William H Farmer
Science and Products
Water Budget Estimation and Evaluation Project
A comprehensive understanding of hydrologic processes that affect streamflow is required to effectively manage water resources to meet present and future human and environmental needs. The Water Budget Estimation and Evaluation Project (WBEEP) was created to a) estimate a complete water budget and deliver...
Trend Reproduction
As part of the National Water Budget Project, our objective is to quantify how well observed trends are simulated.
Water availability for ungauged rivers: an integrative, multi-model approach to estimate water availability at ungauged rivers across the United States
There has been increasing attention placed on the need for water availability information at ungauged locations, particularly related to balancing human and ecological needs for water. Critical to assessing water availability is the necessity for daily streamflow time series; however, most of the rivers in the United States are ungauged. This proposal leverages over $1M currently allocated to...
Quantifying uncertainty in simulated streamflow and runoff from a continental-scale monthly water balance model
One important component of continental-scale hydrologic modeling is quantifying the level of uncertainty in long-term hydrologic simulations and providing a range of possible simulated streamflow and/or runoff values for gaged and ungaged locations. In this paper, uncertainty was quantified for simulated streamflow and runoff generated from a...
Bock, Andrew R.; Farmer, William H.; Hay, Lauren E. Bias correction of simulated historical daily streamflow at ungauged locations by using independently estimated flow duration curves
In many simulations of historical daily streamflow distributional bias arising from the distributional properties of residuals has been noted. This bias often presents itself as an underestimation of high streamflow and an overestimation of low streamflow. Here, 1168 streamgages across the conterminous USA, having at least 14 ...
Farmer, William H.; Over, Thomas M.; Kiang, Julie E.
Continuing progress toward a national assessment of water availability and use
Executive SummaryThe Omnibus Public Land Management Act of 2009 (Public Law 111—11) was passed into law on March 30, 2009. Subtitle F, also known as the SECURE Water Act, calls for the establishment of a “national water availability and use assessment program” within the U.S. Geological Survey (USGS). The USGS issued the first report on the...
Evenson, Eric J.; Jones, Sonya A.; Barber, Nancy L.; Barlow, Paul M.; Blodgett, David L.; Bruce, Breton W.; Douglas-Mankin, Kyle; Farmer, William H.; Fischer, Jeffrey M.; Hughes, William B.; Kennen, Jonathan G.; Kiang, Julie E.; Maupin, Molly A.; Reeves, Howard W.; Senay, Gabriel B.; Stanton, Jennifer S.; Wagner, Chad R.; Wilson, Jennifer T.
Refinement of a regression-based method for prediction of flow-duration curves of daily streamflow in the conterminous United States
Regional regression is a common tool used to estimate daily flow-duration curves (FDCs) at ungaged locations. In this report, several refinements to a particular implementation of the regional regression method for estimating FDCs are evaluated by consideration of different methodological options through a leave-one-out cross-validation procedure...
Over, Thomas M.; Farmer, William H.; Russell, Amy M. Improving predictions of hydrological low-flow indices in ungaged basins using machine learning
We compare the ability of eight machine-learning models (elastic net, gradient boosting, kernel-k-nearest neighbors, two variants of support vector machines, M5-cubist, random forest, and a meta-learning ensemble M5-cubist model) and four baseline models (ordinary kriging, a unit area discharge model, and two variants of censored regression)...
Worland, Scott C.; Farmer, William H.; Kiang, Julie E. Geospatial tools effectively estimate nonexceedance probabilities of daily streamflow at ungauged and intermittently gauged locations in Ohio
Study regionThe state of Ohio in the United States, a humid, continental climate.Study focusThe estimation of nonexceedance probabilities of daily streamflows as an alternative means of establishing the relative magnitudes of streamflows associated with hydrologic and water-quality observations.New hydrological insights for the regionSeveral...
Farmer, William H.; Koltun, Greg
Water-quality trends in the nation’s rivers and streams, 1972–2012—Data preparation, statistical methods, and trend results
Since passage of the Clean Water Act in 1972, Federal, State, and local governments have invested billions of dollars to reduce pollution entering rivers and streams. To understand the return on these investments and to effectively manage and protect the Nation’s water resources in the future, we need to know how and why water quality has been...
Oelsner, Gretchen P.; Sprague, Lori A.; Murphy, Jennifer C.; Zuellig, Robert E.; Johnson, Henry M.; Ryberg, Karen R.; Falcone, James A.; Stets, Edward G.; Vecchia, Aldo V.; Riskin, Melissa L.; De Cicco, Laura A.; Mills, Taylor J.; Farmer, William H. On the deterministic and stochastic use of hydrologic models
Environmental simulation models, such as precipitation-runoff watershed models, are increasingly used in a deterministic manner for environmental and water resources design, planning, and management. In operational hydrology, simulated responses are now routinely used to plan, design, and manage a very wide class of water resource systems. However...
Farmer, William H.; Vogel, Richard M. Ordinary kriging as a tool to estimate historical daily streamflow records
Efficient and responsible management of water resources relies on accurate streamflow records. However, many watersheds are ungaged, limiting the ability to assess and understand local hydrology. Several tools have been developed to alleviate this data scarcity, but few provide continuous daily streamflow records at individual streamgages within...
Farmer, William H. Regional flow duration curves: Geostatistical techniques versus multivariate regression
A period-of-record flow duration curve (FDC) represents the relationship between the magnitude and frequency of daily streamflows. Prediction of FDCs is of great importance for locations characterized by sparse or missing streamflow observations. We present a detailed comparison of two methods which are capable of predicting an FDC at ungauged...
Pugliese, Alessio; Farmer, William H.; Castellarin, Attilio; Archfield, Stacey A.; Vogel, Richard M. Accelerating advances in continental domain hydrologic modeling
In the past, hydrologic modeling of surface water resources has mainly focused on simulating the hydrologic cycle at local to regional catchment modeling domains. There now exists a level of maturity among the catchment, global water security, and land surface modeling communities such that these communities are converging toward continental...
Archfield, Stacey A.; Clark, Martyn; Arheimer, Berit; Hay, Lauren E.; McMillan, Hilary; Kiang, Julie E.; Seibert, Jan; Hakala, Kirsti; Bock, Andrew R.; Wagener, Thorsten; Farmer, William H.; Andreassian, Vazken; Attinger, Sabine; Viglione, Alberto; Knight, Rodney; Markstrom, Steven; Over, Thomas M.
Evaluation of statistical and rainfall-runoff models for predicting historical daily streamflow time series in the Des Moines and Iowa River watersheds
Daily records of streamflow are essential to understanding hydrologic systems and managing the interactions between human and natural systems. Many watersheds and locations lack streamgages to provide accurate and reliable records of daily streamflow. In such ungaged watersheds, statistical tools and rainfall-runoff models are used to estimate...
Farmer, William H.; Knight, Rodney R.; Eash, David A.; Kasey J. Hutchinson; Linhart, S. Mike; Christiansen, Daniel E.; Archfield, Stacey A.; Over, Thomas M.; Kiang, Julie E.