Erosion can be serious business and as the saying goes an ounce of prevention is worth pound of cure. Here is a good article written by one of UGA’s Water Educators, David Hall describing one preventive measure to help mitigate erosion by using grassed waterways.
Well maintained grassed waterway designed and constructed to carry large amounts of water out of the field slowly.
I saw my EMC meter reader this past weekend and one of his comments to me was that he hated reading irrigation meters. I asked why? “Those roads or paths to the pivot points are ridiculously rough!” I have to agree, I have been down some washed out roads also.
For the most part, farmers each year fill in washed out fields and roads from heavy rains. Do you ever find yourself fixing the same wash year after year? I encourage you to address that issue with a much better alternative. Even with conservation tillage in heavy downpours, there are situations in which water has nowhere to go except create its path downhill taking vital top soil and nutrients with it. Grassed waterways are specially designed and graded channels that are seeded with grass to transport water slowly out of an area to a stable outlet. The purpose and benefits of these structures are many. A well maintained grassed waterway will hold the soil in place and act as a filter. I see too many times where a farmer constructs his on waterway and it fails, leaving him a little upset and saying they don’t work. We have local NRCS, Natural Resource Conservation Service, engineers at our service who would be happy to design and oversee the proper construction whether you do the work yourself or have a contractor.
There are several key design features that must be developed in order for grassed waterways to work. The channel should not be “V” shaped and too narrow for watershed acres to flow. The sides should be sloped and the belly shaped in a parabolic to hold water in the trough. In most cases channel lanes have to be angled in order for water to flow slowly exiting the field. Last but not least, there must be a stable outlet. Some people prefer Bahia grass over Bermuda but regardless of grass, a solid stand is critical. While establishing the stand, fill in immediately and replant grass if rills or washes occur. Fertilization is usually not an issue because we fertilize the grass while fertilizing the crop.
Grassed waterways are the gift that keeps on giving for years and years if properly maintained. Holding soil in place and filtering nutrients while water is flowing out of the field is the main purpose of a waterway but forage can be cut and utilized also.
Here are a few items that can lead to a grassed waterway failure: Making a heavy traffic road in the waterway leads to future gullies. Pick up equipment before crossing! In fact, make a habit of cutting yourself a few feet short. I have personally witnessed a 32 foot wide waterway that has turned into a 15-20 feet wide waterway while continuing to shrink from trying to get that last foot of land planted. Spray parallel to the grassed waterway. I don’t care how good of a sprayer person you are; you will spray into a channel or even worse, forget to cut it off from time to time.
Waterway going straight downhill, low vegetation and being used as a road is a recipe for gullies.
Herbicide kill of vegetation in waterway due to the delayed cutting off of the sprayer before entering a grassed waterway. This will lead to erosion on the edge of the parabolic channel.
Terraces, cover crops and conservation tillage are wonderful conservation tools. There are times though when water can only drain downhill due to the terrain. Grassed waterways are the perfect solution. Perfect, that is, if they are properly designed, constructed and maintained.
Take care of those waterways and they will take care of your valuable land