I am having a new pond constructed. It will be partially excavated, but with a small dam. It will have a maximum depth of 8 or 9 feet. It is probably about one acre. The main water source will be rain over about a ten acre area supplemented by a small wet-weather stream that flows during heavy rains. I am concerned that the water source may be marginal. I also have a drainage ditch about 250 feet from the pond site. Two ditches enter the main ditch in a catch basin, which empties through a corrugated pipe. I thought it would be a good idea to divert some of that water to the pond. The top of the drainage ditch is about one foot above the full-water level of the pond. My idea is to install a 6" or 8" pipe from the existing catch basin to the pond. I would install a slide gate or stop gate to block the corrugated pipe outlet. The layout of the catch basin is here:
http://www5.vetmed.auburn.edu/~branch/images/pond/HS_P8300021Labelled1.jpg . Finally my question: If I run the pipe from the ditch to the pond, should I stop the pipe at the pond's full-water level or go a little farther and stop it at about two feet below the full-water level? If I do that, then I would have about three feet of head when the ditch is full and the pond is empty. My rough calculations give a flow rate of about 300 or 800 gallons/min for 6" and 8" pipes respectively. The contractor wasn't sure it would do much good to extend the pipe's outlet below the full-water level. But it seems to me that it would--until the pond gets close to full.
Question: Is this general idea worth doing? And if so, am I correct that extending the pipe two feet below the full-water mark is going to increase the head and the flow?
Some other images of the pond construction are here:
http://www5.vetmed.auburn.edu/~branch/images/pondOne image at
http://www5.vetmed.auburn.edu/~branch/images/pond/HS_P8270018.jpg shows the view across the pond; the dam is to the left. The excavation is not completed on the far side. A distant view of the whole site is at
http://www5.vetmed.auburn.edu/~branch/images/pond/HS_P8280009.jpg . The dam on the far side, and has been partially covered with top soil. The tree behind the tailgate of the truck is the same tree that was behind my wife and my dog in one of the other images.
Any suggestions would be appreciated.
Thanks,
Charlie
