Geology topics

David B. Thompson

Publications and source records attributed to David B. Thompson.

8 recordsLinked to original sources

USGS2013

Return period adjustment for runoff coefficients based on analysis in undeveloped Texas watersheds

The rational method for peak discharge (Q p ) 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 for 36 undeveloped watersheds in Texas using peak discharge frequency from previously published regional regression equations and rainfall intensity frequency for return periods T of 2, 5, 10, 25, 50, and 100 years. The C(T) values and return period adjustments C(T)/C(T=10 year) determined in this study are most applicable to undeveloped watersheds. The return period adjustments determined for the Texas watersheds in this study and those extracted from prior studies of non-Texas data exceed values from well-known literature such as design manuals and textbooks. Most importantly, the return period adjustments exceed values currently recognized in Texas Department of Transportation design guidance when T>10 years.

Texas↗

USGS2011

Estimation of volumetric runoff coefficients for Texas watersheds using land-use and rainfall-runoff data

The rational method for peak discharge ( Q p "> Q p ) estimation was introduced in the 1880s. Although the rational method is considered simplistic, it remains an effective method for estimating peak discharge for small watersheds. The runoff coefficient ( C "> C ) is a key parameter for the rational method and can be estimated in various ways. Literature-based C "> C values ( C lit "> C lit ) are listed for different land-use/land cover (two words, no hyphen) (LULC) conditions in various design manuals and textbooks; however, these C lit "> C lit values were developed with little basis on observed rainfall and runoff data. In this paper, C lit "> C lit values were derived for 90 watersheds in Texas by using LULC data for 1992 and 2001; the C lit "> C lit values derived from the two data sets were essentially the same. Also for this study, volumetric runoff coefficients ( C v "> C v ) were estimated by using observed rainfall and runoff depths from more than 1,600 events observed in the watersheds. Watershed-median and watershed-average C v "> C v values were computed, and both are consistent with data from the National Urban Runoff Program. In addition, C v "> C v values were estimated by using rank-ordered pairs of rainfall and runoff depths (i.e., frequency matching). As anticipated, C "> C values derived by all three methods (literature based, event totals, and frequency matching) consistently had larger values for developed watersheds than for undeveloped watersheds. Two regression equations of C v "> C v versus percent impervious area were developed and combined into a single equation that can be used to rapidly estimate C v "> C v values for similar Texas watersheds.

Texas↗

USGS2008

Alternative Regression Equations for Estimation of Annual Peak-Streamflow Frequency for Undeveloped Watersheds in Texas using PRESS Minimization

The U.S. Geological Survey, in cooperation with the Texas Department of Transportation and in partnership with Texas Tech University, investigated a refinement of the regional regression method and developed alternative equations for estimation of peak-streamflow frequency for undeveloped watersheds in Texas. A common model for estimation of peak-streamflow frequency is based on the regional regression method. The current (2008) regional regression equations for 11 regions of Texas are based on log10 transformations of all regression variables (drainage area, main-channel slope, and watershed shape). Exclusive use of log10-transformation does not fully linearize the relations between the variables. As a result, some systematic bias remains in the current equations. The bias results in overestimation of peak streamflow for both the smallest and largest watersheds. The bias increases with increasing recurrence interval. The primary source of the bias is the discernible curvilinear relation in log10 space between peak streamflow and drainage area. Bias is demonstrated by selected residual plots with superimposed LOWESS trend lines. To address the bias, a statistical framework based on minimization of the PRESS statistic through power transformation of drainage area is described and implemented, and the resulting regression equations are reported. Compared to log10-exclusive equations, the equations derived from PRESS minimization have PRESS statistics and residual standard errors less than the log10 exclusive equations. Selected residual plots for the PRESS-minimized equations are presented to demonstrate that systematic bias in regional regression equations for peak-streamflow frequency estimation in Texas can be reduced. Because the overall error is similar to the error associated with previous equations and because the bias is reduced, the PRESS-minimized equations reported here provide alternative equations for peak-streamflow frequency estimation.

Scientific Investigations Report↗

USGS2006

Statistical characteristics of storm interevent time, depth, and duration for eastern New Mexico, Oklahoma, and Texas

The design of small runoff-control structures, from simple floodwater-detention basins to sophisticated best-management practices, requires the statistical characterization of rainfall as a basis for cost-effective, risk-mitigated, hydrologic engineering design. The U.S. Geological Survey, in cooperation with the Texas Department of Transportation, has developed a framework to estimate storm statistics including storm interevent times, distributions of storm depths, and distributions of storm durations for eastern New Mexico, Oklahoma, and Texas. The analysis is based on hourly rainfall recorded by the National Weather Service. The database contains more than 155 million hourly values from 774 stations in the study area. Seven sets of maps depicting ranges of mean storm interevent time, mean storm depth, and mean storm duration, by county, as well as tables listing each of those statistics, by county, were developed. The mean storm interevent time is used in probabilistic models to assess the frequency distribution of storms. The Poisson distribution is suggested to model the distribution of storm occurrence, and the exponential distribution is suggested to model the distribution of storm interevent times. The four-parameter kappa distribution is judged as an appropriate distribution for modeling the distribution of both storm depth and storm duration. Preference for the kappa distribution is based on interpretation of L-moment diagrams. Parameter estimates for the kappa distributions are provided. Separate dimensionless frequency curves for storm depth and duration are defined for eastern New Mexico, Oklahoma, and Texas. Dimension is restored by multiplying curve ordinates by the mean storm depth or mean storm duration to produce quantile functions of storm depth and duration. Minimum interevent time and location have slight influence on the scale and shape of the dimensionless frequency curves. Ten example problems and solutions to possible applications are provided.

New Mexico, Oklahoma, Texas↗

USGS2005

Literature review for Texas Department of Transportation Research Project 0-4695: Guidance for design in areas of extreme bed-load mobility, Edwards Plateau, Texas

A review of the literature addressing sediment transport in gravel-bed river systems and structures designed to control bed-load mobility is provided as part of Texas Department of Transportation research project 0–4695: Guidance for Design in Areas of Extreme Bed-Load Mobility. The study area comprises the western half of the Edwards Plateau in central Texas. Three primary foci of the literature review are journal articles, edited volumes, and government publications. Major themes within the body of literature include deterministic sediment transport theory and equations, development of methods to measure and analyze fluvial sediment, applications and development of theory in natural channels and flume experiments, and recommendations for river management and structural design. The literature review provides an outline and foundation for the research project to characterize extreme bed-load mobility in rivers and streams across the study area. The literature review also provides a basis upon which potential modifications to low-water stream-crossing design in the study area can be made.

Open-File Report↗

USGS2004

Synthesis of rainfall and runoff data used for Texas Department of Transportation Research Projects 0-4193 and 0-4194

In the early 2000s, the Texas Department of Transportation funded several research projects to examine the unit hydrograph and rainfall hyetograph techniques for hydrologic design in Texas for the estimation of design flows for stormwater drainage systems. A research consortium comprised of Lamar University, Texas Tech University, the University of Houston, and the U.S. Geological Survey (USGS), was chosen to examine the unit hydrograph and rainfall hyetograph techniques. Rainfall and runoff data collected by the USGS at 91 streamflow-gaging stations in Texas formed a basis for the research. These data were collected as part of USGS small-watershed projects and urban watershed studies that began in the late 1950s and continued through most of the 1970s; a few gages were in operation in the mid-1980s. Selected hydrologic events from these studies were available in the form of over 220 printed reports, which offered the best aggregation of hydrologic data for the research objectives. Digital versions of the data did not exist. Therefore, significant effort was undertaken by the consortium to manually enter the data into a digital database from the printed record. The rainfall and runoff data for over 1,650 storms were entered. To enhance data integrity, considerable quality-control and quality-assurance efforts were conducted as the database was assembled and after assembly to enhance data integrity. This report documents the database and informs interested parties on its usage.

Texas↗

USGS2004

Empirical, dimensionless, cumulative-rainfall hyetographs developed from 1959-86 storm data for selected small watersheds in Texas

A database of incremental cumulative-rainfall values for storms that occurred in small urban and rural watersheds in north and south central Texas during the period from 1959 to 1986 was used to develop empirical, dimensionless, cumulative-rainfall hyetographs. Storm-quartile classifications were determined from the cumulative-rainfall values, which were divided into data groups on the basis of storm-quartile classification (first, second, third, fourth, and first through fourth combined), storm duration (0 to 6, 6 to 12, 12 to 24, 24 to 72, and 0 to 72 hours), and rainfall amount (1 inch or more). Removal of long leading tails, in effect, shortened the storm duration and, in some cases, affected the storm-quartile classification. Therefore, two storm groups, untrimmed and trimmed, were used for analysis. The trimmed storms generally are preferred for interpretation. For a 12-hour or less trimmed storm duration, approximately 49 percent of the storms are first quartile. For trimmed storm durations of 12 to 24 and 24 to 72 hours, 47 and 38 percent, respectively, of the storms are first quartile. For a trimmed storm duration of 0 to 72 hours, the first-, second-, third-, and fourth-quartile storms accounted for 46, 21, 20, and 13 percent of all storms, respectively. The 90th-percentile curve for first-quartile storms indicated about 90 percent of the cumulative rainfall occurs during the first 20 percent of the storm duration. The 10th-percentile curve for first-quartile storms indicated about 30 percent of the cumulative rainfall occurs during the first 20 percent of the storm duration. The 90th-percentile curve for fourth-quartile storms indicated about 33 percent of the cumulative rainfall occurs during the first 20 percent of the storm duration. The 10th-percentile curve for fourth-quartile storms indicated less than 5 percent of the cumulative rainfall occurs during the first 20 percent of the storm duration. Statistics for the empirical, dimensionless, cumulative-rainfall hyetographs are presented in the report along with hyetograph curves and tables. The curves and tables presented do not present exact mathematical relations but can be used to estimate distributions of rainfall with time for small drainage areas of less than about 160 square miles in urban and small rural watersheds in north and south central Texas.

Texas↗

USGS1990

Synthetic calibration of a Rainfall-Runoff Model

A method for synthetically calibrating storm-mode parameters for the U.S. Geological Survey's Precipitation-Runoff Modeling System is described. Synthetic calibration is accomplished by adjusting storm-mode parameters to minimize deviations between the pseudo-probability disributions represented by regional regression equations and actual frequency distributions fitted to model-generated peak discharge and runoff volume. Results of modeling storm hydrographs using synthetic and analytic storm-mode parameters are presented. Comparisons are made between model results from both parameter sets and between model results and observed hydrographs. Although mean storm runoff is reproducible to within about 26 percent of the observed mean storm runoff for five or six parameter sets, runoff from individual storms is subject to large disparities. Predicted storm runoff volume ranged from 2 percent to 217 percent of commensurate observed values. Furthermore, simulation of peak discharges was poor. Predicted peak discharges from individual storm events ranged from 2 percent to 229 percent of commensurate observed values. The model was incapable of satisfactorily executing storm-mode simulations for the study watersheds. This result is not considered a particular fault of the model, but instead is indicative of deficiencies in similar conceptual models.

Conference Paper↗