I expect there are a variety of plants that would provide low ground cover. Bermuda grass comes to mind. The county should be able to help you. There used to be county extension agents that provided help with such things, but I think they may have been replaced by something else, at least in some States. There are also master gardeners in some areas that provide advice. The slope of the banks would have a bearing on what would be suitable, also soil type, moisture, shade, and other things.