William H. Asquith
William has about 34 years at the USGS encompassing a wide range of algorithms and statistical and extreme value frequency studies of meteorology, surface water hydrology, and other water resources topics such as data acquisition, hydraulics, hydrologic regionalization, and research mentoring on statistical methods and algorithms.
Recent (2016–2026) research includes copula methods and algorithms; exceptionally low annual exceedance probability (AEP) flood events; regulated flood-frequency approaches; N-day volumetric flood frequency bias correction for all of US and Territories; statistics of USGS discharge measurements; technical advising on probable maximum precipitation in Texas and New Mexico-Colorado; flood- and rainfall-hazards for the Qashqadaryo Region, Uzbekistan, including defining an equal-area grid for Central Asian studies; small watershed hydrometeorological station operation; missing-record estimation; real-time uncertainty forecasting for hydrometeorological stations, and groundwater level informatics and machine-learning applications for prediction of monthly water-level grids for the Mississippi River Valley alluvial aquifer underlying the Mississippi River Alluvial Plain and Chicot aquifer, southwestern Louisiana; long-term trend analyses of daily salinity predictions for 91 monitoring locations in bays and estuaries of the gulf coast with statistical methods including Cubist, Randomforest, and Support Vector Machines; Texas lake-evaporation validation by probabilistic methods (linear moments); and reduction in USGS staffing efforts in groundwater monitoring with minimization of loss of information content from the Louisiana network.
Recent cooperators include Gulf Coast Ecosystem Restoration Council, Environment Agency – Abu Dhabi (2016−18) and Ministry of Ecology, Environmental Protection and Climate Change for the Republic of Uzbekistan (2021−26) via USGS Office of International Programs, Texas Commission on Environmental Quality, Texas Department of Transportation, Texas Water Development Board, U.S. Army Corps of Engineers, U.S. Nuclear Regulatory Commission, and USGS Office of Quality Assurance.
Thrice featured four-city speaker in 2016, 2017, and 2018 in Bolivia for Universidad Catolica Boliviana and U.S. State Department, and USGS Surfacewater Mission co-lead to Uzbekistan (June 2022, April 2024, September 2024).
Education and Certifications
Institution: Texas Tech University (TTU), College of Engineering, Lubbock, 2008–2011
Degree: Ph.D. (Civil Engineering, May 2011)Institution: University of Texas at Austin, Jackson School of Geosciences, Geoscience, 1998–2003
Degree: Ph.D. (Geosciences, May 2003)Institution: University of Texas at Austin, College of Engineering, 1988–1994
Degrees: B.S. (Civil Engineering, Dec. 1992); M.S. (Civil Engineering, May 1994)
Affiliations and Memberships*
Professional Geoscientist no. 1494, State of Texas 2003–present
Science and Products
Filter Total Items: 70
Annual and approximately quarterly series peak streamflow derived from interpretations of indirect measurements for a crest-stage gage network in Texas through water year 2015 Annual and approximately quarterly series peak streamflow derived from interpretations of indirect measurements for a crest-stage gage network in Texas through water year 2015
In 2006, the U.S. Geological Survey (USGS), in cooperation with the Texas Department of Transportation, began collecting annual and approximately quarterly series peak-streamflow data at streamflow-gaging stations in smallto medium-sized watersheds in central and western Texas as part of a crest-stage gage (CSG) network, along with selected flood-hydrograph data at a subset of these...
Authors
William H. Asquith, Glenn R. Harwell, Karl E. Winters
Application of at-site peak-streamflow frequency analyses for very low annual exceedance probabilities Application of at-site peak-streamflow frequency analyses for very low annual exceedance probabilities
The U.S. Geological Survey (USGS), in cooperation with the U.S. Nuclear Regulatory Commission, has investigated statistical methods for probabilistic flood hazard assessment to provide guidance on very low annual exceedance probability (AEP) estimation of peak-streamflow frequency and the quantification of corresponding uncertainties using streamgage-specific data. The term “very low AEP...
Authors
William H. Asquith, Julie E. Kiang, Timothy A. Cohn
Refining previous estimates of groundwater outflows from the Medina/Diversion Lake system, San Antonio area, Texas Refining previous estimates of groundwater outflows from the Medina/Diversion Lake system, San Antonio area, Texas
Introduction In 2016, the U.S. Geological Survey (USGS), in cooperation with the San Antonio Water System, began a study to refine previously derived estimates of groundwater outflows from Medina and Diversion Lakes in south-central Texas near San Antonio. When full, Medina and Diversion Lakes (hereinafter referred to as the Medina/Diversion Lake system) (fig. 1) impound approximately...
Authors
Richard N. Slattery, William H. Asquith, John D. Gordon
Long-term trends in reservoir water quality and quantity in two major river basins of the southern Great Plains Long-term trends in reservoir water quality and quantity in two major river basins of the southern Great Plains
Trends in water quality and quantity were assessed for 11 major reservoirs of the Brazos and Colorado river basins in the southern Great Plains (maximum period of record, 1965–2010). Water quality, major contributing-stream inflow, storage, local precipitation, and basin-wide total water withdrawals were analyzed. Inflow and storage decreased and total phosphorus increased in most...
Authors
D. Dawson, Matthew M. VanLandeghem, William H. Asquith, Reynaldo Patino
Lithologic and hydrologic controls of mixed alluvial-bedrock channels in flood-prone fluvial systems: bankfull and macrochannels in the Llano River watershed, central Texas, USA Lithologic and hydrologic controls of mixed alluvial-bedrock channels in flood-prone fluvial systems: bankfull and macrochannels in the Llano River watershed, central Texas, USA
The rural and unregulated Llano River watershed located in central Texas, USA, has a highly variable flow regime and a wide range of instantaneous peak flows. Abrupt transitions in surface lithology exist along the main-stem channel course. Both of these characteristics afford an opportunity to examine hydrologic, lithologic, and sedimentary controls on downstream changes in channel...
Authors
Frank T. Heitmuller, Paul F. Hudson, William H. Asquith
Trend analysis and selected summary statistics of annual mean streamflow for 38 selected long-term U.S. Geological Survey streamgages in Texas, water years 1916-2012 Trend analysis and selected summary statistics of annual mean streamflow for 38 selected long-term U.S. Geological Survey streamgages in Texas, water years 1916-2012
In 2013, the U.S. Geological Survey (USGS) operated more than 500 continuous streamgages (streamflow-gaging stations) in Texas. In cooperation with the Texas Water Development Board, the USGS evaluated mean annual streamflow data for 38 selected streamgages that were active as of water year 2012. The 38 streamgages have annual mean streamflow data considered natural and unregulated...
Authors
William H. Asquith, Dana L. Barbie
Filter Total Items: 48
Modeled daily salinity derived from multiple machine learning methodologies and generalized additive models for three salinity monitoring sites in Mobile Bay, northern Gulf of Mexico, 1980–2021 Modeled daily salinity derived from multiple machine learning methodologies and generalized additive models for three salinity monitoring sites in Mobile Bay, northern Gulf of Mexico, 1980–2021
Results from generalized additive models (GAM), random forest models (RFM), and cubist models (CUB) for three Dauphin Island Sealab (DIS) operated salinity sites in Mobile Bay are reported in this data release. These sites included Meaher Park (DIS:MHPA1), Middle Bay Lighthouse (DIS:MBLA1), and Dauphin Island (DIS:DPIA1). The constructed models predicted a 42-year daily salinity record...
infoGWauxs, Auxiliary methods for infoGW and similar groundwater level data objects and other helpful utilities infoGWauxs, Auxiliary methods for infoGW and similar groundwater level data objects and other helpful utilities
The infoGWauxs package in the R language provides auxiliary methods for data merging, duplicate-record removal, and monthly rollup of groundwater levels in the so-called infoGW or GWmaster data objects. These data structures are particularly well suited for statistical analyses of groundwater levels. This package is part of a greater body of data processors oriented around the infoGW...
Quality assurance of water levels in the Mississippi River Valley alluvial aquifer in Louisiana from the Louisiana Department of Natural Resources' Strategic Online Natural Resources Information System (SONRIS) Quality assurance of water levels in the Mississippi River Valley alluvial aquifer in Louisiana from the Louisiana Department of Natural Resources' Strategic Online Natural Resources Information System (SONRIS)
This data release provides several data files representing groundwater levels reported through driller's reports for the State of Louisiana Department of Natural Resources (Louisiana Department of Natural Resources, 2023) within or near the Mississippi Alluvial Plain (MAP) and (or) associated with the Mississippi River Valley alluvial aquifer (MRVA). First, a retrieval of data from the...
Quality assurance of water levels in the Mississippi River Valley alluvial aquifer in Arkansas from the Arkansas Department of Agriculture Natural Resources Division Quality assurance of water levels in the Mississippi River Valley alluvial aquifer in Arkansas from the Arkansas Department of Agriculture Natural Resources Division
This data release provides several data files representing groundwater levels reported through driller's reports for the State of Arkansas Arkansas Department of Agriculture National Resources Division (https://wise.er.usgs.gov/driller_db/) (accessed January 10, 2024) within or near the Mississippi Alluvial Plain (MAP) and (or) associated with the Mississippi River Valley alluvial...
Imputed daily salinity and associated covariates to support statistical modeling for 91 salinity monitoring sites in the northern Gulf of Mexico Imputed daily salinity and associated covariates to support statistical modeling for 91 salinity monitoring sites in the northern Gulf of Mexico
Imputed salinities from either salinity or specific conductance observations and covariate data in data structures deemed suitable for statistical modeling of salinity in near-coastal environments of the northern Gulf of Mexico are provided for 15 salinity groups. The data herein were created by the 'covardr2formodel.R' script of 'covESTUSAL software' (Asquith and others, 2023), which...
Geospatial representations of salinity monitoring site and bay and estuary group boundaries in the Gulf of Mexico Geospatial representations of salinity monitoring site and bay and estuary group boundaries in the Gulf of Mexico
The polygon datasets were created to assist in visualizing the results of salinity modeling in Gulf of Mexico estuaries and bays. Statistical algorithms (Asquith and others, 2023) were developed to predict daily salinities for 91 salinity monitoring sites (Rodgers and Swarzenski, 2019) operated by 7 agencies in near coastal United States waters of the Gulf of Mexico. These monitoring...
Filter Total Items: 22
aqtsra, Utilities for preprocessing raw and approved unit-value time-series hydrometeorological data before statistical endeavors aqtsra, Utilities for preprocessing raw and approved unit-value time-series hydrometeorological data before statistical endeavors
The aqtsra package in the R language provides a light-weight utility for merging U.S. Geological Survey National Water Information System (NWIS) flat-file tables of raw and approved unit-value time-series data from the AQUARIUS Time-Series software. Provision is made for parsing time stamps, insertion of the day fraction into the year, and days since last site visit among other limited...
covMRVAgen1, Source code for construction of covariates bound to monthly groundwater levels for purposes of statistical modeling of water levels in the Mississippi River Valley alluvial aquifer covMRVAgen1, Source code for construction of covariates bound to monthly groundwater levels for purposes of statistical modeling of water levels in the Mississippi River Valley alluvial aquifer
The covMRVAgen1 repository contains R (primarily), Mermaid, Perl, and Python language source code that can be used the construction of input tables of monthly groundwater levels (response variable) and predictor variables (covariates) for statistical modeling of water levels in the Mississippi River Valley alluvial aquifer within the Mississippi Alluvial Plain, south-central United...
scNIDaregis, Geospatial processing of dams in the United States from the National Inventory of Dams with a state-level aggregation scheme, demonstrated for selected dams in eight states in south-central region of the United States, and post-processing fea scNIDaregis, Geospatial processing of dams in the United States from the National Inventory of Dams with a state-level aggregation scheme, demonstrated for selected dams in eight states in south-central region of the United States, and post-processing fea
This repository contains R language source code used to read eight tab-delimited text files of state-level instances of the U.S. Army Corps of Engineers National Inventory of Dams (NID). The text file were generated from spreadsheets, which themselves are column-trimmed versions of spreadsheets that were downloaded from the public interface to the NID. The focus of the repository is on...
Source code in R for creation of regional regression equations for estimation of four hydraulic properties of streams at approximate bankfull conditions for different ecoregions in Texas associated with U.S. Geological Survey Scientific Investigations Rep Source code in R for creation of regional regression equations for estimation of four hydraulic properties of streams at approximate bankfull conditions for different ecoregions in Texas associated with U.S. Geological Survey Scientific Investigations Rep
This repository contains R language source code used for creation of regional regression equations for estimation of four hydraulic properties of streams at approximate bankfull conditions for different ecoregions in Texas. This code is in support of the following study: Asquith, W.H., Gordon, J.D., and Wallace, D.S., 2020, Regional regression equations for estimation of four hydraulic...
trajPipeFlow, Discharge from horizontal and vertical flowing pipes by trajectory methods trajPipeFlow, Discharge from horizontal and vertical flowing pipes by trajectory methods
The trajPipeFlow package in the R language provides functions for computation of discharge from horizontal and vertical flowing pipes using trajectory methods of the U.S. Bureau of Reclamation Water Measurement Manual (2001, chap. 14, sec. 13).
RESTORE/fdclmrpplo, Source code for estimation of L-moments and percent no-flow conditions for decadal flow-duration curves and estimation at level-12 hydrologic unit codes along with other statistical computations RESTORE/fdclmrpplo, Source code for estimation of L-moments and percent no-flow conditions for decadal flow-duration curves and estimation at level-12 hydrologic unit codes along with other statistical computations
The RESTORE/fdclmrpplo repository contains R language source code used for estimation of the L-moments and percent no-flow conditions (no-flow fractions) for decadal flow-duration curves and estimation at streamgages and level-12 hydrologic unit codes using generalized additive models and censored generalized additive models. The source code is designed to streamline the workflow for the...
Science and Products
Filter Total Items: 70
Annual and approximately quarterly series peak streamflow derived from interpretations of indirect measurements for a crest-stage gage network in Texas through water year 2015 Annual and approximately quarterly series peak streamflow derived from interpretations of indirect measurements for a crest-stage gage network in Texas through water year 2015
In 2006, the U.S. Geological Survey (USGS), in cooperation with the Texas Department of Transportation, began collecting annual and approximately quarterly series peak-streamflow data at streamflow-gaging stations in smallto medium-sized watersheds in central and western Texas as part of a crest-stage gage (CSG) network, along with selected flood-hydrograph data at a subset of these...
Authors
William H. Asquith, Glenn R. Harwell, Karl E. Winters
Application of at-site peak-streamflow frequency analyses for very low annual exceedance probabilities Application of at-site peak-streamflow frequency analyses for very low annual exceedance probabilities
The U.S. Geological Survey (USGS), in cooperation with the U.S. Nuclear Regulatory Commission, has investigated statistical methods for probabilistic flood hazard assessment to provide guidance on very low annual exceedance probability (AEP) estimation of peak-streamflow frequency and the quantification of corresponding uncertainties using streamgage-specific data. The term “very low AEP...
Authors
William H. Asquith, Julie E. Kiang, Timothy A. Cohn
Refining previous estimates of groundwater outflows from the Medina/Diversion Lake system, San Antonio area, Texas Refining previous estimates of groundwater outflows from the Medina/Diversion Lake system, San Antonio area, Texas
Introduction In 2016, the U.S. Geological Survey (USGS), in cooperation with the San Antonio Water System, began a study to refine previously derived estimates of groundwater outflows from Medina and Diversion Lakes in south-central Texas near San Antonio. When full, Medina and Diversion Lakes (hereinafter referred to as the Medina/Diversion Lake system) (fig. 1) impound approximately...
Authors
Richard N. Slattery, William H. Asquith, John D. Gordon
Long-term trends in reservoir water quality and quantity in two major river basins of the southern Great Plains Long-term trends in reservoir water quality and quantity in two major river basins of the southern Great Plains
Trends in water quality and quantity were assessed for 11 major reservoirs of the Brazos and Colorado river basins in the southern Great Plains (maximum period of record, 1965–2010). Water quality, major contributing-stream inflow, storage, local precipitation, and basin-wide total water withdrawals were analyzed. Inflow and storage decreased and total phosphorus increased in most...
Authors
D. Dawson, Matthew M. VanLandeghem, William H. Asquith, Reynaldo Patino
Lithologic and hydrologic controls of mixed alluvial-bedrock channels in flood-prone fluvial systems: bankfull and macrochannels in the Llano River watershed, central Texas, USA Lithologic and hydrologic controls of mixed alluvial-bedrock channels in flood-prone fluvial systems: bankfull and macrochannels in the Llano River watershed, central Texas, USA
The rural and unregulated Llano River watershed located in central Texas, USA, has a highly variable flow regime and a wide range of instantaneous peak flows. Abrupt transitions in surface lithology exist along the main-stem channel course. Both of these characteristics afford an opportunity to examine hydrologic, lithologic, and sedimentary controls on downstream changes in channel...
Authors
Frank T. Heitmuller, Paul F. Hudson, William H. Asquith
Trend analysis and selected summary statistics of annual mean streamflow for 38 selected long-term U.S. Geological Survey streamgages in Texas, water years 1916-2012 Trend analysis and selected summary statistics of annual mean streamflow for 38 selected long-term U.S. Geological Survey streamgages in Texas, water years 1916-2012
In 2013, the U.S. Geological Survey (USGS) operated more than 500 continuous streamgages (streamflow-gaging stations) in Texas. In cooperation with the Texas Water Development Board, the USGS evaluated mean annual streamflow data for 38 selected streamgages that were active as of water year 2012. The 38 streamgages have annual mean streamflow data considered natural and unregulated...
Authors
William H. Asquith, Dana L. Barbie
Filter Total Items: 48
Modeled daily salinity derived from multiple machine learning methodologies and generalized additive models for three salinity monitoring sites in Mobile Bay, northern Gulf of Mexico, 1980–2021 Modeled daily salinity derived from multiple machine learning methodologies and generalized additive models for three salinity monitoring sites in Mobile Bay, northern Gulf of Mexico, 1980–2021
Results from generalized additive models (GAM), random forest models (RFM), and cubist models (CUB) for three Dauphin Island Sealab (DIS) operated salinity sites in Mobile Bay are reported in this data release. These sites included Meaher Park (DIS:MHPA1), Middle Bay Lighthouse (DIS:MBLA1), and Dauphin Island (DIS:DPIA1). The constructed models predicted a 42-year daily salinity record...
infoGWauxs, Auxiliary methods for infoGW and similar groundwater level data objects and other helpful utilities infoGWauxs, Auxiliary methods for infoGW and similar groundwater level data objects and other helpful utilities
The infoGWauxs package in the R language provides auxiliary methods for data merging, duplicate-record removal, and monthly rollup of groundwater levels in the so-called infoGW or GWmaster data objects. These data structures are particularly well suited for statistical analyses of groundwater levels. This package is part of a greater body of data processors oriented around the infoGW...
Quality assurance of water levels in the Mississippi River Valley alluvial aquifer in Louisiana from the Louisiana Department of Natural Resources' Strategic Online Natural Resources Information System (SONRIS) Quality assurance of water levels in the Mississippi River Valley alluvial aquifer in Louisiana from the Louisiana Department of Natural Resources' Strategic Online Natural Resources Information System (SONRIS)
This data release provides several data files representing groundwater levels reported through driller's reports for the State of Louisiana Department of Natural Resources (Louisiana Department of Natural Resources, 2023) within or near the Mississippi Alluvial Plain (MAP) and (or) associated with the Mississippi River Valley alluvial aquifer (MRVA). First, a retrieval of data from the...
Quality assurance of water levels in the Mississippi River Valley alluvial aquifer in Arkansas from the Arkansas Department of Agriculture Natural Resources Division Quality assurance of water levels in the Mississippi River Valley alluvial aquifer in Arkansas from the Arkansas Department of Agriculture Natural Resources Division
This data release provides several data files representing groundwater levels reported through driller's reports for the State of Arkansas Arkansas Department of Agriculture National Resources Division (https://wise.er.usgs.gov/driller_db/) (accessed January 10, 2024) within or near the Mississippi Alluvial Plain (MAP) and (or) associated with the Mississippi River Valley alluvial...
Imputed daily salinity and associated covariates to support statistical modeling for 91 salinity monitoring sites in the northern Gulf of Mexico Imputed daily salinity and associated covariates to support statistical modeling for 91 salinity monitoring sites in the northern Gulf of Mexico
Imputed salinities from either salinity or specific conductance observations and covariate data in data structures deemed suitable for statistical modeling of salinity in near-coastal environments of the northern Gulf of Mexico are provided for 15 salinity groups. The data herein were created by the 'covardr2formodel.R' script of 'covESTUSAL software' (Asquith and others, 2023), which...
Geospatial representations of salinity monitoring site and bay and estuary group boundaries in the Gulf of Mexico Geospatial representations of salinity monitoring site and bay and estuary group boundaries in the Gulf of Mexico
The polygon datasets were created to assist in visualizing the results of salinity modeling in Gulf of Mexico estuaries and bays. Statistical algorithms (Asquith and others, 2023) were developed to predict daily salinities for 91 salinity monitoring sites (Rodgers and Swarzenski, 2019) operated by 7 agencies in near coastal United States waters of the Gulf of Mexico. These monitoring...
Filter Total Items: 22
aqtsra, Utilities for preprocessing raw and approved unit-value time-series hydrometeorological data before statistical endeavors aqtsra, Utilities for preprocessing raw and approved unit-value time-series hydrometeorological data before statistical endeavors
The aqtsra package in the R language provides a light-weight utility for merging U.S. Geological Survey National Water Information System (NWIS) flat-file tables of raw and approved unit-value time-series data from the AQUARIUS Time-Series software. Provision is made for parsing time stamps, insertion of the day fraction into the year, and days since last site visit among other limited...
covMRVAgen1, Source code for construction of covariates bound to monthly groundwater levels for purposes of statistical modeling of water levels in the Mississippi River Valley alluvial aquifer covMRVAgen1, Source code for construction of covariates bound to monthly groundwater levels for purposes of statistical modeling of water levels in the Mississippi River Valley alluvial aquifer
The covMRVAgen1 repository contains R (primarily), Mermaid, Perl, and Python language source code that can be used the construction of input tables of monthly groundwater levels (response variable) and predictor variables (covariates) for statistical modeling of water levels in the Mississippi River Valley alluvial aquifer within the Mississippi Alluvial Plain, south-central United...
scNIDaregis, Geospatial processing of dams in the United States from the National Inventory of Dams with a state-level aggregation scheme, demonstrated for selected dams in eight states in south-central region of the United States, and post-processing fea scNIDaregis, Geospatial processing of dams in the United States from the National Inventory of Dams with a state-level aggregation scheme, demonstrated for selected dams in eight states in south-central region of the United States, and post-processing fea
This repository contains R language source code used to read eight tab-delimited text files of state-level instances of the U.S. Army Corps of Engineers National Inventory of Dams (NID). The text file were generated from spreadsheets, which themselves are column-trimmed versions of spreadsheets that were downloaded from the public interface to the NID. The focus of the repository is on...
Source code in R for creation of regional regression equations for estimation of four hydraulic properties of streams at approximate bankfull conditions for different ecoregions in Texas associated with U.S. Geological Survey Scientific Investigations Rep Source code in R for creation of regional regression equations for estimation of four hydraulic properties of streams at approximate bankfull conditions for different ecoregions in Texas associated with U.S. Geological Survey Scientific Investigations Rep
This repository contains R language source code used for creation of regional regression equations for estimation of four hydraulic properties of streams at approximate bankfull conditions for different ecoregions in Texas. This code is in support of the following study: Asquith, W.H., Gordon, J.D., and Wallace, D.S., 2020, Regional regression equations for estimation of four hydraulic...
trajPipeFlow, Discharge from horizontal and vertical flowing pipes by trajectory methods trajPipeFlow, Discharge from horizontal and vertical flowing pipes by trajectory methods
The trajPipeFlow package in the R language provides functions for computation of discharge from horizontal and vertical flowing pipes using trajectory methods of the U.S. Bureau of Reclamation Water Measurement Manual (2001, chap. 14, sec. 13).
RESTORE/fdclmrpplo, Source code for estimation of L-moments and percent no-flow conditions for decadal flow-duration curves and estimation at level-12 hydrologic unit codes along with other statistical computations RESTORE/fdclmrpplo, Source code for estimation of L-moments and percent no-flow conditions for decadal flow-duration curves and estimation at level-12 hydrologic unit codes along with other statistical computations
The RESTORE/fdclmrpplo repository contains R language source code used for estimation of the L-moments and percent no-flow conditions (no-flow fractions) for decadal flow-duration curves and estimation at streamgages and level-12 hydrologic unit codes using generalized additive models and censored generalized additive models. The source code is designed to streamline the workflow for the...
*Disclaimer: Listing outside positions with professional scientific organizations on this Staff Profile are for informational purposes only and do not constitute an endorsement of those professional scientific organizations or their activities by the USGS, Department of the Interior, or U.S. Government