Hank Johnson

Hank Johnson is a hydrologist with the U.S. Geological Survey at the Oregon Water Science Center in Portland, Oregon. His research interests include water-quality trends in surface water and groundwater, environmental tracers, and springs as windows to groundwater systems.



M.S., Environmental Science and Engineering, 1996
Oregon Graduate Institute of Science & Technology
Hillsboro, Oregon

B.S., Geological Sciences, 1992
Virginia Polytechnic Institute & State University
Blacksburg, Virginia


Research Interests

Trends in water-quality of surface water and groundwater

Environmental tracers

Springs as windows to groundwater systems.


Current Studies

Surface Water Trends Team, National Water-Quality Assessment Project (NAWQA)

  • A multidisciplinary team is working to quantify trends in water quality in streams across the conterminous United States. Constituents of interest include nutrients, carbon, chloride, sulfate, pesticides, fish, invertebrates, and algae. We are using an unprecedented compilation of water-quality data from hundreds of federal, state, local, and tribal entities to generate the most complete National assessment of trends in water-quality conditions since the passage of the Clean Water Act in 1972.

Enhanced Trends Network (ETN), National Water-Quality Assessment Project (NAWQA)

  • The goal of the ETN project is to character short-term changes in groundwater quality to provide context for changes observed in decade-scale trend assessments. The study in the Umatilla Basin of Oregon is one of eight intensively monitored sites in the United States and is providing information on short-term variability in aquifers comprised of the Columbia River Basalt group and overlying sedimentary material. The location of the Oregon ETN coincides with a state-recognized groundwater management area for elevated nitrate concentrations. The study is providing insight into the sources of water in deep basalt aquifers, travel time and susceptibility of mid-depth wells completed in sedimentary fill, and connectivity between the Columbia River and shallow, near-river wells.

Understanding changes in spring discharge to short- and long-term climatic changes in southeastern Oregon

  • Springs are an important resource for grazing animals and wildlife in southeastern Oregon, where precipitation is seasonal and spatially heterogeneous. This study seeks to identify common causes of interannual spring variability on lands managed by the Bureau of Land Management (BLM) to help them prioritize individual springs and regions for long-term conservation.

Groundwater resources of the Harney Basin, Oregon

  • The groundwater-flow system in the Harney Basin is poorly understood, and the ability of the resource to sustain existing uses and to accommodate additional development is not well known. In addition, substantial uncertainty exists regarding the extent to which groundwater development will impact surface-water resources and holders of senior surface-water rights throughout the basin. This study seeks to improve the understanding of the groundwater hydrology of the area and to provide stakeholders and water resource managers with information to make informed groundwater-resource decisions.

Characterizing the timing, stability, and sources of water to the Willamette River using stable isotopes

  • Climate of the Willamette River Basin is characterized by warm, dry summers and wet, cool winters; 75% of the annual precipitation falls between October and March. During the wet season, rain is the dominate form of precipitation below about 1,000 m and snow dominates above about 1,500 m. Late summer flow in the Willamette River and its tributaries is dominated by precipitation that fell at least 6 months prior. The timing, stability, and sources of water to the Willamette River and its tributaries during summer low-flow periods is the primary question being investigated in this study.