Infiltration and water quality impacts associated with wastewater ponds

The Texas High Plains area during the past 25 years has developed a large cattle feedlot industry that is believed to be a polluter of the surface water and groundwater supplies. It is believed that a natural liner can be formed when manure is placed on top of soil in an agricultural wastewater lagoon. The research contained in this project focused primarily on the infiltration characteristics beneath an integrated facultative pond (IFP) constructed near New Deal, TX. Samplers were placed transversing the cross section of the IFP and the water permeating the soil was monitored for a period from July 27, 1997 to May 30, 1999 and the permeability of the pond was determined. Results show that the pond attained permeability less than the Texas Natural Resources Conservation Commission (TNRCC) regulations of 1.0 x 10" cm/sec. Additional analysis was conducted to determine what the packed manure layer thickness was at the bottom of the pit. This packed manure layer ranged in thickness from 5 cm to 10 cm in most cases. Additionally, the water that infiltrated into the underlying groundwater supply was monitored for wastewater constituents. This monitoring showed that nitratenitrogen levels were within the limits established by the National Primary Drinking Water Standards (NPDWS).