Meadowlark
In my past experience with the NRCS, it is generally less expensive to add fill to the top of the dam to gain additional storage than to excavate material from the reservoir.
Exceptions: 1)additional permits may be required to add height to the existing fill. 2) feasibility of raising fill; property boundaries, exiting spillway, etc.
Remember: One acre ft. of muck is equivelent to 1613 cubic yards of material! The cost to excavate that much material could approach or exceed $2.50 per cubic yard. (Depends on your location and Contractor)
Example: You would only have to raise YOUR 2 surface acre pond 1/2 ft. to equal that much excavated material. You be the judge.
Options: If your wanting to excavate (track hoe), CONCENTRATE the borrow with the creation of habitat as a goal. ( In Wyoming and Nebraska a minimum 10 ft. of depth is recomended over 1/4 the pond area to minimize winter kill.
Hope this helps with your decision,
Ed
