How much freeboard do you have on your dam at full pool? What is your dam width at this water level?
I'll try to measure it tonight, but here is couple of pics of the dam the water can come up about another foot. The pics show that we can drive a truck across the dam.
One acre pond built in 2007.
Stocked: Mar 2010 500 BG and 250 Shellcrackers Mar 2011 25 LMB and one bag of FHM
I was refering to the area where the back of the dam starts to lope downward. FYI - Longer runs will slow the water due to friction as will sharp bends, so larger pipe sizes are beneficial. The head on your pipe (vertical difference in elevation between the source and the outlet) will also affect flow and pressure, but dips and rises in-between will not. The water gains pressue on the way down equal to what it loses on the way up. Think of a garden hose full of water with both ends held up at the same elevation. If you lower one end, the water flow will not depend on the elevations in between, just on the difference in the elevation at each end. The same is true with water that is being pumped.
I was refering to the area where the back of the dam starts to lope downward. FYI - Longer runs will slow the water due to friction as will sharp bends, so larger pipe sizes are beneficial. The head on your pipe (vertical difference in elevation between the source and the outlet) will also affect flow and pressure, but dips and rises in-between will not. The water gains pressue on the way down equal to what it loses on the way up. Think of a garden hose full of water with both ends held up at the same elevation. If you lower one end, the water flow will not depend on the elevations in between, just on the difference in the elevation at each end. The same is true with water that is being pumped.
I was thinking that on the top there would be less chance of erosion from the water running down the side into a new trench.
One acre pond built in 2007.
Stocked: Mar 2010 500 BG and 250 Shellcrackers Mar 2011 25 LMB and one bag of FHM
I would guess that if the bottom of your trench is above the full-pool level, then the risk of a problem is low. I would still tamp down the backfill in layers so it does not provide a weak spot in the dam.