WHAT IS A RAIN GARDEN?
A rain garden is a flower garden that captures runoff from rain that falls on roofs, driveways or yards. A rain garden is a depression or a shallow bowl made in the landscape that is level from side to side and end to end. Runoff that travels to your rain garden is temporarily ponded - but it doesn’t stay ponded for long. Capturing runoff in a rain garden allows water to infiltrate into the soil rather than running into streets and storm drains. Dirty runoff that enters storm drains is sent directly into “receiving waters” - our rivers, streams, lakes, ponds, or wetlands.
WHY INSTALL A RAIN GARDEN?
Homeowners would be surprised to learn that hundreds of thousands of gallons of rain falls on an urban lot in a year. In Iowa, rainfall averages anywhere from 28-36 inches per year. That means an acre of land in Iowa will receive anywhere from 760,000 to 977,500 gallons of rain in a typical year. The owner of a half acre urban lot in central Iowa would receive approximately 434,500 gallons of rain each year (a little less in western Iowa; a little more in eastern Iowa).
It is hard to visualize how much water 434,500 gallons actually is. Imagine capturing all that rainfall in 50 gallon barrels. You’d need a row of barrels more than 4 miles long to hold all the rain a typical lot receives.