City of O’Fallon, MO; Phase 2:
August, 2014. System design and material supplied by Rainwater Harvesting Supply Company, LLC. Installation by Rainwater Harvesting Supply Company, LLC and Colonel Landscaping Services, Inc. This installation was requested by the stormwater management coordinator of the City of O’Fallon to demonstrate proper storm water mitigation through rain water harvesting. The water will be re-used for landscape irrigation and rain garden plant support.
Specifications: (1) 500 gallon and (1) 150 gallon rain water harvesting tanks; leaf separator; first flush diverter; winterization “knife” valve and raised landscape block platform. Water is captured from a nearly flat painted steel roof in an industrial environment. This environment strongly suggests the inclusion of the first flush diverter which disposes of the first several gallons of water from the roof. It is likely that this initial “flush” of water will be high in suspended contaminants (dust particles). A calculated volume if water is diverted from the downspout and directed to the drainage area. The larger vertical pipe fills with the first flush of water and diverts the cleaner water to the storage tanks. This vertical pipe then slowly discharges the dirty water from the large pipe into the drainage area via a small diameter hose. This empties the flush diverter pipe making it available for first flush when the next rain event occurs.
The knife valve simplifies winterization of the system. The leaf separator at the top of the downspout assembly prevents leaves, twigs and large debris (1/4” or more) from entering the system.
One storage tank is raised on a concrete platform to equalize the full level of the different size tanks. Each tank has a hose spigot for connecting garden hoses. The landscape block assembly is joined using masonry adhesive. The inside cavities of all the blocks are filled with 1” gravel. The storage tanks are anchored to the concrete pad for safety and wind resistance.