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HomeMy WebLinkAboutPRE25-000313_ENG CommentsDEPARTMENT OF COMMUNITY AND ECONOMIC DEVELOPMENT M E M O R A N D U M   DATE: October 16th, 2025     TO: Jill Ding, Senior Planner     FROM: Yong Qi, Civil Engineer III     SUBJECT: South Wastewater Treatment Plant (STP) Trailer Replacement 1200 Monster Rd SW PRE25-000313      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) 2423049006. The following comments are based on the pre-application submittal made to the City of Renton by the applicant. WATER Domestic water service to all of the buildings within the treatment plant are served by a privately-owned interior water supply line. Fire protection service to the plant is being provided by privately-owned interior water mains for fire service hydrants. The private water mains are connected to the City’s water system at 2 locations, the first connection is at the west end of the SW 7th Street Bridge and the second connection is near the access road along Monster Rd SW. There is an approved backflow prevention assembly (RPBA) at each of the two (2) connections to the City’s water system. The proposed trailers must be installed at least 10 feet away from the existing water mains. This clearance is necessary to ensure adequate access for maintenance and repairs, as well as for valve operations in the event of an emergency. SEWER A utility plan shall be provided to demonstrate that any proposed sewer connection for the project will comply with the requirements for proper sewage disposal. SURFACE WATER Drainage plans and a drainage report complying with the adopted 2022 Renton Surface Water Design Manual (RSWDM) will be required. Refer to Figure 1.1.2.A – Flow Chart in the 2022 RSWDM to determine what type of drainage review is required for this site. The site falls within the City’s Peak Rate Flow Control Standard (matching existing site conditions). The site falls within the Black River drainage basin. Drainage report and drainage plans based on 2022 RSWDM are required to be provided. Storm drainage improvements along all public street frontages are required to conform to the City’s Street and stormwater conveyance standards. Any new storm conveyance installed on or off-site shall be designed and sized in accordance with standards found in Chapter 4 of the 2022 RSWDM. New storm drains shall be designed to account for the total upstream tributary area, assuming developed conditions for onsite tributary areas and existing conditions for any offsite tributary areas. If the new plus replaced pollution generating impervious surface exceeds 5,000 SF, the applicant will be required to provide enhanced basic water quality treatment. All proposed stormwater facilities shall be designed in accordance with the current RSWDM 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 all proposed detention and/or water quality vaults. 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 appliable to the project. The final drainage plan and drainage report must be submitted with the utility construction permit construction. 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 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 current City of Renton Surface Water Standard Plans shall be used in all drainage submittals. The development is subject to a surface water system development charge (SDC) fee. Fees will be charged based on the rate at the time of construction permit issuance. The 2025 Surface water system development fee per dwelling is $0.94 per square foot of new impervious surface, but not less than $2,350. The developer will receive a credit for demolition of the existing structures. The full schedule can be found here. TRANSPORTATION Based on the submittal items and project description, there are not anticipated transportation requirements associated with this scope of work. GENERAL COMMENTS Fees quoted in this document reflect the fees applicable in the year 2025 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.