Here is a tidbit from my agronomy days applied to agricultural law: Soil is composed of four solid constituents: sand, silt, clay, and organic matter. The most productive soil is a loam, which contains roughly equal proportions of sand, silt, and clay (and as much as 4 or 5% organic matter). Most of western Iowa is blessed with clay loam and on the riverbottoms with silty clay loam thanks to wind-blown silt particles called loess (pronounced “luss”) left behind by the glaciers after the last ice age. Silt is, by far, the most easily eroded soil component. Hence the need for silt dams and fences to prevent bodies of water from filling up with silt. Structures that catch silt such as dams and terraces have to be cleaned out periodically to maintain their water holding capacity. For instance, when one builds terraces with state conservation cost-sharing money, one signs a maintenance agreement that ensures that the terrace’s design capacity will be maintained. By the same token, because of its erosive nature, silt makes a poor dam material. Earthen dams and terraces must be built of clay, which is a much smaller particle, but which has high particle adhesion.
It has been my experience as a farmer that nothing is harder on dams than cattle. In fact, if you build a dam with conservation cost-sharing assistance, you will be required to sign an agreement requiring you to fence cattle away from the dam and allow grazing of the dam only under limited circumstances. It is also for this reason that conservationist are encouraging farmers to fence cattle away from river banks.
My adversary suggested in his letter that a dam is higher or longer than the original easement signers contemplated. Because there is a fence across the dam, I think it is safe to say that the dam height has not changed at least since the fence was put in. In addition, the original dam height may have been too short. When I worked for the Soil Conservation Service we used to call home-made under-capacity dams (which seemed to be common in the 70’s) “doodle dams” because they would be washed out by the first heavy rain. Any structure designed to retain surface water should be designed with the capacity to hold the runoff from a Q-25 storm. The parties could have the Natural Resources Conservation Service (NRCS) evaluate the dam to see if it is sized appropriately for the watershed it serves. There may even be cost-share money available for the structure. But even without that, the clear purpose of the easement was to protect the clients’ pond from silt runoff and the current size of the dam no doubt reflects the wisdom of the years with respect to the sizing of the dam, regardless of the size speculated in the original easement agreement.
