Publication Summary

Ground water quality was monitored at four dairy waste storage ponds in Washington State: two in Whatcom County, one in Yakima County, and one in Lewis County. The purpose of the monitoring was to assess whether leakage from ponds affected ground water quality.

Ground water quality was monitored at four dairy waste storage ponds in Washington State: two in Whatcom County, one in Yakima County, and one in Lewis County. The purpose of the monitoring was to assess whether leakage from ponds affected ground water quality.

Each pond system was underlain by shallow ground water. The ponds varied in age from new to nine years, and construction, e.g., one-stage and two-stage pond systems. Ground water monitoring networks, consisting of upgradient and multiple downgradient wells, were installed at each pond system. Sampling frequency varied from monthly to quarterly. Analytes included chloride, total dissolved solids, total organic carbon, chemical oxygen demand, total phosphorus, ammonia-N, nitrite+nitrate-N, and total and fecal coliform bacteria. Monitoring periods ranged from one to three years. Leakage from three of the four ponds affected ground water quality. No leakage was detected at the fourth pond (Lewis County).