By: Patrick Troyer, Paulding SWCD
The Paulding Soil & Water Conservation District (SWCD) aids landowners on a variety of best management practices (BMPs) that aid in the preservation of our soil & water resources. The number of practices that can be installed are numerous, but we want to inform the residents we serve of the assistance that is available to them through our office. In a previous installment, we focused on the blind inlet, otherwise known as a French drain, to reduce the amount of sediment, fertilizers, or pesticides moving through a tile outlet. For this week, we will put our focus on a practice known as a grassed waterway. What is it and what does it do? Follow along as we look at this practice.
Grassed waterways are channels constructed to a specific grade seeded to grass or another suitable type of vegetation that are designed to reduce the speed of water traveling through this channel to a speed which will not cause erosion. Typically, this practice is installed areas of a field in which there has been a rigorous flow of water that has led to the formation of deep gullies if they are not fixed. These deep gullies can prove to be a hinderance when trying to cross a field with farm equipment and will get worse over time. According to Ohio State University Extension, grassed waterways are installed to carry the runoff from a field without causing erosion while also allowing any runoff that does occur to be filtered by the vegetation before exiting the field thus aiding in the protection of water quality.
According to the Natural Resources Conservation Service (NRCS), the most common areas in which a grassed waterway applies are slopes where water concentrates as it exits a field or draws between hills (valleys caused by flash floods). Typically, landowners will contact our office with concerns about gullies that have progressively gotten worse over time in their fields. From there, we will run a series of simulations using a program called ArcGIS that will help us to map a watershed to get a preliminary determination of how many acres are draining into the area in question considering things such as elevations and soils. We then run another program which will tell us the amount of water that is being discharged during a rain event, a 10-year storm, which aids in the design process to ensure the grassed waterway will remain stable over time. Following some information gathering in the office, we will head out to the site to conduct a survey using a GPS unit to obtain elevations that will help us to understand what is going on with the lay of the land as water enters the area of concentrated flow. We also take note of any tile blowouts, outlets, and any other observations that may prove to be helpful.
From the survey, we begin the development of a proposed alignment of the waterway through the field and then create a profile drawing of existing elevations to see what is going as water enters the proposed waterway. Considering all the information gathered above, we can begin a determination of how big the grassed waterway will need to be. Not all grassed waterways are constructed to the same width and depth because there is no “one size fits all” solution to design. Other design considerations consider the expected height at which the vegetation that will cover the area will be maintained in both the growing and dormant season in addition to the allowance for an area of a field that is taken up by the waterway.
The one question that many people have is what kind of costs are involved. The important thing to know with costs is that they are very specific to each individual site and depend on the length of the waterway, slope of the land, and the area drained into the waterway. According to OSU, grassed waterways that are engineered typically cost around $1,700 per acre while it would be $30-$40 if only seeding costs are needed. While these costs may be daunting, there are cost-share programs such as the Conservation Reserve Program (CRP) and Environmental Quality Incentives Program (EQUIP) that can help in some way to offset some of these costs. Check with our office or the Paulding County USDA Service Center.
How effective are grassed waterways? They have been shown to reduce the total phosphorous being discharged from a field location due to the increased infiltration of water to the soil resulting in less runoff, according to researchers Fiener & Auerswald. Soil erosion and sedimentation are also reduced because the grassed waterway is slowing the speed of the water down, thus leading to a reduction of these two factors. Grassed waterways are still passable by farm equipment, but it is important to minimize traffic on the waterway if possible.
Where can you get more information on installing this practice and all the good things it can do for you? Stop by the Paulding Soil & Water Conservation District and we will be happy to assist you with this and many other practices that work to preserve and protect the natural resources of Paulding County. Give us a call at 419- 399-4771, email paulding@pauldingswcd.org, or stop by the office at 900 Fairground Drive Suite B in Paulding!
