Publication Summary

The Environmental Investigations and Laboratory Services Program of Ecology monitored ground water quality for one year at a 12-year-old dairy lagoon in Whatcom County. This study was conducted at the request of Ecology's Water Quality Program as part of a larger effort to define the impact of dairy lagoons on ground water quality at several locations in Washington State. The results of these studies will be used to augment existing dairy waste management programs.

The Environmental Investigations and Laboratory Services Program of Ecology monitored ground water quality for one year at a 12-year-old dairy lagoon in Whatcom County. This study was conducted at the request of Ecology′s Water Quality Program as part of a larger effort to define the impact of dairy lagoons on ground water quality at several locations in Washington State. The results of these studies will be used to augment existing dairy waste management programs.

Monitoring wells were installed, and subsequently sampled quarterly. Analytes included chloride, total dissolve solids, total organic carbon, chemical oxygen demand, total phosphorus, ammonia-N, nitrite+nitrate-N, and total and fecal coliform bacteria. In downgradient wells, concentrations of total dissolved solids, chemical oxygen demand, total organic carbon, ammonia-N, total phosphorus, and chloride consistently exceeded upgradient concentrations, probably due to leakage from the lagoon. Also total and fecal coliform bacteria concentrations in downgradient wells exceeded upgradient conditions intermittently. One downgradient monitoring well showed anomalously high concentrations for one sampling event, probably due to localized leakage from the lagoon. The ground water flow conditions near the lagoon were characterized, and the mean ground water flow velocity was estimated to be about one foot per day. Additional monitoring wells are recommended downgradient of the lagoon to evaluate the fate of contaminants and the distance affected.