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Home My WebLink AboutTIR-3919FINAL R-3919LUA-16000078 PR-16000242 U-16006039 IN COMPIANCE WITH CITY OF RENTON STANDARDS DEVELOPMENT ENGINEERING Ann Fowler 02/14/2018 SURFACE WATER UTILITY rstraka 02/20/2018 Table of Contents · Section 1: Project Overview · Section 2: Conditions and Requirements Summary · Section 3: Offsite Analysis · Section 4: Flow Control and Water Quality Analysis and Design · Section 5: Conveyance System Analysis and Design · Section 6: Special Reports and Studies · Section 7: Other Permits · Section 8: CSWPPP Analysis and Design · Section 9: Bond Quantities, Facility Summaries, and Declaration of Covenant · Section 10: Operations and Maintenance Manual TIR Section 1: Project Overview This proposed project is to create 15 single family lots from two existing King County tax parcels (#142305-9070 & 9064) located in the easterly portion of the Renton Highlands. The property addresses are: 6201 and 6207 NE 4th Street. The project consists of two parcels having 210,595 square feet (4.83 acres). The property has three existing residences located on it: two of which will be removed and the third (6201 NE 4th Street) will be retained after development. The current property has multi uses: the northerly area of the westerly parcel is used to grow Christmas trees, the southerly and mid portion of the project is fenced for agricultural use, the three residences having lawn and landscaping for single family use. A new access road will be provided along the westerly side with the extension of NE 3rd Court onto the property. Access to the developed project will be from this access point. An emergency access point will be provided to NE 4th Street. This project will be reviewed for drainage under the 2009 King County Surface Water Drainage Manual and the City of Renton Amendments. The project will install a storm water wet vault in the southwest corner to provide storm water detention and water quality. The storm water facility will discharge at the natural discharge point (SW corner of property). The property is served by King County Water District #90 for water service. The property is flat with very gentle grade from the northeast corner to the southwest corner, at the natural discharge point. The soils were found to be Alderwood Series (Glacial Till) soils. There is a high ground water table on the property due to the hard-compact soils just below the grass. These soils allow for minimal infiltration of runoff. The proposed developed stormwater mitigation will be to provide a storm water facility to treat developed runoff flows and water quality treatment. Figure #1 - TIR Worksheet City of Renton TECHNICAL INFORMATION REPORT (TIR) WORKSHEET Part 1 PROJECT OWNER AND PROJECT ENGINEER Part 2 PROJECT LOCATION AND DESCRIPTION Project Owner: Kendall Homes, Inc. Address: 612 South Lucile Street Seattle, WA 98108 Phone: Project Engineer: Darrell Offe, P.E. Company: Offe Engineers, PLLC Address/Phone: 13932 SE 159th Place Renton, WA 98058 (425) 260-3412 Project Name: Renton 14 Plat Location Township: 23 North Range: 5 East Section: 14 Part 3 TYPE OF PERMIT APPLICATION Part 4 OTHER REVIEWS AND PERMITS Subdivision X Subdivision • Grading • Commercial • Other _______________________ _______________________________ • DFW HPA • Shoreline Management • COE 404 Rockery • DOE Dam Safety Structural Vaults • FEMA Floodplain • Other • COE Wetlands Part 5 SITE COMMUNITY AND DRAINAGE BASIN Community Renton East Highlands Drainage Basin Maplewood Creek/ Lower Cedar River / Lake Washington Part 6 SITE CHARACTERISTICS • River _________________________________ • Stream • Critical Stream Reach • Depressions/Swales • Lake _____________________________ • Steep Slopes ______________________ • Floodplain ______________________ • Seeps/Springs • High Groundwater Table • Groundwater Recharge • Other __________________________ Part 7 SOILS Soil Type _________________ Qvt _________________ _________________ Slopes _________________ 5 – 10% _________________ _________________ Erosion Potential _________________ minor _________________ _________________ Erosive Velocities _________________ _________________ _________________ _________________ • Additional Sheets Attached Part 8 DEVELOPMENT LIMITATIONS REFERENCE • Ch. 4 – Downstream Analysis______ • ______________________________ • ______________________________ • ______________________________ • ______________________________ • ______________________________ • Additional Sheets Attached LIMITATION/SITE CONSTRAINT _________________________________ _______________________________________ _______________________________________ _______________________________________ _______________________________________ Part 9 ESC REQUIREMENTS MINIMUM ESC REQUIREMENTS DURING CONSTRUCTION X Sedimentation Facilities X Stabilized Construction Entrance X Perimeter Runoff Control X Clearing and Grading Restrictions X Cover Practices X Construction Sequence • Other MINIMUM ESC REQUIREMENTS AFTER CONSTRUCTION X Stabilize Exposed Surface X Remove and Restore Temporary ESC Facilities X Clean and Remove All Silt and Debris X Ensure Operation of Permanent Facilities • Flag Limits of SAO and open space preservation areas • Other Figure #2 – Site Location AS ALWAYS, CALL 1-800-424-5555 BEFORECONSTRUCTION.TOPOGRAPHIC & BOUNDARY SURVEYBASIS OF BEARINGSLEGAL DESCRIPTIONVERTICAL DATUMSURVEYOR'S NOTESLEGENDVICINITY MAPN.T.S.REFERENCESSCALE: 1" =200'CONTROL MAPCITY OFRENTON4'06102.#6 4'06102.#64'06102.#6-'0&#..*1/'5+0%0'VJ564''6.7#Ä 6'&ÄÄ 7 5*''6':+56+0)%10&+6+105%10641./#2IN COMPLIANCE WITH CITY OF RENTON STANDARDSR-391902 TITLE REPORT REFERENCE:DENSITY CALCULATIONS:CITY OFRENTON4'06102.#6 4'06102.#64'06102.#6-'0&#..*1/'5+0%0'VJ564''6.7#Ä148TH AVE SE6'&ÄÄ 7':+56+0)%10&+6+1056121)4#2*+%/#2IN COMPLIANCE WITH CITY OF RENTON STANDARDS5*''6R-391903 Figure 3 – Drainage Basins, Subbasins, and Site Characteristics SITE Figure 4 – Soils TIR Section 2: Conditions and Requirement Summary Section 1.2 Core Requirements Core Requirement #1: Discharge at Natural Location The subject property has a natural channel located at the southwest corner of the property which flows offsite and becomes a “well” defined drainage channel downstream of the property. This will be the developed discharge location. Core Requirement #2: Offsite Analysis An upstream and downstream analysis has been provided within this Report within TIR Section 3. There were no identified of offsite flooding, erosion, drainage or water quality problems created or aggravated by the proposed project. Core Requirement #3: Flow Control The subject property is located within the City of Renton, Flow Control Duration Standard, Forested Conditions. An onsite flow control facility will be installed (stormwater vault) in the southwest corner of the development which will provide and be designed to perform to the required Duration Standards. The stormwater flow control (detention) sizing of the stormwater vault can be found within TIR Section 4 of this Report. Core Requirement #4: Conveyance System The proposed onsite and offsite conveyance systems have been analyzed and designed to meet the City of Renton amendments dated February 2010. All new pipes and catch basin will be sized to provide capacity for the 25-year event and the catch basins will have a minimum of 6” of freeboard above the 25-year event. The review and analysis of this proposed conveyance system includes calculations using the “Rational Method of Analysis” at the 25-year event. The design and analysis of the new system can be found in TIR Section 5 of this Report. The design of the proposed new system meets this Core requirement. Core Requirement #5: Erosion and Sediment Control A Temporary Erosion and Sediment Control Plan has been designed and provided as part of utility permit plan set. The implementation of these plans during construction will provide erosion and sedimentation control during the construction process. The erosion and sedimentation control plans are designed to minimize downstream impacts of the public storm system from the transportation of sediments, silts, and erosion. A Washington State Department of Ecology construction discharge NPDES permit has been applied for and will be obtained prior to start of construction. An erosion control specialist (CESL) will be assigned to this project to monitor and provide input to the contractor during the construction process. Erosion and sediment control will be monitored and reported to the Department of Ecology has required under the NPDES permit. Core Requirement #6: Maintenance and Operations The utility permit plans have identified the public and private storm systems on the project. The stormwater vault and tract will be owned by the homeowner’s association. The maintenance and operation of the internal portion of the stormwater vault will be provide by the City of Renton. The public storm systems identified by the utility permit plans will be maintained by the City of Renton. The private storm systems located on private property will be maintained by the home owner. TIR Section 10 of this Report provides routine maintenance requirements for the new facilities on this project. Core Requirement # 7: Financial Guarantees and Liability Financial Guarantees and Liabilities will be provided to the City of Renton as part of the issuance of the utility construction permit to construct the flow control facilities, storm conveyance systems, erosion control measures, road improvements and street lighting. A Bond Quantity worksheet has been provided within TIR Section 9 to provide support information to the City of Renton to determine financial requirements for bonds, fees, and sureties. Core Requirement No. 8 – Water Quality The subject project is required to provide water quality treatment. The water quality sizing is provided within TIR Section 4 of this Report. The water quality (dead storage) and sedimentation will be provided in the lower portion of the proposed stormwater vault. Section 1.3 Special Requirements Special Requirement #1: Other Adopted Area-Specific Requirements This project is not in a designated area included in an adopted master drainage plan, basin plan, salmon conservation plan, stormwater compliance plan, flood hazard reduction plan, or shared facilities drainage plan as identified under the City of Renton amendments to the King County Surface Water Design Manual dated February 2010. Special Requirement #2: Flood Hazard Area Delineation This project does not contain or adjacent to a flood hazard area for a river, stream, lake, wetland, closed depression, marine shoreline within the City of Renton. There are no regulations within the City of Renton amendments dated February 2010 to study flood hazards on this property. Special Requirement #3: Flood Protection Facilities The subject property does not rely on any flood protection facilities or proposes to modify or construct a new flood protection faciality. Special Requirement #4: Source Control The proposed project does not require a commercial building or commercial site development permit. Special Requirement #5: Oil Control The proposed project is a single-family residential subdivision. This project does not meet the requirements of a high-use site. Special Requirement #6: Aquifer Protection Area The proposed site development is not within an Aquifer Protection Area (APA) zone 1 or zone 2 as identified on the attached Groundwater Protection Areas map dated 01/09/2014 Preliminary Plat Conditions of Approval DECISION Dated June 29, 2016 1. All street names were provided by City of Renton and added to the construction plans. 2. All lot corners have a minimum 15-foot radius at street intersections. 3. All side sewers are extended onto the lots at a minimum of 8 feet. 4. All franchise utilities shall be installed underground within a 10-foot easement located along the frontage of all lots; the final franchise plans shall be submitted and approved for location by the City of Renton prior to installation. 5. The TV conduits shall be installed underground within the 10-foot franchise utility easement on the lots. The TV utility plans shall be submitted and approved for location by the City of Renton prior to installation. 6. There were no mitigation measures from the DNS issued on May 2, 2016. 7. A demolition permit will be obtained from the City of Renton prior to any removal of existing structures from the property. 8. Tract C has been approved for setbacks for the monopole II after the public hearing. The City of Renton Planning Department has approved the layout and setbacks of Tract C as shown on the construction drawings. 9. A draft version of the HOA agreement shall be submitted to the City of Renton for review and approval at the time of final plat submittal and review. 10. A detailed landscape plan has been provided as part of the construction plans for approval by the City of Renton. 11. A final tree retention plan has been provided as part of the construction plans for approval by the City of Renton. 12. Lot 12 has been revised since the preliminary plat to provide the necessary 35 feet of street frontage. The lot layout has been provided within the construction plans for approval by the City of Renton. 13. A note shall be provided on the final plat stating the average lot areas. This shall be provided as part of the final plat submittal for review and approval by the City of Renton. TIR Section 3: Offsite Analysis TASK 1: Study Area Definition and Maps The project has a downstream, upstream contributing, and off site non-contributing areas. Within the task Downstream will be an overview and analysis of the downstream system approximately 3,300 feet downstream. The Upstream area from the property to the east will be reviewed and designed to bypass the on-site facility. The Off Site non-contributing area to the east of the upstream area will be looked at and discussed within the “Upstream Section – Task 1 below. DOWNSTREAM MAP UPSTREAM MAP and Discussion There are two portions to the Upstream Area: An area that flows onto the project called “Upstream Area” shown on the map, next page; and the upstream “Off Site Non-contributing Area”. Upstream Area – contributing: This area upstream is an adjacent property to the east that flows onto the project. There is 1.21 acres of this property that flows to the west onto the project. The property is undeveloped as an existing house, driveway, landscaped lawn and mostly pasture. This area will be sized and analysis to bypass the Renton 14 storm water facility. The KCRTS modeling of the “Upstream Area” shows the existing 100-year runoff as 0.345 cfs and the pre- developed (historic) runoff as 0.132 cfs. These 100-year flow rates are less than 0.5 cfs and therefore the area can bypass the onsite storm facility. Note: the “historic flow rate” at the developed condition is required under the 2009 City of Renton Storm Water Manual. A swale along the east side of the Renton 14 project will be used to collect and convey the runoff around the project. At the southeast corner of Renton 14, a catch basin will be installed to collect and convey the runoff to the rock pad at the southwest corner of the project. Off Site Non-Contributing Area: Off Site Area #1 – this area is the front of the residence to the east, there is a ridge in front of the existing house that forces the runoff to the north and northwest. The runoff is collected along the south side of NE 4th street and flows to the west to a “depression” (hole) located at the inlet of an 18” pipe that flows to the northeast across NE 4th Street. The pipe end at the north side of NE 4th Street is 24”. Photos of the pipe ends at attached. This area does not contribute to the project NOR does this area contribute to the area to the west along NE 4th Street. Off Site Area #2 – the area to the east of the “Upstream Area” slopes to the south and east. This area does no contribute to the Renton 14 project. The area sheet flows to the south and southeast onto the abutting property to the east. UPSTREAM BYPASS AREA (EXISTING CONDITION) UPSTREAM BYPASS AREA (DEVELOPED <<historic>>CONDITION) TASK 2: Resource Review Online maps from Google Earth and City of Renton storm water maps were reviewed before the downstream system was walked. TASK 3: Field Inspection Downstream System: The subject property discharges in a defined broad channel at the southwest corner at the natural discharge point. The channel becomes “v” shape about 80 feet downstream of the property. The discharge from the site continues to the southwest into a heavily vegetated area of un-developed property to the south. Along the flow path offsite, the flow becomes more concentrated and forms a channel within the open space area in the northeast corner of Quincy Avenue NE and NE 2nd Street, photos A. There is an inlet structure on the north side of NE2nd Street that conveys the flow across the street and into an open space area to the south. The inlet structure is clean and exposed and does not appear to have a capacity issue. The flow then continues in a southwest direction within the open space crossing NE 1st Place at Orcas Avenue NE, photos B. The inlet on the north side of NE 1st Place is covered in leaves and small tree branches. The inlet is conveying flows at the time of observation. The flow continues to the southwest in behind a developed property of single family homes. Access to the channel in this area was difficult to follow the channel. The flow (channel) is exposed on the north side of a King County park property (un- developed) on the south side of the single-family development. The flow continues to the south across the King County parcel within a well-defined channel. The channel enters an inlet structure to the north of 148th Place SE, photos C. The inlet is clean and maintained – no debris or obstacles blocking inlet. At this point, the flow enters a closed storm system flowing south through an older development. The system was not followed beyond this point downstream. Point C is located over 3,800 feet downstream of the property. The downstream system from the subject property to point C (north of 148th Place SE) appears to have adequate capacity to convey the developed runoff from the project. A Level 2 analysis is attached to provide a calculated review of the natural discharge point in the southwest corner of the property. After review, the downstream channel is adequate to provide for the fully developed discharge of the 100-year event. Renton 14 02/13/2018 Downstream Level 2 Analysis The natural point of discharge from the Renton 14 project and the upstream (off site) contributing area (see map page 58 of TIR) is a defined drainage course which exits the Renton 14 property at the southwest corner. The channel is broad where it leaves the project and becomes more defined as a “v” shaped channel approximately 60 feet downstream from the property corner. This portion, the first 135 feet below the property corner, was analyzed using the Level 2 downstream requirements. A rag tape, metal tape, and hand level were used to determine cross sections and distance from the southwest corner of the project. The channel is located on the property to the south, King County Open Space, and flows west, then turns south continuing south crossing SE 2nd Street near the intersection of Rosario and SE 2nd Street. A continuation and further discussion on the downstream drainage course can be found within the downstream analysis section of the TIR. This analysis has been performed on the upper reach of the drainage course where it leaves the project (Renton 14) and becomes defined as channeled flow approximately 135 feet downstream. Three cross sections were measured in the field and analyzed for conveyance of the 100 year fully developed discharge from the upstream area contributing to the open channel. The 100 year fully developed discharge from the upstream area is defined as: The Renton 14 project vault discharge PLUS the Renton 14 bypass area discharge PLUS the offsite upstream area (east of Renton 14). The 100-year flow rate (after Renton 14 developed site) is: Renton 14 vault discharge @ 100 year = 1.00 cfs PLUS Renton 14 bypass area discharge @ 100 year = 0.019 cfs PLUS Upstream offsite area @ 100 year = 0.354 cfs. The 100-flow rate of 1.37 cfs will be used to analyze the downstream open channel below the discharge point on the Renton 14 project. Note: All 100-year flow rates are from hydrology modeling of storm water vault TIR Section 4, part C and upstream contributing area TIR Section3, Task 1. The cross sections were analyzed for a flow depth at 1.37 cfs; the attached calculations use an assumed depth of flow and then calculates the related flow; this flow is then compared to 1.37 cfs to determine if a greater or smaller flow depth is needed to re-run the calculations. The existing downstream drainage course is heavily covered with brush, irregularly shaped, and vegetation within the bottom area. A Manning’s number of (n) 0.150 was used to define the friction coefficient of the drainage course. Based upon the attached analysis of the downstream system, the 100-year developed flow rate would generate a flow depth ranging from 4 to 8 inches. This rate would be contained within the downstream drainage course and should not create an erosion or overflow condition. The downstream drainage course has adequate capacity to convey the developed 100-year discharge from the Renton 14 project and the existing 100 year upstream offsite area. TASK 4: Drainage System Description and Problem Descriptions The existing drainage system 3,800 feet downstream of the property consists of an open channel within a forested corridor with roadway culverts where the channel crosses the public streets. The system was walked the length of the open channel with access along a nature trail within the forest corridor. The downstream system has been observed on several occasions during the winter of 2016-2017. The system appears to have adequate capacity with no indications of overtopping or scouring. TASK 5: Mitigation of existing or potential Problems There is no required mitigation necessary for the downstream system. The proposed project will be developed unitizing the storm water management requirements of the City of Renton Storm Water Manual. The developed discharge from the property will be less than the existing discharge due to the required modeling matching the pre-developed forest condition. A- flow spreader, board rock pad, will be provided at the discharge point of the storm water vault to provide a broader (sheet) flow during the developed condition. TIR Section 4: Flow Control and Water Quality Analysis and Design Existing Site Hydrology (Part A): The project site is 210,595 square feet in size. The existing characteristics and land cover will not be utilized for this project. The project is located within the “Existing Conditions – Forested conditions” drainage area; therefore, the project will utilize a fully forested condition as the pre- developed modeling. The existing site is under laid by Alderwood series soils classified as Vashon Glacial Tills (as identified within the Geotechnical Report within this Report. This type of soils is hard and compact with pockets of high groundwater during the wet weather season. The existing drainage on the project sheet flows towards the southwest corner where the project discharges into a defined drainage channel on the property next door. A new flow control facility will be placed in the southwest corner to collect the developed runoff and discharge back into the offsite channel. TITLE REPORT REFERENCE:DENSITY CALCULATIONS:CITY OFRENTON4'06102.#6 4'06102.#64'06102.#6-'0&#..*1/'5+0%0'VJ564''6.7#Ä148TH AVE SE6'&ÄÄ 7':+56+0)%10&+6+1056121)4#2*+%/#2IN COMPLIANCE WITH CITY OF RENTON STANDARDS5*''6R-391903 Developed Site Hydrology (Part B): Drainage Review Requirements Project Characteristics: Total Site Area = 210,595 square feet Offsite Improvements: Installation of a 12” storm pipe extension along NE 4th Street Total Improvement: Value of development cost more than $100,000 Developed Impervious = 80,087 square feet (new plus replaced) Drainage Review: Based upon Table 1.1.2.A., the project drainage review meets “Full Drainage Review”. The project will be developed to provide storm water detention for the area of the project that can gravity flow into the facility in the southwest corner of the project. A portion of the westerly side of the project is below the overflow elevation of the vault and therefore will be designed to bypass the storm water facility, further discussion of this bypass area is contained below. Developed Site data: 15 single-family lots ranging from 7720 to 15286 square feet in size. A Storm Water Tract (Tract A) 11,764 square feet An Access/Emergency Tract (Tract B) 2,749 square feet A Utility Tract (Tract C) 1,744 square feet Public roadway 40,794 square feet The project impervious and pervious surface breakdown of areas is attached as a Table to the Part C section of this Section 4. Developed Site Conditions (summary from table): On-site contributing to storm water vault Dedicated R/W: 40,794 sq. feet (0.94 acres) Impervious 30,549 sq. feet (0.70 acres) Pervious 10,245 square feet (0.24 acres) Tract A-C: 12,905 square feet (0.30 acres) Impervious 5,999 square feet (0.138 acres) Pervious 6,906 square feet (0.159 acres) Lots 1-15: 152,655 square feet (3.505 acres) Impervious 54,376 square feet (1.248 acres) Pervious 98,279 square feet (2.256 acres) Areas to vault (summary): Impervious 2.087 acres Pervious 2.650 acres Bypass Area: ** Rear (west of wall) lot 3 & 4 and portion of Tract A Impervious 185 square feet (0.004 acres) Pervious 4,056 square feet (0.093 acres) ** The project bypass area must be verified for compliance with Section 1.2.3.2.E of the 2009 Surface Water Design Manual Amendment. Mitigation of Target Surfaces that Bypass facility: 1. The bypass area and the flow control (vault) discharge at the same point of convergence, at the southwest corner of the property; therefore, the two discharges converge less than ¼ mile downstream; 2. The developed 100-year flow rate is 0.019 cfs; therefore, this is less than the allowable of 0.40 cfs. Peak discharge from the bypass are does not increase the 100-year existing condition flow rate by 0.40 cfs. 3. Runoff from the bypass area does not create a significant adverse downstream impact; 4. There are no water quality requirements for the bypass area; no PGIS contributes to the bypass area 5. Compensatory mitigation must be provided by flow control facility. The flow control facility (vault) has been sized to reduce the allowable discharge by the bypass flow rate. The combination of the bypass flow and the vault discharge flow are equal to or less than the historic allowable flow rate. This condition has been met. The project will be modeled using KCRTS. The existing historical condition (forested) was modeled to provide parameters for the design outfall match of the proposed storm water vault. Further modeling and calculations can be found within Part C. Renton 14 PlatA(T) 210,595 sq. feet9/2/2017Developed ConditionMODEL AS:(sq. ft.)ImperviousPerviousDedicated R/W40794sq. feetasphalt(PGIS)20292sidewalk 7825D/W apron(PGIS)15 @ 128 each1920(PGIS)2 @ 96 each192(PGIS)2 @ 160 each320landscaping10245TractsA - vault8412sq. feetaccess (PGIS)2775landscape 5637B - access2749sq. feetasphalt(PGIS)2749landscaping0C - utility1744sq. feetstructure475landscaping1269Lot AreaLots 1-15152,655sq. feetHouse/roof/driveway54,376 Landscaping98,279206,354 90,924 115,430206,354 2.09 2.65ACRESBypass Area (SW corner)Lots 3-4889 sq. feetLandscaping889Tract A3,352 sq. feetBypass1853167210,595 1854056bypass basin0.00 0.09ACRES Renton 14 PlatMaximum Impervious per Lot** Maximum Mitigation* Max. 40% Imp.ImperviousLot Areareduced imperviousAllowed on LotPerforated RestrictiveLot #(sq. feet)(sq. feet)(sq. feet)Pipe ConnectionCovenant11483359334000yesyes21528661144000yesyes3974338974000yesyes4974338974000yesyes5898835953500yesyes6772030883088yesyes7790131603088yesyes8898635943500yesyes9951638063600yesyes10951338053600yesyes11952938123600yesyes12998039923600yesyes131375055003600yesyes14905636223600yesyes15900036003600yesyes15354454376* maximum impervious surface allowed under RestrictiveCovenant BMP** maximum impervious allowed on lot is EITHER 4,000 sq. feetOR column (3) whichever is less. Performance Standards (Part C): Area-specific flow control facility standards: From the “Flow Control Application Map”, reference 11-A, the project discharge is required to meet Flow Control Duration Standard (Forested Conditions). Flow control BMP’s are required for this project and will be further evaluated within Part D of this Section. Conveyance system capacity standards: The new conveyance system will be analyzed and designed to meet the developed 25-year flow rates. Capacity within the catch basins shall have 6” (0.5’) of freeboard above the 25-year hydraulic grade within the catch basin. Area-specific water quality treatment menu: As identified under Section 1.2.8.1.A. “Required Treatment Menu”, this project is NOT a commercial, industrial or multifamily land use and is NOT a road project with 7,500 ADT. Therefore, the project is required to provide Basic Water Quality Treatment. Water Quality sizing calculation can be found in Part D od this Section The Renton 14 project is subject to the City’s 2009 Surface Water Design Manual Amendment (City Manual). This essentially adopts the 2009 King County Surface Water Design Manual (County Manual), with some minor modifications. The project is subject to the “Flow Control Duration Standard Matching Forested Site Conditions”, as outlined on Page 1-35 of the City Manual. Here is a discussion of those requirements, and how they have been achieved: · The model must assume the historic site conditions to be fully forested. This is shown in the input parameters on the first page of the attached calculations. · The model must meet the requirements listed under “Evaluating Flow Control Performance”, as shown on Page 3-43 of the County Manual. This section of the manual is not modified by the City Manual. The requirements of this section are: 1. The post-development flow duration curve lies strictly on or below the predevelopment curve at the lower limit of the range of control. This condition has been met. It is presented graphically on the last page of the attached calculations. The numerical analysis presented on that same page indicates a duration reduction of nearly 10% at the lower limit (1/2 the 2-yr peak). 2. At any duration within the range of control, the post-development flow is less than 1.1 times (10%) the predevelopment flow. This condition has been met. The numerical analysis provided on the last page of the attached calculations indicates that the maximum positive excursion through the range of control is only 5.7%. This would be a maximum excursion of 1.057 times the predevelopment flow. 3. The target duration curve may not be exceeded along more than 50% of the range of control. Developed Basin A(i) C(n)=0.90A(p) C(n)=0.25R/WAccessD/WA(T)Impervious(PGIS)House(PGIS)OtherA(i)PerviousBasinAreassq. ft.sq. ft.sq. ft.sq. ft.sq. ft.AcresSq. ft.Acres2196202572600012000.2298480.233627223770.0538950.09412005020.016980.025664627494750.0734220.08612006700.025300.017368020150.0516650.0484879039031200024000.42304870.7010182410110.028130.0211542124590.0629620.0712265203962838818000.32123700.281418249360.028880.0215230013350.039650.0216190372711538812000.2197380.2218670030480.0736520.0819582030480.0727720.06204950027751360024000.43307250.71Bypass42411850.0040560.09 This condition has been met. From the graphic representation on the final page of the calculations, it can be visually observed that most of the post-developed curve lies beneath the target curve. The numerical analysis provided on that same sheet evaluates 14 data points, and of those, only 4 of those data points are exceeded (approximately 28% of the range of control). 4. The peak flow at the upper end of the range of control (reduced, 25-year; historical, 50 year) may not exceed predeveloped levels by more than 10%. This condition has been met at the point of compliance. The analysis used the reduced record, and the peak flows for the 25-yr event are as follows: 25-yr Historic Peak Flow for Project: 0.31-cfs 25-yr Developed Peak Flow at the Point of Compliance: 0.38 cfs 25-yr Peak Flow Increase: 1.1% · Page 1-35 of the City Manual also requires the design to match the 2-yr and 10-yr peak discharge rates at point of compliance. Here is a summary of those rates for the project: 2-yr Peak Rate (Historic): 0.134-cfs 2-yr Peak Rate (Developed): 0.13-cfs 10-yr Peak Rate (Historic): 0.234-cfs 10-yr Peak Rate (Developed): 0.20-cfs Historic Project Basin Flow Frequency Analysis Time Series File:predev.tsf Project Location:Sea-Tac ---Annual Peak Flow Rates--- -----Flow Frequency Analysis------- Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob (CFS) (CFS) Period 0.305 2 2/09/01 18:00 0.390 1 100.00 0.990 0.083 7 1/06/02 3:00 0.305 2 25.00 0.960 0.226 4 2/28/03 3:00 0.234 3 10.00 0.900 0.008 8 3/24/04 20:00 0.226 4 5.00 0.800 0.134 6 1/05/05 8:00 0.197 5 3.00 0.667 0.234 3 1/18/06 21:00 0.134 6 2.00 0.500 0.197 5 11/24/06 4:00 0.083 7 1.30 0.231 0.390 1 1/09/08 9:00 0.008 8 1.10 0.091 Computed Peaks 0.361 50.00 0.980 25-year historic discharge Developed Project Basin Flow Frequency Analysis Time Series File:dev.tsf Project Location:Sea-Tac ---Annual Peak Flow Rates--- -----Flow Frequency Analysis------- Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob (CFS) (CFS) Period 0.744 5 2/09/01 2:00 1.55 1 100.00 0.990 0.567 8 1/05/02 16:00 0.902 2 25.00 0.960 0.902 2 2/27/03 7:00 0.828 3 10.00 0.900 0.570 7 8/26/04 2:00 0.785 4 5.00 0.800 0.697 6 10/28/04 16:00 0.744 5 3.00 0.667 0.785 4 1/18/06 16:00 0.697 6 2.00 0.500 0.828 3 10/26/06 0:00 0.570 7 1.30 0.231 1.55 1 1/09/08 6:00 0.567 8 1.10 0.091 Computed Peaks 1.33 50.00 0.980 Bypass Basin Flow Frequency Analysis Time Series File:bypass.tsf Project Location:Sea-Tac ---Annual Peak Flow Rates--- -----Flow Frequency Analysis------- Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob (CFS) (CFS) Period 0.008 3 2/09/01 2:00 0.019 1 100.00 0.990 0.004 7 1/05/02 16:00 0.010 2 25.00 0.960 0.010 2 2/27/03 7:00 0.008 3 10.00 0.900 0.002 8 3/24/04 19:00 0.008 4 5.00 0.800 0.004 6 1/05/05 8:00 0.007 5 3.00 0.667 0.008 4 1/18/06 16:00 0.004 6 2.00 0.500 0.007 5 11/24/06 3:00 0.004 7 1.30 0.231 0.019 1 1/09/08 6:00 0.002 8 1.10 0.091 Computed Peaks 0.016 50.00 0.980 Developed 100-year bypass flow rate 25-year discharge rate Vault Design Retention/Detention Facility Type of Facility: Detention Vault Facility Length: 128.00 ft Facility Width: 51.00 ft Facility Area: 6528. sq. ft Effective Storage Depth: 7.50 ft Stage 0 Elevation: 503.10 ft Storage Volume: 48960. cu. ft Riser Head: 7.50 ft Riser Diameter: 12.00 inches Number of orifices: 3 Full Head Pipe Orifice # Height Diameter Discharge Diameter (ft) (in) (CFS) (in) 1 0.00 1.00 0.074 2 4.70 1.88 0.160 4.0 3 6.90 1.50 0.047 4.0 Top Notch Weir: None Outflow Rating Curve: None Stage Elevation Storage Discharge Percolation (ft) (ft) (cu. ft) (ac-ft) (cfs) (cfs) 0.00 503.10 0. 0.000 0.000 0.00 0.01 503.11 65. 0.001 0.003 0.00 0.02 503.12 131. 0.003 0.004 0.00 0.03 503.13 196. 0.004 0.005 0.00 0.04 503.14 261. 0.006 0.006 0.00 0.05 503.15 326. 0.007 0.006 0.00 0.06 503.16 392. 0.009 0.007 0.00 0.07 503.17 457. 0.010 0.007 0.00 0.08 503.18 522. 0.012 0.008 0.00 0.09 503.19 588. 0.013 0.008 0.00 0.24 503.34 1567. 0.036 0.013 0.00 0.39 503.49 2546. 0.058 0.017 0.00 0.53 503.63 3460. 0.079 0.020 0.00 0.68 503.78 4439. 0.102 0.022 0.00 0.83 503.93 5418. 0.124 0.025 0.00 0.98 504.08 6397. 0.147 0.027 0.00 1.12 504.22 7311. 0.168 0.029 0.00 1.27 504.37 8291. 0.190 0.031 0.00 1.42 504.52 9270. 0.213 0.032 0.00 1.56 504.66 10184. 0.234 0.034 0.00 1.71 504.81 11163. 0.256 0.035 0.00 1.86 504.96 12142. 0.279 0.037 0.00 2.01 505.11 13121. 0.301 0.038 0.00 2.15 505.25 14035. 0.322 0.040 0.00 2.30 505.40 15014. 0.345 0.041 0.00 2.45 505.55 15994. 0.367 0.042 0.00 2.59 505.69 16908. 0.388 0.044 0.00 2.74 505.84 17887. 0.411 0.045 0.00 2.89 505.99 18866. 0.433 0.046 0.00 3.03 506.13 19780. 0.454 0.047 0.00 3.18 506.28 20759. 0.477 0.048 0.00 3.33 506.43 21738. 0.499 0.049 0.00 3.48 506.58 22717. 0.522 0.051 0.00 3.62 506.72 23631. 0.543 0.052 0.00 3.77 506.87 24611. 0.565 0.053 0.00 3.92 507.02 25590. 0.587 0.054 0.00 4.06 507.16 26504. 0.608 0.055 0.00 4.21 507.31 27483. 0.631 0.056 0.00 4.36 507.46 28462. 0.653 0.057 0.00 4.51 507.61 29441. 0.676 0.058 0.00 4.65 507.75 30355. 0.697 0.059 0.00 4.70 507.80 30682. 0.704 0.059 0.00 Detention volume required 4.72 507.82 30812. 0.707 0.060 0.00 4.74 507.84 30943. 0.710 0.062 0.00 4.76 507.86 31073. 0.713 0.066 0.00 4.78 507.88 31204. 0.716 0.071 0.00 4.80 507.90 31334. 0.719 0.077 0.00 4.82 507.92 31465. 0.722 0.085 0.00 4.84 507.94 31596. 0.725 0.094 0.00 4.86 507.96 31726. 0.728 0.097 0.00 5.00 508.10 32640. 0.749 0.113 0.00 5.15 508.25 33619. 0.772 0.126 0.00 5.30 508.40 34598. 0.794 0.136 0.00 5.44 508.54 35512. 0.815 0.146 0.00 5.59 508.69 36492. 0.838 0.154 0.00 5.74 508.84 37471. 0.860 0.162 0.00 5.89 508.99 38450. 0.883 0.170 0.00 6.03 509.13 39364. 0.904 0.177 0.00 6.18 509.28 40343. 0.926 0.183 0.00 6.33 509.43 41322. 0.949 0.190 0.00 6.47 509.57 42236. 0.970 0.196 0.00 6.62 509.72 43215. 0.992 0.202 0.00 6.77 509.87 44195. 1.015 0.208 0.00 6.90 510.00 45043. 1.034 0.213 0.00 6.92 510.02 45174. 1.037 0.214 0.00 6.93 510.03 45239. 1.039 0.216 0.00 6.95 510.05 45370. 1.042 0.219 0.00 6.96 510.06 45435. 1.043 0.222 0.00 6.98 510.08 45565. 1.046 0.227 0.00 6.99 510.09 45631. 1.048 0.233 0.00 7.01 510.11 45761. 1.051 0.237 0.00 7.03 510.13 45892. 1.054 0.239 0.00 7.17 510.27 46806. 1.075 0.254 0.00 7.32 510.42 47785. 1.097 0.267 0.00 7.47 510.57 48764. 1.119 0.279 0.00 7.50 510.60 48960. 1.124 0.281 0.00 7.60 510.70 49613. 1.139 0.596 0.00 7.70 510.80 50266. 1.154 1.170 0.00 7.80 510.90 50918. 1.169 1.900 0.00 7.90 511.00 51571. 1.184 2.700 0.00 8.00 511.10 52224. 1.199 2.990 0.00 8.10 511.20 52877. 1.214 3.250 0.00 8.20 511.30 53530. 1.229 3.490 0.00 8.30 511.40 54182. 1.244 3.710 0.00 8.40 511.50 54835. 1.259 3.920 0.00 8.50 511.60 55488. 1.274 4.120 0.00 8.60 511.70 56141. 1.289 4.310 0.00 8.70 511.80 56794. 1.304 4.500 0.00 8.80 511.90 57446. 1.319 4.670 0.00 8.90 512.00 58099. 1.334 4.840 0.00 9.00 512.10 58752. 1.349 5.000 0.00 9.10 512.20 59405. 1.364 5.160 0.00 9.20 512.30 60058. 1.379 5.310 0.00 9.30 512.40 60710. 1.394 5.460 0.00 9.40 512.50 61363. 1.409 5.600 0.00 Hyd Inflow Outflow Peak Storage Stage Elev (Cu-Ft) (Ac-Ft) 1 1.55 1.00 7.67 510.77 50076. 1.150 2 0.74 0.28 7.49 510.59 48893. 1.122 3 0.90 0.20 6.46 509.56 42141. 0.967 4 0.83 0.19 6.25 509.35 40794. 0.937 5 0.78 0.13 5.20 508.30 33974. 0.780 6 0.70 0.10 4.88 507.98 31844. 0.731 7 0.57 0.06 4.45 507.55 29041. 0.667 8 0.57 0.04 2.35 505.45 15349. 0.352 Hyd R/D Facility Tributary Reservoir POC Outflow Outflow Inflow Inflow Target Calc 1 1.00 0.02 ******** 0.39 1.01 2 0.28 0.01 ******** ******* 0.29 3 0.20 0.01 ******** ******* 0.20 4 0.19 0.01 ******** ******* 0.19 25-year discharge from vault 25-year elevation of water level within vault 5 0.13 0.01 ******** ******* 0.13 6 0.10 0.00 ******** ******* 0.10 7 0.06 0.00 ******** ******* 0.06 8 0.04 0.00 ******** ******* 0.04 ---------------------------------- Route Time Series through Facility Inflow Time Series File:dev.tsf Outflow Time Series File:RDOut POC Time Series File:DSOut Inflow/Outflow Analysis Peak Inflow Discharge: 1.55 CFS at 6:00 on Jan 9 in Year 8 Peak Outflow Discharge: 1.00 CFS at 10:00 on Jan 9 in Year 8 Peak Reservoir Stage: 7.67 Ft Peak Reservoir Elev: 510.77 Ft Peak Reservoir Storage: 50076. Cu-Ft : 1.150 Ac-Ft Add Time Series:bypass.tsf Peak Summed Discharge: 1.01 CFS at 10:00 on Jan 9 in Year 8 Point of Compliance File:DSOut.tsf Flow Duration from Time Series File:rdout.tsf Cutoff Count Frequency CDF Exceedence_Probability CFS % % % 0.004 31402 51.210 51.210 48.790 0.488E+00 0.012 8030 13.095 64.305 35.695 0.357E+00 0.020 5861 9.558 73.863 26.137 0.261E+00 0.028 5404 8.813 82.676 17.324 0.173E+00 0.035 4720 7.697 90.373 9.627 0.963E-01 0.043 2221 3.622 93.995 6.005 0.600E-01 0.051 1636 2.668 96.663 3.337 0.334E-01 0.059 1532 2.498 99.162 0.838 0.838E-02 0.067 95 0.155 99.317 0.683 0.683E-02 0.075 29 0.047 99.364 0.636 0.636E-02 0.083 13 0.021 99.385 0.615 0.615E-02 0.091 14 0.023 99.408 0.592 0.592E-02 0.098 28 0.046 99.454 0.546 0.546E-02 0.106 38 0.062 99.516 0.484 0.484E-02 0.114 30 0.049 99.565 0.435 0.435E-02 0.122 40 0.065 99.630 0.370 0.370E-02 0.130 38 0.062 99.692 0.308 0.308E-02 0.138 18 0.029 99.721 0.279 0.279E-02 0.146 23 0.038 99.759 0.241 0.241E-02 0.153 19 0.031 99.790 0.210 0.210E-02 0.161 22 0.036 99.826 0.174 0.174E-02 0.169 12 0.020 99.845 0.155 0.155E-02 0.177 15 0.024 99.870 0.130 0.130E-02 0.185 20 0.033 99.902 0.098 0.978E-03 0.193 14 0.023 99.925 0.075 0.750E-03 0.201 10 0.016 99.941 0.059 0.587E-03 0.209 9 0.015 99.956 0.044 0.440E-03 0.216 10 0.016 99.972 0.028 0.277E-03 0.224 1 0.002 99.974 0.026 0.261E-03 0.232 1 0.002 99.976 0.024 0.245E-03 0.240 0 0.000 99.976 0.024 0.245E-03 0.248 3 0.005 99.980 0.020 0.196E-03 0.256 2 0.003 99.984 0.016 0.163E-03 0.264 2 0.003 99.987 0.013 0.130E-03 0.271 3 0.005 99.992 0.008 0.815E-04 0.279 3 0.005 99.997 0.003 0.326E-04 Flow Duration from Time Series File:dsout.tsf Cutoff Count Frequency CDF Exceedence_Probability CFS % % % 0.004 31521 51.404 51.404 48.596 0.486E+00 0.012 8078 13.174 64.578 35.422 0.354E+00 0.020 5857 9.552 74.129 25.871 0.259E+00 0.028 5486 8.947 83.076 16.924 0.169E+00 0.036 4596 7.495 90.571 9.429 0.943E-01 100 discharge flow rate from vault Elevation @ 100 year discharge Volume @ 100 year discharge 0.044 2145 3.498 94.069 5.931 0.593E-01 0.052 1680 2.740 96.809 3.191 0.319E-01 0.060 1399 2.281 99.090 0.910 0.910E-02 0.068 140 0.228 99.318 0.682 0.682E-02 0.076 28 0.046 99.364 0.636 0.636E-02 0.085 13 0.021 99.385 0.615 0.615E-02 0.093 13 0.021 99.406 0.594 0.594E-02 0.101 34 0.055 99.462 0.538 0.538E-02 0.109 34 0.055 99.517 0.483 0.483E-02 0.117 32 0.052 99.569 0.431 0.431E-02 0.125 39 0.064 99.633 0.367 0.367E-02 0.133 31 0.051 99.684 0.316 0.316E-02 0.141 23 0.038 99.721 0.279 0.279E-02 0.149 22 0.036 99.757 0.243 0.243E-02 0.157 21 0.034 99.791 0.209 0.209E-02 0.165 22 0.036 99.827 0.173 0.173E-02 0.173 12 0.020 99.847 0.153 0.153E-02 0.181 15 0.024 99.871 0.129 0.129E-02 0.189 19 0.031 99.902 0.098 0.978E-03 0.197 16 0.026 99.928 0.072 0.718E-03 0.205 9 0.015 99.943 0.057 0.571E-03 0.213 10 0.016 99.959 0.041 0.408E-03 0.221 8 0.013 99.972 0.028 0.277E-03 0.229 1 0.002 99.974 0.026 0.261E-03 0.237 1 0.002 99.976 0.024 0.245E-03 0.245 1 0.002 99.977 0.023 0.228E-03 0.253 2 0.003 99.980 0.020 0.196E-03 0.261 2 0.003 99.984 0.016 0.163E-03 0.270 2 0.003 99.987 0.013 0.130E-03 0.278 3 0.005 99.992 0.008 0.815E-04 0.286 3 0.005 99.997 0.003 0.326E-04 Duration Comparison Anaylsis Base File: predev.tsf New File: dsout.tsf Cutoff Units: Discharge in CFS -----Fraction of Time----- ---------Check of Tolerance------- Cutoff Base New %Change Probability Base New %Change 0.067 | 0.95E-02 0.70E-02 -26.5 | 0.95E-02 0.067 0.060 -9.8 0.085 | 0.63E-02 0.61E-02 -3.1 | 0.63E-02 0.085 0.078 -8.7 0.103 | 0.49E-02 0.52E-02 5.6 | 0.49E-02 0.103 0.107 3.6 0.122 | 0.37E-02 0.39E-02 6.2 | 0.37E-02 0.122 0.125 2.3 0.140 | 0.28E-02 0.28E-02 -1.1 | 0.28E-02 0.140 0.139 -0.8 0.158 | 0.22E-02 0.20E-02 -8.9 | 0.22E-02 0.158 0.154 -2.7 0.177 | 0.15E-02 0.14E-02 -4.4 | 0.15E-02 0.177 0.175 -0.9 0.195 | 0.10E-02 0.80E-03 -21.0 | 0.10E-02 0.195 0.188 -3.4 0.213 | 0.62E-03 0.41E-03 -34.2 | 0.62E-03 0.213 0.202 -5.4 0.231 | 0.34E-03 0.26E-03 -23.8 | 0.34E-03 0.231 0.217 -6.2 0.250 | 0.21E-03 0.23E-03 7.7 | 0.21E-03 0.250 0.251 0.5 0.268 | 0.16E-03 0.13E-03 -20.0 | 0.16E-03 0.268 0.262 -2.1 0.286 | 0.11E-03 0.16E-04 -85.7 | 0.11E-03 0.286 0.272 -4.8 0.304 | 0.16E-04 0.00E+00 -100.0 | 0.16E-04 0.304 0.286 -6.0 Maximum positive excursion = 0.006 cfs ( 6.2%) occurring at 0.090 cfs on the Base Data:predev.tsf and at 0.096 cfs on the New Data:dsout.tsf Maximum negative excursion = 0.013 cfs (-17.4%) occurring at 0.077 cfs on the Base Data:predev.tsf and at 0.064 cfs on the New Data:dsout.tsf Flow Control System (Part D): Based upon the City of Renton Drainage Manual, the following steps are required to determine the mitigation of storm water runoff of the developed project: Full Dispersion – N/G (no good) – The property does not have adequate flow path lengths to allow for full dispersion; Full Infiltration – N/G – The soils have been classified by the Geotechnical Engineer as “fine loamy sands” with a low permeability rate; Alderwood Series soils w/ high ground water present. These soils are not adequate for full infiltration per the Drainage Manual. The Geotechnical Engineer does not recommend infiltration or retention of onsite runoff due to the high ground water table and poor draining soils. Limited Infiltration – N/G- With the presents of a high ground water table, the use of infiltration BMP’s is not recommended by the geotechnical Engineer or allowed by the City manual. Limited Dispersion – N/G – The soils, the high ground water table and the lack of available flow path do not allow for these types of BMP’s. Perforated Pipe Connection – This BMP will be used on the lots as each house connects to the onsite stormwater facility. The project will be sized for a storm water facility (vault) to provide runoff control. The facility sizing calculations can be found attached to this section. The existing historic conditions of the site are required to be analyzed as “Forested Site Conditions” Developed Project Area breakdown has been attached to indicate the developed conditions of the project after BMP mitigations have been account for and shown. From the developed project area breakdown, the KCRTS model was used to compute the existing and developed runoffs from the project. To meet the performance standard and allow for the bypass area to discharge, the storm water detention volume was calculated as 48,960 cubic feet per the attached calculations at elevation 510.60. The proposed vault (within the active (detention) portion) is 510.60’ overflow – 503.10’ outlet (7.50’ active storage). The detention portion of the vault would be 128’ x 51’ (wide) x 7.50’ deep (detention) OR 48,960 cubic feet. The proposed vault is adequately sized for flow control for the proposed development. Water Quality System (Part E): The proposed project will include the installation of a wet sump (dead storage) within the proposed storm water vault for water quality treatment. Check project for Water Quality Exemption: Section 1.2.8.1 Surface Area Exemptions: Project creates greater than 5,000 square feet of new PGIS (30,963 sq. feet proposed PGIS) – new roads, emergency access paving, and new proposed driveways. Therefore, water quality treatment is required. Water Quality Sizing – calculations for the water quality volume are attached to this section. The calculated volume required is 12,951 cubic feet of dead storage. Cell #1 and Cell #2 will store the required water quality for the storm water vault. Between 25-35% of the required water quality will be contained within Cell #1. Proposed Cell #1 water quality volume: 25’ wide x 36’ long x (503.10-497.85) – volume provided = 4,725 cubic feet. Provided Cell #2 water quality volume: 25’ x 92’ x (503.10-497.85) = 12,075 cu. feet Total Water Quality provided = 16,800 cu. feet > 12,291 cu. feet OKAY Cell #1 check percentage: 4725/16800 = 28.13% between 25-35% OKAY Check for average sediment storage of 12” (1’) within Cell #1 Calculate average sediment volume of 12”: 12” (1’) * 25’ * 36’ = 900 cubic feet of storage to obtain 12” average storage Provided sediment volume within Cell #1: Cross sectional area at west end of Cell #1: 22.75 sq. feet Cross sectional area at east end of Cell #1: 27.375 sq. feet Calculation of provided sediment volume in Cell #1: 22.75*36 + (½*36*4.625) = 819 + 83.25 = 902 cubic feet > 900 OKAY Cell #1 contains an average of 12” of sediment storage @ elev. 497.85 Remainder of vault (Cell #2 and Cell #3) have 6” (0.5’) of sediment storage TIR Section 5: Conveyance System Analysis and Design The proposed on-site conveyance improvements will include a catch basins and storm pipe being conveyed to the proposed storm water vault. The design conveyance system will be analyzed using Section 4 of the King County Storm Water Manual. A Backwater analysis is attached to show the adequate capacity of the onsite design. The tail water elevation within the vault, at the 25-year developed flow is 510.59 (per the KCRTS modeling). Verification from the backwater analysis shows the designed storm system is adequate to convey the 25-year event. STORMWATER CONVEYANCE BACKWATER CALCULATION SHEET(1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)BarrelEntranceEntrance Pipe25 yearPipeOutlet InletBarrelBarrelVelocityTWFrictionHGLHeadSegmentQLengthPipe"n"ElevElevAreaVelocityHeadElevLossElevLossCB to CB(cfs)(ft)SizeValue(feet)(feet)(sq. feet)(fps)(feet)(feet)(feet)(feet)(feet)vault-#145.472015"0.012500.85507.401.234.450.31510.590.056510.650.061#14-#104.684515"0.012507.40509.201.233.800.22511.770.126511.890.045#10-#111.195412"0.012509.45510.220.791.510.04512.710.151512.860.007#11-#121.001912"0.012510.22511.500.791.270.02512.910.053512.960.005#10-#19 3.47 50 15" 0.012 509.20 509.70 1.23 2.82 0.12 512.71 0.049 512.76 0.025#19-#18 0.24 24 12" 0.012 509.95 511.61 0.79 0.30 0.00 513.21 0.023 513.24 0.000#19-#7 2.99 153 15" 0.012 509.20 511.23 1.23 2.43 0.09 513.21 0.148 513.36 0.018#7-#8 1.57 24 12" 0.012 513.94 514.42 0.79 1.99 0.06 513.70 0.023 513.72 0.012510.59 is the 25 year water level elevation within vault, see vault modeling(14) (15) (16) (17) (18) (19) (20) (21)Exit Outlet Inlet Approach Bend JunctionHead Control Control Velocity Head Head HWAddRIM ELEVLoss Elev Elev Head Loss Loss Elev6"UPSTREAM (feet) (feet) (feet) (feet) (feet) (feet) (feet)overtopCBvault-#14 0.31 511.01 508.00 0.31 0.31 0.14 511.77512.27512.84OK!#14-#10 0.22 512.16 509.80 0.22 0.22 0.10 512.71513.21513.68OK!#10-#11 0.04 512.91 510.82 0.04 0.04 0.02 512.91513.41513.50OK!#11-#12 0.02 512.99 512.10 0.02 0.02 0.01 512.99513.49513.50OK!#10-#19 0.12 512.91 510.30 0.12 0.12 0.06 513.21513.71514.61OK!#19-#18 0.00 513.24 512.21 0.00 0.00 0.00 513.24513.74514.61OK!#19-#7 0.09 513.47 511.83 0.09 0.09 0.04 513.70514.20517.42OK!#7-#8 0.06 513.79 515.02 0.06 0.06 0.03 515.17515.67517.42OK! STORMWATER CONVEYANCE BACKWATER CALCULATION SHEET(1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13)Barrel Entrance Entrance Pipe 25 year Pipe Outlet Inlet Barrel Barrel Velocity TW Friction HGL HeadSegmentQLengthPipe"n"ElevElevAreaVelocityHeadElevLossElevLossCB to CB(cfs)(ft)SizeValue(feet)(feet)(sq. feet)(fps)(feet)(feet)(feet)(feet)(feet)#7-#61.2810012"0.012511.48512.480.791.620.04514.200.280514.480.008#6-#41.284612"0.012512.48512.940.791.620.04514.630.129514.760.008#4-#51.284512"0.012516.00516.900.791.620.04514.910.126515.030.008#4-#31.2811812"0.012512.94514.120.791.620.04514.910.330515.240.008#3-#2 1.28 24 12" 0.012 514.12 516.00 0.79 1.62 0.04 515.38 0.067 515.45 0.008#14-#15 0.80 59 12" 0.012 507.65 508.54 0.79 1.01 0.02 511.77 0.165 511.93 0.003#15-#16 0.80 24 12" 0.012 508.54 508.78 0.79 1.01 0.02 510.97 0.067 511.04 0.003(14) (15) (16) (17) (18) (19) (20) (21)Exit Outlet Inlet Approach Bend JunctionHead Control Control Velocity Head Head HWAddRIM ELEVLoss Elev Elev Head Loss Loss Elev6"UPSTREAM (feet) (feet) (feet) (feet) (feet) (feet) (feet)overtopCB#7-#6 0.04 514.53 513.08 0.04 0.04 0.02 514.63515.13519.24OK!#6-#4 0.04 514.81 513.54 0.04 0.04 0.02 514.91515.41519.78OK!#4-#5 0.04 515.08 517.50 0.04 0.04 0.02 517.60518.10520.88OK!#4-#3 0.04 515.28 514.72 0.04 0.04 0.02 515.38515.88517.60OK!#3-#2 0.04 515.50 516.60 0.04 0.04 0.02 516.70517.20517.60OK!#14-#15 0.02 511.95 509.14 0.02 0.02 0.01 510.97511.47511.78OK!#15-#16 0.02 511.06 509.38 0.02 0.02 0.01 511.10511.60511.78OK! Developed Basin A(i) C(n)=0.90A(p) C(n)=0.25R/WAccessD/WA(T)Impervious(PGIS)House(PGIS)OtherA(i)PerviousBasinAreassq. ft.sq. ft.sq. ft.sq. ft.sq. ft.AcresSq. ft.Acres2196202572600012000.2298480.233627223770.0538950.09412005020.016980.025664627494750.0734220.08612006700.025300.017368020150.0516650.0484879039031200024000.42304870.7010182410110.028130.0211542124590.0629620.0712265203962838818000.32123700.281418249360.028880.0215230013350.039650.0216190372711538812000.2197380.2218670030480.0736520.0819582030480.0727720.06204950027751360024000.43307250.71Bypass42411850.0040560.09 TIR Section 6: Special Reports and Studies TIR Section 7: Other Permits This project has obtained a State of Washington Department of Ecology NPDES permit; permit is attached to this Section. 1 Do man From:WQWebPortal@ecy.wa.gov Sent:Thursday, September 28, 2017 8:59 AM To:yamahayz450fv@gmail.com Subject:NOI Submitted Electronic Notice of Intent Submitted A Notice of Intent (NOI) was submitted on 9/28/2017 via a wet ink signature. When a NOI is submitted via a wet ink signature, it is considered incomplete until the certification (signature) page is received. It is very important that you print the certification page at the end of the application process, sign it, and mail it to the address included on the page. If you need to reprint the certification page, please follow the steps below. 1. Log back into SecureAccess Washington 2. Click on the "Permit Coverage - Notice of Intent (NOI)" link. 3. Click on the "Search my existing Notice of Intent (NOI) applications" link. 4. Click on the "Reprint Cert" link for the NOI listed below. Please use the information below to find your NOI. Application Id: 16630 Facility Name: Renton 14 Plat Address: 6201 NE 47th Street Renton, WA 98059 County: King If you have any questions please contact us at WQWebPortal@ecy.wa.gov 9/28/2017 WQWebNOI - Public Notice https://secureaccess.wa.gov/ecy/wqwebportal/wqwebnoi/PublicNoticeGenerated.aspx 1/1 Renton 4 LLC, Kevin Murray, PO Box 837 Renton, WA 98057, is seeking coverage under the Washington State Department of Ecology’s Construction Stormwater NPDES and State Waste Discharge General Permit. The proposed project, Renton 14 Plat, is located at 6201 NE 47th Street in Renton in King county. This project involves 4.85 acres of soil disturbance for Residential construction activities. The receiving waterbody is channel. Any persons desiring to present their views to the Washington State Department of Ecology regarding this Application, or interested in Ecology’s action on this Application, may notify Ecology in writing no later than 30 days of the last date of publication of this notice. Ecology reviews public comments and considers whether discharges from this project would cause a measurable change in receiving water quality, and, if so, whether the project is necessary and in the overriding public interest according to Tier II antidegradation requirements under WAC 173-201A-320. Comments can be submitted to: Department of Ecology Attn: Water Quality Program, Construction Stormwater P.O. Box 47696, Olympia, WA 98504-7696 STATE OF WASHINGTON DEPARTMENT OF ECOLOGY PO Box 47600 • Olympia, WA 98504-7600 • 360-407-6000 711 for Washington Relay Service • Persons with a speech disability can call 877-833-6341 November 28, 2017 Kevin Murray Renton 4 LLC PO Box 837 Renton, WA 98057-0837 RE: Coverage under the Construction Stormwater General Permit (CSWGP) Permit number: Site Name: Location: Disturbed Acres: Dear Mr. Murray: WAR305961 Renton 14 Plat 6201 and 6207 NE 4th Street Renton, WA County: King 4.85 The Washington State Department of Ecology (Ecology) received your Notice of Intent for coverage under Ecology's Construction Stormwater General Permit (CSWGP). This is your permit coverage letter. Your permit coverage is effective November 28, 2017. Please retain this permit coverage letter as the official record of permit coverage for your site. Ecology has approved use of digital formats as long as they are easily produced on your construction site. A mobile friendly copy of the CSWGP permit, permit forms, and information related to your permit can be viewed and downloaded here: www.ecy.wa.gov/ecoverage Please contact your Permit Administrator, listed below, if you would like to receive a hard copy of the CSWGP. Please take time to read the entire permit and contact Ecology if you have any questions. Electronic Discharge Monitoring Reports (WQWebDMR) This permit requires that Permittees submit monthly discharge monitoring reports (DMRs) for the full duration of permit coverage (from issuance date to termination). DMRs must be submitted electronically using Ecology's secure online system, WQWebDMR. To sign up for WQWebDMR go to: www.ecy.wa.gov/programs/wq/permits/paris/webdinthtml . If you have questions, contact the portal staff at (360) 407-7097 (Olympia area), or (800) 633-6193/option 3, or email WQWebPortal@ecy.wa.gov. '''"11W:1(1116 Kevin Murray November 28, 2017 Page 2 Appeal Process You have a right to appeal coverage under the general permit to the Pollution Control Hearing Board (PCHB). Appeals must be filed within 30 days of the date of receipt of this letter. Any appeal is limited to the general permit's applicability or non-applicability to a specific discharger. The appeal process is governed by chapter 43.21B RCW and chapter 371-08 WAC. "Date of receipt" is defined in RCW 43.21B.001(2). Ecology Field Inspector Assistance If you have questions regarding stomiwater management at your construction site, please contact Evan Dobrowslci of Ecology's Northwest Regional Office in Bellevue at evan.dobrowslci@ecy.wa.gov, or (425) 649-7276. Questions or Additional Information Ecology is committed to providing assistance. Please review our web page at: www.ecy.wa.gov/programs/wq/stormwater/construction. If you have questions about the construction stormwater general permit, please contact your Permit Administrator, RaChelle Stane at rcla461@ecy.wa.gov or (360) 407-6556. A mobile friendly copy of the CSWGP permit, permit forms, and other information related to your permit (DMRs, Appeal, & Guidance) can be viewed and downloaded here: http://www.ecy.wa.gov/programs/wq/stormwater/construction/ecoverage.html. Sincerely, Bill Moore, Moore, P.E., Manager Program Development Services Section Water Quality Program TIR Section 8: CSWPPP Analysis and Design A Temporary Erosion and Sediment Control Plan (TESCP) implementing Best Management Practices has been included within the utility permit (U16006039) set of plans. The project site is larger than 3 acres, therefore a temporary sediment pond will be required and is shown on the TESCP; sizing and analysis included in this Report. The temporary sediment pond will be utilized during the initial construction of the project. Once the permanent runoff control facility (wet vault) has been installed, this permanent facility will be used for the sediment retention through completion of the project. The temporary sediment faciality can be removed once the permanent facility is operational. Temporary sediment pond sizing shall be per Section D.3.5.2 of the King County Storm Water Manual. The surface area (SA) of the temporary pond will be sized using the developed conditions, 2 year- 15-minute event <Q(2)>. The principle spillway will be sized using the 10-year event <Q(10)>. The emergency spillway will be sized using the existing 100-year event <Q(100)>. The riser within the temporary pond will be checked for overflow capacity using Q(100) to verify overtopping of the emergency spillway. TEMP. SEDIMENT POND SIZING TIR Section 9: Bond Quantities, Facility Summaries, and Declaration of Covenant BOND QUANTITY WORKSHEET CED Permit #:16006039UnitReference #PriceUnitQuantity CostBackfill & compaction-embankmentESC-16.50$ CY583537,927.50Check dams, 4" minus rockESC-2SWDM 5.4.6.380.00$ Each Catch Basin ProtectionESC-335.50$ Each21745.50Crushed surfacing 1 1/4" minusESC-4WSDOT 9-03.9(3)95.00$ CY DitchingESC-59.00$ CY3803,420.00Excavation-bulkESC-62.00$ CY901618,032.00Fence, siltESC-7SWDM 5.4.3.11.50$ LF10741,611.00Fence, Temporary (NGPE)ESC-81.50$ LF Geotextile FabricESC-92.50$ SY350875.00Hay Bale Silt TrapESC-100.50$ Each HydroseedingESC-11SWDM 5.4.2.40.80$ SY2000016,000.00Interceptor Swale / DikeESC-121.00$ LF800800.00Jute 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$ LF801,440.00Plastic 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$ Each13,200.00Sediment pond riser assemblyESC-24SWDM 5.4.5.22,200.00$ Each12,200.00Sediment 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$ HR606,600.00Water truck, dust controlESC-31SWDM 5.4.7140.00$ HR UnitReference #PriceUnitQuantity Cost30.00$ Lin. Feet2908,700.001.25$ S.F.24503,062.50 EROSION/SEDIMENT SUBTOTAL:104,613.50SALES TAX @ 10%10,461.35EROSION/SEDIMENT TOTAL:115,074.85(A)SITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR EROSION & SEDIMENT CONTROLDescription No.(A)6' Temp. FencingTemp. Sediment Pond WRITE-IN-ITEMS Page 1 of 1Ref 8-H Bond Quantity WorksheetSECTION II.a EROSION_CONTROLUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 9/26/2017 CED Permit #:16006039ExistingFuture PublicPrivateRight-of-WayImprovementsImprovements(D) (E)DescriptionNo. Unit PriceUnitQuant.CostQuant.CostQuant.CostQuant.CostGENERAL ITEMS Backfill & Compaction- embankmentGI-16.00$ CY130780.004802,880.00Backfill & Compaction- trenchGI-29.00$ CYClear/Remove Brush, by hand (SY)GI-31.00$ SYBollards - fixedGI-4240.74$ Each2481.48Bollards - removableGI-5452.34$ Each41,809.36Clearing/Grubbing/Tree RemovalGI-610,000.00$ Acre110,000.000.55,000.00Excavation - bulkGI-72.00$ CY15753,150.00Excavation - TrenchGI-85.00$ CYFencing, cedar, 6' highGI-920.00$ LF2755,500.00Fencing, chain link, 4'GI-1038.31$ LFFencing, chain link, vinyl coated, 6' highGI-1120.00$ LFFencing, chain link, gate, vinyl coated, 20' GI-121,400.00$ EachFill & compact - common barrowGI-1325.00$ CYFill & compact - gravel baseGI-1427.00$ CY982,646.00220059,400.00Fill & compact - screened topsoilGI-1539.00$ CYGabion, 12" deep, stone filled mesh GI-1665.00$ SYGabion, 18" deep, stone filled mesh GI-1790.00$ SYGabion, 36" deep, stone filled meshGI-18150.00$ SYGrading, fine, by handGI-192.50$ SYGrading, fine, with graderGI-202.00$ SY23804,760.00Monuments, 3' LongGI-21250.00$ Each3750.00Sensitive Areas SignGI-227.00$ EachSodding, 1" deep, sloped groundGI-238.00$ SYSurveying, line & gradeGI-24850.00$ Day1850.0021,700.001850.00Surveying, lot location/linesGI-251,800.00$ Acre3.255,850.00Topsoil Type A (imported)GI-2628.50$ CYTraffic control crew ( 2 flaggers )GI-27120.00$ HR8960.00Trail, 4" chipped woodGI-288.00$ SYTrail, 4" crushed cinderGI-299.00$ SYTrail, 4" top courseGI-3012.00$ SYConduit, 2"GI-315.00$ LF10625,310.00Wall, retaining, concreteGI-3255.00$ SFWall, rockeryGI-3315.00$ SF88013,200.00SUBTOTAL THIS PAGE:5,236.0084,800.0035,840.84(B)(C)(D)(E)SITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR STREET AND SITE IMPROVEMENTSQuantity Remaining (Bond Reduction) (B)(C)Page 1 of 3Ref 8-H Bond Quantity WorksheetSECTION II.b TRANSPORTATIONUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 1/18/2018 CED Permit #:16006039ExistingFuture PublicPrivateRight-of-WayImprovementsImprovements(D) (E)DescriptionNo. Unit PriceUnitQuant.CostQuant.CostQuant.CostQuant.CostSITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR STREET AND SITE IMPROVEMENTSQuantity Remaining (Bond Reduction) (B)(C)ROAD IMPROVEMENT/PAVEMENT/SURFACINGAC Grinding, 4' wide machine < 1000syRI-130.00$ SYAC Grinding, 4' wide machine 1000-2000syRI-216.00$ SYAC Grinding, 4' wide machine > 2000syRI-310.00$ SYAC Removal/DisposalRI-435.00$ SY39213,720.00Barricade, Type III ( Permanent )RI-556.00$ LF2112.00Guard RailRI-630.00$ LFCurb & Gutter, rolledRI-717.00$ LFCurb & Gutter, verticalRI-812.50$ LF3264,075.00158619,825.001371,712.50Curb and Gutter, demolition and disposalRI-918.00$ LF42756.00Curb, extruded asphaltRI-105.50$ LFCurb, extruded concreteRI-117.00$ LFSawcut, asphalt, 3" depthRI-121.85$ LF326603.10Sawcut, concrete, per 1" depthRI-133.00$ LFSealant, asphaltRI-142.00$ LF358716.00Shoulder, gravel, 4" thickRI-1515.00$ SYSidewalk, 4" thickRI-1638.00$ SY34212,996.0030711,666.00Sidewalk, 4" thick, demolition and disposalRI-1732.00$ SYSidewalk, 5" thickRI-1841.00$ SY20820.001335,453.00Sidewalk, 5" thick, demolition and disposalRI-1940.00$ SYSign, Handicap RI-2085.00$ EachStriping, per stallRI-217.00$ EachStriping, thermoplastic, ( for crosswalk )RI-223.00$ SFStriping, 4" reflectorized lineRI-230.50$ LFAdditional 2.5" Crushed SurfacingRI-243.60$ SYHMA 1/2" Overlay 1.5" RI-2514.00$ SYHMA 1/2" Overlay 2"RI-2618.00$ SYHMA Road, 2", 4" rock, First 2500 SYRI-2728.00$ SYHMA Road, 2", 4" rock, Qty. over 2500SYRI-2821.00$ SYHMA Road, 4", 6" rock, First 2500 SYRI-2945.00$ SY39217,640.00211495,130.0028812,960.00HMA Road, 4", 6" rock, Qty. over 2500 SYRI-3037.00$ SYHMA Road, 4", 4.5" ATBRI-3138.00$ SYGravel Road, 4" rock, First 2500 SYRI-3215.00$ SY2353,525.00Gravel Road, 4" rock, Qty. over 2500 SYRI-3310.00$ SYThickened EdgeRI-348.60$ LFSUBTOTAL THIS PAGE:51,326.10132,186.0018,197.50(B)(C)(D)(E)Page 2 of 3Ref 8-H Bond Quantity WorksheetSECTION II.b TRANSPORTATIONUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 1/18/2018 CED Permit #:16006039ExistingFuture PublicPrivateRight-of-WayImprovementsImprovements(D) (E)DescriptionNo. Unit PriceUnitQuant.CostQuant.CostQuant.CostQuant.CostSITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR STREET AND SITE IMPROVEMENTSQuantity Remaining (Bond Reduction) (B)(C)PARKING LOT SURFACINGNo.2" AC, 2" top course rock & 4" borrowPL-121.00$ SY2" AC, 1.5" top course & 2.5" base coursePL-228.00$ SY4" select borrowPL-35.00$ SY1.5" top course rock & 2.5" base coursePL-414.00$ SYSUBTOTAL PARKING LOT SURFACING:(B)(C)(D)(E)LANDSCAPING & VEGETATIONNo.Street TreesLA-1225.00$ EACH102,250.00296,525.00Median LandscapingLA-2Right-of-Way LandscapingLA-34.25$ SQ. FT.15356,523.75425018,062.50Wetland LandscapingLA-4SUBTOTAL LANDSCAPING & VEGETATION:8,773.7524,587.50(B)(C)(D)(E)TRAFFIC & LIGHTINGNo.SignsTR-1350.00$ 196,650.00Street Light System ( # of Poles)TR-24,800.00$ 14,800.001152,800.00Traffic SignalTR-3Traffic Signal ModificationTR-4SUBTOTAL TRAFFIC & LIGHTING:4,800.0059,450.00(B)(C)(D)(E)WRITE-IN-ITEMSSUBTOTAL WRITE-IN ITEMS:STREET AND SITE IMPROVEMENTS SUBTOTAL:70,135.85301,023.5054,038.34SALES TAX @ 10%7,013.5930,102.355,403.83STREET AND SITE IMPROVEMENTS TOTAL:77,149.44331,125.8559,442.17(B)(C)(D)(E)Page 3 of 3Ref 8-H Bond Quantity WorksheetSECTION II.b TRANSPORTATIONUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 1/18/2018 CED Permit #:16006039ExistingFuture PublicPrivateRight-of-WayImprovementsImprovements(D) (E)DescriptionNo. Unit PriceUnitQuant.CostQuant.CostQuant.CostQuant.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/DD-126.00$ SY2346,084.00* (CBs include frame and lid)BeehiveD-290.00$ EachThrough-curb Inlet FrameworkD-3400.00$ EachCB Type ID-41,500.00$ Each11,500.001015,000.00710,500.00CB Type ILD-51,750.00$ EachCB Type II, 48" diameterD-62,300.00$ Each49,200.00 for additional depth over 4' D-7480.00$ FT83,840.00CB Type II, 54" diameterD-82,500.00$ Each for additional depth over 4'D-9495.00$ FTCB Type II, 60" diameterD-102,800.00$ Each for additional depth over 4'D-11600.00$ FTCB Type II, 72" diameterD-126,000.00$ Each for additional depth over 4'D-13850.00$ FTCB Type II, 96" diameterD-1414,000.00$ Each for additional depth over 4'D-15925.00$ FTTrash Rack, 12"D-16350.00$ EachTrash Rack, 15"D-17410.00$ EachTrash Rack, 18"D-18480.00$ EachTrash Rack, 21"D-19550.00$ EachCleanout, PVC, 4"D-20150.00$ EachCleanout, PVC, 6"D-21170.00$ Each111,870.00Cleanout, PVC, 8"D-22200.00$ EachCulvert, PVC, 4" D-2310.00$ LFCulvert, PVC, 6" D-2413.00$ LF82610,738.00Culvert, PVC, 8" D-2515.00$ LFCulvert, PVC, 12" D-2623.00$ LFCulvert, PVC, 15" D-2735.00$ LFCulvert, PVC, 18" D-2841.00$ LFCulvert, PVC, 24"D-2956.00$ LFCulvert, PVC, 30" D-3078.00$ LFCulvert, PVC, 36" D-31130.00$ LFCulvert, CMP, 8"D-3219.00$ LFCulvert, CMP, 12"D-3329.00$ LFSUBTOTAL THIS PAGE:1,500.0028,040.0029,192.00(B)(C)(D)(E)Quantity Remaining (Bond Reduction) (B)(C)SITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR DRAINAGE AND STORMWATER FACILITIESPage 1 of 5Ref 8-H Bond Quantity WorksheetSECTION II.c DRAINAGEUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 1/18/2018 CED Permit #:16006039ExistingFuture PublicPrivateRight-of-WayImprovementsImprovements(D) (E)DescriptionNo. Unit PriceUnitQuant.CostQuant.CostQuant.CostQuant.CostQuantity Remaining (Bond Reduction) (B)(C)SITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR DRAINAGE AND STORMWATER FACILITIESDRAINAGE (Continued)Culvert, CMP, 15"D-3435.00$ LFCulvert, CMP, 18"D-3541.00$ LFCulvert, CMP, 24"D-3656.00$ LFCulvert, CMP, 30"D-3778.00$ LFCulvert, CMP, 36"D-38130.00$ LFCulvert, CMP, 48"D-39190.00$ LFCulvert, CMP, 60"D-40270.00$ LFCulvert, CMP, 72"D-41350.00$ LFCulvert, Concrete, 8"D-4242.00$ LFCulvert, Concrete, 12"D-4348.00$ LFCulvert, Concrete, 15"D-4478.00$ LFCulvert, Concrete, 18"D-4548.00$ LFCulvert, Concrete, 24"D-4678.00$ LFCulvert, Concrete, 30"D-47125.00$ LFCulvert, Concrete, 36"D-48150.00$ LFCulvert, Concrete, 42"D-49175.00$ LFCulvert, Concrete, 48"D-50205.00$ LFCulvert, CPE Triple Wall, 6" D-5114.00$ LFCulvert, CPE Triple Wall, 8" D-5216.00$ LFCulvert, CPE Triple Wall, 12" D-5324.00$ LFCulvert, CPE Triple Wall, 15" D-5435.00$ LFCulvert, CPE Triple Wall, 18" D-5541.00$ LFCulvert, CPE Triple Wall, 24" D-5656.00$ LFCulvert, CPE Triple Wall, 30" D-5778.00$ LFCulvert, CPE Triple Wall, 36" D-58130.00$ LFCulvert, LCPE, 6"D-5960.00$ LFCulvert, LCPE, 8"D-6072.00$ LFCulvert, LCPE, 12"D-6184.00$ LF19616,464.0049941,916.0021818,312.00Culvert, LCPE, 15"D-6296.00$ LF26625,536.00Culvert, LCPE, 18"D-63108.00$ LFCulvert, LCPE, 24"D-64120.00$ LFCulvert, LCPE, 30"D-65132.00$ LFCulvert, LCPE, 36"D-66144.00$ LFCulvert, LCPE, 48"D-67156.00$ LFCulvert, LCPE, 54"D-68168.00$ LFSUBTOTAL THIS PAGE:16,464.0067,452.0018,312.00(B)(C)(D)(E)Page 2 of 5Ref 8-H Bond Quantity WorksheetSECTION II.c DRAINAGEUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 1/18/2018 CED Permit #:16006039ExistingFuture PublicPrivateRight-of-WayImprovementsImprovements(D) (E)DescriptionNo. Unit PriceUnitQuant.CostQuant.CostQuant.CostQuant.CostQuantity Remaining (Bond Reduction) (B)(C)SITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR DRAINAGE AND STORMWATER FACILITIESDRAINAGE (Continued)Culvert, LCPE, 60"D-69180.00$ LFCulvert, LCPE, 72"D-70192.00$ LFCulvert, HDPE, 6"D-7142.00$ LFCulvert, HDPE, 8"D-7242.00$ LFCulvert, HDPE, 12"D-7374.00$ LFCulvert, HDPE, 15"D-74106.00$ LFCulvert, HDPE, 18"D-75138.00$ LFCulvert, HDPE, 24"D-76221.00$ LFCulvert, HDPE, 30"D-77276.00$ LFCulvert, HDPE, 36"D-78331.00$ LFCulvert, HDPE, 48"D-79386.00$ LFCulvert, HDPE, 54"D-80441.00$ LFCulvert, HDPE, 60"D-81496.00$ LFCulvert, HDPE, 72"D-82551.00$ LFPipe, Polypropylene, 6"D-8384.00$ LFPipe, Polypropylene, 8"D-8489.00$ LFPipe, Polypropylene, 12"D-8595.00$ LFPipe, Polypropylene, 15"D-86100.00$ LFPipe, Polypropylene, 18"D-87106.00$ LFPipe, Polypropylene, 24"D-88111.00$ LFPipe, Polypropylene, 30"D-89119.00$ LFPipe, Polypropylene, 36"D-90154.00$ LFPipe, Polypropylene, 48"D-91226.00$ LFPipe, Polypropylene, 54"D-92332.00$ LFPipe, Polypropylene, 60"D-93439.00$ LFPipe, Polypropylene, 72"D-94545.00$ LFCulvert, DI, 6"D-9561.00$ LFCulvert, DI, 8"D-9684.00$ LFCulvert, DI, 12"D-97106.00$ LFCulvert, DI, 15"D-98129.00$ LFCulvert, DI, 18"D-99152.00$ LFCulvert, DI, 24"D-100175.00$ LFCulvert, DI, 30"D-101198.00$ LFCulvert, DI, 36"D-102220.00$ LFCulvert, DI, 48"D-103243.00$ LFCulvert, DI, 54"D-104266.00$ LFCulvert, DI, 60"D-105289.00$ LFCulvert, DI, 72"D-106311.00$ LFSUBTOTAL THIS PAGE:(B)(C)(D)(E)Page 3 of 5Ref 8-H Bond Quantity WorksheetSECTION II.c DRAINAGEUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 1/18/2018 CED Permit #:16006039ExistingFuture PublicPrivateRight-of-WayImprovementsImprovements(D) (E)DescriptionNo. Unit PriceUnitQuant.CostQuant.CostQuant.CostQuant.CostQuantity Remaining (Bond Reduction) (B)(C)SITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR DRAINAGE AND STORMWATER FACILITIESSpecialty Drainage ItemsDitching SD-19.50$ CY6075,766.50Flow Dispersal Trench (1,436 base+)SD-328.00$ LF French Drain (3' depth)SD-426.00$ LFGeotextile, laid in trench, polypropyleneSD-53.00$ SYMid-tank Access Riser, 48" dia, 6' deepSD-62,000.00$ EachPond Overflow SpillwaySD-716.00$ SYRestrictor/Oil Separator, 12"SD-81,150.00$ Each11,150.00Restrictor/Oil Separator, 15"SD-91,350.00$ EachRestrictor/Oil Separator, 18"SD-101,700.00$ EachRiprap, placedSD-1142.00$ CY6252.00Tank End Reducer (36" diameter)SD-121,200.00$ EachInfiltration pond testingSD-13125.00$ HRPermeable PavementSD-14Permeable Concrete SidewalkSD-15Culvert, Box __ ft x __ ftSD-16SUBTOTAL SPECIALTY DRAINAGE ITEMS:7,168.50(B)(C)(D)(E)STORMWATER FACILITIES (Include Flow Control and Water Quality Facility Summary Sheet and Sketch)Detention PondSF-1Each Detention TankSF-2Each Detention VaultSF-3Each Infiltration PondSF-4Each Infiltration TankSF-5Each Infiltration VaultSF-6Each Infiltration TrenchesSF-7Each Basic Biofiltration SwaleSF-8Each Wet Biofiltration SwaleSF-9Each WetpondSF-10Each WetvaultSF-112.75$ Each 80200220,550.00Sand FilterSF-12Each Sand Filter VaultSF-13Each Linear Sand FilterSF-14Each Proprietary FacilitySF-15Each Bioretention FacilitySF-16Each SUBTOTAL STORMWATER FACILITIES:220,550.00(B)(C)(D)(E)Page 4 of 5Ref 8-H Bond Quantity WorksheetSECTION II.c DRAINAGEUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 1/18/2018 CED Permit #:16006039ExistingFuture PublicPrivateRight-of-WayImprovementsImprovements(D) (E)DescriptionNo. Unit PriceUnitQuant.CostQuant.CostQuant.CostQuant.CostQuantity Remaining (Bond Reduction) (B)(C)SITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR DRAINAGE AND STORMWATER FACILITIESWRITE-IN-ITEMS (INCLUDE ON-SITE BMPs)Yard DrainsWI-1750.00$ 43,000.00Detention Tank tract access roadWI-21,500.00$ 11,500.00WI-3WI-4WI-5WI-6WI-7WI-8WI-9WI-10WI-11WI-12WI-13WI-14WI-15SUBTOTAL WRITE-IN ITEMS:4,500.00DRAINAGE AND STORMWATER FACILITIES SUBTOTAL:17,964.0095,492.00279,722.50SALES TAX @ 10%1,796.409,549.2027,972.25DRAINAGE AND STORMWATER FACILITIES TOTAL:19,760.40105,041.20307,694.75(B) (C) (D) (E)Page 5 of 5Ref 8-H Bond Quantity WorksheetSECTION II.c DRAINAGEUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 1/18/2018 CED Permit #:16006039ExistingFuture PublicPrivateRight-of-WayImprovementsImprovements(D) (E)DescriptionNo. Unit PriceUnitQuant.CostQuant.CostQuant.CostQuant.CostConnection to Existing WatermainW-12,000.00$ EachDuctile Iron Watermain, CL 52, 4 Inch DiameterW-250.00$ LFDuctile Iron Watermain, CL 52, 6 Inch DiameterW-356.00$ LFDuctile Iron Watermain, CL 52, 8 Inch DiameterW-460.00$ LFDuctile Iron Watermain, CL 52, 10 Inch DiameterW-570.00$ LFDuctile Iron Watermain, CL 52, 12 Inch DiameterW-680.00$ LFGate Valve, 4 inch DiameterW-7500.00$ EachGate Valve, 6 inch DiameterW-8700.00$ EachGate Valve, 8 Inch DiameterW-9800.00$ EachGate Valve, 10 Inch DiameterW-101,000.00$ EachGate Valve, 12 Inch DiameterW-111,200.00$ EachFire Hydrant AssemblyW-124,000.00$ EachPermanent Blow-Off AssemblyW-131,800.00$ EachAir-Vac Assembly, 2-Inch DiameterW-142,000.00$ EachAir-Vac Assembly, 1-Inch DiameterW-151,500.00$ EachCompound Meter Assembly 3-inch DiameterW-168,000.00$ EachCompound Meter Assembly 4-inch DiameterW-179,000.00$ EachCompound Meter Assembly 6-inch DiameterW-1810,000.00$ EachPressure Reducing Valve Station 8-inch to 10-inchW-1920,000.00$ EachWATER SUBTOTAL:SALES TAX @ 10%WATER TOTAL:(B) (C) (D) (E)SITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR WATERQuantity Remaining (Bond Reduction) (B)(C)Page 1 of 1Ref 8-H Bond Quantity WorksheetSECTION II.d WATERUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 9/26/2017 CED Permit #:16006039ExistingFuture PublicPrivateRight-of-WayImprovementsImprovements(D) (E)DescriptionNo. Unit PriceUnitQuant.CostQuant.CostQuant.CostQuant.CostClean OutsSS-11,000.00$ Each1515,000.00Grease Interceptor, 500 gallonSS-28,000.00$ EachGrease Interceptor, 1000 gallonSS-310,000.00$ EachGrease Interceptor, 1500 gallonSS-415,000.00$ EachSide Sewer Pipe, PVC. 4 Inch DiameterSS-580.00$ LFSide Sewer Pipe, PVC. 6 Inch DiameterSS-695.00$ LF73269,540.00Sewer Pipe, PVC, 8 inch DiameterSS-7105.00$ LF101,050.0084889,040.00Sewer Pipe, PVC, 12 Inch DiameterSS-8120.00$ LFSewer Pipe, DI, 8 inch DiameterSS-9115.00$ LFSewer Pipe, DI, 12 Inch DiameterSS-10130.00$ LFManhole, 48 Inch DiameterSS-116,000.00$ Each742,000.00Manhole, 54 Inch DiameterSS-136,500.00$ Each16,500.00Manhole, 60 Inch DiameterSS-157,500.00$ EachManhole, 72 Inch DiameterSS-178,500.00$ EachManhole, 96 Inch DiameterSS-1914,000.00$ EachPipe, C-900, 12 Inch DiameterSS-21180.00$ LFOutside DropSS-241,500.00$ LSInside DropSS-251,000.00$ LS16" SleeveSS-2685.00$ L.F.201,700.00Lift Station (Entire System)SS-27LSSANITARY SEWER SUBTOTAL:1,050.00139,240.0084,540.00SALES TAX @ 10%105.0013,924.008,454.00SANITARY SEWER TOTAL:1,155.00153,164.0092,994.00(B) (C) (D) (E)SITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR SANITARY SEWERQuantity Remaining (Bond Reduction) (B)(C)Page 1 of 1Ref 8-H Bond Quantity WorksheetSECTION II.e SANITARY SEWERUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 9/26/2017 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)78,304.44$ Future Public Improvements Subtotal(c)484,289.85$ Stormwater & Drainage Facilities (Public & Private) Subtotal(d)(d)432,496.35$ (e)(f)Site RestorationCivil Construction PermitMaintenance Bond199,018.13$ 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)115,074.85$ 78,304.44$ 549,953.00$ 115,074.85$ -$ 432,496.35$ -$ 665,027.85$ P (a) x 100%SITE IMPROVEMENT BOND QUANTITY WORKSHEET BOND CALCULATIONS1/15/2018Darrell L. Offe, Jr.27460Offe Engineers, PLLCR((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)425-260-3412darrell.offe@comcast.netRenton 14 Plat16-0000786201 NE 4th Street142305-9070 & 9064FOR CONSTRUCTION1600603913932 SE 159th Place, Renton, WA 98058Page 1 of 1Ref 8-H Bond Quantity WorksheetSECTION III. BOND WORKSHEETUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 1/18/2018 DECLARATION OF COVENANT Page 1 of 3 Return Address: City Clerk’s Office City of Renton 1055 S Grady Way Renton, WA 98057 DECLARATION OF COVENANT AND EASEMENT FOR INSPECTION AND MAINTENANCE OF DRAINAGE FACILITIES AND ON-SITE BMPS Grantor: Grantee: City of Renton Legal Description: Assessor's Tax Parcel ID#: IN CONSIDERATION of the approved City of Renton (check one of the following) residential building permit, commercial building permit, clearing and grading permit, subdivision permit, or short subdivision permit for application file No. LUA/SWP_______________________ relating to the real property ("Property") described above, the Grantor(s), the owner(s) in fee of that Property, hereby covenants(covenant) with the City of Renton, a political subdivision of the state of Washington, that he/she(they) will observe, consent to, and abide by the conditions and obligations set forth and described in Paragraphs 1 through 9 below with regard to the Property, and hereby grants(grant) an easement as described in Paragraphs 2 and 3. Grantor(s) hereby grants(grant), covenants(covenant), and agrees(agree) as follows: 1. The Grantor(s) or his/her(their) successors in interest and assigns ("Owners ") shall at their own cost, operate, maintain, and keep in good repair, the Property's drainage facilities constructed as required in the approved construction plans and specifications __________ on file with the City of Renton and submitted to the City of Renton for the review and approval of permit(s) _____________________________. The property's drainage facilities are shown and/or listed on Exhibit A. The property’s drainage facilities shall be maintained in compliance with the operation and maintenance schedule included and attached herein as Exhibit B. Drainage facilities include pipes, channels, flow control facilities, water quality facilities, on-site best management practices (BMPs) and other engineered structures designed to manage and/or treat stormwater on the Property. On-site BMPs include dispersion and infiltration devices, bioretention, permeable pavements, rainwater harvesting systems, tree retention credit, reduced impervious surface footprint, vegetated roofs and other measures designed to mimic pre-developed hydrology and minimize stormwater runoff on the Property. 2. City of Renton shall have the right to ingress and egress over those portions of the Property necessary to perform inspections of the stormwater facilities and BMPs and conduct maintenance activities specified in this Declaration of Covenant and in accordance with the Renton Municipal Code. City of Renton shall provide at least 30 days written notice to the Owners that entry on the Property is RENTON 14, LLC X LUA16-000078 U16-006039 142305-9070 & 9064 A PORTION OF THE NORTH HALF OF THE NORTHEAST QUARTER OF THE NORTHWEST QUARTER OF SECTION 14, TOWNSHIP 23 NORTH, RANGE 5 EAST, W.M, IN KING COUNTY, WAHINGTON Page 2 of 3 planned for the inspection of drainage facilities. After the 30 days, the Owners shall allow the City of Renton to enter for the sole purpose of inspecting drainage facilities. In lieu of inspection by the City, the Owners may elect to engage a licensed civil engineer registered in the state of Washington who has expertise in drainage to inspect the drainage facilities and provide a written report describing their condition. If the engineer option is chosen, the Owners shall provide written notice to the City of Renton within fifteen days of receiving the City’s notice of inspection. Within 30 days of giving this notice, the Owners, or engineer on behalf of the Owners, shall provide the engineer’s report to the City of Renton. If the report is not provided in a timely manner as specified above, the City of Renton may inspect the drainage facilities without further notice. 3. If City of Renton determines from its inspection, or from an engineer’s report provided in accordance with Paragraph 2, that maintenance, repair, restoration, and/or mitigation work is required to be done to any of the drainage facilities, City of Renton shall notify the Owners of the specific maintenance, repair, restoration, and/or mitigation work (Work) required pursuant to the Renton Municipal Code. The City shall also set a reasonable deadline for the Owners to complete the Work, or to provide an engineer’s report that verifies completion of the Work. After the deadline has passed, the Owners shall allow the City access to re-inspect the drainage facilities unless an engineer’s report has been provided verifying completion of the Work. If the Work is not completed within the time frame set by the City, the City may initiate an enforcement action and/or perform the required maintenance, repair, restoration, and/or mitigation work and hereby is given access to the Property for such purposes. Written notice will be sent to the Owners stating the City’s intention to perform such work. This work will not commence until at least seven (7) days after such notice is mailed. If, within the sole discretion of the City, there exists an imminent or present danger, the seven (7) day notice period will be waived and maintenance and/or repair work will begin immediately. 4. The Owners shall assume all responsibility for the cost of any maintenance, repair work, or any measures taken by the City to address conditions as described in Paragraph 3. Such responsibility shall include reimbursement to the City within thirty (30) days of the receipt of the invoice for any such work performed. Overdue payments will require payment of interest at the maximum legal rate allowed by RCW 19.52.020 (currently twelve percent (12%)). If the City initiates legal action to enforce this agreement, the prevailing party in such action is entitled to recover reasonable litigation costs and attorney’s fees. 5. The Owners are required to obtain written approval from City of Renton prior to filling, piping, cutting, or removing vegetation (except in routine landscape maintenance) in open vegetated stormwater facilities (such as swales, channels, ditches, ponds, etc.), or performing any alterations or modifications to the drainage facilities referenced in this Declaration of Covenant. 6. Any notice or consent required to be given or otherwise provided for by the provisions of this Agreement shall be effective upon personal delivery, or three (3) days after mailing by Certified Mail, return receipt requested. 7. With regard to the matters addressed herein, this agreement constitutes the entire agreement between the parties, and supersedes all prior discussions, negotiations, and all agreements whatsoever whether oral or written. 8. This Declaration of Covenant is intended to protect the value and desirability and promote efficient and effective management of surface water drainage of the real property described above, and shall inure to the benefit of all the citizens of the City of Renton and its successors and assigns. This Page 3 of 3 Declaration of Covenant shall run with the land and be binding upon Grantor(s), and Grantor's(s') successors in interest, and assigns. 9. This Declaration of Covenant may be terminated by execution of a written agreement by the Owners and the City that is recorded by King County in its real property records. IN WITNESS WHEREOF, this Declaration of Covenant for the Inspection and Maintenance of Drainage Facilities is executed this _____ day of ____________________, 20_____. GRANTOR, owner of the Property GRANTOR, owner of the Property STATE OF WASHINGTON ) COUNTY OF KING )ss. On this day personally appeared before me: , to me known to be the individual(s) described in and who executed the within and foregoing instrument and acknowledged that they signed the same as their free and voluntary act and deed, for the uses and purposes therein stated. Given under my hand and official seal this _____ day of ____________________, 20_____. Printed name Notary Public in and for the State of Washington, residing at My appointment expires TIR Section 10: Operations and Maintenance Manual The permanent storm water detention/water quality facility (wet vault) will be maintained by the City of Renton. Tract A, storm water tract, will be owned by the HOA. The private storm stubs and on-lot BMP’s will be maintained by the individual property owners. The maintenance and operations for the private systems has been included within TIR Section 9.