Gardening for Water Quality?

Jeff Geyer, the Water Specialist with the Laramie County Conservation District is visiting our blog for another post in the series about the “Laramie County Library Water-wise and Pollinator Bio-retention System (Project).” Read his post to learn about how gardens can play a huge role in our water quality!

Our growing city has spent and continues to spend tens of millions of dollars to deal with stormwater runoff. We have built huge flood detention ponds and installed miles upon miles of stormwater pipe throughout town. We’ve seen two new structures, Pumphouse Park Wetland and Civic Commons, incorporate biological water quality treatment into their design. These facilities are just big gardens that don’t only look good, but are actually used to help treat pollution.

In a bigger realm, “Best Management Practices” (BMPs) such as wetlands, bioswales or green bumpouts are constructed by municipalities and agencies for remediation of polluted sites or to treat stormwater surges in and around municipalities. These plantings can physically remove all kinds of pollutants from soils and waters, so much so that some cities even use them to treat sewage. It’s almost like plants have been designed to clean up after the mess we humans make.

“Well”, you say, “I don’t have room to install a wetland in my backyard.” That’s okay! Massive wetland systems aren’t the only way we can do our part in dealing with stormwater runoff issues here in Cheyenne. I believe the easiest way for an individual in Cheyenne to help with stormwater management is to try and trap every drop of water or snow that falls on their property. How? Install a rain garden. A rain garden is a smaller dedicated space designed to capture and treat runoff from downspouts or other impermeable surfaces.

How do rain gardens work? First, by trapping the runoff from your property, you are decreasing the city requirements for stormwater management and therefore the need to keep throwing millions of dollars at infrastructure. Lessening the flows coming off your property lessens the flows running down the streets, which lessens the flows into the storm drains and ultimately lessens the flows into Crow Creek and Dry Creek. Storm flows in both drainages increases erosion and sedimentation to the point that Crow Creek is listed as “impaired” on the Wyoming Department of Environmental Quality 303(d) list. By simply reducing runoff from your property, you reduce the negative side effects associated with flooding. By the way, we live in an area that only sees 15 inches of precipitation per year, so don’t you want to save every bit you can and reduce your water bill as well? Rain gardens can be designed to handle our monsoon seasons as well as our dry seasons without fail.

Second, BMPs, including our rain gardens, use multiple means to clean up our environment. One means of plant treatment is phyto-extraction. This is where plants are used to concentrate metals in both leaves and roots. This type of remediation treats all types of metals including cadmium, lead, chromium and mercury. In Rhizo-filtration, plant roots actually absorb pollutants from contaminated liquid effluents and can degrade organic compounds. Phyto-stabilization reduces the passage of metals to either groundwater or the atmosphere. Phyto-stimulation is an interesting plant function where a plant will exude a fluid from its roots which promotes the growth of microorganisms such as bacteria or fungi that are capable of biodegrading pollutant compounds. In Phytovolatilization, a plant takes up either heavy metals or organic compounds, bind with them or modify them, and release them into the atmosphere as a harmless byproduct via transpiration. Finally, Phyto-decomposition occurs when either aquatic or terrestrial plants capture organic compounds and store them or allow them to decompose as a lesser or non-toxic byproduct. Plants are amazing if you use them correctly. In golf courses and parks with adjacent water bodies, we’ve even seen the incorporation of buffer strips to capture the nitrogen put on during fertilization. Let the plants work for you.

Lastly, a well-designed rain garden can provide blooming plants all summer season. There are a plethora of damp to wet-loving plants that are attractive. These rain garden plants tend to ebb and flow with the given moisture and outcompete weeds within the garden. No landscaping is maintenance-free, but I believe after three years, the right plants in the rain garden will outshine their foes and become a more attractive and nearly hassle-free garden that is easier to maintain than a turf monoculture.

Diversity is our ally in this fight, so if we don’t have to water a garden as much as a lawn or have to weed it as often, we can actually sit and enjoy it. The garden’s attraction isn’t just for your benefit, but can help serve multiple pollinators including bees, butterflies, and hummingbirds. Become a water-wise, phyto-remediating, pollinating gardener all while being a beneficiary and doing your part as a Cheyenne resident.

You can’t eat the elephant all at once. You have to eat it one forkful at a time. Even though your yard is probably 1/20,000 the size of Cheyenne, it’s a start. True desert states like New Mexico and Arizona have become experts in this science. The landscaping some of these folks have grown on so little rain is amazing, just by utilizing their runoff. This isn’t just a warm and fuzzy feeling either. We have scientific research showing that rain gardens actually improved water quality in Minneapolis, Minnesota.

The Laramie County Library flood detention water-wise conversion project is a HUGE example of a rain garden. We are utilizing the library’s rooftop and parking lot runoff to water the newly converted wet meadow planting, which was previously a turf grass monoculture. The library used nearly 3 acre-feet of water (three football fields, one -foot deep in water) to water their property. After this massive rain garden’s establishment in three years, we think the library’s water bill will be cut in half…or less! Not to mention, the plantings will help clean up the parking lot’s hydrocarbons and any other pollutants, before they make their way into the storm drain. It’s a win-win for the library.

So please, start searching rain garden websites for ideas. Start pouring through nursery catalogues for rain garden plants meant for this zone. Stop by Laramie County Library System for ideas or call your Laramie County Conservation District and speak with me, Jeff.

Jeff Geyer
*Water Specialist with the Laramie County Conservation District

* The District’s Water Specialist dwells in all realms of the hydrologic cycle from aquifer recharge to stream restoration to yes, even stormwater runoff. The Conservation District has recently been gaining ground in the water conservation world by performing a few water-wise conversions within Cheyenne. One such water-wise conversion is the massive “Laramie County Library Water-wise and Pollinator Bio-retention System (Project),” a.k.a. the library’s pollinator rain garden. The Conservation District secured a Wyoming Department of Agriculture’s Specialty Crop Block Grant to finance the purchase of the plants, tools, and anything else necessary to complete the project by September, 2021.