US Fish & Wildlife Service


Date of this Version



Published in Contaminant Report Number: R6/718C /02, 1-19, (2002)


Approximately 600 oil field produced water discharges are permitted in Wyoming by the State’s Department of Environmental Quality's (WDEQ) National Pollutant Discharge Elimination System (NPDES) permit program. Wyoming is one of a few states that allows the discharge of oil field produced water into surface waters for beneficial use by livestock and wildlife. Sixty-six wetland sites receiving oil field produced water discharges in Wyoming were surveyed to determine the percentage of discharges in compliance with NPDES permit requirements and to determine the amount of chronic oil releases associated with these discharges. Separator pits were also surveyed to determine wildlife mortality and to assess implementation of wildlife deterrents. Although limited in scope, this survey of oil field produced water discharges in Wyoming shows that: inefficient oilwater separation is causing a chronic discharge of oil into some of the wetlands receiving oil field produced water; and, over half (53 percent) of the sites surveyed used only flagging to deter migratory birds from oil pits used to skim oil from produced water. Additionally, approximately 85 percent of the oil field produced water discharges surveyed went into ephemeral streams.