Sometimes someone will offer you a theory. It is up to the thinking person to weigh the merits of what that person says, in an attempt to see if it will hold water. I have a couple theories swirling around in my head this morning. I am wondering myself if they will hold water.
A year and a half ago, I hired a bulldozer and operator to push a dam up here at Gilly Hollow. It was at the bottom of a bowl shaped depression that often held water during rainy years. I kept having the fellow move more dirt until I estimated the depth would be around fifteen feet, once it filled with water.
Last year was a very dry year. We here in Iowa suffered through a sever drought. I'm not certain if they've called that off and we are officially out of drought conditions, but if the mud out here is any indicator, we are. In any event, last year that pond filled to about the half way point, and then over the course of a couple days, the water percolated back into the ground. It didn't appear to be holding water, at least in any permanent manner.
It was so dry last summer, even the mud dried out and there was little more than a dry hole off the side of the lane. When my son visited from Florida, he took great joy in driving my Jeep into and out of that hole. The steep sides made for some fun while climbing out; but alas, no water.
The month of February this year was a fairly wet month. We had a few different snow storms which packed into a hardy layer of snow and ice. It melted fairly quickly over the course of a few days in March. I was pleased to see the pond almost full. I hoped it would stay that way.
My plan, if it does eventually hold water is to design and build an aeration system in the pond, and stock it with fish. There is something alluring to me about having the ability to walk a short distance down the lane and catch supper. We intentionally picked a spot for the pond that was entirely fed from the runoff of grassy areas. The water should be fairly clean and silt free.
I was pleasantly surprised the other day when I walked down the lane to take a picture of the pond to send to my son. There was a pair of ducks swimming around in the pond. A hole, some water, some ducks; we appear to be making some progress.
I have been monitoring the level, to see if it is indeed going to hold water. It is down about 3 feet from its highest level, but is holding water longer than last year at least. I think the hydraulic pressure of the water in the pond helped pack some of the soil at the bottom, which remained fairly loose last year. If we continue to receive rainfall over the next couple months, and the pond stays near full, I am hoping the weight of the water will pack that soil even harder.
I can't imagine that the builders of the various ponds I see in the area had to do anything heroic to seal their ponds. I looked into the science of packing bentonite into the bottom of the pond to seal it, but the cost was more than I wanted to bear. Did others have to seal the bottom of their ponds?
Several years ago, when we were digging the foundation for our tower, I made the mistake of calling the dirt coming out of the hole clay. I was told in no uncertain terms, that it is not clay, but highly compacted red earth.
The top part of our property is a Paleozoic plateau. South Tama County was the southern terminus of several of the great glaciers. The advancing, then receding glaciers carved out the deep ravines and created the creeks and rivers in our area. This dynamic caused the steep variance in terrain found here. And like much of the south county, our property is a series of hogbacks and ravines. There is over one hundred feet of vertical variance from the top of the property to the bottom. And that top part which was not scraped by the glaciers is red earth; highly compacted red earth.
So, will it hold water? Only time will tell. It has been raining most of the night. The frost came out of the ground with that rain. Once again there is a layer of mud on the lane, but with a 70 degree day in store, it should dry out quickly. I hope the water flowing down that grassy hill will fill the pond to the top of the dam. There is more rain forecast for tonight. I'm excited, can you tell?
Until next time-
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In to the Wind and this column are copyright 2005 - 2013 Mike Gilchrist. Readers, feel free to contact me at firstname.lastname@example.org via email, or write to me at P.O. Box 255, Toledo, IA 52342.