3214 BROADWAY BROADWAY KINECT APARTMENTS 2021-08-11

CITY OF EVERETT STORMWATER MANAGEMENT MANUAL ID 5. Used to divert small seasonal streams away from construction. They have been used successfully on culvert replacement and extension jobs. Large flex pipe can be used on larger streams during culvert removal, repair, or replacement. 6. Connected to existing down spouts and roof drains and used to divert water away from work • areas during building renovation, demolition,and construction projects. There are now several commercially available collectors that are attached to the pipe inlet and help prevent erosion at the inlet. • Design and Installation Specifications • Size the pipe to convey the flow. The capacity for temporary drains shall be sufficient to handle a peak flow equal to 1.6 times the 10-year, 1-hour time step flow indicated by an approved continuous runoff • model. If a 15-minute(or less)time step is used,no correction factor is required. 411 1. Use care in clearing vegetated slopes for installation. • 2. Reestablish cover immediately on areas disturbed by installation. 3. Use temporary drains on new cut or fill slopes. • 4. Use diversion dikes or swales to collect water at the top of the slope. 5. Ensure that the entrance area is stable and large enough to direct flow into the pipe. 6. Dike material shall be compacted to 90 percent modified proctor to prevent piping of water through the berm. The entrance area is a common failure location. • 7. The entrance shall consist of a standard flared end section for culverts 12 inches and larger with a • minimum 6-inch metal toe plate to prevent runoff from undercutting the pipe inlet. The slope of • the entrance shall be at least 3 percent. Sand bags may also be used at pipe entrances as a temporary measure. 8. The soil around and under the pipe and entrance section shall be thoroughly compacted to prevent • undercutting. 9. The flared inlet section shall be securely connected to the slope drain and have watertight • connecting bands. • 10. Slope drain sections shall be securely fastened together, fused or have gasketed watertight fittings,and shall be securely anchored into the soil. • 11. Thrust blocks should be installed anytime 90 degree bends are utilized. Depending on size of pipe and flow,these can be constructed with sand bags, straw bales staked in place,T-posts and • wire,or ecology blocks. ID 12. Pipe needs to be secured along its full length to prevent movement. This can be done with steel • T-posts and wire. A post is installed on each side of the pipe and the pipe is wired to them. This • should be done every 10 to 20 feet of pipe length or so,depending on the size of the pipe and quantity of water to be diverted. 13. Interceptor dikes shall be used to direct runoff into a slope drain. The height of the dike shall be • at least 1 foot higher at all points than the top of the inlet pipe. 14. The area below the outlet must be stabilized with a riprap apron(see BMP C209 Outlet • Protection, for the appropriate outlet material). • 15. If the pipe slope drain is conveying sediment-laden water,direct all flows into the sediment • trapping facility. • Volume II—Construction Stormwater Pollution Prevention 3-42