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
Linkage of the Soil and Water Assessment Tool and the Texas Water Availability Model to simulate the effects of brush management on monthly storage of Canyon Lake, south-central Texas, 1995-2010 Linkage of the Soil and Water Assessment Tool and the Texas Water Availability Model to simulate the effects of brush management on monthly storage of Canyon Lake, south-central Texas, 1995-2010
The U.S. Geological Survey (USGS), in cooperation with the Texas State Soil and Water Conservation Board, developed and applied an approach to create a linkage between the published upper Guadalupe River Soil Water Assessment Tool (SWAT) brush-management (ashe juniper [Juniperus ashei]) model and the full authorization version Guadalupe River Water Availability Model (WAM). The SWAT...
Authors
William H. Asquith, Johnathan R. Bumgarner
Regression models of discharge and mean velocity associated with near-median streamflow conditions in Texas: utility of the U.S. Geological Survey discharge measurement database Regression models of discharge and mean velocity associated with near-median streamflow conditions in Texas: utility of the U.S. Geological Survey discharge measurement database
A database containing more than 16,300 discharge values and ancillary hydraulic attributes was assembled from summaries of discharge measurement records for 391 USGS streamflow-gauging stations (streamgauges) in Texas. Each discharge is between the 40th- and 60th-percentile daily mean streamflow as determined by period-of-record, streamgauge-specific, flow-duration curves. Each discharge...
Authors
William H. Asquith
Parameter estimation for the 4-parameter Asymmetric Exponential Power distribution by the method of L-moments using R Parameter estimation for the 4-parameter Asymmetric Exponential Power distribution by the method of L-moments using R
The implementation characteristics of two method of L-moments (MLM) algorithms for parameter estimation of the 4-parameter Asymmetric Exponential Power (AEP4) distribution are studied using the R environment for statistical computing. The objective is to validate the algorithms for general application of the AEP4 using R. An algorithm was introduced in the original study of the L-moments...
Authors
William H. Asquith
Return period adjustment for runoff coefficients based on analysis in undeveloped Texas watersheds Return period adjustment for runoff coefficients based on analysis in undeveloped Texas watersheds
The rational method for peak discharge (Qp) estimation was introduced in the 1880s. The runoff coefficient (C) is a key parameter for the rational method that has an implicit meaning of rate proportionality, and the C has been declared a function of the annual return period by various researchers. Rate-based runoff coefficients as a function of the return period, C(T), were determined...
Authors
Nirajan Dhakal, Xing Fang, William H. Asquith, Theodore G. Cleveland, David B. Thompson
Empirical flow parameters : a tool for hydraulic model validity Empirical flow parameters : a tool for hydraulic model validity
The objectives of this project were (1) To determine and present from existing data in Texas, relations between observed stream flow, topographic slope, mean section velocity, and other hydraulic factors, to produce charts such as Figure 1 and to produce empirical distributions of the various flow parameters to provide a methodology to "check if model results are way off!"; (2) To...
Authors
William H. Asquith, Thomas E. Burley, Theodore G. Cleveland
Generalized additive regression models of discharge and mean velocity associated with direct-runoff conditions in Texas: Utility of the U.S. Geological Survey discharge measurement database Generalized additive regression models of discharge and mean velocity associated with direct-runoff conditions in Texas: Utility of the U.S. Geological Survey discharge measurement database
A database containing more than 17,700 discharge values and ancillary hydraulic properties was assembled from summaries of discharge measurement records for 424 U.S. Geological Survey streamflow-gauging stations (stream gauges) in Texas. Each discharge exceeds the 90th-percentile daily mean streamflow as determined by period-of-record, stream-gauge-specific, flow-duration curves. Each...
Authors
William H. Asquith, George R. Herrmann, Theodore G. Cleveland
Filter Total Items: 48
RESTORE/makESTUSAL, Source code for construction of various statistical models and prediction of daily salinity in coastal regions of the Gulf of Mexico, United States RESTORE/makESTUSAL, Source code for construction of various statistical models and prediction of daily salinity in coastal regions of the Gulf of Mexico, United States
The RESTORE/makESTUSAL software repository contains R language source code that can be used for the construction of various statistical models and output time series of predicted daily salinity coastal regions of the Gulf of Mexico, United States. The source code is expansive, and the repository is organizationally deep following logical organization units. One major subsystem of the...
Simulation and comparison of five estimators of variability in units of standard deviation for small samples drawn from normally distributed data Simulation and comparison of five estimators of variability in units of standard deviation for small samples drawn from normally distributed data
It is convenient to measure or estimate variation in samples or distributions in units of standard deviations. There are alternative methods of estimation of standard deviation aside from the conventional and well-known definition. Estimation of standard deviation for very small samples (as small as two), whereas not always ideal, might be useful in certain practical circumstances. A...
Study of L-kurtosis and several distribution families for prediction of uncertainty distributions, An applied software technical note concerning L-kurtosis use in daily salinity prediction from multiple machine learning methods Study of L-kurtosis and several distribution families for prediction of uncertainty distributions, An applied software technical note concerning L-kurtosis use in daily salinity prediction from multiple machine learning methods
Statistical predictions that are based on multiple machine learning (MML) methods (from including differing training regimes) produce differing predictions. When the predictions are combined to a final estimate, then there are residuals of the predictions spread around the final estimate. It is common to assume normality or near-normality of the residuals (errors), but the assumption of...
RESTORE/covESTUSAL, Source code for construction of covariates bound to daily salinity and specific conductance data for purposes of statistical modeling in coastal regions of the Gulf of Mexico, United States RESTORE/covESTUSAL, Source code for construction of covariates bound to daily salinity and specific conductance data for purposes of statistical modeling in coastal regions of the Gulf of Mexico, United States
The RESTORE/covESTUSAL software repository contains R language source code useful for the construction of input tables of daily salinity and specific conductance (response variables) from multi-agency monitoring stations and potential predictor variables (covariates) intended for reuse in statistical model construction in coastal regions of the Gulf of Mexico, United States. The source...
Datasets of depth to water, spring 2016, 2018, and 2020, and spring-to-spring water-level change 2016-18, 2018-20, and 2016-20, Mississippi River Valley alluvial aquifer Datasets of depth to water, spring 2016, 2018, and 2020, and spring-to-spring water-level change 2016-18, 2018-20, and 2016-20, Mississippi River Valley alluvial aquifer
This data release consists of 4 data sets--rasters of generalized depth to water in the Mississippi River Valley alluvial aquifer (MRVA) in spring 2016, 2018, and 2020 and a point file of the wells with water-level measurements used to create the depth to water rasters and, for each well with applicable data, the values of water-level change from spring 2016 to spring 2018, spring 2018...
Quality Assurance of Water-Level Records from Wells in the Chicot aquifer system in southwestern Louisiana Department of Natural Resources' Stategic Online Natural Resources Information System (SONRIS) Quality Assurance of Water-Level Records from Wells in the Chicot aquifer system in southwestern Louisiana Department of Natural Resources' Stategic Online Natural Resources Information System (SONRIS)
The Louisiana Department of Natural Resources’ (LaDNR) Strategic Online Natural Resources Information System (SONRIS) is a repository for recent (1930–present) well information that includes date of completion, well construction, geology, and water level. Well information is provided by the well drillers during the permitting process and is updated regularly by LaDNR. This data set...
Filter Total Items: 22
utc2nwislocal, UTC date-times to NWIS local time zones using UTC offsets utc2nwislocal, UTC date-times to NWIS local time zones using UTC offsets
The utc2nwislocal package in the R language provides a light-weight, dependency-free utility for converting Coordinated Universal Time (UTC) base::as.POSIXct() date-time values into character-string representations for time zones. The UTC offsets for individual time zones are determined from the time-zone codes recognized by the U.S. Geological Survey National Water Information System...
infoGW2visGWDB, Conversion of an infoGW object to a GWmaster object compatible with the visGWDB software infoGW2visGWDB, Conversion of an infoGW object to a GWmaster object compatible with the visGWDB software
An R groundwater-data processing utility for manipulating, veracity checking, and converting an 'infoGW' object to the 'GWmaster' object for the visGWDB software with demonstration for the Mississippi River Valley alluvial aquifer
MGBT, Multiple Grubbs-Beck low-outlier test MGBT, Multiple Grubbs-Beck low-outlier test
The multiple Grubbs-Beck low-outlier test on positively distributed data is supported along, and utilities provided for noninterpretive U.S. Geological Survey (USGS) annual peak-streamflow data processing.
Source code in R to quality assure, plot, summarize, interpolate, and extend groundwater-level information, visGWDB---Groundwater-level informatics with demonstration for the Mississippi River Valley alluvial aquifer Source code in R to quality assure, plot, summarize, interpolate, and extend groundwater-level information, visGWDB---Groundwater-level informatics with demonstration for the Mississippi River Valley alluvial aquifer
This page contains extensive source code in the R language supporting groundwater level informatics, and the entry point is the script visGWDB.R. The approximately 4,000 lines of aggregate code requires also extensive external dependencies. The code provides for near arbitrary-scale information processing of observations or recordings of water levels associated groundwater resources. The...
Science and Products
Filter Total Items: 70
Linkage of the Soil and Water Assessment Tool and the Texas Water Availability Model to simulate the effects of brush management on monthly storage of Canyon Lake, south-central Texas, 1995-2010 Linkage of the Soil and Water Assessment Tool and the Texas Water Availability Model to simulate the effects of brush management on monthly storage of Canyon Lake, south-central Texas, 1995-2010
The U.S. Geological Survey (USGS), in cooperation with the Texas State Soil and Water Conservation Board, developed and applied an approach to create a linkage between the published upper Guadalupe River Soil Water Assessment Tool (SWAT) brush-management (ashe juniper [Juniperus ashei]) model and the full authorization version Guadalupe River Water Availability Model (WAM). The SWAT...
Authors
William H. Asquith, Johnathan R. Bumgarner
Regression models of discharge and mean velocity associated with near-median streamflow conditions in Texas: utility of the U.S. Geological Survey discharge measurement database Regression models of discharge and mean velocity associated with near-median streamflow conditions in Texas: utility of the U.S. Geological Survey discharge measurement database
A database containing more than 16,300 discharge values and ancillary hydraulic attributes was assembled from summaries of discharge measurement records for 391 USGS streamflow-gauging stations (streamgauges) in Texas. Each discharge is between the 40th- and 60th-percentile daily mean streamflow as determined by period-of-record, streamgauge-specific, flow-duration curves. Each discharge...
Authors
William H. Asquith
Parameter estimation for the 4-parameter Asymmetric Exponential Power distribution by the method of L-moments using R Parameter estimation for the 4-parameter Asymmetric Exponential Power distribution by the method of L-moments using R
The implementation characteristics of two method of L-moments (MLM) algorithms for parameter estimation of the 4-parameter Asymmetric Exponential Power (AEP4) distribution are studied using the R environment for statistical computing. The objective is to validate the algorithms for general application of the AEP4 using R. An algorithm was introduced in the original study of the L-moments...
Authors
William H. Asquith
Return period adjustment for runoff coefficients based on analysis in undeveloped Texas watersheds Return period adjustment for runoff coefficients based on analysis in undeveloped Texas watersheds
The rational method for peak discharge (Qp) estimation was introduced in the 1880s. The runoff coefficient (C) is a key parameter for the rational method that has an implicit meaning of rate proportionality, and the C has been declared a function of the annual return period by various researchers. Rate-based runoff coefficients as a function of the return period, C(T), were determined...
Authors
Nirajan Dhakal, Xing Fang, William H. Asquith, Theodore G. Cleveland, David B. Thompson
Empirical flow parameters : a tool for hydraulic model validity Empirical flow parameters : a tool for hydraulic model validity
The objectives of this project were (1) To determine and present from existing data in Texas, relations between observed stream flow, topographic slope, mean section velocity, and other hydraulic factors, to produce charts such as Figure 1 and to produce empirical distributions of the various flow parameters to provide a methodology to "check if model results are way off!"; (2) To...
Authors
William H. Asquith, Thomas E. Burley, Theodore G. Cleveland
Generalized additive regression models of discharge and mean velocity associated with direct-runoff conditions in Texas: Utility of the U.S. Geological Survey discharge measurement database Generalized additive regression models of discharge and mean velocity associated with direct-runoff conditions in Texas: Utility of the U.S. Geological Survey discharge measurement database
A database containing more than 17,700 discharge values and ancillary hydraulic properties was assembled from summaries of discharge measurement records for 424 U.S. Geological Survey streamflow-gauging stations (stream gauges) in Texas. Each discharge exceeds the 90th-percentile daily mean streamflow as determined by period-of-record, stream-gauge-specific, flow-duration curves. Each...
Authors
William H. Asquith, George R. Herrmann, Theodore G. Cleveland
Filter Total Items: 48
RESTORE/makESTUSAL, Source code for construction of various statistical models and prediction of daily salinity in coastal regions of the Gulf of Mexico, United States RESTORE/makESTUSAL, Source code for construction of various statistical models and prediction of daily salinity in coastal regions of the Gulf of Mexico, United States
The RESTORE/makESTUSAL software repository contains R language source code that can be used for the construction of various statistical models and output time series of predicted daily salinity coastal regions of the Gulf of Mexico, United States. The source code is expansive, and the repository is organizationally deep following logical organization units. One major subsystem of the...
Simulation and comparison of five estimators of variability in units of standard deviation for small samples drawn from normally distributed data Simulation and comparison of five estimators of variability in units of standard deviation for small samples drawn from normally distributed data
It is convenient to measure or estimate variation in samples or distributions in units of standard deviations. There are alternative methods of estimation of standard deviation aside from the conventional and well-known definition. Estimation of standard deviation for very small samples (as small as two), whereas not always ideal, might be useful in certain practical circumstances. A...
Study of L-kurtosis and several distribution families for prediction of uncertainty distributions, An applied software technical note concerning L-kurtosis use in daily salinity prediction from multiple machine learning methods Study of L-kurtosis and several distribution families for prediction of uncertainty distributions, An applied software technical note concerning L-kurtosis use in daily salinity prediction from multiple machine learning methods
Statistical predictions that are based on multiple machine learning (MML) methods (from including differing training regimes) produce differing predictions. When the predictions are combined to a final estimate, then there are residuals of the predictions spread around the final estimate. It is common to assume normality or near-normality of the residuals (errors), but the assumption of...
RESTORE/covESTUSAL, Source code for construction of covariates bound to daily salinity and specific conductance data for purposes of statistical modeling in coastal regions of the Gulf of Mexico, United States RESTORE/covESTUSAL, Source code for construction of covariates bound to daily salinity and specific conductance data for purposes of statistical modeling in coastal regions of the Gulf of Mexico, United States
The RESTORE/covESTUSAL software repository contains R language source code useful for the construction of input tables of daily salinity and specific conductance (response variables) from multi-agency monitoring stations and potential predictor variables (covariates) intended for reuse in statistical model construction in coastal regions of the Gulf of Mexico, United States. The source...
Datasets of depth to water, spring 2016, 2018, and 2020, and spring-to-spring water-level change 2016-18, 2018-20, and 2016-20, Mississippi River Valley alluvial aquifer Datasets of depth to water, spring 2016, 2018, and 2020, and spring-to-spring water-level change 2016-18, 2018-20, and 2016-20, Mississippi River Valley alluvial aquifer
This data release consists of 4 data sets--rasters of generalized depth to water in the Mississippi River Valley alluvial aquifer (MRVA) in spring 2016, 2018, and 2020 and a point file of the wells with water-level measurements used to create the depth to water rasters and, for each well with applicable data, the values of water-level change from spring 2016 to spring 2018, spring 2018...
Quality Assurance of Water-Level Records from Wells in the Chicot aquifer system in southwestern Louisiana Department of Natural Resources' Stategic Online Natural Resources Information System (SONRIS) Quality Assurance of Water-Level Records from Wells in the Chicot aquifer system in southwestern Louisiana Department of Natural Resources' Stategic Online Natural Resources Information System (SONRIS)
The Louisiana Department of Natural Resources’ (LaDNR) Strategic Online Natural Resources Information System (SONRIS) is a repository for recent (1930–present) well information that includes date of completion, well construction, geology, and water level. Well information is provided by the well drillers during the permitting process and is updated regularly by LaDNR. This data set...
Filter Total Items: 22
utc2nwislocal, UTC date-times to NWIS local time zones using UTC offsets utc2nwislocal, UTC date-times to NWIS local time zones using UTC offsets
The utc2nwislocal package in the R language provides a light-weight, dependency-free utility for converting Coordinated Universal Time (UTC) base::as.POSIXct() date-time values into character-string representations for time zones. The UTC offsets for individual time zones are determined from the time-zone codes recognized by the U.S. Geological Survey National Water Information System...
infoGW2visGWDB, Conversion of an infoGW object to a GWmaster object compatible with the visGWDB software infoGW2visGWDB, Conversion of an infoGW object to a GWmaster object compatible with the visGWDB software
An R groundwater-data processing utility for manipulating, veracity checking, and converting an 'infoGW' object to the 'GWmaster' object for the visGWDB software with demonstration for the Mississippi River Valley alluvial aquifer
MGBT, Multiple Grubbs-Beck low-outlier test MGBT, Multiple Grubbs-Beck low-outlier test
The multiple Grubbs-Beck low-outlier test on positively distributed data is supported along, and utilities provided for noninterpretive U.S. Geological Survey (USGS) annual peak-streamflow data processing.
Source code in R to quality assure, plot, summarize, interpolate, and extend groundwater-level information, visGWDB---Groundwater-level informatics with demonstration for the Mississippi River Valley alluvial aquifer Source code in R to quality assure, plot, summarize, interpolate, and extend groundwater-level information, visGWDB---Groundwater-level informatics with demonstration for the Mississippi River Valley alluvial aquifer
This page contains extensive source code in the R language supporting groundwater level informatics, and the entry point is the script visGWDB.R. The approximately 4,000 lines of aggregate code requires also extensive external dependencies. The code provides for near arbitrary-scale information processing of observations or recordings of water levels associated groundwater resources. 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