What is Rainscaping?
Rainscaping is the practice of designing landscapes to capture, absorb, and use rainwater where it falls. Rather than sending water off-site through storm drains, the water slows down, spreads across the landscape, and soaks into the soil.
In Indiana, spring often brings intense rain events that can quickly overwhelm drainage systems, soils, and rivers. Rainscaping offers a different approach. Instead of treating rainwater as something to get rid of, it becomes a valuable resource that benefits both the landscape and the environment.
Why Rainscaping Matters
Across the Midwest, rainfall is becoming less predictable, with more intense storms delivering large amounts of water in a short period of time. Many landscapes are not designed to absorb this volume quickly. Compacted soils, large areas of turf, and paved surfaces all contribute to rapid runoff of soil, nutrients, and pollutants into nearby waterways.
With rainscaping, the goal is to keep water on-site and allow it to infiltrate slowly (Fig. 1). As the water moves through the soil, it not only irrigates the landscape, but it’s filtered, which reduces runoff, improves water quality, and eases the burden on stormwater systems.
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- Figure 1. A rain garden in downtown Lafayette captures runoff from nearby roads and sidewalks, slowing and filtering water before it enters the stormwater system. Credit: Amy Thompson, Purdue University.
How Rainscaping Works
The principle of rainscaping is simple: slow water down and give it time to soak in. This can be achieved in a variety of ways depending on the site conditions. The right approach depends on how water moves through your landscape.
The most common method for slowing runoff is with a rain garden, which is a shallow depression planted with species that can tolerate both wet and dry conditions (Fig. 2). The rain garden holds water after a storm and allows it to infiltrate within a day or two. Species that tolerate “wet feet” are planted in the bottom of the basin while drought tolerant species are planted at the top of the slope.
Other landscapes may be better suited for bioswales, particularly sloped areas where water naturally flows across the site (Fig. 3). Bioswales are shallow channels that slow and direct water, allowing it to infiltrate as it moves. As runoff passes through the soil and plant roots, sediment and pollutants are filtered out.
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- Figure 2. Water infiltrates into a rain garden in Bloomington following an intense rain event, demonstrating how these systems manage excess runoff from the nearby parking lot. Credit: Amy Thompson, Purdue University.
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- Figure 3. A bioswale outside Purdue’s Horticulture building captures and directs runoff from downspouts before entering the stormwater system. Credit: John Orick, Purdue University.
Getting Started with Rainscaping
Rainscaping does not require a complete redesign of the landscape, and the first step is simple observation. Spring is an ideal time to evaluate your site, especially during intense rain events. Observe how rainwater moves off hard surfaces, out of downspouts, across the landscape, and into storm drains. These observations will often point directly to areas for improvement and potential locations for rainscaping.
Avoid placing rain gardens in areas that remain saturated for several days after a storm, as this indicates a slow infiltration rate. Instead, focus on capturing water “upstream,” where it can soak in before reaching problem areas.
Once potential locations are identified, further site evaluation is needed. Estimate the amount of runoff entering the area and perform a simple infiltration test to determine the appropriate size and depth needed to handle larger rain events.
Plant species that tolerate both wet and dry conditions are essential, as these areas regularly cycle between extremes. Many plants native to Indiana are well adapted to these conditions, including purple coneflower, Joe-Pye weed, and prairie dropseed. By selecting species with varying heights, textures, and bloom times, these gardens can be both functional and visually appealing (Fig. 4).
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- Figure 4. Rain gardens can be designed to manage water effectively while adding visual interest to the landscape. Credit: Karen Mitchell, Purdue University.
Rainscaping is a practical approach to managing water in the landscape. By slowing runoff and encouraging infiltration, it reduces common problems while supporting healthier landscapes and more resilient ecosystems.
To learn more, the Purdue Rainscaping Education Program provides training and resources on planning, installation, and maintenance of rain gardens.
