Rain Garden

Introduction

These areas are designed for intermittent or continuous rain. They may be dry most of the year, only filling with rain water and run off a few times a year. They are not permanent enough for most species to use for breeding or feeding, but they do prevent run off pollution, and enhance groundwater recharge. They can also help reduce flooding, erosion, and reduce waterway nutrification which causes ocean dead zones.

It is a good idea to pick native plants who will tolerate drought or flood conditions. Generally it is best to put plants who don't mind "wet feet" at the lowest part of the rain garden, with the more drought-tolerant plants around the rim. There should be no liners of any kind since rain gardens are intended to let rainwater permeate into the soil, but there should be an overflow. Never put these within 10ft of a building's foundation, and make sure that the overflow will not negatively impact any buildings, your neighbors, or others down hill.

Rain Gardens 101

17:00 minute video explains why rain gardens are important solutions for pollution and flood control, while filling other ecological services such as providing pollinator habitat.

This video offers helpful visuals and many tips for how to create a rain garden, vs what to avoid.

Types of Rain Gardens

Rain Gardens 101, Part Two: Types of Rain Gardens

2:13 minute video talks about different types of rain gardens based on where they are placed to prevent run off from different sources.

Bioswales

Swales are ditches designed to help retain water, and move it to a useful location while also allowing for absorption. 

Often swales just have grass, but they can also be planted intricately with many plant species including certain tree species. Doing so can boost biodiversity, and the plants can boost absorption capacity in terms of water as well as pollutants.

Curb-Cut Rain Gardens

These use inlets to allow roadside water to flow into the garden. This might involve drilling a hole or cutting away some of the curb all together. 

This isn't legal in all places, so check with your local laws first, and get politicians to change the rules if this method would help your community reduce flooding were it allowed.

Ditch-Side

These are placed right before ditches to help catch sediment from a property or roadway and before it impacts local waterways.

Down-Spout-Fed

These are fed by downspouts, and should be placed at least 10ft away from your foundation to prevent damage to the building.

Drainpipe Rain Garden

If your garden is too small for a regular rain garden (or perhaps you have an alleyway or street facing downspout with no space to dig) then creating a mini container garden to host wetland plants is the solution you need! 

These compact gardens can absorb and clean water before allowing it to run off. They can boost biodiversity, and add a natural looking point of interest to an otherwise ugly or boring part of your building.

These can be build right up against your wall, without risking the structure of your foundation, and only need occasional maintenance to remove and replace dead plants, or trim back any that have become overgrown.

4:45 minute video "Do you wish you had a pond, but don’t have the space? At WWT we have large wetland reserves, but it’s not only the large wetlands that have value for wildlife.

Here’s a great idea to turn your drainpipe into a mini pond and floodplain with built in water supply – you’ll have your very own wetland reserve that will attract wildlife, save water and look fantastic. And unlike a large wildlife pond, it’s virtually maintenance free. In this video we’ll walk you through step by step how to create your own mini wetland.

Full instructions and more hints and tips from our experts can be found on WWT’s website"

Path-Side Rain Gardens

These are dug to be slightly lower than the level of a path, patio, or roadway, allowing water to easily flow in, and making the pathway more useable even during rainfall.

Xeriscapes

Xeriscapes are known as drought resistant gardens for hot and dry climates, but they can be implemented anywhere rain is scarce.  People forget that even these places can sometimes get overabundant rain, and that there are still going to be some native plants what appreciate that extra rain.

If you live in one of these fickle climates, then consider incorporating a rain garden into or near your xeriscape. Xeriscape plants enjoy higher, drier soil, while your raingarden plants can often stand some swings between dry and wet roots. If your land is on the flatter side, consider using your excavated dirt to build some higher, and drier flower beds for your dry-soil-loving plants.

Benefits of Raingardens

Biodiversity

Carbon Capture

Runoff Capture

Temperature Control

Where to Place Rain Gardens

Farms

Farms can produce massive amounts of run off (after all they use more land than any other human activity), so planting riparian borders along waterways and planting rain gardens in strategic places can help reduce their impact naturally.

Communities

Schools

Children benefit greatly from having plants and wildlife around. They can be great educational tools, while making a schoolyard's temperature more comfortable year-round.

Rain gardens can be placed strategically to reduce flooding, keeping more of the outside area available for play time. The plants also help reduce pollution, which negatively affects IO and test scores as well as other developmental markers.

Gardens & Parks

Rain gardens can do a lot of work in a fairly small space. If your garden or local park often gets flooded by heavy rains, then digging and planting a rain garden may help solve a few problems at once. It may help prevent flooding all together, while allowing you to grow more water-thirsty plants than you'd otherwise be able to support as more of us face water-use restrictions.

Guides

Be aware that the plant species suggestions may not be appropriate for your area. Always verify that you are planting natives, and try to avoid invasive species.

Raingarden Size

Measure the surface area of the roof or driveway that will be feeding the raingarden. Divide this area by 4. This is roughly the appropriate area for the raingarden.

4:41 minute video "This video created in partnership with Winona County will walk you through the actions needed to properly maintain a rain garden from installation through year three and beyond!

This video explains the steps needed right after planting, then periodically for years after.

North America

Canada

USA

Considerations

Resources

Use the Natives button to find native plant species for your location.

North America

USA

Texas

Tools & Apps

Europe

UK

North America

USA

Minnesota

South Carolina

Organizations

North America

Canada

USA

Arkansas

California

Carolina

Colorado

Illinois

Minnesota

Mississippi

Ohio

Oklahoma

Pennsylvania

Texas

Washington

Wisconsin

Maps

International

Europe

UK

North America

USA

Grants & Funding

Europe

UK

National award schemes There are a number of key organisations offering grants and advice to community based projects e.g. 

North America

USA

California

A sustainable landscape will not only help you save on your water bill by reducing your water use. You will also help recharge the groundwater, reduce urban runoff and enhance wildlife habitat—overall benefiting yourself and the Los Angeles watershed."

Minnesota

Oceana

Australia

Western Australia

Further Reading