Hey Team,
Long time lurker, first time poster. In 2018, I purchased a 90 acre farm in northwest Middle Tennessee. The property runs the length of a ridge that falls off to two spring fed creeks on either side. The land was owned by an older gentleman prior to me who let a lot of the cleared areas grow up over the years for hunting. At some point in the distant past, the property was cleared and terraces were cut into the hillsides to allow for crop production on the hillsides with minimal erosion. Those terraces have directed water flow to two main areas over the course of the past 50+ years and have failed in places, creating two areas of wild and unruly gullys (I'll take some pictures and post later today).
My question: as a means of slowing water and correcting erosion, would a pond (or series of ponds) in these areas be a good plan?
Thanks in advance for any help
Is nothing growing here? Maybe get some fast growing grasses for the time being, then get a pro dirt guy in to give you best options.
A pond sounds like a great idea for a lot of reasons. I dont think anyone here will say anything other than "it depends, but yes"
In geology, there is a concept called "base level" that defines the lowest level of an erosion process.
For example, if sea level dropped 100', then every coastal river in the U.S. would immediately start down cutting through its existing bed. This would occur even though each river would still have the exact same amount of water flow.
I will give an example for your situation - of course my hypothetical numbers will be wrong, but consider the concept.
If the land at the top of your ridges is 90' above the level of the stream in the bottom of the ravine, then any water runoff "sees" the energy of a 90' drop. This is a lot of energy to sustain continuous erosion.
However, if you could build some chuck dams and create little ponds along every 15' of elevation drop, then you would substantially reduce the erosion. Every bit of water would now only "see" a 15' drop, which significantly reduces the erosive energy. (The process is NOT additive.)
You just need to create a pool of water that has a level surface, to change the erosive energy.
Once you slow down the erosive potential, then you can cut some terraces, plant cover, etc., whatever is best for your particular circumstances.
Further, if the two spring-fed creeks on the sides of your high ground are "tumbling" creeks, then they are still enhancing the erosion of the gulleys above. If you want to go big, then a pond on these streams would actually reduce the erosion of the gulleys. However, now you start to reach the level of well-engineered dams and properly sized spillways to build a pond in that situation.
At the other end of the problem, repairing your terraces on the high ground may be your most cost-effective solution. A properly built terrace has the crest at the exact same topographic level for the entire length of the terrace. Consider the water from a 1" rain storm going over the entire length of an 1100' long terrace. Then consider that exact same amount of water going through an 8' gap in the terrace. A properly constructed terrace is essential to hold the topsoil on any tilled field that has even a little bit of slope.
Hope that helps you some.
Good luck,
Rod
Nice explanation Rod! I would like some clarification, for curiosity's sake...
"The process is NOT additive" GIVEN the ponds or terraces are in place, correct? As it would seem to me, without the chuck dams, the erosion power would build as the water traveled down the hill gaining velocity all the while.
Am I on track?
You are exactly on track!
My statement, "The process is NOT additive" is ambiguous. (I see that it could be read that the "process of creating small dams" is not additive.)
I should have said the erosive energy is NOT additive.
A 90' drop is >>> greater than six 15' drops - even though the math is the same. The physics is not the same.
Any time you can break the water flow chain with a level surface of pooled water, you are reducing your erosion.