Tanja N. Williamson, PhD
Soil-water scientist experienced in natural and human-affected systems, including links with vegetation and landscape dynamics. Research interest spans landscape and water-resource effects of agriculture, mining, development, and climate change. Published research supported by OSMRE, USDA, NSF, USEPA, USGS, state agencies, and universities.
Recent and ongoing research includes:
- Hydrologic modeling of mixed land-use watersheds
- the importance of land-cover change to streamflow magnitude, variability, and seasonality
- developing decision-support systems that inform resource managers
- Incorporation of soil-physical data into hydrologic modeling
- Comparison of lab and field measurements to modeled soil properties
- Sensitivity of hydrologic models to changes in soil properties
- Simulation of hydrologic response from landscape reconstruction
- Temporal variability of soil-water storage and movement
- Agricultural resilience under projected climate change
- Delineation of ephemeral and intermittent streams in Appalachia
- Conservation management in agricultural landscapes
- Identifying sediment source
- Linking soil-water storage with the stream environment
- Extent and characteristics of tile-drains (sub-surface agricultural drainage)
Education
Ph.D. Soil and Water Science (Pedology), University of California, Riverside, 1999
M.S. Earth Science (Geomorphology), University of California, Riverside, 1995
B.S. Geoscience, The Pennsylvania State University, 1992 (includes PSU Field Camp)
Professional Experience
U.S. Geological Survey
- Research Hydrologist, Kentucky Water Science Center (2010 to present)
- Hydrologist, Kentucky Water Science Center (2006 to 2010)
Adjunct Assistant Professor, Department of Plant and Soil Sciences, University of Kentucky (2016 to present)
Quinte Conservation, Belleville, ON, Canada (2006)
Loyalist College, Belleville, ON, Canada (2004-2005)
University of the Pacific, Stockton, CA, Geosciences (1999-2004)
Science and Products
Using machine learning to map topographic-soil & densely-patterned sub-surface agricultural drainage (tile drains) from satellite imagery
In the mid-1800s, tile-drains were installed in poorly-drained soils of topographic lows as water management to protect cropland during wet conditions; consequently, estimations of tile-drain location have been based on soil series. Most tile drains are in the Midwest, however each state has farms with tile and tile-drain density has increased in the last decade. Where tile drains...
Agriculture Best Management Practices: Quantification of In-Stream Phosphorus and Sediment Storage and Transport - Linking Land Use and Landscape Best Management Practices with Downstream Transport in Great Lakes Restoration Initiative Priority Watersheds
As part of a coordinated effort with University of Minnesota (UMN) and US Forest Service (USFS), USGS will conduct sediment and phosphorus source tracking in two agricultural watersheds -- specifically corn and soybean production -- of Black Creek and Plum Creek, tributaries to the Maumee and Fox Rivers, respectively.
Environmental Effects of Agricultural Practices
As agricultural land in the Minnesota River Basin is retired, tile drains are removed or broken and riparian corridors are planted to reduce runoff. Early studies saw decreased sediment and nitrogen and improved biological indicators but no significant changes in phosphorus. This project continues to investigate the linkages between riparian buffer extent, age, and continuity; stream water; and...
Simulation of Soil-Water Availability
How much water is stored in the soil? Does agricultural management affect this? Will this change if temperatures increase and plants need more water? In order to answer this question, we have focused on the differences in soil physical properties under four land management types (forest, pasture, traditional agriculture, and conservation agriculture) and whether these differences effect how water...
Unmanned Aircraft Systems
The USGS Ohio-Kentucky-Indiana Water Science Center has become a regional leader in using Unmanned Aircraft Systems (UAS), also known as drones, for mapping and hazards analysis.
Science and Products
Using machine learning to map topographic-soil & densely-patterned sub-surface agricultural drainage (tile drains) from satellite imagery
In the mid-1800s, tile-drains were installed in poorly-drained soils of topographic lows as water management to protect cropland during wet conditions; consequently, estimations of tile-drain location have been based on soil series. Most tile drains are in the Midwest, however each state has farms with tile and tile-drain density has increased in the last decade. Where tile drains...
Agriculture Best Management Practices: Quantification of In-Stream Phosphorus and Sediment Storage and Transport - Linking Land Use and Landscape Best Management Practices with Downstream Transport in Great Lakes Restoration Initiative Priority Watersheds
As part of a coordinated effort with University of Minnesota (UMN) and US Forest Service (USFS), USGS will conduct sediment and phosphorus source tracking in two agricultural watersheds -- specifically corn and soybean production -- of Black Creek and Plum Creek, tributaries to the Maumee and Fox Rivers, respectively.
Environmental Effects of Agricultural Practices
As agricultural land in the Minnesota River Basin is retired, tile drains are removed or broken and riparian corridors are planted to reduce runoff. Early studies saw decreased sediment and nitrogen and improved biological indicators but no significant changes in phosphorus. This project continues to investigate the linkages between riparian buffer extent, age, and continuity; stream water; and...
Simulation of Soil-Water Availability
How much water is stored in the soil? Does agricultural management affect this? Will this change if temperatures increase and plants need more water? In order to answer this question, we have focused on the differences in soil physical properties under four land management types (forest, pasture, traditional agriculture, and conservation agriculture) and whether these differences effect how water...
Unmanned Aircraft Systems
The USGS Ohio-Kentucky-Indiana Water Science Center has become a regional leader in using Unmanned Aircraft Systems (UAS), also known as drones, for mapping and hazards analysis.