Rain Gardens

What are Rain Gardens?

A rain garden is a landscaped depression that captures rainwater runoff from roofs, driveways, streets, or parking lots. Runoff captured in a rain garden is temporarily ponded before infiltrating and percolating down through the natural soils. This allows for plants to use the water and for pollutants to be filtered out. Rain gardens can come in many shapes and forms to add an attractive feature to a landscape while also serving a real function helping to manage and treat stormwater runoff.Picture10

Why Install a Rain Garden?

Installing a rain garden helps restore a landscape’s ability to manage water more sustainably. Historically, the prairies and savannas of Iowa held and infiltrated most rainfall, and surface runoff was rare. Rainfall was absorbed and moved down through the soil to become groundwater flow. Cool, clean groundwater fed and maintained rivers, streams, wetlands, and lakes.

Today our impervious and compacted urban surfaces shed dirty runoff water with almost every rain. This dirty runoff goes down into storm drains and feeds receiving streams, which causes water quality problems and contributes to flooding. Rain gardens help reduce runoff and protect water quality.

Rain Gardens in the Easter Lake Watershed

At the start of the Project, Polk County Conservation wanted to lead by example by installing rain gardens throughout Easter Lake Park. Today in the park, near the covered bridge and shelter 1, rain gardens can be seen managing nearby parking lot runoff. The rain gardens help to naturally infiltrate parking lot runoff and provide a landscaping feature full of flowering plants and grasses native to Iowa, that are also great for pollinator species.

As part of the Easter Lake Watershed Project, residents, businesses, and other landowners  located within the watershed are eligible for up to 75% cost-share for rain gardens. Contact the watershed coordinator for more information.

Additional Resources

Visit Rainscaping Iowa’s website for more information on rain gardens and other rainscaping practices.

Rain Garden Design and Installation Manual