Agenda - Council - 04/24/1984 - Laserfiche WebLink

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I I I I I I I I i If low velocities cannot be achieved, then structures for water and grade control should be used to conduct the flows to a safe outlet. 4. PROTECT DISTURBED AND STEEP AREAS FROM STORM WATER RUNOFF Measures can be utilized to prevent water from entering and running over the disturbed or steep areas. Vegetating the disturbed areas and steep slopes may produce adequate Prot~ecti.on if no other measures are used. Other protectiye measures are diversion to cut off runoff and conduct it to a safe outlet, grass waterways or open channels to carry the flows over steep areas, or road systems curbed or ditched to carry runoff or divert it. Outlets should be established and stabilized before diverting runoff ~into them. 5. CONTROL, REDUCE AND DELAY STORM WATER RUNOFF ltunoff can be reduced by allowing it more time and more places to infiltrate into'the soil. This can be done by providing more "green" I ! I I I I areas and holding.'the water on these areas. Large flows can be reduced by delaying the runoff and allowing it to run off slowly when the storm ends. Roof top storage and detention ponds are two additional methods. 6. RETAIN SEDIMENT WITHIN THE CORRIDOR OR SITE AREA Sediment can be retained by two methods: filtering runoff as it flows by establishing strips of vegetation across the disturbed area and along channels, or by providing debris basins in which the sediment laden runoff is stored for a time to allow the sediments to drop out of the I I water before it leaves the construction site. The best way to control sediment, however, is to prevent erosion from occurring in the first place.