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HomeMy WebLinkAboutF_RS_TIR_180503.pdf Prepared for: iCap Lakeview, LLC 3535 Factoria Blvd Suite 500 Bellevue, WA 98006 Prepared by: CPH Consultants Bryce Bessette, PE and Jamie Schroeder, PE 11431 Willows Road NE Suite 120 Redmond, WA 98052 May 1, 2018 Final Technical Information Report Senza Lakeview Subdivision 3907 Park Avenue N City of Renton, Washington R-3934PR-16000315 LUA-16000165 U-16006676 FINAL IN COMPIANCE WITH CITY OF RENTON STANDARDS DEVELOPMENT ENGINEERING Ann Fowler 05/04/2018 SURFACE WATER UTILITY rstraka 05/08/2018 11431 WILLOWS ROAD NE, SUITE 120 REDMOND, WA 98052 P: (425) 285-2390 | F: (425) 285-2389 www.cphconsultants.com Site Planning Civil Engineering Project Management Land Development Consulting SENZA LAKEVIEW RENTON, WASHINGTON FINAL TECHNICAL INFORMATION REPORT May 1, 2018 Prepared For: iCap Lakeview, LLC 3535 Factoria Blvd SE, Suite 500 Bellevue, WA 98006 Prepared By: CPH Consultants Jamie B. Schroeder, PE Bryce Bessette, PE CPH Project No. 0139-15-001 Site Planning Civil Engineering Project Management Land Development Consulting TECHNICAL INFORMATION REPORT SENZA LAKEVIEW CITY OF RENTON, WA TABLE OF CONTENTS SECTION 1 – PROJECT OVERVIEW 3 FIGURE 1 – VICINITY MAP FIGURE 2 – TIR WORKSHEET SECTION 2 – CONDITIONS AND REQUIREMENTS SUMMARY 9 SECTION 3 – OFFSITE ANALYSIS 11 SECTION 4 – FLOW CONTROL AND WATER QUALITY FACILITY ANALYSIS AND DESIGN 13 SECTION 5 – CONVEYANCE SYSTEM ANALYSIS AND DESIGN 18 SECTION 6 – SPECIAL REPORTS AND STUDIES 19 GEOTECHNICAL REPORT, BY EARTH SOLUTIONS, INC. (SEPTEMBER 17, 2015) CRITICAL AREA DETERMINATION REPORT, BY WETLAND RESOURCES, INC. (APRIL 5, 2016) FISH PASSAGE SCREEN LETTER, BY WETLAND RESOURCES, INC. (APRIL 15, 2016) ILLUMINATION CALCULATIONS, BY TENW (DECEMBER 14, 2016) TRAFFIC REPORT, BY TENW (DECEMBER 14, 2016) ARBORIST REPORT/TREE PLAN, BY AMERICAN FOREST MANAGEMENT (FEBRUARY 9, 2016) SECTION 7 – OTHER PERMIT 20 SECTION 8 – CSWPPP ANALYSIS AND DESIGN 21 SECTION 9 – BOND QUANTITIES, FACILITY SUMMARIES, AND DECLARATION OF COVENANT 23 SECTION 10 – OPERATIONS AND MAINTENANCE MANUAL 24 FIGURES FIGURE 3 – EXISTING SITE CONDITIONS FIGURE 4 – DEVELOPED SITE CONDITIONS FIGURE 5 – DRAINAGE BASINS FIGURE 6 – UPSTREAM BASINS FIGURE 7 – SUB-BASINS FIGURE 8 - DOWNSTREAM MAP Site Planning Civil Engineering Project Management Land Development Consulting APPENDICES APPENDIX A – NRCS SOILS REPORT APPENDIX B – WWHM REPORTS APPENDIX C – PROJECT SITE AND UPSTREAM LAND USE SUMMARIES APPENDIX D – STORMFILTER PARAMETERS SUMMARY APPENDIX E – CONVEYANCE BACKWATER ANALYSIS APPENDIX F – OFFSITE ANALYSIS TABLE AND DOWNSTREAM PHOTOS APPENDIX G – NPDES PERMIT APPENDIX H – BARBEE MILL OFFSITE BNSF RAILROAD BYPASS ANALYSIS Senza Lakeview Final Technical Information Report CPH Project No. 0139-15-001 May 1, 2018 CP|H CONSULTANTS Page 3 SECTION 1 – PROJECT OVERVIEW This Technical Information Report (TIR) is provided to describe the stormwater conditions and proposed drainage improvements for the Senza Lakeview project. The project proposes to subdivide and redevelop four existing properties into seventeen individual single-family residential parcels within the City of Renton. This report is provided to identify the applicable storm drainage standards and to summarize the analyses and design provisions proposed for the project to comply with city surface water standards. The information provided within this TIR represents the basis of design for the storm drainage systems and surface water conditions for the project. The project is located in the northern tip of the City of Renton. The vicinity map provided below as Figure 1 illustrates the general location of the property along Lake Washington BLVD N to the west, Park Ave N to the east and North 40th St to the north. The street address of the project site is 3907 Park Ave N (King County tax parcel nos. 334270-0415, -0420, -0425, and -0427). More generally, the site is located in the SW ¼ of the NW ¼ of Section 32 of Township 24 North, Range 5 East, in King County, Washington (see Vicinity Map below). Figure 1– Location/Vicinity Map – Not to Scale Senza Lakeview Final Technical Information Report CPH Project No. 0139-15-001 May 1, 2018 CP|H CONSULTANTS Page 4 The project site is comprised of 4 parcels; approximately 3.83 acres. A total of 3 single-family homes are currently on the project site. A number of trees of varying type, age, and health condition exist on the site. Figure 3 in the Appendix displays the existing site conditions. The proposed subdivision will create a total of seventeen (17) single-family residential lots. In addition, the project will include frontage improvements on Lake Washington Blvd N, Park Ave N and N 40th St to widen and add concrete curb, gutter, and sidewalk. Total site impervious coverage for individual lots is limited to 55% by the current site zoning. The storm drainage analysis performed for this report considered this maximum coverage. The proposed site plan is shown in Figure 4. The developed site is required to provide Basic Water Quality treatment in addition to Level 1 (i.e., basic) flow control per current City of Renton surface water standards. Water quality storm volumes are proposed to be treated with a Contech StormFilter vault in the northwest corner of the site. The runoff from the frontage improvements and half street grind and overlay along Park Ave N. will be treated by a Contech StormFilter catchbasin system near the corner of Park Ave N. and N. 40th St. The site qualifies for the Direct Discharge Exemption as the flowpath from the project site discharge point is less than a half mile to the 100-year floodplain of Lake Washington. This exemption is discussed further in section 2, Flow Control. All of the storm water runoff from the improved site will be collected, controlled, and released to the existing 18” concrete pipe located at the intersection of Lake Washington BLVD N and N 40th St. A series of on-site catch basin inlets and underground pipes will collect and convey surface water runoff westerly within proposed road right-of-way for the majority of the developed site to the Contech StormFilter for water quality treatment. A portion of the runoff along Lake Washington BLVD N will be bypassed due to the existing topography and grade of the roads. However, to offset this untreated area, the site will be treating a larger runoff area from existing previously untreated pavement along N 40th St. This treatment trade meets the requirements set forth by the City of Renton standards. Storm drainage controls for this project are proposed in accordance with City of Renton surface water standards, including recent adoption of the 2009 King County Surface Water Design Manual and the COR Addendum to that manual (KCSWDM). On-site Soil Conditions The soils of the area are characterized generally by the Natural Resource Conservation Services (NCRS) as Alderwood gravelly sandy loam (AgC) and Indianola loamy sand (InC). A site-specific investigation of the existing site geotechnical conditions was performed by Earth Solutions NW, LLC. A copy of the NRCS soils report is provided in Appendix A of this report for reference. Senza Lakeview Final Technical Information Report CPH Project No. 0139-15-001 May 1, 2018 CP|H CONSULTANTS Page 5 Figure 2 – Technical Information Report (TIR) Worksheet, 2009 Surface Water Design Manual Part 1 PROJECT OWNER AND PROJECT ENGINEER Part 2 PROJECT LOCATION AND DESCRIPTION Project Owner: Barbara Rodgers, iCap Lakeview, LLC Project Name: Senza Lakeview Phone: (425) 278-9030 DDES Permit #: ______________________ Address: 10900 NE 8th St, 10th Floor Bellevue, WA 98005 Location: Township: 24 N Range: 5 E Project Engineer: Jamie Schroeder Section: 32 Phone: (425) 285-2390 Site Address: 1129 N 40th St. Renton, WA Part 3 TYPE OF PERMIT APPLICATION Part 4 OTHER REVIEWS AND PERMITS ■ Landuse Services  DFW HPA  Shoreline Subdivision / Short Subd. / UPD  COE 404 Management  Building Services  DOE Dam Safety  Structural M/F / Commercial / SFR  FEMA Floodplain Rockery/Vault/ ____  Clearing and Grading  COE Wetlands  ESA Section 7  Right-of-Way Use  Other _______________________________ ◼ Other: Shoreline Substantial Development Part 5 PLAN AND REPORT INFORMATION Technical Information Report Site Improvement Plan (Engr. Plans) Type of Drainage Full / Targeted / Type (circle one): Full / Modified / Review (circle): Large Site Small Site Date (include revision Date (include revision dates): 12/15/2016 dates): Date of Final: Date of Final: Part 6 ADJUSTMENT APPROVALS Type (circle one): Standard / Complex / Preapplication / Experimental / Blanket Description: (include conditions in TIR Section 2) Date of Approval: _____________________________ Senza Lakeview Final Technical Information Report CPH Project No. 0139-15-001 May 1, 2018 CP|H CONSULTANTS Page 6 Figure 2 – Technical Information Report (TIR) Worksheet, 2009 Surface Water Design Manual (cont’d.) Part 7 MONITORING REQUIREMENTS Monitoring Required: Yes / No Describe: Start Date: Completion Date: Part 8 SITE COMMUNITY AND DRAINAGE BASIN Community Plan: Residential R-6 Special District Overlays: None Drainage Basin: May Creek Stormwater Requirements: Basic Flow Part 9 ONSITE AND ADJACENT SENSITIVE AREAS  River/Stream ◼ Steep Slope Regulated  Lake  Erosion Hazard  Wetlands ◼ Landslide Hazard Moderate  Closed Depression  Coal Mine Hazard  Floodplain  Seismic Hazard  Other  Habitat Protection Part 10 SOILS Soil Type Slopes Erosion Potential AgC 8% - 15% Yes InC 5% - 15% Yes  High Groundwater Table (within 5 feet)  Sole Source Aquifer  Other __________________  Seeps/Springs  Additional Sheets Attached Senza Lakeview Final Technical Information Report CPH Project No. 0139-15-001 May 1, 2018 CP|H CONSULTANTS Page 7 Figure 2 – Technical Information Report (TIR) Worksheet, 2009 Surface Water Design Manual (cont’d.) Part 11 DRAINAGE DESIGN LIMITATIONS REFERENCE LIMITATION / SITE CONSTRAINT  Core 2 – Offsite Analysis  Sensitive/Critical Areas  SEPA  Other   Additional Sheets Attached Part 12 TIR SUMMARY SHEET (provide one TIR Summary Sheet per Threshold Discharge Area) Threshold Discharge Area: (name or description) Wetland Core Requirements (all 8 apply) Discharge at Natural Location Number of Natural Discharge Locations: 1 Offsite Analysis Level: 1 / 2 / 3 Dated: ___________ Flow Control Level: 1 / 2 / 3 or Exemption Number: Direct Discharge (include a facility summary sheet) Small Site BMP’s: _Full Dispersion_____________________ Conveyance System Spill containment located at: Erosion and Sediment Control ESC Site Supervisor: TBD Contact Phone: After Hours Phone: Maintenance and Operation Responsibility: Private / Public If Private, Maintenance Log Required: Yes / No Financial Guarantees and Liability Provided: Yes / No Water Quality Type: Basic / Sens. Lake / Enhanced Basic / Bog (include facility summary sheet) or Exemption No. _______________________ Landscape Management Plan: Yes / No Special Requirements (as applicable) Area Specific Drainage Type: CDA / SDO / MDP / BP / LMP / Shared Fac / None Requirements Name: ________________________________ Floodplain/Floodway Delineation Type: Major / Minor / Exemption / None 100-year Base Flood Elevation (or range): _______________ Datum: Flood Protection Facilities Description: Source Control Describe landuse: Residential (comm./industrial landuse) Describe any structural controls: Oil Control High-use Site: Yes / No Treatment BMP: __________________________________ Maintenance Agreement: Yes / No with whom?: Other Drainage Structures Describe: Senza Lakeview Final Technical Information Report CPH Project No. 0139-15-001 May 1, 2018 CP|H CONSULTANTS Page 9 SECTION 2 – CONDITIONS AND REQUIREMENTS SUMMARY Compliance with Project Drainage Requirements The storm drainage and temporary erosion control standards for the project are established by the City of Renton Addendum to the 2009 King County Surface Water Design Manual (KCSWDM). The project requires Full Drainage Review as it exceeds the impervious threshold for Small Site Review (Type I or Type II) and proposes more than 2,000 square feet of new impervious surface coverage. The KCSWDM specifies eight core and six special requirements that are to be met for this project. Compliance and/or applicability of each of these design standards are summarized below: SWDM Core Requirements 1. Discharge at Natural Location: The project site currently slopes and drains northwesterly to a ditch then to a catch basin at the intersection of Lake Washington BLVD N and N 40th St at the northwestern corner of the site. Roof drains, yard drains and catch basins will convey runoff to the existing stormwater conveyance system mentioned above. On-site storm water will maintain this existing drainage pattern and ultimate downstream discharge in accordance with current flow control standards. 2. Offsite Analysis: Summarized in Section 3 – Off-site Analysis. 3. Flow Control: The project requires Level 1 (i.e., Basic) flow control according to the KCSWDM Flow Control Map. The location of the site is in close proximity to Lake Washington with the discharge point less than a half mile from the 100-yr floodplain of Lake Washington. Therefore it qualifies for the Direct Discharge Exemption per the requirements set forth in the KCSWDM section 1.2.3.1 and the City of Renton adopted version of the KCSWDM. A detailed description of the of the exemption and calculations of runoff flow rates are provided in Section 4 – Flow Control and Water Quality Facility Analysis and Design. 4. Conveyance System: The project proposes to collect on-site runoff and convey it to the proposed on- site stormfilter vault at the northwest corner of the site. The runoff from the frontage improvements and half street grind and overlay along Park Ave N. will be treated by a Contech StormFilter catchbasin system near the corner of Park Ave N. and N. 40th St. These improvements are shown in Figures 4 and 5 and are described further in Section 5 – Conveyance System Analysis and Design. 5. Erosion and Sediment Control: Temporary controls are as described in Section 8 – CSWPPP Analysis and Design. 6. Maintenance and Operations: The on-site storm drainage facilities are proposed to be publicly maintained. Refer to Appendix A of the King County Surface Water Design Manual for the Maintenance Requirements. 7. Financial Guarantees and Liability: A Bond Quantity Worksheet will be prepared for this project prior to the final engineering package. Approval and all financial guarantees will be provided by the developer. 8. Water Quality: Basic Water Quality treatment is required for the proposed project. This treatment level is to be achieved by means of a Stormfilter vault and StormFilter catchbasin as shown on Figures Senza Lakeview Final Technical Information Report CPH Project No. 0139-15-001 May 1, 2018 CP|H CONSULTANTS Page 10 4 and 5 and as described in Section 4 – Flow Control and Water Quality Facility Analysis and Design. The Stormfilter vault is preceded by a Contech CDS presettling manhole. KCSWDM Special Requirements 1. Other Adopted Area-Specific Requirements: No area-specific requirements apply to this project site. Preliminary Plat Approval is provided in the appendix 2. Flood Hazard Area Delineation: The limits of this project are not located within or in proximity to a 100-year floodplain. 3. Flood Protection Facilities: Not applicable. 4. Source Control: No additional source control is proposed. 5. Oil Control: The project is not considered a high-use area and no special oil control provisions are required. 6. Aquifer Protection Areas: The project is not within an aquifer protection area per the City of Renton (COR) interactive maps. Senza Lakeview Final Technical Information Report CPH Project No. 0139-15-001 May 1, 2018 CP|H CONSULTANTS Page 11 SECTION 3 – OFF-SITE ANALYSIS Task 1: Study Area Definition and Maps The proposed project site is located at 3907 Park Ave N in Renton, WA. The site is currently developed with three single-family homes, a gravel driveway and various outbuildings. The existing ground cover consists mostly of grass with various trees of varying age and health. The existing site topography consists of slopes ranging from 0% to 15%. The existing site conditions are shown in Figure 3. The project site currently slopes and drains north and west to a ditch and catch basin at the intersection of Lake Washington BLVD N and N 40th St at the northwest corner of the site. The ditch gradually slopes north along Lake Washington BLVD N. No water was observed in the ditch during the site visit and was lined with grass. Once the runoff enters the existing conveyance system it flows northwesterly for approximately 540’ through a series of concrete pipes of varying sizes until it discharges into Lake Washington. The conveyance system was observed to be in good working order and no indications of overtopping, excessive sediment transport, or flooding was observed during our site visit. Task 2: Resource Review King County iMAP and the City of Renton (COR) Maps and GIS Data were reviewed to identify any potential sensitive areas in the proximity of the project site. • Wetlands: iMap does not identify any wetlands on the project site. • Streams and 100-year Floodplain: The project site is not located in the 100-year floodplain. • Erosion Hazard Areas: COR Maps identifies no erosion hazard areas on the project site. • Seismic Hazard Areas: COR Maps identifies no seismic hazard areas on the project site. • Coal Mine Hazard Areas: COR Maps identifies no coal mine hazard areas on the project site. • Critical Aquifer Recharge Area: The project site is not located within a critical aquifer recharge area per iMAP records • Basin Condition: iMap indicates the majority of the site as a high basin condition. The southwest corner of the project site is indicated as a low basin condition. • Areas Susceptible to Groundwater Contamination: iMap does not show the project site as being susceptible to groundwater contamination. Task 3: Field Inspection A field inspection was performed on Monday, January 25, 2016 on a sunny day with a temperature of approximately 52 degrees. The site is currently developed with three single-family homes with landscaped yards, a gravel driveway and various outbuildings. The majority of the site slopes west to a grass lined ditch along the western boundary of the site along Lake Washington BLVD N. A small area along the northern boundary of the site slopes northwesterly along N 40th St to a catch basin at the intersection of N 40th St and Lake Washington BLVD N. Onsite Drainage Basin The existing topography of the site has slopes ranging from 0% to 15% over most of its area. The project site is comprised of a single drainage basin with surface runoff traveling primarily as sheet and shallow concentrated flows over pervious areas. The drainage basin is comprised mostly of grass along with three Senza Lakeview Final Technical Information Report CPH Project No. 0139-15-001 May 1, 2018 CP|H CONSULTANTS Page 12 single-family homes, various outbuildings, landscaped areas and a gravel driveway. Based on visual inspection during the site visit and survey contour data there are no low points where runoff can collect on site. Task 4: Drainage System Description Downstream Basin Excess runoff from the drainage basin is conveyed north and west across the adjacent properties via sheet flow until it reaches an existing ditch along Lake Washington BLVD N and a catch basin near the northwest corner of the site. Flow from the ditch enters the catch basin at the intersection through a 62’ long 18” concrete pipe. The catch basin also receives overland flow from runoff along the north boundary of the site and N 40th St. The stormwater then flows north and west for approximately 125’ through a series of 15” and 18” concrete pipes with slopes ranging from 3.8% to 25% to a 49’ long 24” DI pipe which conveys the flows west under an existing BNSF railroad. Just west of the railroad the stormwater discharges to a ditch for approximately 25’ before entering a 24” concrete pipe. From here, the stormwater flows west and south through a series of 24” and 30” concrete pipes with slopes ranging from 0.26% to 6.2% for approximately 340’ before ultimately discharging into Lake Washington approximately 540’ downstream from the project site discharge point. A downstream map is shown in Figure 7. Upstream Basin Based on the site visit and information obtained from the previous Barbee Mill project it was determined the project site drainage basin is at the downstream end of a larger basin. The upstream basin was analyzed to determine the affect runoff could potentially have on the project site. The total impervious area and overall basin area were determined in order to calculate total runoff upstream of the project site. Based on the site visit and survey contour data, surface runoff from the upstream basin does not flow onto the project site. The upstream analysis is discussed further in Section 4 – Flow Control and Water Quality Facility Analysis and Design. Total and impervious area information for the upstream basin can be obtained from Figure 6. Task 5: Downstream Drainage Problems The three types of drainage problems analyzed are: conveyance system nuisance problem (Type 1), severe erosion problem (Type 2), and severe flooding problem (Type 3). A backwater analysis was performed using the rational method to determine the effects on the existing stormwater system as a result from the added impervious areas from the project site. Based on these results it was determined that two 15” conveyance pipes within the Lake Washington BLVD. and N. 40th St. ROW were undersized and created overtopping conditions during the 100-yr storm event for catch basins immediately upstream. To eliminate potential overtopping the existing undersized pipes will be upsized to 18 inches. With the 18” pipes the system can safely and effectively convey the increased runoff for the 100-yr storm event generated by the additional imperious areas from the project site without overtopping. Based on the site visit and information obtained from King County iMap, the City of Renton (COR) interactive Maps, and the Barbee Mill drainage report it was determined there are no potential downstream drainage problems as a result from the increased impervious surfaces developed by the project after the two undersized conveyance pipes are upsized. Senza Lakeview Final Technical Information Report CPH Project No. 0139-15-001 May 1, 2018 CP|H CONSULTANTS Page 13 SECTION 4 – FLOW CONTROL AND WATER QUALITY FACILITY ANALYSIS AND DESIGN The hydrologic analysis of the runoff conditions for this project is based on drainage characteristics such as basin area, soil type, and land use (i.e., pervious vs. impervious) for the project site as well as areas upstream of the project site. The upstream basin areas and locations were based off the drainage report generated for the Barbee Mill Townhomes project. The Western Washington Hydraulic Model (WWHM) software was used to evaluate the storm water runoff conditions for the project site and upstream basins to verify that the existing conveyance system could safely and efficiently convey flows downstream of the site. The following is a summary of the results of the analysis and the proposed drainage facility improvements for this project. Existing Site Hydrology The existing site conditions are shown in Figure 3 of the Appendix. Existing site conditions within the area were modeled based on the basin configurations summarized in Table 4.1 below. The Western Washington Hydraulic Model (WWHM) software was used to model the existing site hydrology and calculate runoff peak rates. The results of the existing site runoff analysis are provided in Appendix B. Table 4.1 – Land Use Cover, Existing Site Conditions Basin ID Total Area (AC) Land Cover (AC) Impervious Till Forest Till Grass Site Basin 4.07 0.42 0.00 3.65 Additionally, historic site (i.e., fully forested) conditions would be considered in the analysis of the pre- developed conditions for all on-site targeted developed surfaces in accordance with KCSWDM standards for Basic Flow Control. However our project meets the exemption for flow control. The existing land use conditions summarized in Table 4.2 are summarized for reference. Table 4.2 – Land Use Cover, Pre-Developed Site Conditions Basin ID Total Area (AC) Land Cover (AC) Impervious Till Forest Till Grass Site Basin 4.11 0 4.11 0 Bypass Basin 0.04 0 0.04 0 Additional Intake Basin 0.07 0 0.07 0 Total 4.22 0 4.22 0 The basin site area totals 4.22 acres but includes a small 0.04 acre segment, delineated as Bypass Basin in Figure 5 that will be bypassed due to the grades of the site. However, an additional 0.07 acres, delineated as Additional Intake Basin in Figure 5 that is located off-site will be passed through the on-site facility and treated for water quality. Any areas widening or improved were modeled as forest for existing conditions. Input and output parameters for this model are provided in Appendix B of this report. Senza Lakeview Final Technical Information Report CPH Project No. 0139-15-001 May 1, 2018 CP|H CONSULTANTS Page 14 Developed Site Hydrology The site is planned to be improved with roadway, storm drainage, and utility infrastructure in support of seventeen (17) new single-family residences. Frontage improvements on Lake Washington BLVD N, N 40th St and Park Ave N will be completed in accordance with city road standards as conditions with the preliminary plat approval. The developed site drainage is contained within one basin. The developed conditions of the site were modeled using the WWHM modeling software. The majority of the roads, building roof drains, on-site paved surfaces and most landscape areas on the site are collected and directed to the on-site water quality Contech StormFilter. The runoff from the frontage improvements and new pollution generating impervious surfaces along Park Ave N. will be treated by a Contech StormFilter catchbasin system and discharges into an existing catch basin near the corner of Park Ave N. and N. 40th St. The building roof drains for lots 14-17 are routed to the existing catch basin near the corner of Park Ave N. and N. 40th St. as the runoff from roofs are not considered pollution generating and do not mix with pollution generating runoff. Due to the existing topography and roadway grades, a small portion of runoff from Lake Washington BLVD will be bypassed. However, as discussed in the Existing Conditions section and later in the Water Quality section, a treatment trade is used to negate this bypass area. Fully developed conditions were modeled using measured and land cover standards established by the current Zoning Code, which states that all lot areas are assumed to be 55% impervious and 45% grass. The impervious and pervious areas for all other areas were calculated directly by measuring the new roads and sidewalks as impervious and grass areas as pervious. In order to utilize the Direct Discharge Exemption per the requirements set forth in the KCSWDM section 1.2.3.1 the basins upstream and downstream of the project site were analyzed to determine flow rates for the developed project. The upstream locations were based off the drainage report generated for the Barbee Mill Townhomes project which is located a few hundred feet northwest of the project site. The basin areas were determined using GIS and LIDAR information. It was determined that 30.41 acres upstream of the project site delineated as Basin A, 0.78 acres just downstream of the project site delineated as Basin BNSF, 0.05 acres downstream delineated as a Tributary Basin, and 1.00 acres delineated as Basin C from the Barbee Mill development utilize the same conveyance system the subject project will discharge to. Existing developed conditions were modeled using 55% impervious, 45% lawn for on-lot areas and 90% impervious, 10% lawn for areas within the right-of-way. The upstream basin, Basin A was divided into 5 sub-basins to more accurately determine the dwelling unit densities. These densities were determined by dividing the number of dwelling units by the basin area. A portion of Basin B is within a BNSF R.O.W and a portion is with the Lake Washington BLVD N right-of-way as no dwelling units are present. The sub-basin information is summarized in table 4.3 below: Table 4.3 – Land Use Cover, Existing Upstream Developed Conditions Basin ID Total Area (AC) DU/GA Impervious (AC) Lawn (AC) Project Basin 4.42 6.00 2.43 1.99 Basin A1 4.72 3.24 2.67 2.05 Basin A2 10.15 4.10 6.13 4.02 Basin A3 10.78 3.08 6.53 4.25 Senza Lakeview Final Technical Information Report CPH Project No. 0139-15-001 May 1, 2018 CP|H CONSULTANTS Page 15 Basin A4 3.07 4.53 1.83 1.24 Basin A5 1.69 4.73 1.06 0.62 BNSF Basin 0.78 0.00 0.41 0.37 Tributary Basin 0.05 0.00 0.03 0.02 The results of the developed site runoff analysis for the project site and upstream basins are summarized in Table 4.4 and more detailed results are provided in Appendix C. Table 4.4 – Runoff Flowrates Basin 100-yr Flowrate (cfs) Project Basin 2.87 Basin A 20.59 BNSF Basin 0.50 Tributary Basin 0.04 A summary of the land use areas used to model Basins A and B is shown in Figure 6. Flow Control The project site qualifies for the Direct Discharge Exemption per the requirements set forth in the KCSWDM section 1.2.3.1. The storm drainage from the City’s roads and the overall drainage basin to the east have historically (several decades from data available) flowed across the BNSF railroad right-of-way at this location. Ownership was recently taken by King County Parks, but the conveyance across this property has not changed. There is currently ROW or recorded public drainage easements upstream and downstream of the old railroad crossing. A renewable special use permit is being pursued through the King County permitting department for parcel no. 3224059005. A backwater analysis was performed using the rational method to determine the effects on the existing stormwater system as a result from the added impervious areas from the project site. Based on these results it was determined that two 15” conveyance pipes within the Lake Washington BLVD. and N. 40th St. ROW were undersized and created overtopping conditions during the 100-yr storm event for catch basins immediately upstream. To eliminate potential overtopping, the existing undersized pipes will be upsized to 18 and 24 inches. With the 18” and 24” pipes the system can safely and effectively convey the increased runoff for the 100-yr storm event generated by the additional impervious areas from the project site without overtopping. These two conveyance pipes are identified in the backwater analysis and Figure 7 as the pipe segments between CB134294 and CB145 (upsized to 18”) and between CB134293 and CB134294 (upsized to 24”). As a result, no flow control facilities are proposed for this project and the runoff will discharge directly to Lake Washington. A breakdown of the flowrates is as follows: approximately 16.31 cfs of runoff is generated from the upstream Basins A2, A3, and A4. From this, based on the topography of the area approximately 2/3 of the 16.31 cfs is assumed to flow within the conveyance system along the east side of Park Ave N. This is Senza Lakeview Final Technical Information Report CPH Project No. 0139-15-001 May 1, 2018 CP|H CONSULTANTS Page 16 approximately 10.87 cfs. The remaining 5.44 cfs and 1.17 cfs from Basin A5, combine with the 10.87 cfs from the east side of Park Ave N at CB134265. As the conveyance system flows west an additional 0.28 cfs of runoff is collected from the west side of Park Ave N. and combines with the 17.48 cfs at CB134263 totaling 17.76 cfs. At CB 134294 the 17.76 cfs, 2.59 cfs from the project site, and 3.11 cfs from Basin A1 combine totaling 23.46 cfs. At CB132959 an additional 0.50 cfs of runoff is collected from the BNSF Basin totaling 23.96 cfs. Flows from the BNSF Basin travel west and receive 0.04 cfs additional runoff from the Tributary Basin total 24.00 cfs at proposed Catch Basin CB310 before continuing west towards the outfall. Upon reviewing the Barbee Mill Offsite BNSF Railroad Bypass Analysis, provided in Appendix H of this report, it has been determined that additional downstream flows are introduced prior to discharge into Lake Washington. At CB114823 approximately 0.04 cfs is collected from a driveway to the south, totaling 24.04 cfs. Additionally, 0.80 cfs from Parcel C of the Barbee Mill development combines with the 24.04 cfs at CB114824. This results in 24.84 cfs of runoff discharging into Lake Washington Water Quality The KCSWDM requires that all proposed projects assess the requirement to provide water quality facilities to treat runoff of pollution-generating impervious surfaces. Storm drainage runoff from pollution generating impervious surfaces (PGIS) will require Basic Water Quality treatment prior to discharge to the downstream, off-site system. This treatment level is proposed to be achieved by a Stormfilter vault preceded by a Contech CDS presettling manhole located at the northwest corner of the project site and a StormFilter system located near the corner of N. 40th St. and Park Ave N. Basic treatment facilities are required with the developed project site. Due to the existing topography and roadway grades, a small portion of runoff from Lake Washington BLVD will be bypassed. However, to offset this untreated area, the site will be treating a larger runoff area from existing previously untreated pavement along N 40th St. Section 1.2.8.2C in the COR Addendum to the KCSWDM discusses treatment trades and water quality treatment. This addendum states that runoff from the target surface may be released untreated if an existing non-target surface of similar size and pollutant characteristics is treated on the site. The bypass area, shown as the Bypass Basin in Figure 5 of the Appendix, is 0.04 acres. The previously untreated area along N 40th St is shown as the Additional Intake Basin in Figure 5 of the Appendix, amounts to 0.07 acres. The developed land use conditions displayed in Table 4.5 were used as the developed site conditions for the WWHM model and shown in Figure 5 of the Appendix. A summary of the impervious and pervious area calculations for the site is also provided in Appendix C. Table 4.5 – Land Use Cover, Developed Conditions Basin ID Total Area (AC) Land Cover (AC) Impervious Till Forest Till Grass Site Basin (to WQ Vault) 4.00 2.03 0 1.97 Bypass Basin 0.04 0.04 0 0 Additional Intake Basin 0.07 0.07 0 0 StormFilter Basin 0.33 0.29 0 0.037 Total (minus bypass basin) 4.44 2.43 0 2.01 Senza Lakeview Final Technical Information Report CPH Project No. 0139-15-001 May 1, 2018 CP|H CONSULTANTS Page 17 A summary of the StormFilter vault, CDS presettling manhole, and StormFilter catchbasin parameters are provided in Appendix D of this report. The flowrates for the WQ facilities are provided in Table 4.6. Table 4.6 – WQ Flowrates Basin Area (AC) Water Quality Flowrate (cfs) StormFilter Vault 4.07 0.206 StormFilter Catch Basin 0.33 0.010 LID Flow Control Individual lot flow control devices were evaluated for this project and will be implemented during the building permit stage. • Full dispersion and infiltration were determined to be unfeasible due to limited undisturbed native vegetation and poor soil infiltration characteristics • Roof downspout dispersion – splash blocks were determined to be another potential method to retain runoff on-site. The quantity and location of splash blocks may be added on a case by case basis. • Basic dispersion and infiltration were determined to be a potential flow control device. The quantity and location of these devices may be added on a case by case basis. • Permeable Pavers have been identified as a valid BMP flow control device. For lots less than 11,000 square feet, 10% of the site/lot must be mitigated per section 5.2.1.1 of the KCSWDM. The target surface area mitigated by this BMP for each lot is identified in Figure 4. Senza Lakeview Final Technical Information Report CPH Project No. 0139-15-001 May 1, 2018 CP|H CONSULTANTS Page 18 SECTION 5 – CONVEYANCE SYSTEM ANALYSIS AND DESIGN Conveyance analysis for the project was performed in accordance with Chapter 4 of the KCSWDM which requires that new and existing pipe systems be designed with sufficient capacity to convey and contain at minimum the 25 year peak flow. The existing offsite conveyance system was analyzed to contain runoff rates generated by a 100 year storm event. The analysis begins at an existing catch basin at the corner of Lake Washington BLVD N and N 40th St. This catch basin is where flows from the project site and flows from the upstream basins combine into the existing conveyance system. The analysis terminates at the outlet to Lake Washington. The design flow rate for conveyance/backwater analysis is based on peak flow rates calculated using WWHM. Developed conditions for improved tributary areas and existing conditions for any off-site tributary areas were used for input parameters. Refer to Appendix E of this report for the backwater analysis. Surface water collection and conveyance for the project is proposed by means of grading, grated inlets, and below grade pipes. The majority of the roads, building roof drains, on-site paved surfaces and most landscape areas on the site are collected and directed to the on-site water quality Contech StormFilter. Stormwater from the vault will discharge to an existing manhole at the southeast corner of the Lake Washington BLVD N and N 40th St intersection. The runoff from the frontage improvements and pollution generating impervious surfaces along Park Ave N. will be treated by a Contech Stormfilter catchbasin system and discharges into an existing catch basin near the corner of Park Ave N. and N. 40th St. The building roof drains for lots 14-17 are routed to the existing catch basin near the corner of Park Ave N. and N. 40th St. as the runoff from roofs are not considered pollution generating and do not mix with pollution generating runoff. The extent of the backwater analysis includes the proposed conveyance system generated by the project site along with the existing conveyance system within the Lake Washington BLVD. N. and N. 40th St. right-of-ways. The upper east end of the analysis terminates at the southeast corner of the N. 40th St. and Park Ave. N. intersection at the existing catchbasin, CB134267. Due to the steep slopes of the conveyance pipes downstream of CB134267 it is likely that the system is in inlet control, therefore, the pipes can convey more flow than the inlet of the catchbasin can accept. See Figure 7 for the location of CB134267. During the downstream analysis it was determined that the length and slope of the 24” RGRCP pipe that collects runoff from the existing ditch in the King County Parks property was not updated in the Barbee Mill as-built drawings, see Figure 10. By using the as-built information (ie. station, offset, and invert elevation) for CB820 (CB114828) and the northing, easting, and invert elevation of the inlet for the 24” RGRCP pipe it was determined that the length and slope are 20.57’ and 8.21%, respectively. To avoid a utility conflict with an existing 8” water main CB310 will be placed several feet upstream from the end of the 24” RGRCP pipe and a short piece of 24” pipe of matching material will connect CB310 to the “bell” end off the existing 24” pipe. In the backwater analysis a length of 26.83’ was used as the pipe length between CB114828 and CB310 as this is the combined length of the existing and new 24” pipes. Note that the BNSF Intake and Intake #1 are within roadside ditches. Any backwater experienced by these intakes and their subsequent pipes will release to the upstream ditch. Therefore, the rim elevation used in the backwater analysis is set at the top of the ditch channel. The storm drainage conveyance systems are illustrated in Figures 4, and 5. Appendix E contains the supporting conveyance backwater analysis. Senza Lakeview Final Technical Information Report CPH Project No. 0139-15-001 May 1, 2018 CP|H CONSULTANTS Page 19 SECTION 6 – SPECIAL REPORTS AND STUDIES Geotechnical Report, by Earth Solutions, Inc., September 17, 2015 Critical Areas Determination Report, by Wetland Resources, Inc., April 5, 2016 Fish Passage Screen letter, by Wetland Resources, Inc., April 15, 2016 Illumination Calculations, by TENW, December 14, 2016 Traffic Report, by TENW, December 14, 2016 Arborist Report/Tree Plan, by American Forest Management, February 9, 2016 Site Planning Civil Engineering Project Management Land Development Consulting GEOTECHNICAL REPORT EARTH SOLUTIONS (SEPTEMBER 17, 2015) EarthSolutionsNWLLC EarthSolutionsNWLLC Geotechnical Engineering Geology Environmental Scientists Construction Monitoring 1805 -136th Place N.E.,Suite 201 Bellevue,WA 98005 (425)449-4704 Fax (425)449-4711 www.earthsolutionsnw.com GEOTECHNICAL ENGINEERING STUDY PROPOSED RESIDENTIAL DEVELOPMENT 3908 &3916 LAKE WASHINGTON BOULEVARD NORTH & 3907 PARK AVENUE NORTH RENTON,WASHINGTON ES-4088 2005 2015 Drwn. Checked Date Date Proj.No. Plate Earth Solutions NWLLC Geotechnical Engineering,Construction Monitoring EarthSolutionsNWLLC EarthSolutionsNWLLC and Environmental Sciences Vicinity Map iCAP Kennydale Plat Renton,Washington MRS KDH 09/11/2015 Sept.2015 4088 1 NORTH NOTE:This plate may contain areas of color.ESNW cannot be responsible for any subsequent misinterpretation of the information resulting from black &white reproductions of this plate. Reference: Renton,Washington Map 626 By The Thomas Guide Rand McNally 32nd Edition SITE Plate Proj.No. Date Checked By Drwn.ByEarthSolutionsNWLLCGeotechnicalEngineering,ConstructionMonitoringandEnvironmentalSciencesEarthSolutionsNWLLCEarthSolutionsNWLLCTestPitLocationPlaniCAPKennydalePlatRenton,WashingtonMRS KDH 09/15/2015 4088 2 NORTH 0 30 60 120 Scale in Feet1"=6 0' NOTE:This plate may contain areas of color.ESNW cannot be responsible for any subsequent misinterpretation of the information resulting from black &white reproductions of this plate. NOTE:The graphics shown on this plate are not intended for design purposes or precise scale measurements,but only to illustrate the approximate test locations relative to the approximate locations of existing and /or proposed site features.The information illustrated is largely based on data provided by the client at the time of our study.ESNW cannot be responsible for subsequent design changes or interpretation of the data by others. LEGEND Approximate Location of ESNW Test Pit,Proj.No. ES-4088,Sept.2015 Subject Site Existing Building PARK AVENUE N.100 9080706050 110100 908070 60 50 110 TP-1TP-2TP-3 TP-4 TP-5 TP-6 TP-7 TP-8 TP-9 LAKE WASHINGTON BLVD N.N. 40TH STREET TP-1 House Garage Shed Shed House House Rockery GravelDriveway Gravel Driveway Drwn. Checked Date Date Proj.No. Plate Earth Solutions NWLLC Geotechnical Engineering,Construction MonitoringandEnvironmentalSciences EarthSolutionsNWLLC EarthSolutionsNWLLC RETAINING WALL DRAINAGE DETAIL iCAP Kennydale Plat Renton,Washington MRS KDH 09/11/2015 Sept.2015 4088 3 NOTES: Free Draining Backfill should consist of soil having less than 5 percent fines. Percent passing #4 should be 25 to 75 percent. Sheet Drain may be feasible in lieu of Free Draining Backfill,per ESNW recommendations. Drain Pipe should consist of perforated, rigid PVC Pipe surrounded with 1" Drain Rock. LEGEND: Free Draining Structural Backfill 1 inch Drain Rock 18"Min. Structural Fill Perforated Drain Pipe (Surround In Drain Rock) SCHEMATIC ONLY -NOT TO SCALE NOT A CONSTRUCTION DRAWING Drwn. Checked Date Date Proj.No. Plate Earth Solutions NWLLC Geotechnical Engineering,Construction Monitoring and Environmental Sciences EarthSolutionsNWLLC EarthSolutionsNWLLC FOOTING DRAIN DETAIL Slope Perforated Rigid Drain Pipe (Surround with 1"Rock) 18"(Min.) NOTES: Do NOT tie roof downspouts to Footing Drain. Surface Seal to consist of 12"of less permeable,suitable soil.Slope away from building. LEGEND: Surface Seal;native soil or other low permeability material. 1"Drain Rock SCHEMATIC ONLY -NOT TO SCALE NOT A CONSTRUCTION DRAWING iCAP Kennydale Plat Renton,Washington MRS KDH 09/11/2015 Sept.2015 4088 4 Site Planning Civil Engineering Project Management Land Development Consulting CRITICAL AREAS DETERMINATION REPORT WETLAND RESOURCES, INC. (APRIL 5, 2016) Wetland Resources, Inc. iCap Senza April 7, 2016 WRI #16072 1 April 5, 2016 iCap Equity, LLC Attn: Barbara Rodgers 10900 NE 8th St, # 1000 Bellevue, WA 98004 RE: Critical Areas Determination Report for King County parcels 3342700415, 420, 425, 427 INTRODUCTION iCap Equity, LLC contracted Wetland Resources, Inc. (WRI) to perform a wetland determination within and surrounding the aforementioned 3.83-acre parcels, located in the City of Renton, WA. The purpose of the visit was to evaluate and locate jurisdictional wetlands and streams on and in the vicinity of the property, to document the findings in a brief letter, and to address off-site wetland concerns brought up during the SEPA Environmental Review public comment period. The site visit occurred on April, 1 2016. Access is from an existing driveway extending south from N 40th St. The Public Land Survey System (PLSS) locator for the subject property is Section 32, Township 24N, Range 05E, W.M. Figure 1: Aerial Overview of the Subject Property Wetland Resources, Inc. iCap Senza April 7, 2016 WRI #16072 2 METHODOLOGY Prior to conducting the site reconnaissance, public resource information was reviewed to gather background information on the subject property and the surrounding area in regards to wetlands, streams, and other critical areas. These sources include the USFWS National Wetlands Inventory (NWI), USDA/NRCS Web Soil Survey, WDFW SalmonScape Map, WDFW Priority Habitat and Species (PHS) Interactive Map, and King County iMap. • USFWS NWI Map: The NWI map does not illustrate any wetlands on the subject property. • USDA/NRCS Web Soil Survey: The Web Soil Survey indicates that the subject property is underlain by Alderwood gravelly sandy loam 8 to 15 percent slopes and Indianola loamy sand, 5 to 15 percent slopes. Neither of these soils are listed as hydric. • WDFW SalmonScape Map: The SalmonScape Map does not show any streams on the subject property. May Creek is shown approximately 750 feet north of the subject property • WDFW Priority Habitats and Species (PHS) Map: The PHS map does not illustrate any PHS species or areas on the subject property. Both Lake Washington and May Creek are identified as Priority Habitats, but are well off-site. • King Count iMap: iMap does not show any critical areas on the subject property within 200 feet. Wetland areas were determined using the routine determination approach described in the Corps of Engineers Wetlands Delineation Manual (Environmental Laboratory 1987) and the Regional Supplement to the Corps of Engineers Wetland Delineation Manual: Western Mountians, Valleys, and Coast Region (Version 2.0) (U.S. Army Corps of Engineers 2010). Under the routine methodology, the process for making a wetland determination is based on three steps: 1) Examination of the site for hydrophytic vegetation (species present and percent cover); 2) Examination of the site for hydric soils; 3) Determining the presence of wetland hydrology SITE DESCRIPTION The subject property is located between Interstate 405 and Lake Washington in the City of Renton, WA. Three existing single-family homes were recently present within the boundary of the site, but were in various stages of demolition at the time of the site visit. The property has a moderate west aspect from Park Avenue North along the eastern property boundary to Lake Washington Boulevard along the western property boundary. On-site vegetation is a mix of domestic landscaping and ornamental landscaping surrounding the old home sites and abandoned pasture/lawn areas consisting of reed canarygrass and Himalayan blackberry. Sporadic patches of native vegetation including western red cedar and willows are also present on-site. Wetland Resources, Inc. iCap Senza April 7, 2016 WRI #16072 3 RESULTS Based on the field investigation and existing available on-line resources, no wetlands or streams are located within the boundary of the investigation area or within the surrounding 200 feet, including the potential off-site area identified by the neighbor. One area of concern was observed during the site investigation. This area is dominated by a combination of reed canarygrass and Himalayan blackberry with sporadic Scouler’s willow. Soils within this area are generally very dark brown (10YR 2/2) to brown (10YY 3/3) and were moist to dry at the time of investigation (see data attached data sites). The overall lack of wetland hydrology is particularly telling given the high levels of recorded precipitation during the 2015/2016 water year. The area identified by the neighbor as a potential off-site wetland was evaluated by visual inspection from the subject property. This area is upslope of the area of concern, dominated by mowed lawn with common dandelion throughout. Immediately downslope of this area (on-site) is dominated by Himalayan blackberry (see figures 1 and 2). Based on visual observations, this off-site area does not meet the criteria for hydrophytic vegetation and therefore does not meet the definition of wetland. Figure 2: Looking off-site to the southeast. Figure 3: Looking west, stake denotes approximate property boundary. USE OF THIS REPORT This Determination Report is supplied to iCap Equity as a means of determining the presence of on-site and adjacent critical areas as required by the City of Renton. This report is based largely on readily observable conditions and, to a lesser extent, on readily ascertainable conditions. No attempt has been made to determine hidden or concealed conditions. The laws applicable to critical areas are subject to varying interpretations and may be changed at any time by the courts or legislative bodies. This report is intended to provide information deemed relevant in the applicant's attempt to comply with the laws now in effect. Wetland Resources, Inc. iCap Senza April 7, 2016 WRI #16072 4 This report conforms to the standard of care employed by wetland ecologists. No other representation or warranty is made concerning the work or this report and any implied representation or warranty is disclaimed. Wetland Resources, Inc. Scott Brainard, PWS Principal Ecologist Enclosures: Army Corps Wetland Determination Data Forms (S1 and S2) US Army Corps of Engineers Western Mountains, Valleys, and Coast – Version 2.0 WETLAND DETERMINATION DATA FORM – Western Mountains, Valleys, and Coast Region Project/Site: City/County: Sampling Date: Applicant/Owner: State: Sampling Point: Investigator(s): Section, Township, Range: Landform (hillslope, terrace, etc.): Local relief (concave, convex, none): Slope (%): Subregion (LRR): Lat: Long: Datum: Soil Map Unit Name: NWI classification: 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? 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 Hydric Soil Present? Yes No Wetland Hydrology Present? Yes No Is the Sampled Area within a Wetland? Yes No Remarks: VEGETATION – Use scientific names of plants. Absolute Dominant Indicator Tree Stratum (Plot size: ) % Cover Species? Status 1. 2. 3. 4. = Total Cover Sapling/Shrub Stratum (Plot size: ) 1. 2. 3. 4. 5. = Total Cover Herb Stratum (Plot size: ) 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. = Total Cover Woody Vine Stratum (Plot size: ) 1. 2. = Total Cover % Bare Ground in Herb Stratum Dominance Test worksheet: Number of Dominant Species That Are OBL, FACW, or FAC: (A) Total Number of Dominant Species Across All Strata: (B) Percent of Dominant Species That Are OBL, FACW, or FAC: (A/B) Prevalence Index worksheet: Total % Cover of: Multiply by: OBL species x 1 = FACW species x 2 = FAC species x 3 = FACU species x 4 = UPL species x 5 = Column Totals: (A) (B) Prevalence Index = B/A = Hydrophytic Vegetation Indicators: Rapid Test for Hydrophytic Vegetation Dominance Test is >50% Prevalence Index is ≤3.01 Morphological Adaptations1 (Provide supporting data in Remarks or on a separate sheet) Wetland Non-Vascular Plants1 Problematic Hydrophytic Vegetation1 (Explain) 1Indicators of hydric soil and wetland hydrology must be present, unless disturbed or problematic. Hydrophytic Vegetation Present? Yes No Remarks: Senza Lakeview Renton/King 4/1 iCap Equity, LLC WA S1 SB. JL 32, 24, 5 hillslope concaver <5 LRR A 47.527110 -122.202964 Alderwood gravelly sandy loam 8 to 15 % and Indianola loamy sand 5 to 15% slopes None 4 4 4 4 4 4 Precipitation levels are at 150% of normal for the water year. Alnus rubra 20 Y Fac 20 Rubus armeniacus 40 Y FacU Acer circinatum 20 Y Fac Salix scouleriana 20 Y Fac 80 Phalaris arundinacea 60 Y FacW 60 4 5 80 0 0 0 0 0 0 0 4 4 US Army Corps of Engineers Western Mountains, Valleys, and Coast – Version 2.0 SOIL Sampling Point: 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 1Type: C=Concentration, D=Depletion, RM=Reduced Matrix, CS=Covered or Coated Sand Grains. 2Location: 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) 2 cm 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) 3Indicators of hydrophytic vegetation and Sandy Mucky Mineral (S1) Depleted Dark Surface (F7) wetland hydrology must be present, Sandy Gleyed Matrix (S4) Redox Depressions (F8) unless disturbed or problematic. Restrictive Layer (if present): Type:________________________________ Depth (inches):________________________ Hydric Soil Present? Yes No Remarks: HYDROLOGY 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 (B9) (except MLRA Water-Stained Leaves (B9) (MLRA 1, 2, High Water Table (A2) 1, 2, 4A, and 4B) 4A, and 4B) 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 (D7) Sparsely Vegetated Concave Surface (B8) Field Observations: Surface Water Present? Yes No Depth (inches): Water Table Present? Yes No Depth (inches): Saturation Present? Yes No Depth (inches): (includes capillary fringe) Wetland Hydrology Present? Yes No Describe Recorded Data (stream gauge, monitoring well, aerial photos, previous inspections), if available: Remarks: S1 0-14"10YR 2/2 90 sil 14-18+"10YR 4/2 80 10YR 4/6 20 C M fsl 4 Diagnostic layer is to deep to meet the criteria for either A11 or F6 4 4 4 4 Soils were moist at the time of investigation even with higher than normal precipitation for the water year. US Army Corps of Engineers Western Mountains, Valleys, and Coast – Version 2.0 WETLAND DETERMINATION DATA FORM – Western Mountains, Valleys, and Coast Region Project/Site: City/County: Sampling Date: Applicant/Owner: State: Sampling Point: Investigator(s): Section, Township, Range: Landform (hillslope, terrace, etc.): Local relief (concave, convex, none): Slope (%): Subregion (LRR): Lat: Long: Datum: Soil Map Unit Name: NWI classification: 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? 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 Hydric Soil Present? Yes No Wetland Hydrology Present? Yes No Is the Sampled Area within a Wetland? Yes No Remarks: VEGETATION – Use scientific names of plants. Absolute Dominant Indicator Tree Stratum (Plot size: ) % Cover Species? Status 1. 2. 3. 4. = Total Cover Sapling/Shrub Stratum (Plot size: ) 1. 2. 3. 4. 5. = Total Cover Herb Stratum (Plot size: ) 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. = Total Cover Woody Vine Stratum (Plot size: ) 1. 2. = Total Cover % Bare Ground in Herb Stratum Dominance Test worksheet: Number of Dominant Species That Are OBL, FACW, or FAC: (A) Total Number of Dominant Species Across All Strata: (B) Percent of Dominant Species That Are OBL, FACW, or FAC: (A/B) Prevalence Index worksheet: Total % Cover of: Multiply by: OBL species x 1 = FACW species x 2 = FAC species x 3 = FACU species x 4 = UPL species x 5 = Column Totals: (A) (B) Prevalence Index = B/A = Hydrophytic Vegetation Indicators: Rapid Test for Hydrophytic Vegetation Dominance Test is >50% Prevalence Index is ≤3.01 Morphological Adaptations1 (Provide supporting data in Remarks or on a separate sheet) Wetland Non-Vascular Plants1 Problematic Hydrophytic Vegetation1 (Explain) 1Indicators of hydric soil and wetland hydrology must be present, unless disturbed or problematic. Hydrophytic Vegetation Present? Yes No Remarks: Senza Lakeview Renton/King 4/1 iCap Equity, LLC WA S2 SB. JL 32, 24, 5 hillslope concaver <5 LRR A 47.527110 -122.202964 Alderwood gravelly sandy loam 8 to 15 % and Indianola loamy sand 5 to 15% slopes None 4 4 4 4 4 Precipitation levels are at 150% of normal for the water year. Thuja plicata 30 Y Fac Alnus rubra 20 Y Fac 50 Rubus armeniacus 80 Y FacU Salix scouleriana 20 Y Fac 100 3 4 75 0 0 0 0 0 0 0 4 4 US Army Corps of Engineers Western Mountains, Valleys, and Coast – Version 2.0 SOIL Sampling Point: 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 1Type: C=Concentration, D=Depletion, RM=Reduced Matrix, CS=Covered or Coated Sand Grains. 2Location: 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) 2 cm 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) 3Indicators of hydrophytic vegetation and Sandy Mucky Mineral (S1) Depleted Dark Surface (F7) wetland hydrology must be present, Sandy Gleyed Matrix (S4) Redox Depressions (F8) unless disturbed or problematic. Restrictive Layer (if present): Type:________________________________ Depth (inches):________________________ Hydric Soil Present? Yes No Remarks: HYDROLOGY 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 (B9) (except MLRA Water-Stained Leaves (B9) (MLRA 1, 2, High Water Table (A2) 1, 2, 4A, and 4B) 4A, and 4B) 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 (D7) Sparsely Vegetated Concave Surface (B8) Field Observations: Surface Water Present? Yes No Depth (inches): Water Table Present? Yes No Depth (inches): Saturation Present? Yes No Depth (inches): (includes capillary fringe) Wetland Hydrology Present? Yes No Describe Recorded Data (stream gauge, monitoring well, aerial photos, previous inspections), if available: Remarks: S2 0-12"10YR 2/2 90 sil 12-18+"110YR 4/3 90 10YR 4/6 5 C M sl 4 4 4 4 4 Soils were moist at the time of investigation even with higher than normal precipitation for the water year. Site Planning Civil Engineering Project Management Land Development Consulting FISH PASSAGE SCREEN LETTER WETLAND RESOURCES, INC. (APRIL 15, 2016) April 15, 2016 iCAP Equity LLC Attn: Barbara Rodgers 10900 NE 8th Street, #1000 Bellevue, WA 98004 RE: “On Hold” Notice for Senza Lakeview Preliminary Plat, LUA16- 000165, ECF, PP, SM Introduction Wetland Resources, Inc. was hired to respond to a recent review comment letter (On Hold Notice, dated April 5th, 2016) sent by City of Renton Planning Staff (Clark Close) to Jamie Schroeder (CPH Consultants). The “on hold” letter asks the applicant to respond to Washington Department of Fish and Wildlife comments made as part of their review of the SEPA checklist prepared for this project. WDFW made two substantive comments, which are paraphrased as follows: • Confirm that the outfall meets WAC 222-660-260 rules for the protection of fish life. • Locate the outfall above the ordinary high water mark for Lake Washington or outfit with a device to prevent entry of fish. Background Information The stormwater plan for the Senza plat ties in with the existing storm system upstream of the confluence with Lake Washington. Flows from the Senza property will enter an open channel on the east side of Lake Washington Blvd N and travel northeast to the intersection of N 40th street and Lake Washington Blvd N. The channel enters a catch basin and flows subsurface to the confluence with Lake Washington, located in the vicinity of Tract 051850TR-A. The outfall is an 30-inch-diameter ductile iron pipe that was constructed in 2007 as part of the Barbee Mill subdivision, and appears to be part of the municipal storm system. Field Investigation On April 12, 2016, Wetland Resources, Inc. visited the location where the existing outfall meets Lake Washington. The purpose of the site visit was to determine the ordinary high water mark (OHWM) of Lake Washington relative to the outfall pipe that will convey flows from the project site. If the invert elevation of the pipe is lower than the elevation of the OHWM, then a fish exclusion device would be necessary. 2 The OHWM was delineated using the methodology described in the Washington Department of Ecology best available science document titled. Determining the Ordinary High Water Mark on Streams in Washington State (Second Review Draft). The report was published in 2010 by Department of Ecology staff members Patricia Olson and Erik Stockdale. The ordinary high water mark of Lake Washington was determined in the field based on comparison with hydrograph data for Lake Washington, and using field indicators. Findings Based on OHWM delineation, the invert elevation of the pipe is lower than the ordinary high water mark (OHWM) of Lake Washington. Therefore the pipe is currently fish-passable, and will require a fish exclusion device in accordance with WDFW standards. Figure 1: Facing Northwest Towards the Stormwater Outfall Pipe 3 WAC 222-66-260 Compliance WAC 222-66-260 regulates outfalls when scouring or bank erosion would negatively impact fish habitat. It also requests that applicants consider tying into existing municipal storm water lines to avoid multiple storm water discharge points. Riprap was installed at the outfall location during original construction, to limit bank erosion. Furthermore, the applicant is proposing to tie into the existing municipal storm system. This project appears to comply with the standards set forth in WAC 222-66-260. Fish Exclusion Device Recent correspondence between WRI staff and Christa Heller (WDFW Habitat Biologist) indicates that an appropriate exclusion device could be either a screen at the outfall, a tideflex duckbill valve, or a tidegate. The applicant proposes to install a fish exclusion device at the outfall to Lake Washington. The final design for the exclusion device has not yet been determined, but will be designed in accordance with standards set forth in the WDFW document Fish Protection Screen Guidelines for Washington State (written by Bates and Nordlund, 2001). Conclusion The outfall currently meets the standards set forth in WAC 222-60-260. No additional protection from bank erosion is proposed. A fish exclusion device will be installed at the outfall to Lake Washington. Should you have any questions or concerns, please feel free to call the office at (425) 337-3174. Wetland Resources, Inc. Niels Pedersen Senior Ecologist Site Planning Civil Engineering Project Management Land Development Consulting ILLUMINATION CALCULATIONS TENW (DECEMBER 14, 2016) SENZA LAKEVIEW ILLUMINATIONLINE LOSS CALCULATIONSILLUM AILLUM A240Service VoltageA L RVd=2ALRCircuit SegmentConductor Size (#)(Watts) Load on SegmentLoad on Segment (AMPS) Length (Ft)Resitance (ohms / Ft)Voltage Drop (Volts) ∑ Voltage Drop (Volts)SVC to JB 8 379 1.90 10 0.000809 0.03 0.03JB to JB-L1 8 379 1.90 35 0.000809 0.11 0.14JB-L1 to JB-L2 8 288 1.44 60 0.000809 0.14 0.28JB-L2 to JB-L3 8 240 1.20 65 0.000809 0.13 0.40JB-L3 to JB-L4 8 192 0.96 65 0.000809 0.10 0.50JB-L4 to JB-L5 8 144 0.72 65 0.000809 0.08 0.58JB-L5 to JB-L6 8 96 0.48 65 0.000809 0.05 0.63JB-L6 to LUM-L68480.24250.0008090.010.64%Voltage Drop=0.27∑ of Voltage Drop=0.65% Max Page 112/15/2016 SENZA LAKEVIEW ILLUMINATIONLINE LOSS CALCULATIONSILLUM BILLUM B240Service VoltageA L RVd=2ALRCircuit SegmentConductor Size (#)(Watts) Load on SegmentLoad on Segment (AMPS) Length (Ft)Resitance (ohms / Ft)Voltage Drop (Volts) ∑ Voltage Drop (Volts)SVC to JB 8 836 4.18 10 0.000809 0.07 0.07JB to JB-L7 8 836 4.18 445 0.000809 3.01 3.08JB-L7 to JB-L8 8 792 3.96 75 0.000809 0.48 3.56JB-L8 to JB-L9 8 748 3.74 65 0.000809 0.39 3.95JB-L9 to JB-L10 8 484 2.42 80 0.000809 0.31 4.26JB-L10 to JB-L11 8 308 1.54 80 0.000809 0.20 4.46JB-L11 to JB-L12 8 264 1.32 80 0.000809 0.17 4.63JB-L12 to JB-L13 8 220 1.10 80 0.000809 0.14 4.78JB-L13 to JB-L14 8 176 0.88 25 0.000809 0.04 4.81JB-L14 to JB-L15 8 132 0.66 95 0.000809 0.10 4.91JB-L15 to JB-L16 8 88 0.44 90 0.000809 0.06 4.98JB-L16 to JB-L17 8 44 0.22 85 0.000809 0.03 5.01JB-L17 to LUM-L178440.22250.0008090.015.02%Voltage Drop=2.09∑ of Voltage Drop=5.05% MaxPage 212/15/2016 Site Planning Civil Engineering Project Management Land Development Consulting TRAFFIC REPORT TENW (DECEMBER 14, 2016) TENW Transportation Engineering NorthWest Transportation Planning | Design | Traffic Impact & Operations 11400 SE 8th Street, Suite 200, Bellevue, WA 98004 | Office (425) 889-6747 MEMORANDUM DATE: February 18, 2016 TO: Clark Close City of Renton FROM: Jeff Schramm TENW SUBJECT: Trip Generation and Traffic Assessment for the proposed Kennydale Residential TENW Project #5119 This memorandum documents the traffic assessment conducted for the proposed 17-unit Kennydale Residential project including a project description, trip generation estimate, project trip distribution, and impact fee calculation. Project Description The proposed Kennydale residential project site is located east of Lake Washington Boulevard N, west of Park Avenue N, and south of NE 40th Street in Renton as shown in the Attachment A site vicinity. The project proposes 17 single-family detached dwelling units on a site that is currently occupied by three single-family homes, all of which would be removed. Vehicular access to the site would be provided via a new proposed residential road on NE 40th Street. Full project buildout is expected in 2017. A preliminary site plan is provided in Attachment B. Trip Generation The trip generation estimate for the proposed Kennydale Residential project was based on trip rates and equations published in the Institute of Transportation Engineers (ITE) Trip Generation Manual, 9th edition for Land Use Code (LUC) 210 (Single-Family Detached Housing). The weekday daily, AM and PM peak hour trip generation estimates associated with the proposed project are summarized in Table 1. Table 1 Trip Generation Summary – Kennydale Residential Net New Trips Generated Time Period In Out Total Weekday Daily 82 82 164 Weekday AM Peak Hour 3 8 11 Weekday PM Peak Hour 10 7 17 Traffic Assessment – Kennydale Residential TENW February 18, 2016 Page 2 As shown in Table 1, the proposed Kennydale Residential project is anticipated to generate 164 net new trips per weekday, with 11 of those trips generated during the AM peak hour (3 in, 8 out) and 17 during the PM peak hour (10 in, 7 out). Detailed trip generation calculations are included in Attachment C. Trip Distribution The estimated distribution of project traffic was based on existing travel patterns. The weekday AM and PM peak hour net new project-generated trips were generally distributed as follows in the site vicinity: · 50 percent to/from the north on Lake Washington Boulevard N · 40 percent to/from the south on Park Avenue N · 10 percent to/from the south on Lake Washington Boulevard N Attachment D provides a graphic illustration of the estimated trip distribution patterns for the proposed project. City of Renton Impact Fees To mitigate long-term traffic impacts, the City of Renton requires payment of a traffic impact fee. The CityÊs currently adopted impact fee rate is $2,856.89 per single-family lot. Based on 14 net new dwelling units (17 proposed less 3 existing), the resulting impact fee would be $39,996.46 (14 net new units X $2,856.89/unit). The CityÊs impact fee rate is subject to change. If you have any questions regarding the information presented in this Traffic Impact Analysis, please contact me at 425-250-0581 or schramm@tenw.com. cc: Jamie Schroeder, P.E – CPH Consultants Jeff Haynie, P.E – TENW Principal Attachments: A. Site Vicinity Map B. Preliminary Site Plan C. Trip Generation Calculations D. Project Trip Distribution Traffic Assessment – Kennydale Residential ATTACHMENT A Site Vicinity Project Site Attachment A: Project Site Vicinity N NOT TO SCALE Traffic Assessment – Kennydale Residential ATTACHMENT B Preliminary Site Plan Attachment B: Preliminary Site Plan N NOT TO SCALE Traffic Assessment – Kennydale Residential ATTACHMENT C Trip Generation Calculations DAILY ITE Land Use Area Units1 LUC2 In Out In Out Total Proposed Use: Single-Family 17 DU 210 eqn 50%50%103 103 206 Less Existing Use: Single-Family 3 DU 210 eqn 50%50%-21 -21 -42 NET NEW DAILY TRIP GENERATION =82 82 164 AM PEAK HOUR ITE Land Use Area Units1 LUC2 In Out In Out Total Proposed Use: Single-Family 17 DU 210 0.75 25%75%3 10 13 Less Existing Use: Single-Family 3 DU 210 0.75 25%75%0 -2 -2 NET NEW AM PEAK HOUR TRIP GENERATION =3 8 11 PM PEAK HOUR ITE Land Use Area Units1 LUC2 In Out In Out Total Proposed Use: Single-Family 17 DU 210 eqn 63%37%13 8 21 Less Existing Use: Single-Family 3 DU 210 eqn 63%37%-3 -1 -4 NET NEW PM PEAK HOUR TRIP GENERATION =10 7 17 Notes: 1. DU = Dwelling Units. 2. Institute of Transportation Engineers (ITE) Trip Generation manual 9th edition land use code. 3. Trip rate equations and directional split based on ITE Trip Generation manual 9th edition. Kennydale Residential Trip Rate3 Directional Split3 Trips Generated Trip Rate3 Directional Split3 Trips Generated Trip Rate3 Directional Split3 Trips Generated Kennydale Residential TENW Project No. 5119 2/15/2016 Traffic Assessment – Kennydale Residential ATTACHMENT D Project Trip Distribution Attachment D: Project Trip Distribution N NOT TO SCALE SITE 50% 10%40% Site Planning Civil Engineering Project Management Land Development Consulting ARBORIST REPORT/TREE PLAN AMERICAN FOREST MANAGEMENT (FEBRUARY 9, 2016) ARBORIST REPORT/TREE PLAN FOR KENNYDALE PROJECT PARCELS 3342700415, --420, --425, --427 RENTON, WA February 9, 2016 American Forest Management 2/9/2016 Table of Contents 1. Introduction .............................................................................................................. 1 2. Description ............................................................................................................... 1 3. Methodology ............................................................................................................ 1 4. Observations ........................................................................................................... 2 5. Discussion ............................................................................................................... 2 6. Tree Protection Measures ........................................................................................ 3 7. Tree Replacement ................................................................................................... 3 Appendix Site/Tree Photos – pages 5 – 8 Tree Summary Tables - attached Tree Conditions Map - attached Tree Protection Plan – attached Tree retention Worksheet - attached General Tree Protection Fencing Detail - attached Kennydale Arborist Report Page 1 American Forest Management 2/9/2016 1. Introduction American Forest Management, Inc. was contacted by Jamie Schroeder of CPH Consultants, and was asked to compile an ‘Arborist Report’ for four parcels located within the City of Renton. The proposed subdivision encompasses parcels 3342700415, --420, --425, --427. Our assignment is to prepare a written report on present tree conditions, which is to be filed with the preliminary permit application. This report encompasses all of the criteria set forth under City of Renton code section 4-4-130. The tree retention requirement is 30% of significant trees. Date of Field Examination: August 27th, 2015 2. Description 40 significant trees were identified and assessed on the property. These are comprised of a mix of native species and planted ornamental species. A numbered aluminum tag was placed on the lower trunks of the subject trees by the surveying crew. These numbers were used for this assessment. Tree tag numbers correspond with the numbers on the Tree Summary Tables and attached maps. There are only a few issues with neighboring trees. The property is bounded on three sides by roads. There are only two neighboring tree issues on the south property lines which are not anticipated to be concerning. 3. Methodology Each tree in this report was visited. Tree diameters were measured by tape. The tree heights were measured using a Spiegel Relaskop. Each tree was visually examined for defects and vigor. The tree assessment procedure involves the examination of many factors:  The crown of the tree is examined for current vigor. This is comprised of inspecting the crown (foliage, buds and branches) for color, density, form, and annual shoot growth, limb dieback and disease. The percentage of live crown is estimated for coniferous species only and scored appropriately.  The bole or main stem of the tree is inspected for decay, which includes cavities, wounds, fruiting bodies of decay (conks or mushrooms), seams, insects, bleeding, callus development, broken or dead tops, structural defects and unnatural leans. Structural defects include crooks, forks with V-shaped crotches, multiple attachments, and excessive sweep.  The root collar and roots are inspected for the presence of decay, insects and/or damage, as well as if they have been injured, undermined or exposed, or original grade has been altered. Based on these factors a determination of viability is made. Trees considered ‘non-viable’ are trees that are in poor condition due to disease, extensive decay and/or cumulative structural defects, which exacerbate failure potential. A ‘viable’ tree is a tree found to be in good health, in a sound condition with minimal defects and is suitable for its location. Also, it will be wind firm if isolated or left as part of a grouping or grove of trees. A ‘borderline’ viable tree is a tree where its viability is in question. These are trees that are beginning to display symptoms of decline due to age and or species related problems. Borderline trees are not expected to positively contribute to the landscape for the long-term and are not recommended for retention. The attached Tree Conditions Map indicates the viability of the subject trees. Kennydale Arborist Report Page 2 American Forest Management 2/9/2016 4. Observations The subject trees are comprised of a mix of native and planted species. Native species are comprised of red alder, Scouler’s willow, pacific madrone, Douglas-fir and black cottonwood. Planted species include redwood, Ponderosa pine, fruit trees, Colorado blue spruce, dogwood and Norway maple. Five of the 40 assessed trees are in poor condition and considered non-viable. These are described as follows: Tree #7866 is an over-mature apple variety. The lower trunk is extensively decayed. The subject will likely collapse within the next few years. Tree #7614 is another over-mature apple variety. Its productive life span is compromised by decay and disease. Tree #7217 is an over-mature purple-leaf plum or cherry plum, Prunus cerasifera. It is approximately 98% dead. The trunk and large laterals are cracked. Its structure is compromised by extensive internal decay. The subject will likely collapse within the next few years. See picture below. Tree #7771 is an over-mature red alder. It also has major basal and internal decay/rot. See picture below. The subject is high risk with a high potential for complete trunk failure. Tree #7777 is a semi-mature cluster of Scouler’s willow. Many of the stems are in premature decline. Most have developed advanced decay in the lower stems. Productive life span is likely less than five years. Additionally, five of the subject trees are considered ‘borderline’ viable, which are not recommended for retention. These are native pioneer hardwood species of black cottonwood, Scouler’s willow and red alder all with significant defects. These are not expected to positively contribute to the landscape for the next decade. 5. Discussion Of the 40 trees assessed, 30 are in a sound and healthy condition, and considered viable. Significant trees are scattered across the site. Five trees are proposed for retention/protection. These are primarily found on the south perimeter of the site. In order to properly protect retained trees, existing grades shall be maintained around them to the fullest extent possible. After review of the proposed design, the subject trees selected for retention can be successfully preserved in good condition, so long as the proper tree protection measures are taken. The drip-lines (farthest reaching branches) for the subject trees can be found on the tree summary tables at the back of this report. These have also been delineated on a copy of the development plan for trees proposed for retention. The information plotted on the attached plan may need to be transferred to a final tree retention/protection plan to meet City submittal requirements. The trees that are to be removed shall be shown “X’d” out on the final plan. The Limits of Disturbance (LOD) measurements can also be found on the tree summary table. This is the recommended distance of the closest impact (soil excavation or fill) to the trunk face. These should be referenced when determining tree retention feasibility. The LOD measurements are based on species, age, condition, drip-line, prior improvements, proposed impacts and the anticipated cumulative impacts to the entire root zone. Tree Protection fencing shall be initially located a few feet beyond the drip-line edge of retained trees per the attached plan, and only moved back to the LOD when work is authorized and ready to commence. The proposed water main line northwest of the large redwood tree #7819 is approximately 18’ from the trunk face. The recommended LOD is 16’. Any roots greater than 2” in diameter encountered during utility work shall be pruned clean to sound tissue prior to backfilling. Kennydale Arborist Report Page 3 American Forest Management 2/9/2016 The new sidewalk adjacent to Lake WA Blvd will be designed to afford Tree #7520 more space. The proposed sidewalk is outside of the recommended LOD. Impacts to the subject tree related to sidewalk improvements are not expected to be significant. There are no major conflicts concerning neighboring trees. The property is bounded on three sides by roads. Subject trees #7790 and #109 situated on the south perimeter are well positioned for retention. For Tree #7790, maintain existing grades within 8’ of the property line and 5’ for Tree #109. Keep retaining walls outside of tree protection zones. Finished landscaping work within the drip-lines of retained trees shall maintain existing grades and not disturb fine root mass at the ground surface. Finish landscape with beauty bark or new lawn on top of existing grade. Add no more than 2” to 4” of mulch/beauty bark or 2” of composted soil to establish new lawn. Raising the grade more than a few inches will have adverse impacts on fine roots by cutting off oxygen causing suffocation. 6. Tree Protection Measures The following general guidelines are recommended to ensure that the designated space set aside for the preserved trees are protected and construction impacts are kept to a minimum. 1. Tree protection fencing should be erected around retained trees and positioned just beyond the drip-line edge prior to moving any heavy equipment on site. Doing this will set clearing limits and avoid compaction of soils within root zones of retained trees. 2. Any existing infrastructure to be removed within the drip-line or tree protection zone shall be removed by hand or utilizing a tracked mini-excavator. 3. Excavation limits should be laid out in paint on the ground to avoid over excavating. 4. Excavations within the drip-lines shall be monitored by a qualified tree professional so necessary precautions can be taken to decrease impacts to tree parts. A qualified tree professional shall monitor excavations when work is required and allowed within the “limits of disturbance”. 5. To establish sub grade for foundations, curbs and pavement sections near the trees, soil should be removed parallel to the roots and not at 90 degree angles to avoid breaking and tearing roots that lead back to the trunk within the drip-line. Any roots damaged during these excavations should be exposed to sound tissue and cut cleanly with a saw. Cutting tools should be sterilized with alcohol. 6. Areas excavated within the drip-line of retained trees should be thoroughly irrigated weekly during dry periods. 7. Preparations for final landscaping shall be accomplished by hand within the drip-lines of retained trees. Large equipment shall be kept outside of the tree protection zones at all times. Simply finish landscape within 10’ of retained trees with a 2” to 4” layer of organic mulch. 7. Tree Replacement Supplemental trees will likely be necessary to meet the retention requirement, given the low potential for successful tree retention. The tree retention calculation is based on 26 significant trees, not including high-risk or danger trees (6), or trees within proposed public streets (8). The retention requirement for the site is 30%, therefore, a total of 8 trees are required for retention per code. The following replacement requirements are necessary when retained/protected trees do not meet the minimum requirement per 4-4-130 H. Performance Standards for Land Development/Building Permits: e. Replacement Requirements: As an alternative to retaining trees, the Administrator may authorize the planting of replacement trees on the site if it can be demonstrated to the Administrator’s satisfaction that an insufficient number of trees can be retained. Kennydale Arborist Report Page 4 American Forest Management 2/9/2016 i. Replacement Ratio: When the required number of protected trees cannot be retained, replacement trees, with at least a two-inch (2") caliper or an evergreen at least six feet (6') tall, shall be planted at a rate of twelve (12) caliper inches of new trees to replace each protected tree removed. Up to fifty percent (50%) of trees required pursuant to RMC 4-4-070, Landscaping, may contribute to replacement trees. The City may require a surety or bond to ensure the survival of replacement trees. The proposal is to retain or protect five significant trees, therefore three will need to be replaced per the above. This will require the supplemental planting of 18 – 2” caliper replacement trees for a total replacement of 36 caliper inches (3 X 12). Nine of these will be satisfied by landscaping requirements so an additional nine will be required above the minimum density requirement of two trees per lot. The Tree Retention Worksheet is attached. New tree plantings shall be given the appropriate space for the species and their growing characteristics. Confer with the City’s Urban Forester for appropriate replacement species. For planting and maintenance specifications, refer to municipal code 4-4-070 Landscaping. There is no warranty suggested for any of the trees subject to this report. Weather, latent tree conditions, and future man-caused activities could cause physiologic changes and deteriorating tree condition. Over time, deteriorating tree conditions may appear and there may be conditions, which are not now visible which, could cause tree failure. This report or the verbal comments made at the site in no way warrant the structural stability or long term condition of any tree, but represent my opinion based on the observations made. Nearly all trees in any condition standing within reach of improvements or human use areas represent hazards that could lead to damage or injury. Please call if you have any questions or I can be of further assistance. Sincerely, Bob Layton ISA Certified Arborist #PN-2714A Tree Risk Assessment Qualified (TRAQ) Kennydale Arborist Report Page 5 American Forest Management 2/9/2016 Tree #7771 – Non-viable Tree #7217 – Non-viable Kennydale Arborist Report Page 6 American Forest Management 2/9/2016 Tree #7785 (left), neighboring tree #7790 (right) Neighboring Tree #7172 Kennydale Arborist Report Page 7 American Forest Management 2/9/2016 Southwest portion of property Overview of property looking west Kennydale Arborist Report Page 8 American Forest Management 2/9/2016 Large girdling root on tree 7962 Tree Summary Table American Forest Management, Inc. For:Kennydale Project Date:8/27/2015 Renton Inspector:Layton Native/ Planted/ Tree/Tag #Species VolunteerDBH Height Condition Viability Comments N S E W 7785 burgundy Norway maple P 35 63 27/16 25/NA 25/15 24/15 FAIR-GOOD VIABLE LARGE SPREADING CROWN 7217 purple-leaf plum P 16 22 X X X X POOR NON-VIABLE 95% DEAD, CRACKED 7696 Pacific madrone N 12 22 14/10 5/10 8/8 13/10 FAIR-GOOD VIABLE YOUNG, NATURAL LEAN 101 Pacific madrone N 11 24 12/8 10/8 10/8 8/8 GOOD VIABLE YOUNG 102 big leaf maple N 10 32 14/8 12/8 12/8 12/8 FAIR VIABLE YOUNG, FORKED TOP 7962 black cottonwood N 17 52 18/14 16/14 13/10 15/12 FAIR-POOR BORDERLINE LARGE GIRDLING ROOT, CROOKED TRUNK 7520 western red cedar N 22 46 14/12 18/16 14/12 18/14 GOOD VIABLE NO CONCERNS 103 European white birch V 11 44 10/8 12/8 8/8 10/8 FAIR VIABLE TYPICAL 7783 Douglas-fir P 15 41 14/10 14/10 14/10 12/10 GOOD VIABLE YOUNG, FULL CROWN 7784 Douglas-fir P 15 45 14/10 14/10 8/10 12/10 GOOD VIABLE YOUNG, FULL CROWN 7772 red alder N 15 48 14/10 10/10 14/10 14/10 FAIR-POOR BORDERLINE LARGE CAVITY, SIGNIFCANT DECAY 7771 red alder N 23 50 X X X X POOR NON-VIABLE EXTENSIVE TRUNK ROT, DYING TOP, HIGH RISK 7780 Scouler's willow N 14 43 12/10 12/10 8/8 10/8 FAIR VIABLE TYPICAL 7778 black cottonwood N 11 43 6/8 6/8 6/8 8/8 FAIR VIABLE YOUNG, POOR FORM 7777 Scouler's willow N 6"-8"40 X X X X POOR NON-VIABLE CLUSTER, DECAY, DECLINE 7782 western red cedar N 15 40 10/6 12/10 10/10 10/10 FAIR VIABLE BROKEN TOP, GOOD COLOR 7770 Colorado blue spruce P 12 28 8/6 10/10 8/8 8/8 FAIR-GOOD VIABLE NATURAL LEAN SOUTH, TYPICAL 7765 red alder N 13,11 48 16/10 8/10 16/10 12/10 FAIR-POOR BORDERLINE FORKED AT ROOT CROWN, WEAKLY ATTACHED 104 weeping willow P 12 33 16/10 10/10 16/10 12/10 FAIR VIABLE INJURED TRUNK, OKAY FOR NOW 7766 Douglas-fir N 21 56 16/14 18/16 14/12 16/14 GOOD VIABLE YOUNG TO SEMI-MATURE 105 Italian plum V 6"-12"32 12/10 16/10 14/10 16/12 FAIR-POOR BORDERLINE HEAVY LEANS, SOME DECLINE, SUPPRESSED 7536 redwood P 35,38 86 20/16 23/18 24/18 20/18 GOOD VIABLE LARGE SPECIMENS 7866 apple P 16 30 X X X X POOR NON-VIABLE EXTENSIVE ROT, MATURE 7865 apple P 12,12 30 10/10 12/10 8/10 12/10 FAIR VIABLE TYPICAL 7535 Ponderosa pine P 28 82 16/12 25/16 12/12 12/12 FAIR VIABLE FORKED TOP, MODERATE RISK 7534 Ponderosa pine P 19 76 13/10 14/12 8/10 10/10 FAIR VIABLE FORKED TOP, MODERATE RISK 106 pear P 10,9 14 6/8 10/8 8/8 10/8 FAIR VIABLE HEAVILY PRUNED 7532 Ponderosa pine P 22 72 12/14 12/14 12/12 10/12 FAIR VIABLE TYPICAL 7531 European white birch V 13 56 10/10 14/10 10/10 8/10 FAIR VIABLE TYPICAL Drip-Line measurements from face of trunk Drip-Line (feet) Tree Summary Table American Forest Management, Inc. For:Kennydale Project Date:8/27/2015 Renton Inspector:Layton Native/ Planted/ Tree/Tag #Species VolunteerDBH Height Condition Viability Comments N S E W 7530 Ponderosa pine P 34 82 18/14 24/16 12/14 16/14 GOOD VIABLE NO CONCERNS 7529 Colorado blue spruce P 15 34 12/12 10/12 14/12 10/12 GOOD VIABLE YOUNG 7528 pacific madrone N 12 25 10/10 16/12 8/10 12/10 FAIR VIABLE TYPICAL 7614 apple P 16 18 X X X X POOR NON-VIABLE OVER-MATURE 107 noble fir P 10 30 6/7 5/7 5/7 6/7 FAIR VIABLE LARGE FROST CRACK 108 dogwood P 10 18 8/8 10/8 10/8 8/8 FAIR VIABLE TOPPED IN PAST 7657 apple P 12 22 8/8 12/NA 10/8 13/10 FAIR VIABLE HEAVILY PRUNED 7819 redwood P 56 73 28/18 NA 26/18 22/16 GOOD VIABLE TYPICAL 7820 European white birch V 9,11 51 16/8 NA 10/8 8/10 FAIR VIABLE TYPICAL 7821 Colorado blue spruce P 25 70 14/12 NA 12/10 14/14 GOOD VIABLE NO CONCERNS 110 Scouler's willow N 4"-7"30 18/12 16/12 14/10 12/12 FAIR BORDERLINE LARGE CLUSTER, SHORT-LIVED 7172 big leaf maple N 16 40 13/8 NA 19/12 15/12 FAIR VIABLE MULTIPLE TRUNKS 7790 black locust V 15,10,12 68 10/8 NA 10/10 16/12 FAIR VIABLE MATURE 109 Japanese maple P 8 24 10/8 NA 8/8 12/10 FAIR VIABLE TYPICAL Drip-Line measurements from face of trunk Drip-Line (feet) NEIGHBORING TREES 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 PRELIMINARY PLAT and SHORELINE PERMIT- 1 BEFORE THE HEARING EXAMINER FOR THE CITY OF RENTON RE: Senza Lakeview Preliminary Plat Preliminary Plat LUA16-000165, PP, SM ))))))))) FINAL DECISION SUMMARY The applicant requests preliminary plat and shoreline substantial development permit approval for a 17-lot residential subdivision located at 3907 Park Ave N. The preliminary plat and shoreline permit are approved with conditions. TESTIMONY Clark Close, City of Renton senior planner, summarized the staff report. The applicant is requesting a preliminary plat and shoreline substantial development permit in support of a 17-lot residential subdivision. The site was annexed in 1904. The neighborhood is Kennydale. The zoning is R-6, Residential Medium Density. The zoning was updated in June 2015. The site is currently vacant. There are 40 significant trees on site. The applicant will retain 5 of the 26 required trees. There is a slope on the property. There are no critical areas on the project site. There are no wetlands or streams on or near the site. There are no unstable soils. The lots meet minimum lot size and density requirements. Lots access Park Avenue N and N. 40th street either directly or indirectly from an internal hammerhead. The site directly discharges to Lake Washington. Environmental mitigation measures are required to prevent fish from entering the outfall pipe. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 PRELIMINARY PLAT and SHORELINE PERMIT- 2 The City received several public comments (Ex. 21-24). The City issued a SEPA Mitigated Determination of Non-Significance with three mitigation measures. The proposal is compliant with the Comprehensive Plan. The proposal complies within the Shoreline Master Plan for Lake Washington Reach D. The proposal will comply as conditioned with the zoning code and applicable development standards. Staff recommends approval with conditions. Mr. Close stated Condition of Approval #4 regarding protection of the western red cedar tree requires a note on the plat that prevents removal of the tree and deviates the route of the sidewalk to retain the tree. Condition of Approval #7 is a response to public comments. It requires a solid fence for screening for the property owners to the south. Condition of Approval #9 requires a connector path from Lake Washington Blvd. to the community’s open space tract. Condition of Approval #10 is also in response to public comments. The intent is to discourage unwanted trips to the private drive during construction of the project. Condition of Approval #11 requires orientation of the houses to Lake Washington Blvd. where applicable. In response to the examiner Brianne Bannwarth, Development Engineering Manager, stated the adopted stormwater code allows off-site release of stormwater without additional flow control within ½ mile of Lake Washington Blvd. The project owner asked for reconsideration of some of the conditions of approval. He had a concern about Condition No. 11, which required the homes facing Lake Washington to front Lake Washington Boulevard The design of the homes was going to include daylight basements. Creating front facades along this area would be very challenging. They would require stairs to get in from the street. They would already plan articulation along that area to take advantage of the views. It also changes the setbacks with respect to what is the front or rear yard. He suggested Condition #11 be stricken and replaced with a requirement to work with the City to create rear facades that provide the design articulation the City desires without the need to create front facades along Lake Washington Blvd. Mohammed Qaasim, neighbor, asked for clarification on Condition #11. He simply couldn’t hear the testimony. He also asked about the construction mitigation noise. He lives adjacent to the project. There was a lot of dust from the demolition of the two houses. He doesn’t want to experience a year of dust conditions. He asked about dust and noise mitigation. Scott Petett, neighbor, asked about sidewalks along 40th and a crosswalk. Mr. Close stated there is no proposal to add a crosswalk on 40th Avenue and Lake Washington Blvd. There are not any in the immediate vicinity. Mr. Close stated the City would review it. Mr. Petett also asked about the path from the community open space to Lake Washington Blvd. Mr. Close stated the path will not go through the lots. It will provide connection from the Blvd. to the community open space. The open 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 PRELIMINARY PLAT and SHORELINE PERMIT- 3 space will be the property of the homeowners association (Condition of Approval #12). Staff recommends non-native plant removal (Condition of Approval #5). No other improvements are recommended. Mr. Petett asked about the rails to trails conversion on Lake Washington. In response, Vanessa Dolby stated there is a draft environmental impact statement from King County. There is no access point planned yet, but there will be one in another planned mixed use project close by. Mr. Petett also asked about street trees and building heights. Mr. Close described the trees and building heights. Mr. Petett asked about the final finished grade. The applicant stated the goal is to balance the site for grading purposes to minimize costs for fill/grade and retaining walls. Mr. Petett stated he was concerned about Lots 4-6. In response to the examiner, Ms. Bannwarth stated the City’s policy with respect to crosswalks is to minimize them on arterials with lots of traffic. They prefer to add crosswalks in areas that have ADA compliant sidewalks on both sides of the road. This is not the case here. There will be a crosswalk north of the site that has ADA compliant ramps and facilities on both sides. There will likely not be one here. Ms. Bannwarth stated there are no plans that would create sidewalks on the north side of Lake Washington Blvd. Mr. Close discussed the roadway profiles for the roads in the vicinity of the project. Staff are willing to support modifications to the roadway widths within the project to allow for sidewalks. With respect to dust control, Mr. Close stated a single-family demolition permit has less oversight than a clear and grade permit as required for this project. There will be mitigation measures to control noise and dust. Ms. Bannwarth stated there are multiple permit requirements during the civil permitting stage to reduce dust. The City will be more actively paying attention to this issue now that they know about it. Mr. Close spoke to Condition #11. Mr. Close stated the applicant’s suggestion with respect to this condition is not acceptable to the City. Instead, he argued that there should be two front elevations, one along the access and one to Lake Washington Blvd. The applicant stated buildout is contingent on economic conditions. They are ready to move forward as soon as they civil permits are issued. He also stated two front elevations are an onerous condition. It is unreasonable. Mr. Close stated RMC 4-2-115 requires the design standard for frontages. EXHIBITS Exhibits 1-30 listed in the Exhibit List on Page 2 of the staff report, dated June 14, 2016, are admitted. In the addition, the following exhibits were admitted during the hearing on this matter: Exhibit 31: Staff PowerPoint Exhibit 32: COR Maps Exhibit 33: Google Maps 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 PRELIMINARY PLAT and SHORELINE PERMIT- 4 FINDINGS OF FACT Procedural: 1. Applicant. Jamie Schroeder, CPH Consultants. 2. Hearing. The hearing for the application was held on June 14, 2016 at noon in the City of Renton Council City Chambers. Substantive: 3. Project Description. The applicant requests preliminary plat and shoreline substantial development permit approval for a 17-lot residential subdivision located at 3907 Park Ave N. The project site is 3.83 acres in size. In addition to 17 residential lots, the applicant proposes a water quality tract and an open space tract. The proposed lots range in size from 7,000 sf to 9,531 sf with an average lot size of 7,470 sf. The plat would result in a net density of 5.3 du/ac. The project site is fronted by N 40th St to the north, Park Ave N to the east, and Lake Washington Blvd N to the west. Access to the site would be gained by a new public roadway (Road A) off of N 40th St. A shoreline substantial development permit is required because required frontage improvements along Lake Washington Blvd N are within 200 ft of Lake Washington. The site slopes generally east to west across the property at slopes ranging from 1-40% with a total fall of roughly 70 ft. The project site has or had three existing homes in various stages of being demolished. The applicant has proposed to retain five (5) of 40 significant trees onsite. 4. Surrounding Uses. The property is surrounded on all sides by single-family residences zoned at R-6. The homes to the west are on waterfront parcels on Lake Washington separated from the project site by Lake Washington Boulevard. 5. Adverse Impacts. There are no significant adverse impacts associated with the proposal. Pertinent impacts are addressed as follows: A. Compatibility. The applicant proposes single-family development in an area that is surrounded by single-family development at a density that is similar to existing development. There are no compatibility problems associated with the proposal. An issue of disagreement between the applicant and the City on aesthetic compatibility was staff recommended Condition No. 11, which requires the front facades of Lots 3-6 to face Lake Washington Boulevard. Design requirements can only be imposed when design standards are clear and unequivocal. See Anderson v. Issaquah, 70 Wn. App. 64 (1993). At the hearing staff noted that recommended Condition No. 11 is based upon RMC 4-2-115. It appears that staff was specifically referring to RMC 4-2-115( E)(3), which requires that “[f]ront doors shall face the street and be on the façade closest to the street”. “The street” in this requirement is not clear, i.e. which street? Given the ambiguity, it is fair to conclude that “the street” could be Road B, not Lake Washington Boulevard. In support of this conclusion, RMC 4-2-115(E)(3) further provides that the 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 PRELIMINARY PLAT and SHORELINE PERMIT- 5 front entrance must “allow for social interaction”. Creating a focal point for social interaction makes far more sense if it faces the persons residing within the Senza neighborhood, as opposed to those travelling past the neighborhood along Lake Washington Boulevard. RMC 4-2-115(E)(3) is ambiguous enough to be interpreted as requiring the front door to face either Road B or Lake Washington Boulevard. In the absence of any standards identifying which street is preferable, the applicant can choose which street applies. However, there is a trade-off. RMC 4-2-115(E)(3) further requires that the front doors be located “on the façade closest to the street.” The narrowness of Lots 3-5 appears to dictate that the garages of the homes be located closest to Road B, as depicted in the applicant’s tree retention plan, Ex. 5. If the applicant chooses to have its front doors facing Road B, the front doors will have to be located on the home facades closest to the street. Recommended Condition No. 11 will be modified accordingly for this decision. B. Critical Areas and Vegetation Removal. The project site has steep slopes and a landslide hazard area. The applicant submitted a geotechnical report that determined that the proposal would not increase the threat of landslide hazard to adjacent properties and that no setbacks were necessary from the steep slopes of the property. See Ex. 11. Beyond critical areas and the criteria applicable to the shoreline permit, the only code requirements for protection of wildlife and its habitat at the project site are the City’s tree retention standards. The City’s tree retention standards require the retention of 30% of the significant trees at the project site. The applicant’s arborist report identified 26 protected significant trees at the project site. The applicant proposes to retain 5 of the required 8 trees. As authorized by the City’s tree retention standards, the applicant proposes to replace the remaining three required trees with 52 new trees. Staff have determined that the applicant’s tree retention plan is consistent with City standards. C. Shoreline Ecological Function. The staff report concludes that the proposal will result in no net loss of ecological function. There being no evidence or indication to the contrary (given the nominal construction within shoreline jurisdiction) the staff conclusions are taken as verities. The only work within 200 feet of Lake Washington would be to construct minimal road widening and sidewalk improvements along project frontage of Lake Washington boulevard. The only other portion of the project within shoreline jurisdiction is at the southwest corner of the project site and is limited to an open space tract. The proposal would not have a direct impact to the shoreline because of pre-existing development, i.e. Lake Washington Boulevard N., an existing railroad tract and an existing row of waterfront homes. Cleared areas within the shoreline areas will be replanted, providing for an improvement of shoreline functions. Erosion and sediment controls implemented during construction would ensure no temporary construction impacts. 5. Adequacy of Infrastructure/Public Services. As conditioned, the project will be served by adequate/appropriate infrastructure and public services as follows: A. Water and Sewer Service. The site is served by the City of Renton for both water and sewer. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 PRELIMINARY PLAT and SHORELINE PERMIT- 6 B. Police and Fire Protection. Police and fire service would be provided by the City of Renton. Police and fire service staff have concluded they have sufficient resources to serve the proposal. Fire impact fees will be collected during building permit review to pay for proportionate share fire system improvements. C. Drainage. Preliminary drainage design conforms to the City’s stormwater standards as determined by Public Works staff. The applicant submitted a technical information report dated February 25, 2015, Ex. 12 that outlines its preliminary drainage design and documents compliance with City stormwater standards. The stormwater plan involves collecting water on-site for water quality treatment and then direct discharge to the 100- year floodplain of Lake Washington as authorized by City stormwater standards. The City’s stormwater standards, primarily adopted as the 2009 King County Surface Water Design Manual and City amendments thereto, assures that there will be no adverse impacts to surrounding properties caused by stormwater discharge resulting from the development. D. Parks/Open Space. It is anticipated that the proposed development would generate future demand on existing City parks and recreational facilities and programs. A Parks Impact Fee, based on new single family lots, will be required in order to mitigate the proposal’s potential impacts to City parks and recreational facilities and programs. Payment of the park impact fee will provide for adequate/appropriate park facilities. Beyond the park impact fee, the City does not require any specific open space for R-4 subdivisions. RMC 4-2-115 does require open space for developments zoned R-10 and R-14, but these requirements don’t extend to R-6 developments. Despite the absence of any specific requirements for open space, the applicant is proposing a 7,995 square foot open space tract at the southwest corner of the project site. Existing vegetation and one 22-inch caliper western red cedar is proposed to be retained within the tract. E. Streets. The proposal provides for adequate/appropriate streets. City Public Works staff have reviewed the proposal for conformance to City street standards and have found them to be satisfied. As outlined at page 21 of the staff report, a number of street frontage improvements along the project’s street frontage is required of the applicant. As noted in Finding of Fact No. 3, direct access will not be of off Lake Washington Boulevard N but rather will be accomplished through a connection to N 40th St. The applicant prepared a traffic study, Ex. 13, and public works staff concluded from this report that the proposal would not adversely affect the City’s street system and that the required payment of transportation impact fees would adequately mitigate all off-site traffic impacts. F. Parking. As determined by staff, sufficient area exists, on each lot, to accommodate off street parking for a minimum of two vehicles per dwelling unit as required by City code. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 PRELIMINARY PLAT and SHORELINE PERMIT- 7 G. Schools. The proposal will be served by adequate/appropriate school facilities. It is anticipated that the Renton School District can accommodate any additional students generated by this proposal at the following schools: Hazelwood Elementary School, McKnight Middle School and Hazen High School (Exhibit 20). Any new students attending the Renton schools would be bussed. The proposed project includes the installation of frontage improvements along the public street frontages, including sidewalks. The designated school bus stop is at the following intersections (at or near the project site): Lake Washington Blvd N/N 40th St, Park Ave N/N 40th St or Park Ave N/N 39th Pl. Therefore, there are safe walking routes to the school bus stops. A School Impact Fee, based on new single-family lots, will be required in order to mitigate the proposal’s potential impacts to the Renton School District. Conclusions of Law 1. Authority. RMC 4-7-020(C) and 4-7-050(D)(5) provide that the Hearing Examiner shall hold a hearing and issue a final decision on preliminary plat applications. Shoreline substantial development permits are classified by RMC 4-8-080(G) as Type II permits (subject to staff as opposed to hearing examiner review), but the shoreline permit of this case has been consolidated into the preliminary plat review process pursuant to RMC 4-8-080(C). 2. Zoning/Comprehensive Plan Designations. The subject property is zoned R-6 and has a comprehensive plan land use designation of Residential Medium Density (RMD). 3. Review Criteria. Chapter 4-7 RMC governs the criteria for subdivision review. The criteria for shoreline substantial development permits is set by RMC 4-9-190(B)(7), which requires compliance with all City of Renton Shoreline Master Program (“SMP”) use regulations and SMP policies. Applicable standards are quoted below in italics and applied through corresponding conclusions of law. Preliminary Plat RMC 4-7-080(B): A subdivision shall be consistent with the following principles of acceptability: 1. Legal Lots: Create legal building sites, which comply with all provisions of the City Zoning Code. 2. Access: Establish access to a public road for each segregated parcel. 3. Physical Characteristics: Have suitable physical characteristics. A proposed plat may be denied because of flood, inundation, or wetland conditions. Construction of protective improvements may be required as a condition of approval, and such improvements shall be noted on the final plat. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 PRELIMINARY PLAT and SHORELINE PERMIT- 8 4. Drainage: Make adequate provision for drainage ways, streets, alleys, other public ways, water supplies and sanitary wastes. 4. As to compliance with the Zoning Code, Finding 25 of the staff report is adopted by reference as if set forth in full. As depicted in the plat map, Ex. 2, each proposed lot will access a public road. As determined in Finding of Fact No. 5, the steep slopes and landslide hazards on the project site can be safely developed. As determined in Finding of Fact No. 6, the proposal provides for adequate public facilities. RMC 4-7-080(I)(1): …The Hearing Examiner shall assure conformance with the general purposes of the Comprehensive Plan and adopted standards… 5. The proposed preliminary plat is consistent with the Renton Comprehensive Plan as outlined in Finding 24 of the staff report, which is incorporated by this reference as if set forth in full. RMC 4-7-120(A): No plan for the replatting, subdivision, or dedication of any areas shall be approved by the Hearing Examiner unless the streets shown therein are connected by surfaced road or street (according to City specifications) to an existing street or highway. 6. All of the internal roads of the proposed subdivision will be surfaced as required by City standards and ultimately connect to N 40th St, an existing road. RMC 4-7-120(B): The location of all streets shall conform to any adopted plans for streets in the City. 7. The City’s adopted street plans are not addressed in the staff report or anywhere else in the administrative record. However, the proposal has been reviewed by the City’s Public Works department and it is presumed that Public Works staff would have required conformance to any applicable street plans. RMC 4-7-120(C): If a subdivision is located in the area of an officially designed [sic] trail, provisions shall be made for reservation of the right-of-way or for easements to the City for trail purposes. 8. The subdivision is not located in the area of an officially designated trail. RMC 4-7-130(C): A plat, short plat, subdivision or dedication shall be prepared in conformance with the following provisions: 1. Land Unsuitable for Subdivision: Land which is found to be unsuitable for subdivision includes land with features likely to be harmful to the safety and general health of the future residents (such as lands adversely affected by flooding, steep slopes, or rock formations). Land which the Department 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 PRELIMINARY PLAT and SHORELINE PERMIT- 9 or the Hearing Examiner considers inappropriate for subdivision shall not be subdivided unless adequate safeguards are provided against these adverse conditions. a. Flooding/Inundation: If any portion of the land within the boundary of a preliminary plat is subject to flooding or inundation, that portion of the subdivision must have the approval of the State according to chapter 86.16 RCW before the Department and the Hearing Examiner shall consider such subdivision. b. Steep Slopes: A plat, short plat, subdivision or dedication which would result in the creation of a lot or lots that primarily have slopes forty percent (40%) or greater as measured per RMC 4-3- 050J1a, without adequate area at lesser slopes upon which development may occur, shall not be approved. … 3. Land Clearing and Tree Retention: Shall comply with RMC 4-4-130, Tree Retention and Land Clearing Regulations. 4. Streams: a. Preservation: Every reasonable effort shall be made to preserve existing streams, bodies of water, and wetland areas. b. Method: If a stream passes through any of the subject property, a plan shall be presented which indicates how the stream will be preserved. The methodologies used should include an overflow area, and an attempt to minimize the disturbance of the natural channel and stream bed. c. Culverting: The piping or tunneling of water shall be discouraged and allowed only when going under streets. d. Clean Water: Every effort shall be made to keep all streams and bodies of water clear of debris and pollutants. 9. The criterion is met. The land is suitable for a subdivision as the stormwater design assures that it will not contribute to flooding and that water quality will not be adversely affected. The steep slopes and landslide hazard of the project site is suitable for development as noted in Finding of Fact No. 5 of this decision. No piping or tunneling of streams is proposed. Trees will be retained as required by RMC 4-4-130 as determined in Finding of Fact No. 5 of this decision. RMC 4-7-140: Approval of all subdivisions located in either single family residential or multi-family residential zones as defined in the Zoning Code shall be contingent upon the subdivider’s dedication of land or providing fees in lieu of dedication to the City, all as necessary to mitigate the adverse 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 PRELIMINARY PLAT and SHORELINE PERMIT- 10 effects of development upon the existing park and recreation service levels. The requirements and procedures for this mitigation shall be per the City of Renton Parks Mitigation Resolution. 10. City ordinances require the payment of park impact fees prior to building permit issuance. As discussed in Finding of Fact No. 6 of this decision, no other open space or park requirements apply to the proposal. RMC 4-7-150(A): The proposed street system shall extend and create connections between existing streets unless otherwise approved by the Public Works Department. Prior to approving a street system that does not extend or connect, the Reviewing Official shall find that such exception shall meet the requirements of subsection E3 of this Section. The roadway classifications shall be as defined and designated by the Department. 11. The proposed street system connects to existing streets and provides for future connections to all properties that have the potential for future connections. RMC 4-7-150(B): All proposed street names shall be approved by the City. 12. As conditioned. RMC 4-7-150(C): Streets intersecting with existing or proposed public highways, major or secondary arterials shall be held to a minimum. 13. There is no intersection with a public highway or major or secondary arterial1. RMC 4-7-150(D): The alignment of all streets shall be reviewed and approved by the Public Works Department. The street standards set by RMC 4-6-060 shall apply unless otherwise approved. Street alignment offsets of less than one hundred twenty five feet (125') are not desirable, but may be approved by the Department upon a showing of need but only after provision of all necessary safety measures. 14. As determined in Finding of Fact 6, the Public Works Department has reviewed and approved the adequacy of streets, which includes compliance with applicable street standards. RMC 4-7-150(E): 1. Grid: A grid street pattern shall be used to connect existing and new development and shall be the predominant street pattern in any subdivision permitted by this Section. 1 The staff report notes that N. 40th is a collector arterial. If this is the same as a “secondary” arterial then it must be concluded that the proposed intersection is unavoidable, as the only other alternatives would be connections to Park Avenue N. or Lake Washington Boulevard, also classified as collector arterials. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 PRELIMINARY PLAT and SHORELINE PERMIT- 11 2. Linkages: Linkages, including streets, sidewalks, pedestrian or bike paths, shall be provided within and between neighborhoods when they can create a continuous and interconnected network of roads and pathways. Implementation of this requirement shall comply with Comprehensive Plan Transportation Element Objective T-A and Policies T-9 through T-16 and Community Design Element, Objective CD-M and Policies CD-50 and CD-60. 3. Exceptions: a. The grid pattern may be adjusted to a “flexible grid” by reducing the number of linkages or the alignment between roads, where the following factors are present on site: i. Infeasible due to topographical/environmental constraints; and/or ii. Substantial improvements are existing. 4. Connections: Prior to adoption of a complete grid street plan, reasonable connections that link existing portions of the grid system shall be made. At a minimum, stub streets shall be required within subdivisions to allow future connectivity. 5. Alley Access: Alley access is the preferred street pattern for all new residential development except in the Residential Low Density land use designation (RC, R-1, and R-4 zones). All new residential development in an area that has existing alleys shall utilize alley access. New residential development in areas without existing alleys shall utilize alley access for interior lots. If the developer or property owner demonstrates that alley access is not practical, the use of alleys may not be required. The City will consider the following factors in determining whether the use of alleys is not practical: a. Size: The new development is a short plat. b. Topography: The topography of the site proposed for development is not conducive for an alley configuration. c. Environmental Impacts: The use of alleys would have more of a negative impact on the environment than a street pattern without alleys. d. If site characteristics allow for the effective use of alleys. “Alleys” shall mean singular or plural in this subsection. 6. Alternative Configurations: Offset or loop roads are the preferred alternative configurations. 7. Cul-de-Sac Streets: Cul-de-sac streets may only be permitted by the Reviewing Official where due to demonstrable physical constraints no future connection to a larger street pattern is physically possible. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 PRELIMINARY PLAT and SHORELINE PERMIT- 12 15. As shown in the aerial photograph in the staff report, the project does not necessitate any new grid connections, since the grid consists of a network of collector arterials and none of those arterials need to pass through the project site. A stub road within the proposal provides for future connectivity to the south as contemplated by the criterion above and the hammerhead on the western half of the project appears to be necessary as no alternative within the configuration of the parcel appears to be feasible. The staff report does not identify why alley access is not used for the proposal. Compliance with the criterion above regarding alley access will be made a condition of approval. As conditioned, the criterion above is met. RMC 4-7-150(F): All adjacent rights-of-way and new rights-of-way dedicated as part of the plat, including streets, roads, and alleys, shall be graded to their full width and the pavement and sidewalks shall be constructed as specified in the street standards or deferred by the Planning/Building/Public Works Administrator or his/her designee. 16. As proposed. RMC 4-7-150(G): Streets that may be extended in the event of future adjacent platting shall be required to be dedicated to the plat boundary line. Extensions of greater depth than an average lot shall be improved with temporary turnarounds. Dedication of a full-width boundary street shall be required in certain instances to facilitate future development. 17. Streets that may be extended in the event of future adjacent platting have been extended to the plat boundary line as required by the criterion quoted above. RMC 4-7-170(A): Insofar as practical, side lot lines shall be at right angles to street lines or radial to curved street lines. 18. As depicted in Ex. 2, some side yard lot lines are not at right lines to street lines. The conditions of approval will require that the applicant demonstrate the satisfaction of staff that right angles are not practical. RMC 4-7-170(B): Each lot must have access to a public street or road. Access may be by private access easement street per the requirements of the street standards. 19. As previously determined, each lot has access to a public street. RMC 4-7-170(C): The size, shape, and orientation of lots shall meet the minimum area and width requirements of the applicable zoning classification and shall be appropriate for the type of development and use contemplated. Further subdivision of lots within a plat approved through the provisions of this Chapter must be consistent with the then-current applicable maximum density requirement as measured within the plat as a whole. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 PRELIMINARY PLAT and SHORELINE PERMIT- 13 20. As previously determined, the proposed lots comply with the zoning standards of the R-6 zone, which includes area, width and density. RMC 4-7-170(D): Width between side lot lines at their foremost points (i.e., the points where the side lot lines intersect with the street right-of-way line) shall not be less than eighty percent (80%) of the required lot width except in the cases of (1) pipestem lots, which shall have a minimum width of twenty feet (20') and (2) lots on a street curve or the turning circle of cul-de-sac (radial lots), which shall be a minimum of thirty five feet (35'). 21. As shown in Ex. 2, the requirement is satisfied. RMC 4-7-170(E): All lot corners at intersections of dedicated public rights-of-way, except alleys, shall have minimum radius of fifteen feet (15'). 22. As conditioned. RMC 4-7-190(A): Due regard shall be shown to all natural features such as large trees, watercourses, and similar community assets. Such natural features should be preserved, thereby adding attractiveness and value to the property. 23. As determined in Finding of Fact No. 5, the proposal provides for the retention of significant trees as required by the City’s tree retention ordinance. There are no other natural features that can be legally required to be preserved at the site. RMC 4-7-200(A): Unless septic tanks are specifically approved by the Public Works Department and the King County Health Department, sanitary sewers shall be provided by the developer at no cost to the City and designed in accordance with City standards. Side sewer lines shall be installed eight feet (8') into each lot if sanitary sewer mains are available, or provided with the subdivision development. 24. As conditioned. RMC 4-7-200(B): An adequate drainage system shall be provided for the proper drainage of all surface water. Cross drains shall be provided to accommodate all natural water flow and shall be of sufficient length to permit full-width roadway and required slopes. The drainage system shall be designed per the requirements of RMC 4-6-030, Drainage (Surface Water) Standards. The drainage system shall include detention capacity for the new street areas. Residential plats shall also include detention capacity for future development of the lots. Water quality features shall also be designed to provide capacity for the new street paving for the plat. 25. The proposal provides for adequate drainage that is in conformance with applicable City drainage standards as determined in Finding of Fact No. 6. The City’s stormwater standards, which are 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 PRELIMINARY PLAT and SHORELINE PERMIT- 14 incorporated into the technical information report and will be further implemented during civil plan review, ensure compliance with all of the standards in the criterion quoted above. RMC 4-7-200(C): The water distribution system including the locations of fire hydrants shall be designed and installed in accordance with City standards as defined by the Department and Fire Department requirements. 26. The details of the water distribution system and location of fire hydrants will be subject to City engineering civil review as part of final plat review. RMC 4-7-200(D): All utilities designed to serve the subdivision shall be placed underground. Any utilities installed in the parking strip shall be placed in such a manner and depth to permit the planting of trees. Those utilities to be located beneath paved surfaces shall be installed, including all service connections, as approved by the Department. Such installation shall be completed and approved prior to the application of any surface material. Easements may be required for the maintenance and operation of utilities as specified by the Department. 27. As conditioned. RMC 4-7-200(E): Any cable TV conduits shall be undergrounded at the same time as other basic utilities are installed to serve each lot. Conduit for service connections shall be laid to each lot line by subdivider as to obviate the necessity for disturbing the street area, including sidewalks, or alley improvements when such service connections are extended to serve any building. The cost of trenching, conduit, pedestals and/or vaults and laterals as well as easements therefore required to bring service to the development shall be borne by the developer and/or land owner. The subdivider shall be responsible only for conduit to serve his development. Conduit ends shall be elbowed to final ground elevation and capped. The cable TV company shall provide maps and specifications to the subdivider and shall inspect the conduit and certify to the City that it is properly installed. 28. As conditioned. RMC 4-7-210: A. MONUMENTS: Concrete permanent control monuments shall be established at each and every controlling corner of the subdivision. Interior monuments shall be located as determined by the Department. All surveys shall be per the City of Renton surveying standards. B. SURVEY: All other lot corners shall be marked per the City surveying standards. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 PRELIMINARY PLAT and SHORELINE PERMIT- 15 C. STREET SIGNS: The subdivider shall install all street name signs necessary in the subdivision. 29. As conditioned. Shoreline Permit RMC 4-9-190(B)(7): In order to be approved, the Administrator of the Department of Community and Economic Development or designee must find that a proposal is consistent with the following criteria: a. All regulations of the Shoreline Master Program appropriate to the shoreline designation and the type of use or development proposed shall be met, except those bulk and dimensional standards that have been modified by approval of a shoreline variance. b. All policies of the Shoreline Master Program appropriate to the shoreline area designation and the type of use or development activity proposed shall be considered and substantial compliance demonstrated. A reasonable proposal that cannot fully conform to these policies may be permitted, provided it is demonstrated to the Administrator of the Department of Community and Economic Development or designee that the proposal is clearly consistent with the overall goals, objectives and intent of the Shoreline Master Program. c. For projects located on Lake Washington the criteria in RCW 90.58.020 regarding shorelines of statewide significance and relevant policies and regulations of the Shoreline Master Program shall also be adhered to. 30. The proposal meets the criterion quoted above for the reasons identified in Finding No. 28 of the staff report, adopted by this reference as if set forth in full. The staff report does not directly address the shoreline of statewide significance policies of RCW 90.58.020, but those policies are clearly met since (1) as determined in Finding of Fact No. 5 of this decision the proposal will result in no net loss of shoreline ecological function, (2) the proposal will not adversely affect navigation or shoreline public access and (3) the proposal will not create any adverse impacts to the shoreline environment. DECISION The preliminary plat and shoreline substantial development permit applications meet all applicable permit review criteria for the reasons identified in the conclusion of law of this decision and are approved, subject to the following conditions: 1. All proposed street names shall be approved by the City. 2. All lot corners at intersections of dedicated public rights-of-way, except alleys, shall have minimum radius of fifteen feet (15'). 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 PRELIMINARY PLAT and SHORELINE PERMIT- 16 3. Side sewer lines shall be installed eight feet (8') into each lot if sanitary sewer mains are available, or provided with the subdivision development. 4. All utilities designed to serve the subdivision shall be placed underground. Any utilities installed in the parking strip shall be placed in such a manner and depth to permit the planting of trees. Those utilities to be located beneath paved surfaces shall be installed, including all service connections, as approved by the Department of Public Works. Such installation shall be completed and approved prior to the application of any surface material. Easements may be required for the maintenance and operation of utilities as specified by the Department of Public Works. 5. Any cable TV conduits shall be undergrounded at the same time as other basic utilities are installed to serve each lot. Conduit for service connections shall be laid to each lot line by Applicant as to obviate the necessity for disturbing the street area, including sidewalks, or alley improvements when such service connections are extended to serve any building. The cost of trenching, conduit, pedestals and/or vaults and laterals as well as easements therefore required to bring service to the development shall be borne by the developer and/or land owner. The applicant shall be responsible only for conduit to serve his development. Conduit ends shall be elbowed to final ground elevation and capped. The cable TV company shall provide maps and specifications to the applicant and shall inspect the conduit and certify to the City that it is properly installed. 6. If it hasn’t done so already, the applicant shall demonstrate to the satisfaction of staff that it is not practical to have right angled lot lines with street lines as required by RMC 4-7-170(A). In the alternative the applicant may apply for any modifications or waivers to RMC 4-7-170(A) authorized by code. 7. If it hasn’t done so already, the applicant shall demonstrate to the satisfaction of staff that alley access for the proposed lots is not feasible as required by RMC 4-7-150(E)(5). In the alternative the applicant may apply for any modifications or waivers to RMC 4-7- 150(E)(5) authorized by code. 8. The applicant shall comply with the mitigation measures issued as part of the Determination of Non-Significance - Mitigated, dated May 6, 2016. 9. The applicant shall demonstrate compliance with the minimum lot dimensional standards of the Residential-6 zone prior to issuance of a construction permit. A note on the face of the Final Plat shall be recorded if lot dimension averaging is utilized. 10. The applicant shall record a note on the face of the Final Plat if setback averaging is utilized. 11. The applicant shall create a dual open space and tree protection tract at the southwest corner of the plat to retain the western red cedar in perpetuity. A note to this effect shall be recorded on the face of the Plat map. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 PRELIMINARY PLAT and SHORELINE PERMIT- 17 12. The applicant shall remove any invasive species and replant with native drought tolerant landscaping (trees, shrubs and groundcover) within the open space tract. 13. The applicant shall cover the vault tract with landscaping. A final detailed landscape plan shall be submitted to and approved by the City of Renton Project Manager prior to construction permit approval. 14. The applicant shall provide a permanent six foot (6’) tall fence along the south border of the open space tract and Lot 6 to prevent direct access to the Easthaven Short Plat private driveway. The fencing detail and location shall be identified on the final landscaping plan. 15. The applicant shall demonstrate compliance with the maximum retaining wall height standards. A final detailed grading plan shall be submitted to and approved by the City of Renton Project Manager prior to issuance of a construction permit. Alternatively, the applicant may submit a formal request for modification to staff for consideration to deviate from the retaining wall height standards of the code. 16. The applicant shall provide a pathway to connect the common open space tract to the development. The pathway shall be a minimum three feet (3') in width and made of paved asphalt, concrete, or porous material such as porous paving stones, crushed gravel with soil stabilizers, or paving blocks with planted joints. In addition, one easily accessible amenity, such as a park bench (no structures), shall be provided within the open space area. The details of the amenity shall be identified on the final landscaping plan for review and approval by the Current Planning Project Manager, prior to construction permit issuance. 17. The applicant install a temporary sign from grading and utility construction permit through building permit occupancy that discourages unnecessary or unwarranted trips onto the private drive, serving 3818, 3824, 3830, and 3836 Lake Washington Blvd N. The details of the sign and location must be submitted to and approved by the City of Renton Project Manager prior to issuance of a construction permit. 18. As discussed in Finding of Fact No. 5(A) of this decision, the applicant shall orient the front façades of Lots 3-6, to Lake Washington Blvd N or Road B. The applicant shall choose which street of the two streets is subject to this condition. As required by RMC 4- 2-115(E)(3), the front door of the homes shall be located on the façade closest to the street adjacent to the front façade. A note to this effect shall be recorded on the face of the Plat map. 19. The applicant shall create a Home Owners Association (“HOA”) that retains or improves the existing vegetation within the open space tract. A draft HOA document has been submitted as part of the application. A final HOA shall be submitted to, and approved by, the City of Renton Project Manager and the City Attorney prior to Final Plat recording. Such documents shall be recorded concurrently with the Final Plat. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 PRELIMINARY PLAT and SHORELINE PERMIT- 18 DATED this 4th day of July, 2016. City of Renton Hearing Examiner Appeal Right and Valuation Notices RMC 4-8-080 provides that the final decision of the hearing examiner is subject to appeal to the Renton City Council. RMC 4-8-110(E)(14) requires appeals of the hearing examiner’s decision to be filed within fourteen (14) calendar days from the date of the hearing examiner’s decision. A request for reconsideration to the hearing examiner may also be filed within this 14 day appeal period as identified in RMC 4-8-110(E)(13) and RMC 4-8-100(G)(9). A new fourteen (14) day appeal period shall commence upon the issuance of the reconsideration. Additional information regarding the appeal process may be obtained from the City Clerk’s Office, Renton City Hall – 7th floor, (425) 430-6510. Affected property owners may request a change in valuation for property tax purposes notwithstanding any program of revaluation. Senza Lakeview Final Technical Information Report CPH Project No. 0139-15-001 May 1, 2018 CP|H CONSULTANTS Page 20 SECTION 7 – OTHER PERMITS Construction and Grading Permits will be obtained from the City of Renton for roadway, storm drainage, and sanitary sewer improvements proposed for the infrastructure serving the subdivision. An NPDES General Construction Stormwater Permit from the Washington State Department of Ecology to discharge stormwater during construction and is provided in Appendix G. Preliminary Plat Approval will be obtained from the City of Renton to establish the layout of the land division and to ensure the proposed plat is in accordance with COR adopted standards. Individual building permits will be required for the on-site walls and the individual home structures. Senza Lakeview Final Technical Information Report CPH Project No. 0139-15-001 May 1, 2018 CP|H CONSULTANTS Page 21 SECTION 8 – CSWPPP ANALYSIS AND DESIGN Site specific details and provisions for the temporary erosion and sediment control (ESC) facilities are provided with the improvement plans that accompany this TIR. The proposed facilities have been selected and sized in accordance with the recommendations provided in the KCSWDM standards. In addition to the site-specific ESC measures, the following general Best Management Practices (BMPs) for sediment control shall also be implemented in accordance with the provisions of the KCSWDM: 1. Clearing Limits Construction clearing limits fence or silt fence will be installed by the contractor along the entire project corridor to prevent disturbance of project areas not designated for construction. These fences will be installed prior to clearing and grading activities where appropriate. 2. Cover Measures Temporary and permanent cover measures will be provided by the contractor to protect disturbed areas. Disturbed areas will be seeded and mulched to provide permanent cover measure and to reduce erosion within seven days, if those areas not scheduled for immediate work. 3. Perimeter Protection The contractor will install silt fences as indicated on the drawings prior to any up slope clearing, grading and trenching activities in order to reduce the transport of sediment offsite. 4. Traffic Area Stabilization Stabilized pads of quarry spalls will be installed by the contractor at all egress points from the project site as required to reduce the amount of sediment transported onto paved roads or other offsite areas by motor vehicles. It is not anticipated that a construction entrance will be required given the existing roadway. 5. Sediment Retention Sediment retention will be provided by silt fencing and catch basin inlet protection at the locations and dimensions shown on the project drawings. 6. Surface Water Control Surface water control will include ditches, temporary culverts, check dams, and/or other inlet and outlet protection at the locations and dimensions shown on the drawings. 7. Dust Control Water and/or street sweeping equipment will be used by the contractor to control dust emissions during construction operations. 8. Wet Season Requirements If soils are exposed during the period of October 1 to March 31, the contractor will mulch and seed or otherwise cover as much disturbed area as possible by the first week of October, in order to provide protective ground cover for the wet season. The contractor will also conform to the following wet season special provisions: A. Apply cover measures to disturbed areas that are to remain unworked for more than two days. Senza Lakeview Final Technical Information Report CPH Project No. 0139-15-001 May 1, 2018 CP|H CONSULTANTS Page 22 B. Protect stockpiles that are to remain unworked for more than 12 hours. No area is to be left uncovered/denuded longer than 12 hours during the winter months. C. Provide onsite stockpiles of cover materials sufficient to cover all disturbed areas. D. Seed all areas that are to be unworked during the wet season by the end of the first week of October. E. Apply mulch to all seeded areas for protection. F. Provide onsite storage of 50 linear feet of silt fence (and the necessary stakes) for every acre of disturbed area. Straw bales are to be stockpiled onsite for use in an emergency. G. Provide construction road and parking lot stabilization areas for all sites. H. Provide additional sediment retention as required by the City of Renton Engineer. I. Provide additional surface water controls as required by the City of Renton Engineer. J. Implement construction phasing and more conservative BMPs for construction activity near surface waters (to be evaluated). K. Review and maintain TESC measures on a weekly basis and within 24-hours after any runoff-producing event. 9. Sensitive Areas Restrictions No sensitive areas are located on-site. 10. Maintenance Requirements All ESC measures will be maintained and reviewed on a regular basis following the standard maintenance requirements identified in the project drawings. An ESC supervisor will be designated by the contractor and the name, address and phone number of the ESC supervisor will be given to the City prior to the start of construction. A sign will be posted at the primary entrance to the project site identifying the ESC supervisor and his/her phone number. The ESC supervisor will inspect the site at least once a month during the dry season, weekly during the wet season, and within 24 hours of each runoff-producing storm. A standard ESC maintenance report will be used as a written record of all maintenance. The contractor will be responsible for phasing of erosion and sediment controls during construction so that they are coordinated with construction activities. The contractor will also be responsible for maintenance of temporary controls during construction, including removal of accumulated sediment, and for the removal of the controls and remaining accumulated sediment at the completion of construction. 11. Final Stabilization Prior to obtaining final construction approval, the site shall be stabilized, the structural ESC measures removed and drainage facilities cleaned. To obtain final construction approval, the following conditions must be met: • All disturbed areas of the site should be vegetated or otherwise permanently stabilized in accordance with project BMPs. At a minimum, disturbed areas should be seeded and mulched to provide a high likelihood that sufficient cover will develop shortly after final approval. The plans include erosion control notes and specifications for hydro-seeding and mulching disturbed areas. • Structural measures such as silt fences, pipe slope drains, storm drain inlet protection and sediment traps and ponds shall be removed once the proposed improvements are complete and vegetated areas are stabilized. All permanent surface water facilities shall be cleaned completely and restored to working order prior to removal of ESC facilities. Senza Lakeview Final Technical Information Report CPH Project No. 0139-15-001 May 1, 2018 CP|H CONSULTANTS Page 23 SECTION 9 – BOND QUANTITIES, FACILITY SUMMARIES, AND DECLARATION OF COVENANT All required bonds, facility summaries, and covenants are provided with the final submittal. Senza Lakeview Final Technical Information Report CPH Project No. 0139-15-001 May 1, 2018 CP|H CONSULTANTS Page 24 SECTION 10 – OPERATIONS AND MAINTENANCE MANUAL The on-site storm drainage conveyance facilities for this project will be publicly maintained by the City of Renton. The water quality facilities will be privately maintained and designed in accordance with KCSWDM. A site specific operations and maintenance manual for the private facilities will be completed prior to final recording. Site Planning Civil Engineering Project Management Land Development Consulting FIGURES LAKE WASHINGTON BLVDN 40TH STPARK AVE N SENZA LAKEVIEWROADWAY GRADING, DRAINAGE AND SANITARY SEWER IMPROVEMENTSCALL BEFOREYOU DIG1-800-424-5555Copyright © 2018 CPH Consultants, LLC. All Rights Reserved.CPHONSULTANTS11431 WILLOWS RD. NE, SUITE 120 REDMOND, WA 98052Phone: (425) 285-2390 | FAX: (425) 285-2389www.cphconsultants.comSite Planning • Civil EngineeringLand Use Consulting • Project ManagementIN COMPLIANCE WITH CITY OF RENTON STANDARDSPTN.OF SW 1/4 OF NW 1/4 OF SEC. 32, TWP 24N, R5E W.M.SENZA LAKEVIEW TED-40-3934 LAU16-000165 U-16006676PR16-000315SENZA LAKEVIEWEXISTING CONDITIONSIN FEETPLAN0N3060 86LAKE WASHINGTON BLVD NORTH 40TH STREETPARK AVENUE NORTH CB120CB115CB125CB130CB61CB65CB60CB55CB70CB75CB71CB10CB15CB20CB140CB135789121415161113CB761710652134CB145EXIST. CB 2EXIST. CB 1CB200CB205CB210EXIST. CB 4CB5EXIST CB 00CB305CB310LEGEND10RDSENZA LAKEVIEWROADWAY GRADING, DRAINAGE AND SANITARY SEWER IMPROVEMENTSCALL BEFOREYOU DIG1-800-424-5555Copyright © 2018 CPH Consultants, LLC. All Rights Reserved.CPHONSULTANTS11431 WILLOWS RD. NE, SUITE 120 REDMOND, WA 98052Phone: (425) 285-2390 | FAX: (425) 285-2389www.cphconsultants.comSite Planning • Civil EngineeringLand Use Consulting • Project ManagementIN COMPLIANCE WITH CITY OF RENTON STANDARDSPTN.OF SW 1/4 OF NW 1/4 OF SEC. 32, TWP 24N, R5E W.M.SENZA LAKEVIEW TED-40-3934 LAU16-000165 U-16006676PR16-000315SENZA LAKEVIEWDEVELOPED SITE CONDITIONSINDIVIDUAL LOT BMP'SIN FEETPLAN0N3060 SITE BASINBYPASS BASINADDITIONAL INTAKEBASINSTORMFILTER BASINPARK AVE N N 40TH STLAKE WASHINGTON BLVDIN FEETPLAN0N3060PRE-DEVELOPED SITE CONDITIONSDEVELOPED SITE CONDITIONSEXISTING SITE CONDITIONSSENZA LAKEVIEWROADWAY GRADING, DRAINAGE AND SANITARY SEWER IMPROVEMENTSCALL BEFOREYOU DIG1-800-424-5555Copyright © 2018 CPH Consultants, LLC. All Rights Reserved.CPHONSULTANTS11431 WILLOWS RD. NE, SUITE 120 REDMOND, WA 98052Phone: (425) 285-2390 | FAX: (425) 285-2389www.cphconsultants.comSite Planning • Civil EngineeringLand Use Consulting • Project ManagementP:\project\0139\15001\Reports\CAD\Figure 5- DRAINAGE BASINS.dwg5/1/2018 10:22 AM BRYCE BESSETTE IN COMPLIANCE WITH CITY OF RENTON STANDARDSPTN.OF SW 1/4 OF NW 1/4 OF SEC. 32, TWP 24N, R5E W.M.SENZA LAKEVIEW TED-40-3934 LAU16-000165 U-16006676PR16-000315SENZA LAKEVIEWDRAINAGE BASINS LAKE WASHINGTON BOULEVARDPARK AVENUE NN 40TH STREETN 38TH STREETN 36TH STREETN 37TH STREETWELLS AVENUE NN 36TH STREETN 38TH STREETPROJECT BASINTOTAL AREA: 4.42 ACIMPERVIOUS AREA: 2.43 ACTILL GRASS: 1.99 ACBASIN A2:TOTAL AREA: 10.15 ACIMPERVIOUS AREA: 6.13 ACTILL GRASS: 4.02 ACBASIN A3:TOTAL AREA: 10.78 ACIMPERVIOUS AREA: 6.53 ACTILL GRASS: 4.25 ACBASIN A1:TOTAL AREA: 4.72 ACIMPERVIOUS AREA: 2.67 ACTILL GRASS: 2.05 ACBASIN A4:TOTAL AREA: 3.07 ACIMPERVIOUS AREA: 1.83 ACTILL GRASS: 1.24 ACBNSF BASIN:TOTAL AREA: 0.78 ACIMPERVIOUS AREA: 0.41 ACTILL GRASS: 0.37 ACBASIN A5:TOTAL AREA: 1.68 ACIMPERVIOUS AREA: 1.06 ACTILL GRASS: 0.62 ACTRIBUTARY BASINTOTAL AREA: 0.05 ACIMPERVIOUS AREA: 0.03 ACTILL GRASS: 0.02 ACIN FEETPLAN0N100200SENZA LAKEVIEWROADWAY GRADING, DRAINAGE AND SANITARY SEWER IMPROVEMENTSCALL BEFOREYOU DIG1-800-424-5555Copyright © 2018 CPH Consultants, LLC. All Rights Reserved.CPHONSULTANTS11431 WILLOWS RD. NE, SUITE 120 REDMOND, WA 98052Phone: (425) 285-2390 | FAX: (425) 285-2389www.cphconsultants.comSite Planning • Civil EngineeringLand Use Consulting • Project ManagementP:\project\0139\15001\Reports\CAD\Figure 6 - UPSTREAM BASINS.dwg5/1/2018 10:23 AM BRYCE BESSETTE IN COMPLIANCE WITH CITY OF RENTON STANDARDSPTN.OF SW 1/4 OF NW 1/4 OF SEC. 32, TWP 24N, R5E W.M.SENZA LAKEVIEW TED-40-3934 LAU16-000165 U-16006676PR16-000315SENZA LAKEVIEWDRAINAGE BASINS PARK AVE NN 40TH ST LAKE WASHINGTON BLVDEXIST. CB 1, EXIST. CB 2, CB20, CB145, CB15, CB10, CB5, CB135, EXIST. CB 6, EXIST. CB 5, CB130, CB120, CB125, CB115, CB140, CB76, CB75, CB70, CB71, CB65, CB61, CB60, CB55,CB210, CB205, CB200, EXIST. CB 4, EXIST. CB 8, EXIST. CB 7, EXIST. CB 9, EXIST. CB 10, EXIST CB 00, CB305, CB310, IN FEETPLAN 0 N 40 80 SENZA LAKEVIEW ROADWAY GRADING, DRAINAGE AND SANITARY SEWER IMPROVEMENTS CALL BEFORE YOU DIG 1-800-424-5555 Copyright © 2018 CPH Consultants, LLC. All Rights Reserved. CP H ONSULTANTS 11431 WILLOWS RD. NE, SUITE 120 REDMOND, WA 98052 Phone: (425) 285-2390 | FAX: (425) 285-2389www.cphconsultants.com Site Planning • Civil EngineeringLand Use Consulting • Project Management P:\project\0139\15001\Reports\CAD\Figure 7 - SUB-BASINS.dwg5/1/2018 10:28 AM BRYCE BESSETTEIN COMPLIANCE WITH CITY OF RENTON STANDARDS PTN.OF SW 1/4 OF NW 1/4 OF SEC. 32, TWP 24N, R5E W.M.SENZA LAKEVIEWTED-40-3934LAU16-000165U-16006676PR16-000315SENZA LAKEVIEWDRAINAGE SUB-BASINS 1,128188 City of Renton Print map Template This map is a user generated static output from an Internet mapping site and is for reference only. Data layers that appear on this map may or may not be accurate, current, or otherwise reliable. THIS MAP IS NOT TO BE USED FOR NAVIGATIONWGS_1984_Web_Mercator_Auxiliary_Sphere Notes None 03/03/2016 Legend 128 0 64 128 Feet Information Technology - GIS RentonMapSupport@Rentonwa.gov City and County Boundary Other City of Renton Addresses Parcels Network Structures Inlet Manhole Utility Vault Unknown Structure Control Structure Pump Station Discharge Point Water Quality Detention Facilities Pond Tank Vault Wetland Pipe Culvert Open Drains Virtual Drainline Facility Outline Private Network Structures Inlet Manhole Utility Vault Unknown Structure Private Control Structure Private Discharge Point Private Water Quality Private Detention Facilities Pond Tank Vault Wetland Private Pipe Private Culvert Private Open Drains Private Facility Outline Flow Control BMP Fence Stormwater Ponds Facility Transfer 641107 Offsite Conveyance Map This map is a user generated static output from an Internet mapping site and is for reference only. Data layers that appear on this map may or may not be accurate, current, or otherwise reliable. THIS MAP IS NOT TO BE USED FOR NAVIGATIONWGS_1984_Web_Mercator_Auxiliary_Sphere Notes Offsite Conveyance Map 06/27/2017 Legend 73 0 36 73 Feet Information Technology - GIS RentonMapSupport@Rentonwa.gov City and County Boundary Other City of Renton Addresses Parcels Network Structures Inlet Manhole Utility Vault Unknown Structure Control Structure Pump Station Discharge Point Water Quality Detention Facilities Pond Tank Vault Wetland Stormwater Main Culvert Open Drains Virtual Drainline Facility Outline Private Network Structures Inlet Manhole Utility Vault Unknown Structure Private Control Structure Private Discharge Point Private Water Quality Private Detention Facilities Pond Tank Vault Wetland Private Pipe Private Culvert Private Open Drains Private Facility Outline Flow Control BMP Fence 39LF 18" CONC. S=27.16% CB132959 RIM=36.12 (SOLID) IE(18" SE)=29.48 IE(24" NW)=29.48 52LF 24" S=3.97% 19LF 24" (NEW) S=4.74% 27LF 24" RGRCP S=8.21% CB114828 RIM=29.50 (SOLID) IE(24" SE)=24.40 IE(24" SW)=24.3585LF 24" RGRCP S=6.02% CB114573 RIM=25.85 (SOLID) IE(24" NE)=19.23 IE(30"NW)=19.15 81LF 30" RGRCP S=0.19% CB114822 RIM=24.54 (SOLID) IE(30" SE)=19.00 IE(30" SW)=18.84 40LF 30" RGRCP S=0.00% CB114823 RIM=24.63 (SOLID) IE(30" NE)=18.78 IE(30" SW)=18.78 40LF 30" RGRCP S=0.00% CB114824 RIM=24.61 (SOLID) IE(30" NE)=18.81 IE(30"SW)=18.81 66LF 30" RGRCP S=-0.09% CB114575 RIM=23.77 (SOLID) IE(30" NE)=18.87 IE(30" SW)=18.87 6LF 30" RGRCP S=5.33% OUTLET IE(30")=18.55 CB310 TRIBUTARY AREA=2,300 SQ. FT. CB310 (NEW) RIM=30.42 (SOLID) IE(24" NW)=26.60 IE(24" E)=26.60 (NEW) IE(12" SE)=27.60 (NEW) CB305 (NEW) RIM=30.42 (SOLID) IE(24" NW)=27.50 (NEW) IE(24" SW)=27.50 20.57LF 8.21% Site Planning Civil Engineering Project Management Land Development Consulting APPENDIX A NRCS SOILS REPORT Soil Map—King County Area, Washington Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 1/22/2016 Page 1 of 35263980526400052640205264040526406052640805264100526412052639805264000526402052640405264060526408052641005264120559870559890559910559930559950559970559990560010560030560050560070560090560110 559870 559890 559910 559930 559950 559970 559990 560010 560030 560050 560070 560090 560110 47° 31' 40'' N 122° 12' 17'' W47° 31' 40'' N122° 12' 5'' W47° 31' 34'' N 122° 12' 17'' W47° 31' 34'' N 122° 12' 5'' WN Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 10N WGS84 0 50 100 200 300Feet 0 15 30 60 90Meters Map Scale: 1:1,150 if printed on A landscape (11" x 8.5") sheet. MAP LEGEND MAP INFORMATION Area of Interest (AOI) Area of Interest (AOI) Soils Soil Map Unit Polygons Soil Map Unit Lines Soil Map Unit Points Special Point Features Blowout Borrow Pit Clay Spot Closed Depression Gravel Pit Gravelly Spot Landfill Lava Flow Marsh or swamp Mine or Quarry Miscellaneous Water Perennial Water Rock Outcrop Saline Spot Sandy Spot Severely Eroded Spot Sinkhole Slide or Slip Sodic Spot Spoil Area Stony Spot Very Stony Spot Wet Spot Other Special Line Features Water Features Streams and Canals Transportation Rails Interstate Highways US Routes Major Roads Local Roads Background Aerial Photography The soil surveys that comprise your AOI were mapped at 1:24,000. Warning: Soil Map may not be valid at this scale. Enlargement of maps beyond the scale of mapping can cause misunderstanding of the detail of mapping and accuracy of soil line placement. The maps do not show the small areas of contrasting soils that could have been shown at a more detailed scale. Please rely on the bar scale on each map sheet for map measurements. Source of Map: Natural Resources Conservation Service Web Soil Survey URL: http://websoilsurvey.nrcs.usda.gov Coordinate System: Web Mercator (EPSG:3857) Maps from the Web Soil Survey are based on the Web Mercator projection, which preserves direction and shape but distorts distance and area. A projection that preserves area, such as the Albers equal-area conic projection, should be used if more accurate calculations of distance or area are required. This product is generated from the USDA-NRCS certified data as of the version date(s) listed below. Soil Survey Area: King County Area, Washington Survey Area Data: Version 11, Sep 14, 2015 Soil map units are labeled (as space allows) for map scales 1:50,000 or larger. Date(s) aerial images were photographed: Aug 31, 2013—Oct 6, 2013 The orthophoto or other base map on which the soil lines were compiled and digitized probably differs from the background imagery displayed on these maps. As a result, some minor shifting of map unit boundaries may be evident. Soil Map—King County Area, Washington Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 1/22/2016 Page 2 of 3 Map Unit Legend King County Area, Washington (WA633) Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI AgC Alderwood gravelly sandy loam, 8 to 15 percent slopes 1.4 33.4% InC Indianola loamy sand, 5 to 15 percent slopes 2.7 66.6% Totals for Area of Interest 4.1 100.0% Soil Map—King County Area, Washington Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 1/22/2016 Page 3 of 3 Site Planning Civil Engineering Project Management Land Development Consulting APPENDIX B WWHM REPORT WWHM2012 PROJECT REPORT Backwater Conveyance Flows - 180320 3/23/2018 8:43:54 AM Page 2 General Model Information Project Name:Backwater Conveyance Flows - 180320 Site Name: Site Address: City: Report Date:3/23/2018 Gage:Seatac Data Start:1948/10/01 Data End:2009/09/30 Timestep:15 Minute Precip Scale:0.000 (adjusted) Version Date:2017/04/14 Version:4.2.13 POC Thresholds Low Flow Threshold for POC1:50 Percent of the 2 Year High Flow Threshold for POC1:100 Year Backwater Conveyance Flows - 180320 3/23/2018 8:43:54 AM Page 3 Landuse Basin Data Predeveloped Land Use Project Basin Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Mod 4.42 Pervious Total 4.42 Impervious Land Use acre Impervious Total 0 Basin Total 4.42 Element Flows To: Surface Interflow Groundwater Backwater Conveyance Flows - 180320 3/23/2018 8:43:54 AM Page 4 Basin A1 Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Mod 4.72 Pervious Total 4.72 Impervious Land Use acre Impervious Total 0 Basin Total 4.72 Element Flows To: Surface Interflow Groundwater Backwater Conveyance Flows - 180320 3/23/2018 8:43:54 AM Page 5 Basin A2 Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Mod 10.15 Pervious Total 10.15 Impervious Land Use acre Impervious Total 0 Basin Total 10.15 Element Flows To: Surface Interflow Groundwater Backwater Conveyance Flows - 180320 3/23/2018 8:43:54 AM Page 6 Basin A3 Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Mod 10.78 Pervious Total 10.78 Impervious Land Use acre Impervious Total 0 Basin Total 10.78 Element Flows To: Surface Interflow Groundwater Backwater Conveyance Flows - 180320 3/23/2018 8:43:54 AM Page 7 Basin A4 Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Mod 3.07 Pervious Total 3.07 Impervious Land Use acre Impervious Total 0 Basin Total 3.07 Element Flows To: Surface Interflow Groundwater Backwater Conveyance Flows - 180320 3/23/2018 8:43:54 AM Page 8 Basin A5 Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Mod 1.68 Pervious Total 1.68 Impervious Land Use acre Impervious Total 0 Basin Total 1.68 Element Flows To: Surface Interflow Groundwater Backwater Conveyance Flows - 180320 3/23/2018 8:43:54 AM Page 9 BNSF Basin Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Mod 0.78 Pervious Total 0.78 Impervious Land Use acre Impervious Total 0 Basin Total 0.78 Element Flows To: Surface Interflow Groundwater Backwater Conveyance Flows - 180320 3/23/2018 8:43:54 AM Page 10 TRIBUTARY BASIN Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Mod 0.05 Pervious Total 0.05 Impervious Land Use acre Impervious Total 0 Basin Total 0.05 Element Flows To: Surface Interflow Groundwater Backwater Conveyance Flows - 180320 3/23/2018 8:43:54 AM Page 11 Mitigated Land Use Project Basin Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Mod 1.99 Pervious Total 1.99 Impervious Land Use acre ROADS MOD 2.43 Impervious Total 2.43 Basin Total 4.42 Element Flows To: Surface Interflow Groundwater Backwater Conveyance Flows - 180320 3/23/2018 8:43:54 AM Page 12 Basin A1 Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Mod 2.05 Pervious Total 2.05 Impervious Land Use acre ROADS MOD 2.67 Impervious Total 2.67 Basin Total 4.72 Element Flows To: Surface Interflow Groundwater Backwater Conveyance Flows - 180320 3/23/2018 8:43:54 AM Page 13 Basin A2 Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Mod 4.02 Pervious Total 4.02 Impervious Land Use acre ROADS MOD 6.13 Impervious Total 6.13 Basin Total 10.15 Element Flows To: Surface Interflow Groundwater Backwater Conveyance Flows - 180320 3/23/2018 8:43:54 AM Page 14 Basin A3 Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Mod 4.25 Pervious Total 4.25 Impervious Land Use acre ROADS MOD 6.53 Impervious Total 6.53 Basin Total 10.78 Element Flows To: Surface Interflow Groundwater Backwater Conveyance Flows - 180320 3/23/2018 8:43:54 AM Page 15 Basin A4 Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Mod 1.24 Pervious Total 1.24 Impervious Land Use acre ROADS MOD 1.83 Impervious Total 1.83 Basin Total 3.07 Element Flows To: Surface Interflow Groundwater Backwater Conveyance Flows - 180320 3/23/2018 8:43:54 AM Page 16 Basin A5 Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Mod 0.62 Pervious Total 0.62 Impervious Land Use acre ROADS MOD 1.06 Impervious Total 1.06 Basin Total 1.68 Element Flows To: Surface Interflow Groundwater Backwater Conveyance Flows - 180320 3/23/2018 8:43:54 AM Page 17 BNSF Basin Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Mod 0.37 Pervious Total 0.37 Impervious Land Use acre ROADS MOD 0.41 Impervious Total 0.41 Basin Total 0.78 Element Flows To: Surface Interflow Groundwater Backwater Conveyance Flows - 180320 3/23/2018 8:43:54 AM Page 18 TRIBUTARY BASIN Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Mod 0.02 Pervious Total 0.02 Impervious Land Use acre ROADS MOD 0.03 Impervious Total 0.03 Basin Total 0.05 Element Flows To: Surface Interflow Groundwater Backwater Conveyance Flows - 180320 3/23/2018 8:43:54 AM Page 19 Routing Elements Predeveloped Routing Backwater Conveyance Flows - 180320 3/23/2018 8:43:54 AM Page 20 Mitigated Routing Backwater Conveyance Flows - 180320 3/23/2018 8:43:54 AM Page 21 Analysis Results POC 1 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #1 Total Pervious Area:35.65 Total Impervious Area:0 Mitigated Landuse Totals for POC #1 Total Pervious Area:14.56 Total Impervious Area:21.09 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #1 Return Period Flow(cfs) 2 year 1.061485 5 year 1.739338 10 year 2.175184 25 year 2.693641 50 year 3.052758 100 year 3.388191 Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow(cfs) 2 year 10.449361 5 year 13.654682 10 year 15.93644 25 year 19.00772 50 year 21.436563 100 year 23.989699 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #1 Year Predeveloped Mitigated 1949 1.222 14.540 1950 1.450 12.809 1951 2.319 8.526 1952 0.727 6.575 1953 0.588 7.531 1954 0.903 8.482 1955 1.443 9.853 1956 1.162 8.486 1957 0.938 10.458 1958 1.042 8.270 Backwater Conveyance Flows - 180320 3/23/2018 8:44:31 AM Page 22 1959 0.893 8.451 1960 1.600 9.632 1961 0.880 8.827 1962 0.548 7.100 1963 0.752 9.313 1964 1.066 8.289 1965 0.709 10.742 1966 0.681 7.343 1967 1.630 13.391 1968 0.917 16.062 1969 0.893 9.826 1970 0.717 9.664 1971 0.809 11.801 1972 1.761 12.395 1973 0.780 6.793 1974 0.865 11.366 1975 1.204 10.585 1976 0.860 8.974 1977 0.126 8.719 1978 0.728 11.655 1979 0.440 14.188 1980 2.073 17.893 1981 0.651 9.981 1982 1.344 15.041 1983 1.150 11.294 1984 0.693 7.547 1985 0.411 9.674 1986 1.819 8.785 1987 1.606 12.644 1988 0.634 8.091 1989 0.420 12.661 1990 3.844 20.856 1991 2.039 17.072 1992 0.832 7.934 1993 0.813 8.870 1994 0.273 7.635 1995 1.164 8.962 1996 2.692 12.645 1997 2.077 9.882 1998 0.508 9.818 1999 2.278 22.434 2000 0.809 9.981 2001 0.145 11.177 2002 0.938 13.002 2003 1.401 13.316 2004 1.497 21.354 2005 1.111 8.296 2006 1.249 8.025 2007 2.905 20.367 2008 3.541 15.877 2009 1.651 13.366 Ranked Annual Peaks Ranked Annual Peaks for Predeveloped and Mitigated. POC #1 Rank Predeveloped Mitigated 1 3.8438 22.4340 2 3.5414 21.3541 3 2.9053 20.8555 Backwater Conveyance Flows - 180320 3/23/2018 8:44:31 AM Page 23 4 2.6919 20.3666 5 2.3193 17.8930 6 2.2778 17.0718 7 2.0773 16.0623 8 2.0727 15.8772 9 2.0388 15.0411 10 1.8189 14.5401 11 1.7607 14.1880 12 1.6511 13.3907 13 1.6299 13.3659 14 1.6055 13.3160 15 1.6001 13.0020 16 1.4966 12.8086 17 1.4501 12.6612 18 1.4427 12.6452 19 1.4007 12.6435 20 1.3441 12.3950 21 1.2491 11.8006 22 1.2218 11.6547 23 1.2041 11.3663 24 1.1645 11.2936 25 1.1623 11.1771 26 1.1499 10.7421 27 1.1106 10.5853 28 1.0664 10.4580 29 1.0416 9.9813 30 0.9381 9.9809 31 0.9379 9.8822 32 0.9175 9.8525 33 0.9031 9.8256 34 0.8934 9.8183 35 0.8929 9.6738 36 0.8800 9.6644 37 0.8649 9.6320 38 0.8604 9.3129 39 0.8324 8.9742 40 0.8125 8.9618 41 0.8091 8.8699 42 0.8091 8.8271 43 0.7803 8.7853 44 0.7517 8.7191 45 0.7278 8.5263 46 0.7270 8.4857 47 0.7167 8.4822 48 0.7086 8.4508 49 0.6926 8.2962 50 0.6811 8.2889 51 0.6507 8.2700 52 0.6339 8.0907 53 0.5881 8.0253 54 0.5476 7.9339 55 0.5084 7.6351 56 0.4400 7.5467 57 0.4196 7.5308 58 0.4111 7.3429 59 0.2728 7.0996 60 0.1453 6.7929 61 0.1261 6.5746 Backwater Conveyance Flows - 180320 3/23/2018 8:44:31 AM Page 24 Backwater Conveyance Flows - 180320 3/23/2018 8:44:31 AM Page 25 Duration Flows Flow(cfs)Predev Mit Percentage Pass/Fail 0.5307 17139 108548 633 Fail 0.5596 15310 103821 678 Fail 0.5885 13738 99330 723 Fail 0.6173 12296 95202 774 Fail 0.6462 10972 91223 831 Fail 0.6751 9858 87480 887 Fail 0.7039 8941 84144 941 Fail 0.7328 8106 80935 998 Fail 0.7616 7317 77855 1064 Fail 0.7905 6633 74839 1128 Fail 0.8194 6025 71931 1193 Fail 0.8482 5544 69257 1249 Fail 0.8771 5065 66669 1316 Fail 0.9060 4673 64209 1374 Fail 0.9348 4291 61856 1441 Fail 0.9637 3959 59568 1504 Fail 0.9926 3619 57386 1585 Fail 1.0214 3324 55333 1664 Fail 1.0503 3048 53301 1748 Fail 1.0791 2804 51397 1832 Fail 1.1080 2550 49579 1944 Fail 1.1369 2357 47890 2031 Fail 1.1657 2152 46221 2147 Fail 1.1946 1968 44617 2267 Fail 1.2235 1801 43056 2390 Fail 1.2523 1669 41601 2492 Fail 1.2812 1522 40147 2637 Fail 1.3100 1372 38821 2829 Fail 1.3389 1259 37559 2983 Fail 1.3678 1162 36275 3121 Fail 1.3966 1086 35056 3227 Fail 1.4255 1014 33858 3339 Fail 1.4544 925 32725 3537 Fail 1.4832 863 31655 3668 Fail 1.5121 795 30586 3847 Fail 1.5410 740 29666 4008 Fail 1.5698 684 28747 4202 Fail 1.5987 632 27848 4406 Fail 1.6275 589 26993 4582 Fail 1.6564 545 26116 4791 Fail 1.6853 488 25303 5185 Fail 1.7141 449 24512 5459 Fail 1.7430 403 23763 5896 Fail 1.7719 361 23036 6381 Fail 1.8007 331 22394 6765 Fail 1.8296 298 21667 7270 Fail 1.8584 269 20987 7801 Fail 1.8873 236 20304 8603 Fail 1.9162 211 19673 9323 Fail 1.9450 185 19087 10317 Fail 1.9739 157 18531 11803 Fail 2.0028 133 17990 13526 Fail 2.0316 119 17425 14642 Fail 2.0605 104 16914 16263 Fail Backwater Conveyance Flows - 180320 3/23/2018 8:44:31 AM Page 26 2.0894 93 16414 17649 Fail 2.1182 81 15943 19682 Fail 2.1471 71 15485 21809 Fail 2.1759 66 15053 22807 Fail 2.2048 56 14613 26094 Fail 2.2337 47 14198 30208 Fail 2.2625 39 13811 35412 Fail 2.2914 29 13430 46310 Fail 2.3203 24 13043 54345 Fail 2.3491 21 12664 60304 Fail 2.3780 19 12329 64889 Fail 2.4068 15 11969 79793 Fail 2.4357 13 11629 89453 Fail 2.4646 10 11319 113190 Fail 2.4934 7 11013 157328 Fail 2.5223 7 10712 153028 Fail 2.5512 7 10446 149228 Fail 2.5800 6 10149 169150 Fail 2.6089 6 9882 164700 Fail 2.6377 6 9610 160166 Fail 2.6666 6 9330 155500 Fail 2.6955 5 9095 181900 Fail 2.7243 5 8864 177280 Fail 2.7532 5 8654 173080 Fail 2.7821 5 8438 168760 Fail 2.8109 5 8226 164520 Fail 2.8398 5 7984 159680 Fail 2.8687 5 7786 155720 Fail 2.8975 4 7555 188875 Fail 2.9264 3 7379 245966 Fail 2.9552 3 7199 239966 Fail 2.9841 3 7028 234266 Fail 3.0130 3 6874 229133 Fail 3.0418 3 6725 224166 Fail 3.0707 3 6551 218366 Fail 3.0996 3 6376 212533 Fail 3.1284 3 6216 207200 Fail 3.1573 3 6042 201400 Fail 3.1861 3 5884 196133 Fail 3.2150 3 5730 191000 Fail 3.2439 3 5623 187433 Fail 3.2727 3 5463 182100 Fail 3.3016 3 5345 178166 Fail 3.3305 3 5221 174033 Fail 3.3593 3 5088 169600 Fail 3.3882 3 4966 165533 Fail The development has an increase in flow durations from 1/2 Predeveloped 2 year flow to the 2 year flow or more than a 10% increase from the 2 year to the 50 year flow. The development has an increase in flow durations for more than 50% of the flows for the range of the duration analysis. Backwater Conveyance Flows - 180320 3/23/2018 8:44:31 AM Page 27 Water Quality Water Quality BMP Flow and Volume for POC #1 On-line facility volume:0 acre-feet On-line facility target flow:0 cfs. Adjusted for 15 min:0 cfs. Off-line facility target flow:0 cfs. Adjusted for 15 min:0 cfs. Backwater Conveyance Flows - 180320 3/23/2018 8:44:31 AM Page 28 LID Report Backwater Conveyance Flows - 180320 3/23/2018 8:44:58 AM Page 29 Model Default Modifications Total of 0 changes have been made. PERLND Changes No PERLND changes have been made. IMPLND Changes No IMPLND changes have been made. Backwater Conveyance Flows - 180320 3/23/2018 8:44:58 AM Page 30 Appendix Predeveloped Schematic Backwater Conveyance Flows - 180320 3/23/2018 8:44:58 AM Page 31 Mitigated Schematic Backwater Conveyance Flows - 180320 3/23/2018 8:44:58 AM Page 32 Predeveloped UCI File RUN GLOBAL WWHM4 model simulation START 1948 10 01 END 2009 09 30 RUN INTERP OUTPUT LEVEL 3 0 RESUME 0 RUN 1 UNIT SYSTEM 1 END GLOBAL FILES <File> <Un#> <-----------File Name------------------------------>*** <-ID-> *** WDM 26 Backwater Conveyance Flows - 180320.wdm MESSU 25 PreBackwater Conveyance Flows - 180320.MES 27 PreBackwater Conveyance Flows - 180320.L61 28 PreBackwater Conveyance Flows - 180320.L62 30 POCBackwater Conveyance Flows - 1803201.dat END FILES OPN SEQUENCE INGRP INDELT 00:15 PERLND 11 COPY 501 DISPLY 1 END INGRP END OPN SEQUENCE DISPLY DISPLY-INFO1 # - #<----------Title----------->***TRAN PIVL DIG1 FIL1 PYR DIG2 FIL2 YRND 1 Project Basin MAX 1 2 30 9 END DISPLY-INFO1 END DISPLY COPY TIMESERIES # - # NPT NMN *** 1 1 1 501 1 1 END TIMESERIES END COPY GENER OPCODE # # OPCD *** END OPCODE PARM # # K *** END PARM END GENER PERLND GEN-INFO <PLS ><-------Name------->NBLKS Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 11 C, Forest, Mod 1 1 1 1 27 0 END GEN-INFO *** Section PWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC *** 11 0 0 1 0 0 0 0 0 0 0 0 0 END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ***************************** PIVL PYR # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC ********* 11 0 0 4 0 0 0 0 0 0 0 0 0 1 9 END PRINT-INFO Backwater Conveyance Flows - 180320 3/23/2018 8:44:58 AM Page 33 PWAT-PARM1 <PLS > PWATER variable monthly parameter value flags *** # - # CSNO RTOP UZFG VCS VUZ VNN VIFW VIRC VLE INFC HWT *** 11 0 0 0 0 0 0 0 0 0 0 0 END PWAT-PARM1 PWAT-PARM2 <PLS > PWATER input info: Part 2 *** # - # ***FOREST LZSN INFILT LSUR SLSUR KVARY AGWRC 11 0 4.5 0.08 400 0.1 0.5 0.996 END PWAT-PARM2 PWAT-PARM3 <PLS > PWATER input info: Part 3 *** # - # ***PETMAX PETMIN INFEXP INFILD DEEPFR BASETP AGWETP 11 0 0 2 2 0 0 0 END PWAT-PARM3 PWAT-PARM4 <PLS > PWATER input info: Part 4 *** # - # CEPSC UZSN NSUR INTFW IRC LZETP *** 11 0.2 0.5 0.35 6 0.5 0.7 END PWAT-PARM4 PWAT-STATE1 <PLS > *** Initial conditions at start of simulation ran from 1990 to end of 1992 (pat 1-11-95) RUN 21 *** # - # *** CEPS SURS UZS IFWS LZS AGWS GWVS 11 0 0 0 0 2.5 1 0 END PWAT-STATE1 END PERLND IMPLND GEN-INFO <PLS ><-------Name-------> Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** END GEN-INFO *** Section IWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW IWAT SLD IWG IQAL *** END ACTIVITY PRINT-INFO <ILS > ******** Print-flags ******** PIVL PYR # - # ATMP SNOW IWAT SLD IWG IQAL ********* END PRINT-INFO IWAT-PARM1 <PLS > IWATER variable monthly parameter value flags *** # - # CSNO RTOP VRS VNN RTLI *** END IWAT-PARM1 IWAT-PARM2 <PLS > IWATER input info: Part 2 *** # - # *** LSUR SLSUR NSUR RETSC END IWAT-PARM2 IWAT-PARM3 <PLS > IWATER input info: Part 3 *** # - # ***PETMAX PETMIN END IWAT-PARM3 IWAT-STATE1 <PLS > *** Initial conditions at start of simulation # - # *** RETS SURS END IWAT-STATE1 Backwater Conveyance Flows - 180320 3/23/2018 8:44:58 AM Page 34 END IMPLND SCHEMATIC <-Source-> <--Area--> <-Target-> MBLK *** <Name> # <-factor-> <Name> # Tbl# *** Project Basin*** PERLND 11 4.42 COPY 501 12 PERLND 11 4.42 COPY 501 13 Basin A1*** PERLND 11 4.72 COPY 501 12 PERLND 11 4.72 COPY 501 13 Basin A2*** PERLND 11 10.15 COPY 501 12 PERLND 11 10.15 COPY 501 13 Basin A3*** PERLND 11 10.78 COPY 501 12 PERLND 11 10.78 COPY 501 13 Basin A4*** PERLND 11 3.07 COPY 501 12 PERLND 11 3.07 COPY 501 13 Basin A5*** PERLND 11 1.68 COPY 501 12 PERLND 11 1.68 COPY 501 13 BNSF Basin*** PERLND 11 0.78 COPY 501 12 PERLND 11 0.78 COPY 501 13 TRIBUTARY BASIN*** PERLND 11 0.05 COPY 501 12 PERLND 11 0.05 COPY 501 13 ******Routing****** END SCHEMATIC NETWORK <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** COPY 501 OUTPUT MEAN 1 1 48.4 DISPLY 1 INPUT TIMSER 1 <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** END NETWORK RCHRES GEN-INFO RCHRES Name Nexits Unit Systems Printer *** # - #<------------------><---> User T-series Engl Metr LKFG *** in out *** END GEN-INFO *** Section RCHRES*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # HYFG ADFG CNFG HTFG SDFG GQFG OXFG NUFG PKFG PHFG *** END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ******************* PIVL PYR # - # HYDR ADCA CONS HEAT SED GQL OXRX NUTR PLNK PHCB PIVL PYR ********* END PRINT-INFO HYDR-PARM1 RCHRES Flags for each HYDR Section *** # - # VC A1 A2 A3 ODFVFG for each *** ODGTFG for each FUNCT for each FG FG FG FG possible exit *** possible exit possible exit * * * * * * * * * * * * * * *** END HYDR-PARM1 HYDR-PARM2 Backwater Conveyance Flows - 180320 3/23/2018 8:44:58 AM Page 35 # - # FTABNO LEN DELTH STCOR KS DB50 *** <------><--------><--------><--------><--------><--------><--------> *** END HYDR-PARM2 HYDR-INIT RCHRES Initial conditions for each HYDR section *** # - # *** VOL Initial value of COLIND Initial value of OUTDGT *** ac-ft for each possible exit for each possible exit <------><--------> <---><---><---><---><---> *** <---><---><---><---><---> END HYDR-INIT END RCHRES SPEC-ACTIONS END SPEC-ACTIONS FTABLES END FTABLES EXT SOURCES <-Volume-> <Member> SsysSgap<--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # tem strg<-factor->strg <Name> # # <Name> # # *** WDM 2 PREC ENGL 1 PERLND 1 999 EXTNL PREC WDM 2 PREC ENGL 1 IMPLND 1 999 EXTNL PREC WDM 1 EVAP ENGL 0.76 PERLND 1 999 EXTNL PETINP WDM 1 EVAP ENGL 0.76 IMPLND 1 999 EXTNL PETINP END EXT SOURCES EXT TARGETS <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Volume-> <Member> Tsys Tgap Amd *** <Name> # <Name> # #<-factor->strg <Name> # <Name> tem strg strg*** COPY 501 OUTPUT MEAN 1 1 48.4 WDM 501 FLOW ENGL REPL END EXT TARGETS MASS-LINK <Volume> <-Grp> <-Member-><--Mult--> <Target> <-Grp> <-Member->*** <Name> <Name> # #<-factor-> <Name> <Name> # #*** MASS-LINK 12 PERLND PWATER SURO 0.083333 COPY INPUT MEAN END MASS-LINK 12 MASS-LINK 13 PERLND PWATER IFWO 0.083333 COPY INPUT MEAN END MASS-LINK 13 END MASS-LINK END RUN Backwater Conveyance Flows - 180320 3/23/2018 8:44:58 AM Page 36 Mitigated UCI File RUN GLOBAL WWHM4 model simulation START 1948 10 01 END 2009 09 30 RUN INTERP OUTPUT LEVEL 3 0 RESUME 0 RUN 1 UNIT SYSTEM 1 END GLOBAL FILES <File> <Un#> <-----------File Name------------------------------>*** <-ID-> *** WDM 26 Backwater Conveyance Flows - 180320.wdm MESSU 25 MitBackwater Conveyance Flows - 180320.MES 27 MitBackwater Conveyance Flows - 180320.L61 28 MitBackwater Conveyance Flows - 180320.L62 30 POCBackwater Conveyance Flows - 1803201.dat END FILES OPN SEQUENCE INGRP INDELT 00:15 PERLND 17 IMPLND 2 COPY 501 DISPLY 1 END INGRP END OPN SEQUENCE DISPLY DISPLY-INFO1 # - #<----------Title----------->***TRAN PIVL DIG1 FIL1 PYR DIG2 FIL2 YRND 1 Project Basin MAX 1 2 30 9 END DISPLY-INFO1 END DISPLY COPY TIMESERIES # - # NPT NMN *** 1 1 1 501 1 1 END TIMESERIES END COPY GENER OPCODE # # OPCD *** END OPCODE PARM # # K *** END PARM END GENER PERLND GEN-INFO <PLS ><-------Name------->NBLKS Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 17 C, Lawn, Mod 1 1 1 1 27 0 END GEN-INFO *** Section PWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC *** 17 0 0 1 0 0 0 0 0 0 0 0 0 END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ***************************** PIVL PYR # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC ********* 17 0 0 4 0 0 0 0 0 0 0 0 0 1 9 END PRINT-INFO Backwater Conveyance Flows - 180320 3/23/2018 8:44:58 AM Page 37 PWAT-PARM1 <PLS > PWATER variable monthly parameter value flags *** # - # CSNO RTOP UZFG VCS VUZ VNN VIFW VIRC VLE INFC HWT *** 17 0 0 0 0 0 0 0 0 0 0 0 END PWAT-PARM1 PWAT-PARM2 <PLS > PWATER input info: Part 2 *** # - # ***FOREST LZSN INFILT LSUR SLSUR KVARY AGWRC 17 0 4.5 0.03 400 0.1 0.5 0.996 END PWAT-PARM2 PWAT-PARM3 <PLS > PWATER input info: Part 3 *** # - # ***PETMAX PETMIN INFEXP INFILD DEEPFR BASETP AGWETP 17 0 0 2 2 0 0 0 END PWAT-PARM3 PWAT-PARM4 <PLS > PWATER input info: Part 4 *** # - # CEPSC UZSN NSUR INTFW IRC LZETP *** 17 0.1 0.25 0.25 6 0.5 0.25 END PWAT-PARM4 PWAT-STATE1 <PLS > *** Initial conditions at start of simulation ran from 1990 to end of 1992 (pat 1-11-95) RUN 21 *** # - # *** CEPS SURS UZS IFWS LZS AGWS GWVS 17 0 0 0 0 2.5 1 0 END PWAT-STATE1 END PERLND IMPLND GEN-INFO <PLS ><-------Name-------> Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 2 ROADS/MOD 1 1 1 27 0 END GEN-INFO *** Section IWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW IWAT SLD IWG IQAL *** 2 0 0 1 0 0 0 END ACTIVITY PRINT-INFO <ILS > ******** Print-flags ******** PIVL PYR # - # ATMP SNOW IWAT SLD IWG IQAL ********* 2 0 0 4 0 0 0 1 9 END PRINT-INFO IWAT-PARM1 <PLS > IWATER variable monthly parameter value flags *** # - # CSNO RTOP VRS VNN RTLI *** 2 0 0 0 0 0 END IWAT-PARM1 IWAT-PARM2 <PLS > IWATER input info: Part 2 *** # - # *** LSUR SLSUR NSUR RETSC 2 400 0.05 0.1 0.08 END IWAT-PARM2 IWAT-PARM3 <PLS > IWATER input info: Part 3 *** # - # ***PETMAX PETMIN 2 0 0 Backwater Conveyance Flows - 180320 3/23/2018 8:44:58 AM Page 38 END IWAT-PARM3 IWAT-STATE1 <PLS > *** Initial conditions at start of simulation # - # *** RETS SURS 2 0 0 END IWAT-STATE1 END IMPLND SCHEMATIC <-Source-> <--Area--> <-Target-> MBLK *** <Name> # <-factor-> <Name> # Tbl# *** Project Basin*** PERLND 17 1.99 COPY 501 12 PERLND 17 1.99 COPY 501 13 IMPLND 2 2.43 COPY 501 15 Basin A1*** PERLND 17 2.05 COPY 501 12 PERLND 17 2.05 COPY 501 13 IMPLND 2 2.67 COPY 501 15 Basin A2*** PERLND 17 4.02 COPY 501 12 PERLND 17 4.02 COPY 501 13 IMPLND 2 6.13 COPY 501 15 Basin A3*** PERLND 17 4.25 COPY 501 12 PERLND 17 4.25 COPY 501 13 IMPLND 2 6.53 COPY 501 15 Basin A4*** PERLND 17 1.24 COPY 501 12 PERLND 17 1.24 COPY 501 13 IMPLND 2 1.83 COPY 501 15 Basin A5*** PERLND 17 0.62 COPY 501 12 PERLND 17 0.62 COPY 501 13 IMPLND 2 1.06 COPY 501 15 BNSF Basin*** PERLND 17 0.37 COPY 501 12 PERLND 17 0.37 COPY 501 13 IMPLND 2 0.41 COPY 501 15 TRIBUTARY BASIN*** PERLND 17 0.02 COPY 501 12 PERLND 17 0.02 COPY 501 13 IMPLND 2 0.03 COPY 501 15 ******Routing****** END SCHEMATIC NETWORK <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** COPY 501 OUTPUT MEAN 1 1 48.4 DISPLY 1 INPUT TIMSER 1 <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** END NETWORK RCHRES GEN-INFO RCHRES Name Nexits Unit Systems Printer *** # - #<------------------><---> User T-series Engl Metr LKFG *** in out *** END GEN-INFO *** Section RCHRES*** ACTIVITY <PLS > ************* Active Sections ***************************** Backwater Conveyance Flows - 180320 3/23/2018 8:44:58 AM Page 39 # - # HYFG ADFG CNFG HTFG SDFG GQFG OXFG NUFG PKFG PHFG *** END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ******************* PIVL PYR # - # HYDR ADCA CONS HEAT SED GQL OXRX NUTR PLNK PHCB PIVL PYR ********* END PRINT-INFO HYDR-PARM1 RCHRES Flags for each HYDR Section *** # - # VC A1 A2 A3 ODFVFG for each *** ODGTFG for each FUNCT for each FG FG FG FG possible exit *** possible exit possible exit * * * * * * * * * * * * * * *** END HYDR-PARM1 HYDR-PARM2 # - # FTABNO LEN DELTH STCOR KS DB50 *** <------><--------><--------><--------><--------><--------><--------> *** END HYDR-PARM2 HYDR-INIT RCHRES Initial conditions for each HYDR section *** # - # *** VOL Initial value of COLIND Initial value of OUTDGT *** ac-ft for each possible exit for each possible exit <------><--------> <---><---><---><---><---> *** <---><---><---><---><---> END HYDR-INIT END RCHRES SPEC-ACTIONS END SPEC-ACTIONS FTABLES END FTABLES EXT SOURCES <-Volume-> <Member> SsysSgap<--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # tem strg<-factor->strg <Name> # # <Name> # # *** WDM 2 PREC ENGL 1 PERLND 1 999 EXTNL PREC WDM 2 PREC ENGL 1 IMPLND 1 999 EXTNL PREC WDM 1 EVAP ENGL 0.76 PERLND 1 999 EXTNL PETINP WDM 1 EVAP ENGL 0.76 IMPLND 1 999 EXTNL PETINP END EXT SOURCES EXT TARGETS <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Volume-> <Member> Tsys Tgap Amd *** <Name> # <Name> # #<-factor->strg <Name> # <Name> tem strg strg*** COPY 1 OUTPUT MEAN 1 1 48.4 WDM 701 FLOW ENGL REPL COPY 501 OUTPUT MEAN 1 1 48.4 WDM 801 FLOW ENGL REPL END EXT TARGETS MASS-LINK <Volume> <-Grp> <-Member-><--Mult--> <Target> <-Grp> <-Member->*** <Name> <Name> # #<-factor-> <Name> <Name> # #*** MASS-LINK 12 PERLND PWATER SURO 0.083333 COPY INPUT MEAN END MASS-LINK 12 MASS-LINK 13 PERLND PWATER IFWO 0.083333 COPY INPUT MEAN END MASS-LINK 13 MASS-LINK 15 IMPLND IWATER SURO 0.083333 COPY INPUT MEAN END MASS-LINK 15 END MASS-LINK END RUN Backwater Conveyance Flows - 180320 3/23/2018 8:44:58 AM Page 40 Predeveloped HSPF Message File Backwater Conveyance Flows - 180320 3/23/2018 8:44:58 AM Page 41 Mitigated HSPF Message File Backwater Conveyance Flows - 180320 3/23/2018 8:44:58 AM Page 42 Disclaimer Legal Notice This program and accompanying documentation are provided 'as-is' without warranty of any kind. The entire risk regarding the performance and results of this program is assumed by End User. Clear Creek Solutions Inc. and the governmental licensee or sublicensees disclaim all warranties, either expressed or implied, including but not limited to implied warranties of program and accompanying documentation. In no event shall Clear Creek Solutions Inc. be liable for any damages whatsoever (including without limitation to damages for loss of business profits, loss of business information, business interruption, and the like) arising out of the use of, or inability to use this program even if Clear Creek Solutions Inc. or their authorized representatives have been advised of the possibility of such damages. Software Copyright © by : Clear Creek Solutions, Inc. 2005-2018; All Rights Reserved. Clear Creek Solutions, Inc. 6200 Capitol Blvd. Ste F Olympia, WA. 98501 Toll Free 1(866)943-0304 Local (360)943-0304 www.clearcreeksolutions.com WWHM2012 PROJECT REPORT StormFilter CB WQ Flow - Park Ave 6/26/2017 3:13:41 PM Page 2 General Model Information Project Name:StormFilter CB WQ Flow - Park Ave Site Name: Site Address: City: Report Date:6/26/2017 Gage:Seatac Data Start:1948/10/01 Data End:2009/09/30 Timestep:15 Minute Precip Scale:1.00 Version Date:2016/02/25 Version:4.2.12 POC Thresholds Low Flow Threshold for POC1:50 Percent of the 2 Year High Flow Threshold for POC1:50 Year StormFilter CB WQ Flow - Park Ave 6/26/2017 3:13:41 PM Page 3 Landuse Basin Data Predeveloped Land Use Basin 1 Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Mod 0.062 Pervious Total 0.062 Impervious Land Use acre Impervious Total 0 Basin Total 0.062 Element Flows To: Surface Interflow Groundwater StormFilter CB WQ Flow - Park Ave 6/26/2017 3:13:41 PM Page 4 Mitigated Land Use Basin 1 Bypass:No GroundWater:No Pervious Land Use acre Pervious Total 0 Impervious Land Use acre ROADS FLAT 0.062 Impervious Total 0.062 Basin Total 0.062 Element Flows To: Surface Interflow Groundwater StormFilter CB WQ Flow - Park Ave 6/26/2017 3:13:41 PM Page 5 Routing Elements Predeveloped Routing StormFilter CB WQ Flow - Park Ave 6/26/2017 3:13:41 PM Page 6 Mitigated Routing StormFilter CB WQ Flow - Park Ave 6/26/2017 3:13:41 PM Page 7 Analysis Results POC 1 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #1 Total Pervious Area:0.062 Total Impervious Area:0 Mitigated Landuse Totals for POC #1 Total Pervious Area:0 Total Impervious Area:0.062 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #1 Return Period Flow(cfs) 2 year 0.001846 5 year 0.003025 10 year 0.003783 25 year 0.004685 50 year 0.005309 100 year 0.005893 Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow(cfs) 2 year 0.023638 5 year 0.029858 10 year 0.034084 25 year 0.039565 50 year 0.043761 100 year 0.048058 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #1 Year Predeveloped Mitigated 1949 0.002 0.031 1950 0.003 0.033 1951 0.004 0.019 1952 0.001 0.017 1953 0.001 0.018 1954 0.002 0.019 1955 0.003 0.022 1956 0.002 0.021 1957 0.002 0.024 1958 0.002 0.020 StormFilter CB WQ Flow - Park Ave 6/26/2017 3:14:17 PM Page 8 1959 0.002 0.020 1960 0.003 0.020 1961 0.002 0.021 1962 0.001 0.018 1963 0.001 0.020 1964 0.002 0.020 1965 0.001 0.025 1966 0.001 0.017 1967 0.003 0.029 1968 0.002 0.033 1969 0.002 0.023 1970 0.001 0.022 1971 0.001 0.026 1972 0.003 0.027 1973 0.001 0.016 1974 0.002 0.024 1975 0.002 0.028 1976 0.001 0.019 1977 0.000 0.020 1978 0.001 0.025 1979 0.001 0.034 1980 0.004 0.030 1981 0.001 0.025 1982 0.002 0.035 1983 0.002 0.028 1984 0.001 0.018 1985 0.001 0.025 1986 0.003 0.021 1987 0.003 0.033 1988 0.001 0.020 1989 0.001 0.025 1990 0.007 0.042 1991 0.004 0.034 1992 0.001 0.018 1993 0.001 0.015 1994 0.000 0.017 1995 0.002 0.022 1996 0.005 0.023 1997 0.004 0.023 1998 0.001 0.023 1999 0.004 0.047 2000 0.001 0.023 2001 0.000 0.026 2002 0.002 0.030 2003 0.002 0.023 2004 0.003 0.044 2005 0.002 0.020 2006 0.002 0.018 2007 0.005 0.041 2008 0.006 0.033 2009 0.003 0.031 Ranked Annual Peaks Ranked Annual Peaks for Predeveloped and Mitigated. POC #1 Rank Predeveloped Mitigated 1 0.0067 0.0469 2 0.0062 0.0439 3 0.0051 0.0421 StormFilter CB WQ Flow - Park Ave 6/26/2017 3:14:17 PM Page 9 4 0.0047 0.0410 5 0.0040 0.0348 6 0.0040 0.0337 7 0.0036 0.0337 8 0.0036 0.0331 9 0.0035 0.0331 10 0.0032 0.0330 11 0.0031 0.0328 12 0.0029 0.0306 13 0.0028 0.0306 14 0.0028 0.0302 15 0.0028 0.0299 16 0.0026 0.0289 17 0.0025 0.0284 18 0.0025 0.0276 19 0.0024 0.0271 20 0.0023 0.0263 21 0.0022 0.0257 22 0.0021 0.0251 23 0.0021 0.0250 24 0.0020 0.0247 25 0.0020 0.0246 26 0.0020 0.0246 27 0.0019 0.0243 28 0.0019 0.0240 29 0.0018 0.0234 30 0.0016 0.0233 31 0.0016 0.0233 32 0.0016 0.0229 33 0.0016 0.0228 34 0.0016 0.0226 35 0.0016 0.0220 36 0.0015 0.0219 37 0.0015 0.0218 38 0.0015 0.0214 39 0.0014 0.0214 40 0.0014 0.0208 41 0.0014 0.0201 42 0.0014 0.0201 43 0.0014 0.0201 44 0.0013 0.0200 45 0.0013 0.0200 46 0.0013 0.0197 47 0.0012 0.0196 48 0.0012 0.0196 49 0.0012 0.0192 50 0.0012 0.0191 51 0.0011 0.0186 52 0.0011 0.0184 53 0.0010 0.0181 54 0.0010 0.0179 55 0.0009 0.0177 56 0.0008 0.0177 57 0.0007 0.0170 58 0.0007 0.0168 59 0.0005 0.0167 60 0.0003 0.0164 61 0.0002 0.0153 StormFilter CB WQ Flow - Park Ave 6/26/2017 3:14:17 PM Page 10 StormFilter CB WQ Flow - Park Ave 6/26/2017 3:14:17 PM Page 11 Duration Flows Flow(cfs)Predev Mit Percentage Pass/Fail 0.0009 17075 130686 765 Fail 0.0010 15492 127092 820 Fail 0.0010 14082 123563 877 Fail 0.0011 12816 120162 937 Fail 0.0011 11569 116954 1010 Fail 0.0011 10528 113938 1082 Fail 0.0012 9584 111072 1158 Fail 0.0012 8750 108185 1236 Fail 0.0013 8042 105490 1311 Fail 0.0013 7358 103008 1399 Fail 0.0014 6733 100527 1493 Fail 0.0014 6192 98110 1584 Fail 0.0015 5734 95886 1672 Fail 0.0015 5313 93662 1762 Fail 0.0015 4924 91480 1857 Fail 0.0016 4571 89405 1955 Fail 0.0016 4244 87330 2057 Fail 0.0017 3951 85213 2156 Fail 0.0017 3645 83331 2286 Fail 0.0018 3390 81491 2403 Fail 0.0018 3133 79609 2540 Fail 0.0019 2915 77855 2670 Fail 0.0019 2706 76101 2812 Fail 0.0019 2490 74369 2986 Fail 0.0020 2314 72701 3141 Fail 0.0020 2136 71139 3330 Fail 0.0021 1974 69599 3525 Fail 0.0021 1824 68059 3731 Fail 0.0022 1703 66605 3911 Fail 0.0022 1578 65172 4130 Fail 0.0023 1442 63760 4421 Fail 0.0023 1325 62391 4708 Fail 0.0023 1233 60979 4945 Fail 0.0024 1147 59760 5210 Fail 0.0024 1086 58520 5388 Fail 0.0025 1020 57322 5619 Fail 0.0025 948 56124 5920 Fail 0.0026 886 54884 6194 Fail 0.0026 825 53729 6512 Fail 0.0027 761 52616 6914 Fail 0.0027 725 51526 7107 Fail 0.0027 675 50499 7481 Fail 0.0028 623 49472 7940 Fail 0.0028 589 48488 8232 Fail 0.0029 549 47547 8660 Fail 0.0029 506 46585 9206 Fail 0.0030 469 45622 9727 Fail 0.0030 427 44703 10469 Fail 0.0030 388 43783 11284 Fail 0.0031 356 42906 12052 Fail 0.0031 328 42029 12813 Fail 0.0032 298 41238 13838 Fail 0.0032 270 40425 14972 Fail 0.0033 241 39633 16445 Fail StormFilter CB WQ Flow - Park Ave 6/26/2017 3:14:17 PM Page 12 0.0033 218 38885 17837 Fail 0.0034 198 38051 19217 Fail 0.0034 174 37281 21425 Fail 0.0034 152 36532 24034 Fail 0.0035 130 35783 27525 Fail 0.0035 119 35099 29494 Fail 0.0036 104 34436 33111 Fail 0.0036 95 33794 35572 Fail 0.0037 83 33153 39943 Fail 0.0037 74 32468 43875 Fail 0.0038 69 31848 46156 Fail 0.0038 61 31228 51193 Fail 0.0038 53 30650 57830 Fail 0.0039 46 30073 65376 Fail 0.0039 39 29495 75628 Fail 0.0040 29 28918 99717 Fail 0.0040 25 28404 113616 Fail 0.0041 22 27870 126681 Fail 0.0041 20 27335 136675 Fail 0.0042 17 26822 157776 Fail 0.0042 14 26308 187914 Fail 0.0042 12 25816 215133 Fail 0.0043 8 25303 316287 Fail 0.0043 7 24854 355057 Fail 0.0044 7 24362 348028 Fail 0.0044 7 23955 342214 Fail 0.0045 6 23464 391066 Fail 0.0045 6 23014 383566 Fail 0.0046 6 22587 376450 Fail 0.0046 6 22159 369316 Fail 0.0046 6 21752 362533 Fail 0.0047 5 21372 427440 Fail 0.0047 5 20952 419040 Fail 0.0048 5 20576 411520 Fail 0.0048 5 20244 404880 Fail 0.0049 5 19872 397440 Fail 0.0049 5 19475 389500 Fail 0.0050 5 19134 382680 Fail 0.0050 4 18844 471100 Fail 0.0050 4 18506 462650 Fail 0.0051 3 18183 606100 Fail 0.0051 3 17860 595333 Fail 0.0052 3 17522 584066 Fail 0.0052 3 17231 574366 Fail 0.0053 3 16916 563866 Fail 0.0053 3 16638 554600 Fail The development has an increase in flow durations from 1/2 Predeveloped 2 year flow to the 2 year flow or more than a 10% increase from the 2 year to the 50 year flow. The development has an increase in flow durations for more than 50% of the flows for the range of the duration analysis. StormFilter CB WQ Flow - Park Ave 6/26/2017 3:14:17 PM Page 13 Water Quality Water Quality BMP Flow and Volume for POC #1 On-line facility volume:0.0076 acre-feet On-line facility target flow:0.01 cfs. Adjusted for 15 min:0.01 cfs. Off-line facility target flow:0.0056 cfs. Adjusted for 15 min:0.0056 cfs. StormFilter CB WQ Flow - Park Ave 6/26/2017 3:14:17 PM Page 14 LID Report StormFilter CB WQ Flow - Park Ave 6/26/2017 3:14:21 PM Page 15 Model Default Modifications Total of 0 changes have been made. PERLND Changes No PERLND changes have been made. IMPLND Changes No IMPLND changes have been made. StormFilter CB WQ Flow - Park Ave 6/26/2017 3:14:21 PM Page 16 Appendix Predeveloped Schematic StormFilter CB WQ Flow - Park Ave 6/26/2017 3:14:21 PM Page 17 Mitigated Schematic StormFilter CB WQ Flow - Park Ave 6/26/2017 3:14:21 PM Page 18 Predeveloped UCI File StormFilter CB WQ Flow - Park Ave 6/26/2017 3:14:21 PM Page 19 Mitigated UCI File StormFilter CB WQ Flow - Park Ave 6/26/2017 3:14:21 PM Page 20 Predeveloped HSPF Message File StormFilter CB WQ Flow - Park Ave 6/26/2017 3:14:21 PM Page 21 Mitigated HSPF Message File StormFilter CB WQ Flow - Park Ave 6/26/2017 3:14:21 PM Page 22 Disclaimer Legal Notice This program and accompanying documentation are provided 'as-is' without warranty of any kind. The entire risk regarding the performance and results of this program is assumed by End User. Clear Creek Solutions Inc. and the governmental licensee or sublicensees disclaim all warranties, either expressed or implied, including but not limited to implied warranties of program and accompanying documentation. In no event shall Clear Creek Solutions Inc. be liable for any damages whatsoever (including without limitation to damages for loss of business profits, loss of business information, business interruption, and the like) arising out of the use of, or inability to use this program even if Clear Creek Solutions Inc. or their authorized representatives have been advised of the possibility of such damages. Software Copyright © by : Clear Creek Solutions, Inc. 2005-2017; All Rights Reserved. Clear Creek Solutions, Inc. 6200 Capitol Blvd. Ste F Olympia, WA. 98501 Toll Free 1(866)943-0304 Local (360)943-0304 www.clearcreeksolutions.com WWHM2012 PROJECT REPORT Unmitigated Flows for Sed Pond 4/19/2017 5:06:37 PM Page 2 General Model Information Project Name:Unmitigated Flows for Sed Pond Site Name: Site Address: City: Report Date:4/19/2017 Gage:Seatac Data Start:1948/10/01 Data End:2009/09/30 Timestep:15 Minute Precip Scale:1.00 Version Date:2016/02/25 Version:4.2.12 POC Thresholds Low Flow Threshold for POC1:50 Percent of the 2 Year High Flow Threshold for POC1:50 Year Unmitigated Flows for Sed Pond 4/19/2017 5:06:37 PM Page 3 Landuse Basin Data Predeveloped Land Use Predeveloped Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Mod 4.29 Pervious Total 4.29 Impervious Land Use acre Impervious Total 0 Basin Total 4.29 Element Flows To: Surface Interflow Groundwater Unmitigated Flows for Sed Pond 4/19/2017 5:06:37 PM Page 4 Mitigated Land Use Basin 1 Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Mod 2.02 Pervious Total 2.02 Impervious Land Use acre ROADS MOD 2.27 Impervious Total 2.27 Basin Total 4.29 Element Flows To: Surface Interflow Groundwater Unmitigated Flows for Sed Pond 4/19/2017 5:06:37 PM Page 5 Routing Elements Predeveloped Routing Unmitigated Flows for Sed Pond 4/19/2017 5:06:37 PM Page 6 Mitigated Routing Unmitigated Flows for Sed Pond 4/19/2017 5:06:37 PM Page 7 Analysis Results POC 1 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #1 Total Pervious Area:4.29 Total Impervious Area:0 Mitigated Landuse Totals for POC #1 Total Pervious Area:2.02 Total Impervious Area:2.27 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #1 Return Period Flow(cfs) 2 year 0.127736 5 year 0.209306 10 year 0.261754 25 year 0.324144 50 year 0.367359 100 year 0.407724 Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow(cfs) 2 year 1.161991 5 year 1.53087 10 year 1.795125 25 year 2.152622 50 year 2.436608 100 year 2.736187 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #1 Year Predeveloped Mitigated 1949 0.147 1.649 1950 0.175 1.454 1951 0.279 0.964 1952 0.087 0.723 1953 0.071 0.817 1954 0.109 0.944 1955 0.174 1.088 1956 0.140 0.949 1957 0.113 1.178 1958 0.125 0.910 Unmitigated Flows for Sed Pond 4/19/2017 5:07:12 PM Page 8 1959 0.108 0.910 1960 0.193 1.086 1961 0.106 0.982 1962 0.066 0.776 1963 0.090 1.041 1964 0.128 0.910 1965 0.085 1.213 1966 0.082 0.812 1967 0.196 1.529 1968 0.110 1.781 1969 0.107 1.108 1970 0.086 1.076 1971 0.097 1.314 1972 0.212 1.397 1973 0.094 0.731 1974 0.104 1.276 1975 0.145 1.197 1976 0.104 1.003 1977 0.015 0.970 1978 0.088 1.260 1979 0.053 1.538 1980 0.249 2.037 1981 0.078 1.106 1982 0.162 1.688 1983 0.138 1.236 1984 0.083 0.834 1985 0.049 1.068 1986 0.219 0.989 1987 0.193 1.378 1988 0.076 0.871 1989 0.050 1.363 1990 0.463 2.432 1991 0.245 1.960 1992 0.100 0.886 1993 0.098 0.959 1994 0.033 0.822 1995 0.140 0.990 1996 0.324 1.434 1997 0.250 1.116 1998 0.061 1.096 1999 0.274 2.530 2000 0.097 1.116 2001 0.017 1.215 2002 0.113 1.461 2003 0.169 1.502 2004 0.180 2.397 2005 0.134 0.934 2006 0.150 0.908 2007 0.350 2.293 2008 0.426 1.826 2009 0.199 1.441 Ranked Annual Peaks Ranked Annual Peaks for Predeveloped and Mitigated. POC #1 Rank Predeveloped Mitigated 1 0.4626 2.5305 2 0.4262 2.4323 3 0.3496 2.3970 Unmitigated Flows for Sed Pond 4/19/2017 5:07:12 PM Page 9 4 0.3239 2.2933 5 0.2791 2.0372 6 0.2741 1.9599 7 0.2500 1.8258 8 0.2494 1.7810 9 0.2453 1.6876 10 0.2189 1.6488 11 0.2119 1.5380 12 0.1987 1.5291 13 0.1961 1.5017 14 0.1932 1.4608 15 0.1926 1.4545 16 0.1801 1.4408 17 0.1745 1.4338 18 0.1736 1.3973 19 0.1686 1.3783 20 0.1617 1.3629 21 0.1503 1.3145 22 0.1470 1.2761 23 0.1449 1.2597 24 0.1401 1.2356 25 0.1399 1.2145 26 0.1384 1.2130 27 0.1336 1.1966 28 0.1283 1.1780 29 0.1253 1.1163 30 0.1129 1.1161 31 0.1129 1.1079 32 0.1104 1.1063 33 0.1087 1.0963 34 0.1075 1.0881 35 0.1075 1.0864 36 0.1059 1.0756 37 0.1041 1.0679 38 0.1035 1.0412 39 0.1002 1.0032 40 0.0978 0.9904 41 0.0974 0.9888 42 0.0974 0.9822 43 0.0939 0.9699 44 0.0905 0.9639 45 0.0876 0.9590 46 0.0875 0.9490 47 0.0863 0.9435 48 0.0853 0.9342 49 0.0833 0.9103 50 0.0820 0.9102 51 0.0783 0.9099 52 0.0763 0.9080 53 0.0708 0.8860 54 0.0659 0.8711 55 0.0612 0.8335 56 0.0530 0.8219 57 0.0505 0.8171 58 0.0495 0.8119 59 0.0328 0.7757 60 0.0175 0.7314 61 0.0152 0.7225 Unmitigated Flows for Sed Pond 4/19/2017 5:07:12 PM Page 10 Unmitigated Flows for Sed Pond 4/19/2017 5:07:12 PM Page 11 Duration Flows Flow(cfs)Predev Mit Percentage Pass/Fail 0.0639 17592 105618 600 Fail 0.0669 15930 101276 635 Fail 0.0700 14523 97084 668 Fail 0.0731 12816 91929 717 Fail 0.0761 11612 88336 760 Fail 0.0792 10572 84935 803 Fail 0.0823 9640 81812 848 Fail 0.0853 8840 78818 891 Fail 0.0884 8130 75845 932 Fail 0.0915 7443 73043 981 Fail 0.0945 6838 70369 1029 Fail 0.0976 6286 67845 1079 Fail 0.1007 5813 65343 1124 Fail 0.1037 5403 63076 1167 Fail 0.1068 5011 60808 1213 Fail 0.1099 4665 58648 1257 Fail 0.1129 4338 56595 1304 Fail 0.1160 4032 54627 1354 Fail 0.1190 3645 52189 1431 Fail 0.1221 3394 50328 1482 Fail 0.1252 3146 48638 1546 Fail 0.1282 2935 46991 1601 Fail 0.1313 2723 45430 1668 Fail 0.1344 2511 43954 1750 Fail 0.1374 2346 42564 1814 Fail 0.1405 2165 41131 1899 Fail 0.1436 2004 39826 1987 Fail 0.1466 1851 38543 2082 Fail 0.1497 1732 37323 2154 Fail 0.1528 1611 36126 2242 Fail 0.1558 1483 34992 2359 Fail 0.1589 1356 33816 2493 Fail 0.1620 1259 32768 2602 Fail 0.1650 1147 31377 2735 Fail 0.1681 1086 30436 2802 Fail 0.1712 1022 29495 2886 Fail 0.1742 957 28618 2990 Fail 0.1773 890 27763 3119 Fail 0.1804 834 26950 3231 Fail 0.1834 773 26137 3381 Fail 0.1865 730 25389 3477 Fail 0.1896 681 24619 3615 Fail 0.1926 634 23891 3768 Fail 0.1957 598 23271 3891 Fail 0.1988 564 22608 4008 Fail 0.2018 516 21902 4244 Fail 0.2049 478 21224 4440 Fail 0.2079 437 20585 4710 Fail 0.2110 388 19768 5094 Fail 0.2141 356 19201 5393 Fail 0.2171 329 18666 5673 Fail 0.2202 298 18095 6072 Fail 0.2233 272 17590 6466 Fail 0.2263 245 17088 6974 Fail Unmitigated Flows for Sed Pond 4/19/2017 5:07:12 PM Page 12 0.2294 220 16596 7543 Fail 0.2325 202 16181 8010 Fail 0.2355 179 15725 8784 Fail 0.2386 155 15287 9862 Fail 0.2417 133 14893 11197 Fail 0.2447 122 14480 11868 Fail 0.2478 109 14050 12889 Fail 0.2509 97 13670 14092 Fail 0.2539 89 13291 14933 Fail 0.2570 78 12915 16557 Fail 0.2601 69 12485 18094 Fail 0.2631 61 12140 19901 Fail 0.2662 54 11830 21907 Fail 0.2693 46 11501 25002 Fail 0.2723 39 11223 28776 Fail 0.2754 31 10955 35338 Fail 0.2785 25 10686 42744 Fail 0.2815 22 10421 47368 Fail 0.2846 20 10125 50625 Fail 0.2877 18 9862 54788 Fail 0.2907 14 9612 68657 Fail 0.2938 13 9366 72046 Fail 0.2969 11 9165 83318 Fail 0.2999 7 8932 127600 Fail 0.3030 7 8735 124785 Fail 0.3060 7 8451 120728 Fail 0.3091 6 8209 136816 Fail 0.3122 6 7993 133216 Fail 0.3152 6 7805 130083 Fail 0.3183 6 7623 127050 Fail 0.3214 6 7437 123950 Fail 0.3244 5 7274 145480 Fail 0.3275 5 7122 142440 Fail 0.3306 5 6956 139120 Fail 0.3336 5 6808 136160 Fail 0.3367 5 6652 133040 Fail 0.3398 5 6485 129700 Fail 0.3428 5 6331 126619 Fail 0.3459 5 6175 123500 Fail 0.3490 4 6027 150675 Fail 0.3520 3 5826 194200 Fail 0.3551 3 5672 189066 Fail 0.3582 3 5538 184600 Fail 0.3612 3 5407 180233 Fail 0.3643 3 5281 176033 Fail 0.3674 3 5170 172333 Fail The development has an increase in flow durations from 1/2 Predeveloped 2 year flow to the 2 year flow or more than a 10% increase from the 2 year to the 50 year flow. The development has an increase in flow durations for more than 50% of the flows for the range of the duration analysis. Unmitigated Flows for Sed Pond 4/19/2017 5:07:12 PM Page 13 Water Quality Water Quality BMP Flow and Volume for POC #1 On-line facility volume:0 acre-feet On-line facility target flow:0 cfs. Adjusted for 15 min:0 cfs. Off-line facility target flow:0 cfs. Adjusted for 15 min:0 cfs. Unmitigated Flows for Sed Pond 4/19/2017 5:07:12 PM Page 14 LID Report Unmitigated Flows for Sed Pond 4/19/2017 5:07:21 PM Page 15 Model Default Modifications Total of 0 changes have been made. PERLND Changes No PERLND changes have been made. IMPLND Changes No IMPLND changes have been made. Unmitigated Flows for Sed Pond 4/19/2017 5:07:21 PM Page 16 Appendix Predeveloped Schematic Unmitigated Flows for Sed Pond 4/19/2017 5:07:22 PM Page 17 Mitigated Schematic Unmitigated Flows for Sed Pond 4/19/2017 5:07:22 PM Page 18 Predeveloped UCI File RUN GLOBAL WWHM4 model simulation START 1948 10 01 END 2009 09 30 RUN INTERP OUTPUT LEVEL 3 0 RESUME 0 RUN 1 UNIT SYSTEM 1 END GLOBAL FILES <File> <Un#> <-----------File Name------------------------------>*** <-ID-> *** WDM 26 Unmitigated Flows for Sed Pond.wdm MESSU 25 PreUnmitigated Flows for Sed Pond.MES 27 PreUnmitigated Flows for Sed Pond.L61 28 PreUnmitigated Flows for Sed Pond.L62 30 POCUnmitigated Flows for Sed Pond1.dat END FILES OPN SEQUENCE INGRP INDELT 00:15 PERLND 11 COPY 501 DISPLY 1 END INGRP END OPN SEQUENCE DISPLY DISPLY-INFO1 # - #<----------Title----------->***TRAN PIVL DIG1 FIL1 PYR DIG2 FIL2 YRND 1 Predeveloped MAX 1 2 30 9 END DISPLY-INFO1 END DISPLY COPY TIMESERIES # - # NPT NMN *** 1 1 1 501 1 1 END TIMESERIES END COPY GENER OPCODE # # OPCD *** END OPCODE PARM # # K *** END PARM END GENER PERLND GEN-INFO <PLS ><-------Name------->NBLKS Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 11 C, Forest, Mod 1 1 1 1 27 0 END GEN-INFO *** Section PWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC *** 11 0 0 1 0 0 0 0 0 0 0 0 0 END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ***************************** PIVL PYR # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC ********* 11 0 0 4 0 0 0 0 0 0 0 0 0 1 9 END PRINT-INFO Unmitigated Flows for Sed Pond 4/19/2017 5:07:22 PM Page 19 PWAT-PARM1 <PLS > PWATER variable monthly parameter value flags *** # - # CSNO RTOP UZFG VCS VUZ VNN VIFW VIRC VLE INFC HWT *** 11 0 0 0 0 0 0 0 0 0 0 0 END PWAT-PARM1 PWAT-PARM2 <PLS > PWATER input info: Part 2 *** # - # ***FOREST LZSN INFILT LSUR SLSUR KVARY AGWRC 11 0 4.5 0.08 400 0.1 0.5 0.996 END PWAT-PARM2 PWAT-PARM3 <PLS > PWATER input info: Part 3 *** # - # ***PETMAX PETMIN INFEXP INFILD DEEPFR BASETP AGWETP 11 0 0 2 2 0 0 0 END PWAT-PARM3 PWAT-PARM4 <PLS > PWATER input info: Part 4 *** # - # CEPSC UZSN NSUR INTFW IRC LZETP *** 11 0.2 0.5 0.35 6 0.5 0.7 END PWAT-PARM4 PWAT-STATE1 <PLS > *** Initial conditions at start of simulation ran from 1990 to end of 1992 (pat 1-11-95) RUN 21 *** # - # *** CEPS SURS UZS IFWS LZS AGWS GWVS 11 0 0 0 0 2.5 1 0 END PWAT-STATE1 END PERLND IMPLND GEN-INFO <PLS ><-------Name-------> Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** END GEN-INFO *** Section IWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW IWAT SLD IWG IQAL *** END ACTIVITY PRINT-INFO <ILS > ******** Print-flags ******** PIVL PYR # - # ATMP SNOW IWAT SLD IWG IQAL ********* END PRINT-INFO IWAT-PARM1 <PLS > IWATER variable monthly parameter value flags *** # - # CSNO RTOP VRS VNN RTLI *** END IWAT-PARM1 IWAT-PARM2 <PLS > IWATER input info: Part 2 *** # - # *** LSUR SLSUR NSUR RETSC END IWAT-PARM2 IWAT-PARM3 <PLS > IWATER input info: Part 3 *** # - # ***PETMAX PETMIN END IWAT-PARM3 IWAT-STATE1 <PLS > *** Initial conditions at start of simulation # - # *** RETS SURS END IWAT-STATE1 Unmitigated Flows for Sed Pond 4/19/2017 5:07:22 PM Page 20 END IMPLND SCHEMATIC <-Source-> <--Area--> <-Target-> MBLK *** <Name> # <-factor-> <Name> # Tbl# *** Predeveloped*** PERLND 11 4.29 COPY 501 12 PERLND 11 4.29 COPY 501 13 ******Routing****** END SCHEMATIC NETWORK <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** COPY 501 OUTPUT MEAN 1 1 48.4 DISPLY 1 INPUT TIMSER 1 <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** END NETWORK RCHRES GEN-INFO RCHRES Name Nexits Unit Systems Printer *** # - #<------------------><---> User T-series Engl Metr LKFG *** in out *** END GEN-INFO *** Section RCHRES*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # HYFG ADFG CNFG HTFG SDFG GQFG OXFG NUFG PKFG PHFG *** END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ******************* PIVL PYR # - # HYDR ADCA CONS HEAT SED GQL OXRX NUTR PLNK PHCB PIVL PYR ********* END PRINT-INFO HYDR-PARM1 RCHRES Flags for each HYDR Section *** # - # VC A1 A2 A3 ODFVFG for each *** ODGTFG for each FUNCT for each FG FG FG FG possible exit *** possible exit possible exit * * * * * * * * * * * * * * *** END HYDR-PARM1 HYDR-PARM2 # - # FTABNO LEN DELTH STCOR KS DB50 *** <------><--------><--------><--------><--------><--------><--------> *** END HYDR-PARM2 HYDR-INIT RCHRES Initial conditions for each HYDR section *** # - # *** VOL Initial value of COLIND Initial value of OUTDGT *** ac-ft for each possible exit for each possible exit <------><--------> <---><---><---><---><---> *** <---><---><---><---><---> END HYDR-INIT END RCHRES SPEC-ACTIONS END SPEC-ACTIONS FTABLES END FTABLES EXT SOURCES <-Volume-> <Member> SsysSgap<--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # tem strg<-factor->strg <Name> # # <Name> # # *** WDM 2 PREC ENGL 1 PERLND 1 999 EXTNL PREC WDM 2 PREC ENGL 1 IMPLND 1 999 EXTNL PREC Unmitigated Flows for Sed Pond 4/19/2017 5:07:22 PM Page 21 WDM 1 EVAP ENGL 0.76 PERLND 1 999 EXTNL PETINP WDM 1 EVAP ENGL 0.76 IMPLND 1 999 EXTNL PETINP END EXT SOURCES EXT TARGETS <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Volume-> <Member> Tsys Tgap Amd *** <Name> # <Name> # #<-factor->strg <Name> # <Name> tem strg strg*** COPY 501 OUTPUT MEAN 1 1 48.4 WDM 501 FLOW ENGL REPL END EXT TARGETS MASS-LINK <Volume> <-Grp> <-Member-><--Mult--> <Target> <-Grp> <-Member->*** <Name> <Name> # #<-factor-> <Name> <Name> # #*** MASS-LINK 12 PERLND PWATER SURO 0.083333 COPY INPUT MEAN END MASS-LINK 12 MASS-LINK 13 PERLND PWATER IFWO 0.083333 COPY INPUT MEAN END MASS-LINK 13 END MASS-LINK END RUN Unmitigated Flows for Sed Pond 4/19/2017 5:07:22 PM Page 22 Mitigated UCI File RUN GLOBAL WWHM4 model simulation START 1948 10 01 END 2009 09 30 RUN INTERP OUTPUT LEVEL 3 0 RESUME 0 RUN 1 UNIT SYSTEM 1 END GLOBAL FILES <File> <Un#> <-----------File Name------------------------------>*** <-ID-> *** WDM 26 Unmitigated Flows for Sed Pond.wdm MESSU 25 MitUnmitigated Flows for Sed Pond.MES 27 MitUnmitigated Flows for Sed Pond.L61 28 MitUnmitigated Flows for Sed Pond.L62 30 POCUnmitigated Flows for Sed Pond1.dat END FILES OPN SEQUENCE INGRP INDELT 00:15 PERLND 17 IMPLND 2 COPY 501 DISPLY 1 END INGRP END OPN SEQUENCE DISPLY DISPLY-INFO1 # - #<----------Title----------->***TRAN PIVL DIG1 FIL1 PYR DIG2 FIL2 YRND 1 Basin 1 MAX 1 2 30 9 END DISPLY-INFO1 END DISPLY COPY TIMESERIES # - # NPT NMN *** 1 1 1 501 1 1 END TIMESERIES END COPY GENER OPCODE # # OPCD *** END OPCODE PARM # # K *** END PARM END GENER PERLND GEN-INFO <PLS ><-------Name------->NBLKS Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 17 C, Lawn, Mod 1 1 1 1 27 0 END GEN-INFO *** Section PWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC *** 17 0 0 1 0 0 0 0 0 0 0 0 0 END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ***************************** PIVL PYR # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC ********* 17 0 0 4 0 0 0 0 0 0 0 0 0 1 9 END PRINT-INFO Unmitigated Flows for Sed Pond 4/19/2017 5:07:22 PM Page 23 PWAT-PARM1 <PLS > PWATER variable monthly parameter value flags *** # - # CSNO RTOP UZFG VCS VUZ VNN VIFW VIRC VLE INFC HWT *** 17 0 0 0 0 0 0 0 0 0 0 0 END PWAT-PARM1 PWAT-PARM2 <PLS > PWATER input info: Part 2 *** # - # ***FOREST LZSN INFILT LSUR SLSUR KVARY AGWRC 17 0 4.5 0.03 400 0.1 0.5 0.996 END PWAT-PARM2 PWAT-PARM3 <PLS > PWATER input info: Part 3 *** # - # ***PETMAX PETMIN INFEXP INFILD DEEPFR BASETP AGWETP 17 0 0 2 2 0 0 0 END PWAT-PARM3 PWAT-PARM4 <PLS > PWATER input info: Part 4 *** # - # CEPSC UZSN NSUR INTFW IRC LZETP *** 17 0.1 0.25 0.25 6 0.5 0.25 END PWAT-PARM4 PWAT-STATE1 <PLS > *** Initial conditions at start of simulation ran from 1990 to end of 1992 (pat 1-11-95) RUN 21 *** # - # *** CEPS SURS UZS IFWS LZS AGWS GWVS 17 0 0 0 0 2.5 1 0 END PWAT-STATE1 END PERLND IMPLND GEN-INFO <PLS ><-------Name-------> Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 2 ROADS/MOD 1 1 1 27 0 END GEN-INFO *** Section IWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW IWAT SLD IWG IQAL *** 2 0 0 1 0 0 0 END ACTIVITY PRINT-INFO <ILS > ******** Print-flags ******** PIVL PYR # - # ATMP SNOW IWAT SLD IWG IQAL ********* 2 0 0 4 0 0 0 1 9 END PRINT-INFO IWAT-PARM1 <PLS > IWATER variable monthly parameter value flags *** # - # CSNO RTOP VRS VNN RTLI *** 2 0 0 0 0 0 END IWAT-PARM1 IWAT-PARM2 <PLS > IWATER input info: Part 2 *** # - # *** LSUR SLSUR NSUR RETSC 2 400 0.05 0.1 0.08 END IWAT-PARM2 IWAT-PARM3 <PLS > IWATER input info: Part 3 *** # - # ***PETMAX PETMIN 2 0 0 Unmitigated Flows for Sed Pond 4/19/2017 5:07:22 PM Page 24 END IWAT-PARM3 IWAT-STATE1 <PLS > *** Initial conditions at start of simulation # - # *** RETS SURS 2 0 0 END IWAT-STATE1 END IMPLND SCHEMATIC <-Source-> <--Area--> <-Target-> MBLK *** <Name> # <-factor-> <Name> # Tbl# *** Basin 1*** PERLND 17 2.02 COPY 501 12 PERLND 17 2.02 COPY 501 13 IMPLND 2 2.27 COPY 501 15 ******Routing****** END SCHEMATIC NETWORK <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** COPY 501 OUTPUT MEAN 1 1 48.4 DISPLY 1 INPUT TIMSER 1 <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** END NETWORK RCHRES GEN-INFO RCHRES Name Nexits Unit Systems Printer *** # - #<------------------><---> User T-series Engl Metr LKFG *** in out *** END GEN-INFO *** Section RCHRES*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # HYFG ADFG CNFG HTFG SDFG GQFG OXFG NUFG PKFG PHFG *** END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ******************* PIVL PYR # - # HYDR ADCA CONS HEAT SED GQL OXRX NUTR PLNK PHCB PIVL PYR ********* END PRINT-INFO HYDR-PARM1 RCHRES Flags for each HYDR Section *** # - # VC A1 A2 A3 ODFVFG for each *** ODGTFG for each FUNCT for each FG FG FG FG possible exit *** possible exit possible exit * * * * * * * * * * * * * * *** END HYDR-PARM1 HYDR-PARM2 # - # FTABNO LEN DELTH STCOR KS DB50 *** <------><--------><--------><--------><--------><--------><--------> *** END HYDR-PARM2 HYDR-INIT RCHRES Initial conditions for each HYDR section *** # - # *** VOL Initial value of COLIND Initial value of OUTDGT *** ac-ft for each possible exit for each possible exit <------><--------> <---><---><---><---><---> *** <---><---><---><---><---> END HYDR-INIT END RCHRES SPEC-ACTIONS Unmitigated Flows for Sed Pond 4/19/2017 5:07:22 PM Page 25 END SPEC-ACTIONS FTABLES END FTABLES EXT SOURCES <-Volume-> <Member> SsysSgap<--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # tem strg<-factor->strg <Name> # # <Name> # # *** WDM 2 PREC ENGL 1 PERLND 1 999 EXTNL PREC WDM 2 PREC ENGL 1 IMPLND 1 999 EXTNL PREC WDM 1 EVAP ENGL 0.76 PERLND 1 999 EXTNL PETINP WDM 1 EVAP ENGL 0.76 IMPLND 1 999 EXTNL PETINP END EXT SOURCES EXT TARGETS <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Volume-> <Member> Tsys Tgap Amd *** <Name> # <Name> # #<-factor->strg <Name> # <Name> tem strg strg*** COPY 1 OUTPUT MEAN 1 1 48.4 WDM 701 FLOW ENGL REPL COPY 501 OUTPUT MEAN 1 1 48.4 WDM 801 FLOW ENGL REPL END EXT TARGETS MASS-LINK <Volume> <-Grp> <-Member-><--Mult--> <Target> <-Grp> <-Member->*** <Name> <Name> # #<-factor-> <Name> <Name> # #*** MASS-LINK 12 PERLND PWATER SURO 0.083333 COPY INPUT MEAN END MASS-LINK 12 MASS-LINK 13 PERLND PWATER IFWO 0.083333 COPY INPUT MEAN END MASS-LINK 13 MASS-LINK 15 IMPLND IWATER SURO 0.083333 COPY INPUT MEAN END MASS-LINK 15 END MASS-LINK END RUN Unmitigated Flows for Sed Pond 4/19/2017 5:07:22 PM Page 26 Predeveloped HSPF Message File Unmitigated Flows for Sed Pond 4/19/2017 5:07:22 PM Page 27 Mitigated HSPF Message File Unmitigated Flows for Sed Pond 4/19/2017 5:07:22 PM Page 28 Disclaimer Legal Notice This program and accompanying documentation are provided 'as-is' without warranty of any kind. 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Clear Creek Solutions, Inc. 6200 Capitol Blvd. Ste F Olympia, WA. 98501 Toll Free 1(866)943-0304 Local (360)943-0304 www.clearcreeksolutions.com WWHM2012 PROJECT REPORT Water Quality Vault 3/16/2017 7:49:25 AM Page 2 General Model Information Project Name:Water Quality Vault Site Name: Site Address: City: Report Date:3/16/2017 Gage:Seatac Data Start:1948/10/01 Data End:2009/09/30 Timestep:15 Minute Precip Scale:1.000 Version Date:2016/07/25 Version:4.2.12 POC Thresholds Low Flow Threshold for POC1:50 Percent of the 2 Year High Flow Threshold for POC1:50 Year Water Quality Vault 3/16/2017 7:49:25 AM Page 3 Landuse Basin Data Predeveloped Land Use Basin 1 Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Mod 4.07 Pervious Total 4.07 Impervious Land Use acre Impervious Total 0 Basin Total 4.07 Element Flows To: Surface Interflow Groundwater Water Quality Vault 3/16/2017 7:49:25 AM Page 4 Mitigated Land Use Basin 1 Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Mod 1.97 Pervious Total 1.97 Impervious Land Use acre ROADS MOD 2.1 Impervious Total 2.1 Basin Total 4.07 Element Flows To: Surface Interflow Groundwater Water Quality Vault 3/16/2017 7:49:25 AM Page 5 Routing Elements Predeveloped Routing Water Quality Vault 3/16/2017 7:49:25 AM Page 6 Mitigated Routing Water Quality Vault 3/16/2017 7:49:25 AM Page 7 Analysis Results POC 1 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #1 Total Pervious Area:4.07 Total Impervious Area:0 Mitigated Landuse Totals for POC #1 Total Pervious Area:1.97 Total Impervious Area:2.1 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #1 Return Period Flow(cfs) 2 year 0.121185 5 year 0.198572 10 year 0.248331 25 year 0.307521 50 year 0.34852 100 year 0.386815 Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow(cfs) 2 year 1.083522 5 year 1.430277 10 year 1.679058 25 year 2.016028 50 year 2.283995 100 year 2.566915 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #1 Year Predeveloped Mitigated 1949 0.139 1.544 1950 0.166 1.367 1951 0.265 0.902 1952 0.083 0.672 1953 0.067 0.757 1954 0.103 0.880 1955 0.165 1.013 1956 0.133 0.888 1957 0.107 1.101 1958 0.119 0.847 Water Quality Vault 3/16/2017 7:50:01 AM Page 8 1959 0.102 0.842 1960 0.183 1.016 1961 0.100 0.916 1962 0.063 0.720 1963 0.086 0.972 1964 0.122 0.851 1965 0.081 1.135 1966 0.078 0.756 1967 0.186 1.434 1968 0.105 1.659 1969 0.102 1.036 1970 0.082 1.003 1971 0.092 1.226 1972 0.201 1.307 1973 0.089 0.677 1974 0.099 1.192 1975 0.137 1.120 1976 0.098 0.936 1977 0.014 0.904 1978 0.083 1.169 1979 0.050 1.425 1980 0.237 1.910 1981 0.074 1.031 1982 0.153 1.577 1983 0.131 1.148 1984 0.079 0.776 1985 0.047 0.994 1986 0.208 0.924 1987 0.183 1.279 1988 0.072 0.806 1989 0.048 1.261 1990 0.439 2.292 1991 0.233 1.840 1992 0.095 0.827 1993 0.093 0.888 1994 0.031 0.760 1995 0.133 0.922 1996 0.307 1.346 1997 0.237 1.044 1998 0.058 1.023 1999 0.260 2.367 2000 0.092 1.042 2001 0.017 1.126 2002 0.107 1.365 2003 0.160 1.405 2004 0.171 2.240 2005 0.127 0.874 2006 0.143 0.850 2007 0.332 2.144 2008 0.404 1.715 2009 0.188 1.333 Ranked Annual Peaks Ranked Annual Peaks for Predeveloped and Mitigated. POC #1 Rank Predeveloped Mitigated 1 0.4388 2.3669 2 0.4043 2.2921 3 0.3317 2.2395 Water Quality Vault 3/16/2017 7:50:01 AM Page 9 4 0.3073 2.1442 5 0.2648 1.9095 6 0.2600 1.8405 7 0.2372 1.7152 8 0.2366 1.6593 9 0.2328 1.5766 10 0.2077 1.5440 11 0.2010 1.4343 12 0.1885 1.4253 13 0.1861 1.4046 14 0.1833 1.3666 15 0.1827 1.3651 16 0.1709 1.3461 17 0.1656 1.3334 18 0.1647 1.3068 19 0.1599 1.2790 20 0.1535 1.2609 21 0.1426 1.2259 22 0.1395 1.1923 23 0.1375 1.1686 24 0.1329 1.1476 25 0.1327 1.1348 26 0.1313 1.1261 27 0.1268 1.1198 28 0.1217 1.1014 29 0.1189 1.0443 30 0.1071 1.0421 31 0.1071 1.0362 32 0.1047 1.0305 33 0.1031 1.0231 34 0.1020 1.0162 35 0.1019 1.0127 36 0.1005 1.0029 37 0.0987 0.9939 38 0.0982 0.9719 39 0.0950 0.9364 40 0.0928 0.9245 41 0.0924 0.9220 42 0.0924 0.9158 43 0.0891 0.9043 44 0.0858 0.9020 45 0.0831 0.8882 46 0.0830 0.8882 47 0.0818 0.8797 48 0.0809 0.8735 49 0.0791 0.8510 50 0.0778 0.8499 51 0.0743 0.8466 52 0.0724 0.8419 53 0.0671 0.8269 54 0.0625 0.8059 55 0.0580 0.7759 56 0.0502 0.7604 57 0.0479 0.7574 58 0.0469 0.7560 59 0.0311 0.7202 60 0.0166 0.6766 61 0.0144 0.6718 Water Quality Vault 3/16/2017 7:50:01 AM Page 10 Water Quality Vault 3/16/2017 7:50:01 AM Page 11 Duration Flows Flow(cfs)Predev Mit Percentage Pass/Fail 0.0606 17464 104399 597 Fail 0.0635 15729 99715 633 Fail 0.0664 14245 95308 669 Fail 0.0693 12915 91266 706 Fail 0.0722 11659 87416 749 Fail 0.0751 10560 83844 793 Fail 0.0780 9576 80507 840 Fail 0.0810 9007 78326 869 Fail 0.0839 8252 75160 910 Fail 0.0868 7533 72209 958 Fail 0.0897 6872 69385 1009 Fail 0.0926 6290 66626 1059 Fail 0.0955 5803 64145 1105 Fail 0.0984 5369 61621 1147 Fail 0.1013 4964 59268 1193 Fail 0.1042 4596 56980 1239 Fail 0.1071 4254 54841 1289 Fail 0.1100 3955 52830 1335 Fail 0.1129 3745 51547 1376 Fail 0.1159 3467 49622 1431 Fail 0.1188 3195 47783 1495 Fail 0.1217 2967 46071 1552 Fail 0.1246 2744 44425 1618 Fail 0.1275 2513 42906 1707 Fail 0.1304 2344 41387 1765 Fail 0.1333 2152 39933 1855 Fail 0.1362 1986 38564 1941 Fail 0.1391 1830 37302 2038 Fail 0.1420 1702 35997 2114 Fail 0.1449 1622 35142 2166 Fail 0.1478 1485 33923 2284 Fail 0.1508 1352 32746 2422 Fail 0.1537 1252 31634 2526 Fail 0.1566 1163 30629 2633 Fail 0.1595 1094 29623 2707 Fail 0.1624 1024 28640 2796 Fail 0.1653 958 27698 2891 Fail 0.1682 889 26843 3019 Fail 0.1711 827 25966 3139 Fail 0.1740 760 25196 3315 Fail 0.1769 737 24640 3343 Fail 0.1798 686 23849 3476 Fail 0.1827 637 23185 3639 Fail 0.1857 598 22458 3755 Fail 0.1886 562 21688 3859 Fail 0.1915 510 20952 4108 Fail 0.1944 475 20281 4269 Fail 0.1973 429 19652 4580 Fail 0.2002 389 19047 4896 Fail 0.2031 356 18437 5178 Fail 0.2060 328 17877 5450 Fail 0.2089 307 17500 5700 Fail 0.2118 277 16955 6120 Fail 0.2147 250 16472 6588 Fail Water Quality Vault 3/16/2017 7:50:01 AM Page 12 0.2176 224 15995 7140 Fail 0.2206 202 15505 7675 Fail 0.2235 179 15083 8426 Fail 0.2264 154 14651 9513 Fail 0.2293 132 14183 10744 Fail 0.2322 119 13744 11549 Fail 0.2351 104 13334 12821 Fail 0.2380 95 12934 13614 Fail 0.2409 89 12690 14258 Fail 0.2438 78 12324 15800 Fail 0.2467 69 11991 17378 Fail 0.2496 62 11631 18759 Fail 0.2525 54 11325 20972 Fail 0.2555 47 11037 23482 Fail 0.2584 39 10735 27525 Fail 0.2613 31 10442 33683 Fail 0.2642 25 10151 40604 Fail 0.2671 22 9839 44722 Fail 0.2700 21 9685 46119 Fail 0.2729 18 9417 52316 Fail 0.2758 14 9178 65557 Fail 0.2787 13 8949 68838 Fail 0.2816 10 8737 87370 Fail 0.2845 7 8489 121271 Fail 0.2874 7 8252 117885 Fail 0.2904 7 8004 114342 Fail 0.2933 6 7788 129800 Fail 0.2962 6 7608 126800 Fail 0.2991 6 7411 123516 Fail 0.3020 6 7294 121566 Fail 0.3049 6 7127 118783 Fail 0.3078 6 6953 115883 Fail 0.3107 5 6785 135700 Fail 0.3136 5 6628 132560 Fail 0.3165 5 6438 128760 Fail 0.3194 5 6271 125419 Fail 0.3223 5 6111 122219 Fail 0.3253 5 5950 119000 Fail 0.3282 4 5792 144800 Fail 0.3311 4 5630 140750 Fail 0.3340 3 5533 184433 Fail 0.3369 3 5384 179466 Fail 0.3398 3 5274 175800 Fail 0.3427 3 5148 171600 Fail 0.3456 3 5014 167133 Fail 0.3485 3 4911 163700 Fail The development has an increase in flow durations from 1/2 Predeveloped 2 year flow to the 2 year flow or more than a 10% increase from the 2 year to the 50 year flow. The development has an increase in flow durations for more than 50% of the flows for the range of the duration analysis. Water Quality Vault 3/16/2017 7:50:01 AM Page 13 Water Quality Water Quality BMP Flow and Volume for POC #1 On-line facility volume:0.3173 acre-feet On-line facility target flow:0.372 cfs. Adjusted for 15 min:0.372 cfs. Off-line facility target flow:0.2057 cfs. Adjusted for 15 min:0.2057 cfs. Water Quality Vault 3/16/2017 7:50:01 AM Page 14 LID Report Water Quality Vault 3/16/2017 7:50:04 AM Page 15 Model Default Modifications Total of 0 changes have been made. PERLND Changes No PERLND changes have been made. IMPLND Changes No IMPLND changes have been made. Water Quality Vault 3/16/2017 7:50:04 AM Page 16 Appendix Predeveloped Schematic Water Quality Vault 3/16/2017 7:50:04 AM Page 17 Mitigated Schematic Water Quality Vault 3/16/2017 7:50:04 AM Page 18 Predeveloped UCI File Water Quality Vault 3/16/2017 7:50:04 AM Page 19 Mitigated UCI File Water Quality Vault 3/16/2017 7:50:04 AM Page 20 Predeveloped HSPF Message File Water Quality Vault 3/16/2017 7:50:04 AM Page 21 Mitigated HSPF Message File Water Quality Vault 3/16/2017 7:50:04 AM Page 22 Disclaimer Legal Notice This program and accompanying documentation are provided 'as-is' without warranty of any kind. The entire risk regarding the performance and results of this program is assumed by End User. Clear Creek Solutions Inc. and the governmental licensee or sublicensees disclaim all warranties, either expressed or implied, including but not limited to implied warranties of program and accompanying documentation. In no event shall Clear Creek Solutions Inc. be liable for any damages whatsoever (including without limitation to damages for loss of business profits, loss of business information, business interruption, and the like) arising out of the use of, or inability to use this program even if Clear Creek Solutions Inc. or their authorized representatives have been advised of the possibility of such damages. Software Copyright © by : Clear Creek Solutions, Inc. 2005-2017; All Rights Reserved. Clear Creek Solutions, Inc. 6200 Capitol Blvd. Ste F Olympia, WA. 98501 Toll Free 1(866)943-0304 Local (360)943-0304 www.clearcreeksolutions.com Site Planning Civil Engineering Project Management Land Development Consulting APPENDIX C PROJECT SITE AND UPSTREAM LAND USE SUMMARIES Lot Total Area (SF) Assumed % Impervious Imp. Coverage (SF) Lot BMP Target Surface Area (SF) Lot 1 7930 55%4361.5 793 Lot 2 7825 55%4303.75 782.5 Lot 3 7018 55%3859.9 701.8 Lot 4 7549 55%4151.95 754.9 Lot 5 7055 55%3880.25 705.5 Lot 6 8529 55%4690.95 852.9 Lot 7 7297 55%4013.35 729.7 Lot 8 7181 55%3949.55 718.1 Lot 9 7670 55%4218.5 767 Lot 10 7021 55%3861.55 702.1 Lot 11 7021 55%3861.55 702.1 Lot 12 7021 55%3861.55 702.1 Lot 13 7172 55%3944.6 717.2 Lot 14 7579 55%4168.45 757.9 Lot 15 7579 55%4168.45 757.9 Lot 16 7579 55%4168.45 757.9 Lot 17 8969 55%4932.95 896.9 ROW 49093 -29200 S1 3381 -210 S2 6488 -0 Total 186957 99807.25 37391.4 Basin Total Lot Area  (SF)Assumed % ImperviousImp. Lot CoverageTotal ROW AreaAssumed % ImperviousImp. ROW CoverageTotal Imp. CoverageProject Basin 192535 55% 105894 ‐ ‐ ‐ 105894Basin A1196084 55% 107846 9574 90% 8617 116463Basin A2373779 55% 205578 68266 90% 61439 267018Basin A3394359 55% 216897 74948 90% 67453 284351Basin A4116495 55% 64072 17527 90% 15774 79847Basin A556408 55% 31024 17016 90% 15314 46339Basin BNSF 19501 ‐ 17859 ‐ ‐ ‐ 17859Tributary Basin 2300 55% 1265 ‐ ‐ ‐ 1265Total 1158926 644542.75 187331 168597.9 813140.65Project Basin 192535 105,894 86,641 2.43 1.99 2.26 2.87Basin A1205658 116,463 89,195 2.67 2.05 2.45 3.11Basin A2442045 267,018 175,027 6.13 4.02 5.78 6.90Basin A3469307 284,351 184,956 6.53 4.25 5.82 7.34Basin A4134022 79,847 54,175 1.83 1.24 1.64 2.07Basin A573424 46,339 27,085 1.06 0.62 0.93 1.17Basin B 19501 17,860 1,641 0.41 0.37 0.39 0.50Ditch Tributary Basin 2300 1,265 1,035 0.03 0.02 0.03 0.04Total 1,536,492 919,036 618,721 21.07 14.54 19.30 24.00WWHM Model Inputs/OutputsImpervious Area CalulationsModeled Grass Area (AC)Q‐25yr Q‐100yr LotTotal Area (SF)Modeled Impervious Area (SF)Modeled Grass Area (SF)Modeled Impervious Area (AC) Site Planning Civil Engineering Project Management Land Development Consulting APPENDIX D STORMFILTER PARAMETERS SUMMARY Size and Cost Estimate 11835 NE Glenn Widing Dr., Portland OR 97220 Toll-free: 800.548.4667 Fax: 800.561.1271 ©2012 Contech Engineered Solutions LLC www.conteches.com Page 1 of 1 TS-P027 Prepared by Mike Gillette on December 7, 2016 Kennydale Assemblage – Stormwater Treatment System Renton, WA Information provided:  Presiding agency = City of Renton Structure ID SFV  Water Quality Flow Rate (cfs) 0.206  Peak Flow Rate (cfs) 2.57  Number of cartridges 9  Cartridge flow rate (gpm) 11.25  Media type ZPG  Structure size 8’x11’  Peak Diversion  Vault  Approximate Price $45,000   Assumptions:  Media = ZPG cartridges  Cartridge flow rate = 11.25 gpm  Head required for cartridge to activate = 3.05’ minimum Size and cost estimates: The StormFilter is a flow-based system, and is therefore sized by calculating the peak water quality flow rate associated with the design storm. The water quality flow rate was calculated by the consulting engineer using WWHM and was provided to Contech Engineered Solutions LLC for the purposes of developing this estimate. The StormFilter for this site was sized based on the above water quality flow rate. To accommodate this flow rate, Contech Engineered Solutions recommends using a StormFilter Peak Diversion Vault with (9) – 27” cartridges (see attached detail). The estimated cost of this system is shown in the above table; this estimate includes the complete system delivered to the job site. The final system cost will depend on the actual depth of the unit and whether extras like doors rather than castings are specified. The contractor is responsible for setting the StormFilter Manhole and all external plumbing. Typically the precast StormFilters have internal bypass capacities of 1.8 cfs. Since the peak flow rate is expected to exceed 1.8 cfs, a peak diversion StormFilter system was recommended. This system has an internal weir in the inlet/outlet bay, and is able to bypass the peak flow specified above. The vault is designed to meet the Department of Ecology requirement for offline sizing; the weir is designed so that no more than 110% of the offline water quality flow can enter the cartridge bay, and all excess flows will bypass the cartridges. CONTECH Stormwater Solutions Inc. Engineer:MSG Date 12/7/2016 Site Information Project Name Kennydale Assemblage Project State Washington Project Location Renton Drainage Area, Ad 4.07 ac Impervious Area, Ai 2.10 ac Pervious Area, Ap 1.97 % Impervious 52% Runoff Coefficient, Rc 0.51 Water quality flow 0.206 cfs Peak storm flow 2.57 cfs Filter System Filtration brand StormFilter Cartridge height 27 in Specific Flow Rate 1.00 gpm/ft2 Flow rate per cartridge 11.3 gpm SUMMARY Number of Cartridges 9 Determining Number of Cartridges for Flow Based Systems ©2006 CONTECH Stormwater Solutions contechstormwater.com 1 of 1 Size and Cost Estimate 11835 NE Glenn Widing Dr., Portland OR 97220 Toll-free: 800.548.4667 Fax: 800.561.1271 ©2015 Contech Engineered Solutions LLC www.conteches.com Page 1 of 1 Prepared by Mike Gillette on December 7, 2016 Kennydale Assemblage Renton, WA Information Provided: Structure ID Filterra  Total basin area 0.220 ac  Impervious area 0.182 ac  Filterra model FTIBC  Outlet pipe size 6”  Media bay dimensions 4’ x 4’  Total inside dimensions 6’ x 4’  Approximate Price $14,800   System Parameters:  Filterra Media Flow Rate = 100 in/hr  Treatment type = Basic  Depth Required from Rim to Outlet = 48” min – 65” max  Reviewing agency = City of Renton Size and Cost Estimate: The Filterra system for this site was sized using WWHM. Per the Department of Ecology approval, the total basin area, percent impervious area, and site location were used to size the system. Contech Engineered Solutions recommends using the Filterra Internal Bypass – Curb (FTIBC) system to provide enhanced treatment. The estimated cost of this system is shown above, and this includes the complete system delivered to the job site. This estimate assumes that the system is delivered with all components pre-installed. The contractor is responsible for setting the Filterra and connecting all external plumbing. The Filterra Internal Bypass – Curb (FTIBC) with a 6” bypass pipe has an internal bypass capacity of 1.3 cfs. Since the peak discharge from the drainage area is not expected to exceed this rate, a high flow bypass isn’t required. Size and Cost Estimate 11835 NE Glenn Widing Dr., Portland OR 97220 Toll-free: 800.548.4667 Fax: 800.561.1271 ©2012 Contech Engineered Solutions LLC www.conteches.com Page 1 of 1 TS-P027 Prepared by Mike Gillette on April 26, 2017 Kennydale Assemblage – Stormwater Treatment System Renton, WA Information provided: • Presiding agency = City of Renton Structure ID SFCB Water Quality Flow Rate (cfs) 0.01 Peak Flow Rate (cfs) 0.28 Number of cartridges 1 Cartridge flow rate (gpm) 7.5 Media type ZPG Structure size Steel Catch Basin Approximate Price $5,500 Assumptions: • Media = ZPG cartridges • Drop required from rim to outlet = 2.3’ minimum for 18” cartridges Size and cost estimates: The StormFilter is a flow-based system, and is therefore sized by calculating the peak water quality flow rate associated with the design storm. The water quality flow rates were calculated by the consulting engineer using WWHM and were provided to Contech Engineered Solutions LLC for the purposes of developing this estimate. The StormFilter for this site was sized based on the above water quality flow rate. To accommodate this flow rate, Contech Engineered Solutions recommends using a catch basin StormFilter (see attached detail). The estimated cost of this system is shown in the above table; this estimate includes the complete system delivered to the job site. The final system cost will depend on the actual depth of the units and whether extras like doors rather than castings are specified. The contractor is responsible for setting the catch basin StormFilter and all external plumbing. Typically the catch basin StormFilters have internal bypass capacities of 1.0 cfs. Since the peak discharge in the basin is not expected to exceed this rate, a high-flow bypass upstream of the StormFilter system is not required. CONTECH Stormwater Solutions Inc. Engineer:MSG Date 4/26/2017 Site Information SFCB Project Name Kennydale Assemblage Project State Washington Project Location Renton Drainage Area, Ad 0.327 ac Impervious Area, Ai 0.290 ac Pervious Area, Ap 0.04 % Impervious 89% Runoff Coefficient, Rc 0.85 Water quality flow 0.010 cfs Peak storm flow 0.281 cfs Filter System Filtration brand StormFilter Cartridge height 18 in Specific Flow Rate 1.00 gpm/ft2 Flow rate per cartridge 7.5 gpm SUMMARY Number of Cartridges 1 Determining Number of Cartridges for Flow Based Systems ©2006 CONTECH Stormwater Solutions contechstormwater.com 1 of 1 Size and Cost Estimate 11835 NE Glenn Widing Dr., Portland OR 97220 Toll-free: 800.548.4667 Fax: 800.561.1271 ©2012 Contech Engineered Solutions LLC www.conteches.com Page 1 of 1 TS-P027 Prepared by Mike Gillette on April 27, 2017 Kennydale Assemblage – Stormwater Treatment System Renton, WA Information provided: • Presiding agency = City of Renton Structure ID Presettling CDS Water Quality Flow Rate 0.22 cfs Peak Flow Rate 2.72 cfs CDS Model 2015-4 CDS Treatment capacity (cfs) 0.7 Structure size 48” Manhole Approximate Price $9,000 CDS System Sizing: The CDS Stormwater Treatment System is a high-performance hydrodynamic separator. Using patented continuous deflective separation technology, the CDS system screens, separates and traps debris, sediment, and oil and grease from stormwater runoff. The indirect screening capability of the system allows for 100% removal of floatables and neutrally buoyant material without blinding. Flow and screening controls physically separate captured solids, preventing re-suspension and release of previously trapped pollutants The CDS model was selected based on WADOE GULD approval using a 2400 micron screen. Maintenance: Like any stormwater best management practice, the CDS system requires regular inspection and maintenance to ensure optimal performance. Maintenance frequency will be driven by site conditions. Quarterly visual inspections are recommended, at which time the accumulation of pollutants can be determined. On average, the CDS system requires annual removal of accumulated pollutants. Site Planning Civil Engineering Project Management Land Development Consulting APPENDIX E CONVEYANCE CALCULATIONS APPENDIX C.1 - CPH Rational Calculations 10 yr 25 yr 100yr Project Name: Senza Lakeview aR 2.44 2.66 2.61 bR 0.64 0.65 0.63 PR 2.9 3.4 3.9 Description: Rational calculation spreadsheet for backwater analysis CB140 4932 0.11 0.90 0.08 0.25 0.03 0.72 0.02 17.00 2.08 50.00 0.40 6.30 0.82 3.19 0.11 0.26 6.67 CB135 1 0.00 0.90 0.00 0.25 0.00 0.72 0.02 17.00 2.08 50.00 0.40 6.30 0.82 3.19 0.00 0.00 2.71 CB130 1 0.00 0.90 0.00 0.25 0.00 0.72 0.02 17.00 2.08 50.00 0.40 6.30 0.82 3.19 0.00 0.00 2.71 CB125 8476 0.19 0.90 0.14 0.25 0.05 0.72 0.02 17.00 2.08 50.00 0.40 6.30 0.82 3.19 0.19 0.45 2.71 CB120 36488 0.84 0.90 0.60 0.25 0.23 0.72 0.02 17.00 2.08 50.00 0.40 6.30 0.82 3.19 0.84 1.92 2.27 CB115 6601 0.15 0.90 0.11 0.25 0.04 0.72 0.02 17.00 2.08 50.00 0.40 6.30 0.82 3.19 0.15 0.35 0.35 EXIST. CB 4 13691 0.31 0.90 0.23 0.25 0.09 0.72 0.02 17.00 2.08 50.00 0.40 6.30 0.82 3.19 0.31 0.72 1.29 STORMFILTER CB 4698 0.11 0.90 0.08 0.25 0.03 0.72 0.02 17.00 2.08 50.00 0.40 6.30 0.82 3.19 0.11 0.25 0.56 CB205 4589 0.11 0.90 0.08 0.25 0.03 0.72 0.02 17.00 2.40 50.00 0.35 6.30 0.82 3.19 0.11 0.24 0.32 CB210 1445 0.03 0.90 0.02 0.25 0.01 0.72 0.02 17.00 2.40 50.00 0.35 6.30 0.82 3.19 0.03 0.08 0.08 CB75 924 0.02 0.90 0.02 0.25 0.01 0.72 0.01 17.00 1.20 50.00 0.69 6.30 0.82 3.19 0.02 0.05 3.70 CB70 7516 0.17 0.90 0.12 0.25 0.05 0.72 0.01 17.00 1.20 50.00 0.69 6.30 0.82 3.19 0.17 0.40 1.85 CB65 381 0.01 0.90 0.01 0.25 0.00 0.72 0.02 17.00 2.25 50.00 0.37 6.30 0.82 3.19 0.01 0.02 1.46 CB60 2791 0.06 0.90 0.05 0.25 0.02 0.72 0.02 17.00 2.25 50.00 0.37 6.30 0.82 3.19 0.06 0.15 1.44 CB55 10 0.00 0.90 0.00 0.25 0.00 0.72 0.02 17.00 2.25 50.00 0.37 6.30 0.82 3.19 0.00 0.00 0.00 EXIST. CB 2 8577 0.20 0.90 0.14 0.25 0.06 0.72 0.03 17.00 2.69 50.00 0.31 6.30 0.82 3.19 0.20 0.45 2.61 CB145 1 0.00 0.90 0.00 0.25 0.00 0.72 0.03 17.00 2.69 50.00 0.31 6.30 0.82 3.19 0.00 0.00 2.16 CB20 7792 0.18 0.90 0.13 0.25 0.05 0.72 0.03 17.00 2.69 50.00 0.31 6.30 0.82 3.19 0.18 0.41 2.16 CB15 21306 0.49 0.90 0.35 0.25 0.14 0.72 0.03 17.00 2.69 50.00 0.31 6.30 0.82 3.19 0.49 1.12 1.75 CB10 11561 0.27 0.90 0.19 0.25 0.07 0.72 0.03 17.00 2.69 50.00 0.31 6.30 0.82 3.19 0.27 0.61 0.63 CB5 405 0.01 0.90 0.01 0.25 0.00 0.72 0.03 17.00 2.69 50.00 0.31 6.30 0.82 3.19 0.01 0.02 0.02 CB76 16900 0.39 0.90 0.28 0.25 0.11 0.72 0.01 17.00 1.20 50.00 0.69 6.30 0.82 3.19 0.39 0.89 0.89 CB71 17251 0.40 0.90 0.29 0.25 0.11 0.72 0.02 17.00 2.08 50.00 0.40 6.30 0.82 3.19 0.40 0.91 0.91 CB61 24523 0.56 0.90 0.41 0.25 0.16 0.72 0.02 17.00 2.08 50.00 0.40 6.30 0.82 3.19 0.56 1.29 1.29 INTAKE #1 10143 0.23 0.90 0.17 0.25 0.07 0.72 0.02 17.00 2.08 50.00 0.40 6.30 0.82 3.19 0.23 0.53 0.53 CB134261 11034 0.25 0.90 0.18 0.25 0.07 0.72 0.02 17.00 2.08 50.00 0.40 6.30 0.82 3.19 0.25 0.58 0.58 Ditch 2300 0.05 0.90 0.04 0.25 0.01 0.72 0.02 17.00 2.08 50.00 0.40 6.30 0.82 3.19 0.05 0.12 0.12 CPH Backwater Spreadsheet CPH Backwater Spreadsheet CPH Backwater Spreadsheet Velocity (fps) Length of Flowpath (feet) CPH Project No.: 0139-15-001 Basin / Subbasin C1 A1 (acres)C2 Flowpath Slope (ft/ft) A2 (acres)CcSFAC Total Area Qf/Qt CPH Backwater Spreadsheet At (acres) Q Basin (cfs) Travel Time (minutes) Travel Time Used (minutes) IRiR CPH Backwater Spreadsheet CPH Backwater Spreadsheet CPH Backwater Spreadsheet CPH Backwater Spreadsheet Qt Total (cfs) kR (KCSWDM Table 3.2.1.C) Slope of Pipe (ft/ft) Q Ratio Length of Pipe (feet) Diameter of Pipe (inches) Manning's Value "n" Velocity Full (fps) (NOAA Atlas - Isopluvial Maps: Figures 27,28,30) Qf Full (cfs) CPH Backwater Spreadsheet CPH Backwater Spreadsheet CPH Backwater Spreadsheet CPH Backwater Spreadsheet To CB CPH Backwater Spreadsheet CPH Backwater Spreadsheet CPH Backwater Spreadsheet CPH Backwater Spreadsheet CPH Backwater Spreadsheet CPH Backwater Spreadsheet CPH Backwater Spreadsheet CPH Backwater Spreadsheet CPH Backwater Spreadsheet CPH Backwater Spreadsheet CPH Backwater Spreadsheet CPH Backwater Spreadsheet CPH Backwater Spreadsheet CPH Backwater Spreadsheet CPH Backwater Spreadsheet Senza Lakeview Rational_13915001 CPH Consultants 2/7/2018 1 Appendix C.2 - CPH Backwater Calculations 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Design Flow Q Length Pipe Size Manning's n Downstream Invert Elevation Upstream Inlet Elevation Pipe Slope Barrel Area Barrel Velocity Barrel Velocity Head TW Elevation Barrel Perimeter Friction Slope Friction Loss Entrance HGL Elevation Entrance Loss Coefficient Entrance Head Loss Exit Head Loss Outlet Control Elevation dc/D Critical Depth Critical Velocity Inlet Control Elevation Approach Velocity Head Kb Bend Head Loss Q3/Q1 Kj Junction Head Loss Head Water Rim Elevation Overflow? D/S CB U/S CB (cfs)(ft)(in)(ft)(ft)(ft/ft)(sq. ft)(fps)(ft)(ft)(ft)Sf (ft)(ft)ke (ft)(ft)(ft)(ft)(fps)(ft)(ft)(ft)(%)(ft)(ft)(ft) Vault CB141 6.77 5.79 18 0.012 49.50 49.91 0.071 1.77 3.83 0.23 50.62 4.71 0.00 0.02 51.41 0.50 0.11 0.23 51.75 0.57 0.86 5.25 50.92 0.23 0.00 0.000 0%0.00 0.00 51.52 54.00 Contained CB141 CB140 6.77 8.2 18 0.012 49.91 50.50 0.072 1.77 3.83 0.23 51.52 4.71 0.00 0.03 52.00 0.50 0.11 0.23 52.34 0.57 0.86 5.25 51.51 0.18 0.00 0.000 0%0.00 0.00 52.16 54.90 Contained CB140 CB135 2.71 49.44 12 0.012 51.00 51.88 0.018 0.79 3.45 0.18 52.16 3.14 0.00 0.24 52.88 0.50 0.09 0.18 53.16 0.57 0.57 4.28 52.94 0.18 0.00 0.000 0%0.00 0.00 52.97 55.38 Contained CB135 CB130 2.71 88.01 12 0.012 51.88 56.10 0.048 0.79 3.45 0.18 52.97 3.14 0.00 0.43 57.10 0.50 0.09 0.18 57.38 0.57 0.57 4.28 57.15 0.18 0.00 0.000 0%0.00 0.00 57.19 65.45 Contained CB130 CB125 2.71 38.7 12 0.012 56.10 61.65 0.143 0.79 3.45 0.18 57.19 3.14 0.00 0.19 62.65 0.50 0.09 0.18 62.93 0.57 0.57 4.28 62.65 0.13 0.00 0.000 0%0.00 0.00 62.80 65.36 Contained CB125 CB120 2.27 18.51 12 0.012 61.65 61.85 0.011 0.79 2.89 0.13 62.80 3.14 0.00 0.06 62.86 0.50 0.06 0.13 63.06 0.57 0.57 4.28 62.87 0.00 0.00 0.000 0%0.00 0.00 63.05 65.35 Contained CB120 CB115 0.35 29.88 12 0.012 61.85 66.05 0.141 0.79 0.45 0.00 63.05 3.14 0.00 0.00 67.05 0.50 0.00 0.00 67.05 0.57 0.57 4.28 66.84 0.00 0.00 0.000 0%0.00 0.00 67.05 68.81 Contained CB140 CB75 3.70 139.01 12 0.012 51.00 65.43 0.104 0.79 4.71 0.34 51.52 3.14 0.01 1.26 66.43 0.50 0.17 0.34 66.95 0.57 0.57 4.28 67.15 0.09 0.00 0.000 0%0.00 0.00 67.06 69.25 Contained CB75 CB70 1.85 22.62 12 0.012 65.43 67.00 0.069 0.79 2.36 0.09 67.06 3.14 0.00 0.05 68.00 0.50 0.04 0.09 68.13 0.57 0.57 4.28 67.94 0.05 0.00 0.000 0%0.00 0.00 68.08 69.97 Contained CB70 CB65 1.44 82.12 12 0.012 67.00 71.09 0.050 0.79 1.83 0.05 68.08 3.14 0.00 0.11 72.09 0.50 0.03 0.05 72.17 0.57 0.57 4.28 72.00 0.05 0.00 0.000 0%0.00 0.00 72.12 74.05 Contained CB65 CB60 1.44 54.9 12 0.012 71.09 76.29 0.095 0.79 1.83 0.05 72.12 3.14 0.00 0.08 77.29 0.50 0.03 0.05 77.37 0.57 0.57 4.28 77.18 0.00 0.00 0.000 0%0.00 0.00 77.37 79.37 Contained CB60 CB55 0.00 86.64 12 0.012 76.29 84.90 0.099 0.79 0.00 0.00 77.37 3.14 0.00 0.00 85.90 0.50 0.00 0.00 85.90 0.57 0.57 4.28 85.71 0.00 0.00 0.000 0%0.00 0.00 85.90 88.22 Contained CB145 CB20 4.77 6.66 12 0.012 44.28 44.32 0.006 0.79 6.07 0.57 45.62 3.14 0.02 0.10 45.72 0.50 0.29 0.57 46.58 0.57 0.57 4.28 46.90 0.48 0.00 0.000 0%0.00 0.00 46.42 48.33 Contained CB20 CB15 4.36 84.11 12 0.012 44.32 45.18 0.010 0.79 5.55 0.48 46.42 3.14 0.01 1.06 47.48 0.50 0.24 0.48 48.20 0.57 0.57 4.28 47.42 0.26 0.00 0.000 0%0.00 0.00 47.93 48.97 Contained CB15 CB10 3.24 150.99 12 0.012 45.18 47.00 0.012 0.79 4.13 0.26 47.93 3.14 0.01 1.05 48.99 0.50 0.13 0.26 49.38 0.57 0.57 4.28 48.48 0.17 0.00 0.000 0%0.00 0.00 49.21 50.59 Contained CB10 CB5 2.63 147.6 12 0.012 47.00 48.15 0.008 0.79 3.35 0.17 49.21 3.14 0.00 0.68 49.89 0.50 0.09 0.17 50.15 0.57 0.57 4.28 49.21 0.00 0.00 0.000 0%0.00 0.00 50.15 51.25 Contained CB134263 EXIST. CB4 1.29 8.8 12 0.012 93.71 95.02 0.149 0.79 1.64 0.04 26.80 3.14 0.00 0.01 96.02 0.50 0.02 0.04 96.08 0.57 0.57 4.28 95.87 0.01 0.00 0.000 0%0.00 0.00 96.07 98.41 Contained EXIST. CB4 STORMFILTER CB 0.56 21.96 12 0.012 95.02 96.75 0.079 0.79 0.71 0.01 96.07 3.14 0.00 0.00 97.75 0.50 0.00 0.01 97.76 0.57 0.57 4.28 97.59 0.00 0.00 0.000 0%0.00 0.00 97.76 100.68 Contained STORMFILTER CB CB205 0.32 136.76 12 0.012 96.75 105.34 0.063 0.79 0.41 0.00 97.76 3.14 0.00 0.01 106.34 0.50 0.00 0.00 106.34 0.57 0.57 4.28 106.17 0.00 0.00 0.000 0%0.00 0.00 106.34 114.00 Contained CB205 CB210 0.08 145.5 12 0.012 105.34 114.48 0.063 0.79 0.10 0.00 106.34 3.14 0.00 0.00 115.48 0.50 0.00 0.00 115.48 0.57 0.57 4.28 115.30 0.00 0.00 0.000 0%0.00 0.00 115.48 120.50 Contained CB75 CB76 0.89 17.8 12 0.012 65.43 65.52 0.005 0.79 1.13 0.02 67.06 3.14 0.00 0.01 67.07 0.50 0.01 0.02 67.10 0.57 0.57 4.28 66.41 0.00 0.00 0.000 0%0.00 0.00 67.10 68.95 Contained CB75 CB71 0.91 25.74 12 0.012 65.43 66.07 0.025 0.79 1.16 0.02 67.06 3.14 0.00 0.01 67.07 0.50 0.01 0.02 67.10 0.57 0.57 4.28 66.95 0.00 0.00 0.000 0%0.00 0.00 67.10 69.13 Contained CB60 CB61 1.29 18.49 12 0.012 76.29 76.71 0.023 0.79 1.64 0.04 77.37 3.14 0.00 0.02 77.71 0.50 0.02 0.04 77.77 0.57 0.57 4.28 77.63 0.00 0.00 0.000 0%0.00 0.00 77.77 79.37 Contained OUTLET CB114575 24.84 6 30 0.012 18.55 18.87 0.053 4.91 5.06 0.40 18.55 7.85 0.00 0.02 21.37 0.50 0.20 0.40 21.97 0.57 1.43 6.77 19.89 0.40 0.00 0.000 0%0.00 0.00 21.57 23.77 Contained CB114575 CB114824 24.84 66 30 0.012 18.87 18.81 -0.001 4.91 5.06 0.40 21.57 7.85 0.00 0.20 21.77 0.50 0.20 0.40 22.37 0.57 1.43 6.77 19.86 0.37 0.00 0.000 0%0.00 0.00 22.00 24.61 Contained CB114824 CB114823 24.04 40 30 0.012 18.81 18.78 -0.001 4.91 4.90 0.37 22.00 7.85 0.00 0.12 22.11 0.50 0.19 0.37 22.67 0.57 1.43 6.77 19.82 0.37 0.00 0.000 0%0.00 0.00 22.30 24.63 Contained CB114823 CB114822 24.00 40 30 0.012 18.78 18.84 0.001 4.91 4.89 0.37 22.30 7.85 0.00 0.12 22.42 0.50 0.19 0.37 22.97 0.57 1.43 6.77 19.88 0.37 0.00 0.000 0%0.00 0.00 22.60 24.54 Contained CB114822 CB114573 24.00 81 30 0.012 19.00 19.15 0.002 4.91 4.89 0.37 22.60 7.85 0.00 0.23 22.84 0.50 0.19 0.37 23.39 0.57 1.43 6.77 20.19 0.91 0.00 0.000 0%0.00 0.00 22.49 25.85 Contained CB114573 CB114828 24.00 85 24 0.012 19.23 24.35 0.060 3.14 7.64 0.91 22.49 6.28 0.01 0.81 26.35 0.50 0.45 0.91 27.71 0.57 1.14 6.06 26.47 0.91 0.00 0.000 0%0.00 0.00 26.80 29.50 Contained CB114828 CB310 24.00 26.83 24 0.012 24.40 26.60 0.082 3.14 7.64 0.91 26.80 6.28 0.01 0.26 28.60 0.50 0.45 0.91 29.96 0.57 1.14 6.06 28.71 0.90 0.00 0.000 0%0.00 0.00 29.06 29.91 Contained CB310 CB305 23.96 19.01 24 0.012 26.60 27.50 0.047 3.14 7.63 0.90 29.06 6.28 0.01 0.18 29.50 0.50 0.45 0.90 30.85 0.57 1.14 6.06 29.62 0.90 0.00 0.000 0%0.00 0.00 29.95 32.50 Contained CB305 CB132959 23.96 50.15 24 0.012 27.50 29.48 0.039 3.14 7.63 0.90 29.95 6.28 0.01 0.48 31.48 0.50 0.45 0.90 32.83 0.57 1.14 6.06 31.61 2.74 0.00 0.000 0%0.00 0.00 30.10 36.12 Contained CB132959 CB134293 23.46 40.73 18 0.012 29.48 40.54 0.272 1.77 13.28 2.74 30.10 4.71 0.04 1.72 42.04 0.50 1.37 2.74 46.15 0.57 0.86 5.25 47.44 0.87 0.00 0.000 0%0.00 0.00 46.58 47.47 Contained CB134293 CB134294 23.46 31.88 24 0.012 40.04 41.45 0.044 3.14 7.47 0.87 46.58 6.28 0.01 0.29 46.87 0.50 0.43 0.87 48.16 0.57 1.14 6.06 43.51 1.57 0.00 0.000 0%0.00 0.00 46.60 48.15 Contained CB134294 CB134295 17.76 34.45 18 0.012 43.34 45.54 0.064 1.77 10.05 1.57 46.60 4.71 0.02 0.83 47.43 0.50 0.78 1.57 49.78 0.57 0.86 5.25 49.77 1.57 0.00 0.000 0%0.00 0.00 48.21 51.43 Contained CB134295 CB134260 17.76 140.45 18 0.012 45.69 61.12 0.110 1.77 10.05 1.57 48.21 4.71 0.02 3.39 62.62 0.50 0.78 1.57 64.97 0.57 0.86 5.25 65.33 1.57 0.00 0.000 0%0.00 0.00 63.76 67.31 Contained CB134260 CB134263 17.76 260.37 18 0.012 61.41 92.95 0.121 1.77 10.05 1.57 63.76 4.71 0.02 6.29 94.45 0.50 0.78 1.57 96.80 0.57 0.86 5.25 97.15 1.52 0.00 0.000 0%0.00 0.00 95.63 98.22 Contained CB134263 CB134265 17.48 40.08 18 0.012 92.54 96.28 0.093 1.77 9.89 1.52 95.63 4.71 0.02 0.94 97.78 0.50 0.76 1.52 100.06 0.57 0.86 5.25 100.38 0.59 0.00 0.000 0%0.00 0.00 99.79 101.44 Contained CB134265 CB134267 10.87 15.83 18 0.012 96.74 98.09 0.085 1.77 6.15 0.59 99.79 4.71 0.01 0.14 99.94 0.50 0.29 0.59 100.82 0.57 0.86 5.25 99.98 0.00 0.00 0.000 0%0.00 0.00 100.82 101.11 Contained CB134294 CB145 14.15 49.28 18 0.012 41.95 43.78 0.037 1.77 8.01 1.00 22.30 4.71 0.02 0.76 45.28 0.50 0.50 1.00 46.77 0.57 0.86 5.25 46.67 1.15 0.00 0.000 0%0.00 0.00 45.62 48.50 Contained CB145 VAULT 6.77 30.97 12 0.012 44.28 46.00 0.056 0.79 8.62 1.15 45.62 3.14 0.03 0.94 47.00 0.50 0.58 1.15 48.73 0.57 0.57 4.28 50.62 0.00 0.00 0.000 0%0.00 0.00 50.62 53.25 Contained CB132959 BNSF INTAKE 0.45 32.65 18 0.012 29.9 36 0.187 1.77 0.25 0.00 21.57 4.71 0.00 0.00 37.50 0.50 0.00 0.00 37.50 0.57 0.86 5.25 36.76 0.00 0.00 0.000 0%0.00 0.00 37.50 40.00 Contained CB134294 CB134447 0.25 30.4 6 0.012 44.82 47.4 0.085 0.20 1.27 0.03 22.30 1.57 0.00 0.05 47.90 0.50 0.01 0.03 47.94 0.57 0.29 3.03 48.29 0.00 0.00 0.000 0%0.00 0.00 48.29 49.00 Contained CB134294 INTAKE #1 (ditch)0.53 39.67 12 0.012 44.7 45.88 0.030 0.79 0.67 0.01 22.30 3.14 0.00 0.01 46.88 0.50 0.00 0.01 46.89 0.57 0.57 4.28 46.74 0.00 0.00 0.000 0%0.00 0.00 46.89 47.50 Contained CB134260 CB134261 0.58 19.66 12 0.012 62.33 63.57 0.063 0.79 0.74 0.01 22.49 3.14 0.00 0.00 64.57 0.50 0.00 0.01 64.58 0.57 0.57 4.28 64.42 0.00 0.00 0.000 0%0.00 0.00 64.58 66.49 Contained D/S BACKWATER (OFFSITE) PIPE SEGMENT DESCRIPTION:100-yr Storm drain conveyance system for Senza Lakeview: Backwater Spreadsheet. PROJECT: DATE: CPH PROJECT No. Senza Lakeview 4/30/2018 0139-15-001 Appendix C.2 - CPH Backwater Calculations 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Design Flow Q Length Pipe Size Manning's n Downstream Invert Elevation Upstream Inlet Elevation Pipe Slope Barrel Area Barrel Velocity Barrel Velocity Head TW Elevation Barrel Perimeter Friction Slope Friction Loss Entrance HGL Elevation Entrance Loss Coefficient Entrance Head Loss Exit Head Loss Outlet Control Elevation dc/D Critical Depth Critical Velocity Inlet Control Elevation Approach Velocity Head Kb Bend Head Loss Q3/Q1 Kj Junction Head Loss Head Water Rim Elevation Overflow? D/S CB U/S CB (cfs)(ft)(in)(ft)(ft)(ft/ft)(sq. ft)(fps)(ft)(ft)(ft)Sf (ft)(ft)ke (ft)(ft)(ft)(ft)(fps)(ft)(ft)(ft)(%)(ft)(ft)(ft) OUTLET CB114575 20.14 6 30 0.012 18.55 18.87 0.053 4.91 4.10 0.26 18.55 7.85 0.00 0.01 21.37 0.50 0.13 0.26 21.76 0.57 1.43 6.77 19.84 0.26 0.00 0.000 0%0.00 0.00 21.50 23.77 Contained CB114575 CB114824 20.14 66 30 0.012 18.87 18.81 -0.001 4.91 4.10 0.26 21.50 7.85 0.00 0.13 21.64 0.50 0.13 0.26 22.03 0.57 1.43 6.77 19.81 0.24 0.00 0.000 0%0.00 0.00 21.79 24.61 Contained CB114824 CB114823 19.34 40 30 0.012 18.81 18.78 -0.001 4.91 3.94 0.24 21.79 7.85 0.00 0.08 21.86 0.50 0.12 0.24 22.22 0.57 1.43 6.77 19.77 0.24 0.00 0.000 0%0.00 0.00 21.98 24.63 Contained CB114823 CB114822 19.30 40 30 0.012 18.78 18.84 0.001 4.91 3.93 0.24 21.98 7.85 0.00 0.07 22.06 0.50 0.12 0.24 22.42 0.57 1.43 6.77 19.83 0.24 0.00 0.000 0%0.00 0.00 22.18 24.54 Contained CB114822 CB114573 19.30 81 30 0.012 19.00 19.15 0.002 4.91 3.93 0.24 22.18 7.85 0.00 0.15 22.33 0.50 0.12 0.24 22.69 0.57 1.43 6.77 20.14 0.59 0.00 0.000 0%0.00 0.00 22.10 25.85 Contained CB114573 CB114828 19.30 85 24 0.012 19.23 24.35 0.060 3.14 6.14 0.59 22.10 6.28 0.01 0.52 26.35 0.50 0.29 0.59 27.23 0.57 1.14 6.06 25.90 0.59 0.00 0.000 0%0.00 0.00 26.64 29.50 Contained CB114828 CB310 19.30 26.83 24 0.012 24.40 26.60 0.082 3.14 6.14 0.59 26.64 6.28 0.01 0.17 28.60 0.50 0.29 0.59 29.48 0.57 1.14 6.06 28.14 0.58 0.00 0.000 0%0.00 0.00 28.89 29.91 Contained CB310 CB305 19.27 19.01 24 0.012 26.60 27.50 0.047 3.14 6.13 0.58 28.89 6.28 0.01 0.12 29.50 0.50 0.29 0.58 30.38 0.57 1.14 6.06 29.06 0.58 0.00 0.000 0%0.00 0.00 29.79 32.50 Contained CB305 CB132959 19.27 50.15 24 0.012 27.50 29.48 0.039 3.14 6.13 0.58 29.79 6.28 0.01 0.31 31.48 0.50 0.29 0.58 32.36 0.57 1.14 6.06 31.04 1.77 0.00 0.000 0%0.00 0.00 30.58 36.12 Contained CB132959 CB134293 18.88 40.73 18 0.012 29.48 40.54 0.272 1.77 10.68 1.77 30.58 4.71 0.03 1.11 42.04 0.50 0.89 1.77 44.70 0.57 0.86 5.25 45.15 0.56 0.00 0.000 0%0.00 0.00 44.59 47.47 Contained CB134293 CB134294 18.88 31.88 24 0.012 40.04 41.45 0.044 3.14 6.01 0.56 44.59 6.28 0.01 0.19 44.78 0.50 0.28 0.56 45.62 0.57 1.14 6.06 42.97 1.04 0.00 0.000 0%0.00 0.00 44.58 48.15 Contained CB134294 CB134295 14.45 34.45 18 0.012 43.34 45.54 0.064 1.77 8.18 1.04 44.58 4.71 0.02 0.55 47.04 0.50 0.52 1.04 48.60 0.57 0.86 5.25 48.51 1.04 0.00 0.000 0%0.00 0.00 47.56 51.43 Contained CB134295 CB134260 14.45 140.45 18 0.012 45.69 61.12 0.110 1.77 8.18 1.04 47.56 4.71 0.02 2.25 62.62 0.50 0.52 1.04 64.18 0.57 0.86 5.25 64.07 1.04 0.00 0.000 0%0.00 0.00 63.14 67.31 Contained CB134260 CB134263 14.45 260.37 18 0.012 61.41 92.95 0.121 1.77 8.18 1.04 63.14 4.71 0.02 4.16 94.45 0.50 0.52 1.04 96.01 0.57 0.86 5.25 95.89 1.00 0.00 0.000 0%0.00 0.00 95.01 98.22 Contained CB134263 CB134265 14.17 40.08 18 0.012 92.54 96.28 0.093 1.77 8.02 1.00 95.01 4.71 0.02 0.62 97.78 0.50 0.50 1.00 99.28 0.57 0.86 5.25 99.14 0.39 0.00 0.000 0%0.00 0.00 98.89 101.44 Contained CB134265 CB134267 8.83 15.83 18 0.012 96.74 98.09 0.085 1.77 5.00 0.39 98.89 4.71 0.01 0.09 99.59 0.50 0.19 0.39 100.17 0.57 0.86 5.25 99.51 0.00 0.00 0.000 0%0.00 0.00 100.17 101.11 Contained PIPE SEGMENT DESCRIPTION:25-yr Storm drain conveyance system for Senza Lakeview: Backwater Spreadsheet. PROJECT: DATE: CPH PROJECT No. Senza Lakeview 4/30/2018 0139-15-001 Site Planning Civil Engineering Project Management Land Development Consulting APPENDIX F OFFISTE ANALYIS TABLE AND DOWNSTEAM PHOTOS OFF-SITE ANALYSIS DRAINAGE SYSTEM TABLE SURFACE WATER DESIGN MANUAL, CORE REQUIREMENT #2 Basin: May Creek Subbasin Name: Subbasin Number: - Drainage Component Type, Name, and Size Drainage Component Description Slope Distance from site discharge Existing Problems Potential Problems Observations of field inspector, resource reviewer, or resident Type: sheet flow, swale, stream, channel, pipe, pond; Size: diameter, surface area drainage basin, vegetation, cover, depth, type of sensitive area, volume % ¼ ml = 1,320 ft. constrictions, under capacity, ponding, overtopping, flooding, habitat or organism destruction, scouring, bank sloughing, sedimentation, incision, other erosion tributary area, likelihood of problem, overflow pathways, potential impacts Sheet Flow Shallow, concentrated flows (red arrows in Figure 7) 0-15 0’ - 670’ None Unable to follow flow path as sheet flow is carried throughout multiple downstream private properties Roadside Ditch Grass lined ditch 0-0.5 0 – 390’ None No problems observed Type 2 CB’s & 18”- 24” concrete pipe Structures with 18”-24” pipes - 0 - 175’ None No problems observed Ditch flow Shallow, well maintained ditch 5.6 175’ - 200’ None See photos #1, #2 Type 2 CB’s & 24”- 30” concrete pipe Structures with 24”-30” pipes 0.26-6.2 200’ - 540’ None See Figure 7 2/26/16 Senza Lakeview Preliminary Technical Information Report CPH Project No. 0139-15-001 March 4, 2016 CP|H CONSULTANTS PHOTO #1 – LOOKING EAST AT OUTFALL OF PHOTO #2 – LOOKING WEST AT INLET TO CONVEYANCE PIPE UNDER RAILROAD EXISTING CONVEYANCE SYSTEM BUILT DURING BARBEE MILL PROJECT Site Planning Civil Engineering Project Management Land Development Consulting APPENDIX G NPDES PERMIT STATE OF WASHINGTON DEPARTMENT OF ECOLOGY PO Box 47600 • Olympia, WA 98504-7600 • 360-407-6000 711 for Washington Relay Service • Persons with a speech disability can call 877-833-6341 February 13, 2017 Levi Rowse iCap Lakeview, LLC 3535 Factoria Blvd SE Ste 500 Bellevue, WA 98006-1298 RE: Coverage under the Construction Stormwater General Permit Permit number: WAR305059 Site Name: Senza Lakeview Location: 3907 Park Ave N Renton County: King Disturbed Acres: 434 Dear Mr. Rowse: The Washington State Department of Ecology (Ecology) received your Notice of Intent for coverage under Ecology's Construction Stormwater General Permit (permit). This is your permit coverage letter. Your permit coverage is effective on February 13,2017. Please retain this permit coverage letter with your permit (enclosed), stormvitater pollution prevention plan (SWPPP), and site log book. These materials are the official record of permit coverage for your site. Please take time to read the entire permit and contact Ecology if you have any questions. Appeal Process You have a right to appeal coverage under the general permit to the Pollution Control Hearing Board (PCHB) within 30 days of the date of receipt of this letter. This appeal is limited to the general permit's applicability or non-applicability to a specific discharger. The appeal process is governed by chapter 43.21B RCW and chapter 371-08 WAC. "Date of receipt" is defined in RCW 43.21B.001(2). To appeal, you must do the following within 30 days of the date of receipt of this letter: • File your appeal and a copy of the permit cover page with the PCHB (see addresses below). Filing means actual receipt by the PCHB during regular business hours. • Serve a copy of your appeal and the permit cover page on Ecology in paper form - by mail or in person (see addresses below). E-mail is not accepted. You must also comply with other applicable requirements in chapter 43.2IB RCW and chapter 371-08 WAC. Levi Rowse February 13, 2017 Page 2 Address and Location Information: Street Addresses: Department of Ecology Attn: Appeals Processing Desk 300 Desmond Drive SE Lacey, WA 98503 Mailing Addresses: Department of Ecology Attn: Appeals Processing Desk PO Box 47608 Olympia, WA 98504-7608 Pollution Control Hearings Board (PCHB) 1111 Israel Road SW, Suite 301 Tumwater, WA 98501 Pollution Control Hearings Board PO Box 40903 Olympia, WA 98504-0903 Electronic Discharge Monitoring Reports (WQWebDMR) This permit requires that Pennittees submit monthly discharge monitoring reports (DMRs) electronically using Ecology's secure online system, WQWebDMR. To sign up for WQWebDMR go to: www.ecy.wa.gov/programs/wq/permits/paris/webdmr.html. If you have questions, contact the portal staff at (360) 407-7097 (Olympia area), or (800) 633-6193/option 3, or email WQWebPortal@ecy.wa.gov. Ecology Field Inspector Assistance If you have questions regarding stormwater management at your construction site, please contact Greg Stegman of Ecology's Northwest Regional Office in Bellevue at greg.stegman@ecy.wa.gov or (425) 649-7019. Questions or Additional Information Ecology is committed to providing assistance. Please review our web page at: www.ecy.wa.gov/programs/wq/stormwater/construction. If you have questions about the construction stormwater general permit, please contact RaChelle Stane at rcla461@ecy.wa.gov or (360) 407-6556. Sincerely, Bill Moore, P.E., Manager Program Development Services Section Water Quality Program Enclosure Site Planning Civil Engineering Project Management Land Development Consulting APPENDIX G BARBEE MILL OFFISTE BNSF RAILROAD BYPASS ANALYSIS