How to avoid losing nutrients with water flow.

I am digging a pond that will collect water from three sources, some wet weather springs, some runoff from a ditch along side a gravel/dirt road going up a 200 ft. hill, and a swale collecting water from about a 3 acre hill (wooded with rock outcroppings). The inflow is heavy from November until June. From June to November it is dependent on periodic rainfall. The pond is going to be roughly 200 ft long and maybe 40 ft wide at the widest point. From the inflow, the first 30 feet or so, I ran into large rocks, (bedrock) at about 4 ft deep. Past that point I am able to dig down about 6 ft. I expect to have another 4 ft above this 6 ft depth when the dam is complete. Initially I was planning on the inflow being on one end and the outflow on the other end. However, I read somewhere that a pond that gets a lot of water flow will lose many of the nutrients that fish need. So I am considering moving the spillway toward the end of the rock shelf closer to the inflow, maybe 1/3rd of the length of the pond from the inflow. Would this reduce the water exchange in the deeper end and reduce the loss of nutrients?

Mike Schroer : I would worry a great deal more about the runoff into my pool slowly filling in my pool from the bottom up and the slumping of the side walls of my pool
creating a wetland around the border of the pond !

If possible at all, consider maximizing your water flow channeled through/along the ditch on the side of the road. This will create a buffer zone allowing sediment to
settle out along the way to your pond, and giving you a partner in maintaining the condition of your water supply route to your pond !

A small buffer zone of Cattails, Rushes, and cold weather hardy Bamboo (or at least that is what I've been told here !) at inlet, and at the dam spillway should take care
of slowing Flow Rates, protecting your dam and reducing the loss of nutriments ! Hope this Long distance Air-castle will work with what you face out there in the 'Real
World ' For the Future / Good of the Crafts ! Be safe, keep warm ! As always, your comments and questions are solicited and are Welcome PYRO - LOGICALLY Big AL !