type: Depth (inches): Remarks: Wetland Hydrology Indicators: Primary Indicators (minimum of one required: check all that apply) Secondary Indicators (2 or more required) ☐ Surface water (A1) ☐ Water-Stained Leaves (except MLRA 1, 2, 4A & 4B) (B9) ☐ Water-Stained Leaves (B9) (MLRA 1, 2, 4A & 4B) ☐ High Water Table (A2) ☐ Saturation (A3) ☐ Salt Crust (B11) ☐ Drainage Patterns (B10) ☐ Water Marks (B1) ☐ Aquatic Invertebrates (B13) ☐ Dry-Season Water Table (C2) ☐ Sediment Deposits (B2) ☐ Hydrogen Sulfide Odor (C1) ☐ Saturation Visible on Aerial Imagery (C9) ☐ Drift Deposits (B3) ☐ Oxidized Rhizospheres along Living Roots (C3) ☐ Geomorphic Position (D2) ☐ Algal Mat or Crust (B4) ☐ Presence of Reduced Iron (C4) ☐ Shallow Aquitard (D3) ☐ Iron Deposits (B5) ☐ Recent Iron Reduction in Tilled Soils (C6) ☐ FAC-Neutral Test (D5) ☐ Surface Soil Cracks (B6) ☐ Stunted or Stressed Plants (D1) (LRR A) ☐ Raised Ant Mounds (D6) (LRR A) ☐ Inundation Visible on Aerial Imagery (B7) ☐ Other (explain in remarks) ☐ Frost-Heave Hummocks ☐ Sparsely Vegetated Concave Surface (B8) Field Observations: Wetland Hydrology Present? Yes ☐ No ☒ Surface Water Present? Yes ☐ No ☒ Depth (in): Water Table Present? Yes ☐ No ☒ Depth (in): Saturation Present? Yes ☐ No ☒ Depth (in): (includes capillary fringe) Describe Recorded Data (stream gauge, monitoring well, aerial photos, previous inspections), if available: Remarks: US Army Corps of Engineers Western Mountains, Valleys, and Coast – Version 2.0 DP-12 Project/Site: Chelan Ave NE, Renton, WA City/County: Renton, WA Sampling date: 7/16/19 Applicant/Owner: Calvin Gasaway State: WA Sampling Point: 12 Investigator(s): L. Dougherty, G. Brennan Section, Township, Range: 10, 23N, 05E Landform (hillslope, terrace, etc): Hillslope Local relief (concave, convex, none): None Slope (%): 15 Subregion (LRR): A Lat: Long: Datum: Soil Map Unit Name: Alderwood gravelly sandy loam, 8 to 15 percent slopes NWI classification: None Are climatic / hydrologic conditions on the site typical for this time of year? ☐ Yes ☒ No (If no, explain in remarks.) Are Vegetation ☐, Soil ☐, or Hydrology ☐ significantly disturbed? Are “Normal Circumstances” present on the site? ☒ Yes ☐ No Are Vegetation ☐, Soil ☐, or Hydrology ☐ naturally problematic? (If needed, explain any answers in Remarks.) SUMMARY OF FINDINGS – Attach site map showing sampling point locations, transects, important features, etc. Hydrophytic Vegetation Present? Yes ☐ No ☒ Is the Sampled Area within a Wetland? Yes ☐ No ☒ Hydric Soils Present? Yes ☐ No ☒ Wetland Hydrology Present? Yes ☐ No ☒ Remarks: Wetland C out-pit – east of north end of wetland unit. Climatic conditions considered “drier than normal” per WETS table methodology. VEGETATION – Use scientific names of plants. Tree Stratum (Plot size: 5-m diameter) Absolute % Cover Dominant Species? Indicator Status Dominance Test worksheet: Number of Dominant Species that are OBL, FACW, or FAC: 1 (A) 1. 2. Total Number of Dominant Species Across all Strata: 3 (B) 3. 4. Percent of Dominant Species that are OBL, FACW, or FAC: 33 (A/B) 0 = Total Cover Sapling/Shrub Stratum (Plot size: 3-m diameter) Prevalence Index worksheet: 1. Total % Cover of: Multiply by: 2. OBL species x 1 = - 3. FACW species x 2 = 4. FAC species x 3 = 5. FACU species x 4 = 0 = Total Cover UPL species x 5 = Herb Stratum (Plot size: 1-m diameter) Column Totals: (A) (B) 1. Taraxacum officinale 15 Y FACU Prevalence Index = B/A = 2. Dactylis glomerata 40 Y FACU 3. Lawn grass 15 Y FAC* Hydrophytic Vegetation Indicators: 4. ☐ 1 – Rapid Test for Hydrophytic Vegetation 5. ☐ 2 – Dominance Test is > 50% 6. ☐ 3 – Prevalence Index is ≤ 3.01 7. ☐ 4 – Morphological Adaptations1 (Provide supporting data in Remarks or on a separate sheet) 8. 9. ☐ 5 – Wetland Non-Vascular Plants1 10. ☐ Problematic Hydrophytic Vegetation1 (Explain) 11. 1Indicators of hydric soil and wetland hydrology must be present, unless disturbed or problematic. 70 = Total Cover Woody Vine Stratum (Plot size: 3-m diameter) Hydrophytic Vegetation Present? Yes ☐ No ☒ 1. 2. 0 = Total Cover % Bare Ground in Herb Stratum: 0** Remarks: *Presumed FAC indicator status **Lots of grass clippings/duff in lawn WETLAND DETERMINATION DATA FORM – Western Mountains, Valleys, and Coast Region US Army Corps of Engineers Western Mountains, Valleys, and Coast – Version 2.0 SOIL Sampling Point: DP-12 HYDROLOGY Profile Description: (Describe to the depth needed to document the indicator or confirm the absence of indicators.) Depth Matrix Redox Features (inches) Color (moist) % Color (moist) % Type1 Loc2 Texture Remarks 0-14 10YR 2/2 100 Gravelly loamy sand 1Type: C=Concentration, D=Depletion, RM=Reduced Matrix, CS=Covered or Coated Sand Grains. 2Loc: PL=Pore Lining, M=Matrix. Hydric Soil Indicators: (Applicable to all LRRs, unless otherwise noted.) Indicators for Problematic Hydric Soils3: ☐ Histosol (A1) ☐ Sandy Redox (S5) ☐ 2cm Muck (A10) ☐ Histic Epipedon (A2) ☐ Stripped Matrix (S6) ☐ Red Parent Material (TF2) ☐ Black Histic (A3) ☐ Loamy Mucky Mineral (F1) (except MLRA 1) ☐ Very Shallow Dark Surface (TF12) ☐ Hydrogen Sulfide (A4) ☐ Loamy Gleyed Matrix (F2) ☐ Other (Explain in Remarks) ☐ Depleted Below Dark Surface (A11) ☐ Depleted Matrix (F3) ☐ Thick Dark Surface (A12) ☐ Redox Dark Surface (F6) 3 Indicators of hydrophytic vegetation and wetland hydrology must be present, unless disturbed or problematic. ☐ Sandy Mucky Mineral (S1) ☐ Depleted Dark Surface (F7) ☐ Sandy Gleyed Matrix (S4) ☐ Redox Depressions (F8) Restrictive Layer (if present): Hydric soil present? Yes ☐ No ☒ Type: Depth (inches): Remarks: Wetland Hydrology Indicators: Primary Indicators (minimum of one required: check all that apply) Secondary Indicators (2 or more required) ☐ Surface water (A1) ☐ Water-Stained Leaves (except MLRA 1, 2, 4A & 4B) (B9) ☐ Water-Stained Leaves (B9) (MLRA 1, 2, 4A & 4B) ☐ High Water Table (A2) ☐ Saturation (A3) ☐ Salt Crust (B11) ☐ Drainage Patterns (B10) ☐ Water Marks (B1) ☐ Aquatic Invertebrates (B13) ☐ Dry-Season Water Table (C2) ☐ Sediment Deposits (B2) ☐ Hydrogen Sulfide Odor (C1) ☐ Saturation Visible on Aerial Imagery (C9) ☐ Drift Deposits (B3) ☐ Oxidized Rhizospheres along Living Roots (C3) ☐ Geomorphic Position (D2) ☐ Algal Mat or Crust (B4) ☐ Presence of Reduced Iron (C4) ☐ Shallow Aquitard (D3) ☐ Iron Deposits (B5) ☐ Recent Iron Reduction in Tilled Soils (C6) ☐ FAC-Neutral Test (D5) ☐ Surface Soil Cracks (B6) ☐ Stunted or Stressed Plants (D1) (LRR A) ☐ Raised Ant Mounds (D6) (LRR A) ☐ Inundation Visible on Aerial Imagery (B7) ☐ Other (explain in remarks) ☐ Frost-Heave Hummocks ☐ Sparsely Vegetated Concave Surface (B8) Field Observations: Wetland Hydrology Present? Yes ☐ No ☒ Surface Water Present? Yes ☐ No ☒ Depth (in): Water Table Present? Yes ☐ No ☒ Depth (in): Saturation Present? Yes ☐ No ☒ Depth (in): (includes capillary fringe) Describe Recorded Data (stream gauge, monitoring well, aerial photos, previous inspections), if available: Remarks: US Army Corps of Engineers Western Mountains, Valleys, and Coast – Version 2.0 DP-13 Project/Site: Chelan Ave NE, Renton, WA City/County: Renton, WA Sampling date: 7/16/19 Applicant/Owner: Calvin Gasaway State: WA Sampling Point: 13 Investigator(s): L. Dougherty, G. Brennan Section, Township, Range: 10, 23N, 05E Landform (hillslope, terrace, etc): Terrace Local relief (concave, convex, none): Concave Slope (%): 0% Subregion (LRR): A Lat: Long: Datum: Soil Map Unit Name: Alderwood gravelly sandy loam, 8 to 15 percent slopes NWI classification: None Are climatic / hydrologic conditions on the site typical for this time of year? ☐ Yes ☒ No (If no, explain in remarks.) Are Vegetation ☐, Soil ☐, or Hydrology ☐ significantly disturbed? Are “Normal Circumstances” present on the site? ☒ Yes ☐ No Are Vegetation ☐, Soil ☐, or Hydrology ☐ naturally problematic? (If needed, explain any answers in Remarks.) SUMMARY OF FINDINGS – Attach site map showing sampling point locations, transects, important features, etc. Hydrophytic Vegetation Present? Yes ☒ No ☐ Is the Sampled Area within a Wetland? Yes ☐ No ☒ Hydric Soils Present? Yes ☐ No ☒ Wetland Hydrology Present? Yes ☐ No ☒ Remarks: Wetland C out-pit – west of north end of wetland unit. Climatic conditions considered “drier than normal” per WETS table methodology. VEGETATION – Use scientific names of plants. Tree Stratum (Plot size: 5-m diameter) Absolute % Cover Dominant Species? Indicator Status Dominance Test worksheet: Number of Dominant Species that are OBL, FACW, or FAC: 2 (A) 1. 2. Total Number of Dominant Species Across all Strata: 3 (B) 3. 4. Percent of Dominant Species that are OBL, FACW, or FAC: 67 (A/B) 0 = Total Cover Sapling/Shrub Stratum (Plot size: 3-m diameter) Prevalence Index worksheet: 1. Total % Cover of: Multiply by: 2. OBL species x 1 = - 3. FACW species x 2 = 4. FAC species x 3 = 5. FACU species x 4 = 0 = Total Cover UPL species x 5 = Herb Stratum (Plot size: 1-m diameter) Column Totals: (A) (B) 1. Holcus lanatus 25 Y FAC Prevalence Index = B/A = 2. Taraxacum officinale 20 Y FACU 3. Ranunculus acris 20 Y FAC Hydrophytic Vegetation Indicators: 4. Ranunculus repens 10 N FAC ☐ 1 – Rapid Test for Hydrophytic Vegetation 5. ☒ 2 – Dominance Test is > 50% 6. ☐ 3 – Prevalence Index is ≤ 3.01 7. ☐ 4 – Morphological Adaptations1 (Provide supporting data in Remarks or on a separate sheet) 8. 9. ☐ 5 – Wetland Non-Vascular Plants1 10. ☐ Problematic Hydrophytic Vegetation1 (Explain) 11. 1Indicators of hydric soil and wetland hydrology must be present, unless disturbed or problematic. 75 = Total Cover Woody Vine Stratum (Plot size: 3-m diameter) Hydrophytic Vegetation Present? Yes ☒ No ☐ 1. 2. 0 = Total Cover % Bare Ground in Herb Stratum: 0* Remarks: *Lawn clippings/duff groundcover. WETLAND DETERMINATION DATA FORM – Western Mountains, Valleys, and Coast Region US Army Corps of Engineers Western Mountains, Valleys, and Coast – Version 2.0 SOIL Sampling Point: DP-13 HYDROLOGY Profile Description: (Describe to the depth needed to document the indicator or confirm the absence of indicators.) Depth Matrix Redox Features (inches) Color (moist) % Color (moist) % Type1 Loc2 Texture Remarks 0-14 10YR 2/1 100 Silt loam Dense grass root system in layer 14-18 2.5Y 4/2 30* Clay loam Mixed matrix 2.5Y 3/1 30* 1Type: C=Concentration, D=Depletion, RM=Reduced Matrix, CS=Covered or Coated Sand Grains. 2Loc: PL=Pore Lining, M=Matrix. Hydric Soil Indicators: (Applicable to all LRRs, unless otherwise noted.) Indicators for Problematic Hydric Soils3: ☐ Histosol (A1) ☐ Sandy Redox (S5) ☐ 2cm Muck (A10) ☐ Histic Epipedon (A2) ☐ Stripped Matrix (S6) ☐ Red Parent Material (TF2) ☐ Black Histic (A3) ☐ Loamy Mucky Mineral (F1) (except MLRA 1) ☐ Very Shallow Dark Surface (TF12) ☐ Hydrogen Sulfide (A4) ☐ Loamy Gleyed Matrix (F2) ☐ Other (Explain in Remarks) ☐ Depleted Below Dark Surface (A11) ☐ Depleted Matrix (F3) ☐ Thick Dark Surface (A12) ☐ Redox Dark Surface (F6) 3 Indicators of hydrophytic vegetation and wetland hydrology must be present, unless disturbed or problematic. ☐ Sandy Mucky Mineral (S1) ☐ Depleted Dark Surface (F7) ☐ Sandy Gleyed Matrix (S4) ☐ Redox Depressions (F8) Restrictive Layer (if present): Hydric soil present? Yes ☐ No ☒ Type: Depth (inches): Remarks: *Charcoal inclusions ~30% in 14-18” layer Wetland Hydrology Indicators: Primary Indicators (minimum of one required: check all that apply) Secondary Indicators (2 or more required) ☐ Surface water (A1) ☐ Water-Stained Leaves (except MLRA 1, 2, 4A & 4B) (B9) ☐ Water-Stained Leaves (B9) (MLRA 1, 2, 4A & 4B) ☐ High Water Table (A2) ☐ Saturation (A3) ☐ Salt Crust (B11) ☐ Drainage Patterns (B10) ☐ Water Marks (B1) ☐ Aquatic Invertebrates (B13) ☐ Dry-Season Water Table (C2) ☐ Sediment Deposits (B2) ☐ Hydrogen Sulfide Odor (C1) ☐ Saturation Visible on Aerial Imagery (C9) ☐ Drift Deposits (B3) ☐ Oxidized Rhizospheres along Living Roots (C3) ☐ Geomorphic Position (D2) ☐ Algal Mat or Crust (B4) ☐ Presence of Reduced Iron (C4) ☐ Shallow Aquitard (D3) ☐ Iron Deposits (B5) ☐ Recent Iron Reduction in Tilled Soils (C6) ☐ FAC-Neutral Test (D5) ☐ Surface Soil Cracks (B6) ☐ Stunted or Stressed Plants (D1) (LRR A) ☐ Raised Ant Mounds (D6) (LRR A) ☐ Inundation Visible on Aerial Imagery (B7) ☐ Other (explain in remarks) ☐ Frost-Heave Hummocks ☐ Sparsely Vegetated Concave Surface (B8) Field Observations: Wetland Hydrology Present? Yes ☐ No ☒ Surface Water Present? Yes ☐ No ☒ Depth (in): Water Table Present? Yes ☐ No ☒ Depth (in): Saturation Present? Yes ☐ No ☒ Depth (in): (includes capillary fringe) Describe Recorded Data (stream gauge, monitoring well, aerial photos, previous inspections), if available: Remarks: US Army Corps of Engineers Western Mountains, Valleys, and Coast – Version 2.0 DP-14 Project/Site: Chelan Ave NE, Renton, WA City/County: Renton, WA Sampling date: 7/16/19 Applicant/Owner: Calvin Gasaway State: WA Sampling Point: 14 Investigator(s): L. Dougherty, G. Brennan Section, Township, Range: 10, 23N, 05E Landform (hillslope, terrace, etc): Swale Local relief (concave, convex, none): Concave Slope (%): 5% Subregion (LRR): A Lat: Long: Datum: Soil Map Unit Name: Alderwood gravelly sandy loam, 8 to 15 percent slopes NWI classification: None Are climatic / hydrologic conditions on the site typical for this time of year? ☐ Yes ☒ No (If no, explain in remarks.) Are Vegetation ☐, Soil ☐, or Hydrology ☐ significantly disturbed? Are “Normal Circumstances” present on the site? ☒ Yes ☐ No Are Vegetation ☐, Soil ☐, or Hydrology ☐ naturally problematic? (If needed, explain any answers in Remarks.) SUMMARY OF FINDINGS – Attach site map showing sampling point locations, transects, important features, etc. Hydrophytic Vegetation Present? Yes ☒ No ☐ Is the Sampled Area within a Wetland? Yes ☒ No ☐ Hydric Soils Present? Yes ☒ No ☐ Wetland Hydrology Present? Yes ☒ No ☐ Remarks: Wetland C in-pit – north end of wetland unit. Climatic conditions considered “drier than normal” per WETS table methodology. VEGETATION – Use scientific names of plants. Tree Stratum (Plot size: 5-m diameter) Absolute % Cover Dominant Species? Indicator Status Dominance Test worksheet: Number of Dominant Species that are OBL, FACW, or FAC: 2 (A) 1. Populus balsamifera 15 Y FAC 2. Total Number of Dominant Species Across all Strata: 2 (B) 3. 4. Percent of Dominant Species that are OBL, FACW, or FAC: 100 (A/B) 15 = Total Cover Sapling/Shrub Stratum (Plot size: 3-m diameter) Prevalence Index worksheet: 1. Populus balsamifera (sapling) 40 Y FAC Total % Cover of: Multiply by: 2. OBL species x 1 = - 3. FACW species x 2 = 4. FAC species x 3 = 5. FACU species x 4 = 40 = Total Cover UPL species x 5 = Herb Stratum (Plot size: 1-m diameter) Column Totals: (A) (B) 1. Ranunculus repens 70 Y FAC Prevalence Index = B/A = 2. Lawn grass 10 N FAC* 3. Juncus effusus 5 N FACW Hydrophytic Vegetation Indicators: 4. ☐ 1 – Rapid Test for Hydrophytic Vegetation 5. ☒ 2 – Dominance Test is > 50% 6. ☐ 3 – Prevalence Index is ≤ 3.01 7. ☐ 4 – Morphological Adaptations1 (Provide supporting data in Remarks or on a separate sheet) 8. 9. ☐ 5 – Wetland Non-Vascular Plants1 10. ☐ Problematic Hydrophytic Vegetation1 (Explain) 11. 1Indicators of hydric soil and wetland hydrology must be present, unless disturbed or problematic. 85 = Total Cover Woody Vine Stratum (Plot size: 3-m diameter) Hydrophytic Vegetation Present? Yes ☒ No ☐ 1. 2. 0 = Total Cover % Bare Ground in Herb Stratum: 0** Remarks: *Presumed FAC indicator status **Lawn clippings/duff groundcover. WETLAND DETERMINATION DATA FORM – Western Mountains, Valleys, and Coast Region US Army Corps of Engineers Western Mountains, Valleys, and Coast – Version 2.0 SOIL Sampling Point: DP-14 HYDROLOGY Profile Description: (Describe to the depth needed to document the indicator or confirm the absence of indicators.) Depth Matrix Redox Features (inches) Color (moist) % Color (moist) % Type1 Loc2 Texture Remarks 0-6 10YR 2/2 100 Sandy loam Dense grass root system 6-9 10YR 3/2 95 7.5YR 4/6 5 C M Sandy loam 9-14 2.5Y 3/2 93 7.5YR 4/4 7 C M, PL Sandy loam 1Type: C=Concentration, D=Depletion, RM=Reduced Matrix, CS=Covered or Coated Sand Grains. 2Loc: PL=Pore Lining, M=Matrix. Hydric Soil Indicators: (Applicable to all LRRs, unless otherwise noted.) Indicators for Problematic Hydric Soils3: ☐ Histosol (A1) ☐ Sandy Redox (S5) ☐ 2cm Muck (A10) ☐ Histic Epipedon (A2) ☐ Stripped Matrix (S6) ☐ Red Parent Material (TF2) ☐ Black Histic (A3) ☐ Loamy Mucky Mineral (F1) (except MLRA 1) ☐ Very Shallow Dark Surface (TF12) ☐ Hydrogen Sulfide (A4) ☐ Loamy Gleyed Matrix (F2) ☐ Other (Explain in Remarks) ☐ Depleted Below Dark Surface (A11) ☐ Depleted Matrix (F3) ☐ Thick Dark Surface (A12) ☒ Redox Dark Surface (F6) 3 Indicators of hydrophytic vegetation and wetland hydrology must be present, unless disturbed or problematic. ☐ Sandy Mucky Mineral (S1) ☐ Depleted Dark Surface (F7) ☐ Sandy Gleyed Matrix (S4) ☐ Redox Depressions (F8) Restrictive Layer (if present): Hydric soil present? Yes ☒ No ☐ Type: Depth (inches): Remarks: Wetland Hydrology Indicators: Primary Indicators (minimum of one required: check all that apply) Secondary Indicators (2 or more required) ☐ Surface water (A1) ☐ Water-Stained Leaves (except MLRA 1, 2, 4A & 4B) (B9) ☐ Water-Stained Leaves (B9) (MLRA 1, 2, 4A & 4B) ☐ High Water Table (A2) ☐ Saturation (A3) ☐ Salt Crust (B11) ☐ Drainage Patterns (B10) ☐ Water Marks (B1) ☐ Aquatic Invertebrates (B13) ☐ Dry-Season Water Table (C2) ☐ Sediment Deposits (B2) ☐ Hydrogen Sulfide Odor (C1) ☒ Saturation Visible on Aerial Imagery (C9) ☐ Drift Deposits (B3) ☒ Oxidized Rhizospheres along Living Roots (C3) ☒ Geomorphic Position (D2) ☐ Algal Mat or Crust (B4) ☐ Presence of Reduced Iron (C4) ☐ Shallow Aquitard (D3) ☐ Iron Deposits (B5) ☐ Recent Iron Reduction in Tilled Soils (C6) ☐ FAC-Neutral Test (D5) ☐ Surface Soil Cracks (B6) ☐ Stunted or Stressed Plants (D1) (LRR A) ☐ Raised Ant Mounds (D6) (LRR A) ☐ Inundation Visible on Aerial Imagery (B7) ☐ Other (explain in remarks) ☐ Frost-Heave Hummocks ☐ Sparsely Vegetated Concave Surface (B8) Field Observations: Wetland Hydrology Present? Yes ☒ No ☐ Surface Water Present? Yes ☐ No ☒ Depth (in): Water Table Present? Yes ☐ No ☒ Depth (in): Saturation Present? Yes ☐ No ☒ Depth (in): (includes capillary fringe) Describe Recorded Data (stream gauge, monitoring well, aerial photos, previous inspections), if available: Remarks: US Army Corps of Engineers Western Mountains, Valleys, and Coast – Version 2.0 DP-15 Project/Site: Chelan Ave NE, Renton, WA City/County: Renton, WA Sampling date: 9/27/19 Applicant/Owner: Calvin Gasaway State: WA Sampling Point: 15 Investigator(s): L. Dougherty, P. Heltzel Section, Township, Range: 10, 23N, 05E Landform (hillslope, terrace, etc): Depression Local relief (concave, convex, none): None Slope (%): 0 Subregion (LRR): A Lat: Long: Datum: Soil Map Unit Name: Alderwood gravelly sandy loam, 8 to 15 percent slopes NWI classification: None Are climatic / hydrologic conditions on the site typical for this time of year? ☐ Yes ☒ No (If no, explain in remarks.) Are Vegetation ☐, Soil ☐, or Hydrology ☐ significantly disturbed? Are “Normal Circumstances” present on the site? ☒ Yes ☐ No Are Vegetation ☐, Soil ☐, or Hydrology ☐ naturally problematic? (If needed, explain any answers in Remarks.) SUMMARY OF FINDINGS – Attach site map showing sampling point locations, transects, important features, etc. Hydrophytic Vegetation Present? Yes ☒ No ☐ Is the Sampled Area within a Wetland? Yes ☒No ☐Hydric Soils Present? Yes ☒ No ☐ Wetland Hydrology Present? Yes ☒ No ☐ Remarks: Wetland C in-pit, parcel no. 1023059107 Climatic conditions considered “wetter than normal” per WETS table methodology. VEGETATION – Use scientific names of plants. Tree Stratum (Plot size: 5-m diameter) Absolute % Cover Dominant Species? Indicator Status Dominance Test worksheet: Number of Dominant Species that are OBL, FACW, or FAC: 4 (A) 1.Fraxinus latifolia 60 Y FACW 2.Populus balsamifera 75 Y FAC Total Number of Dominant Species Across all Strata: 4 (B) 3. 4. Percent of Dominant Species that are OBL, FACW, or FAC: 100 (A/B) 135 = Total Cover Sapling/Shrub Stratum (Plot size: 3-m diameter) Prevalence Index worksheet: 1.Fraxinus latifolia 50 Y FACW Total % Cover of: Multiply by: 2.Spiraea douglasii 15 Y FACW OBL species x 1 = 3. FACW species x 2 = 4. FAC species x 3 = 5. FACU species x 4 = 0 = Total Cover UPL species x 5 = Herb Stratum (Plot size: 1-m diameter) Column Totals: (A) (B) 1. Prevalence Index = B/A = 2. 3. Hydrophytic Vegetation Indicators: 4. ☐ 1 – Rapid Test for Hydrophytic Vegetation 5. ☒ 2 – Dominance Test is > 50% 6. ☐ 3 – Prevalence Index is ≤ 3.01 7. ☐ 4 – Morphological Adaptations1 (Provide supportingdata in Remarks or on a separate sheet) 8. 9. ☐ 5 – Wetland Non-Vascular Plants1 10. ☐ Problematic Hydrophytic Vegetation1 (Explain) 11. 1Indicators of hydric soil and wetland hydrology must be present, unless disturbed or problematic. 0* = Total Cover Woody Vine Stratum (Plot size: 3-m diameter) Hydrophytic Vegetation Present? Yes ☒No ☐ 1. 2. 0 = Total Cover % Bare Ground in Herb Stratum: 0** Remarks: *Carex obnupta patch approx. 2 feet from soil pit. **Groundcover is 1-2 inches of dead leaves. WETLAND DETERMINATION DATA FORM – Western Mountains, Valleys, and Coast Region US Army Corps of Engineers Western Mountains, Valleys, and Coast – Version 2.0 SOIL Sampling Point: DP-15 HYDROLOGY Profile Description: (Describe to the depth needed to document the indicator or confirm the absence of indicators.) Depth Matrix Redox Features (inches) Color (moist) % Color (moist) % Type1 Loc2 Texture Remarks 0-5 10YR 2/1 100 Silt loam 5-10 10YR 2/2 95 7.5YR 4/6 5 C M Silt loam 10-16 10YR 3/2 95 7.5YR 4/6 5 C M Silt loam 16-20 2.5Y 7/1 97 7.5YR 4/6 3 C M Silt 1Type: C=Concentration, D=Depletion, RM=Reduced Matrix, CS=Covered or Coated Sand Grains. 2Loc: PL=Pore Lining, M=Matrix. Hydric Soil Indicators: (Applicable to all LRRs, unless otherwise noted.) Indicators for Problematic Hydric Soils3: ☐ Histosol (A1) ☐ Sandy Redox (S5) ☐ 2cm Muck (A10) ☐ Histic Epipedon (A2) ☐ Stripped Matrix (S6) ☐ Red Parent Material (TF2) ☐ Black Histic (A3) ☐ Loamy Mucky Mineral (F1) (except MLRA 1) ☐ Very Shallow Dark Surface (TF12) ☐ Hydrogen Sulfide (A4) ☐ Loamy Gleyed Matrix (F2) ☐ Other (Explain in Remarks) ☐ Depleted Below Dark Surface (A11) ☐ Depleted Matrix (F3) ☐ Thick Dark Surface (A12) ☒ Redox Dark Surface (F6) 3 Indicators of hydrophytic vegetation and wetland hydrology must be present, unless disturbed or problematic. ☐ Sandy Mucky Mineral (S1) ☐ Depleted Dark Surface (F7) ☐ Sandy Gleyed Matrix (S4) ☐ Redox Depressions (F8) Restrictive Layer (if present): Hydric soil present? Yes ☒No ☐Type: Depth (inches): Remarks: Wetland Hydrology Indicators: Primary Indicators (minimum of one required: check all that apply) Secondary Indicators (2 or more required) ☐ Surface water (A1) ☐ Water-Stained Leaves (except MLRA 1, 2, 4A& 4B) (B9) ☐ Water-Stained Leaves (B9) (MLRA 1,2, 4A & 4B) ☐ High Water Table (A2) ☐ Saturation (A3) ☐ Salt Crust (B11) ☐ Drainage Patterns (B10) ☐ Water Marks (B1) ☐ Aquatic Invertebrates (B13) ☐ Dry-Season Water Table (C2) ☐ Sediment Deposits (B2) ☐ Hydrogen Sulfide Odor (C1) ☐ Saturation Visible on Aerial Imagery (C9) ☐ Drift Deposits (B3) ☐ Oxidized Rhizospheres along Living Roots (C3) ☒ Geomorphic Position (D2) ☐ Algal Mat or Crust (B4) ☐ Presence of Reduced Iron (C4) ☐ Shallow Aquitard (D3) ☐ Iron Deposits (B5) ☐ Recent Iron Reduction in Tilled Soils (C6) ☒ FAC-Neutral Test (D5) ☐ Surface Soil Cracks (B6) ☐ Stunted or Stressed Plants (D1) (LRR A) ☐ Raised Ant Mounds (D6) (LRR A) ☐ Inundation Visible on Aerial Imagery (B7) ☐ Other (explain in remarks) ☐ Frost-Heave Hummocks ☐ Sparsely Vegetated Concave Surface (B8) Field Observations: Wetland Hydrology Present? Yes ☒No ☐ Surface Water Present? Yes ☐ No ☒ Depth (in): Water Table Present? Yes ☐ No ☒ Depth (in): Saturation Present? Yes ☐ No ☒ Depth (in): (includes capillary fringe) Describe Recorded Data (stream gauge, monitoring well, aerial photos, previous inspections), if available: Remarks: US Army Corps of Engineers Western Mountains, Valleys, and Coast – Version 2.0 DP-16 Project/Site: Chelan Ave NE, Renton, WA City/County: Renton, WA Sampling date: 9/27/19 Applicant/Owner: Calvin Gasaway State: WA Sampling Point: 16 Investigator(s): L. Dougherty, P. Heltzel Section, Township, Range: 10, 23N, 05E Landform (hillslope, terrace, etc): Hillslope Local relief (concave, convex, none): None Slope (%): 3 Subregion (LRR): A Lat: Long: Datum: Soil Map Unit Name: Alderwood gravelly sandy loam, 8 to 15 percent slopes NWI classification: None Are climatic / hydrologic conditions on the site typical for this time of year? ☐ Yes ☒ No (If no, explain in remarks.) Are Vegetation ☐, Soil ☐, or Hydrology ☐ significantly disturbed? Are “Normal Circumstances” present on the site? ☒ Yes ☐ No Are Vegetation ☐, Soil ☐, or Hydrology ☐ naturally problematic? (If needed, explain any answers in Remarks.) SUMMARY OF FINDINGS – Attach site map showing sampling point locations, transects, important features, etc. Hydrophytic Vegetation Present? Yes ☐ No ☒ Is the Sampled Area within a Wetland? Yes ☐No ☒Hydric Soils Present? Yes ☐ No ☒ Wetland Hydrology Present? Yes ☐ No ☒ Remarks: Wetland C out-pit, parcel no. 1023059107 Climatic conditions considered “wetter than normal” per WETS table methodology. VEGETATION – Use scientific names of plants. Tree Stratum (Plot size: 5-m diameter) Absolute % Cover Dominant Species? Indicator Status Dominance Test worksheet: Number of Dominant Species that are OBL, FACW, or FAC: 1 (A) 1. 2. Total Number of Dominant Species Across all Strata: 2 (B) 3. 4. Percent of Dominant Species that are OBL, FACW, or FAC: 50 (A/B) 0 = Total Cover Sapling/Shrub Stratum (Plot size: 3-m diameter) Prevalence Index worksheet: 1. Total % Cover of: Multiply by: 2. OBL species x 1 = 3. FACW species x 2 = 4. FAC species 85 x 3 = 255 5. FACU species 50 x 4 = 200 0 = Total Cover UPL species x 5 = Herb Stratum (Plot size: 1-m diameter) Column Totals: 135 (A) 455 (B) 1.Ranunculus repens 50 Y FAC Prevalence Index = B/A = 3.4 2.Taraxacum officinale 30 Y FACU 3.Trifolium repens 25 N FAC Hydrophytic Vegetation Indicators: 4.Hypochaeris radicata 20 N FACU ☐ 1 – Rapid Test for Hydrophytic Vegetation 5.Grass sp.10 N FAC* ☐ 2 – Dominance Test is > 50% 6. ☐ 3 – Prevalence Index is ≤ 3.01 7. ☐ 4 – Morphological Adaptations1 (Provide supportingdata in Remarks or on a separate sheet) 8. 9. ☐ 5 – Wetland Non-Vascular Plants1 10. ☐ Problematic Hydrophytic Vegetation1 (Explain) 11. 1Indicators of hydric soil and wetland hydrology must be present, unless disturbed or problematic. 135 = Total Cover Woody Vine Stratum (Plot size: 3-m diameter) Hydrophytic Vegetation Present? Yes ☐No ☒ 1. 2. 0 = Total Cover % Bare Ground in Herb Stratum: Remarks: *Presumed FAC indicator status WETLAND DETERMINATION DATA FORM – Western Mountains, Valleys, and Coast Region US Army Corps of Engineers Western Mountains, Valleys, and Coast – Version 2.0 SOIL Sampling Point: DP-16 HYDROLOGY Profile Description: (Describe to the depth needed to document the indicator or confirm the absence of indicators.) Depth Matrix Redox Features (inches) Color (moist) % Color (moist) % Type1 Loc2 Texture Remarks 0-4 10YR 3/2 100 Silt loam 4-16 7.5YR 2/5/2 99 7.5YR 4/6 1 C M Silt loam 1Type: C=Concentration, D=Depletion, RM=Reduced Matrix, CS=Covered or Coated Sand Grains. 2Loc: PL=Pore Lining, M=Matrix. Hydric Soil Indicators: (Applicable to all LRRs, unless otherwise noted.) Indicators for Problematic Hydric Soils3: ☐ Histosol (A1) ☐ Sandy Redox (S5) ☐ 2cm Muck (A10) ☐ Histic Epipedon (A2) ☐ Stripped Matrix (S6) ☐ Red Parent Material (TF2) ☐ Black Histic (A3) ☐ Loamy Mucky Mineral (F1) (except MLRA 1) ☐ Very Shallow Dark Surface (TF12) ☐ Hydrogen Sulfide (A4) ☐ Loamy Gleyed Matrix (F2) ☐ Other (Explain in Remarks) ☐ Depleted Below Dark Surface (A11) ☐ Depleted Matrix (F3) ☐ Thick Dark Surface (A12) ☐ Redox Dark Surface (F6) 3 Indicators of hydrophytic vegetation and wetland hydrology must be present, unless disturbed or problematic. ☐ Sandy Mucky Mineral (S1) ☐ Depleted Dark Surface (F7) ☐ Sandy Gleyed Matrix (S4) ☐ Redox Depressions (F8) Restrictive Layer (if present): Hydric soil present? Yes ☐No ☒Type: Depth (inches): Remarks: Wetland Hydrology Indicators: Primary Indicators (minimum of one required: check all that apply) Secondary Indicators (2 or more required) ☐ Surface water (A1) ☐ Water-Stained Leaves (except MLRA 1, 2, 4A& 4B) (B9) ☐ Water-Stained Leaves (B9) (MLRA 1,2, 4A & 4B) ☐ High Water Table (A2) ☐ Saturation (A3) ☐ Salt Crust (B11) ☐ Drainage Patterns (B10) ☐ Water Marks (B1) ☐ Aquatic Invertebrates (B13) ☐ Dry-Season Water Table (C2) ☐ Sediment Deposits (B2) ☐ Hydrogen Sulfide Odor (C1) ☐ Saturation Visible on Aerial Imagery (C9) ☐ Drift Deposits (B3) ☐ Oxidized Rhizospheres along Living Roots (C3) ☐ Geomorphic Position (D2) ☐ Algal Mat or Crust (B4) ☐ Presence of Reduced Iron (C4) ☐ Shallow Aquitard (D3) ☐ Iron Deposits (B5) ☐ Recent Iron Reduction in Tilled Soils (C6) ☐ FAC-Neutral Test (D5) ☐ Surface Soil Cracks (B6) ☐ Stunted or Stressed Plants (D1) (LRR A) ☐ Raised Ant Mounds (D6) (LRR A) ☐ Inundation Visible on Aerial Imagery (B7) ☐ Other (explain in remarks) ☐ Frost-Heave Hummocks ☐ Sparsely Vegetated Concave Surface (B8) Field Observations: Wetland Hydrology Present? Yes ☐No ☒ Surface Water Present? Yes ☐ No ☒ Depth (in): Water Table Present? Yes ☐ No ☒ Depth (in): Saturation Present? Yes ☐ No ☒ Depth (in): (includes capillary fringe) Describe Recorded Data (stream gauge, monitoring well, aerial photos, previous inspections), if available: Remarks: Wetland Rating System for Western WA: 2014 Update Rating Form – Effective January 1, 2015 1 Wetland name or number: Wetland B RATING SUMMARY – Western Washington Name of wetland (or ID #): Chelan Ave NE – Wetland B Date of site visit: September 20-21, 2018 Rated by: P. Heltzel, L. Dougherty Trained by Ecology? ☒Y ☐N Date of training: 10/2018 HGM Class used for rating: Depressional Wetland has multiple HGM classes? ☐Y ☒N NOTE: Form is not complete without the figures requested (figures can be combined). Source of base aerial photo/map: King County iMap / Google Earth OVERALL WETLAND CATEGORY (based on functions ☒ or special characteristics ☐) 1. Category of wetland based on FUNCTIONS ☐ Category I – Total score = 23 - 27 ☐ Category II – Total score = 20 - 22 ☐ Category III – Total score = 16 - 19 ☒ Category IV – Total score = 9 - 15 FUNCTION Improving Water Quality Hydrologic Habitat Circle the appropriate ratings Site Potential H M L H M L H M L Landscape Potential H M L H M L H M L Value H M L H M L H M L TOTAL Score Based on Ratings 6 5 4 15 2. Category based on SPECIAL CHARACTERISTICS of wetland CHARACTERISTIC CATEGORY Estuarine I II Wetland of High Conservation Value I Bog I Mature Forest I Old Growth Forest I Coastal Lagoon I II Interdunal I II III IV None of the above ☒ *Peter Heltzel and Logan Dougherty completed the UW Wetland Science and Management Certificate in May 2018. Score for each function based on three ratings (order of ratings is not important) 9 = H,H,H 8 = H,H,M 7 = H,H,L 7 = H,M,M 6 = H,M,L 6 = M,M,M 5 = H,L,L 5 = M,M,L 4 = M,L,L 3 = L,L,L Wetland Rating System for Western WA: 2014 Update Rating Form – Effective January 1, 2015 2 Wetland name or number: Wetland B Maps and figures required to answer questions correctly for Western Washington Depressional Wetlands Map of: To answer questions: Figure # Cowardin plant classes D 1.3, H 1.1, H 1.4 1 Hydroperiods D 1.4, H 1.2 2 Location of outlet (can be added to map of hydroperiods) D 1.1, D 4.1 2 Boundary of area within 150 ft of the wetland (can be added to another figure) D 2.2, D 5.2 2 Map of the contributing basin D 4.3, D 5.3 3 1 km Polygon: Area that extends 1 km from entire wetland edge - including polygons for accessible habitat and undisturbed habitat H 2.1, H 2.2, H 2.3 4a Screen capture of map of 303(d) listed waters in basin (from Ecology website) D 3.1, D 3.2 5 Screen capture of list of TMDLs for WRIA in which unit is found (from web) D 3.3 6 Wetland Rating System for Western WA: 2014 Update Rating Form – Effective January 1, 2015 3 Wetland name or number: Wetland B HGM Classification of Wetlands in Western Washington 1.Are the water levels in the entire unit usually controlled by tides except during floods? ☒NO – go to 2 ☐YES – the wetland class is Tidal Fringe – go to 1.1 1.1 Is the salinity of the water during periods of annual low flow below 0.5 ppt (parts per thousand)? NO – Saltwater Tidal Fringe (Estuarine) YES – Freshwater Tidal Fringe If your wetland can be classified as a Freshwater Tidal Fringe use the forms for Riverine wetlands. If it is Saltwater Tidal Fringe it is an Estuarine wetland and is not scored. This method cannot be used to score functions for estuarine wetlands. 2.The entire wetland unit is flat and precipitation is the only source (>90%) of water to it. Groundwater and surface water runoff are NOT sources of water to the unit. ☒NO – go to 3 ☐YES – The wetland class is Flats If your wetland can be classified as a Flats wetland, use the form for Depressional wetlands. 3.Does the entire wetland unit meet all of the following criteria? ☐The vegetated part of the wetland is on the shores of a body of permanent open water (without any plants on the surface at any time of the year) at least 20 ac (8 ha) in size; ☐At least 30% of the open water area is deeper than 6.6 ft (2 m). ☒NO – go to 4 ☐YES – The wetland class is Lake Fringe (Lacustrine Fringe) 4.Does the entire wetland unit meet all of the following criteria? ☐The wetland is on a slope (slope can be very gradual), ☐The water flows through the wetland in one direction (unidirectional) and usually comes from seeps. It may flow subsurface, as sheetflow, or in a swale without distinct banks, ☐The water leaves the wetland without being impounded. ☒NO – go to 5 ☐YES – The wetland class is Slope NOTE: Surface water does not pond in these type of wetlands except occasionally in very small and shallow depressions or behind hummocks (depressions are usually <3 ft diameter and less than 1 ft deep). 5.Does the entire wetland unit meet all of the following criteria? ☐The unit is in a valley, or stream channel, where it gets inundated by overbank flooding from that stream or river, ☐The overbank flooding occurs at least once every 2 years. For questions 1-7, the criteria described must apply to the entire unit being rated. If the hydrologic criteria listed in each question do not apply to the entire unit being rated, you probably have a unit with multiple HGM classes. In this case, identify which hydrologic criteria in questions 1-7 apply, and go to Question 8. Wetland Rating System for Western WA: 2014 Update Rating Form – Effective January 1, 2015 4 Wetland name or number: Wetland B ☒NO – go to 6 ☐YES – The wetland class is Riverine NOTE: The Riverine unit can contain depressions that are filled with water when the river is not flooding 6.Is the entire wetland unit in a topographic depression in which water ponds, or is saturated to the surface, at some time during the year? This means that any outlet, if present, is higher than the interior of the wetland. ☐NO – go to 7 ☒YES – The wetland class is Depressional 7.Is the entire wetland unit located in a very flat area with no obvious depression and no overbank flooding? The unit does not pond surface water more than a few inches. The unit seems to be maintained by high groundwater in the area. The wetland may be ditched, but has no obvious natural outlet. ☐NO – go to 8 ☐YES – The wetland class is Depressional 8.Your wetland unit seems to be difficult to classify and probably contains several different HGM classes. For example, seeps at the base of a slope may grade into a riverine floodplain, or a small stream within a Depressional wetland has a zone of flooding along its sides. GO BACK AND IDENTIFY WHICH OF THE HYDROLOGIC REGIMES DESCRIBED IN QUESTIONS 1-7 APPLY TO DIFFERENT AREAS IN THE UNIT (make a rough sketch to help you decide). Use the following table to identify the appropriate class to use for the rating system if you have several HGM classes present within the wetland unit being scored. NOTE: Use this table only if the class that is recommended in the second column represents 10% or more of the total area of the wetland unit being rated. If the area of the HGM class listed in column 2 is less than 10% of the unit; classify the wetland using the class that represents more than 90% of the total area. HGM classes within the wetland unit being rated HGM class to use in rating Slope + Riverine Riverine Slope + Depressional Depressional Slope + Lake Fringe Lake Fringe Depressional + Riverine along stream within boundary of depression Depressional Depressional + Lake Fringe Depressional Riverine + Lake Fringe Riverine Salt Water Tidal Fringe and any other class of freshwater wetland Treat as ESTUARINE If you are still unable to determine which of the above criteria apply to your wetland, or if you have more than 2 HGM classes within a wetland boundary, classify the wetland as Depressional for the rating. Wetland Rating System for Western WA: 2014 Update Rating Form – Effective January 1, 2015 5 Wetland name or number: Wetland B DEPRESSIONAL AND FLATS WETLANDS Water Quality Functions - Indicators that the site functions to improve water quality D 1.0. Does the site have the potential to improve water quality? D 1.1. Characteristics of surface water outflows from the wetland: ☐ Wetland is a depression or flat depression (QUESTION 7 on key) with no surface water leaving it (no outlet). points = 3 ☒ Wetland has an intermittently flowing stream or ditch, OR highly constricted permanently flowing outlet. points = 2 ☐ Wetland has an unconstricted, or slightly constricted, surface outlet that is permanently flowing. points = 1 ☐ Wetland is a flat depression (QUESTION 7 on key), whose outlet is a permanently flowing ditch. points = 1 2 D 1.2. The soil 2 in below the surface (or duff layer) is true clay or true organic (use NRCS definitions).☐Yes = 4 ☒No = 0 0 D 1.3. Characteristics and distribution of persistent plants (Emergent, Scrub-shrub, and/or Forested Cowardin classes): ☒ Wetland has persistent, ungrazed, plants > 95% of area points = 5 ☐ Wetland has persistent, ungrazed, plants > 1/2 of area points = 3 ☐ Wetland has persistent, ungrazed plants > 1/10 of area points = 1 ☐ Wetland has persistent, ungrazed plants < 1/10 of area points = 0 5 D 1.4. Characteristics of seasonal ponding or inundation: This is the area that is ponded for at least 2 months. See description in manual. ☐ Area seasonally ponded is > ½ total area of wetland points = 4 ☐ Area seasonally ponded is > ¼ total area of wetland points = 2 ☒ Area seasonally ponded is < ¼ total area of wetland points = 0 0 Total for D 1 Add the points in the boxes above 7 Rating of Site Potential If score is: ☐12-16 = H ☒6-11 = M ☐0-5 = L Record the rating on the first page D 2.0. Does the landscape have the potential to support the water quality function of the site? D 2.1. Does the wetland unit receive stormwater discharges? ☐Yes = 1 ☒No = 0 0 D 2.2. Is > 10% of the area within 150 ft of the wetland in land uses that generate pollutants? ☒Yes = 1 ☐No = 0 1 D 2.3. Are there septic systems within 250 ft of the wetland? ☒Yes = 1 ☐No = 0 1 D 2.4. Are there other sources of pollutants coming into the wetland that are not listed in questions D 2.1-D 2.3? Source: Click here to enter text. ☐Yes = 1 ☒No = 0 0 Total for D 2 Add the points in the boxes above 2 Rating of Landscape Potential If score is: ☐3 or 4 = H ☒1 or 2 = M ☐0 = L Record the rating on the first page D 3.0. Is the water quality improvement provided by the site valuable to society? D 3.1. Does the wetland discharge directly (i.e., within 1 mi) to a stream, river, lake, or marine water that is on the 303(d) list? ☐Yes = 1 ☒No = 0 0 D 3.2. Is the wetland in a basin or sub-basin where an aquatic resource is on the 303(d) list? ☒Yes = 1 ☐No = 0 1 D 3.3. Has the site been identified in a watershed or local plan as important for maintaining water quality (answer YES if there is a TMDL for the basin in which the unit is found)? ☐Yes = 2 ☒No = 0 0 Total for D 3 Add the points in the boxes above 1 Rating of Value If score is: ☐2-4 = H ☒1 = M ☐0 = L Record the rating on the first page Wetland Rating System for Western WA: 2014 Update Rating Form – Effective January 1, 2015 6 Wetland name or number: Wetland B DEPRESSIONAL AND FLATS WETLANDS Hydrologic Functions - Indicators that the site functions to reduce flooding and stream degradation D 4.0. Does the site have the potential to reduce flooding and erosion? D 4.1. Characteristics of surface water outflows from the wetland: ☐ Wetland is a depression or flat depression with no surface water leaving it (no outlet). points = 4 ☒ Wetland has an intermittently flowing stream or ditch, OR highly constricted permanently flowing outlet. points = 2 ☐ Wetland is a flat depression (QUESTION 7 on key), whose outlet is a permanently flowing ditch. points = 1 ☐ Wetland has an unconstricted, or slightly constricted, surface outlet that is permanently flowing. points = 0 2 D 4.2. Depth of storage during wet periods: Estimate the height of ponding above the bottom of the outlet. For wetlands with no outlet, measure from the surface of permanent water or if dry, the deepest part. ☐ Marks of ponding are 3 ft or more above the surface or bottom of outlet. points = 7 ☐ Marks of ponding between 2 ft to < 3 ft from surface or bottom of outlet. points = 5 ☐ Marks are at least 0.5 ft to < 2 ft from surface or bottom of outlet. points = 3 ☐ The wetland is a “headwater” wetland. points = 3 ☐ Wetland is flat but has small depressions on the surface that trap water. points = 1 ☒ Marks of ponding less than 0.5 ft (6 in). points = 0 0 D 4.3. Contribution of the wetland to storage in the watershed: Estimate the ratio of the area of upstream basin contributing surface water to the wetland to the area of the wetland unit itself. ☐ The area of the basin is less than 10 times the area of the unit. points = 5 ☒ The area of the basin is 10 to 100 times the area of the unit. points = 3 ☐ The area of the basin is more than 100 times the area of the unit. points = 0 ☐ Entire wetland is in the Flats class. points = 5 3 Total for D 4 Add the points in the boxes above 5 Rating of Site Potential If score is: ☐12-16 = H ☐6-11 = M ☒0-5 = L Record the rating on the first page D 5.0. Does the landscape have the potential to support hydrologic functions of the site? D 5.1. Does the wetland receive stormwater discharges? ☐Yes = 1 ☒No = 0 0 D 5.2. Is >10% of the area within 150 ft of the wetland in land uses that generate excess runoff? ☒Yes = 1 ☐No = 0 1 D 5.3. Is more than 25% of the contributing basin of the wetland covered with intensive human land uses (residential at >1 residence/ac, urban, commercial, agriculture, etc.)? ☒Yes = 1 ☐No = 0 1 Total for D 5 Add the points in the boxes above 2 Rating of Landscape Potential If score is: ☐3 = H ☒1 or 2 = M ☐0 = L Record the rating on the first page D 6.0. Are the hydrologic functions provided by the site valuable to society? D 6.1. The unit is in a landscape that has flooding problems. Choose the description that best matches conditions around the wetland unit being rated. Do not add points. Choose the highest score if more than one condition is met. The wetland captures surface water that would otherwise flow down-gradient into areas where flooding has damaged human or natural resources (e.g., houses or salmon redds): ☐ Flooding occurs in a sub-basin that is immediately down-gradient of unit.points = 2 ☒ Surface flooding problems are in a sub-basin farther down-gradient.points = 1 ☐ Flooding from groundwater is an issue in the sub-basin. points = 1 ☐ The existing or potential outflow from the wetland is so constrained by human or natural conditions that the water stored by the wetland cannot reach areas that flood. Explain why: …. points = 0 ☐There are no problems with flooding downstream of the wetland. points = 0 1 D 6.2. Has the site been identified as important for flood storage or flood conveyance in a regional flood control plan? ☐Yes = 2 ☒No = 0 0 Total for D 6 Add the points in the boxes above 1 Rating of Value If score is: ☐2-4 = H ☒1 = M ☐0 = L Record the rating on the first page Wetland name or number: Wetland B Wetland Rating System for Western WA: 2014 Update Rating Form – Effective January 1, 2015 7 These questions apply to wetlands of all HGM classes. HABITAT FUNCTIONS - Indicators that site functions to provide important habitat H 1.0. Does the site have the potential to provide habitat? H 1.1. Structure of plant community: Indicators are Cowardin classes and strata within the Forested class. Check the Cowardin plant classes in the wetland. Up to 10 patches may be combined for each class to meet the threshold of ¼ ac or more than 10% of the unit if it is smaller than 2.5 ac. Add the number of structures checked. ☐ Aquatic bed 4 structures or more: points = 4 ☐ Emergent 3 structures: points = 2 ☒ Scrub-shrub (areas where shrubs have > 30% cover) 2 structures: points = 1 ☒ Forested (areas where trees have > 30% cover) 1 structure: points = 0 If the unit has a Forested class, check if: ☐ The Forested class has 3 out of 5 strata (canopy, sub-canopy, shrubs, herbaceous, moss/ground-cover) that each cover 20% within the Forested polygon 1 H 1.2. Hydroperiods Check the types of water regimes (hydroperiods) present within the wetland. The water regime has to cover more than 10% of the wetland or ¼ ac to count (see text for descriptions of hydroperiods). ☐ Permanently flooded or inundated 4 or more types present: points = 3 ☐ Seasonally flooded or inundated 3 types present: points = 2 ☒ Occasionally flooded or inundated 2 types present: points = 1 ☒ Saturated only 1 type present: points = 0 ☐ Permanently flowing stream or river in, or adjacent to, the wetland ☐ Seasonally flowing stream in, or adjacent to, the wetland ☐ Lake Fringe wetland 2 points ☐ Freshwater tidal wetland 2 points 1 H 1.3. Richness of plant species Count the number of plant species in the wetland that cover at least 10 ft2. Different patches of the same species can be combined to meet the size threshold and you do not have to name the species. Do not include Eurasian milfoil, reed canarygrass, purple loosestrife, Canadian thistle If you counted: ☐ > 19 species points = 2 ☒ 5 - 19 species points = 1 ☐ < 5 species points = 0 1 H 1.4. Interspersion of habitats Decide from the diagrams below whether interspersion among Cowardin plants classes (described in H 1.1), or the classes and unvegetated areas (can include open water or mudflats) is high, moderate, low, or none. If you have four or more plant classes or three classes and open water, the rating is always high. ☐ None = 0 points ☒ Low = 1 point ☐ Moderate = 2 points All three diagrams in this row are ☐ HIGH = 3points 1 Wetland name or number: Wetland B Wetland Rating System for Western WA: 2014 Update Rating Form – Effective January 1, 2015 8 H 1.5. Special habitat features: Check the habitat features that are present in the wetland. The number of checks is the number of points. ☒ Large, downed, woody debris within the wetland (> 4 in diameter and 6 ft long). ☒ Standing snags (dbh > 4 in) within the wetland. ☐ Undercut banks are present for at least 6.6 ft (2 m) AND/OR overhanging plants extends at least 3.3 ft (1 m) over a stream (or ditch) in, or contiguous with the wetland, for at least 33 ft (10 m). ☐ Stable steep banks of fine material that might be used by beaver or muskrat for denning (> 30 degree slope) OR signs of recent beaver activity are present (cut shrubs or trees that have not yet weathered where wood is exposed). ☐ At least ¼ ac of thin-stemmed persistent plants or woody branches are present in areas that are permanently or seasonally inundated (structures for egg-laying by amphibians). ☐ Invasive plants cover less than 25% of the wetland area in every stratum of plants (see H 1.1 for list of strata). 2 Total for H 1 Add the points in the boxes above 6 Rating of Site Potential If score is: ☐15-18 = H ☐7-14 = M ☒0-6 = L Record the rating on the first page H 2.0. Does the landscape have the potential to support the habitat functions of the site? H 2.1. Accessible habitat (include only habitat that directly abuts wetland unit). Calculate: % undisturbed habitat + [(%moderate and low intensity land uses)/2] = 0% + (0.1%/2) = 0.05% If total accessible habitat is: ☐ > 1/3 (33.3%) of 1 km Polygon points = 3 ☐ 20-33% of 1 km Polygon points = 2 ☐ 10-19% of 1 km Polygon points = 1 ☒ < 10% of 1 km Polygon points = 0 0 H 2.2. Undisturbed habitat in 1 km Polygon around the wetland. Calculate: % undisturbed habitat + [(%moderate and low intensity land uses)/2 = 6.8% + (1.7%/2) = 7.65% ☐ Undisturbed habitat > 50% of Polygon points = 3 ☐ Undisturbed habitat 10-50% and in 1-3 patches points = 2 ☐ Undisturbed habitat 10-50% and > 3 patches points = 1 ☒ Undisturbed habitat < 10% of 1 km Polygon points = 0 0 H 2.3. Land use intensity in 1 km Polygon: If ☒ > 50% of 1 km Polygon is high intensity land use points = (- 2) ☐ ≤ 50% of 1 km Polygon is high intensity points = 0 -2 Total for H 2 Add the points in the boxes above -2 Rating of Landscape Potential If score is: ☐4-6 = H ☐1-3 = M ☒< 1 = L Record the rating on the first page H 3.0. Is the habitat provided by the site valuable to society? H 3.1. Does the site provide habitat for species valued in laws, regulations, or policies? Choose only the highest score that applies to the wetland being rated. Site meets ANY of the following criteria: points = 2 ☐ It has 3 or more priority habitats within 100 m (see next page) ☐ It provides habitat for Threatened or Endangered species (any plant or animal on the state or federal lists) ☐ It is mapped as a location for an individual WDFW priority species ☐ It is a Wetland of High Conservation Value as determined by the Department of Natural Resources ☐ It has been categorized as an important habitat site in a local or regional comprehensive plan, in a Shoreline Master Plan, or in a watershed plan ☒ Site has 1 or 2 priority habitats (listed on next page) within 100 m points = 1 ☐ Site does not meet any of the criteria above points = 0 1 Rating of Value If score is: ☐2 = H ☒1 = M ☐0 = L Record the rating on the first page Wetland name or number: Wetland B Wetland Rating System for Western WA: 2014 Update Rating Form – Effective January 1, 2015 9 WDFW Priority Habitats Priority habitats listed by WDFW (see complete descriptions of WDFW priority habitats, and the counties in which they can be found, in: Washington Department of Fish and Wildlife. 2008. Priority Habitat and Species List. Olympia, Washington. 177 pp. http://wdfw.wa.gov/publications/00165/wdfw00165.pdf or access the list from here: http://wdfw.wa.gov/conservation/phs/list/) Count how many of the following priority habitats are within 330 ft (100 m) of the wetland unit: NOTE: This question is independent of the land use between the wetland unit and the priority habitat. ☐ Aspen Stands: Pure or mixed stands of aspen greater than 1 ac (0.4 ha). ☐ Biodiversity Areas and Corridors: Areas of habitat that are relatively important to various species of native fish and wildlife (full descriptions in WDFW PHS report). ☐ Herbaceous Balds: Variable size patches of grass and forbs on shallow soils over bedrock. ☐ Old-growth/Mature forests: Old-growth west of Cascade crest – Stands of at least 2 tree species, forming a multi- layered canopy with occasional small openings; with at least 8 trees/ac (20 trees/ha ) > 32 in (81 cm) dbh or > 200 years of age. Mature forests – Stands with average diameters exceeding 21 in (53 cm) dbh; crown cover may be less than 100%; decay, decadence, numbers of snags, and quantity of large downed material is generally less than that found in old-growth; 80-200 years old west of the Cascade crest. ☐ Oregon White Oak: Woodland stands of pure oak or oak/conifer associations where canopy coverage of the oak component is important (full descriptions in WDFW PHS report p. 158 – see web link above). ☐ Riparian: The area adjacent to aquatic systems with flowing water that contains elements of both aquatic and terrestrial ecosystems which mutually influence each other. ☐ Westside Prairies: Herbaceous, non-forested plant communities that can either take the form of a dry prairie or a wet prairie (full descriptions in WDFW PHS report p. 161 – see web link above). ☐ Instream: The combination of physical, biological, and chemical processes and conditions that interact to provide functional life history requirements for instream fish and wildlife resources. ☐ Nearshore: Relatively undisturbed nearshore habitats. These include Coastal Nearshore, Open Coast Nearshore, and Puget Sound Nearshore. (full descriptions of habitats and the definition of relatively undisturbed are in WDFW report – see web link on previous page). ☐ Caves: A naturally occurring cavity, recess, void, or system of interconnected passages under the earth in soils, rock, ice, or other geological formations and is large enough to contain a human. ☐ Cliffs: Greater than 25 ft (7.6 m) high and occurring below 5000 ft elevation. ☐ Talus: Homogenous areas of rock rubble ranging in average size 0.5 - 6.5 ft (0.15 - 2.0 m), composed of basalt, andesite, and/or sedimentary rock, including riprap slides and mine tailings. May be associated with cliffs. ☒ Snags and Logs: Trees are considered snags if they are dead or dying and exhibit sufficient decay characteristics to enable cavity excavation/use by wildlife. Priority snags have a diameter at breast height of > 20 in (51 cm) in western Washington and are > 6.5 ft (2 m) in height. Priority logs are > 12 in (30 cm) in diameter at the largest end, and > 20 ft (6 m) long. Note: All vegetated wetlands are by definition a priority habitat but are not included in this list because they are addressed elsewhere. Wetland name or number: Wetland B Wetland Rating System for Western WA: 2014 Update Rating Form – Effective January 1, 2015 10 CATEGORIZATION BASED ON SPECIAL CHARACTERISTICS Wetland Type Check off any criteria that apply to the wetland. Circle the category when the appropriate criteria are met. Category SC 1.0. Estuarine wetlands Does the wetland meet the following criteria for Estuarine wetlands? ☐ The dominant water regime is tidal, ☐ Vegetated, and ☐ With a salinity greater than 0.5 ppt ☐Yes –Go to SC 1.1 ☒No= Not an estuarine wetland SC 1.1. Is the wetland within a National Wildlife Refuge, National Park, National Estuary Reserve, Natural Area Preserve, State Park or Educational, Environmental, or Scientific Reserve designated under WAC 332-30-151? ☐Yes = Category I ☐No - Go to SC 1.2 Cat. I SC 1.2. Is the wetland unit at least 1 ac in size and meets at least two of the following three conditions? ☐ The wetland is relatively undisturbed (has no diking, ditching, filling, cultivation, grazing, and has less than 10% cover of non-native plant species. (If non-native species are Spartina, see page 25) ☐ At least ¾ of the landward edge of the wetland has a 100 ft buffer of shrub, forest, or un-grazed or un- mowed grassland. ☐ The wetland has at least two of the following features: tidal channels, depressions with open water, or contiguous freshwater wetlands. ☐Yes = Category I ☐No= Category II Cat. I Cat. II SC 2.0. Wetlands of High Conservation Value (WHCV) SC 2.1. Has the WA Department of Natural Resources updated their website to include the list of Wetlands of High Conservation Value? ☒Yes – Go to SC 2.2 ☐No – Go to SC 2.3 SC 2.2. Is the wetland listed on the WDNR database as a Wetland of High Conservation Value? http://www.dnr.wa.gov/NHPwetlandviewer ☐Yes = Category I ☒No = Not a WHCV SC 2.3. Is the wetland in a Section/Township/Range that contains a Natural Heritage wetland? http://file.dnr.wa.gov/publications/amp_nh_wetlands_trs.pdf ☐Yes – Contact WNHP/WDNR and go to SC 2.4 ☐No = Not a WHCV SC 2.4. Has WDNR identified the wetland within the S/T/R as a Wetland of High Conservation Value and listed it on their website? ☐Yes = Category I ☐No = Not a WHCV Cat. I SC 3.0. Bogs Does the wetland (or any part of the unit) meet both the criteria for soils and vegetation in bogs? Use the key below. If you answer YES you will still need to rate the wetland based on its functions. SC 3.1. Does an area within the wetland unit have organic soil horizons, either peats or mucks, that compose 16 in or more of the first 32 in of the soil profile? ☐Yes – Go to SC 3.3 ☒No – Go to SC 3.2 SC 3.2. Does an area within the wetland unit have organic soils, either peats or mucks, that are less than 16 in deep over bedrock, or an impermeable hardpan such as clay or volcanic ash, or that are floating on top of a lake or pond? ☐Yes – Go to SC 3.3 ☒No = Is not a bog SC 3.3. Does an area with peats or mucks have more than 70% cover of mosses at ground level, AND at least a 30% cover of plant species listed in Table 4? ☐Yes = Is a Category I bog ☐No – Go to SC 3.4 NOTE: If you are uncertain about the extent of mosses in the understory, you may substitute that criterion by measuring the pH of the water that seeps into a hole dug at least 16 in deep. If the pH is less than 5.0 and the plant species in Table 4 are present, the wetland is a bog. SC 3.4. Is an area with peats or mucks forested (> 30% cover) with Sitka spruce, subalpine fir, western red cedar, western hemlock, lodgepole pine, quaking aspen, Engelmann spruce, or western white pine, AND any of the species (or combination of species) listed in Table 4 provide more than 30% of the cover under the canopy? ☐Yes = Is a Category I bog ☐No = Is not a bog Cat. I Wetland name or number: Wetland B Wetland Rating System for Western WA: 2014 Update Rating Form – Effective January 1, 2015 11 SC 4.0. Forested Wetlands Does the wetland have at least 1 contiguous acre of forest that meets one of these criteria for the WA Department of Fish and Wildlife’s forests as priority habitats? If you answer YES you will still need to rate the wetland based on its functions. ☐ Old-growth forests (west of Cascade crest): Stands of at least two tree species, forming a multi-layered canopy with occasional small openings; with at least 8 trees/ac (20 trees/ha) that are at least 200 years of age OR have a diameter at breast height (dbh) of 32 in (81 cm) or more. ☐ Mature forests (west of the Cascade Crest): Stands where the largest trees are 80- 200 years old OR the species that make up the canopy have an average diameter (dbh) exceeding 21 in (53 cm). ☐Yes = Category I ☒No = Not a forested wetland for this section Cat. I SC 5.0. Wetlands in Coastal Lagoons Does the wetland meet all of the following criteria of a wetland in a coastal lagoon? ☐ The wetland lies in a depression adjacent to marine waters that is wholly or partially separated from marine waters by sandbanks, gravel banks, shingle, or, less frequently, rocks ☐ The lagoon in which the wetland is located contains ponded water that is saline or brackish (> 0.5 ppt) during most of the year in at least a portion of the lagoon (needs to be measured near the bottom) ☐Yes – Go to SC 5.1 ☒No = Not a wetland in a coastal lagoon SC 5.1. Does the wetland meet all of the following three conditions? ☐ The wetland is relatively undisturbed (has no diking, ditching, filling, cultivation, grazing), and has less than 20% cover of aggressive, opportunistic plant species (see list of species on p. 100). ☐ At least ¾ of the landward edge of the wetland has a 100 ft buffer of shrub, forest, or un-grazed or un- mowed grassland. ☐ The wetland is larger than 1/10 ac (4350 ft2) ☐Yes = Category I ☐No = Category II Cat. I Cat. II SC 6.0. Interdunal Wetlands Is the wetland west of the 1889 line (also called the Western Boundary of Upland Ownership or WBUO)? If you answer yes you will still need to rate the wetland based on its habitat functions. In practical terms that means the following geographic areas: ☐ Long Beach Peninsula: Lands west of SR 103 ☐ Grayland-Westport: Lands west of SR 105 ☐ Ocean Shores-Copalis: Lands west of SR 115 and SR 109 ☐Yes – Go to SC 6.1 ☒No = not an interdunal wetland for rating SC 6.1. Is the wetland 1 ac or larger and scores an 8 or 9 for the habitat functions on the form (rates H,H,H or H,H,M for the three aspects of function)? ☐Yes = Category I ☐No – Go to SC 6.2 SC 6.2. Is the wetland 1 ac or larger, or is it in a mosaic of wetlands that is 1 ac or larger? ☐Yes = Category II ☐No – Go to SC 6.3 SC 6.3. Is the unit between 0.1 and 1 ac, or is it in a mosaic of wetlands that is between 0.1 and 1 ac? ☐Yes = Category III ☐No = Category IV Cat I Cat. II Cat. III Cat. IV Category of wetland based on Special Characteristics If you answered No for all types, enter “Not Applicable” on Summary Form NA Wetland Rating System for Western WA: 2014 Update Rating Form – Effective January 1, 2015 12 Wetland name or number: Wetland B This page left blank intentionally Wetland Rating System for Western WA: 2014 Update Rating Form – Effective January 1, 2015 1 Wetland name or number: Wetland C RATING SUMMARY – Western Washington Name of wetland (or ID #): Chelan Ave NE – Wetland C Date of site visit: September 20-21, 2018 Rated by: P. Heltzel, L. Dougherty Trained by Ecology? ☒Y ☐N Date of training: 10/2018 HGM Class used for rating: Depressional Wetland has multiple HGM classes? ☐Y ☒N NOTE: Form is not complete without the figures requested (figures can be combined). Source of base aerial photo/map: King County iMap / Google Earth OVERALL WETLAND CATEGORY (based on functions ☒ or special characteristics ☐) 1.Category of wetland based on FUNCTIONS ☐ Category I – Total score = 23 - 27 ☐ Category II – Total score = 20 - 22 ☒ Category III – Total score = 16 - 19 ☐ Category IV – Total score = 9 - 15 FUNCTION Improving Water Quality Hydrologic Habitat Circle the appropriate ratings Site Potential H M L H M L H M L Landscape Potential H M L H M L H M L Value H M L H M L H M L TOTAL Score Based on Ratings 7 7 5 19 2.Category based on SPECIAL CHARACTERISTICS of wetland CHARACTERISTIC CATEGORY Estuarine I II Wetland of High Conservation Value I Bog I Mature Forest I Old Growth Forest I Coastal Lagoon I II Interdunal I II III IV None of the above ☒ Peter Heltzel and Logan Dougherty completed the UW Wetland Science and Management Certificate in May 2018. Score for each function based on three ratings (order of ratings is not important) 9 = H,H,H 8 = H,H,M 7 = H,H,L 7 = H,M,M 6 = H,M,L 6 = M,M,M 5 = H,L,L 5 = M,M,L 4 = M,L,L 3 = L,L,L Wetland Rating System for Western WA: 2014 Update Rating Form – Effective January 1, 2015 2 Wetland name or number: Wetland C Maps and figures required to answer questions correctly for Western Washington Depressional Wetlands Map of: To answer questions: Figure # Cowardin plant classes D 1.3, H 1.1, H 1.4 1 Hydroperiods D 1.4, H 1.2 2 Location of outlet (can be added to map of hydroperiods) D 1.1, D 4.1 2 Boundary of area within 150 ft of the wetland (can be added to another figure) D 2.2, D 5.2 2 Map of the contributing basin D 4.3, D 5.3 3 1 km Polygon: Area that extends 1 km from entire wetland edge - including polygons for accessible habitat and undisturbed habitat H 2.1, H 2.2, H 2.3 4b Screen capture of map of 303(d) listed waters in basin (from Ecology website) D 3.1, D 3.2 5 Screen capture of list of TMDLs for WRIA in which unit is found (from web) D 3.3 6 Wetland Rating System for Western WA: 2014 Update Rating Form – Effective January 1, 2015 3 Wetland name or number: Wetland C HGM Classification of Wetlands in Western Washington 1.Are the water levels in the entire unit usually controlled by tides except during floods? ☒NO – go to 2 ☐YES – the wetland class is Tidal Fringe – go to 1.1 1.1 Is the salinity of the water during periods of annual low flow below 0.5 ppt (parts per thousand)? NO – Saltwater Tidal Fringe (Estuarine) YES – Freshwater Tidal Fringe If your wetland can be classified as a Freshwater Tidal Fringe use the forms for Riverine wetlands. If it is Saltwater Tidal Fringe it is an Estuarine wetland and is not scored. This method cannot be used to score functions for estuarine wetlands. 2.The entire wetland unit is flat and precipitation is the only source (>90%) of water to it. Groundwater and surface water runoff are NOT sources of water to the unit. ☒NO – go to 3 ☐YES – The wetland class is Flats If your wetland can be classified as a Flats wetland, use the form for Depressional wetlands. 3.Does the entire wetland unit meet all of the following criteria? ☐The vegetated part of the wetland is on the shores of a body of permanent open water (without any plants on the surface at any time of the year) at least 20 ac (8 ha) in size; ☐At least 30% of the open water area is deeper than 6.6 ft (2 m). ☒NO – go to 4 ☐YES – The wetland class is Lake Fringe (Lacustrine Fringe) 4.Does the entire wetland unit meet all of the following criteria? ☐The wetland is on a slope (slope can be very gradual), ☐The water flows through the wetland in one direction (unidirectional) and usually comes from seeps. It may flow subsurface, as sheetflow, or in a swale without distinct banks, ☐The water leaves the wetland without being impounded. ☒NO – go to 5 ☐YES – The wetland class is Slope NOTE: Surface water does not pond in these type of wetlands except occasionally in very small and shallow depressions or behind hummocks (depressions are usually <3 ft diameter and less than 1 ft deep). 5.Does the entire wetland unit meet all of the following criteria? ☐The unit is in a valley, or stream channel, where it gets inundated by overbank flooding from that stream or river, ☐The overbank flooding occurs at least once every 2 years. For questions 1-7, the criteria described must apply to the entire unit being rated. If the hydrologic criteria listed in each question do not apply to the entire unit being rated, you probably have a unit with multiple HGM classes. In this case, identify which hydrologic criteria in questions 1-7 apply, and go to Question 8. Wetland Rating System for Western WA: 2014 Update Rating Form – Effective January 1, 2015 4 Wetland name or number: Wetland C ☒NO – go to 6 ☐YES – The wetland class is Riverine NOTE: The Riverine unit can contain depressions that are filled with water when the river is not flooding 6.Is the entire wetland unit in a topographic depression in which water ponds, or is saturated to the surface, at some time during the year? This means that any outlet, if present, is higher than the interior of the wetland. ☐NO – go to 7 ☒YES – The wetland class is Depressional 7.Is the entire wetland unit located in a very flat area with no obvious depression and no overbank flooding? The unit does not pond surface water more than a few inches. The unit seems to be maintained by high groundwater in the area. The wetland may be ditched, but has no obvious natural outlet. ☐NO – go to 8 ☐YES – The wetland class is Depressional 8.Your wetland unit seems to be difficult to classify and probably contains several different HGM classes. For example, seeps at the base of a slope may grade into a riverine floodplain, or a small stream within a Depressional wetland has a zone of flooding along its sides. GO BACK AND IDENTIFY WHICH OF THE HYDROLOGIC REGIMES DESCRIBED IN QUESTIONS 1-7 APPLY TO DIFFERENT AREAS IN THE UNIT (make a rough sketch to help you decide). Use the following table to identify the appropriate class to use for the rating system if you have several HGM classes present within the wetland unit being scored. NOTE: Use this table only if the class that is recommended in the second column represents 10% or more of the total area of the wetland unit being rated. If the area of the HGM class listed in column 2 is less than 10% of the unit; classify the wetland using the class that represents more than 90% of the total area. HGM classes within the wetland unit being rated HGM class to use in rating Slope + Riverine Riverine Slope + Depressional Depressional Slope + Lake Fringe Lake Fringe Depressional + Riverine along stream within boundary of depression Depressional Depressional + Lake Fringe Depressional Riverine + Lake Fringe Riverine Salt Water Tidal Fringe and any other class of freshwater wetland Treat as ESTUARINE If you are still unable to determine which of the above criteria apply to your wetland, or if you have more than 2 HGM classes within a wetland boundary, classify the wetland as Depressional for the rating. Wetland Rating System for Western WA: 2014 Update Rating Form – Effective January 1, 2015 5 Wetland name or number: Wetland C DEPRESSIONAL AND FLATS WETLANDS Water Quality Functions - Indicators that the site functions to improve water quality D 1.0. Does the site have the potential to improve water quality? D 1.1. Characteristics of surface water outflows from the wetland: ☐ Wetland is a depression or flat depression (QUESTION 7 on key) with no surface water leaving it (no outlet). points = 3 ☒ Wetland has an intermittently flowing stream or ditch, OR highly constricted permanently flowing outlet. points = 2 ☐ Wetland has an unconstricted, or slightly constricted, surface outlet that is permanently flowing. points = 1 ☐ Wetland is a flat depression (QUESTION 7 on key), whose outlet is a permanently flowing ditch. points = 1 2 D 1.2. The soil 2 in below the surface (or duff layer) is true clay or true organic (use NRCS definitions).☐Yes = 4 ☒No = 0 0 D 1.3. Characteristics and distribution of persistent plants (Emergent, Scrub-shrub, and/or Forested Cowardin classes): ☒ Wetland has persistent, ungrazed, plants > 95% of area points = 5 ☐ Wetland has persistent, ungrazed, plants > 1/2 of area points = 3 ☐ Wetland has persistent, ungrazed plants > 1/10 of area points = 1 ☐ Wetland has persistent, ungrazed plants < 1/10 of area points = 0 5 D 1.4. Characteristics of seasonal ponding or inundation: This is the area that is ponded for at least 2 months. See description in manual. ☐ Area seasonally ponded is > ½ total area of wetland points = 4 ☒ Area seasonally ponded is > ¼ total area of wetland points = 2 ☐ Area seasonally ponded is < ¼ total area of wetland points = 0 2 Total for D 1 Add the points in the boxes above 9 Rating of Site Potential If score is: ☐12-16 = H ☒6-11 = M ☐0-5 = L Record the rating on the first page D 2.0. Does the landscape have the potential to support the water quality function of the site? D 2.1. Does the wetland unit receive stormwater discharges? ☒Yes = 1 ☐No = 0 1 D 2.2. Is > 10% of the area within 150 ft of the wetland in land uses that generate pollutants? ☒Yes = 1 ☐No = 0 1 D 2.3. Are there septic systems within 250 ft of the wetland? ☒Yes = 1 ☐No = 0 1 D 2.4. Are there other sources of pollutants coming into the wetland that are not listed in questions D 2.1-D 2.3? Source: Click here to enter text. ☐Yes = 1 ☒No = 0 0 Total for D 2 Add the points in the boxes above 3 Rating of Landscape Potential If score is: ☒3 or 4 = H ☐1 or 2 = M ☐0 = L Record the rating on the first page D 3.0. Is the water quality improvement provided by the site valuable to society? D 3.1. Does the wetland discharge directly (i.e., within 1 mi) to a stream, river, lake, or marine water that is on the 303(d) list? ☐Yes = 1 ☒No = 0 0 D 3.2. Is the wetland in a basin or sub-basin where an aquatic resource is on the 303(d) list? ☒Yes = 1 ☐No = 0 1 D 3.3. Has the site been identified in a watershed or local plan as important for maintaining water quality (answer YES if there is a TMDL for the basin in which the unit is found)? ☐Yes = 2 ☒No = 0 0 Total for D 3 Add the points in the boxes above 1 Rating of Value If score is: ☐2-4 = H ☒1 = M ☐0 = L Record the rating on the first page Wetland Rating System for Western WA: 2014 Update Rating Form – Effective January 1, 2015 6 Wetland name or number: Wetland C DEPRESSIONAL AND FLATS WETLANDS Hydrologic Functions - Indicators that the site functions to reduce flooding and stream degradation D 4.0. Does the site have the potential to reduce flooding and erosion? D 4.1. Characteristics of surface water outflows from the wetland: ☐ Wetland is a depression or flat depression with no surface water leaving it (no outlet). points = 4 ☒ Wetland has an intermittently flowing stream or ditch, OR highly constricted permanently flowing outlet. points = 2 ☐ Wetland is a flat depression (QUESTION 7 on key), whose outlet is a permanently flowing ditch. points = 1 ☐ Wetland has an unconstricted, or slightly constricted, surface outlet that is permanently flowing. points = 0 2 D 4.2. Depth of storage during wet periods: Estimate the height of ponding above the bottom of the outlet. For wetlands with no outlet, measure from the surface of permanent water or if dry, the deepest part. ☐ Marks of ponding are 3 ft or more above the surface or bottom of outlet. points = 7 ☐ Marks of ponding between 2 ft to < 3 ft from surface or bottom of outlet. points = 5 ☒ Marks are at least 0.5 ft to < 2 ft from surface or bottom of outlet. points = 3 ☐ The wetland is a “headwater” wetland. points = 3 ☐ Wetland is flat but has small depressions on the surface that trap water. points = 1 ☐ Marks of ponding less than 0.5 ft (6 in). points = 0 3 D 4.3. Contribution of the wetland to storage in the watershed: Estimate the ratio of the area of upstream basin contributing surface water to the wetland to the area of the wetland unit itself. ☐ The area of the basin is less than 10 times the area of the unit. points = 5 ☒ The area of the basin is 10 to 100 times the area of the unit. points = 3 ☐ The area of the basin is more than 100 times the area of the unit. points = 0 ☐ Entire wetland is in the Flats class. points = 5 3 Total for D 4 Add the points in the boxes above 8 Rating of Site Potential If score is: ☐12-16 = H ☒6-11 = M ☐0-5 = L Record the rating on the first page D 5.0. Does the landscape have the potential to support hydrologic functions of the site? D 5.1. Does the wetland receive stormwater discharges? ☒Yes = 1 ☐No = 0 1 D 5.2. Is >10% of the area within 150 ft of the wetland in land uses that generate excess runoff? ☒Yes = 1 ☐No = 0 1 D 5.3. Is more than 25% of the contributing basin of the wetland covered with intensive human land uses (residential at >1 residence/ac, urban, commercial, agriculture, etc.)? ☒Yes = 1 ☐No = 0 1 Total for D 5 Add the points in the boxes above 3 Rating of Landscape Potential If score is: ☒3 = H ☐1 or 2 = M ☐0 = L Record the rating on the first page D 6.0. Are the hydrologic functions provided by the site valuable to society? D 6.1. The unit is in a landscape that has flooding problems. Choose the description that best matches conditions around the wetland unit being rated. Do not add points. Choose the highest score if more than one condition is met. The wetland captures surface water that would otherwise flow down-gradient into areas where flooding has damaged human or natural resources (e.g., houses or salmon redds): •☐ Flooding occurs in a sub-basin that is immediately down-gradient of unit.points = 2 •☒ Surface flooding problems are in a sub-basin farther down-gradient.points = 1 ☐ Flooding from groundwater is an issue in the sub-basin. points = 1 ☐ The existing or potential outflow from the wetland is so constrained by human or natural conditions that the water stored by the wetland cannot reach areas that flood. Explain why: …. points = 0 ☐There are no problems with flooding downstream of the wetland. points = 0 1 D 6.2. Has the site been identified as important for flood storage or flood conveyance in a regional flood control plan? ☐Yes = 2 ☒No = 0 0 Total for D 6 Add the points in the boxes above 1 Rating of Value If score is: ☐2-4 = H ☒1 = M ☐0 = L Record the rating on the first page Wetland name or number: Wetland C Wetland Rating System for Western WA: 2014 Update Rating Form – Effective January 1, 2015 7 These questions apply to wetlands of all HGM classes. HABITAT FUNCTIONS - Indicators that site functions to provide important habitat H 1.0. Does the site have the potential to provide habitat? H 1.1. Structure of plant community: Indicators are Cowardin classes and strata within the Forested class. Check the Cowardin plant classes in the wetland. Up to 10 patches may be combined for each class to meet the threshold of ¼ ac or more than 10% of the unit if it is smaller than 2.5 ac. Add the number of structures checked. ☐ Aquatic bed 4 structures or more: points = 4 ☐ Emergent 3 structures: points = 2 ☐ Scrub-shrub (areas where shrubs have > 30% cover) 2 structures: points = 1 ☒ Forested (areas where trees have > 30% cover) 1 structure: points = 0 If the unit has a Forested class, check if: ☒ The Forested class has 3 out of 5 strata (canopy, sub-canopy, shrubs, herbaceous, moss/ground-cover) that each cover 20% within the Forested polygon 1 H 1.2. Hydroperiods Check the types of water regimes (hydroperiods) present within the wetland. The water regime has to cover more than 10% of the wetland or ¼ ac to count (see text for descriptions of hydroperiods). ☐ Permanently flooded or inundated 4 or more types present: points = 3 ☒ Seasonally flooded or inundated 3 types present: points = 2 ☒ Occasionally flooded or inundated 2 types present: points = 1 ☐ Saturated only 1 type present: points = 0 ☐ Permanently flowing stream or river in, or adjacent to, the wetland ☐ Seasonally flowing stream in, or adjacent to, the wetland ☐ Lake Fringe wetland 2 points ☐ Freshwater tidal wetland 2 points 1 H 1.3. Richness of plant species Count the number of plant species in the wetland that cover at least 10 ft2. Different patches of the same species can be combined to meet the size threshold and you do not have to name the species. Do not include Eurasian milfoil, reed canarygrass, purple loosestrife, Canadian thistle If you counted: ☒ > 19 species points = 2 ☐ 5 - 19 species points = 1 ☐ < 5 species points = 0 2 H 1.4. Interspersion of habitats Decide from the diagrams below whether interspersion among Cowardin plants classes (described in H 1.1), or the classes and unvegetated areas (can include open water or mudflats) is high, moderate, low, or none. If you have four or more plant classes or three classes and open water, the rating is always high. ☒ None = 0 points ☐ Low = 1 point ☐ Moderate = 2 points All three diagrams in this row are ☐ HIGH = 3points 1 Wetland name or number: Wetland C Wetland Rating System for Western WA: 2014 Update Rating Form – Effective January 1, 2015 8 H 1.5. Special habitat features: Check the habitat features that are present in the wetland. The number of checks is the number of points. ☒ Large, downed, woody debris within the wetland (> 4 in diameter and 6 ft long). ☒ Standing snags (dbh > 4 in) within the wetland. ☐ Undercut banks are present for at least 6.6 ft (2 m) AND/OR overhanging plants extends at least 3.3 ft (1 m) over a stream (or ditch) in, or contiguous with the wetland, for at least 33 ft (10 m). ☐ Stable steep banks of fine material that might be used by beaver or muskrat for denning (> 30 degree slope) OR signs of recent beaver activity are present (cut shrubs or trees that have not yet weathered where wood is exposed). ☐ At least ¼ ac of thin-stemmed persistent plants or woody branches are present in areas that are permanently or seasonally inundated (structures for egg-laying by amphibians). ☒ Invasive plants cover less than 25% of the wetland area in every stratum of plants (see H 1.1 for list of strata). 3 Total for H 1 Add the points in the boxes above 8 Rating of Site Potential If score is: ☐15-18 = H ☒7-14 = M ☐0-6 = L Record the rating on the first page H 2.0. Does the landscape have the potential to support the habitat functions of the site? H 2.1. Accessible habitat (include only habitat that directly abuts wetland unit). Calculate: % undisturbed habitat + [(%moderate and low intensity land uses)/2] = 0% + (0.8%/2) = 0.4% If total accessible habitat is: ☐ > 1/3 (33.3%) of 1 km Polygon points = 3 ☐ 20-33% of 1 km Polygon points = 2 ☐ 10-19% of 1 km Polygon points = 1 ☒ < 10% of 1 km Polygon points = 0 0 H 2.2. Undisturbed habitat in 1 km Polygon around the wetland. Calculate: % undisturbed habitat + [(%moderate and low intensity land uses)/2 = 6.1% + (1.6%/2) = 6.9% ☐ Undisturbed habitat > 50% of Polygon points = 3 ☐ Undisturbed habitat 10-50% and in 1-3 patches points = 2 ☐ Undisturbed habitat 10-50% and > 3 patches points = 1 ☒ Undisturbed habitat < 10% of 1 km Polygon points = 0 0 H 2.3. Land use intensity in 1 km Polygon: If ☒ > 50% of 1 km Polygon is high intensity land use points = (- 2) ☐ ≤ 50% of 1 km Polygon is high intensity points = 0 -2 Total for H 2 Add the points in the boxes above -2 Rating of Landscape Potential If score is: ☐4-6 = H ☐1-3 = M ☒< 1 = L Record the rating on the first page H 3.0. Is the habitat provided by the site valuable to society? H 3.1. Does the site provide habitat for species valued in laws, regulations, or policies? Choose only the highest score that applies to the wetland being rated. Site meets ANY of the following criteria: points = 2 ☐ It has 3 or more priority habitats within 100 m (see next page) ☐ It provides habitat for Threatened or Endangered species (any plant or animal on the state or federal lists) ☐ It is mapped as a location for an individual WDFW priority species ☐ It is a Wetland of High Conservation Value as determined by the Department of Natural Resources ☐ It has been categorized as an important habitat site in a local or regional comprehensive plan, in a Shoreline Master Plan, or in a watershed plan ☒ Site has 1 or 2 priority habitats (listed on next page) within 100 m points = 1 ☐ Site does not meet any of the criteria above points = 0 1 Rating of Value If score is: ☐2 = H ☒1 = M ☐0 = L Record the rating on the first page Wetland name or number: Wetland C Wetland Rating System for Western WA: 2014 Update Rating Form – Effective January 1, 2015 9 WDFW Priority Habitats Priority habitats listed by WDFW (see complete descriptions of WDFW priority habitats, and the counties in which they can be found, in: Washington Department of Fish and Wildlife. 2008. Priority Habitat and Species List. Olympia, Washington. 177 pp. http://wdfw.wa.gov/publications/00165/wdfw00165.pdf or access the list from here: http://wdfw.wa.gov/conservation/phs/list/) Count how many of the following priority habitats are within 330 ft (100 m) of the wetland unit: NOTE: This question is independent of the land use between the wetland unit and the priority habitat. ☐ Aspen Stands: Pure or mixed stands of aspen greater than 1 ac (0.4 ha). ☐ Biodiversity Areas and Corridors: Areas of habitat that are relatively important to various species of native fish and wildlife (full descriptions in WDFW PHS report). ☐ Herbaceous Balds: Variable size patches of grass and forbs on shallow soils over bedrock. ☐ Old-growth/Mature forests: Old-growth west of Cascade crest – Stands of at least 2 tree species, forming a multi- layered canopy with occasional small openings; with at least 8 trees/ac (20 trees/ha ) > 32 in (81 cm) dbh or > 200 years of age. Mature forests – Stands with average diameters exceeding 21 in (53 cm) dbh; crown cover may be less than 100%; decay, decadence, numbers of snags, and quantity of large downed material is generally less than that found in old-growth; 80-200 years old west of the Cascade crest. ☐ Oregon White Oak: Woodland stands of pure oak or oak/conifer associations where canopy coverage of the oak component is important (full descriptions in WDFW PHS report p. 158 – see web link above). ☐ Riparian: The area adjacent to aquatic systems with flowing water that contains elements of both aquatic and terrestrial ecosystems which mutually influence each other. ☐ Westside Prairies: Herbaceous, non-forested plant communities that can either take the form of a dry prairie or a wet prairie (full descriptions in WDFW PHS report p. 161 – see web link above). ☐ Instream: The combination of physical, biological, and chemical processes and conditions that interact to provide functional life history requirements for instream fish and wildlife resources. ☐ Nearshore: Relatively undisturbed nearshore habitats. These include Coastal Nearshore, Open Coast Nearshore, and Puget Sound Nearshore. (full descriptions of habitats and the definition of relatively undisturbed are in WDFW report – see web link on previous page). ☐ Caves: A naturally occurring cavity, recess, void, or system of interconnected passages under the earth in soils, rock, ice, or other geological formations and is large enough to contain a human. ☐ Cliffs: Greater than 25 ft (7.6 m) high and occurring below 5000 ft elevation. ☐ Talus: Homogenous areas of rock rubble ranging in average size 0.5 - 6.5 ft (0.15 - 2.0 m), composed of basalt, andesite, and/or sedimentary rock, including riprap slides and mine tailings. May be associated with cliffs. ☒ Snags and Logs: Trees are considered snags if they are dead or dying and exhibit sufficient decay characteristics to enable cavity excavation/use by wildlife. Priority snags have a diameter at breast height of > 20 in (51 cm) in western Washington and are > 6.5 ft (2 m) in height. Priority logs are > 12 in (30 cm) in diameter at the largest end, and > 20 ft (6 m) long. Note: All vegetated wetlands are by definition a priority habitat but are not included in this list because they are addressed elsewhere. Wetland name or number: Wetland c Wetland Rating System for Western WA: 2014 Update Rating Form – Effective January 1, 2015 10 CATEGORIZATION BASED ON SPECIAL CHARACTERISTICS Wetland Type Check off any criteria that apply to the wetland. Circle the category when the appropriate criteria are met. Category SC 1.0. Estuarine wetlands Does the wetland meet the following criteria for Estuarine wetlands? ☐ The dominant water regime is tidal, ☐ Vegetated, and ☐ With a salinity greater than 0.5 ppt ☐Yes –Go to SC 1.1 ☒No= Not an estuarine wetland SC 1.1. Is the wetland within a National Wildlife Refuge, National Park, National Estuary Reserve, Natural Area Preserve, State Park or Educational, Environmental, or Scientific Reserve designated under WAC 332-30-151? ☐Yes = Category I ☐No - Go to SC 1.2 Cat. I SC 1.2. Is the wetland unit at least 1 ac in size and meets at least two of the following three conditions? ☐ The wetland is relatively undisturbed (has no diking, ditching, filling, cultivation, grazing, and has less than 10% cover of non-native plant species. (If non-native species are Spartina, see page 25) ☐ At least ¾ of the landward edge of the wetland has a 100 ft buffer of shrub, forest, or un-grazed or un- mowed grassland. ☐ The wetland has at least two of the following features: tidal channels, depressions with open water, or contiguous freshwater wetlands. ☐Yes = Category I ☐No= Category II Cat. I Cat. II SC 2.0. Wetlands of High Conservation Value (WHCV) SC 2.1. Has the WA Department of Natural Resources updated their website to include the list of Wetlands of High Conservation Value? ☒Yes – Go to SC 2.2 ☐No – Go to SC 2.3 SC 2.2. Is the wetland listed on the WDNR database as a Wetland of High Conservation Value? http://www.dnr.wa.gov/NHPwetlandviewer ☐Yes = Category I ☒No = Not a WHCV SC 2.3. Is the wetland in a Section/Township/Range that contains a Natural Heritage wetland? http://file.dnr.wa.gov/publications/amp_nh_wetlands_trs.pdf ☐Yes – Contact WNHP/WDNR and go to SC 2.4 ☐No = Not a WHCV SC 2.4. Has WDNR identified the wetland within the S/T/R as a Wetland of High Conservation Value and listed it on their website? ☐Yes = Category I ☐No = Not a WHCV Cat. I SC 3.0. Bogs Does the wetland (or any part of the unit) meet both the criteria for soils and vegetation in bogs? Use the key below. If you answer YES you will still need to rate the wetland based on its functions. SC 3.1. Does an area within the wetland unit have organic soil horizons, either peats or mucks, that compose 16 in or more of the first 32 in of the soil profile? ☐Yes – Go to SC 3.3 ☒No – Go to SC 3.2 SC 3.2. Does an area within the wetland unit have organic soils, either peats or mucks, that are less than 16 in deep over bedrock, or an impermeable hardpan such as clay or volcanic ash, or that are floating on top of a lake or pond? ☐Yes – Go to SC 3.3 ☒No = Is not a bog SC 3.3. Does an area with peats or mucks have more than 70% cover of mosses at ground level, AND at least a 30% cover of plant species listed in Table 4? ☐Yes = Is a Category I bog ☐No – Go to SC 3.4 NOTE: If you are uncertain about the extent of mosses in the understory, you may substitute that criterion by measuring the pH of the water that seeps into a hole dug at least 16 in deep. If the pH is less than 5.0 and the plant species in Table 4 are present, the wetland is a bog. SC 3.4. Is an area with peats or mucks forested (> 30% cover) with Sitka spruce, subalpine fir, western red cedar, western hemlock, lodgepole pine, quaking aspen, Engelmann spruce, or western white pine, AND any of the species (or combination of species) listed in Table 4 provide more than 30% of the cover under the canopy? ☐Yes = Is a Category I bog ☐No = Is not a bog Cat. I Wetland name or number: Wetland C Wetland Rating System for Western WA: 2014 Update Rating Form – Effective January 1, 2015 11 SC 4.0. Forested Wetlands Does the wetland have at least 1 contiguous acre of forest that meets one of these criteria for the WA Department of Fish and Wildlife’s forests as priority habitats? If you answer YES you will still need to rate the wetland based on its functions. ☐ Old-growth forests (west of Cascade crest): Stands of at least two tree species, forming a multi-layered canopy with occasional small openings; with at least 8 trees/ac (20 trees/ha) that are at least 200 years of age OR have a diameter at breast height (dbh) of 32 in (81 cm) or more. ☐ Mature forests (west of the Cascade Crest): Stands where the largest trees are 80- 200 years old OR the species that make up the canopy have an average diameter (dbh) exceeding 21 in (53 cm). ☐Yes = Category I ☒No = Not a forested wetland for this section Cat. I SC 5.0. Wetlands in Coastal Lagoons Does the wetland meet all of the following criteria of a wetland in a coastal lagoon? ☐ The wetland lies in a depression adjacent to marine waters that is wholly or partially separated from marine waters by sandbanks, gravel banks, shingle, or, less frequently, rocks ☐ The lagoon in which the wetland is located contains ponded water that is saline or brackish (> 0.5 ppt) during most of the year in at least a portion of the lagoon (needs to be measured near the bottom) ☐Yes – Go to SC 5.1 ☒No = Not a wetland in a coastal lagoon SC 5.1. Does the wetland meet all of the following three conditions? ☐ The wetland is relatively undisturbed (has no diking, ditching, filling, cultivation, grazing), and has less than 20% cover of aggressive, opportunistic plant species (see list of species on p. 100). ☐ At least ¾ of the landward edge of the wetland has a 100 ft buffer of shrub, forest, or un-grazed or un- mowed grassland. ☐ The wetland is larger than 1/10 ac (4350 ft2) ☐Yes = Category I ☐No = Category II Cat. I Cat. II SC 6.0. Interdunal Wetlands Is the wetland west of the 1889 line (also called the Western Boundary of Upland Ownership or WBUO)? If you answer yes you will still need to rate the wetland based on its habitat functions. In practical terms that means the following geographic areas: ☐ Long Beach Peninsula: Lands west of SR 103 ☐ Grayland-Westport: Lands west of SR 105 ☐ Ocean Shores-Copalis: Lands west of SR 115 and SR 109 ☐Yes – Go to SC 6.1 ☒No = not an interdunal wetland for rating SC 6.1. Is the wetland 1 ac or larger and scores an 8 or 9 for the habitat functions on the form (rates H,H,H or H,H,M for the three aspects of function)? ☐Yes = Category I ☐No – Go to SC 6.2 SC 6.2. Is the wetland 1 ac or larger, or is it in a mosaic of wetlands that is 1 ac or larger? ☐Yes = Category II ☐No – Go to SC 6.3 SC 6.3. Is the unit between 0.1 and 1 ac, or is it in a mosaic of wetlands that is between 0.1 and 1 ac? ☐Yes = Category III ☐No = Category IV Cat I Cat. II Cat. III Cat. IV Category of wetland based on Special Characteristics If you answered No for all types, enter “Not Applicable” on Summary Form NA Wetland Rating System for Western WA: 2014 Update Rating Form – Effective January 1, 2015 12 Wetland name or number: Wetland C This page left blank intentionally 2014 Ecology Wetland Rating Form Figures C HELAN AVENUE NE Wetlands B and C (Depressional) .................................................................................................................. 1 Figure 1. Cowardin plant classes – D1.3, H1.1, H1.4 ................................................................................ 1 Figure 2. Hydroperiods, outlet(s), and 150-ft area – D1.1, D1.4, H1.2, D2.2, D5.2 .................................. 2 Figure 3. Map of the contributing basins – D4.3, D5.3 ............................................................................. 3 Figure 4a. Wetland B: Undisturbed habitat, high-intensity land uses, and moderate-low intensity land uses within 1 km from wetland edge including polygon for accessible habitat – H2.1, H2.2, H2.3 ........................................................................................................................................ 4 Figure 4b. Wetland C: Undisturbed habitat, high-intensity land uses, and moderate-low intensity land uses within 1 km from wetland edge including polygon for accessible habitat – H2.1, H2.2, H2.3 ........................................................................................................................................ 5 Figure 5. Screen-capture of 303(d) listed waters in basin – D3.1, D3.2 ................................................... 6 Figure 6. Screen-capture of WQ improvement projects (none) in sub-basins in which units are found. – D3.3 ..................................................................................................................................... 7 Page left blank intentionally to allow for duplex printing. Features depicted are not to scale. Sketches are based on available data and best professional judgment. Wetland Figures - 1 WETLANDS B AND C (DEPRESSIONAL) Figure 1. Cowardin plant classes – D1.3, H1.1, H1.4 Palustrine Emergent (not 10%) Palustrine Scrub-shrub Palustrine Forested Features depicted are not to scale. Sketches are based on available data and best professional judgment. Wetland Figures - 2 Figure 2. Hydroperiods, outlet(s), and 150-ft area – D1.1, D1.4, H1.2, D2.2, D5.2 Saturated only Occasionally flooded Boundaries of areas within 150-feet Outlet Outlet Seasonally flooded Features depicted are not to scale. Sketches are based on available data and best professional judgment. Wetland Figures - 3 Figure 3. Map of the contributing basins – D4.3, D5.3 Wetland B contributing basin Wetland B Wetland C Wetland C contributing basin Features depicted are not to scale. Sketches are based on available data and best professional judgment. Wetland Figures - 4 Figure 4a. Wetland B: Undisturbed habitat, high-intensity land uses, and moderate-low intensity land uses within 1 km from wetland edge including polygon for accessible habitat – H2.1, H2.2, H2.3 High-intensity land use (no shade) Moderate-low intensity land use (blue) Undisturbed habitat (green) Boundary of area within 1 km Accessible moderate-low habitat (purple line) Features depicted are not to scale. Sketches are based on available data and best professional judgment. Wetland Figures - 5 Figure 4b. Wetland C: Undisturbed habitat, high-intensity land uses, and moderate-low intensity land uses within 1 km from wetland edge including polygon for accessible habitat – H2.1, H2.2, H2.3 High-intensity land use (no shade) Moderate-low intensity land use (blue) Undisturbed habitat (green) Boundary of area within 1 km Accessible moderate-low habitat (purple line) Features depicted are not to scale. Sketches are based on available data and best professional judgment. Wetland Figures - 6 Figure 5. Screen-capture of 303(d) listed waters in basin – D3.1, D3.2 Approximate location of wetlands Features depicted are not to scale. Sketches are based on available data and best professional judgment. Wetland Figures - 7 Figure 6. Screen-capture of WQ improvement projects (none) in sub-basins in which units are found. – D3.3 Approximate location of wetlands