Rain Gardens

When people develop land, they change the amount of rain water that runs off. Roofs and streets don't allow the rain water to soak into the soil. Most developments cause an increase in runoff and a decrease in infiltration. This has two effects.

1 The extra runoff can cause the streams and rivers to overflow. This flooding can cause homes and businesses to be damaged. Sometimes people die when they are swept away by the flood waters.

2 Since less water soaks into the soil the water table can lower. This causes springs and wells to dry up. Fish in the streams that depend on a constant supply of fresh water can suffer or die. People who depend on well water can face shortages and rationing.

Some communities are requiring people to accept the responsibility for the extra runoff their development causes. Developers are required to devise a plan to hold back the extra runoff. Their plan needs to allow the extra water to soak into the ground over a few days.

One strategy is to build rain gardens. A rain garden is a dual purpose area. Most of the time, the rain garden is a nature trail, soccer field, flower garden etc. When a heavy rain causes extra runoff, the excess water is stored in the rain garden. After a few days the water has soaked in and the area is available for recreational purposes again.

The rain garden needs to have plants to help the water soak in. The plants also help reduce erosion. The water needs to soak in over 2 or 3 days so the plants don't drown. It is also important that the water doesn't get over 2 feet deep. If the water gets deep its weight will compress the soil. Packed soil won't absorb the water as quickly.

The type of soil determines the maximum depth of the rain garden.

2. background
1. introduction

4. model1