I set out to answer the question “what are some interesting new strategies that the agricultural community is employing to address stormwater pollution?”
For the most part, what I found was any number of different takes on the tried and true best management practices that have been promoted for some time now. These include practices such as riparian buffers, no-till and cover crop farming, livestock exclusion fencing, nutrient management plans, etc. Of course, these are all important pieces of the puzzle that should not be overlooked, but that wasn’t really what I was looking for.
My search also led me to the idea of precision agriculture and how farmers are now utilizing technological advancements to improve yield while reducing fertilizer, herbicide and insecticide applications. This too is clearly beneficial from a stormwater standpoint but not quite what I had in mind.
Cascading grassed waterways
There was, however, one relatively new practice for agricultural stormwater management that caught my eye, the cascading grassed waterway. Traditionally, grassed waterways have been installed to stabilize the soil, slow down concentrated flows and greatly reduce soil loss due to erosion.
Cascading grassed waterways incorporate an in-line series of small retention cells, or ponds, into that existing practice. Each of the small ponds fills up with stormwater before spilling over to the next.
This retains the erosion control benefits while also providing additional stormwater storage capacity, promoting groundwater recharge through infiltration and increased nutrient removal through settling and biological processes.
It also provides additional habitat for wildlife. A two-year study of one of these systems that was installed in Maryland indicated a 56% reduction in the amount of water that left the system; a 59% reduction of total phosphorus; a 64% reduction of total nitrogen; and a 65% reduction of suspended solids.
The practice was invented and patented by Samuel Owings, a Maryland farmer in the Chesapeake Bay watershed who also had a background in site development. He designed and installed the practice on his own farm and the above-referenced study was conducted there as well.
Under Owings’ guidance, a design manual was developed, and the system is now being put into practice. There are several examples in Maryland and, in the last couple years, it has even come to Ohio.
Since 2018, cascading grassed waterways have been installed in Allen and Defiance counties, both in northwest Ohio and the western Lake Erie basin. For more information on Samuel Owings and cascading grassed waterways visit: www.highimpactenvironmental.org.
