Saw your other post - will comment here. Did the NRCS help you with a design? I asked them for help and within two days they gave me an outline based on topography, amount of dirt to construct the dam, spillway location, emergency overflow, and ideas for discharge pipe sizing. The quote per acre doesn't mean much - the contractor needs to know "how much dirt" to be moved. My contractor was very familiar with the NRCS's designs and punched his calculator based on the yardage. Hope to break ground in a few weeks.