The first step in stopping the erosion is determining why the erosion is happening in the first place. Is the area vegetated? Has the watershed been modified upstream in some way that has increased waterflow through your area? Are cattle accessing the stream freely? There are a seemingly endless number of things that could be going on that are affecting the stability of your streambank. Determine why it is happening and you will know where to start on trying to control it.

Your local NRCS office is probably the best assistance you can get at no charge, but anything that you organize through them usually is very highly-regulated and, thus, comes with a high price tag due to the complexity. It is one of the best places to begin though, even if you do not implement their plan because they will educate you about what is happening with your stream.

As stated previously, before you begin moving any soils around in a wetland, you need to make sure you have approval of the goverment agencies that have jurisdiction over those kinds of activities...DEQ, Army Corps of Engineers, State, etc. Those that follow the laws usually do not have a problem with these agencies, but those that do not may end up with huge fines. Good luck on getting your problem under control.