8920 EVERGREEN WAY THE RESERVE 2025-07-25

CITY OF EVERETT STORMWATER MANAGEMENT MANUAL 4.2.3 S.3 Cover the Activity with a Roof or Awning Not every activity can or needs to be located inside a building. In many cases, a simple roof or awning will protect the activity from coming into contact with stormwater, and usually at a lower cost than a • complete building. If a structure will be built,permits must be obtained from the City's Planning Department(425)257-8731,which will look at Fire Code requirements and Zoning Code Provisions. The roof structure can be designed in several ways. One option is a lean-to type of structure,where sheets of corrugated steel,fiberglass, aluminum, or similar impermeable material are attached to the wall of a building and are supported by sturdy poles. Similarly, if there is no building to attach to,roofing materials can be sufficiently supported at all four corners as a stand-alone cap, or a waterproof tent canopy can be used. The area of the roof cover should be sufficient to prevent any precipitation from reaching the covered materials. Another option for covering an activity is to use an overhanging awning of sufficient size to prevent rain from reaching the materials. Many of the building permit, fire code, and zoning requirements will also apply to these structures. Activities such as fueling operations may be more conveniently covered by an island-type overhanging roof. This type of roof is supported by columns along the center of the structure rather than at the corners, enabling vehicles easy access underneath while still providing sufficient protection from rain. Note that floating fuel stations(such as some used for refueling boats)cannot be covered, according to the Fire Code. The particular roof cover option used at a given site is subject to the site layout and available space, affordability, and limitations imposed by other regulations. Structural cover options other than those given above can be used if they perform the same function. This BMP should usually be implemented in conjunction with sump or sanitary sewer drains and provisions for prevention of stormwater run-on into the covered area. BMPs S.6 and S.7 in this chapter present information on sump installation and run-on prevention. 4.2.4 S.4 Cover the Activity with an Anchored Tarpaulin or Plastic Sheet Some activities,such as stockpiling of raw materials, can be effectively covered with a sturdy tarpaulin or heavy plastic sheet made of impermeable material. Weights such as bricks,tires, or sandbags should be used to anchor the cover in place. Care should be taken to ensure that the tarpaulin or sheet covers the activity completely and that stormwater run-on does not penetrate significantly under the cover. If several sheets are used to form a cover,the sheets should be tethered together or laid in an overlapping manner. If necessary,pins or stakes should be used to anchor the tarpaulin to the ground. The tarpaulin must be inspected daily to ensure that no holes or gaps are present in the tarpaulin coverage. The tarpaulin covering will be easier to keep in place and will last longer if some form of wind protection is possible. Attempts should be made to locate stockpiles adjacent to buildings where winds are reduced, but not in between buildings where a wind tunnel effect can occur. Tarpaulins are an inexpensive and cost effective BMP for many activities. This BMP can be combined with runoff containment/run-on prevention curbs, dikes, and berms for better effectiveness(see BMP S.7 for more information). 4.2.5 S.5 Pave the Activity Area and Slope to a Sump or Holding Tank This BMP applies to several activities that cannot be covered effectively. It is particularly suited to activities with the potential for leaks and spills,but that otherwise do not generate excessive amounts of Volume IV— Source Control 4-3