Hello all.... I have been skimming the posts in search of something similar to the situation I have, but I deemed it may be better if I provide my own post with pictures. Background... Just had this pond built on new property about 6 months ago, and now I am seeing some erosion where the water exits the 15" corrugated exit pipe. I had stacked a large number of rocks around the exit and down the dam, but it appears the water when running with force has sort of sidestepped them. Not sure if I need to fill the washed out area back in with dirt/clay and the put some quickcrete around it, or what the best possible solution may be.... Also, on the entrance of the pipe, do I need to pour some concrete there as well around the pipe? Sorry for the stupid questions but I really do not know much about this. I have attached pics for more detail. Thanks!
As RAH's NRCS link above shows, the anti-vortex plate needs to be 1.5 times as wide as your pipe. I used a 12" wide plate of alumimum bolted over the 8" pipe with stainless all-thread:
