Protect our waterways: Plant a rain garden!

Protect our waterways: Plant a rain garden!

Article written by Lily Simko, LPOW Volunteer

Entering the smoky skies of fire season, rain is a wishful sentiment that will remain evasive in the weeks and months to come. So, while we soak in the hot days and watch the grass in our yards fade to yellows and browns, I offer a project that will keep you hopeful with thoughts of rain: the rain garden.

What is it? A rain garden is a garden built into a shallow dip in the ground, positioned directly in the path of runoff and is, perhaps, best known as a landscaping feature that can help prevent erosion and capture pollutants before they enter waterways. These special gardens often mimic features in nature that are scarce due to development. The rising popularity of the rain garden’s utility in a modern context is traced to a developer by the name of Dick Brinker during the early 1990s. In an effort to avoid installing a costly drainage system for a development, Brinker created an extensive rain garden on each property. He was able to complete the project spending about 75% less than he would have on drainage systems, upping property values with landscaping aesthetics, and preventing issues of polluted waterways and expensive upkeep that come with maintaining drainage systems (Dobson). While his project was monitored for several years and proved to be efficient, 30 years later the idea is still catching on. 

Here on the shores of Lake Pend Oreille rain gardens are an ever-applicable tool that can be used to keep our lake and surrounding bodies of water healthy, while adding character to our own yards. The typical lawn, with it’s turf grass, is wonderful on bare feet, but it’s shallow roots do not absorb water well and do little to prevent erosion and filter pollutants. Lawns also often include the use of fertilizer and weed killer, which then runs off into the nearby lake – polluting our shared waterways and potentially harming aquatic life. A rain garden offers the best of both worlds in keeping our feet and our lake happy. For our waterfront residents, a rain garden is best positioned at the base of the yard between the lawn and the lake. Here the garden will provide a buffer, capture loose sediments, prevent shoreline erosion with deep rooted vegetation, and absorb stray chemicals and pollutants.  If you live in a neighborhood, a strategic rain garden placed at the edge of your yard can capture street runoff carrying trash, oil, and sediment before it enters storm drains

A waterfront rain garden serves as a buffer zone

Minimizing sediment and other pollutants from entering waterways are the most obvious advantages of rain gardens, but there are even more subtle gains in store. By capturing water and allowing it to percolate into the soil, nutrients that would otherwise be washed away are retained, improving soil quality, and likely the productivity of your yard.

A roadside rain garden can help minimize flooding and capture pollutants

Additionally, when water is absorbed and filtered into the soil, groundwater sources are recharged. Resupplying groundwater is especially important in areas where residents depend on aquifers as their primary water source. As your garden develops, the variety of plants provide habitat for pollinators and other fauna. A final benefit of the rain garden is preventing flooding and minimizing the potential of water damage to property and home by purposefully directing water into a specific location.

While you may be convinced that a rain garden sounds like a great idea on paper, what does it really take to create your own rain garden and is the work worth the reward? If you’re already serious about cultivating a rain garden there are a multitude of sites with step-by-step instructions. These links provide several good resources: 

However, if you’re curious and looking for a quick overview of what it takes to build one, here is a quick step by step review of what it takes to cultivate a rain garden: 

A rain garden protecting shoreline and waterways

Step 1: Identify the goal of your rain garden.

Are you preventing runoff from your yard from flowing directly into the lake? Are you capturing water that would otherwise flow into a storm drain? Are you looking to redirect gutter runoff and prevent flooding in your yard? 

Step 2: Position your garden in the path of flowing water. 

Rain garden should be positioned at least 10 feet from your house. It is also important to avoid building them directly over septic systems. 

Step 3: Soil and percolation. 

No two soils drain the same, so before you get too far in, do a percolation test. Dig a 6 inch by 6 inch hole and fill with water. Check periodically to see if the water is draining. If the water is gone within 12-24 hours the spot you’ve chosen is rain garden worthy. Alternatively, if your soil does not drain well re-evaluate, embrace it, and perhaps look into cultivating a mini wetland. 

Step 4:  Dig in! 

Rain gardens typically range from 6-12 inches deep. PennState Extension offers some design advice with a three tier approach. Create a low zone, where the most water will collect. A middle zone with moderate water collection and the upper zone where the rain garden transitions into your yard and existing landscape. Or create an indentation by intuition, one that fits your landscape, style, and experience. 

Step 5: Make it a garden…add plants! 

 Native plants are best for rain gardens and require the least maintenance. Here is an extensive list of Idaho Native plants. A few commonly used in rain gardens include aspen, wild roses, serviceberry, lupine, ferns, and grasses. If you’re in Bonner County, check out Kinnikinnick Native Plant Society’s website for a list of native plants and gardening ideas!

Arrange water loving plants in the lowest points of your rain garden

Step 6: Keep it up! 

The first year your plants will require a little extra love. Weed and water regularly to give them a strong start.  

Step 7: In for the long haul.

After your plants are well established your garden will still need some maintenance, this will vary depending on the location and function of your garden.  Rain gardens that catch debris from streets will require you to remove litter, while others capturing high volumes of sediment will need to be periodically re-dug. You may be thinking “Yuck trash and sediment in my garden, no thank you!” But these are the visible results and rewards of this tool. If you see these signs you can be sure your garden is doing its job. 

So now is the time to take advantage of a brown grass yard. Start digging! The dirt will blend right in. While it might be a hot and dusty project now, when rain finally arrives you will be waiting and ready to celebrate with your very own rain garden.

Sources

Dobson, Sarah. Rise of the Rain Gardens, 5 Apr. 2016, thelivingcoast.org.uk/news/rise-of-the-rain-gardens. 

“Green Infrastructure: Rain Gardens.” Thewatershed.org, 7 July 2019, thewatershed.org/green-infrastructure-rain-gardens/. 

“Stormwater Best Management Practices Interpretive Trail.” Berks County Conservation District, pacd.org/wp-content/uploads/2009/08/SWBMP-Trail-Brochure-Rain-Gardens.pdf.