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Robert M. Hirsch

Publications and source records attributed to Robert M. Hirsch.

70 records · Page 4Linked to original sources
USGS1995

The stream-gaging program of the U.S. Geological Survey

The U.S. Geological Survey stream-gaging program provides streamflow data for a variety of purposes. The uses of streamflow data are described, and the growth of the stream-gaging program is related to legislation and the need to manage the Nation's water resources more effectively. A brief description is provided of the data-collection processes, computation of streamflow records, dissemination of data, and the nationwide evaluations of the stream-gaging program. Finally, the challenges for maintaining a viable stream-gaging program are described.

Circular↗
USGS1986

CONCEPTUAL DESIGN OF THE SURFACE WATER COMPONENT OF THE NATIONAL WATER QUALITY ASSESSMENT (NAWQA) PROGRAM.

The US Geological Survey started, in a pilot phase, a program to provide nationally consistent information on the status and trends in the quality of the nation's fresh water. The program also intends to identify and describe the relationships between both the status and trends in water quality as they relate to natural factors, and the history of land-use, and land- and waste-management practices. The program is organized into hydrologically based study units and, for the study of surface water, involves a combination of fixed-station, synoptic and intensive study approaches. Network design considerations are discussed.

Conference Paper↗
USGS1985

Trend analysis of weekly acid rain data, 1978-83

There are 19 stations in the National Atmospheric Deposition Program which operated over the period 1978-83 and were subsequently incorporated into the National Trends Network in 1983. The precipitation chemistry data for these stations for this period were analyzed for trend, spatial correlation, seasonality, and relationship to precipitation volume. The intent of the analysis was to provide insights on the sources of variation in precipitation chemistry and to attempt to ascertain what statistical procedures may be most useful for ongoing analysis of the National Trends Network data. The Seasonal Kendall test was used for detection of trends in raw concentrations of dissolved constituents, pH and specific conductance, and residuals of these parameters from regression analysis. Forty-one percent of the trends detected in the raw concentrations were downtrends, 4 percent were uptrends, and 55 percent showed no trends at a = 0.2. At a more restrictive significance level of a = 0.05, 24 percent of the trends detected were downtrends, 2 percent were uptrends, and 74 percent showed no trends. The two constituents of greatest interest in terms of human generated emissions and environmental effects, sulfate and nitrate, showed only downtrends, and sulfate showed the largest decreases in concentration per year of all the ions tested.

Water-Resources Investigations Report↗
USGS1983

Nonparametric tests for trends in water-quality data using the statistical analysis system

Two nonparametric procedures to test for trends in water-quality data (SEASKEN AND SEASRS) have been developed for the Statistical Analysis System* (SAS). The procedure SEASKEN tests for a monotonic trend in time by a modified form of Kendall's tau, the Seasonal Kendall test. The procedure SEASRS tests for a step trend between two different periods in a time series using a modified form of the Wilcoxon (Mann-Whitney) rank sum test, the Mann-WhitneyWilcoxon rank sum test for seasonal data. Examples are presented using the two procedures. The source code and user's guide for each of the two procedures are also presented. Procedures for flow adjusting water-quality data by the SAS procedures REG and SYSREG and techniques for plotting water-quality data as a time series by the SAS procedure PLOT are presented. Additionally, examples are presented to demonstrate the use of the U.S. Geological Survey procedures QWRETR, DVRETR, QWSAS, and DVINPUT to retrieve data from the Geological Survey WATSTORE system and make it available to SAS.

Open-File Report↗
USGS1982

Investigation of trends in flooding in the Tug Fork basin of Kentucky, Virginia, and West Virginia

Statistical analysis indicates that the average size of annual-flood peaks of the Tug Fork (Ky., Va., and W. Va.) has been increasing. However, additional statistical analysis does not indicate that the flood levels that were exceeded typically once or twice a year in the period 1947-79 are any more likely to be exceeded now than in 1947. Possible trends in streamchannel size also are investigated at three locations. No discernible trends in channel size are noted. Further statistical analysis of the trend in the size of annual-flood peaks shows that much of the annual variation is related to local rainfall and to the 'natural' hydrologic response in a relatively undisturbed subbasin. However, some statistical indication of trend persists after accounting for these natural factors, though it is of borderline statistical significance. Further study in the basin may relate flood magnitudes to both rainfall and to land use.

Water Supply Paper↗
USGS1981

Estimating probabilities of reservoir storage for the upper Delaware River Basin

A technique for estimating conditional probabilities of reservoir system storage is described and applied to the upper Delaware River Basin. The results indicate that there is a 73 percent probability that the three major New York City reservoirs (Pepacton, Cannonsville, and Neversink) would be full by June 1, 1981, and only a 9 percent probability that storage would return to the "drought warning" sector of the operations curve sometime in the next year. In contrast, if restrictions are lifted and there is an immediate return to normal operating policies, the probability of the reservoir system being full by June 1 is 37 percent and the probability that storage would return to the "drought warning" sector in the next year is 30 percent.

Delaware, New Jersey, New York, Pennsylvania↗
USGS1980

An economic analysis of selected strategies for dissolved-oxygen management; Chattahoochee River, Georgia

A method for evaluating the cost-effectiveness of alternative strategies for dissolved-oxygen (DO) management is demonstrated, using the Chattahoochee River, GA., as an example. The conceptual framework for the analysis is suggested by the economic theory of production. The minimum flow of the river and the percentage of the total waste inflow receiving nitrification are considered to be two variable inputs to be used in the production of given minimum concentration of DO in the river. Each of the inputs has a cost: the loss of dependable peak hydroelectric generating capacity at Buford Dam associated with flow augmentation and the cost associated with nitrification of wastes. The least-cost combination of minimum flow and waste treatment necessary to achieve a prescribed minimum DO concentration is identified. Results of the study indicate that, in some instances, the waste-assimilation capacity of the Chattahoochee River can be substituted for increased waste treatment; the associated savings in waste-treatment costs more than offset the benefits foregone because of the loss of peak generating capacity at Buford Dam. The sensitivity of the results to the estimates of the cost of replacing peak generating capacity is examined. It is also demonstrated that a flexible approach to the management of DO in the Chattahoochee River may be much more cost effective than a more rigid, institutional approach wherein constraints are placed on the flow of the river and(or) on waste-treatment practices. (USGS)

Georgia↗
USGS1979

An economic analysis of selected strategies for dissolved oxygen management: Chattahoochee River, Georgia

Using the Chattahoochee River as an example, a method for evaluating the cost-effectiveness of alternative strategies for dissolved oxygen (DO) management is demonstrated. The conceptual framework for the analysis is suggested by the economic theory of production. The minimum flow of the River and the percentage of the total waste inflow receiving nitrification are considered to be two variable inputs to be used in the production of a given minimum concentration of DO in the River. Each of the inputs has a cost: the loss of dependable peak hydroelectric generating capacity at Buford Dam associated with flow augmentation and the cost associated with nitrification of wastes. The least-cost combination of minimum flow and waste treatment to achieve a prescribed minimum DO concentration is identified. Results indicate that, in some instances, the waste assimilative capacity of the Chattahoochee River can be substituted for increased waste treatment with the associated savings in waste treatment costs more than offsetting the benefits foregone due to the loss of peak generating capacity at Buford Dam. The sensitivity of the results to the estimates of the cost of replacing peak generating capacity is examined. It is also demonstrated that a flexible approach to the management of DO in the Chattahoochee River may be much more cost-effective than a more rigid, institutional approach wherein constraints are placed on the flow of the River and/or waste treatment practices.

Georgia↗
USGS1978

Risk analyses for a water-supply system; Occoquan Reservoir, Fairfax and Prince William counties, Virginia

This report demonstrates two techniques for evaluating risks in the operation of a water-supply system. Both rely on reconstructed historical streamflow data to develop estimates of the probabilities of certain specific events occurring in the future. These techniques are applied to the Occoquan Reservoir which was experiencing an unprecedented low level of storage in the autumn of 1977. The two techniques are used respectively to evaluate the overall adequacy of the existing reservoir and to evaluate the risks in the 1977 crisis. In the first technique, the general risk analysis model (GRAM), simulations of the reservoir's contents are carried out under a set of assumptions about withdrawal rates and emergency procedures. The results of the GRAM simulation for the Occoquan Reservoir are in the form of estimates of the probabilities that in any year certain emergency procedures will have to be invoked. These estimates are given for a range of rates of withdrawals and for four different stages of emergency actions. Also given are the estimated probabilities of entering emergency conditions in one year given that an emergency had occurred in the previous year. Due to the year-to-year persistence of low flows, these latter (conditional) probabilities are higher than the former (marginal) probabilities. The second technique used is position analysis. In this procedure probability distributions of future storages are estimated under existing storage conditions and an assumed rate of withdrawal from the reservoir. The position analysis which was initialized at the October 1, 1977, conditions indicates that the probability of entering a Stage III emergency (the prohibition of all uses of water nonessential to life, health, and safety) in the autumn of 1977 or winter of 1978 was 10 percent at that time. However, with a reduction in water use by 8 million gallons per day, this probability would have fallen to 4 percent. If a long reconstructed historical streamflow record is available to a water supply agency, then the agency will have the capability to undertake its own risk analyses. It can carry out comparisons of alternative operating policies by using techniques such as GRAM. It can also evaluate short-term risk of different plans of operation during crisis situations by using position analysis.

Virginia↗