Thanks for the feedback. I do believe that I will need to downsize that watershed by building a berm or two to eliminate some of those acres from going into this pond or it would back up on the neighbor's property.
I appreciate the info on an island and the sediment pond.
Hi! Keep in mind that it�s not really the watershed size that will keep water off your neighbor, rather it�s the elevation of your pipe or spillway the will keep water off your neighbor. Example: If your spillway crest is at 1500� elevation and your property line in the upstream channel is at 1499�, you will flood water over the property line regardless of your watershed size, it just might take a little longer to do so with a smaller watershed.
As a rule of thumb, when laying out a pond, I keep the top of the dam elevation (which is usually about 2� above the spillway elevation, but can vary based on the amount of flow your spillway is designed to handle) at or below the property line elevation. That way I never have to worry about flooding the upstream neighbor. In the example above, I would set the top of dam about 1498.5� or so.
Good luck!
