The Bureau of Reclamation Denver just posted two job openings with the Water Resources Engineering and Management group, at the Bureau of Reclamation's Technical Services Center in Lakewood.
https://www.usajobs.gov/GetJob/ViewDetails/513554000
https://www.usajobs.gov/GetJob/ViewDetails/513554500
They are targeting MS or PhD students with an interest in western US water issues, a strong science or engineering background, familiarity with modeling and/or flood hazard analysis, and data analysis.