E:
Earth Day: Selected Resources - Science Reference Guide - Finding guide from the Library of Congress, Science Reference Section [U.S. Library of Congress (LOC)]

H:
Hydrology Technical Group - Carries out a variety of research on groundwater movement and the effects of dams [U.S. Department of Energy (DOE), Pacific Northwest National Laboratory (PNNL)]

Hydropower Program - Reviews efforts to improve the technical, societal, and environmental benefits of hydropower [U.S. Department of Energy (DOE), Idaho National Laboratory (INL)]

M:
Managing water in the American West - Science and Technology Program. [U.S. Department of the Interior (DOI), Bureau of Reclamation]