I just recently aquired property behind my house (20 acres) that has a deeeep ravine, the creek sides are 12-15 ft tall. I had the NCRS man take a look and he told me that the ravine drains 320 acres and it was on the verge of being a flood control project. Said I could get done for 250,000 lol!! I decided to build a little pond instead. Is he right or do I need a second opinion?