The water source for most ponds in Ohio is surface runoff from the surrounding land. That area of land is the watershed.
Many activities that occur throughout the watershed will affect the quality of the run-off water, which, in turn, will affect how successful you are in your pond management efforts. Common water quality problems of surface run-off come from improperly maintained septic tanks; industrial pollution; excessive nutrient run-off from crop and livestock production areas and intensively managed turf areas such as golf courses; acid mine drainage; and sedimentation from construction sites, cropland, and timber harvests.
Landowners who own or control the entire watershed for the pond are best able to ensure good quality surface water runoff. When possible, divert poor quality runoff from entering the pond. If diversion is not possible or practical, place grass filter strips between the runoff and the pond.
Watershed size is also an important consideration. Because most of the water for the pond will come from run-off, a general rule of thumb is to have about three acres of watershed for every acre-foot of pond storage capacity. Watersheds that are too large may result in high sedimentation rates, turnover, and storage problems, while watersheds that are too small may not provide sufficient runoff, particularly during drought conditions. The local Soil and Water Conservation District (SWCD) office can assist you with watershed size and land-use determinations.