Why should rain be collected?

One inch of rain falling on a 10-square-foot roof can produce about 6 gallons of stormwater runoff. Roof downspouts typically direct the roof runoff directly onto hard surfaces such as driveways, streets, and sidewalks that prevent the water from soaking into the ground. 

During heavy rains only a small portion of the precipitation absorbs into ground through lawns and unimproved areas because of the high clay content in local soils. The additional stormwater from hard surfaces like streets, parking lots, driveways, roofs and patios (impervious areas) can often cause serious problems for our downhill neighbors.

The impervious area associated with a medium size house can produce over 2700 gallons of stormwater runoff  during a one inch per hour rainfall! This impervious stormwater can also collect pollution along the way and damage the ecosystem in Black Creek, Pebble Creek and the River Des Peres.

What is a Rainscape?

Rainscape RainScapes are watershed friendly ways to slow, absorb, clean and reduce rainfall runoff. RainScape projects are designed to slow the runo and reduce the amount of runoff  and pollutants entering our streams. Stormwater that soaks into the ground is ltered by the soil and replenishes groundwater. Additional environmental bene ts of these projects include reduced energy and water consumption, increased wildlife habitat and improved air quality in our suburban landscape. Rain gardens, rain barrels, bioswales, dry wells and permeable pavements are common Rainscape projects.

Harvesting Rain Water

Rain barrels and cisterns collect and store a portion of the rainwater from your roof. The most common type of rainwater collection system used by homeowners is a rain barrel. Rain barrels come in a variety of sizes but typically as a 55-gallon container that collects roof runoff.

Rain barrels can be added to any building with gutters and downspouts, and they have an outlet that can be connected to a garden hose so the rainwater can be used to water landscaping plants, lawns, and gardens. All rain barrels require an overflow port. Cisterns are sealed tanks that can be located above ground, partially buried, or below ground.

Cisterns are larger than rain barrels and they can collect water from several downspouts from one building’s roof or from multiple roofs if they are large enough. Large cisterns may require a permit, so please check with the City before beginning the project. When cisterns or rain barrels are full, the over ow should be directed to a safe location away from the building foundation. Overflow may also connect into a dry well, rain garden, or other area where the runoff can infiltrate into the ground on your property.

By collecting your roof runoff in rain barrels or cisterns, you can reduce stormwater runoff from your property. Stormwater runoff is reduced, because you are collecting the stormwater and allowing it to soak into the ground when you use it for irrigation. When you use the rainwater to water your gardens and landscaping, you also use less potable (tap) water for this purpose, which can lower your water bills. Since rain barrels and cisterns collect rainwater for use on site, they can reduce the harmful effects to streams caused by large and rapid stormwater runoff flows.

More Information

While these projects might sound small in the grand scope of stormwater, each one cumulatively can make a difference. The Public Works Department is working with the Deer Creek Watershed Alliance and Missouri Botanical Gardens to and grant opportunities and RainScape education re- sources for residents. For more information contact the Public Works Dept. at 314.993.0252 or email Bruce McGregor, Director of Public Works.