Pullman’s Design Standards
Section E – Erosion Control
Section F – Storm & Surface Water Drainage
Pullman’s Standard Construction Specifications
In addition to the above documents, Pullman has adopted the Standard Specifications for Road, Bridge, and Municipal Construction produced by WA State Dept. of Transportation. The most current version can be viewed at WSDOT’s website below.
Additional Pullman Stormwater Design Considerations/Requirements:
(Last Revised 02/08/08)
·When determining the need for stormwater detention/retention, there are two thresholds to consider:
1) Is impervious surface being increased by a net of >10,000 sq. ft.?
2) Are >10 parking stalls being added?
If either answer is “yes” then stormwater detention/retention is required.
·The current minimum standard for managing stormwater is designing to a 10 yr 24 hour storm event. Except for Hatley Basin, which has its own set of criteria (contact Public Works – Engineering staff for specifics).
·Regardless of where the stormwater basins are located, the outlet structure should be designed to be staged to provide attenuation during lesser storms (i.e. 2 yr & 5 yr).
·Contractors/engineers needing topographic maps with contours can access them on the City’s website (Departments / Public Works / City Maps / Aerial Maps).
·All new construction over an acre in size (or parcels that are smaller but are a part of a larger development) falls under the WA Dept. of Ecology’s Construction Stormwater General Permit and must have a SWPPP developed and regular CESCL inspections. A guide to meeting the requirements of the General Permit can be found at www.ecy.wa.gov/pubs/9937.pdf