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Rain Gardens

What is a Rain Garden?

A rain garden captures rain from frequent events that generate 1.25” rainfall that generates runoff from roofs, driveways or yards. It 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  a 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 run into streets and storm drains. Dirty runoff that enters storm drains is sent directly to “receiving waters” – our rivers, streams, lakes, ponds or wetlands.

Iowa Rain Garden Design & Installation Guide – Third Edition

The third edition of the Iowa Rain Garden Design & Installation guide features updated design calculations, material specifications, plant lists, and maintenance checklists. Readers begin by learning the importance of rain gardens and where to located them in a yard. Two designs are offered, basic and enhanced rain gardens, the latter featuring subdrain infrastructure. Detailed instructions are provided for calculating the correct size and depth for managing most rainfall events in Iowa. Once the design is complete, instructions are included for creating a comprehensive list of materials and installing a rain garden as a DIY project or as a contractor-led project. The final chapters provide guidance on plant selection and rain garden maintenance. Several helpful appendices are included, such as sample rain garden plant layouts and how to calculate soil amendments.

The guide was developed by the Iowa Stormwater Education Partnership (ISWEP) in cooperation with the Iowa Department of Agriculture and Land Stewardship (IDALS) Urban Conservation Program, the Iowa Department of Natural Resources (IDNR), and Polk County Soil and Water Conservation District. Development of the guide was led by an Advisory Committee comprised of municipal stormwater professionals, state officials, and design consultants.

Recommended Paperwork for Cost-Share Funding

We have compiled a convenient packet of paperwork that is typically submitted when applying for cost-share funding for basic and enhanced rain gardens in Iowa. All forms are fillable and can be saved digitally.

Rain Garden Gallery