Last week, I was able to attend the two-day Stormwater Practices Inspections and Maintenance Workshop geared toward teaching the best ways to inspect and maintain stormwater green infrastructure.
No doubt, the workshop is tailored to a niche community that I happily take interest in, but understand that many others do not. This meant getting deep into the weeds about various runoff management devices and techniques that help us alleviate the problems with uncontrolled runoff while also examining the nuances between different installations.
Throughout this workshop, though, three simple points were reiterated as the foundational consideration whenever we implement a practice: rate, quantity, quality.
So, what do rate, quantity and quality mean? Well, storm runoff has three influencing factors that we need to address. The rate at which it flows, the quantity of water and water quality.
If you're hung up on the difference between rate and quantity, imagine the difference in trying to empty a bathtub of water through a straw and fire hose. You'll move the same amount of water far slower through the straw than the fire hose.
We want that, and in fact, our goal in tackling rate, quantity and quality is to create spaces that collect, reduce and improve the incoming water.
Following this sequence, collection is the first stage of our process. We collect it so we can do something else with it and ultimately keep it from going down the storm drain.
Next is reduction, which is achieved by providing time for infiltration, evaporation or uptake by vegetation. Simultaneously, we have improvement as pollutants are reduced by filtering, settling, plant uptake and chemical breakdown when stored in the structure.
We can see all this in action by observing a structure like a rain garden during a rain event. Water will be directed into the depressed area and hopefully collect a 1-inch rain event from whatever source it's meant to handle (maybe a roof or driveway). When stored, it will start infiltrating into the soil and being wicked up by plants or porous debris, like mulch.
Cleaning is had by filtering from the soil, settling of debris suspended in the water, and uptake of otherwise polluting nutrients by vegetation. When all's said and done, entering runoff may never leave the garden or it may spill over the edge at a slowed rate and cleaner than prior.
All this, mind you, is achieved by merely a properly sized depression in the ground with some functional and pretty plants. Similar effects can be seen if you reroute a drain spout into your grass or if you install a rain barrel. Planting a tree in your yard also dramatically reduces runoff and greatly improves infiltration rates.
Managing stormwater on your property doesn't have to be complex and might be achieved from some simple renovations. Feel free to reach out to our office or me to learn more.
Chris Gass is a MN GreenCorps member serving at the Carlton Soil and Water Conservation District and focusing on stormwater and urban forestry. Reach him at 218-384-3891 ext. 5. Information on the SWCD can be found on Facebook and at carltonswcd.org.