I have a recently constructed pond and there are several entry points where water from the watershed drains into the pond. At those points there is quite a bit of erosion, especially following heavy rains. I'm planning on putting down erosion blankets and seeding the banks, but at certain points the quantity of water is so large that I don't think an erosion blanket will help. See attached photo.
Was thinking about dumping and spreading a truckload of rock. What are best practices for dealing with erosion at the entry points of a pond?
If you can smooth that area of erosion before the next rainfall event, buy some geotech cloth and put it on top of that swale, then add your rock. Be sure to trench the cloth at the top of the slope so water can only flow across the top. If that the areas of erosion are too wide, then consider building a short terrace at the top of the slope parallel to the shoreline to force water to move in a wide path laterally, then guide it into the pond where you want it, across that geotech cloth. As soon as you can, vegetate disturbed soils with grasses or good groundcover. Once the pond fills, the type of erosion you have will cease.
There are also organic, straw-type erosion mats you can put in place, seed heavily, and minimize erosion.
Teach a man to grow fish... He can teach to catch fish...
As Bob said, we put geotech cloth down and covered it with stone for an inlet and this worked pretty well. Just make sure the soil is well compacted under the geotextile. Water has a way of finding the path of least resistance and we initially had a secondary flow under the textile where we weren't expecting.
I had a main entry point in my biggest pond from a field terrace that I saw was going to be problematic from an erosion standpoint. What I did in that particular situation is I built a 1/10th acre sediment pond. I happened to have the space to do it that would not affect the adjoining agriculture field.
This did two things positive. First it took up some of the elevation change. The new sediment pond inflow is right at the hill's ridge where the terrace comes into the pond so there is no big drop and thus no acceleration of the water flow. The second thing positive it did was act as a filter from the adjacent farm field (that I own) so if dirty water comes in it does not directly deposit in my main pond. Eventually, after maybe twenty years, I may need to have a trackhoe clean out the sefiment pond, but so far it is working great.
I had put down rocks originally from the terrace to the main pond and it was cutting out most of the erosion, but the small sediment pond ahead of the main pond worked great. I have also used it to raise small fish in that I did not mind going into the main pond eventually.
Just another thought if you have the room and resources.