Storm Water Detention Plan
Click to enlarge
Storm Water Detention
Underground Water Storage Tanks
STORM WATER DETENTION and management is becoming a routine component in land development projects, particularly along riparian corridors where rain run off surge and silt are degrading water quality and disturbing the natural ecology.
Grading and paving disrupts the historical stormwater flow path and the natural soil absorption process. The resulting soil erosion and transportation of oils and trash into the drainage patterns must be remediated. The surface water speed and volume is reduced by temporarily "detaining" the rain surge water in ponds or tank systems and then releasing it more slowly over a period of hours or days to meet acceptable natural or historic run off rates.
Run off ponds temporarily hold the water but do little to remove floating trash and oil. In addition to being high maintenance, ponds are often an attractive nuisance as well as a breeding area for mosquitoes, if not properly managed.
Shallow ponds generally take up more space or valuable real estate than an underground storage tank system. Darco manufactures underground fiberglass cisterns that can be used for storm water detention and management. Underground tank systems can be designed to intercept sand, floating trash, and oils as well as store and release the clarified water at acceptable rates. Small upstream concrete interceptors are very helpful in removing floating trash and sand before they make their way to the underground storage tank.
Periodic maintenance is required on such systems. Sand, oil, and floating trash accumulation must be monitored and removed as necessary by vacuum truck. Fine suspended solids will pass through an upstream baffled interceptor but generally drop out while water is held in the large quiescent storage tank system. Silt accumulating in the bottom of the tank must be occasionally removed as well.