USGS Home Contact USGS Search USGS

Publications— Open-File Report

Use of Low-Flow Trend and Transfer-Function Models to Determine Relation of Low Flows to Regional Urbanization and Precipitation, Rahway River Basin, New Jersey,
1940-91

U.S. Geological Survey Open-File Report 99-257

Prepared in cooperation with the New Jersey Department of Environmental Protection

By Thomas H. Barringer, Robert G. Reiser, and Curtis V. Price

View the report in Portable Document Format (PDF) OFR 99-257 (1.43 MB)

Abstract

The Rahway River Basin in northern New Jersey has become heavily urbanized. The importance of the Rahway River as a water-supply source for the region led to an investigation of trends in the river's low-flow characteristics over time and their relation to regional urbanization and precipitation. Since 1950, low flows at a stream-gaging station near Springfield, N.J., increasingly have tended to exceed those at a station at Rahway. Polynomial-trend models for three measures of low-flow difference between the two stations during 1940-91 show trends in all three measures, indicating that they have changed significantly in level during the study period. Transfer-function models indicate that differences in low flows between the two gaging stations are significantly related to measures of basin urbanization and regional precipitation. A rough water budget for the inter-gage part of the basin confirms these results.

Table of Contents

Abstract
Introduction
     Purpose and Scope
     Description of Study Area
     Modeling Methods
          Trend Models
          Transfer-Function Models
     Selection and Description of Low-Flow Characteristics and Independent Variables
          Low-Flow Chracteristics
               Annual Median Base-Flow Difference
               Annual Mean 7-Day Low-Flow Difference
               Difference in Annual Number of Days Below Minimum Passing Flow
          Independent Variables
               Regional Precipitation
               Annual Ground- and Surface-Water Withdrawals
               Annual Sewage Output
               Population-Density Estimates
               Union County Road Mileage
               Union County Building Permits
Trends in Low-Flow Difference and Correlations with Urbanization and Precipitation
     Trends in Low-Flow Difference
          Annual Median Base-Flow Difference
          Annual Median 7-Day Low-Flow Difference
          Difference in Annual Number of Days Below Minimum Passing Flow
     Transfer-Function Models
          Annual Median Base-Flow Difference
          Annual Mean 7-Day Low-Flow Difference
          Difference in Annual Number of Days Below Minimum Passing Flow
          Other Models
Comparison of Trends in Low-Flow Differences
Relations of Low-Flow-Difference Characteristics to Urbanization and Precipitation
Summary and Conclusions
References Cited

Suggested citation:
Barringer, T.H., Reiser, R.G., and Price, C.V., 2000, Use of low-flow trend and transfer-function models to determine relation of low flows to regional urbanization and precipitation, Rahway River Basin, New Jersey, 1940-91: U.S. Geological Survey Open-File Report 99-257, 24 p.

If you have Adobe® Acrobat® or Adobe® Acrobat®Reader® installed on your computer, you may view and print the PDF version of this report. Acrobat Reader, is a free download from Adobe Systems Incorporated.

View the report in Portable Document Format (PDF) OFR 99-257 (1.43 MB)

For more information about USGS activities in New Jersey contact:
Director
USGS New Jersey Water Science Center
810 Bear Tavern Road, Suite 206
West Trenton, NJ 08628
Telephone: (609) 771-3900
Fax: (609) 771-3915
or access the USGS Water Resources of New Jersey home page at:
http://nj.usgs.gov/.