Does my construction project need to mitigate stormwater runoff?
- Per the 2019 DOE manual, any project resulting in 2,000 square feet, or more, of new plus replaced hard surface areas OR does land disturbing activity totaling 7,000 square feet or greater must meet the Minimum Requirements of the DOE manual.
Note: Replaced Hard Surface is defined as the removal and replacement of hard surfaces down to the foundation for structures, and for other hard surfaces, the removal down to bare soil or base course and replacement.
Stormwater Threshold 1
- Projects proposing greater than 2,000 square feet of new plus replaced hard surfaces OR land disturbing activity totaling 7,000 square feet or greater, but less than 5,000 square feet of new plus replaced hard surfaces triggers minimum requirements 1-5.
Stormwater Threshold 2
- Projects proposing greater than 5,000 square feet of new plus replaced hard surfaces OR converting ¾ acres, or more, of vegetation to lawn or landscaped areas, or converting 2.5 acres, or more, of native vegetation to pasture must meet minimum requirements 1-9.
Projects meeting thresholds 1 or 2 above must complete a civil application through the CityView Portal and provide the following items at the time of application submittal:
- Surveyed Site Plan designed by a Washington State Professional Engineer. Additional information regarding this requirement can be found within Volume III-3.2 of the DOE manual: Preparing a Stormwater Site Plan. Also see city Design Standards and Standard Details.
- Geotech Report determining the site-specific design infiltration rate and seasonal high groundwater elevation. Note: projects triggering minimum requirements 1-9 must continuously monitor groundwater during the wet season defined as December 1st – April 1st. You can find more information regarding design infiltration rates here.
- Construction Stormwater Pollution Prevention Plan (SWPPP) outlining how the project will meet the 13 elements to control erosion and prevent sediment and other pollutants from leaving the site during construction of the project. Note: this is minimum requirement #2, but the City of Puyallup requires this document to be submitted separately.
- Stormwater Drainage Report. This report shall include the minimum requirements as required by the DOE manual, a basin map outlining the square footage of mitigated stormwater areas, a downstream storm capacity analysis, an on-site storm pipe capacity analysis, calculations as applicable for Runoff Treatment (MR6), Flow Control (MR 7), Wetland Protection (MR 8), and any other required analysis.