Pond Boss Forums POND CONSTRUCTION Soil questions Capturing more precipitation

My 3/4 acre pond is totally reliant on runoff. The watershed is too small for the size pond and there are great (3 ft.) flucuations in water level during the year. I want to capture more of the precipitation that falls in the small watershed.

A well is out of the question due to high initial cost and water quality. The property is a former surface coal mine and there are areas where highly acidic water leaches out of the old workings (lower in elevation than the pond bottom).

Anyway, I am thinking of installing a shallow network of plastic drain tile in the non-cultivated field up slope from the pond. That area has a terrace that was built when the land was reclaimed. There are no cattle running there now nor any in the future. I believe tiling the field (about four acres in size) will deliver more ground water to the pond than is getting there now. The advantage to tiling is I can add to the network as I have time and funds.

Please let me know what you think about this idea. Thanks!

Most of the fields in my farm have drainage tile, so I know a little about them. The waterflow part of the discussion that follows, however, is mainly speculation.

If I understand correctly, you're not going to increase the size of your pond's watershed, you are making the precipitation the existing watershed receives flow into the pond faster. A pond is supposed to require a smaller watershed if it is in grasses as opposed to a forested watershed. I believe this is due to grassland having a lower transpiration rate - trees transpirate (draw from the roots and evaporate in the leaves) tremendous volumes of water every day, which is removed from the watershed.

If you tile the fields above your pond and run the tile into it, it seems like this would move water into the pond faster, giving it less time to evaporate/transpirate in the grassland. So I think in theory more water would make it into the pond. How much more I have no ability to quantify, but the wetter/less porous your soils are, the more water would be available to enter the tile to and add to the pond. (Drainage tile in sand would have little effect; tile in soil with lots of clay which does not drain well naturally would have a higher potential for adding signifcant water to the pond).

If you tile, you will be adding at least the potential to introduce more silt into the pond than you have now. My field tiles are 50-75 years old and are the old ceramic, hand-fitted style. They have lots of crack and gaps; as a result, in times of VERY heavy runoff, I can see a plume of sediment entering the pond from the 6" tile which runs into it (to be fair, when there is this much rain, I also have noticeable sediment entering the pond with surface runoff).

The current corrugated plastic tile should have much less sediment entering it, since it is new, has molded joints, and is less prone to cracking (it will collapse if pressure is applied rather than break). The amount of additional sediment going into your pond should be negligable if you use the slotted (holes like this: l) as opposed to holed (holes like this: O) plastic tile.

I dug a 100' trench across my property and and am now diverting all the runoff from one part of my yard through a pipe under the driveway and into the pond. It has helped out a lot as now I am able to maintain full pool about 10 months of the year. I still have to supplement from the well some in the dry times but I only dropped 18 inches last year compared to up to 3 ft in previous years. So if you can divert the water it will help even if only a little as in my case.

Bob