HomeMy WebLinkAboutRS_DRAINAGE_TECHNICAL_INFORMATION_REPORTStormwater Technical Information Report (TIR) Memo
Project Information
Project: Oasis Home Daycare
Address: 4508 NE 4th St, Renton, WA 98059
Parcel #: 102305-9117
Applicant: Hector Vigna
Phone: 206-779-2967
Email: hovdesing@outlook.com
Date: April 09, 2025
Project Description
The proposed project is a tenant improvement to convert an existing building from office use to a daycare facility. The
scope includes interior renovations, the addition of an ADA-accessible ramp, installation of a 3' high retaining wall,
perimeter fencing, and a new 300 SF permeable playground.
There is no net increase in impervious surface area. Minor land disturbance may occur for the ramp, retaining wall, and
playground area; however, the total disturbance area is estimated to be under 7,000 SF. No new vehicular hard surfaces
or roof area are proposed.
Stormwater Applicability - 2022 RSWDM
Per Section 1.1.2.B of the 2022 Renton Surface Water Design Manual (RSWDM), this project qualifies for the Small
Project Exemption, as it meets all the following:
- <2,000 SF of new plus replaced impervious surface
- <7,000 SF of total land disturbance
- Discharges to an existing, stable stormwater system
- Does not trigger Minimum Requirements due to critical area discharge impacts under typical thresholds
As such, the project is exempt from Minimum Requirements #1-#9. No flow control or water quality treatment facilities
are proposed or required.
Sensitive Areas
The site contains a Category III wetland and a non-fish bearing (Ns) stream, both mapped per the Renton Surface Water
Atlas. A 100-foot wetland buffer and 15-foot building setback area are shown on the site plan. Portions of the proposed
ramp, fence, and retaining wall may fall within the buffer area.
Due to this proximity, a Critical Areas Determination (CAD) is recommended or may be required to confirm buffer
encroachments and ensure compliance with RMC 4-3-050.
Conclusion
This project is consistent with the Small Project Exemption in the 2022 RSWDM. There is no increase in impervious
surface, and the minor scope of land disturbance supports the exemption from full stormwater requirements.
Coordination with the City of Renton Planning Division is ongoing to address any potential wetland buffer encroachment.