Publication Summary

During 2006, the Department of Ecology′s Environmental Assessment Program conducted a screening-level evaluation of ambient groundwater quality conditions in the Moxee Valley, which lies just east of the city of Yakima. During the study, 26 broadly distributed domestic wells were sampled twice for commonly regulated drinking water parameters including nutrients and bacteria, as well as selected general chemistry parameters and metals. This report documents the study findings.

During January and June 2006, the Washington State Department of Ecology conducted a screening-level assessment of groundwater quality in the Moxee Valley. The valley lies just east of the city of Yakima in south-central Washington.

For this study, 26 broadly distributed domestic wells were sampled for field parameters, common nutrients, bacteria, and selected metals.

Concentrations of nitrate-N were found to be higher than the 10 mg/L federal drinking water standard in three wells. Five wells exceeded the primary standard for total coliform.

The highest nitrate-N concentrations (up to 18.2 mg/L) occurred in the lower valley near Moxee City where wells generally exhibited elevated concentrations of total persulfate nitrogen, total phosphorus, total dissolved solids, and conductivity, but little measurable iron or manganese.

By contrast, wells in the upper valley contained elevated concentrations of iron and manganese, but little, if any, measurable nitrate-N or total persulfate nitrogen. Wells in the upper valley also exhibited generally lower total phosphorus, chloride, total dissolved solids, and conductivity values than did wells in the lower valley.

Link to EIM data for User Study ID KSIN0002