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HomeMy WebLinkAboutTIR_4124      FINAL  TECHNICAL INFORMATION REPORT    FOR NE 24th STREET SHORT PLAT    CITY OF RENTON IN KING COUNTY, WASHINGTON                      Prepared by:  Sheri Murata, P.E.  First Submittal:  February 12, 2020  Revised:  Aug 7, 2020, Dec 14, 2020, Feb 9, 2021  Core No.:      18265    2/9/21 DEVELOPMENT ENGINEERING bbannwarth 02/19/2021 SURFACE WATER UTILITY jfarah 02/19/2021 Core Design, Inc. NE 24th STREET SHORT PLAT i NE 24th Street Short Plat Table of Contents 1 PROJECT OVERVIEW ..................................................................................................................... 1 Figure 1-1: Vicinity Map ..................................................................................................... 2 2 CONDITIONS AND REQUIREMENTS SUMMARY ........................................................................... 8 2.1 Core Requirements ............................................................................................................... 9 2.1.1 Core Requirement #1: Discharge at the Natural Location ............................................ 9 2.1.2 Core Requirement #2: Offsite Analysis .......................................................................... 9 2.1.3 Core Requirement #3: Flow Control .............................................................................. 9 2.1.4 Core Requirement #4: Conveyance System .................................................................. 9 2.1.5 Core Requirements #5: Erosion and Sediment Control ................................................. 9 2.1.6 Core Requirement #6: Maintenance and Operations ................................................... 9 2.1.7 Core Requirement #7: Financial Guarantees and Liability ............................................ 9 2.1.8 Core Requirement #8: Water Quality ............................................................................ 9 2.1.8 Core Requirement #9: On-Site BMPs............................................................................. 9 2.2 Special Requirement #1: Other Adopted Area-Specific Requirements. ............................. 11 2.2.1 Critical Drainage Areas ................................................................................................. 11 2.2.2 Master Drainage Plan .................................................................................................. 11 2.2.3 Basin Plans ................................................................................................................... 11 2.2.4 Salmon Conservation Plans (SCPs) ............................................................................... 11 2.2.5 Stormwater Compliance Plans (SWCPs) ...................................................................... 11 2.2.6 Lake Management Plans (LMPs) .................................................................................. 11 2.2.7 Flood Hazard Reduction Plan Updates (FHRPs) ........................................................... 12 2.2.8 Shared Facility Drainage Plans (SFDPs) ........................................................................ 12 2.3 Special Requirement #2: Floodplain / Floodway Delineation ............................................. 12 2.4 Special Requirement #3: Flood Protection Facilities .......................................................... 12 2.5 Special Requirement #4: Source Controls ........................................................................... 12 2.6 Special Requirement #5: Oil Control ................................................................................... 12 2.7 Special Requirement #6: Aquifer Protection Area .............................................................. 12 3 OFFSITE ANALYSIS ....................................................................................................................... 13 Core Design, Inc. NE 24th STREET SHORT PLAT ii TASK 1 Study Area Definition and Maps ................................................................................... 13 TASK 2 Resource Review ........................................................................................................... 13 TASK 3 Field Investigation ......................................................................................................... 14 Figure 3-1: Downstream Drainage Exhibit....................................................................... 16 TASK 4 Drainage System Description and Problem Description ............................................... 17 TASK 5 Mitigation of Existing and Potential Problems .............................................................. 17 4 FLOW CONTROL AND WATER QUALITY DESIGN ........................................................................ 20 4.1 Predeveloped Site Hydrology .............................................................................................. 20 4.2 Developed Site Hydrology ................................................................................................... 21 4.3 Performance Standards....................................................................................................... 22 Figure 4-1: Existing Conditions Exhibit ............................................................................ 23 Figure 4-2: Developed Conditions Exhibit ....................................................................... 24 4.4 Flow Control System ........................................................................................................... 25 4.5 Water Quality Calculations ................................................................................................. 27 5 CONVEYANCE SYSTEM ANALYSIS AND DESIGN .......................................................................... 28 6 SPECIAL REPORTS AND STUDIES ................................................................................................. 29 7 OTHER PERMITS .......................................................................................................................... 30 8 ESC ANALYSIS AND DESIGN ........................................................................................................ 31 9 BOND QUANTITIES, FACILITY SUMMARIES, AND DECLARATION OF COVENANT ...................... 33 9.1 Bond Quantities .................................................................................................................. 33 9.2 Facility Summaries .............................................................................................................. 33 9.3 Declaration of Covenant ..................................................................................................... 33 10 OPERATIONS AND MAINTENANCE ........................................................................................... 47 Core Design, Inc. NE 24th STREET SHORT PLAT iii Appendix A – Parcel & Basin Information King County Parcel Report Flow Control Map Appendix B – Resource Review & Off-site Analysis Documentation Aquifer Protection Zone FIRM Map Coal Mine Hazard Map Erosion Hazard Map Slide Hazard Map Steep Slopes Map FEMA Flood Map Drainage Complaints Exhibit Appendix C – Flow Control Calculations MGSFlood Results Appendix D – Soil Evaluation Geotechnical Report Core Design, Inc. NE 24TH STREET SHORT PLAT Page 1 1 PROJECT OVERVIEW The project site is located at 4709 NE 24th Street, on the south side of NE 24th Street, just east of Duvall Avenue NE in the City of Renton, King County in the northeast quarter of the northwest quarter of Section 3, Township 23 North, Range 5 East, W.M. It lies in the May Creek drainage basin. The site is bordered by single family residential on the south and east, NE 24th Street to the north and Duvall Avenue to the west. The King County tax parcel ID numbers for the existing parcel is shown in Table 1 below (refer to the King County Parcel Reports included in Appendix A). Table 1: Parcel Information KC Parcel # Site Address Site Area (SF) 0323059245 4709 NE 24th Street 23,770 The total project site is 0.55 acres in size with mainly dirt and gravel surrounding the existing house. The site drains to the west at a slope ranging between 3 and 7 percent. There is minimal upstream flow from the fully vegetated backyard of 2350 Duvall Avenue NE. Proposed development of the property will include constructing two new lots, pavement widening, driveways, utilities and a stormwater flow control facility. Frontage improvements include a ROW dedication of 26.5 feet including an additional 13 feet of pavement with curb, gutter, an 8-foot planter and 5-foot sidewalk on the south side of NE 24th Street. See Figure 1-1: Vicinity Map, provided below. The project will be designed using the guidelines and requirements established in the 2017 City of Renton Surface Water Design Manual (2017 RSWDM). The project must meet the flow control duration standard matching forested site conditions and is exempt from Basic Water Quality treatment. The drainage analysis for the project was completed using MGSFlood. Core Design, Inc. NE 24TH STREET SHORT PLAT Page 2 Figure 1-1: Vicinity Map PROJECT SITE KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL TECHNICAL INFORMATION REPORT (TIR) WORKSHEET Part 1 PROJECT OWNER AND PROJECT ENGINEER Part 2 PROJECT LOCATION AND DESCRIPTION Project Owner ___________________________ Phone _________________________________ Address _______________________________ _______________________________________ Project Engineer _________________________ Company ______________________________ Phone _________________________________ Project Name _________________________ DPER Permit # ________________________ Location Township ______________ Range ________________ Section ________________ Site Address __________________________ _____________________________________ Part 3 TYPE OF PERMIT APPLICATION Part 4 OTHER REVIEWS AND PERMITS Landuse (e.g.,Subdivision / Short Subd. / UPD) Building (e.g.,M/F / Commercial / SFR) Clearing and Grading Right-of-Way Use Other _______________________ DFW HPA COE 404 DOE Dam Safety FEMA Floodplain COE Wetlands Other ________ ShorelineManagement StructuralRockery/Vault/_____ ESA Section 7 Part 5 PLAN AND REPORT INFORMATION Technical Information Report Site Improvement Plan (Engr. Plans) Type of Drainage Review (check one): Date (include revision dates): Date of Final: Full Targeted Simplified Large Project Directed ____________________________________ __________________ Plan Type (check one): Date (include revision dates): Date of Final: Full Modified Simplified ____________________________________ __________________ Part 6 SWDM ADJUSTMENT APPROVALS Type (circle one): Standard / Experimental / Blanket Description: (include conditions in TIR Section 2) ____________________________________________________________________________________ ____________________________________________________________________________________ ____________________________________________________________________________________ Approved Adjustment No. ______________________ Date of Approval: ______________________ 2016 Surface Water Design Manual 4/24/2016 1 KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL TECHNICAL INFORMATION REPORT (TIR) WORKSHEET Part 7 MONITORING REQUIREMENTS Monitoring Required: Yes / No Start Date: _______________________ Completion Date: _______________________ Describe: _________________________________ _________________________________________ _________________________________________ Re: KCSWDM Adjustment No. ________________ Part 8 SITE COMMUNITY AND DRAINAGE BASIN Community Plan : ____________________________________________________________________ Special District Overlays: ______________________________________________________________ Drainage Basin: _____________________________________________________________________ Stormwater Requirements: ____________________________________________________________ Part 9 ONSITE AND ADJACENT SENSITIVE AREAS  River/Stream ________________________  Lake ______________________________  Wetlands ____________________________  Closed Depression ____________________  Floodplain ___________________________  Other _______________________________ _______________________________  Steep Slope __________________________  Erosion Hazard _______________________  Landslide Hazard ______________________  Coal Mine Hazard ______________________  Seismic Hazard _______________________  Habitat Protection ______________________  _____________________________________ Part 10 SOILS Soil Type _________________ _________________ _________________ _________________ Slopes _________________ _________________ _________________ _________________ Erosion Potential _________________ _________________ _________________ _________________  High Groundwater Table (within 5 feet)  Other ________________________________  Sole Source Aquifer  Seeps/Springs  Additional Sheets Attached 2016 Surface Water Design Manual 4/24/2016 2 KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL TECHNICAL INFORMATION REPORT (TIR) WORKSHEET Part 11 DRAINAGE DESIGN LIMITATIONS REFERENCE  Core 2 – Offsite Analysis_________________  Sensitive/Critical Areas__________________  SEPA________________________________  LID Infeasibility________________________  Other________________________________  _____________________________________ LIMITATION / SITE CONSTRAINT _______________________________________ _______________________________________ _______________________________________ _______________________________________ _______________________________________ _______________________________________  Additional Sheets Attached Part 12 TIR SUMMARY SHEET (provide one TIR Summary Sheet per Threshold Discharge Area) Threshold Discharge Area: (name or description) Core Requirements (all 8 apply): Discharge at Natural Location Number of Natural Discharge Locations: Offsite Analysis Level: 1 / 2 / 3 dated:__________________ Flow Control (include facility summary sheet) Level: 1 / 2 / 3 or Exemption Number ____________ Flow Control BMPs _______________________________ Conveyance System Spill containment located at: _________________________ Erosion and Sediment Control / Construction Stormwater Pollution Prevention CSWPP/CESCL/ESC Site Supervisor: _____________________ Contact Phone: _________________________ After Hours Phone: _________________________ Maintenance and Operation Responsibility (circle one): Private / Public If Private, Maintenance Log Required: Yes / No Financial Guarantees and Liability Provided: Yes / No Water Quality (include facility summary sheet) Type (circle one): Basic / Sens. Lake / Enhanced Basic / Bog or Exemption No. ______________________ Landscape Management Plan: Yes / No Special Requirements (as applicable): Area Specific Drainage Requirements Type: CDA / SDO / MDP / BP / LMP / Shared Fac. / None Name: ________________________ Floodplain/Floodway Delineation Type (circle one): Major / Minor / Exemption / None 100-year Base Flood Elevation (or range): ______________ Datum: Flood Protection Facilities Describe: 2016 Surface Water Design Manual 4/24/2016 3 KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL TECHNICAL INFORMATION REPORT (TIR) WORKSHEET Part 12 TIR SUMMARY SHEET (provide one TIR Summary Sheet per Threshold Discharge Area) Source Control (commercial / industrial land use) Describe land use: Describe any structural controls: Oil Control High-use Site: Yes / No Treatment BMP: ________________________________ Maintenance Agreement: Yes / No with whom? ____________________________________ Other Drainage Structures Describe: Part 13 EROSION AND SEDIMENT CONTROL REQUIREMENTS MINIMUM ESC REQUIREMENTS DURING CONSTRUCTION  Clearing Limits  Cover Measures  Perimeter Protection  Traffic Area Stabilization  Sediment Retention  Surface Water Collection  Dewatering Control  Dust Control  Flow Control  Protection of Flow Control BMP Facilities (existing and proposed)  Maintain BMPs / Manage Project MINIMUM ESC REQUIREMENTS AFTER CONSTRUCTION  Stabilize exposed surfaces  Remove and restore Temporary ESC Facilities  Clean and remove all silt and debris, ensure operation of Permanent Facilities, restore operation of Flow Control BMP Facilities as necessary  Flag limits of SAO and open space preservation areas  Other ______________________ Part 14 STORMWATER FACILITY DESCRIPTIONS (Note: Include Facility Summary and Sketch) Flow Control Type/Description Water Quality Type/Description  Detention  Infiltration  Regional Facility  Shared Facility  Flow Control BMPs  Other ________________ ________________ ________________ ________________ ________________ ________________  Vegetated Flowpath  Wetpool  Filtration  Oil Control  Spill Control  Flow Control BMPs  Other ________________ ________________ ________________ ________________ ________________ ________________ ________________ 2016 Surface Water Design Manual 4/24/2016 4 KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL TECHNICAL INFORMATION REPORT (TIR) WORKSHEET Part 15 EASEMENTS/TRACTS Part 16 STRUCTURAL ANALYSIS Drainage Easement Covenant Native Growth Protection Covenant Tract Other ___________________________ Cast in Place Vault Retaining Wall Rockery > 4’ High Structural on Steep Slope Other ______________________________ Part 17 SIGNATURE OF PROFESSIONAL ENGINEER I, or a civil engineer under my supervision, have visited the site. Actual site conditions as observed were incorporated into this worksheet and the attached Technical Information Report. To the best of my knowledge the information provided here is accurate. Signed/Date 2016 Surface Water Design Manual 4/24/2016 5 12/14/20 Core Design, Inc. NE 24TH STREET SHORT PLAT Page 8 2 CONDITIONS AND REQUIREMENTS SUMMARY Core Design, Inc. NE 24TH STREET SHORT PLAT Page 9 The proposed project is classified as requiring “Full Drainage Review” per the 2017 RSWDM. Therefore, all nine core requirements and six special requirements will be addressed per Section 1.1 of the 2017 RSWDM). 2.1 Core Requirements 2.1.1 Core Requirement #1: Discharge at the Natural Location The project will maintain the natural discharge location on the west side of the parcel to the storm drain system in Duvall Avenue NE. 2.1.2 Core Requirement #2: Offsite Analysis This core requirement is addressed in Section 3 of this report. 2.1.3 Core Requirement #3: Flow Control The detention vault is designed to meet the flow control duration standard matching forested site conditions. This requires that the developed condition discharge durations match the predeveloped (forested) condition durations from 50% of the 2-year to the 50-year storm events and that the developed 2-year and 10-year peak discharge rates do not exceed the predeveloped (forested) 2-year and 10-year peak discharge rates, respectively. 2.1.4 Core Requirement #4: Conveyance System Conveyance Calculations will be provided in Section 5 to show that the proposed conveyance system provides sufficient capacity for the 25-year storm as calculated by the Rational Method. 2.1.5 Core Requirements #5: Erosion and Sediment Control Erosion and sediment control will be provided through catch basin protection, interceptor swales, rock check dams, silt fencing and a construction access entrance. 2.1.6 Core Requirement #6: Maintenance and Operations The City of Renton will be responsible for the maintenance and operations of the stormwater facility located in the right of way. An Operations and Maintenance Manual will be provided in Section 10. 2.1.7 Core Requirement #7: Financial Guarantees and Liability A bond quantities worksheet has been provided in Section 9. 2.1.8 Core Requirement #8: Water Quality The project does not add more than 5,000 square feet of new plus replaced pollution generating impervious surface. 2.1.8 Core Requirement #9: On-Site BMPs The project site is larger than 22,000 square feet; thus, the site falls under Large Lot BMP Requirements. The following list must be evaluated in order to meet the lot BMP requirement. All referenced sections are pre 2017 RSWDM. Core Design, Inc. NE 24TH STREET SHORT PLAT Page 10 1. The feasibility and applicability of full dispersion as detailed in Appendix C, Section C.2.1 must be evaluated for all target impervious surfaces. • Response: Full dispersion is not applicable due to site constrains. 2. Where full dispersion of target imperious roof areas is not feasible or applicable, will cause flooding or erosion impacts, the feasibility and applicability of full infiltration of roof runoff must be evaluated in accordance with Appendix C, Section C.2.2, or Section 5.2, whichever is applicable based on the type of project. • Response: Per the Stormwater Feasibility Evaluation completed by Cobalt Geosciences on March 28, 2017, TP-1 taken on the south half of lot 1 should be considered Medium Sand and should have a length of 30 feet for every 1,000 square feet of impervious surface area. Infiltration did not appear feasible on the east lot. Therefore, infiltration trenches are only proposed on lot 1. 3. All target impervious surfaces not mitigated by Requirements 1 and 2 above, must be mitigated to the maximum extent feasible using one or more BMPs from the following list. • Full infiltration per Section C2.2, or per Section 5.2, whichever is applicable Response: Full infiltration trenches are only proposed on lot 1 where there are infiltrative soils. • Limited infiltration per Appendix C, Section C.2.3, Response: Limited infiltration trenches have been considered infeasible since there are full infiltration trenches on lot 1 and infiltration is infeasible on lot 2 • Bioretention per Appendix C, Section C.2.6. Response: Bioretention has been considered infeasible since there are full infiltration trenches on lot 1 and infiltration is infeasible on lot 2 • Permeable Pavement per Appendix C, Section C.2.7. Response: Permeable Pavement has been considered infeasible since the infiltrative soils were only found on the south side of Lot 1. 4. All target impervious surfaces not mitigated by Requirements 1,2 and 3 above, must be mitigated to the maximum extent feasible using the Basic Dispersion BMP. • Response: Not applicable. Full infiltration of roof runoff BMP will be implemented for all of Lot 2 and a portion of Lot 1. The remaining roof area of the existing house on lot 2 will discharge to the vault since a 25-foot flow path cannot be provided while maintaining the required setbacks. Core Design, Inc. NE 24TH STREET SHORT PLAT Page 11 5. BMPs must be implemented, at minimum, for impervious area amounts defined as follows. For projects that will result in an impervious surface coverage on the buildable portion of the site/lot of less than 45%, flow control BMPs must be applied to 50% of target impervious surfaces. For projects that will result in an impervious surface coverage 45-65% on the buildable portion of the site/lot, flow control BMPs must be applied to 50% of target impervious surfaces reduced by 1.5% for each 1% of impervious surface coverage above 45% (e.g. impervious coverage of 55% results in a requirement of FCBMPs applied to 35% of target impervious surfaces). For projects that will result in an impervious surface coverage greater than 65% on the buildable portion of the site/lot, flow control BMPs must be applied to 20% of the target impervious surfaces or to an impervious area equal to at least 10% of the site/lot, whichever is less. 2.2 Special Requirement #1: Other Adopted Area-Specific Requirements. • Response: The minimum BMP area has been met with the full infiltration trenches proposed. 6. The soil moisture holding capacity of new pervious surfaces must be protected in accordance with KCC 16.82.100 (F) and (G). • Response: The project will implement amended soil over all disturbed areas. 7. Any proposed connection of roof downspouts to the drainage system must be via a perforated pipe connection as detailed in Appendix C, Section C.2.11. • Response: A perforated pipe connection will be provided with the building permit if the design requirements can be met. 2.2 Special Requirement #1: Other Adopted Area-Specific Requirements. 2.2.1 Critical Drainage Areas Per the City’s Aquifer Protection Zone map, the project is not in an aquifer protection zone. 2.2.2 Master Drainage Plan Not applicable. 2.2.3 Basin Plans There are no basin plans for this project. 2.2.4 Salmon Conservation Plans (SCPs) There are no salmon conservation plan for this project. 2.2.5 Stormwater Compliance Plans (SWCPs) Not applicable. 2.2.6 Lake Management Plans (LMPs) Not applicable. Core Design, Inc. NE 24TH STREET SHORT PLAT Page 12 2.2.7 Flood Hazard Reduction Plan Updates (FHRPs) This project is not within a floodplain (see FEMA map included in Appendix B) and is not within an area with an applicable Flood Hazard Reduction Plan. Therefore, additional requirements from a Flood Hazard Reduction Plan do not apply. 2.2.8 Shared Facility Drainage Plans (SFDPs) Not applicable. 2.3 Special Requirement #2: Floodplain / Floodway Delineation This project is not located within the 100-year floodplain (see FEMA Map included in Appendix B). 2.4 Special Requirement #3: Flood Protection Facilities As this project is not located within a 100-year floodplain there are no levees, revetments or berms within the project. 2.5 Special Requirement #4: Source Controls These requirements are not applicable as the project is not a commercial, industrial or multi- family development. 2.6 Special Requirement #5: Oil Control This requirement does not apply because the project is not a commercial or industrial development nor is it expected to have more than 15,000 vehicles per day. 2.7 Special Requirement #6: Aquifer Protection Area The project site is not located within a protected aquifer area; thus, this special requirement is not applicable. Core Design, Inc. NE 24TH STREET SHORT PLAT Page 13 3 OFFSITE ANALYSIS TASK 1 Study Area Definition and Maps The proposed project contains parcel number 0323059245. A map of the downstream can be found in Figure 3-1 Downstream Drainage Exhibit. TASK 2 Resource Review Basin Reconnaissance Summary Reports: No Basin Reconnaissance Summary Reports appear to be available for the area that is within one mile of this project site. FEMA Maps: Per the City’s Effective FEMA Flood Insurance Rate Map, the project site is not in the 100-year floodplain. The FEMA Map is included in Appendix B. Sensitive Areas Folio: Per the City of Renton Sensitive Areas Maps, this project not located in any sensitive areas. Soils The Geotechnical Report was completed by Cobalt Geosciences on March 28, 2017. Under the topsoil of Test Pit 1 (TP-1) there was “approximately 2 feet of loose to medium dense, silty-fine to medium grained sand with gravel (fill). This layer was underlain by approximately 3.5 feet of medium dense, fine to coarse grained gravel with sand. Under the topsoil of Test Pit 2 (TP-2) there was “approximately 3.5 feet of loose, silty-sand to sandy silt. This layer was underlain by medium stiff to stiff, silt with fine grained sand. Downstream Drainage Complaints Drainage complaints were researched within the study area. King County lists two complaints (1982- 0030 and 1998-0427) within a quarter mile of the downstream discharge point. The first complaint was regarding cleaning out a road culvert and was closed on 12/29/82. The second complaint was regarding a potential downstream impact in Newcastle and closed on 8/5/98. See the Drainage Complaint Exhibit in Appendix B. Restrictive Well Covenant There is no existing well onsite. Core Design, Inc. NE 24TH STREET SHORT PLAT Page 14 TASK 3 Field Investigation Upstream Tributary Area It is estimated that approximately 0.56 ac of offsite area consisting of about 50% forest and 50% pasture from the east drains toward the project. The City’s GIS records indicate that there is an infiltration trench (located in yellow below) on the east side of the property, however it has been confirmed that no such system exists. The runoff generated from the offsite area is shown below: Core Design, Inc. NE 24TH STREET SHORT PLAT Page 15 In the 100-year storm event it is estimated that 0.12 cfs will be generated. This runoff will be captured by the footing drains of lot 2 so no additional storm water infrastructure is proposed. In the event that the property to the east is developed, that project will be responsible for providing the required mitigation. Downstream Analysis The site drains west to an existing catch basin located in a low spot at the back of sidewalk on Duvall Avenue NE just south of NE 24th Street. A 12-inch storm pipe heads west to a 24-inch storm drain system in the center of Duvall Avenue NE which continues north for 400 feet before daylighting to the northeast through an undeveloped parcel in a 12-inch pipe. From this point the drainage continues through private property via overland flow about 1,000 feet before discharging into May Creek. 4,514 376 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. None 11/12/2019 Legend 2560 128 THIS MAP IS NOT TO BE USED FOR NAVIGATION Feet Notes 256 WGS_1984_Web_Mercator_Auxiliary_Sphere Information Technology - GIS RentonMapSupport@Rentonwa.gov Streets Points of Interest Parks Waterbodies Extent2010 Project Site May Creek Core Design, Inc. NE 24th STREET SHORT PLAT Page 17 TASK 4 Drainage System Description and Problem Description See the Drainage Complaints Map and drainage complaint request in Appendix B. TASK 5 Mitigation of Existing and Potential Problems Downstream Drainage Problems Requiring Special Attention Type 1 – Conveyance System Nuisance Problems There are no known, reported or observed current downstream conveyance nuisance problems. Type 2 – Severe Erosion Problems There are no known, reported or observed current downstream severe erosion problems. Type 3-Severe Flooding Problems There are no known, reported or observed current downstream severe flooding problems. Downstream Water Quality Problems Requiring Special Attention Type 1 – Bacteria Problems There are no known or reported downstream bacteria problems. Type 2 – Dissolved Oxygen (DO) Problems There are no known or reported downstream dissolved oxygen problems. Type 3 – Temperature Problems May Creek is a Category 5 for Temperature. See listing information on the next page. Type 4 – Metals Problems There are no known or reported downstream metals problems. Type 5 – Phosphorous Problems There are no known or reported downstream phosphorous problems. Type 6 – Turbidity Problems There are no known or reported downstream turbidity problems. Core Design, Inc. NE 24th STREET SHORT PLAT Page 18 Core Design, Inc. NE 24th STREET SHORT PLAT Page 19 Type 7 – High pH Problems There are no known or reported downstream high pH problems. Bioassessment May Creek is a Category 2 for bioassessment. Drainage Adjustments There are no proposed drainage adjustments. Core Design, Inc. NE 24th STREET SHORT PLAT Page 20 4 FLOW CONTROL AND WATER QUALITY DESIGN 4.1 Predeveloped Site Hydrology The disturbed area is approximately 0.57 acres with 0.04 acres of offsite area for a total project area of 0.61 acres. The existing site has one residence with several sheds and gravel occupying the majority of the front yard. There are two trees on the west side of the property with an existing rockery running in the north-south direction close to where the proposed lot line will be. The site drains to the west at slope ranging between 3 and 7 percent. There is offsite pervious area to the east which has been discussed in Section 3 and is not anticipated to impact the project. It appears that the northern half parcel east of the site contribute runoff to the project area. Historic site conditions are assumed for all existing onsite areas per Section 1.2.3.1 of the 2017 RSWDM (page 1-43) and are modeled as Till Forest and Outwash-Forest, except for the existing pavement on NE 24th Street upstream to the east of the site that will drain to the proposed detention facility. The area where the proposed infiltration trench is proposed has been modeled as outwash forest in the predeveloped condition since the test pit indicates that the area is classified as a medium sand. The test pit near the existing house did not have infiltrative soils, so the remaining area was considered till forest. The predeveloped areas are summarized in Table 4-1 below and Figure 4-1 Predeveloped Conditions. Table 4-1 Predeveloped Conditions Areas GROUND COVER AREA (acres) Till-Forest 0.50 Outwash-Forest 0.05 Upstream Impervious 0.02 TOTAL 0.57 Predeveloped Peak Flows Predeveloped Scenario from MGSFlood and peak flow rates: Core Design, Inc. NE 24th STREET SHORT PLAT Page 21 4.2 Developed Site Hydrology In the developed condition, the site will continue to drain to the west. The south half of NE 24th Street, the driveways and a portion of the roof of Lot 1 will discharge to the detention vault. The roof of Lot 2 and the remainder of the roof for Lot 1 will discharge to the infiltration trenches on Lot 1. The developed condition areas are summarized in Table 4-2 below and Figure 4-2 Developed Conditions Map. It has been determined (in Section 4.4) that 5,166 square feet (or 2,583 square feet from each lot) of roof area can drain to the infiltration trench. Since the project is providing full infiltration the area draining to the trench been modeled as outwash forest and considered to no have no effective impervious area. The outwash grass area on lot 1 is the area that was modeled as outwash forest in the predeveloped condition. There is upstream area to the east of the project on NE 24th Street that is unable bypass the project. Approximately 2,821 square feet of upstream impervious area will drain into the vault (see snip below) and in lieu 2,180 square feet of developed impervious area will discharge to the existing storm undetained. Therefore, since the project is detaining more upstream area than it is releasing in the developed condition, 641 square feet (2,821 – 2,180) has been modeled as impervious in the predeveloped condition. Core Design, Inc. NE 24th STREET SHORT PLAT Page 22 Table 4-2 Developed Area Total Impervious Effective Impervious Till-Grass Outwash- Grass Outwash Forest Lot 1 10,269 4,000 1,417 4,166 2,091 2,583 Lot 2 9,271 4,000 1,417 5,271 0 2,583 ROW 2,296 1,800 1,800 496 0 0 Upstream 2,821 2,821 2,821 TOTAL (sf) 24,657 12,621 7,454 9,945 2,091 5,167 TOTAL (ac) 0.57 0.29 0.17 0.23 0.05 0.12 Developed Peak Flows The Developed scenario from MGSFlood is shown below: 4.3 Performance Standards Flow Control: The Flow Control Duration Standard Matching Forested Site Conditions requires maintaining the durations of high flows at their pre-development (forested site conditions) levels for all flows greater than one-half of the 2-year peak flow through the 50-year peak flow. The pre-development peak flow rates for the 2-year and 10-year runoff events must also be maintained under this requirement. Conveyance Capacity: The proposed conveyance system has been designed with sufficient capacity to convey and contain the 25-year peak flow as determined by the Rational Method. It will also be verified that the 100-year peak flow will not create or aggravate a severe flooding or erosion problem per Section 1.2.2. Water Quality: Basic Water Quality Menu This project will add less than 5,000 square feet of pollution generating hard surface, so no water quality treatment is required. IN COMPLIANCE WITH CITY OF RENTON STANDARDS IN COMPLIANCE WITH CITY OF RENTON STANDARDS Core Design, Inc. NE 24th STREET SHORT PLAT Page 25 4.4 Flow Control System Calculation of Lot Impervious Area The impervious area per lot applied to the developed basin time series file was determined using the criteria in the 2017 RSWDM page 3-27. The proposed development is urban residential. The site is zoned R-4 (see parcel information in Appendix A). The minimum impervious area per lot per the 2017 RSWDM (page 3-27) would either be 4,000 square feet or the maximum impervious area based on zoning, whichever is less. The maximum impervious surface allowed in the R-4, zone in the City of Renton, is 50%. Large Lot BMP Requirements Additional BMPs beyond the infiltration trenches will be determined with the building permit. The length criteria for infiltration is trench is 30 LF for every 1,000 square feet of impervious surface. It was determined that 155-feet of infiltration trench can be constructed on the south side of lot 1, therefore 5,166 square feet of roof area can drain to the trench. (155’/30’) x 1,000 sf of impervious = 5,166 square feet A depth of 3 feet will be provided to the bottom of the trench with 2 feet width. Flow Control A 63’-7”x12’ detention vault will be located in the right of way. The flow control facility summary is located below, and the full report has been included in Appendix C. Link Name: Det Vault Link Type: Structure Downstream Link: None Prismatic Pond Option Used Pond Floor Elevation (ft) : 415.75 Riser Crest Elevation (ft) : 421.00 Max Pond Elevation (ft) : 422.00 Storage Depth (ft) : 5.25 Pond Bottom Length (ft) : 63.6 Pond Bottom Width (ft) : 12.0 Pond Side Slopes (ft/ft) : L1= 0.00 L2= 0.00 W1= 0.00 W2= 0.00 Bottom Area (sq.-ft) : 763. Area at Riser Crest El (sq.-ft) : 763. (acres) : 0.018 Volume at Riser Crest (cu-ft) : 4,006. (ac-ft) : 0.092 Area at Max Elevation (sq.-ft) : 763. (acres) : 0.018 Vol at Max Elevation (cu-ft) : 4,769. (ac-ft) : 0.109     Core Design, Inc. NE 24th STREET SHORT PLAT Page 26  Massmann Infiltration Option Used Hydraulic Conductivity (in/hr.) : 0.00 Massmann Regression Used to Estimate Hydraulic Gradient Depth to Water Table (ft) : 100.00 Bio-Fouling Potential : Low Maintenance : Average or Better Riser Geometry Riser Structure Type : Circular Riser Diameter (in) : 8.00 Common Length (ft) : 0.000 Riser Crest Elevation : 421.00 ft Hydraulic Structure Geometry Number of Devices: 3 ---Device Number 1 --- Device Type : Circular Orifice Control Elevation (ft) : 415.75 Diameter (in) : 0.50 Orientation : Horizontal Elbow : No ---Device Number 2 --- Device Type : Circular Orifice Control Elevation (ft) : 418.50 Diameter (in) : 0.75 Orientation : Horizontal Elbow : Yes   The proposed detention system includes a two‐orifice control structure with a notch weir. The first  orifice is 1/2 inches in diameter and is at the bottom of the riser. The second orifice is at elevation 418.5  and is 3/4 inches in diameter. The 100‐year water surface elevation is 420.15    ********** Link: Det Vault ********** Link WSEL Stats WSEL Frequency Data(ft) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs.) WSEL Peak (ft) ====================================== 1.05-Year 416.905 1.11-Year 417.047 1.25-Year 417.303 2.00-Year 417.930 3.33-Year 418.378 5-Year 418.696 10-Year 419.124 25-Year 419.788 50-Year 420.034 Core Design, Inc. NE 24th STREET SHORT PLAT Page 27 100-Year 420.153 The flow duration plot below indicates that the vault passes the flow control performance criteria with no positive excursions. The vault will discharge to an existing catchbasin at the back of sidewalk on Duvall Avenue. 4.5 Water Quality Calculations The project is adding approximately 4,391 square feet of pollution generating impervious area (PGIS) which is less than 5,000 square feet so water quality treatment is not required. Table 4-3 PGIS Area GROUND COVER AREA (sf) NE 24th Street 2,773 Driveway Approaches 336 Driveways (estimated) 1,200 TOTAL 4,391 Core Design, Inc. NE 24th STREET SHORT PLAT Page 28 5 CONVEYANCE SYSTEM ANALYSIS AND DESIGN A paved area of approximately 6,345 square feet drains into the catch basin 1 in the frontage upstream of vault. Stormwater would flow into the vault through a 12” pipe. Using Rational Method, Section 3.2.1 of Renton Stormwater Design Manual, an overall flow of 0.429 cfs would drain into the vault through this pipe. Q = 9 cfs ( 9 cfs >> 0.429 cfs) Therefore, the proposed pipes will convey the 100- year peak flows. Core Design, Inc. NE 24th STREET SHORT PLAT Page 29 6 SPECIAL REPORTS AND STUDIES  Geotechnical Report Cobalt Geosciences P.O. Box 82243 Kenmore, WA 98028 Prepared by: Phil Haberman, P.G.,P.E.G. Dated: March 28, 2017 Revised: April 25, 2018  Arborist Report (provided under separate cover) Varley Landscape 12743 NE 170th Lane Woodinville, WA 98072 Prepared by: Jeff Varley Dated: May 6, 2018 Core Design, Inc. NE 24th STREET SHORT PLAT Page 30 7 OTHER PERMITS  Utilities Permit  Building Permits  ROW Use Permit Core Design, Inc. NE 24th STREET SHORT PLAT Page 31 8 ESC ANALYSIS AND DESIGN ESC Plan Analysis and Design (Part A) 1. The site will utilize Appendix D of the 2017 RSWDM for the erosion and sedimentation control design to reduce the discharge of sediment-laden runoff from the site. Clearing limits will be established prior to any earthwork on the project site. Perimeter protection will be provided by silt fencing along the entire perimeter of the site to limit the downstream transport of sediment to the neighboring properties. Dust control, if required, will be provided by a water truck. A Certified Erosion and Sediment Control Lead inspector will be present onsite during earthwork activities. The inspector shall determine frequency of watering of the project site and will authorize and direct any additional erosion and sediment control measures as needed during all construction activities. The plan will be comprised of temporary measures (stabilized construction entrance, silt fence, and inlet protection). 2. Due to the size of the project, no sediment control facilities like a sediment trap are proposed. The existing house will remain so there will be minimum clearing and grading. 3. The area where the proposed infiltration trenches will be protected again compaction and additional sediment with silt fencing. 4. There are no erosion and sediment control recommendations in any of the infiltration feasibility or arborist report. 5. The project is proposing to use the existing gravel driveway as a construction entrance. SWPPS Plan Design (Part B) The following pollution control measures shall be implemented as applicable using activity specific BMPs detailed in Section D.2.2 (and Section D.2.1 as applicable) of Appendix D and the King County Stormwater Pollution Prevention Manual (SPPM). The receiving water for this project is May Creek. 1. All pollutants, including waste materials, that occur onsite shall be handled and disposed of in a manner that does not cause contamination of stormwater 2. Chemicals, liquid products, petroleum products, and non-inert wastes are not anticipated on site. 3. Maintenance and repair of heavy equipment and vehicles involving oil changes, hydraulic system drain down, solvent and de-greasing cleaning operations, fuel tank drain down and removal, and Core Design, Inc. NE 24th STREET SHORT PLAT Page 32 other activities which may result in discharge or spillage of pollutants to the ground or into stormwater runoff are not anticipated on site. 4. Application of agricultural chemicals, including fertilizers and pesticides, shall be conducted in a manner and at application rates that will not result in loss of chemical to stormwater runoff. Manufacturers' recommendations for application rates and procedures shall be followed. 5. Stormwater discharges shall not cause or contribute to a violation of the water quality standard for pH in the receiving water. Measures shall be used to prevent or treat contamination of stormwater runoff by pH modifying sources. These sources include, but are not limited to: a. bulk cement b. cement kiln dust, fly ash c. new concrete washing and curing waters d. waste streams generated from concrete grinding and sawing e. exposed aggregate processes, and concrete pumping and mixer washout 6. For full compliance with KCC 9.12 Water Quality, the project may need to include measures for the permanent structures and features constructed under other permits. See the SPPM for Activity Sheets describing issues and measures to address them. Common issues include: a. Containment area planning for storage of liquid materials in stationary or portable tanks, storage of solid waste and food wastes including cooking grease, are not anticipated for this site. b. Permanent canopy and paving requirements for permanent outdoor vehicle parking, maintenance and storage areas are not anticipated for this site.     Core Design, Inc. NE 24th STREET SHORT PLAT Page 33  9 BOND QUANTITIES, FACILITY SUMMARIES, AND DECLARATION OF COVENANT 9.1 Bond Quantities A Site Improvement Bond Quantity Worksheet is provided at the end of this section.  9.2 Facility Summaries A Facility Summary Sheet is provided at the end of this section.  9.3 Declaration of Covenant A Declaration of Covenant will be submitted with the single family building permit for lot 1.          Planning Division |1055 South Grady Way – 6th Floor | Renton, WA 98057 (425) 430‐7200Date Prepared: Name:PE Registration No:Firm Name:Firm Address:Phone No.Email Address:Project Name: Project Owner:CED Plan # (LUA):Phone:CED Permit # (U):Address: Site Address:Street Intersection:Addt'l Project Owner:Parcel #(s):Phone:Address: Clearing and grading greater than or equal to 5,000 board feet of timber? Yes/No:NOWater Service Provided by:If Yes, Provide Forest Practice Permit #:Sewer Service Provided by: Abbreviated Legal Description:SE1/4, NW1/4, SEC. 3, TWP. 23 N., RGE. 5 E., W.M.4709 NE 24th St., Renton, WA 98059PO Box 6127,########206.714.670712/18/2020Prepared by:FOR APPROVALProject Phase 1shm@coredesigninc.comSheri Murata41846Core Design Inc.12100 NE 195th St, Suite #300, Bothell, WA 98011425.885.7877SITE IMPROVEMENT BOND QUANTITY WORKSHEETPROJECT INFORMATIONCITY OF RENTONCITY OF RENTON1 Select the current project status/phase from the following options:              For Approval ‐ Preliminary Data Enclosed, pending approval from the City;              For Construction ‐ Estimated Data Enclosed, Plans have been approved for contruction by the City;              Project Closeout ‐ Final Costs and Quantities Enclosed for Project Close‐out SubmittalEngineer Stamp Required (all cost estimates must have original wet stamp and signature)Clearing and GradingUtility ProvidersN/AProject Location and DescriptionProject Owner InformationNE 24th STREET SHORT PLATBellevue, WA 980080323059245Tuscany Construction19‐000062Page 1 of 13Ref 8‐H Bond Quantity WorksheetSECTION I PROJECT INFORMATIONUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 12/18/2020 CED Permit #:########UnitReference #PriceUnitQuantity CostBackfill & compaction‐embankmentESC‐16.50$                                            CY6184,017.00Check dams, 4" minus rockESC‐2SWDM 5.4.6.380.00$                                          Each Catch Basin ProtectionESC‐335.50$                                          Each3106.50Crushed surfacing 1 1/4" minusESC‐4WSDOT 9‐03.9(3)95.00$                                          CY DitchingESC‐59.00$                                            CY Excavation‐bulkESC‐62.00$                                            CY209418.00Fence, siltESC‐7SWDM 5.4.3.11.50$                                            LF389583.50Fence, Temporary (NGPE)ESC‐81.50$                                            LF Geotextile FabricESC‐92.50$                                            SY Hay Bale Silt TrapESC‐100.50$                                            Each HydroseedingESC‐11SWDM 5.4.2.40.80$                                            SY Interceptor Swale / DikeESC‐121.00$                                            LF Jute MeshESC‐13SWDM 5.4.2.23.50$                                            SY Level SpreaderESC‐141.75$                                            LF Mulch, by hand, straw, 3" deepESC‐15SWDM 5.4.2.12.50$                                            SY Mulch, by machine, straw, 2" deepESC‐16SWDM 5.4.2.12.00$                                            SY Piping, temporary, CPP, 6"ESC‐1712.00$                                          LF Piping, temporary, CPP, 8"ESC‐1814.00$                                          LF Piping, temporary, CPP, 12"ESC‐1918.00$                                          LF Plastic covering, 6mm thick, sandbaggedESC‐20SWDM 5.4.2.34.00$                                            SY Rip Rap, machine placed; slopesESC‐21WSDOT 9‐13.1(2)45.00$                                          CY Rock Construction Entrance, 50'x15'x1'ESC‐22SWDM 5.4.4.11,800.00$                                    Each Rock Construction Entrance, 100'x15'x1'ESC‐23SWDM 5.4.4.13,200.00$                                    Each Sediment pond riser assemblyESC‐24SWDM 5.4.5.22,200.00$                                    Each Sediment trap, 5'  high berm ESC‐25SWDM 5.4.5.119.00$                                          LF Sed. trap, 5' high, riprapped spillway berm section ESC‐26SWDM 5.4.5.170.00$                                          LF Seeding, by handESC‐27SWDM 5.4.2.41.00$                                            SY Sodding, 1" deep, level groundESC‐28SWDM 5.4.2.58.00$                                            SY Sodding, 1" deep, sloped groundESC‐29SWDM 5.4.2.510.00$                                          SY TESC SupervisorESC‐30110.00$                                       HR4440.00Water truck, dust controlESC‐31SWDM 5.4.7140.00$                                       HR UnitReference #PriceUnitQuantity Cost8.00$                                            LF106848.00  EROSION/SEDIMENT SUBTOTAL:6,413.00SALES TAX @ 10%641.30EROSION/SEDIMENT TOTAL:7,054.30(A)SITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR EROSION & SEDIMENT CONTROLDescriptionNo.(A)Tree Protection FenceWRITE‐IN‐ITEMS Page 2 of 13Ref 8‐H Bond Quantity WorksheetSECTION II.a EROSION_CONTROLUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 12/18/2020 CED Permit #:########ExistingFuture PublicPrivateRight‐of‐WayImprovementsImprovements(D) (E)DescriptionNo. Unit Price Unit Quant. Cost Quant. Cost Quant. Cost Quant. CostGENERAL ITEMS Backfill & Compaction‐ embankmentGI‐16.00$              CYBackfill & Compaction‐ trenchGI‐29.00$              CYClear/Remove Brush, by hand (SY)GI‐31.00$              SYBollards ‐ fixedGI‐4 240.74$          EachBollards ‐ removableGI‐5 452.34$          EachClearing/Grubbing/Tree RemovalGI‐6 10,000.00$    AcreExcavation ‐ bulkGI‐72.00$              CYExcavation ‐ TrenchGI‐85.00$              CYFencing, cedar, 6' highGI‐9 20.00$            LFFencing, chain link, 4'GI‐10 38.31$            LFFencing, chain link, vinyl coated,  6' highGI‐11 20.00$            LFFencing, chain link, gate, vinyl coated,  20' GI‐12 1,400.00$      EachFill & compact ‐ common barrowGI‐13 25.00$            CYFill & compact ‐ gravel baseGI‐14 27.00$            CY3088,316.00Fill & compact ‐ screened topsoilGI‐15 39.00$            CYGabion, 12" deep, stone filled mesh GI‐16 65.00$            SYGabion, 18" deep, stone filled mesh GI‐17 90.00$            SYGabion, 36" deep, stone filled meshGI‐18 150.00$          SYGrading, fine, by handGI‐19 2.50$              SYGrading, fine, with graderGI‐20 2.00$              SY308616.00Monuments, 3' LongGI‐21 250.00$          EachSensitive Areas SignGI‐22 7.00$              EachSodding, 1" deep, sloped groundGI‐23 8.00$              SYSurveying, line & gradeGI‐24 850.00$          Day0.5425.000.5425.00Surveying, lot location/linesGI‐25 1,800.00$      Acre0.55990.00Topsoil Type A (imported)GI‐26 28.50$            CY1052,992.50Traffic control crew ( 2 flaggers )GI‐27 120.00$          HR4480.00Trail, 4" chipped woodGI‐28 8.00$              SYTrail, 4" crushed cinderGI‐29 9.00$              SYTrail, 4" top courseGI‐30 12.00$            SYConduit, 2"GI‐31 5.00$              LFWall, retaining, concreteGI‐32 55.00$            SFWall, rockeryGI‐33 15.00$            SFSUBTOTAL THIS PAGE:12,829.501,415.00(B)(C)(D)(E)SITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR STREET AND SITE IMPROVEMENTSQuantity Remaining (Bond Reduction) (B)(C)Page 3 of 13Ref 8‐H Bond Quantity WorksheetSECTION II.b TRANSPORTATIONUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 12/18/2020 CED Permit #:########ExistingFuture PublicPrivateRight‐of‐WayImprovementsImprovements(D) (E)DescriptionNo. Unit Price Unit Quant. Cost Quant. Cost Quant. Cost Quant. CostSITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR STREET AND SITE IMPROVEMENTSQuantity Remaining (Bond Reduction) (B)(C)ROAD IMPROVEMENT/PAVEMENT/SURFACINGAC Grinding, 4' wide machine < 1000syRI‐1 30.00$            SYAC Grinding, 4' wide machine 1000‐2000sy RI‐2 16.00$            SYAC Grinding, 4' wide machine > 2000syRI‐3 10.00$            SYAC Removal/DisposalRI‐4 35.00$            SY441,540.00Barricade, Type III ( Permanent )RI‐5 56.00$            LFGuard RailRI‐6 30.00$            LFCurb & Gutter, rolledRI‐7 17.00$            LFCurb & Gutter, verticalRI‐8 12.50$            LF1962,450.00Curb and Gutter, demolition and disposal RI‐9 18.00$            LF781,404.00Curb, extruded asphaltRI‐10 5.50$              LFCurb, extruded concreteRI‐11 7.00$              LFSawcut, asphalt, 3" depthRI‐12 1.85$              LF237438.45Sawcut, concrete, per 1" depthRI‐13 3.00$              LFSealant, asphaltRI‐14 2.00$              LFShoulder, gravel, 4" thickRI‐15 15.00$            SYSidewalk, 4" thickRI‐16 38.00$            SY963,648.00Sidewalk, 4" thick, demolition and disposal RI‐17 32.00$            SYSidewalk, 5" thickRI‐18 41.00$            SYSidewalk, 5" thick, demolition and disposal RI‐19 40.00$            SYSign, Handicap RI‐20 85.00$            EachStriping, per stallRI‐21 7.00$              EachStriping, thermoplastic, ( for crosswalk )RI‐22 3.00$              SFStriping, 4" reflectorized lineRI‐23 0.50$              LFAdditional 2.5" Crushed SurfacingRI‐243.60$              SYHMA 1/2" Overlay 1.5" RI‐25 14.00$            SYHMA 1/2" Overlay 2"RI‐26 18.00$            SY2785,004.00HMA Road, 2", 4" rock, First 2500 SYRI‐27 28.00$            SY3088,624.00HMA Road, 2", 4" rock, Qty. over 2500SY RI‐28 21.00$            SYHMA Road, 4", 6" rock, First 2500 SYRI‐29 45.00$            SYHMA Road, 4", 6" rock, Qty. over 2500 SY RI‐30 37.00$            SYHMA Road, 4", 4.5" ATBRI‐31 38.00$            SYGravel Road, 4" rock, First 2500 SYRI‐32 15.00$            SYGravel Road, 4" rock, Qty. over 2500 SYRI‐33 10.00$            SYThickened EdgeRI‐34 8.60$              LFSUBTOTAL THIS PAGE:23,108.45(B)(C)(D)(E)Page 4 of 13Ref 8‐H Bond Quantity WorksheetSECTION II.b TRANSPORTATIONUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 12/18/2020 CED Permit #:########ExistingFuture PublicPrivateRight‐of‐WayImprovementsImprovements(D) (E)DescriptionNo. Unit Price Unit Quant. Cost Quant. Cost Quant. Cost Quant. CostSITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR STREET AND SITE IMPROVEMENTSQuantity Remaining (Bond Reduction) (B)(C)PARKING LOT SURFACING No.2" AC, 2" top course rock & 4" borrowPL‐1 21.00$            SY2" AC,  1.5"  top course & 2.5" base course PL‐2 28.00$            SY4" select borrowPL‐35.00$              SY1.5" top course rock & 2.5" base coursePL‐4 14.00$            SYSUBTOTAL PARKING LOT SURFACING:(B)(C)(D)(E)LANDSCAPING & VEGETATION No.Street TreesLA‐1Median LandscapingLA‐2Right‐of‐Way LandscapingLA‐3Wetland LandscapingLA‐4SUBTOTAL LANDSCAPING & VEGETATION:(B)(C)(D)(E)TRAFFIC & LIGHTING No.SignsTR‐1Street Light System ( # of Poles)TR‐2Traffic SignalTR‐3Traffic Signal ModificationTR‐4SUBTOTAL TRAFFIC & LIGHTING:(B)(C)(D)(E)WRITE‐IN‐ITEMSSUBTOTAL WRITE‐IN ITEMS:STREET AND SITE IMPROVEMENTS SUBTOTAL:35,937.951,415.00SALES TAX @ 10%3,593.80141.50STREET AND SITE IMPROVEMENTS TOTAL:39,531.751,556.50(B)(C)(D)(E)Page 5 of 13Ref 8‐H Bond Quantity WorksheetSECTION II.b TRANSPORTATIONUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 12/18/2020 CED Permit #:########ExistingFuture PublicPrivateRight‐of‐WayImprovementsImprovements(D) (E)DescriptionNo. Unit Price Unit Quant. Cost Quant. Cost Quant. Cost Quant. CostDRAINAGE (CPE = Corrugated Polyethylene Pipe, N12 or Equivalent) For Culvert prices, Average of 4' cover was assumed. Assume perforated PVC is same price as solid pipe.) Access Road, R/D D‐1 26.00$             SY* (CBs include frame and lid)Beehive D‐2 90.00$             EachThrough‐curb Inlet Framework D‐3 400.00$           EachCB Type ID‐4 1,500.00$       Each 23,000.0023,000.00CB Type IL D‐5 1,750.00$       EachCB Type II, 48" diameter D‐6 2,300.00$       Each     for additional depth over 4'    D‐7 480.00$           FTCB Type II, 54" diameterD‐82,500.00$       Each     for additional depth over 4'D‐9 495.00$           FTCB Type II, 60" diameterD‐10 2,800.00$       Each     for additional depth over 4'D‐11 600.00$           FTCB Type II, 72" diameterD‐12 6,000.00$       Each     for additional depth over 4'D‐13 850.00$           FTCB Type II, 96" diameterD‐14 14,000.00$     Each     for additional depth over 4'D‐15 925.00$           FTTrash Rack, 12"D‐16 350.00$           EachTrash Rack, 15"D‐17 410.00$           EachTrash Rack, 18"D‐18 480.00$           EachTrash Rack, 21"D‐19 550.00$           EachCleanout, PVC, 4"D‐20 150.00$           EachCleanout, PVC, 6"D‐21 170.00$           Each4680.00Cleanout, PVC, 8"D‐22 200.00$           EachCulvert, PVC, 4" D‐23 10.00$             LFCulvert, PVC, 6" D‐24 13.00$             LFCulvert, PVC,  8" D‐25 15.00$             LFCulvert, PVC, 12" D‐26 23.00$             LFCulvert, PVC, 15" D‐27 35.00$             LFCulvert, PVC, 18" D‐28 41.00$             LFCulvert, PVC, 24"D‐29 56.00$             LFCulvert, PVC, 30" D‐30 78.00$             LFCulvert, PVC, 36" D‐31 130.00$           LFCulvert, CMP, 8"D‐32 19.00$             LFCulvert, CMP, 12"D‐33 29.00$             LFSUBTOTAL THIS PAGE:3,000.003,680.00(B)(C)(D)(E)Quantity Remaining (Bond Reduction) (B)(C)SITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR DRAINAGE AND STORMWATER FACILITIESPage 6 of 13Ref 8‐H Bond Quantity WorksheetSECTION II.c DRAINAGEUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 12/18/2020 CED Permit #:########ExistingFuture PublicPrivateRight‐of‐WayImprovementsImprovements(D) (E)DescriptionNo. Unit Price Unit Quant. Cost Quant. Cost Quant. Cost Quant. CostQuantity Remaining (Bond Reduction) (B)(C)SITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR DRAINAGE AND STORMWATER FACILITIESDRAINAGE (Continued)Culvert, CMP, 15" D‐34 35.00$             LFCulvert, CMP, 18" D‐35 41.00$             LFCulvert, CMP, 24" D‐36 56.00$             LFCulvert, CMP, 30" D‐37 78.00$             LFCulvert, CMP, 36" D‐38 130.00$           LFCulvert, CMP, 48" D‐39 190.00$           LFCulvert, CMP, 60" D‐40 270.00$           LFCulvert, CMP, 72" D‐41 350.00$           LFCulvert, Concrete, 8"D‐42 42.00$             LFCulvert, Concrete, 12"D‐43 48.00$             LFCulvert, Concrete, 15" D‐44 78.00$             LFCulvert, Concrete, 18"D‐45 48.00$             LFCulvert, Concrete, 24"D‐46 78.00$             LFCulvert, Concrete, 30"D‐47 125.00$           LFCulvert, Concrete, 36"D‐48 150.00$           LFCulvert, Concrete, 42"D‐49 175.00$           LFCulvert, Concrete, 48"D‐50 205.00$           LFCulvert, CPE Triple Wall, 6" D‐51 14.00$             LFCulvert, CPE Triple Wall, 8" D‐52 16.00$             LFCulvert, CPE Triple Wall, 12" D‐53 24.00$             LFCulvert, CPE Triple Wall, 15" D‐54 35.00$             LFCulvert, CPE Triple Wall, 18" D‐55 41.00$             LFCulvert, CPE Triple Wall, 24" D‐56 56.00$             LFCulvert, CPE Triple Wall, 30" D‐57 78.00$             LFCulvert, CPE Triple Wall, 36" D‐58 130.00$           LFCulvert, LCPE, 6"D‐5960.00$             LFCulvert, LCPE, 8"D‐60 72.00$             LFCulvert, LCPE, 12"D‐61 84.00$             LFCulvert, LCPE, 15"D‐62 96.00$             LFCulvert, LCPE, 18"D‐63 108.00$           LFCulvert, LCPE, 24"D‐64 120.00$           LFCulvert, LCPE, 30"D‐65 132.00$           LFCulvert, LCPE, 36"D‐66 144.00$           LFCulvert, LCPE, 48"D‐67 156.00$           LFCulvert, LCPE, 54"D‐68 168.00$           LFSUBTOTAL THIS PAGE:(B)(C)(D)(E)Page 7 of 13Ref 8‐H Bond Quantity WorksheetSECTION II.c DRAINAGEUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 12/18/2020 CED Permit #:########ExistingFuture PublicPrivateRight‐of‐WayImprovementsImprovements(D) (E)DescriptionNo. Unit Price Unit Quant. Cost Quant. Cost Quant. Cost Quant. CostQuantity Remaining (Bond Reduction) (B)(C)SITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR DRAINAGE AND STORMWATER FACILITIESDRAINAGE (Continued)Culvert, LCPE, 60" D‐69 180.00$           LFCulvert, LCPE, 72" D‐70 192.00$           LFCulvert, HDPE, 6" D‐71 42.00$             LFCulvert, HDPE, 8" D‐72 42.00$             LFCulvert, HDPE, 12" D‐73 74.00$             LFCulvert, HDPE, 15" D‐74 106.00$           LFCulvert, HDPE, 18" D‐75 138.00$           LFCulvert, HDPE, 24" D‐76 221.00$           LFCulvert, HDPE, 30" D‐77 276.00$           LFCulvert, HDPE, 36" D‐78 331.00$           LFCulvert, HDPE, 48" D‐79 386.00$           LFCulvert, HDPE, 54" D‐80 441.00$           LFCulvert, HDPE, 60" D‐81 496.00$           LFCulvert, HDPE, 72" D‐82 551.00$           LFPipe, Polypropylene, 6" D‐83 84.00$             LF 1109,240.00Pipe, Polypropylene, 8" D‐84 89.00$             LFPipe, Polypropylene, 12" D‐85 95.00$             LF 323,040.00Pipe, Polypropylene, 15" D‐86 100.00$           LFPipe, Polypropylene, 18" D‐87 106.00$           LFPipe, Polypropylene, 24" D‐88 111.00$           LFPipe, Polypropylene, 30" D‐89 119.00$           LFPipe, Polypropylene, 36" D‐90 154.00$           LFPipe, Polypropylene, 48" D‐91 226.00$           LFPipe, Polypropylene, 54" D‐92 332.00$           LFPipe, Polypropylene, 60" D‐93 439.00$           LFPipe, Polypropylene, 72" D‐94 545.00$           LFCulvert, DI, 6" D‐95 61.00$             LFCulvert, DI, 8" D‐96 84.00$             LFCulvert, DI, 12" D‐97 106.00$           LFCulvert, DI, 15" D‐98 129.00$           LFCulvert, DI, 18"D‐99 152.00$           LFCulvert, DI, 24"D‐100 175.00$           LFCulvert, DI, 30"D‐101 198.00$           LFCulvert, DI, 36"D‐102 220.00$           LFCulvert, DI, 48"D‐103 243.00$           LFCulvert, DI, 54"D‐104 266.00$           LFCulvert, DI, 60"D‐105 289.00$           LFCulvert, DI, 72"D‐106 311.00$           LFSUBTOTAL THIS PAGE:3,040.009,240.00(B)(C)(D)(E)Page 8 of 13Ref 8‐H Bond Quantity WorksheetSECTION II.c DRAINAGEUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 12/18/2020 CED Permit #:########ExistingFuture PublicPrivateRight‐of‐WayImprovementsImprovements(D) (E)DescriptionNo. Unit Price Unit Quant. Cost Quant. Cost Quant. Cost Quant. CostQuantity Remaining (Bond Reduction) (B)(C)SITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR DRAINAGE AND STORMWATER FACILITIESSpecialty Drainage ItemsDitching SD‐19.50$               CYFlow Dispersal Trench    (1,436 base+)SD‐3 28.00$             LF    French Drain  (3' depth)SD‐4 26.00$             LFGeotextile, laid in trench, polypropylene SD‐53.00$               SYMid‐tank Access Riser, 48" dia,  6' deep SD‐6 2,000.00$       EachPond Overflow SpillwaySD‐7 16.00$             SYRestrictor/Oil Separator, 12"SD‐8 1,150.00$       EachRestrictor/Oil Separator, 15"SD‐9 1,350.00$       EachRestrictor/Oil Separator, 18"SD‐10 1,700.00$       EachRiprap, placedSD‐11 42.00$             CYTank End Reducer (36" diameter)SD‐12 1,200.00$       EachInfiltration pond testingSD‐13 125.00$           HRPermeable PavementSD‐14Permeable Concrete SidewalkSD‐15Culvert, Box      __ ft  x  __ ftSD‐16SUBTOTAL SPECIALTY DRAINAGE ITEMS:(B)(C)(D)(E)STORMWATER FACILITIES (Include Flow Control and Water Quality Facility Summary Sheet and Sketch)Detention Pond SF‐1Each Detention Tank SF‐2Each Detention Vault SF‐3 60,000.00$     Each 160,000.00Infiltration Pond SF‐4Each Infiltration Tank SF‐5Each Infiltration Vault SF‐6Each Infiltration Trenches SF‐7 15,200.00$     Each 115,200.00Basic Biofiltration Swale SF‐8Each Wet Biofiltration Swale SF‐9Each Wetpond SF‐10 Each Wetvault SF‐11 Each Sand Filter SF‐12 Each Sand Filter Vault SF‐13 Each Linear Sand Filter SF‐14 Each Proprietary Facility SF‐15Each Bioretention FacilitySF‐16Each SUBTOTAL STORMWATER FACILITIES:60,000.0015,200.00(B)(C)(D)(E)Page 9 of 13Ref 8‐H Bond Quantity WorksheetSECTION II.c DRAINAGEUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 12/18/2020 CED Permit #:########ExistingFuture PublicPrivateRight‐of‐WayImprovementsImprovements(D) (E)DescriptionNo. Unit Price Unit Quant. Cost Quant. Cost Quant. Cost Quant. CostQuantity Remaining (Bond Reduction) (B)(C)SITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR DRAINAGE AND STORMWATER FACILITIESWRITE‐IN‐ITEMS (INCLUDE ON‐SITE BMPs)WI‐1WI‐2WI‐3WI‐4WI‐5WI‐6WI‐7WI‐8WI‐9WI‐10WI‐11WI‐12WI‐13WI‐14WI‐15SUBTOTAL WRITE‐IN ITEMS:DRAINAGE AND STORMWATER FACILITIES SUBTOTAL: 66,040.00 28,120.00SALES TAX @ 10% 6,604.00 2,812.00DRAINAGE AND STORMWATER FACILITIES TOTAL: 72,644.00 30,932.00(B)(C)(D)(E)Page 10 of 13Ref 8‐H Bond Quantity WorksheetSECTION II.c DRAINAGEUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 12/18/2020 CED Permit #:########ExistingFuture PublicPrivateRight‐of‐WayImprovementsImprovements(D) (E)DescriptionNo. Unit Price Unit Quant. Cost Quant. Cost Quant. Cost Quant. CostConnection to Existing WatermainW‐1 2,000.00$      EachDuctile Iron Watermain, CL 52, 4 Inch Diameter W‐2 50.00$            LFDuctile Iron Watermain, CL 52, 6 Inch Diameter W‐3 56.00$            LFDuctile Iron Watermain, CL 52, 8 Inch Diameter W‐4 60.00$            LFDuctile Iron Watermain, CL 52, 10 Inch Diameter W‐5 70.00$            LFDuctile Iron Watermain, CL 52, 12 Inch Diameter W‐6 80.00$            LFGate Valve, 4 inch DiameterW‐7 500.00$          EachGate Valve, 6 inch DiameterW‐8 700.00$          EachGate Valve, 8 Inch DiameterW‐9 800.00$          EachGate Valve, 10 Inch DiameterW‐10 1,000.00$      EachGate Valve, 12 Inch DiameterW‐11 1,200.00$      EachFire Hydrant AssemblyW‐12 4,000.00$      EachPermanent Blow‐Off AssemblyW‐13 1,800.00$      EachAir‐Vac Assembly,  2‐Inch DiameterW‐14 2,000.00$      EachAir‐Vac Assembly,  1‐Inch DiameterW‐15 1,500.00$      EachCompound Meter Assembly 3‐inch Diameter W‐16 8,000.00$      EachCompound Meter Assembly 4‐inch Diameter W‐17 9,000.00$      EachCompound Meter Assembly 6‐inch Diameter W‐18 10,000.00$    EachPressure Reducing Valve Station 8‐inch to 10‐inch W‐19 20,000.00$    EachWATER SUBTOTAL:SALES TAX @ 10%WATER TOTAL:(B)(C)(D)(E)SITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR WATERQuantity Remaining (Bond Reduction) (B)(C)Page 11 of 13Ref 8‐H Bond Quantity WorksheetSECTION II.d WATERUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 12/18/2020 CED Permit #:########ExistingFuture PublicPrivateRight‐of‐WayImprovementsImprovements(D) (E)DescriptionNo. Unit Price Unit Quant. Cost Quant. Cost Quant. Cost Quant. CostClean OutsSS‐1 1,000.00$      Each22,000.00Grease Interceptor, 500 gallonSS‐2 8,000.00$      EachGrease Interceptor, 1000 gallonSS‐3 10,000.00$    EachGrease Interceptor, 1500 gallonSS‐4 15,000.00$    EachSide Sewer Pipe, PVC. 4 Inch DiameterSS‐5 80.00$            LF1008,000.00Side Sewer Pipe, PVC. 6 Inch DiameterSS‐6 95.00$            LFSewer Pipe, PVC, 8 inch DiameterSS‐7 105.00$          LFSewer Pipe, PVC, 12 Inch DiameterSS‐8 120.00$          LFSewer Pipe, DI, 8 inch DiameterSS‐9 115.00$          LFSewer Pipe, DI, 12 Inch DiameterSS‐10 130.00$          LFManhole, 48 Inch DiameterSS‐11 6,000.00$      EachManhole, 54 Inch DiameterSS‐13 6,500.00$      EachManhole, 60 Inch DiameterSS‐15 7,500.00$      EachManhole, 72 Inch DiameterSS‐17 8,500.00$      EachManhole, 96 Inch DiameterSS‐19 14,000.00$    EachPipe, C‐900, 12 Inch DiameterSS‐21 180.00$          LFOutside DropSS‐24 1,500.00$      LSInside DropSS‐25 1,000.00$      LSSewer Pipe, PVC, ____ Inch DiameterSS‐26Lift Station (Entire System)SS‐27LSSANITARY SEWER SUBTOTAL:10,000.00SALES TAX @ 10%1,000.00SANITARY SEWER TOTAL:11,000.00(B)(C)(D)(E)SITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR SANITARY SEWERQuantity Remaining (Bond Reduction) (B)(C)Page 12 of 13Ref 8‐H Bond Quantity WorksheetSECTION II.e SANITARY SEWERUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 12/18/2020 Planning Division |1055 South Grady Way – 6th Floor | Renton, WA 98057 (425) 430‐7200Date:Name:Project Name: PE Registration No:CED Plan # (LUA):Firm Name:CED Permit # (U):Firm Address:Site Address:Phone No.Parcel #(s):Email Address:Project Phase: Site Restoration/Erosion Sediment Control Subtotal (a)Existing Right‐of‐Way Improvements Subtotal (b) (b)‐$                                                               Future Public Improvements Subtotal(c)39,531.75$                                                   Stormwater & Drainage Facilities (Public & Private) Subtotal(d) (d)103,576.00$                                                 (e)(f)Site RestorationCivil Construction PermitMaintenance Bond28,621.55$                                                   Bond Reduction2Construction Permit Bond Amount 3Minimum Bond Amount is $10,000.001 Estimate Only  ‐ May involve multiple and variable components, which will be established on an individual basis by Development Engineering.2 The City of Renton allows one request only for bond reduction prior to the maintenance period. Reduction of not more than 70% of the original bond amount, provided that the remaining 30% willcover all remaining items to be constructed. 3 Required Bond Amounts are subject to review and modification by Development Engineering.* Note: The word BOND as used in this document means any financial guarantee acceptable to the City of Renton.** Note: All prices include labor, equipment, materials, overhead and profit. EST1((b) + (c) + (d)) x 20%‐$                                                           MAINTENANCE BOND */**(after final acceptance of construction)7,054.30$                                                 ‐$                                                           103,576.00$                                            7,054.30$                                                 ‐$                                                           103,576.00$                                            ‐$                                                           110,630.30$                                            P (a) x 100%SITE IMPROVEMENT BOND QUANTITY WORKSHEET BOND CALCULATIONS12/18/2020Sheri Murata41846Core Design Inc.R((b x 150%) + (d x 100%))S(e) x 150% + (f) x 100%Bond Reduction: Existing Right‐of‐Way Improvements (Quantity Remaining)2Bond Reduction: Stormwater & Drainage Facilities (Quantity Remaining)2T(P +R ‐ S)Prepared by:Project InformationCONSTRUCTION BOND AMOUNT */**(prior to permit issuance)425.885.7877shm@coredesigninc.comNE 24th STREET SHORT PLAT19‐0000624709 NE 24th St., Renton, WA 980590323059245FOR APPROVAL########12100 NE 195th St, Suite #300, Bothell, WA 98011Page 13 of 13Ref 8‐H Bond Quantity WorksheetSECTION III. BOND WORKSHEETUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 12/18/2020 2016 KING COUNTY SURFACE WATER DESIGN MANUAL, REFERENCE D 4/24/2016 Page 1 STORMWATER FACILITY SUMMARY SHEET DPER Permit No.___________________ (provide one Stormwater Facility Summary Sheet per Natural Discharge Location)Date ___________________ OVERVIEW:NPDES Permit No.___________________ Project Name Parcel No.____________________________ Project Location Retired Parcel No.____________________________ Downstream Drainage Basins:Project includes Landscape Management Plan?yes Major Basin Name ______________________________________________(include copy with TIR as Appendix)no Immediate Basin Name ______________________________________________ GENERAL FACILITY INFORMATION: Leachable Metals Infiltration Impervious Surface Limit Type # of Type # of Type # of facilities Flow Control BMPs Ponds ______ Ponds ______ Ponds ______ Basic Clearing Limit Vaults ______ Tanks ______ Vaults ______ Conservation Drainage Facility Tanks ______ Trenches _____ Tanks ______ Flood Problem Landscape Management Plan If no flow control facility, check one: Project qualifies for KCSWDM Exemption (KCSWDM 1.2.3): Basic Exemption (Applies to Commercial parcels only)Area % of Total Redevelopment projects Cost Exemption for Parcel Redevelopment projects Direct Discharge Exemption Other _____________________ Total impervious surface served by Project qualifies for 0.1 cfs Exception per KCSWDM 1.2.3 flow control facility(ies) (sq ft) Impervious surface served by flow KCSWDM Adjustment No. ___________________control facility(ies) designed 1990 or later (sq ft) approved KCSWDM Adjustment No. __________________ Impervious surface served by Shared Facility Name/Location: _________________________ pervious surface absorption (sq ft) No flow control required (other, provide justification): Impervious surface served by approved ____________________________________________________ water quality facility(ies) (sq ft) Flow Control Performance Std Declarations of Covenant Recording No. Water QualityDetention TREATMENT SUMMARY FOR TOTAL IMPERVIOUS SURFACES ----- Total Impervious Acreage (ac) No flow control required per approved Flow control provided in regional/shared facility per approved PROVIDE FACILITY DETAILS AND FACILITY SKETCH FOR EACH FACILITY ON REVERSE. USE ADDITIONAL SHEETS AS NEEDED FOR ADDITIONAL FACILITIES Impervious Surface Exemption for Transportation Total Acreage (ac) 2016 KING COUNTY SURFACE WATER DESIGN MANUAL, REFERENCE D 4/24/2016 Page 2 STORMWATER FACILITY SUMMARY SHEET DPER Permit No.___________________ (provide one Stormwater Facility Summary Sheet per Natural Discharge Location) Project Name Downstream Drainage Basins: Major Basin Name _______________________________ Project Location Immediate Basin Name ___________________________ FLOW CONTROL FACILITY:Basin: Facility Name/Number _______________________________________ New Facility Project Impervious Facility Location ____________________________________________ Existing Facility Acres Served ________ UIC? □ yes □ no UIC Site ID:% of Total Project Impervious cu.ft.Volume Factor Acres Served ________ _____________ ac.ft.____________of Safety _______No. of Lots Served ________ Control Structure location: _______________________________________________ Type of Control Structure:No. of Orifices/Restrictions __________ Riser in vault Size of Orifice/Restriction (in.) No.1 ______ cu.ft. Riser in Type II CB (numbered starting with lowest No.2 ______ ac.ft. Weir in Type II CB orifice): No.3 ______ (inches in decimal format)No.4 ______ WATER QUALITY FACILITIES Design Information Indicate no. of water quality facilities/BMPs for each type:Water Quality design flow (cfs) _______Flow dispersion Water Quality treated volume (sandfilter) (cu.ft.) _______Filter strip Water Quality storage volume (wetpool) (cu.ft.) _______Biofiltration swale regular, wet or Landscape management plan Farm management plan continuous inflow _______Wetvault combined w/detention ______High flow bypass structure (e.g., flow-splitter catch basin) _______Wetpond basic large combined w/detention ______Oil/water separator baffle coalescing plate _______Pre-settling pond ______Storm filter _______Stormwater wetland ______Pre-settling structure (Manufacturer:______________________) _______Sand filter basic large Sand bed depth ______Catch basin inserts (Manufacturer:________________________) regular linear vault (inches)______________Source controls _________________________________________ ● Is facility lined? yes no If so, what marker is used above liner?_____________________________________________________ Facility Summary Sheet Sketch: All detention, infiltration and water quality facilities must include a detailed sketch (11"x17" reduced size plan sheets preferred). Dam Safety Regulations (WA State Dept of Ecology): Reservoir Volume above natural grade Depth of Reservoir above natural grade (ft) Live Storage Volume Live Storage Depth (ft) Core Design, Inc. NE 24th STREET SHORT PLAT Page 47 10 OPERATIONS AND MAINTENANCE The operations and maintenance information will be provided with the Utilities Permit through select portions from Appendix A of the 2017 RSWDM and Utility Permit plan set. CITY OF RENTON SURFACE WATER DESIGN MANUAL 2017 City of Renton Surface Water Design Manual 12/12/2016 A-1 APPENDIX A MAINTENANCE REQUIREMENTS FOR STORMWATER FACILITIES AND ON-SITE BMPS This appendix contains the maintenance requirements for the following typical stormwater flow control and water quality facilities and on-site BMPs (ctrl/click the title to follow the link): No. 1 – Detention Ponds No. 2 – Infiltration Facilities No. 3 – Detention Tanks and Vaults No. 4 – Control Structure/Flow Restrictor No. 5 – Catch Basins and Manholes No. 6 – Conveyance Pipes and Ditches No. 7 – Debris Barriers (e.g., trash racks) No. 8 – Energy Dissipaters No. 9 – Fencing No. 10 – Gates/Bollards/Access Barriers No. 11 – Grounds (landscaping) No. 12 – Access Roads No. 13 – Basic Bioswale (grass) No. 14 – Wet Bioswale No. 15 – Filter Strip No. 16 – Wetpond No. 17 – Wetvault No. 18 – Stormwater Wetland No. 19 – Sand Filter Pond No. 20 – Sand Filter Vault No. 21 – Proprietary Facility Cartridge Filter Systems No. 22 – Baffle Oil/Water Separator No. 23 – Coalescing Plate Oil/Water Separator APPENDIX A MAINTENANCE REQUIREMENTS FOR STORMWATER FACILITIES AND ON-SITE BMPS 12/12/2016 2017 City of Renton Surface Water Design Manual A-2 No. 24 – Catch Basin Insert (not allowed in the city for oil control) No. 25 – Drywell BMP No. 26 – Gravel Filled Infiltration Trench BMP No. 27 – Gravel Filled Dispersion Trench BMP No. 28 – Native Vegetated Surface/Native Vegetated Landscape BMP No. 29 – Perforated Pipe Connections BMP No. 30 – Permeable Pavement BMP No. 31 – Bioretention BMP No. 32 – RainWater Harvesting BMP No. 33 – Rock Pad BMP No. 34 – Sheet Flow BMP No. 35 – Splash Block BMP No. 36 – Vegetated Roof BMP No. 37 – Rain Garden BMP No. 38 – Soil Amendment BMP No. 39 – Retained Trees No. 40 – Filterra System No. 41 – Compost Amended Vegetated Filter Strip (CAVFS) No. 42 – Media Filter Drain (MFD) No. 43 – Compost-Amended Biofiltration Swale APPENDIX A MAINTENANCE REQUIREMENTS FOR STORMWATER FACILITIES AND ON-SITE BMPS 12/12/2016 2017 City of Renton Surface Water Design Manual A-6 NO. 3 – DETENTION TANKS AND VAULTS MAINTENANCE COMPONENT DEFECT OR PROBLEM CONDITIONS WHEN MAINTENANCE IS NEEDED RESULTS EXPECTED WHEN MAINTENANCE IS PERFORMED Site Trash and debris Any trash and debris which exceed 1 cubic foot per 1,000 square feet (this is about equal to the amount of trash it would take to fill up one standard size office garbage can). In general, there should be no visual evidence of dumping. Trash and debris cleared from site. Noxious weeds Any noxious or nuisance vegetation which may constitute a hazard to City personnel or the public. Noxious and nuisance vegetation removed according to applicable regulations. No danger of noxious vegetation where City personnel or the public might normally be. Contaminants and pollution Any evidence of contaminants or pollution such as oil, gasoline, concrete slurries or paint. Materials removed and disposed of according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Excessive growth of grass/groundcover Grass or groundcover exceeds 18 inches in height. Grass or groundcover mowed to a height no greater than 6 inches. Tank or Vault Storage Area Trash and debris Any trash and debris accumulated in vault or tank (includes floatables and non-floatables). No trash or debris in vault. Sediment accumulation Accumulated sediment depth exceeds 10% of the diameter of the storage area for ½ length of storage vault or any point depth exceeds 15% of diameter. Example: 72-inch storage tank would require cleaning when sediment reaches depth of 7 inches for more than ½ length of tank. All sediment removed from storage area. Tank Structure Plugged air vent Any blockage of the vent. Tank or vault freely vents. Tank bent out of shape Any part of tank/pipe is bent out of shape more than 10% of its design shape. Tank repaired or replaced to design. Gaps between sections, damaged joints or cracks or tears in wall A gap wider than ½-inch at the joint of any tank sections or any evidence of soil particles entering the tank at a joint or through a wall. No water or soil entering tank through joints or walls. Vault Structure Damage to wall, frame, bottom, and/or top slab Cracks wider than ½-inch, any evidence of soil entering the structure through cracks or qualified inspection personnel determines that the vault is not structurally sound. Vault is sealed and structurally sound. Inlet/Outlet Pipes Sediment accumulation Sediment filling 20% or more of the pipe. Inlet/outlet pipes clear of sediment. Trash and debris Trash and debris accumulated in inlet/outlet pipes (includes floatables and non-floatables). No trash or debris in pipes. Damaged inlet/outlet pipes Cracks wider than ½-inch at the joint of the inlet/outlet pipes or any evidence of soil entering at the joints of the inlet/outlet pipes. No cracks more than ¼-inch wide at the joint of the inlet/outlet pipe. Access Manhole Cover/lid not in place Cover/lid is missing or only partially in place. Any open manhole requires immediate maintenance. Manhole access covered. APPENDIX A MAINTENANCE REQUIREMENTS FOR STORMWATER FACILITIES AND ON-SITE BMPS 2017 City of Renton Surface Water Design Manual 12/12/2016 A-7 NO. 3 – DETENTION TANKS AND VAULTS MAINTENANCE COMPONENT DEFECT OR PROBLEM CONDITIONS WHEN MAINTENANCE IS NEEDED RESULTS EXPECTED WHEN MAINTENANCE IS PERFORMED Access Manhole (cont.) Locking mechanism not working Mechanism cannot be opened by one maintenance person with proper tools. Bolts cannot be seated. Self-locking cover/lid does not work. Mechanism opens with proper tools. Cover/lid difficult to remove One maintenance person cannot remove cover/lid after applying 80 lbs of lift. Cover/lid can be removed and reinstalled by one maintenance person. Ladder rungs unsafe Missing rungs, misalignment, rust, or cracks. Ladder meets design standards. Allows maintenance person safe access. Large access doors/plate Damaged or difficult to open Large access doors or plates cannot be opened/removed using normal equipment. Replace or repair access door so it can opened as designed. Gaps, doesn't cover completely Large access doors not flat and/or access opening not completely covered. Doors close flat; covers access opening completely. Lifting rings missing, rusted Lifting rings not capable of lifting weight of door or plate. Lifting rings sufficient to lift or remove door or plate. APPENDIX A MAINTENANCE REQUIREMENTS FOR STORMWATER FACILITIES AND ON-SITE BMPS 12/12/2016 2017 City of Renton Surface Water Design Manual A-8 NO. 4 – CONTROL STRUCTURE/FLOW RESTRICTOR MAINTENANCE COMPONENT DEFECT OR PROBLEM CONDITION WHEN MAINTENANCE IS NEEDED RESULTS EXPECTED WHEN MAINTENANCE IS PERFORMED Structure Trash and debris Trash or debris of more than ½ cubic foot which is located immediately in front of the structure opening or is blocking capacity of the structure by more than 10%. No Trash or debris blocking or potentially blocking entrance to structure. Trash or debris in the structure that exceeds 1/3 the depth from the bottom of basin to invert the lowest pipe into or out of the basin. No trash or debris in the structure. Deposits of garbage exceeding 1 cubic foot in volume. No condition present which would attract or support the breeding of insects or rodents. Sediment accumulation Sediment exceeds 60% of the depth from the bottom of the structure to the invert of the lowest pipe into or out of the structure or the bottom of the FROP-T section or is within 6 inches of the invert of the lowest pipe into or out of the structure or the bottom of the FROP-T section. Sump of structure contains no sediment. Damage to frame and/or top slab Corner of frame extends more than ¾ inch past curb face into the street (If applicable). Frame is even with curb. Top slab has holes larger than 2 square inches or cracks wider than ¼ inch. Top slab is free of holes and cracks. Frame not sitting flush on top slab, i.e., separation of more than ¾ inch of the frame from the top slab. Frame is sitting flush on top slab. Cracks in walls or bottom Cracks wider than ½ inch and longer than 3 feet, any evidence of soil particles entering structure through cracks, or maintenance person judges that structure is unsound. Structure is sealed and structurally sound. Cracks wider than ½ inch and longer than 1 foot at the joint of any inlet/outlet pipe or any evidence of soil particles entering structure through cracks. No cracks more than 1/4 inch wide at the joint of inlet/outlet pipe. Settlement/ misalignment Structure has settled more than 1 inch or has rotated more than 2 inches out of alignment. Basin replaced or repaired to design standards. Damaged pipe joints Cracks wider than ½-inch at the joint of the inlet/outlet pipes or any evidence of soil entering the structure at the joint of the inlet/outlet pipes. No cracks more than ¼-inch wide at the joint of inlet/outlet pipes. Contaminants and pollution Any evidence of contaminants or pollution such as oil, gasoline, concrete slurries or paint. Materials removed and disposed of according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Ladder rungs missing or unsafe Ladder is unsafe due to missing rungs, misalignment, rust, cracks, or sharp edges. Ladder meets design standards and allows maintenance person safe access. FROP-T Section Damaged FROP-T T section is not securely attached to structure wall and outlet pipe structure should support at least 1,000 lbs of up or down pressure. T section securely attached to wall and outlet pipe. Structure is not in upright position (allow up to 10% from plumb). Structure in correct position. APPENDIX A MAINTENANCE REQUIREMENTS FOR STORMWATER FACILITIES AND ON-SITE BMPS 2017 City of Renton Surface Water Design Manual 12/12/2016 A-9 NO. 4 – CONTROL STRUCTURE/FLOW RESTRICTOR MAINTENANCE COMPONENT DEFECT OR PROBLEM CONDITION WHEN MAINTENANCE IS NEEDED RESULTS EXPECTED WHEN MAINTENANCE IS PERFORMED FROP-T Section (cont.) Damaged FROP-T (cont.) Connections to outlet pipe are not watertight or show signs of deteriorated grout. Connections to outlet pipe are water tight; structure repaired or replaced and works as designed. Any holes—other than designed holes—in the structure. Structure has no holes other than designed holes. Cleanout Gate Damaged or missing cleanout gate Cleanout gate is missing. Replace cleanout gate. Cleanout gate is not watertight. Gate is watertight and works as designed. Gate cannot be moved up and down by one maintenance person. Gate moves up and down easily and is watertight. Chain/rod leading to gate is missing or damaged. Chain is in place and works as designed. Orifice Plate Damaged or missing orifice plate Control device is not working properly due to missing, out of place, or bent orifice plate. Plate is in place and works as designed. Obstructions to orifice plate Any trash, debris, sediment, or vegetation blocking the plate. Plate is free of all obstructions and works as designed. Overflow Pipe Obstructions to overflow pipe Any trash or debris blocking (or having the potential of blocking) the overflow pipe. Pipe is free of all obstructions and works as designed. Deformed or damaged lip of overflow pipe Lip of overflow pipe is bent or deformed. Overflow pipe does not allow overflow at an elevation lower than design Inlet/Outlet Pipe Sediment accumulation Sediment filling 20% or more of the pipe. Inlet/outlet pipes clear of sediment. Trash and debris Trash and debris accumulated in inlet/outlet pipes (includes floatables and non-floatables). No trash or debris in pipes. Damaged inlet/outlet pipe Cracks wider than ½-inch at the joint of the inlet/outlet pipes or any evidence of soil entering at the joints of the inlet/outlet pipes. No cracks more than ¼-inch wide at the joint of the inlet/outlet pipe. Metal Grates (If applicable) Unsafe grate opening Grate with opening wider than 7/8 inch. Grate opening meets design standards. Trash and debris Trash and debris that is blocking more than 20% of grate surface. Grate free of trash and debris. footnote to guidelines for disposal Damaged or missing grate Grate missing or broken member(s) of the grate. Grate is in place and meets design standards. Manhole Cover/Lid Cover/lid not in place Cover/lid is missing or only partially in place. Any open structure requires urgent maintenance. Cover/lid protects opening to structure. Locking mechanism not working Mechanism cannot be opened by one maintenance person with proper tools. Bolts cannot be seated. Self-locking cover/lid does not work. Mechanism opens with proper tools. Cover/lid difficult to remove One maintenance person cannot remove cover/lid after applying 80 lbs. of lift. Cover/lid can be removed and reinstalled by one maintenance person. APPENDIX A MAINTENANCE REQUIREMENTS FOR STORMWATER FACILITIES AND ON-SITE BMPS 12/12/2016 2017 City of Renton Surface Water Design Manual A-10 NO. 5 – CATCH BASINS AND MANHOLES MAINTENANCE COMPONENT DEFECT OR PROBLEM CONDITION WHEN MAINTENANCE IS NEEDED RESULTS EXPECTED WHEN MAINTENANCE IS PERFORMED Structure Sediment accumulation Sediment exceeds 60% of the depth from the bottom of the catch basin to the invert of the lowest pipe into or out of the catch basin or is within 6 inches of the invert of the lowest pipe into or out of the catch basin. Sump of catch basin contains no sediment. Trash and debris Trash or debris of more than ½ cubic foot which is located immediately in front of the catch basin opening or is blocking capacity of the catch basin by more than 10%. No Trash or debris blocking or potentially blocking entrance to catch basin. Trash or debris in the catch basin that exceeds 1/3 the depth from the bottom of basin to invert the lowest pipe into or out of the basin. No trash or debris in the catch basin. Dead animals or vegetation that could generate odors that could cause complaints or dangerous gases (e.g., methane). No dead animals or vegetation present within catch basin. Deposits of garbage exceeding 1 cubic foot in volume. No condition present which would attract or support the breeding of insects or rodents. Damage to frame and/or top slab Corner of frame extends more than ¾ inch past curb face into the street (If applicable). Frame is even with curb. Top slab has holes larger than 2 square inches or cracks wider than ¼ inch. Top slab is free of holes and cracks. Frame not sitting flush on top slab, i.e., separation of more than ¾ inch of the frame from the top slab. Frame is sitting flush on top slab. Cracks in walls or bottom Cracks wider than ½ inch and longer than 3 feet, any evidence of soil particles entering catch basin through cracks, or maintenance person judges that catch basin is unsound. Catch basin is sealed and is structurally sound. Cracks wider than ½ inch and longer than 1 foot at the joint of any inlet/outlet pipe or any evidence of soil particles entering catch basin through cracks. No cracks more than 1/4 inch wide at the joint of inlet/outlet pipe. Settlement/ misalignment Catch basin has settled more than 1 inch or has rotated more than 2 inches out of alignment. Basin replaced or repaired to design standards. Damaged pipe joints Cracks wider than ½-inch at the joint of the inlet/outlet pipes or any evidence of soil entering the catch basin at the joint of the inlet/outlet pipes. No cracks more than ¼-inch wide at the joint of inlet/outlet pipes. Contaminants and pollution Any evidence of contaminants or pollution such as oil, gasoline, concrete slurries or paint. Materials removed and disposed of according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Inlet/Outlet Pipe Sediment accumulation Sediment filling 20% or more of the pipe. Inlet/outlet pipes clear of sediment. Trash and debris Trash and debris accumulated in inlet/outlet pipes (includes floatables and non-floatables). No trash or debris in pipes. APPENDIX A MAINTENANCE REQUIREMENTS FOR STORMWATER FACILITIES AND ON-SITE BMPS 2017 City of Renton Surface Water Design Manual 12/12/2016 A-11 NO. 5 – CATCH BASINS AND MANHOLES MAINTENANCE COMPONENT DEFECT OR PROBLEM CONDITION WHEN MAINTENANCE IS NEEDED RESULTS EXPECTED WHEN MAINTENANCE IS PERFORMED Inlet/Outlet Pipe (cont.) Damaged inlet/outlet pipe Cracks wider than ½-inch at the joint of the inlet/outlet pipes or any evidence of soil entering at the joints of the inlet/outlet pipes. No cracks more than ¼-inch wide at the joint of the inlet/outlet pipe. Metal Grates (Catch Basins) Unsafe grate opening Grate with opening wider than 7/8 inch. Grate opening meets design standards. Trash and debris Trash and debris that is blocking more than 20% of grate surface. Grate free of trash and debris. footnote to guidelines for disposal Damaged or missing grate Grate missing or broken member(s) of the grate. Any open structure requires urgent maintenance. Grate is in place and meets design standards. Manhole Cover/Lid Cover/lid not in place Cover/lid is missing or only partially in place. Any open structure requires urgent maintenance. Cover/lid protects opening to structure. Locking mechanism not working Mechanism cannot be opened by one maintenance person with proper tools. Bolts cannot be seated. Self-locking cover/lid does not work. Mechanism opens with proper tools. Cover/lid difficult to remove One maintenance person cannot remove cover/lid after applying 80 lbs. of lift. Cover/lid can be removed and reinstalled by one maintenance person. APPENDIX A MAINTENANCE REQUIREMENTS FOR STORMWATER FACILITIES AND ON-SITE BMPS 12/12/2016 2017 City of Renton Surface Water Design Manual A-12 NO. 6 – CONVEYANCE PIPES AND DITCHES MAINTENANCE COMPONENT DEFECT OR PROBLEM CONDITIONS WHEN MAINTENANCE IS NEEDED RESULTS EXPECTED WHEN MAINTENANCE IS PERFORMED Pipes Sediment & debris accumulation Accumulated sediment or debris that exceeds 20% of the diameter of the pipe. Water flows freely through pipes. Vegetation/root growth in pipe Vegetation/roots that reduce free movement of water through pipes. Water flows freely through pipes. Contaminants and pollution Any evidence of contaminants or pollution such as oil, gasoline, concrete slurries or paint. Materials removed and disposed of according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Damage to protective coating or corrosion Protective coating is damaged; rust or corrosion is weakening the structural integrity of any part of pipe. Pipe repaired or replaced. Damaged pipes Any dent that decreases the cross section area of pipe by more than 20% or is determined to have weakened structural integrity of the pipe. Pipe repaired or replaced. Ditches Trash and debris Trash and debris exceeds 1 cubic foot per 1,000 square feet of ditch and slopes. Trash and debris cleared from ditches. Sediment accumulation Accumulated sediment that exceeds 20% of the design depth. Ditch cleaned/flushed of all sediment and debris so that it matches design. Noxious weeds Any noxious or nuisance vegetation which may constitute a hazard to City personnel or the public. Noxious and nuisance vegetation removed according to applicable regulations. No danger of noxious vegetation where City personnel or the public might normally be. Contaminants and pollution Any evidence of contaminants or pollution such as oil, gasoline, concrete slurries or paint. Materials removed and disposed of according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Excessive vegetation growth Vegetation that reduces free movement of water through ditches. Water flows freely through ditches. Erosion damage to slopes Any erosion observed on a ditch slope. Slopes are not eroding. Rock lining out of place or missing (If applicable) One layer or less of rock exists above native soil area 5 square feet or more, any exposed native soil. Replace rocks to design standards. APPENDIX A MAINTENANCE REQUIREMENTS FOR STORMWATER FACILITIES AND ON-SITE BMPS 12/12/2016 2017 City of Renton Surface Water Design Manual A-38 NO. 26 – GRAVEL FILLED INFILTRATION TRENCH BMP MAINTENANCE COMPONENT DEFECT OR PROBLEM CONDITIONS WHEN MAINTENANCE IS NEEDED RESULTS EXPECTED WHEN MAINTENANCE IS PERFORMED Preventive Blocking, obstructions Debris or trash limiting flow to infiltration trench. Infiltration trench able to receive full flow prior to and during wet season. Site Trash and debris Trash or debris that could end up in the infiltration trench is evident. No trash or debris that could get into the infiltration trench can be found. Pipes Plugged inlet The entrance to the pipe is restricted due to sediment, trash, or debris. The entrance to the pipe is not restricted. Vegetation/root growth in pipes Vegetation/roots that reduce free movement of water through pipes. Water flows freely through pipes. Plugged pipes Sediment or other material prevents free flow of water through the pipe. Water flows freely through pipes. Broken pipe or joint leaks Damage to the pipe or pipe joints allowing water to seep out. Pipe does not allow water to exit other than at the outlet to the trench. Structure Flow not reaching trench Flows are not getting into the trench as designed. Water enters and exits trench as designed. Cleanout/inspection access does not allow cleaning or inspection of trench The cleanout/inspection access is not available. Cleanout/inspection access is available. Filter Media Plugged filter media Filter media plugged. Flow through filter media is normal. APPENDIX A MAINTENANCE REQUIREMENTS FOR STORMWATER FACILITIES AND ON-SITE BMPS 2017 City of Renton Surface Water Design Manual 12/12/2016 A-47 NO. 38 – SOIL AMENDMENT BMP MAINTENANCE COMPONENT DEFECT OR PROBLEM CONDITIONS WHEN MAINTENANCE IS NEEDED RESULTS EXPECTED WHEN MAINTENANCE IS PERFORMED Soil Media Unhealthy vegetation Vegetation not fully covering ground surface or vegetation health is poor. Yellowing: possible Nitrogen (N) deficiency. Poor growth: possible Phosphorous (P) deficiency. Poor flowering, spotting or curled leaves, or weak roots or stems: possible Potassium (K) deficiency. Plants are healthy and appropriate for site conditions Inadequate soil nutrients and structure In the fall, return leaf fall and shredded woody materials from the landscape to the site when possible Soil providing plant nutrients and structure Excessive vegetation growth Grass becomes excessively tall (greater than 10 inches); nuisance weeds and other vegetation start to take over. Healthy turf- “grasscycle” (mulch-mow or leave the clippings) to build turf health Weeds Preventive maintenance Avoid use of pesticides (bug and weed killers), like “weed & feed,” which damage the soil Fertilizer needed Where fertilization is needed (mainly turf and annual flower beds), a moderate fertilization program should be used which relies on compost, natural fertilizers or slow-release synthetic balanced fertilizers Integrated Pest Management (IPM) protocols for fertilization followed Bare spots Bare spots on soil No bare spots, area covered with vegetation or mulch mixed into the underlying soil. Compaction Poor infiltration due to soil compaction • To remediate compaction, aerate soil, till to at least 8-inch depth, or further amend soil with compost and re-till • If areas are turf, aerate compacted areas and top dress them with 1/4 to 1/2 inch of compost to renovate them • If drainage is still slow, consider investigating alternative causes (e.g., high wet season groundwater levels, low permeability soils) • Also consider site use and protection from compacting activities No soil compaction Poor infiltration Soils become waterlogged, do not appear to be infiltrating. Facility infiltrating properly Erosion/Scouring Erosion Areas of potential erosion are visible Causes of erosion (e.g., concentrate flow entering area, channelization of runoff) identified and damaged area stabilized (regrade, rock, vegetation, erosion control matting).For deep channels or cuts (over 3 inches in ponding depth), temporary erosion control measures in place until permanent repairs can be made Grass/Vegetation Unhealthy vegetation Less than 75% of planted vegetation is healthy with a generally good appearance. Healthy vegetation. Unhealthy plants removed/replaced. Appropriate vegetation planted in terms of exposure, soil and soil moisture. Noxious Weeds Noxious weeds Listed noxious vegetation is present (refer to current County noxious weed list). No noxious weeds present. APPENDIX A MAINTENANCE REQUIREMENTS FOR STORMWATER FACILITIES AND ON-SITE BMPS 2017 City of Renton Surface Water Design Manual 12/12/2016 A-49 NO. 41 – COMPOST AMENDED VEGETATED FILTER STRIP (CAVFS) MAINTENANCE COMPONENT DEFECT OR PROBLEM CONDITION WHEN MAINTENANCE IS NEEDED RESULTS EXPECTED WHEN MAINTENANCE IS PERFORMED General Sediment accumulation on grass Sediment depth exceeds 2 inches. Remove sediment deposits. Relevel so slope is even and flows pass evenly through strip. Excessive vegetation growth Grass becomes excessively tall (greater than 10 inches); nuisance weeds and other vegetation start to take over. Mow grass and control nuisance vegetation so that flow is not impeded. Grass should be mowed to a height of 6 inches. Trash and debris Trash and debris have accumulated on the vegetated filter strip. Remove trash and debris from filter. Erosion/scouring Areas have eroded or scoured due to flow channelization or high flows. For ruts or bare areas less than 12 inches wide, repair the damaged area by filling with a 50/50 mixture of crushed gravel and compost. The grass will creep in over the rock in time. If bare areas are large, generally greater than 12 inches wide, the vegetated filter strip should be regraded and reseeded. For smaller bare areas, overseed when bare spots are evident. Flow spreader uneven or clogged Flow spreader is uneven or clogged so that flows are not uniformly distributed over entire filter width. Level the spreader and clean so that flows are spread evenly over entire filter width APPENDIX A MAINTENANCE REQUIREMENTS FOR STORMWATER FACILITIES AND ON-SITE BMPS 12/12/2016 2017 City of Renton Surface Water Design Manual A-52 (This page intentionally left blank.) Appendix A Fair, Equitable, and Understandable Property Valuations You're in: Assessor >> Look up Property Info >> eReal Property Department ofAssessments 500 FourthAvenue,Suite ADM-AS-0708,Seattle, WA98104 Office Hours:Mon - Fri 8:30 a.m. to4:30 p.m. TEL: 206-296-7300FAX: 206-296-5107TTY: 206-296-7888 Send usmail ADVERTISEMENT New SearchProperty Tax BillMap This PropertyGlossary of Terms Area Report Print Property Detail PARCEL DATA Parcel 032305-9245 Name TUSCANY CONSTRUCTIONLLC Site Address 4709 NE 24TH ST 98059 Residential Area 085-001 (SE AppraisalDistrict) Property Name Jurisdiction RENTON Levy Code 2105 Property Type R Plat Block / Building Number Plat Lot / Unit Number Quarter-Section-Township-Range NW-3 -23-5 Legal Description LOT 1 LESS RD DEED 200602113000406 OF KC SP 977031 REC 7803140815 SD SP DAF BEG NXN ELY LNNEWCASTLE RD & NLY LN OF SE 1/4 OF NW 1/4 TH ELY ALG SD NLY LN 364.00 FT TH SLY PLW ELY LN SD RD300.00 FT TH WLY PLW SD NLY LN 364.00 FT TO ELY MGN SD RD TH NLY ALG SD ELY MGN 300.00 FT TO POB PLat Block: Plat Lot: LAND DATA Highest & Best Use As If Vacant SINGLE FAMILY Highest & Best Use AsImproved PRESENT USE Present Use Mobile Home Land SqFt 25,283 Acres 0.58 Percentage Unusable Unbuildable NO Restrictive Size Shape NO Zoning R-4 Water WATER DISTRICT Sewer/Septic PRIVATE Road Access PUBLIC Parking Street Surface PAVED Views Waterfront Rainier Territorial Olympics Cascades Seattle Skyline Puget Sound Lake Washington Lake Sammamish Lake/River/Creek Other View Waterfront Location Waterfront Footage 0 Lot Depth Factor 0 Waterfront Bank Tide/Shore Waterfront Restricted Access Waterfront Access Rights NO Poor Quality NO Proximity Influence NO Designations Nuisances Historic Site Current Use (none) Nbr Bldg Sites Adjacent to Golf Fairway NO Adjacent to Greenbelt NO Other Designation NO Deed Restrictions NO Development Rights Purchased NO Easements NO Native Growth ProtectionEasement NO DNR Lease NO Topography Traffic Noise MODERATE Airport Noise Power Lines NO Other Nuisances NO Problems Water Problems NO Transportation Concurrency NO Other Problems NO Environmental Environmental NO BUILDING Accessory Of Building Number: AccessoryType Picture Description SqFt Grade EffYear %Value DateValued MISC IMP Shed 200 1000 5/23/2016 Real 1988 Barrington Cond 52/28 Double-Wide 1456 Average ADVERTISEMENT ReferenceLinks: King County Tax Links Property Tax Advisor Washington StateDepartment ofRevenue (Externallink) Washington StateBoard of TaxAppeals (External link) Board ofAppeals/Equalization Districts Report iMap Recorder's Office Scanned images ofsurveys and othermap documents Notice mailing date:07/05/2018 Search Kingcounty.gov Home How do I... 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Residents Do more online Trip Planner Get help Contact us TAX ROLL HISTORY Account Valued Year Tax Year Omit Year Levy Code Appraised LandValue ($) Appraised ImpsValue ($) Appraised TotalValue ($) New Dollars($) TaxableLand Value($) TaxableImps Value($) TaxableTotal Value($) Tax ValueReason 032305924501 2018 2019 2105 257,000 35,000 292,000 0 257,000 35,000 292,000 032305924501 2017 2018 2105 234,000 32,000 266,000 0 234,000 32,000 266,000 032305924501 2016 2017 2105 206,000 28,000 234,000 0 206,000 28,000 234,000 032305924501 2015 2016 2105 181,000 40,000 221,000 0 181,000 40,000 221,000 032305924501 2014 2015 2105 170,000 39,000 209,000 0 170,000 39,000 209,000 032305924501 2013 2014 2105 140,000 22,000 162,000 0 140,000 22,000 162,000 032305924501 2012 2013 2105 140,000 23,000 163,000 0 140,000 23,000 163,000 032305924501 2011 2012 2105 146,000 20,000 166,000 0 146,000 20,000 166,000 032305924501 2010 2011 2105 163,000 26,000 189,000 0 163,000 26,000 189,000 032305924501 2009 2010 2105 189,000 15,000 204,000 0 189,000 15,000 204,000 032305924501 2008 2009 2105 215,000 44,000 259,000 0 215,000 44,000 259,000 032305924501 2007 2008 4155 196,000 41,000 237,000 0 196,000 41,000 237,000 032305924501 2006 2007 4155 171,000 38,000 209,000 0 171,000 38,000 209,000 032305924501 2005 2006 4155 149,000 35,000 184,000 0 149,000 35,000 184,000 032305924501 2004 2005 4155 140,000 0 140,000 0 140,000 0 140,000 032305924501 2003 2004 4155 135,000 0 135,000 0 135,000 0 135,000 032305924501 2002 2003 4155 130,000 0 130,000 0 130,000 0 130,000 032305924501 2001 2002 4155 82,000 0 82,000 0 82,000 0 82,000 032305924501 2000 2001 4155 75,000 0 75,000 0 75,000 0 75,000 032305924501 1999 2000 4155 66,000 0 66,000 0 66,000 0 66,000 032305924501 1998 1999 4155 60,000 0 60,000 0 60,000 0 60,000 032305924501 1997 1998 4155 0 0 0 0 55,000 0 55,000 032305924501 1996 1997 4155 0 0 0 0 55,000 0 55,000 032305924501 1994 1995 4155 0 0 0 0 60,000 0 60,000 032305924501 1992 1993 4155 0 0 0 0 38,600 0 38,600 032305924501 1990 1991 4155 0 0 0 0 36,400 0 36,400 032305924501 1988 1989 4155 0 0 0 0 24,300 0 24,300 032305924501 1986 1987 4155 0 0 0 0 23,400 0 23,400 032305924501 1984 1985 4155 0 0 0 0 20,000 0 20,000 032305924501 1982 1983 4155 0 0 0 0 20,000 0 20,000 SALES HISTORY ExciseNumber RecordingNumber DocumentDate Sale Price Seller Name Buyer Name Instrument Sale Reason 2853950 20170317001143 3/15/2017 $262,000.00 WELCH RICHARD TUSCANY CONSTRUCTIONLLC Statutory WarrantyDeed None 2186090 20060213000406 9/26/2005 $0.00 WELCH RICHARDJ+WELCH JODI M KING COUNTY WarrantyDeed Other 1930803 20021230001231 12/24/2002 $0.00 JAMESAMBER+MCDONELLAUTUMN WELCHRICHARD+JODIE Quit ClaimDeed None 1857192 20011213002468 12/6/2001 $0.00 DAVIS JAMESE+LORRAINE M MCDOWELL AMBERM+MCDOWELL AUTUMN L Quit ClaimDeed Executor - toadministrative guardian 1449222 199509260555 9/21/1995 $0.00 MCDOWELL AMBERMARIE DAVIS JAMESE+LORRAINE M Quit ClaimDeed PartialInterest (loveand affection,gift) REVIEW HISTORY PERMIT HISTORY HOME IMPROVEMENT EXEMPTION New SearchProperty Tax BillMap This PropertyGlossary of TermsArea ReportPrint Property Detail ADVERTISEMENT Updated: March 17, 2016  Share  Tweet  Email Businesses Job seekers Volunteers King County employees Property tax information & payment Jail inmate look up Parcel viewer or iMap Public records More online tools... 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View King County social media © King County, WA 2018 Privacy Accessibility Terms of use Information for...Do more online Get help Lake Desire Shady Lake (Mud Lake) Panther Lake Lake Youngs Lake Washington B l ack Ri v e r Gr ee n Ri ver Ce darRi v erUV900 UV167 UV515 UV169 UV900 UV169 UV167BN IncBN IncBBNNIInnccSSEE RReennttoonn IIssssaaqquuaahh RR dd RReennttoonnMMaapplleeVVaalllleeyyRRdd MMaapplleeVVaalllleeyyHHwwyy 110088tthhAAvveeSSEESSWW SSuunnsseettBBllvvdd RRaaii nnii eerrAAvveeNNNE 3rd S t NE 3rd S t SW 43rd StSW 43rd St SSEE CC aarrrrRR dd NE 4th StNE 4th St SSEERReennttoonn MMaappllee VVaalllleeyy RRddLLooggaannAAvveeNN SR 515SR 515PPaarrkkAAvveeNNOOaakkeessddaalleeAAvveeSSWWSSuunnsseettBBllvvddNNEE DDuuvvaallllAAvveeNNEEI-405 FWYI-405 FWY II--440055FFWWYYSR 167SR 1671144 00tthh WWaayy SS EENNEE2277tthh SStt 115566tthhAAvveeSSEEUUnniioonnAAvveeNNEE111166tthhAAvveeSSEESW 7th StSW 7th St N 8th StN 8th St PP uuggeettDD rrSSEE RR ee nnttoo nnAAvvee SS SSWW 2277tthh SStt BBeennssoonnRRddSSWWiilllliiaammssAAvveeSSMMoonnrrooeeAAvveeNNEESE 128th StSE 128th St II nntt eerr uurr bbaannAA vvee SS HHooqquuiiaammAAvveeNNEE8844tthhAAvveeSSSSEEPPeett rr oovvii tt sskkyyRRddEEVVaalllleeyyHHwwyySE 192nd StSE 192nd St SE 60th StSE 60th St TTaallbboottRRddSSRRee nn tt oo nn AAvveeSS116644tthhAAvveeSSEESE 208th StSE 208th St SE 72nd StSE 72nd St RR aaiinniieerr AAvvee SS 111166tthhAAvveeSSEES 128th StS 128th St NNeewwccaassttllee WWaayy SS 221122tthh SStt SS118800tthh SStt CCooaall CCrreeeekkPPkkwwyySSEESW 41st StSW 41st St 114400tthhAAvveeSSEE112288tthhAAvveeSSEE6688tthhAAvveeSSSSEE 116688tthh SStt NE 12th StNE 12th St BBeeaacc oonn AAvv ee SSFFoorreesstt DDrr SSEE SSEE 116644tthh SStt 114488tthhAAvveeSSEESSEE MMaayy VVaalllleeyyRRdd SS EE JJoonneess RRdd SS EE 22 00 44 tthh WW aayySW 34th StSW 34th St SE 144th StSE 144th St 114488tthhAAvveeSSEE115544tthhPPllSSEELL aa kk ee WWaa sshhii nnggtt oonnBBll vvddNNEEddmmoonnddssAAvveeNNEEAAbbeerrddeeeennAAvveeNNEEEEMM eerrcceerrWWaayyWWeessttVVaalllleeyyHHwwyyEast Valley RdEast Valley Rd,§-405 ,§-405 ,§-405 µ0 1 2 Miles Flow Control Application Map Reference 1-A Date: 01/09/2014 Flow Control Standards Peak Rate Flow Control Standard (Existing Site Conditions) Flow Control Duration Standard (Existing Site Conditions) Flow Control Duration Standard (Forested Conditions) Flood Problem Flow Unincorporated King County Flow Control Standards Renton City Limits Potential Annexation Area PROJECT SITE Appendix B k k k k k k k k k k k k k k k k k k k k k k k k k k k kk k k k k k k k k k k k k k k k k k k k HoquiamAveNEE Valley Hwy84thAveSNEParkDr SW 7th St SE 128th St SE 192nd StLind Ave SWMainAveSS 132nd St Factory PlN Tal bot Rd SN 3rd St RainierAveS 164thAveSETukwilaPkwy SPugetDr NE 4th St S 3rd St S 129th S t68th Ave S SWSunsetBlvd SW 16th St 116thAveSEN 4th St In t e r u r b a n A v e S WilliamsAveNBronsonWa y N NE7thSt 124thAveSES 7th St SERento n IssaquahRd Rai ni er AveNNewcastle Way CoalCre ek PkwySESW 41st St Ta y l o r P l NW NESunsetBlvdWellsAveNUnionAveNENE 3rd St Hardie Av eSWS180th St Maple V a l l e y H w y 140thAveSES G ra d y W ayS 2 1 s tSt BensonRdSRento n AveS87thAveS128thAveSE148thAveSESW 43rd St SEC arrRd SE 168thSt Beacon Ave S 68thAveSLoganAveN108thAveSEForestDrSE S2ndSt 141s t AveSERainier AveS156thAveSES E 183rdStBe n s on D r S S124th StS 43rd St Airport Way S W G ra dyW a y SE J o n es RdSunsetBlvdN Puget Dr SESE 204th Way SW 34th StMo n sterRdSW SE 142nd Pl WestValleyHwySSEMayValleyRd SunsetBlvdNS Carr RdHouserWayNNewcastleGolfClubRd S 133rd St Williams AveSWellsAveSEMercerWay154thPlSEDuvallAveNELoganAveSMonroeAveNESunsetBlvdNEEdmondsAveNEStevens AveNWRai ni er AveSTalbotRdSOakesdaleAveSWTaylorAveNW164thAveSERainierAve SWestVall eyHwyWestValleyHwyParkAveN108thAveSE6 6th A v e S WM ercerWayWMercer W ay LakemontBl vdSE132ndAve SELakeWashingtonBlvdNE140thWaySE East Valley Rd68thAveS³City of Renton Sensitive Areas 0 0.5 10.25 Miles Information Technology - GIS mapsupport@rentonwa.govPrinted on: 11/12/2014 Data Sources: City of Renton, King County This document is a graphic representation, not guaranteed to survey accuracy, and is based on the best informationavailable as of the date shown. This map is intended for City display purposes only. Renton City Limits k Education Fire Station K Valley Medical Center Aquifer Protection Zone 1 Zone 1 Modified Zone 2 Coordinate System: NAD 1983 HARN StatePlane Washington North FIPS 4601 FeetProjection: Lambert Conformal ConicDatum: North American 1983 HARN PROJECT SITE RentonKent Newcastle King CountyTukwilaMercer Island Bellevu e Lake Washington Lake Youngs Panther Lake Lake Boren Cedar RiverBlack River May Creek Springbrook Creek Cougar MountainCougar Mountain Coal Creek ParkCoal Creek Park Cedar River Natural ZoneCedar River Natural Zone May Creek ParkMay Creek Park Soos Creek Park and TrailSoos Creek Park and Trail Black River Riparian ForestBlack River Riparian Forest McGarvey Open SpaceMcGarvey Open Space Maplewood Community ParkMaplewood Community Park ValleyValley BensonBenson HighlandsHighlands West HillWest Hill East PlateauEast Plateau SE 192ND STTALBOT RD S140TH AVE SERAI N I E R A V E S EAST VALLEY RDSE 168TH ST RENTON A V E S116TH AVE SENE 12TH STE M ERCER WAY148TH AVE SENE 7TH S T84TH AVE SHOQUIAM AVE NENEWCASTLE WAY W M E RCER WAY S 128TH ST SW 41ST ST PARK AVE N128TH AVE SESE JONES R D E VALLEY HWYSE 72ND ST SE 164TH ST NILE AVE NEN 10TH S T SE 183RD S TUNION AVE NE156TH AVE SEUNION AVE SENE 2ND ST 148TH AVE SESE 164TH STLIND AVE SWUNION AVE NE116TH AVE SESW 7TH ST N 8TH ST EDMONDS AVE NEPUGET DR S E NE 27TH ST 156TH AVE SERENTON AVE S BENSON RD SMONROE AVE NE116TH AVE SENE 4TH ST SR 515 SUNS E T B LV D N E PARK AVE NMAPLE VALLEY HWY SW 43RD ST NE 3RD STLOGAN AVE NSW SU NSET BLVD SW GRADY W A Y N 3RD STRAINIER AVE N 140TH WAY SESR 167108TH AVE SEN 6TH ST S 2ND ST 108TH AVE SESR 515[^405 [^405 Effective FEMA Flood Insurance Rate Map µ Legend Renton City Limits Zone AE, A, AH, AO - Regulatory Zone X - Non Regulatory 0 0.5 10.25 Miles Public Works - Surface Water UtilityPrint Date: 11/05/2012 Data Sources: City of Renton, FEMA FIRM revised May 16, 1995.Cedar River flood hazard area updated with FEMA Cedar RiverLOMR (Case No. 06-10-B569P) approved December 4, 2006. This document is a graphic representation, not guaranteedto survey accuracy, and is based on the best informationavailable as of the date shown. This map is intended forCity display purposes only. PROJECT SITE k k k k k k k k k k k k k k k k k k k k k k k k k k k kk k k k k k k k k k k k k k k k k k k k HoquiamAveNEE Valley Hwy84thAveSNEParkDr SW 7th St SE 128th St SE 192nd StLind Ave SWMainAveSS 132nd St Factory PlN Tal bot Rd SN 3rd St RainierAveS 164thAveSETukwilaPkwy SPugetDr NE 4th St S 3rd St S 129th S t68th Ave S SWSunsetBlvd SW 16th St 116thAveSEN 4th St In t e r u r b a n A v e S WilliamsAveNBronsonWa y N NE7thSt 124thAveSES 7th St SERento n IssaquahRd Rai ni er AveNNewcastle Way CoalCre ek PkwySESW 41st St Ta y l o r P l NW NESunsetBlvdWellsAveNUnionAveNENE 3rd St Hardie Av eSWS180th St Maple V a l l e y H w y 140thAveSES G ra d y W ayS 2 1 s tSt BensonRdSRento n AveS87thAveS128thAveSE148thAveSESW 43rd St SEC arrRd SE 168thSt Beacon Ave S 68thAveSLoganAveN108thAveSEForestDrSE S2ndSt 141s t AveSERainier AveS156thAveSES E 183rdStBe n s on D r S S124th StS 43rd St Airport Way S W G ra dyW a y SE J o n es RdSunsetBlvdN Puget Dr SESE 204th Way SW 34th StMo n sterRdSW SE 142nd Pl WestValleyHwySSEMayValleyRd SunsetBlvdNS Carr RdHouserWayNNewcastleGolfClubRd S 133rd St Williams AveSWellsAveSEMercerWay154thPlSEDuvallAveNELoganAveSMonroeAveNESunsetBlvdNEEdmondsAveNEStevens AveNWRai ni er AveSTalbotRdSOakesdaleAveSWTaylorAveNW164thAveSERainierAve SWestVall eyHwyWestValleyHwyParkAveN108thAveSE6 6th A v e S WM ercerWayWMercer W ay LakemontBl vdSE132ndAve SELakeWashingtonBlvdNE140thWaySE East Valley Rd68thAveS³City of Renton Sensitive Areas 0 0.5 10.25 Miles Information Technology - GIS mapsupport@rentonwa.govPrinted on: 11/12/2014 Data Sources: City of Renton, King County This document is a graphic representation, not guaranteed to survey accuracy, and is based on the best informationavailable as of the date shown. This map is intended for City display purposes only. Renton City Limits k Education Fire Station K Valley Medical Center Coal Mine HazardsSeverity HIGH MODERATE UNCLASSIFIED Coordinate System: NAD 1983 HARN StatePlane Washington North FIPS 4601 FeetProjection: Lambert Conformal ConicDatum: North American 1983 HARN PROJECT SITE k k k k k k k k k k k k k k k k k k k k k k k k k k k kk k k k k k k k k k k k k k k k k k k k HoquiamAveNEE Valley Hwy84thAveSNEParkDr SW 7th St SE 128th St SE 192nd StLind Ave SWMainAveSS 132nd St Factory PlN Tal bot Rd SN 3rd St RainierAveS 164thAveSETukwilaPkwy SPugetDr NE 4th St S 3rd St S 129th S t68th Ave S SWSunsetBlvd SW 16th St 116thAveSEN 4th St In t e r u r b a n A v e S WilliamsAveNBronsonWa y N NE7thSt 124thAveSES 7th St SERento n IssaquahRd Rai ni er AveNNewcastle Way CoalCre ek PkwySESW 41st St Ta y l o r P l NW NESunsetBlvdWellsAveNUnionAveNENE 3rd St Hardie Av eSWS180th St Maple V a l l e y H w y 140thAveSES G ra d y W ayS 2 1 s tSt BensonRdSRento n AveS87thAveS128thAveSE148thAveSESW 43rd St SEC arrRd SE 168thSt Beacon Ave S 68thAveSLoganAveN108thAveSEForestDrSE S2ndSt 141s t AveSERainier AveS156thAveSES E 183rdStBe n s on D r S S124th StS 43rd St Airport Way S W G ra dyW a y SE J o n es RdSunsetBlvdN Puget Dr SESE 204th Way SW 34th StMo n sterRdSW SE 142nd Pl WestValleyHwySSEMayValleyRd SunsetBlvdNS Carr RdHouserWayNNewcastleGolfClubRd S 133rd St Williams AveSWellsAveSEMercerWay154thPlSEDuvallAveNELoganAveSMonroeAveNESunsetBlvdNEEdmondsAveNEStevens AveNWRai ni er AveSTalbotRdSOakesdaleAveSWTaylorAveNW164thAveSERainierAve SWestVall eyHwyWestValleyHwyParkAveN108thAveSE6 6th A v e S WM ercerWayWMercer W ay LakemontBl vdSE132ndAve SELakeWashingtonBlvdNE140thWaySE East Valley Rd68thAveS³City of Renton Sensitive Areas 0 0.5 10.25 Miles Information Technology - GIS mapsupport@rentonwa.govPrinted on: 11/12/2014 Data Sources: City of Renton, King County This document is a graphic representation, not guaranteed to survey accuracy, and is based on the best informationavailable as of the date shown. This map is intended for City display purposes only. Renton City Limits k Education Fire Station K Valley Medical Center Erosion HazardSeverity High Coordinate System: NAD 1983 HARN StatePlane Washington North FIPS 4601 FeetProjection: Lambert Conformal ConicDatum: North American 1983 HARN PROJECT SITE k k k k k k k k k k k k k k k k k k k k k k k k k k k kk k k k k k k k k k k k k k k k k k k k HoquiamAveNEE Valley Hwy84thAveSNEParkDr SW 7th St SE 128th St SE 192nd StLind Ave SWMainAveSS 132nd St Factory PlN Tal bot Rd SN 3rd St RainierAveS 164thAveSETukwilaPkwy SPugetDr NE 4th St S 3rd St S 129th S t68th Ave S SWSunsetBlvd SW 16th St 116thAveSEN 4th St In t e r u r b a n A v e S WilliamsAveNBronsonWa y N NE7thSt 124thAveSES 7th St SERento n IssaquahRd Rai ni er AveNNewcastle Way CoalCre ek PkwySESW 41st St Ta y l o r P l NW NESunsetBlvdWellsAveNUnionAveNENE 3rd St Hardie Av eSWS180th St Maple V a l l e y H w y 140thAveSES G ra d y W ayS 2 1 s tSt BensonRdSRento n AveS87thAveS128thAveSE148thAveSESW 43rd St SEC arrRd SE 168thSt Beacon Ave S 68thAveSLoganAveN108thAveSEForestDrSE S2ndSt 141s t AveSERainier AveS156thAveSES E 183rdStBe n s on D r S S124th StS 43rd St Airport Way S W G ra dyW a y SE J o n es RdSunsetBlvdN Puget Dr SESE 204th Way SW 34th StMo n sterRdSW SE 142nd Pl WestValleyHwySSEMayValleyRd SunsetBlvdNS Carr RdHouserWayNNewcastleGolfClubRd S 133rd St Williams AveSWellsAveSEMercerWay154thPlSEDuvallAveNELoganAveSMonroeAveNESunsetBlvdNEEdmondsAveNEStevens AveNWRai ni er AveSTalbotRdSOakesdaleAveSWTaylorAveNW164thAveSERainierAve SWestVall eyHwyWestValleyHwyParkAveN108thAveSE6 6th A v e S WM ercerWayWMercer W ay LakemontBl vdSE132ndAve SELakeWashingtonBlvdNE140thWaySE East Valley Rd68thAveS³City of Renton Sensitive Areas 0 0.5 10.25 Miles Information Technology - GIS mapsupport@rentonwa.govPrinted on: 11/12/2014 Data Sources: City of Renton, King County This document is a graphic representation, not guaranteed to survey accuracy, and is based on the best informationavailable as of the date shown. This map is intended for City display purposes only. Renton City Limits k Education Fire Station K Valley Medical Center Landslide Hazard Severity Very High High Moderate Unclassified Coordinate System: NAD 1983 HARN StatePlane Washington North FIPS 4601 FeetProjection: Lambert Conformal ConicDatum: North American 1983 HARN PROJECT SITE k k k k k k k k k k k k k k k k k k k k k k k k k k k kk k k k k k k k k k k k k k k k k k k k HoquiamAveNEE Valley Hwy84thAveSNEParkDr SW 7th St SE 128th St SE 192nd StLind Ave SWMainAveSS 132nd St Factory PlN Tal bot Rd SN 3rd St RainierAveS 164thAveSETukwilaPkwy SPugetDr NE 4th St S 3rd St S 129th S t68th Ave S SWSunsetBlvd SW 16th St 116thAveSEN 4th St In t e r u r b a n A v e S WilliamsAveNBronsonWa y N NE7thSt 124thAveSES 7th St SERento n IssaquahRd Rai ni er AveNNewcastle Way CoalCre ek PkwySESW 41st St Ta y l o r P l NW NESunsetBlvdWellsAveNUnionAveNENE 3rd St Hardie Av eSWS180th St Maple V a l l e y H w y 140thAveSES G ra d y W ayS 2 1 s tSt BensonRdSRento n AveS87thAveS128thAveSE148thAveSESW 43rd St SEC arrRd SE 168thSt Beacon Ave S 68thAveSLoganAveN108thAveSEForestDrSE S2ndSt 141s t AveSERainier AveS156thAveSES E 183rdStBe n s on D r S S124th StS 43rd St Airport Way S W G ra dyW a y SE J o n es RdSunsetBlvdN Puget Dr SESE 204th Way SW 34th StMo n sterRdSW SE 142nd Pl WestValleyHwySSEMayValleyRd SunsetBlvdNS Carr RdHouserWayNNewcastleGolfClubRd S 133rd St Williams AveSWellsAveSEMercerWay154thPlSEDuvallAveNELoganAveSMonroeAveNESunsetBlvdNEEdmondsAveNEStevens AveNWRai ni er AveSTalbotRdSOakesdaleAveSWTaylorAveNW164thAveSERainierAve SWestVall eyHwyWestValleyHwyParkAveN108thAveSE6 6th A v e S WM ercerWayWMercer W ay LakemontBl vdSE132ndAve SELakeWashingtonBlvdNE140thWaySE East Valley Rd68thAveS³City of Renton Sensitive Areas 0 0.5 10.25 Miles Information Technology - GIS mapsupport@rentonwa.govPrinted on: 11/12/2014 Data Sources: City of Renton, King County This document is a graphic representation, not guaranteed to survey accuracy, and is based on the best informationavailable as of the date shown. This map is intended for City display purposes only. Renton City Limits k Education Fire Station K Valley Medical Center Steep SlopesPercent Range >15% & <=25% >25% & <=40% >40% & <=90% >90%Coordinate System: NAD 1983 HARN StatePlane Washington North FIPS 4601 FeetProjection: Lambert Conformal ConicDatum: North American 1983 HARN PROJECT SITE King County King County iMap Date: 11/12/2019 Notes: The information included on this map has been compiled by King County staff from a variety of sources and is subject to changewithout notice. King County makes no representations or warranties, express or implied, as to accuracy, completeness, timeliness,or rights to the use of such information. This document is not intended for use as a survey product. King County shall not be liable for any general, special, indirect, incidental, or consequential damages including, but not limited to, lost revenues or lost profitsresulting from the use or misuse of the information contained on this map. Any sale of this map or information on this map isprohibited except by written permission of King County.± 1998-0427 Date Closed 8/5/98 1982-0030 Date Closed 12/29/82 Project Site Appendix C ————————————————————————————————— MGS FLOOD PROJECT REPORT Program Version: MGSFlood 4.52 Program License Number: 200210008 Project Simulation Performed on: 12/14/2020 11:41 AM Report Generation Date: 12/14/2020 11:42 AM ————————————————————————————————— Input File Name: 18265.fld Project Name: NE 24th St Short Plat Analysis Title: Comments: ———————————————— PRECIPITATION INPUT ———————————————— Computational Time Step (Minutes): 15 Extended Precipitation Time Series Selected Climatic Region Number: 17 Full Period of Record Available used for Routing Precipitation Station : 96004805 Puget East 48 in_5min 10/01/1939-10/01/2097 Evaporation Station : 961048 Puget East 48 in MAP Evaporation Scale Factor : 0.750 HSPF Parameter Region Number: 1 HSPF Parameter Region Name : USGS Default ********** Default HSPF Parameters Used (Not Modified by User) *************** ********************** WATERSHED DEFINITION *********************** Predevelopment/Post Development Tributary Area Summary Predeveloped Post Developed Total Subbasin Area (acres) 0.570 0.570 Area of Links that Include Precip/Evap (acres) 0.000 0.000 Total (acres) 0.570 0.570 ----------------------SCENARIO: PREDEVELOPED Number of Subbasins: 1 ---------- Subbasin : Predeveloped ---------- -------Area (Acres) -------- Till Forest 0.500 Outwash Forest 0.050 Impervious 0.020 ---------------------------------------------- Subbasin Total 0.570 ----------------------SCENARIO: POSTDEVELOPED Number of Subbasins: 1 ---------- Subbasin : Developed ---------- -------Area (Acres) -------- Till Grass 0.230 Outwash Forest 0.120 Outwash Grass 0.050 Impervious 0.170 ---------------------------------------------- Subbasin Total 0.570 ************************* LINK DATA ******************************* ----------------------SCENARIO: PREDEVELOPED Number of Links: 0 ************************* LINK DATA ******************************* ----------------------SCENARIO: POSTDEVELOPED Number of Links: 1 ------------------------------------------ Link Name: Det Vault Link Type: Structure Downstream Link: None Prismatic Pond Option Used Pond Floor Elevation (ft) : 415.75 Riser Crest Elevation (ft) : 420.96 Max Pond Elevation (ft) : 422.00 Storage Depth (ft) : 5.21 Pond Bottom Length (ft) : 63.6 Pond Bottom Width (ft) : 12.0 Pond Side Slopes (ft/ft) : L1= 0.00 L2= 0.00 W1= 0.00 W2= 0.00 Bottom Area (sq-ft) : 763. Area at Riser Crest El (sq-ft) : 763. (acres) : 0.018 Volume at Riser Crest (cu-ft) : 3,975. (ac-ft) : 0.091 Area at Max Elevation (sq-ft) : 763. (acres) : 0.018 Vol at Max Elevation (cu-ft) : 4,768. (ac-ft) : 0.109 Hydraulic Conductivity (in/hr) : 0.00 Massmann Regression Used to Estimate Hydralic Gradient Depth to Water Table (ft) : 100.00 Bio-Fouling Potential : Low Maintenance : Average or Better Riser Geometry Riser Structure Type : Circular Riser Diameter (in) : 8.00 Common Length (ft) : 0.000 Riser Crest Elevation : 420.96 ft Hydraulic Structure Geometry Number of Devices: 2 ---Device Number 1 --- Device Type : Circular Orifice Control Elevation (ft) : 415.75 Diameter (in) : 0.50 Orientation : Horizontal Elbow : No ---Device Number 2 --- Device Type : Circular Orifice Control Elevation (ft) : 418.50 Diameter (in) : 0.75 Orientation : Horizontal Elbow : Yes **********************FLOOD FREQUENCY AND DURATION STATISTICS******************* ----------------------SCENARIO: PREDEVELOPED Number of Subbasins: 1 Number of Links: 0 ----------------------SCENARIO: POSTDEVELOPED Number of Subbasins: 1 Number of Links: 1 ********** Link: Det Vault ********** Link WSEL Stats WSEL Frequency Data(ft) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) WSEL Peak (ft) ====================================== 1.05-Year 416.905 1.11-Year 417.047 1.25-Year 417.303 2.00-Year 417.930 3.33-Year 418.378 5-Year 418.696 10-Year 419.124 25-Year 419.788 50-Year 420.034 100-Year 420.153 ***********Groundwater Recharge Summary ************* Recharge is computed as input to Perlnd Groundwater Plus Infiltration in Structures Total Predeveloped Recharge During Simulation Model Element Recharge Amount (ac-ft) ----------------------------------------------------------------------------------------------- Subbasin: Predeveloped 120.727 _____________________________________ Total: 120.727 Total Post Developed Recharge During Simulation Model Element Recharge Amount (ac-ft) ----------------------------------------------------------------------------------------------- Subbasin: Developed 95.588 Link: Det Vault 0.000 _____________________________________ Total: 95.588 Total Predevelopment Recharge is Greater than Post Developed Average Recharge Per Year, (Number of Years= 158) Predeveloped: 0.764 ac-ft/year, Post Developed: 0.605 ac-ft/year ***********Water Quality Facility Data ************* ----------------------SCENARIO: PREDEVELOPED Number of Links: 0 ----------------------SCENARIO: POSTDEVELOPED Number of Links: 1 ********** Link: Det Vault ********** Basic Wet Pond Volume (91% Exceedance): 1243. cu-ft Computed Large Wet Pond Volume, 1.5*Basic Volume: 1865. cu-ft Infiltration/Filtration Statistics-------------------- Inflow Volume (ac-ft): 161.81 Inflow Volume Including PPT-Evap (ac-ft): 161.81 Total Runoff Infiltrated (ac-ft): 0.00, 0.00% Total Runoff Filtered (ac-ft): 0.00, 0.00% Primary Outflow To Downstream System (ac-ft): 161.80 Secondary Outflow To Downstream System (ac-ft): 0.00 Percent Treated (Infiltrated+Filtered)/Total Volume: 0.00% ***********Compliance Point Results ************* Scenario Predeveloped Compliance Subbasin: Predeveloped Scenario Postdeveloped Compliance Link: Det Vault *** Point of Compliance Flow Frequency Data *** Recurrence Interval Computed Using Gringorten Plotting Position Predevelopment Runoff Postdevelopment Runoff Tr (Years) Discharge (cfs) Tr (Years) Discharge (cfs) ---------------------------------------------------------------------------------------------------------------------- 2-Year 2.015E-02 2-Year 9.850E-03 5-Year 3.123E-02 5-Year 1.773E-02 10-Year 4.066E-02 10-Year 2.352E-02 25-Year 5.589E-02 25-Year 2.958E-02 50-Year 6.935E-02 50-Year 3.146E-02 100-Year 7.440E-02 100-Year 3.233E-02 200-Year 0.115 200-Year 3.288E-02 500-Year 0.170 500-Year 3.359E-02 ** Record too Short to Compute Peak Discharge for These Recurrence Intervals **** Flow Duration Performance **** Excursion at Predeveloped 50%Q2 (Must be Less Than or Equal to 0%): -50.9% PASS Maximum Excursion from 50%Q2 to Q2 (Must be Less Than or Equal to 0%): -32.5% PASS Maximum Excursion from Q2 to Q50 (Must be less than 10%): -31.1% PASS Percent Excursion from Q2 to Q50 (Must be less than 50%): 0.0% PASS ------------------------------------------------------------------------------------------------- MEETS ALL FLOW DURATION DESIGN CRITERIA: PASS ------------------------------------------------------------------------------------------------- Appendix D Cobalt Geosciences P.O. Box 82243 Kenmore, Washington 98028 (206) 331-1097 March 28, 2017 Updated April 25, 2018 Mr. Bob Wenzl C/O Mr. Darrell Offe, PE 13932 SE 159th Place Renton, Washington RE: Stormwater Feasibility Evaluation Proposed Single Family Residences 4709 NE 24th Street Renton, Washington Dear Mr. Offe, In accordance with your authorization, Cobalt Geosciences, LLC has prepared this letter to discuss the results of our stormwater feasibility evaluation at the referenced site. Site and Project Description The site is located at 2407 NE 24th Street in Renton, Washington. The site consists of one rectangular shaped parcel with a total area of about 25,283 square feet. Currently, the east portion of the site is developed with a single-family residence and driveway. The remainder of the site is landscaped with sparse trees, grasses, and shrubs/bushes. Overall the site slopes gently downward toward the west. Slopes within the site are generally less than 10 percent and the overall topographic relief is less than 10 feet. The property is bordered to the north by NE 24th Street, to the west by Duvall Avenue NE, and to the south and east by single family residences. The project consists of removing the existing structures and developing the site with two single family residences. Stormwater management may consist of infiltration, dispersion, rain gardens, or tightlines into city infrastructure. Area Geology The Geologic Map of King County, indicates that the site is underlain by Vashon Glacial Till. Vashon Glacial Till is typically characterized by an unsorted, non-stratified mixture of clay, silt, sand, gravel, cobbles and boulders in variable quantities. These materials are typically dense and relatively impermeable. The poor sorting reflects the mixing of the materials as these sediments were overridden and incorporated by the glacial ice. March 28, 2017 Updated April 25, 2018 Page 2 of 3 Stormwater Feasibility Evaluation Soil & Groundwater Conditions As part of our evaluation, we excavated and sampled two test pits up to 8 feet below grade in accessible areas of the property. Figure 1 shows the general location of the explorations. Exploration logs are attached at the end of this letter report. Test Pit TP-1 encountered approximately 6 inches of topsoil and grass underlain by approximately 2 feet of loose to medium dense, silty-fine to medium grained sand with gravel (Fill). This layer was underlain by approximately 3.5 feet of medium dense, fine to coarse grained gravel with sand and silt (Recessional Outwash). This layer was underlain by stiff silt with fine grained sand (Recessional Outwash – Lacustrine), which continued to the termination depth of the test pit. Test Pit TP-2 encountered approximately 6 inches of topsoil and grass underlain by approximately 3.5 feet of loose, silty-sand to sandy silt (Fill). This layer was underlain by medium stiff to stiff, silt with fine grained sand (Recessional Outwash – Lacustrine), which continued to the termination depth of the test pit. Groundwater was encountered in TP-1 at 5.5 feet below grade and in TP-2 at approximately 6 feet below grade. Groundwater appears to be perched on/within recessional deposits. Stormwater Management Feasibility Based on the explorations, infiltration appears to be feasible in the area of TP-1. Infiltration is not feasible in the very fine-grained silt deposits that underlie the fill and local areas of poorly graded gravel. We conducted a falling head infiltration test in TP-1 at 4 feet below grade. The short term rate was observed to be greater than 8 inches per hour. Due to the presence of groundwater and impermeable soils, we recommend limiting infiltration system depth to 2 to 4 feet below existing grade. However, the geotechnical engineer should be on site during system placement to verify that the gravelly outwash soils are present at system locations, and to verify at least 1 foot clearance above groundwater. The soils in TP-1 between 2.5 and 6 feet below grade should be considered to be “Medium Sand” per the King County Surface Water Design Manual. While the soils are very gravelly, they have areas of silt which will decrease the rate of infiltration. Therefore, each infiltration trench should have a length of 30 feet for each 1,000 square feet of impervious surface area. Infiltration does not appear feasible in the east lot. Limited dispersion or other shallow systems should be considered. Additional explorations could be performed in order to delineate areas of outwash gravels and sands that may be present within the property. Closure The information presented herein is based upon professional interpretation utilizing standard practices and a degree of conservatism deemed proper for this project. We emphasize that this report is valid for this project as outlined above and for the current site conditions and should not be used for any other site. March 28, 2017 Updated April 25, 2018 Page 3 of 3 Stormwater Feasibility Evaluation Sincerely, Cobalt Geosciences, LLC Phil Haberman, P.G., P.E.G. Principal Engineering Geologist PH/sc SITE PLAN FIGURE 1 P.O. Box 82243 Kenmore, WA 98028 (206) 331-1097 cobaltgeo@gmail.comCobalt Geosciences N Stormwater Feasibility Evaluation 4709 NE 24th Street Renton, Washington TP-1 TP-1 TP-2 TEST PIT LOGS P.O. Box 82243 Kenmore, WA 98028 (206) 331-1097 cobaltgeo@gmail.comCobalt Geosciences Test Pit TP-1 0-0.5’ Vegetation/Topsoil 0.5-2.5’ Silty Sand (SM) Loose to medium dense, silty-fine to medium grained sand trace gravel, mottled yellowish brown to grayish brown, moist. (Fill) 2.5-6’ Gravel with Sand and Silt (GP) Medium dense, fine to coarse gravel with sand and silt, yellowish brown, moist to wet (Recessional Outwash) 6-8’ Silt with Sand (ML) Stiff, silt with fine grained sand trace gravel, mottled tan to yellowish brown, moist. (Lacustrine Deposits) End of Test Pit 8’ Groundwater at 5.5 No Caving SM Recessional Outwash Topsoil/Vegetation 0.5’ Test Pit TP-2 0-0.5’ Vegetation/Topsoil 0.5-4’ Silty Sand with Gravel (SM) Loose to medium dense, silty-fine to medium grained sand with gravel, mottled yellowish brown to grayish brown, moist. (Fill) 4-8’ Silt with Sand (ML)Medium stiff to stiff, silt with fine grained sand trace gravel, mottled yellowish brown to grayish brown, moist to wet. (Lacustrine Deposits) End of Test Pit 8’ Groundwater at 6’ No Caving ML SM Fill Fill Lacustrine Deposits 0.5’ 4’ USCS Graphic USCS Graphic 4709 NE 24th Street Renton, Washington 2.5’ Topsoil/Vegetation LLC GP ML Lacustrine Deposits 6’