Yesterday I posted a picture and a little description of an area on our farm with a bit of erosion going on. Right now it is not a "major" problem (as some pointed out), but that doesn't mean that eventually it won't move from the stage you see in yesterdays post to the stage you see in the picture on the left. The picture on the left is not from my the land we are buying, but I would consider it an unacceptable waterway. It just does not have to be like that.
Eventually if nothing was done, and if the place would continuously grazed (not something I'm going to do) the small cut in the ground could turn in to something like is pictured in the right. There is enough water draining down to cause that sort of damage. After time things could get even worse. In fact (and I'm sorry I don't have a picture of it) if you were to follow that waterway/gully down to where it meets the woods you will see that I'm already beginning to lose part of my pasture from some erosion in the form of a big washout. It is easy to see that the washout is growing and I would really like to help stop that before it goes any further.In fact, I am not the only one who has realized it was a problem. If you were to head out to the land to day and look down in the washout you would see that at some point (not to long ago) after they took down the exterior fencing they threw it in the washed out area to help prevent more erosion. I am no expert, but I think we can come up with something better than that!
My short term goal is to get someone from the local extension, NRCS, or some other help out here to talk about different seedings that I can do. Also, we have talked about the possibility of mowing and then baling the switchgrass on the land because it could take awhile for the rural fire department to work their way down the list to our names. In that case I had considered the possibility of using some of those bales as filers in the washout. Something to stabilize the edges, but slightly more natural than rusty woven wire.
Next we want to use managed grazing (possibly with some ultra high stock density) to return some nutrients to that area of the land. With the help of our cattle hopefully we can add some more organic matter to the waterway. This will not be an area that we can graze in all conditions, but it is something we can manage as part of the whole and to help improve the land.
In the long run this would be a natural place to put a small pond. I'm not sure how big of a pond this water shed could support, but it would at least be enough to supplement our livestock water. We would not all our livestock access to the pond, but would rather pump out of it (or use gravity) in order to provide water. This is in the long term, but is a possibility. Besides, it would make for a great view from the house!
Those are just a few of my initial thoughts and things that I gleaned from the great comments yesterday. Being a "grass farmer" is my goal, so I want to make sure I am taking care of all the areas on the farm as best as possible. Next time we are out there I will make sure I get a picture of the washout...
The way I see it, the type of erosion you (and also myself) are trying to prevent and repair actually need to be thought of as two different types of damage (or potential damage).
ReplyDeleteYou have the area of drainage erosion in the pasture, and you have the washout (or head gully) near the edge of the pasture or wooded area.
The channel forming in the pasture is being caused by the velocity or high flow rate of the water runoff, and the washout is being caused by the total volume of water draining off of the pasture.
The erosion in the pasture can be lessened by reducing the velocity of the water, i.e. spread the water over a greater area and slow it down by smoothing out the slope with high density grazing, and/or build check dams in the drainage area with staked bales of hay to slow the flow rate of the water.
The erosion at the head gully is the more difficult problem and will probably take more work and thought. Even if the flow rate of the water is slower due to the efforts of your grazing distribution and/or any check dams, the total volume of water over the head gully will be almost the same as before (unless the rate of water infiltration can be increased significantly).
Erosion at the head gully is of a greater magnitude because the water is funneled over the upper edges creating a waterfall that forms into a soil/water slurry which then splashes against the banks of the gully, scouring more and more soil from the gully until the sides are undermined and the bank collapses. Each time the bank collapses the head of the gully advances farther upstream into your pasture.
One of the reasons for a "junk ditch" is to try to slow down the erosive scouring in washouts. But, piling junk in a washout will only "catch" a portion of the soil being scoured, it won't stop the scouring completely.
Stabilizing the banks of the head gully by either stopping the collapse of the bank, or "catching" the collapsed bank before it can wash away seems like the best way to solve the scouring problem. I've seen articles (and have personally tried) that describe a technique which involves cutting and laying material like tree branches at the base of the bank, covering it with woven wire, then holding down the wire against the bank by either staking the wire down or stacking rocks along the base of the bank. The structure serves to reduce splashing,(which reduces the scouring effect), and it catches soil from any collapsed banks. I would tend to believe that it would have to be "reinforced", or have layers of new material added after every major storm event. Until the bank is stabilized, it will be difficult to get any kind of vegetation established.
Controlling water flow can be a tough nut to crack, just like trying to push a rope. You push on one end and you can't make it go where you want it to go.
Rich, good thoughts. I think much of what you say is the approach we are going to take.
ReplyDeleteOne key I think will be to try and build the organic matter in the waterway so that there will be a bit more absorption rather than run off.
Really I don't think there is really that large of watershed for this area and it isn't overly steep, so I think if we take positive steps now we can fix the problem for the future.
That being said, the head gully will be a chore!
After re-reading my comment, I noticed that I used the term "head gully" when I really meant to say "gully head".
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