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HomeMy WebLinkAboutPRE23-000270_ENG CommentsDEPARTMENT OF COMMUNITY AND ECONOMIC DEVELOPMENT M E M O R A N D U M   DATE: September 14, 2023     TO: Clark Close, Planner     FROM: Sam Morman, Civil Engineer     SUBJECT: Riu Cottages 13012 80th Ave S PRE23-000270      NOTE: The applicant is cautioned that information contained in this summary is preliminary and non-binding and may be subject to modification and/or concurrence by official City decision-makers. Review comments may also need to be revised based on site planning and other design changes required by City staff or made by the applicant. I have completed a preliminary review for the above-referenced proposal located at parcel(s) 2144800325. The following comments are based on the pre-application submittal made to the City of Renton by the applicant. Water The project is within the City of Renton’s water service area in the West Hill 495 Pressure Zone. The static water pressure is approximately 93 psi at ground elevation of 280 feet. There is an existing 6-inch water main located in 80th Ave S that can deliver a maximum flow capacity of 1,000 GPM (see water plan No. W-036804). There is an existing 8-inch water main located in S 130th St that can deliver a maximum flow capacity of 2,500 GPM (see water plan No. W-282901). Based on the review of project information submitted for the pre-application meeting, Renton Regional Fire Authority has determined that the preliminary fire flow demand for single-family homes is 1,000 gpm minimum for dwellings up to 3,600 square feet (including garage and basements).  If the dwelling exceeds 3,600 square feet, a minimum of 1,500 gpm fire flow would be required. Based on the information provided with the pre-application submittal documents, Renton Regional Fire Authority (RRFA) has determined that the preliminary fire flow demand for the development ranges from 1,000 gpm to 1,500 gpm depending on the size of the buildings. The following developer’s installed water main improvements will be required to provide domestic and fire protection service to the development including but not limited to the items that follow. Installation of an 8-inch water main within the interior access road/drive lane depending on the final layout of the development.  The existing 6-inch water main in 80th Ave S must be replaced with a new 8-inch water main if it is impacted by the installation of new off-site improvements and related utilities and landscaping. Installation of additional fire hydrant(s) as required by RRFA. A 15-foot-wide public water easement is required for any public water main, hydrants and water meters located outside City Right-of-Way. Installation of a separate water service (minimum 1-inch) and meter for each new cottage. The sizing of the meter shall be in accordance with the most recent edition of the Uniform Plumbing Code. Installation of the service and water meter shall be done by City forces if the meter is connected to an existing water main, a separate water permit is required. A pressure reducing valve is required downstream of the any meters where the water pressure exceeds 80 psi. Installation of a landscape irrigation meter with a backflow prevention assembly (DCVA) if applicable. Civil plans for the water main improvements will be required and must be prepared by a professional engineer registered in the State of Washington. Please refer to City of Renton General Design and Construction Standards for Water Main Extensions as shown in Appendix K of the City’s 2019 Water System Plan. Adequate horizontal and vertical separations between the new water main and other utilities (storm sewer pipes and vaults, sanitary sewer, power, gas, electrical) shall be provided for the operation and maintenance of the water main. Retaining walls, rockeries or similar structures cannot be installed over the water main unless the water main is installed inside a steel casing. A conceptual utility plan will be required as part of the land use application for the subject development. The development is subject to applicable water system development charges (SDC’s) and meter installation fees based on the number and size of the meters for domestic uses and for fire sprinkler use. The development is also subject to fees for water connections, cut and caps, and purity tests. Current fees can be found in the 2023 Development Fees Document on the City’s website. Fees will be charged based on the rate at the time of construction permit issuance. The SDC fee for water is based on the size of the new domestic water to serve the project. The current water fee is $4,850.00 per 1-inch meter. Water service installation charges for each proposed domestic water service is applicable. Water Service installation is $2,875.00 per 1-inch service line, Drop-in meter fee is $400 per ¾-inch meter and $460.00 per 1-inch meter. A credit will be applied to the existing services if abandoned. The full fee schedule can be found at: https://edocs.rentonwa.gov/Documents/DocView.aspx?id=10067864&dbid=1&repo=CityofRenton Sanitary Sewer The project is within the City of Renton’s sanitary sewer service area. There is an 8-inch gravity wastewater main located in 80th Ave S (see record drawing S-28290A). There is an 8-inch gravity wastewater main located in S 130th St (see record drawing S-28290C). An 8-inch sewer main extension to serve the proposed cottages will be required. A 15-foot-wide public sewer easement is required for any public sewer main located outside City Right of Way. Individual sewer stubs from the sewer main and individual side sewers are required for each lot. All new sewer stubs shall conform to the standards in RMC 4-6-040 and City of Renton Standard Details. A conceptual utility plan will be required as part of the land use application for the subject development. The development is subject to a wastewater system development charge (SDC) fee. SDC fee for sewer is based on the size of the new domestic water to serve the project. Current fees can be found in the 2023 Development Fees Document on the City’s website. Fees will be charged based on the rate at the time of construction permit issuance. The current sewer SDC fee is $3,650.00 per 1-inch meter. Final determination of applicable fees will be made after the water meter size has been determined. The full fee schedule can be found at: https://edocs.rentonwa.gov/Documents/DocView.aspx?id=10067864&dbid=1&repo=CityofRenton Surface Water There is an existing stormwater ditch located in 80th Ave S that connects to a catch basin located at the southwest corner of the parcel. Any new on or off-site drainage systems must be designed in accordance with Chapter 4 of the 2022 RSWDM. Critical areas on site that may affect stormwater review include regulated (steep) slopes. Drainage plans and a drainage report complying with the adopted 2022 Renton Surface Water Design Manual will be required. Refer to Figure 1.1.2.A – Flow Chart of the 2022 Renton Surface Water Design Manual (RSWDM) to determine what type of drainage review is required for this site. The site falls within the Flow Control Duration Standard Matching Forested Site Conditions. The site falls within the West Lake Washington – Seattle South drainage basin and West Hill sub basin. The current Surface Water Standard Plans shall be used in all drainage plan submittals. The current City of Renton Standard Details are available online in the City of Renton website https://edocs.rentonwa.gov/Documents/Browse.aspx?id=990403&dbid=0&repo=CityofRenton If the new plus replaced pollution generating impervious surface exceeds 5,000 SF, the applicant will be required to provide basic water quality treatment. Any proposed detention and/or water quality vault shall be designed in accordance with the RSWDM that is current at the time of civil construction permit application. Separate structural plans will be required to be submitted for review and approval under a separate building permit for the detention and/or water quality vault. Appropriate on-site BMPs satisfying Core Requirement #9 will be required to help mitigate the new runoff created by this development to the maximum extent feasible. On-site BMPs shall be evaluated as described in Section C.1.3 of the 2022 RSWDM. A preliminary drainage plan, including the application of on-site BMPs, shall be included with the land use application, as applicable to the project. The final drainage plan and drainage report must be submitted with the utility construction permit application. A geotechnical soils report for the site is required per the 2022 Renton Surface Water Design Manual Section C.1.3. Information on the water table and soil permeability (measured infiltration rates), with recommendations of appropriate on-site BMPs per Core Requirement #9 and Appendix C shall be included in the report. The report should also include information concerning the soils, geology, drainage patterns and vegetation present shall be presented in order to evaluate the drainage, erosion control and slope stability for site development of the proposed plat. The applicant must demonstrate the development will not result in soil erosion and sedimentation, landslide, slippage, or excess surface water runoff. Erosion control measures to meet the City requirements shall be provided. The development falls within the R-8 zone which has a maximum impervious surface area of 65% per lot, and maximum building coverage of 50% per lot. The development is subject to a surface water system development charge (SDC) fees. Fees will be charged based on the rate at the time of construction permit issuance. The current SDC fee for a single family residence is $2,300 per lot. The full fee schedule can be found at: https://edocs.rentonwa.gov/Documents/DocView.aspx?id=10067864&dbid=1&repo=CityofRenton Transportation Per City code 4-6-060 frontage improvements are required for new construction in excess of $175,000. The proposed project fronts 80th Ave S to the west, S 130th St to the north, and private property on all other sides. 80th Ave S is classified as a Residential Access street. Existing ROW width is 60 feet per the King County Assessors Map. Existing improvements include a paved roadway of approximately 22 feet with the remainder unimproved. To meet the City’s complete street standards for Residential Access streets, minimum ROW is 53 feet. Per City code 4-6-060, minimum half street improvements shall include a pavement width of 26 feet (13 feet from centerline), a 0.5 foot curb, an 8 foot planting strip, a 5 foot sidewalk, street trees and storm drainage improvements. No ROW dedication is anticipated pending final survey. S 130th St is classified as a Residential Access street. Existing ROW width is 60 feet per the King County Assessors Map. Existing improvements include a paved roadway of approximately 22 feet with the remainder unimproved. To meet the City’s complete street standards for Residential Access streets, minimum ROW is 53 feet. Per City code 4-6-060, minimum half street improvements shall include a pavement width of 26 feet (13 feet from centerline), a 0.5 foot curb, an 8 foot planting strip, a 5 foot sidewalk, street trees and storm drainage improvements. No ROW dedication is anticipated pending final survey. A unit lot drive may serve as access to the site. Unit lot drives shall have a minimum paved roadway width of sixteen feet (16’) however, the Fire Department may require the paved roadway to be up to twenty feet (20’), with 0.5’ curbs, and an eight foot (8’) wide landscaping strip and five foot (5’) wide sidewalk along one side of the drive. Each unit lot drive can serve as access for up to nine (9) lots. Refer to RMC 4-6-060.K for further detail. Undergrounding of all existing utilities is required on all frontages per RMC 4-6-090. Street lighting and street trees are required to be installed by the developer and must meet current City standards. Lighting and Photometric plans are required to be submitted with the land use application and will be reviewed during the construction utility permit review. Paving and trench restoration within the City of Renton right of way shall comply with the City’s Trench Restoration and Street Overlay Requirements. The development is subject to transportation impact fees. Fees will be charged based on the rate at the time of building permit issuance. The 2023 transportation impact fee is $12,208.54 per single family home. The full fee schedule can be found at: https://edocs.rentonwa.gov/Documents/DocView.aspx?id=10067864&dbid=1&repo=CityofRenton General Comments If frontage improvements are required, all existing and proposed utility lines (i.e. electrical, phone, and cable services, etc.) along property frontage or within the site must be underground as outlined in RMC 4-6-090 – UTILITY LINES - UNDERGROUND INSTALLATION. The construction of these franchise utilities must be inspected and approved by a City of Renton inspector. Adequate separation between utilities as well as other features shall be provided in accordance with code requirements. 7-ft minimum horizontal and 1-ft vertical separation between storm and other utilities is required with the exception of water lines which require 10-ft horizontal and 1.5-ft vertical. The stormwater line should be minimum 5 feet away from any other structure or wall or building. Trench of any utility should not be in the zone of influence of the retaining wall or of the building. All construction utility permits for utility and street improvements will require separate plan submittals. All utility plans shall confirm to the Renton Drafting Standards. A licensed Civil Engineer shall prepare the civil plans. Please visit the Development Engineering Forms page for the most up-to-date plan submittal requirements: http://rentonwa.gov/business/default.aspx?id=42473 A landscaping plan shall be included with the civil plan submittal. Each plan shall be on separate sheets. Fees quoted in this document reflect the fees applicable in the year 2023 only and will be assessed based on the fee that is current at the time of the permit application or issuance, as applicable to the permit type. Please visit www.rentonwa.gov for the current development fee schedule.