Timothy K Cowdery
Biography
Tim Cowdery has been a hydrogeologist with the U.S. Geological Survey in Minnesota since 1991. He graduated with a BA in Geology from Carleton College in Minnesota and with a MS in Hydrogeology from the University of Minnesota. During his time at the USGS, Tim has managed many groundwater investigation projects focusing on groundwater quality, groundwater/surface-water interaction, quantification of groundwater flows, and numerical groundwater modeling. Tim has extensive experience in collecting continuous groundwater hydrographs, including both instrumentation and data-acquisition and correction automation. His interests also include graphical presention of scientific ideas and graphical design.
Tim Cowdery is a hydrogeologist with the U.S. Geological Survey in Mounds View, Minnesota. He currently serves as a chief for several projects at the Water-Science Center in Minnesota. He earned a master's degree from the University of Minnesota in groundwater geology in 1997. His research interests include groundwater/surface-water interactions, numerical groundwater modeling, and groundwater recharge analysis, and glacial geology.
Tim joined the USGS in 1992 as the groundwater specialist for the Red River of the North National Water-Quality Assessment, conducting groundwater-quality research at many spatial scales in that basin. He has designed and executed to two groundwater modeling studies at local and regional scales in southwestern Minnesota and in the southern Twin Cities Metropolitan area. He has developed systems for automated groundwater data collection, telemetry, and processing and has used these data to estimate the spatial and temporal variability of groundwater recharge.
Since 2002, Tim has managed the Glacial Ridge Hydrologic Assessment, a groundwater/surface water interaction study that documents changes in the hydrology of a large area in northwestern Minnesota undergoing extensive wetland and prairie restorations. This project is documenting changes in hydrologic flows and quality resulting from the restorations. He continues to manage several other projects involving groundwater modeling, water-quality sampling, groundwater recharge, and continuous groundwater level measurement.
Publications
Cowdery, T.K. and Brigham, M.E., 2013, Mercury in wetlands at the Glacial Ridge National Wildlife Refuge, northwestern Minnesota, 2007-9, U.S. Geological Survey Scientific Investigations Report 2013–5068, 17 p. [Link]
McMahon, P. B.; Cowdery, T. K.; Chapelle, F. H.; Jurgens, B. C., 2009. Redox Conditions in Selected Principal Aquifers of the United States. U.S. Geological Survey Fact Sheet 2009-3041, 6 p. [Link]
Cowdery, Timothy K.; Lorenz, David L.; Arntson, Allan D., 2008. Hydrology Prior to Wetland and Prairie Restoration in and around the Glacial Ridge National Wildlife Refuge, Northwestern Minnesota, 2002-5. Geological Survey (U.S.) Scientific Investigations Report 2007-5200, vi, 68 p. [Link]
Cowdery, Timothy K., 2005. Hydrogeology and ground-water/surface water interactions in the Des Moines River valley, southwestern Minnesota, 1997-2001. Scientific Investigations Report 2005-5219, viii, 51 p. [Link]
Ruhl, J. F.; Cowdery, T. K., 2004. Regional ground-water-flow models of surficial sand and gravel aquifers along the Mississippi River between Brainerd and St. Cloud, central Minnesota. Scientific Investigations Report 2004-5087, 26 p. [Link]
Lorenz, D. L.; Goldstein, R. M.; Cowdery, T. K.; Stoner, J. D., 2003. Comparison of two methods for delineating land use near monitoring wells used for assessing quality of shallow ground water. Water-Resources Investigations Report 2003-4067, vi, 13 p. : ill. (some col.), maps ; 28 cm. [Link]
Puckett, Larry J., Cowdery, Timothy K., 2002. Transport and fate of nitrate in a glacial outwash aquifer in relation to ground water age, land use practices, and redox processes: Journal of Environmental Quality, 31 (3), p. 782-796, illus. incl. 6 tables. [Link]
Puckett, Larry J., Cowdery, Timothy K., McMahon, Peter B., Tornes, Lan H., Stoner, Jeffrey D., 2002. Using chemical, hydrologic, and age dating analysis to delineate redox processes and flow paths in the riparian zone of a glacial outwash aquifer-stream system: Water Resources Research, 38 (8), p. 20, illus. incl. 5 tables, sketch map. [Link]
Cowdery, Timothy K., 1999. Water resources of the Prairie Island Indian Reservation, Minnesota, 1994-97. U.S. Dept. of the Interior, U.S. Geological Survey ; Branch of Information Services [distributor], Water-Resources Investigations Report 99-4069, iv, 36 p. :ill., maps ;28 cm. +1 computer disk (3 1/2 in.)
Puckett, Larry J., Cowdery, Timothy K., Lorenz, David L., Stoner, Jeffrey D., 1999. Estimation of nitrate contamination of an agro-ecosystem outwash aquifer using a nitrogen mass-balance budget: Journal of Environmental Quality, 28 (6), p. 2015-2025, illus. incl. 5 tables, sketch maps. [Link]
Trotta, L. C.; Cowdery, T. K., 1998. Ground water resources of the Mille Lacs Lake area, east-central Minnesota. U.S. Geological Survey ; Branch of Information Services [distributor], Water-Resources Investigations Report 97-4116, iv, 29 p. :ill., maps ;28 cm.
Cowdery, T. K., 1998. Ground-water quality in the Red River of the North Basin, Minnesota and North Dakota, 1991-95. U.S. Dept. of the Interior, U.S. Geological Survey ; Branch of Information Services [distributor], Water-Resources Investigations Report 98-4175, vi, 15 p. :ill., map ;28 cm.
Stoner, Jeffrey D.; Lorenz, D. L.; Goldstein, R. M.; Brigham, M. E.; Cowdery, T. K. , 1998. Water quality in the Red River of the North Basin, Minnesota, North Dakota, and South Dakota, 1992-95. U.S. Geological Survey, Circular 1169, 33 p. [Link]
Stoner, J. D.; Cowdery, T. K.; Puckett, L. J., 1997. Ground-water age dating and other tools used to assess land-use effects on water quality. U.S. Geological Survey, Water-Resources Investigations Report 97-4150, 1 folded sheet (6 p.) :col. ill., col. maps ;28 cm. [PGS - 5 p.]
Cowdery, Timothy K., 1997. Shallow Ground-Water Quality Beneath Cropland in the Red River of the North Basin, Minnesota and North Dakota, 1993-95. U.S. Geological Survey Water-Resources Investigations Report 97-4001, vii, 52 p.
Cowdery, T. K., 1995. Similar agricultural areas, different ground-water quality, Red River of the North Basin, 1993-95. U.S. Geological Survey, Open-File Report 95-441, 4 p. :col. ill., col. maps ;28 cm.
Science and Products
Groundwater monitoring and research
Groundwater is an important water resource. The USGS collects information on the quality and quantity of groundwater and conducts advanced modeling of groundwater flow and groundwater/surface-water systems. The USGS also evaluates the effects of water-use, land-use, and climate change on groundwater, surface-water, and the ecosystems that rely on them.
Assessing Hydrologic Changes in the St. Louis River Basin from Past Land Uses
Resource managers can use assessments of past and future land use to make science-based decisions. This project characterizes how changes in land use can change groundwater and surface-water flows in the St. Louis River Basin, MN. The USGS is constructing a set of groundwater models to simulate groundwater/surface-water interactions and evaluate how water flows have changed.
Continuous Groundwater Monitoring Network - Minnesota
This project monitors groundwater level, groundwater temperature and precipitation at hourly intervals at a long-term network of sites throughout Minnesota. These data are collected from surficial and buried aquifers and can be used to estimate groundwater recharge and assist water-availability assessments. Data are corrected to manual measurements at least twice per year and are available...
Simulation of the regional groundwater-flow system in the St. Louis River basin, Minnesota
The St. Louis River Basin (SLRB) covers 3,600 square miles in northeastern Minnesota, with headwaters in the Mesabi Range and extensive wetlands and lakes throughout the basin. To better understand the regional groundwater system in the SLRB, a two-dimensional, steady-state groundwater-flow model of the SLRB was developed by the U.S. Geological...
Haserodt, Megan J.; Hunt, Randall J.; Cowdery, Timothy K.; Leaf, Andrew T.; Baker, Anna C.
Redox Conditions in Selected Principal Aquifers of the United States
Reduction/oxidation (redox) processes affect the quality of groundwater in all aquifer systems. Redox processes can alternately mobilize or immobilize potentially toxic metals associated with naturally occurring aquifer materials, contribute to the degradation or preservation of anthropogenic contami-nants, and generate undesirable byproducts,...
McMahon, P.B.; Cowdery, T.K.; Chapelle, F.H.; Jurgens, B.C.
Hydrology Prior to Wetland and Prairie Restoration in and around the Glacial Ridge National Wildlife Refuge, Northwestern Minnesota, 2002-5
The Nature Conservancy (TNC) owned and managed 24,795 acres of mixed wetland, native prairie, farmland and woods east of Crookston, in northwestern Minnesota. The original wetlands and prairies that once occupied this land are being restored by TNC in cooperation with many partners and are becoming part of the Glacial Ridge National Wildlife...
Cowdery, Timothy K.; Lorenz, David L.; Arntson, Allan D. Hydrogeology and ground-water/surface water interactions in the Des Moines River valley, southwestern Minnesota, 1997-2001
Increased water demand in and around Windom led the U.S. Geological Survey, in cooperation with the Minnesota Department of Natural Resources, local water suppliers, and Cottonwood County, to study the hydrology of aquifers in the Des Moines River Valley near Windom. The study area is the watershed of a 30-kilometer (19-mile) reach of the Des...
Cowdery, Timothy K.
Regional ground-water-flow models of surficial sand and gravel aquifers along the Mississippi River between Brainerd and St. Cloud, central Minnesota
This report documents regional ground-waterflow models constructed by the U.S. Geological Survey in cooperation with the Minnesota Department of Health (MDH) to satisfy the requirements of their Source Water Protection Plan (SWPP). Steady-state single-layer ground-water-flow models were constructed with the computer program MODFLOW to simulate...
Ruhl, J.F.; Cowdery, T.K.
Comparison of two methods for delineating land use near monitoring wells used for assessing quality of shallow ground water
Two methods were compared for delineating land use near shallow monitoring wells. These wells were used to assess the effects of agricultural cropland on the quality of recently recharged ground water in two sand and gravel aquifers located near land surface. The two methods for delineating land use near wells were (1) the sector method, which...
Lorenz, D.L.; Goldstein, R.M.; Cowdery, T.K.; Stoner, J.D.
Water resources of the Prairie Island Indian Reservation, Minnesota, 1994-97
This evaluation of the water resources on the Prairie Island Indian Reservation includes data collected from 8 surface-water sites and 22 wells during 1994–97 and historical data. The Mississippi River and the lakes and wetlands connected to it are separated from the Vermillion River and the lakes and wetlands connected to it by the...
Cowdery, Timothy K.
Ground-water quality in the Red River of the North Basin, Minnesota and North Dakota, 1991-95
Surveys of water quality in surficial, buried glacial, and Cretaceous aquifers in the Red River of the North Basin during 1991-95 showed that some major-ion, nutrient, pesticide, and radioactive-element concentrations differed by physiographic area and differed among these aquifer types. Waters in surficial aquifers in the Drift Prairie (west) and...
Cowdery, T.K.
Water quality in the Red River of the North Basin, Minnesota, North Dakota, and South Dakota, 1992-95
This report is intended to summarize major findings that emerged between 1992 and 1995 from the water-quality assessment of the River River of the North basin study unit and to relate these findings to water-quality issues of regional and national concern. The information in primarily intended for those who are involved in water-resource...
Stoner, Jeffrey D.; Lorenz, D.L.; Goldstein, R.M.; Brigham, M.E.; Cowdery, T.K.
Ground water resources of the Mille Lacs Lake area, east-central Minnesota
The Mille Lacs Lake study area is a 960 mi2 area containing the ground-water and surface-water drainages to both Mille Lacs Lake and the first 12 miles of the Rum River. Within this study area, available ground water occurs in saturated, overlapping, discontinuous, partially-connected, glacially-deposited (hereinafter, glacial) aquifers and in...
Trotta, L.C.; Cowdery, T.K.
Ground-water age dating and other tools used to assess land-use effects on water quality
A relatively new method for age dating recent ground water along with other investigative tools improve our understanding of land-use effects on the water quality in a surficial aquifer and adjacent streams in the Red River of the North Basin: Ground water commonly takes more than 20 years to reach depths in the surficial aquifer where it is...
Stoner, J.D.; Cowdery, T.K.; Puckett, L.J.
Shallow ground-water quality beneath cropland in the Red River of the North Basin, Minnesota and North Dakota, 1993-95
During 1993-95, the agriculture on two sandy, surficial aquifers in the Red River of the North Basin affected the quality of shallow ground water in each aquifer differently. The Sheyenne Delta aquifer, in the western part of the basin, had land-use, hydrogeological, and rainfall characteristics that allowed few agricultural chemicals to reach or...
Cowdery, Timothy K.