Grassed waterways help with several issues


As you drive through the country, you might have noticed some grassed channels peeking through the corn or soybeans this year. Or perhaps you have noticed these areas of grass still standing after harvest. Maybe you wondered why the farmer doesn’t keep those grassed channels mowed down nice and neat?

Some of these channels are what the Natural Resource Conservation Service calls “Grassed Waterways.”

A grassed waterway is a constructed channel shaped to a set of required dimensions and then covered with vegetation. NRCS often uses grassed waterways to control the conveyance of water across a crop or pasture field to help minimize possible erosive effects of the water.

As water travels across the ground, it can pick up small pieces of loose soil. The greater distance that water runs across the ground, the more particles of soil it can carry with it. Also, as water deepens and channelizes, it increases in speed and force. With an increase in speed and force, this water can loosen and carry larger soil particles with it, along with a larger number of particles at one time.

Over time, whether it is a few years, or even a few heavy downpours in one growing season, the removal of soil will form a channel called a gully.

There are many reasons that farmers or livestock owners would want to control gullies in their cropland or pastures. As these soil particles leave their fields, they often carry with them nutrients that have been applied to improve crop or forage production. As these nutrients leave the field, they are no longer available to enhance row crop or grass production. Given the cost of nutrients, this can also equate to dollars washing out of crop fields and pastures.

Loose soil particles and nutrients leaving fields and pastures can also have an impact on water quality. Soil particles and nutrients suspended in ditches and streams leads to cloudy water, and as water slows or changes direction, the soil particles can drop out of the stream flow, and lead to a buildup that can change the direction or even clog streams or rivers.

Grassed waterways can often help lessen or resolve these problems. Waterways are constructed to slow down and spread out water as it travels through lower areas, which decreases the speed and force of the water. This decrease reduces the amount of soil and nutrients that are loosened and carried off the site. Any soil particles that are being carried through the grassed waterway will begin to drop out of the water flow as it slows, which traps the soil in the vegetative cover of the waterway and prevents it from entering a waterbody. For this reason, it is also important to keep grasses in waterways taller to withstand the speed and force of the runoff and trap as much sediment as possible.

If you have an eroded area in your crop field or pasture that you have noticed getting deeper or wider or happen to find an area as you harvest this year, perhaps you should consider installing a grassed waterway. The Natural Resource Conservation Service can be a source of technical information concerning this practice, and at times, can also provide financial assistance in establishing this practice.

If you are interested in learning more about grassed waterways and how they can help your farming operation, contact the Brownstown Field Office at 812-358-2367 ext. 3.

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