Self sustaining rain gardens and rain harvesting

In a half inch rain, 312 gallons of water can be captured from a 500 sq. ft. roof. In a one inch rain, 9'x19' rain gardens can capture 49,000 gallons of water from 150 homes. That is 49,000 gallons of water that will not go into the storm water system.
Building a rain garden is not difficult. Select a place where the rain water will pool from rain gutters or gullies. The shape of the garden should be somewhat like a bowl, with a deeper center and an area where runoff can escape during a heavy rain. Till the soil to 8 to 12 inches deep and amend it with organic matter such as leaves or compost. If the soil is hard clay you can even add coarse sand. Diatomaceous earth is also recommended to help break up the soil to make it more porous. The goal is to amend the soil enough so that water will percolate into the ground and not stand in the area for more than 24 hours. Use plants that are both drought tolerant and moisture tolerant, some with deep roots and some with shallow roots. Perennials, native plants and grasses will work fine. Lists of recommended plants can be found on the internet.
Rain harvesting is designed to store water for future watering of gardens, etc. Rain barrels can be set under drain spouts, but it works best when you have leaf guards on the gutters because the water needs to be debris free. A 1,000 gallon water storage system will provide one inch of water for 8 weeks. The systems that Eric sells are equipped with a pump which gives pressure for a hose. A rain barrel needs to be plumbed away from the house and designed with an overflow for heavy rains. A large underground storage tank can be put under grass or permeable pavers. As with a rain garden, do not let the water pool close to the foundation of the house or you may end up with water in the basement. A large storage system needs to have circulation (bubbler, aerator, etc.) to oxygenate the water. Eric said the cost is not cheap - a 1,500 gallon rain harvest system can cost between $7,000 and $10,000.
As the purity of our lakes and streams become a bigger and bigger issue, rain gardens and rain harvesting will become more and more important. Eric said that there are three federal government entities dealing with water purity: FEMA, EPA and the FDA. This makes it more difficult to comply with their many regulations.
Eric works for Complete Aquatics, a wholesale supplier for water gardens and lake management. They also deal with storm water retention and water purity.
Editor's note: Floyd and I have installed two 50 gallon rain barrels (cost about $50 per barrel) under a couple of our drain spouts and it takes only a ½ inch rain to fill each barrel. We are a part of a group in Holton, Holtonians 4 Stormwater Solutions, that is working to improve storm water run-off with rain barrels and rain gardens. We have received a state grant to help pay for the rain barrels and rain gardens as well as public education about them. We have also gotten a federal grant to build a large bio retention cell at the top basin of the storm water source to slow down and purify the water before it enters a creek below which drains into the Delaware River.