Land use in the watershed above the pond should be considered when selecting a site because the quality of the fish community in the impoundment will reflect the quality of the watershed. Active erosion may fill a pond with sediment in relatively few years. Land with grass cover generally has less erosion and is desirable. Land with row crops can produce erosion and sedimentation problems if soil conservation practices are not applied and if a grass buffer area is not developed. Cropland can also contribute toxic materials such as pesticides and excessive nutrients in the form of fertilizer, which can lead to fish kills and aquatic vegetation problems.