Prepared in Cooperation with the NEW JERSEY DEPARTMENT of ENVIRONMENTAL PROTECTION, DIVISION of WATER RESOURCES
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UNITED STATES DEPARTMENT OF THE INTERIOR GEOLOGICAL SURVEY LOW-FLOW CHARACTERISTICS AND FLOW DURATION OF NEW JERSEY STREAMS By Brian D. Gillespie and Robert D. Sehopp Open-File Report 81-1110 Prepared in cooperation with the NEW JERSEY DEPARTMENT OF ENVIRONMENTAL PROTECTION, DIVISION OF WATER RESOURCES Trenton, New Jersey January 1982 UNITED STATES DEPARTMENT OF THE INTERIOR JAMES G. WATT, Secretary GEOLOGICAL SURVEY Dallas L. Peck, Director Tor additional information, write to: U.S. Geological Survey Room 430, Federal Building 402 East State Street Trenton, New Jersey 08608 Ill CONTENTS Page Abstract................................................... 1 Introduction............................................... 1 Method of study ............................................ 2 Flow-duration analysis..................................... 5 Low-flow frequency analysis................................ 7 Continuous gaging stations............................... 7 Partial-record sites..................................... 10 Selected references........................................ 14 Low-flow characteristics of gaging sites................... 15 Hudson, Hackensack, Passaic, Elizabeth, and Rahway River basins.............................................. 17 Station index, in downstream order..................... 19 Station descriptions and data.......................... 21 Raritan River basin...................................... 53 Station index, in downstream order..................... 55 Station descriptions and data.......................... 57 Atlantic Coastal basins (Upper).......................... 85 Station index, in downstream order..................... 87 Station descriptions and data.......................... 88 Atlantic Coastal basins (Lower).......................... 99 Station index, in downstream order..................... 101 Station descriptions and data.......................... 102 Delaware Bay basins...................................... 113 Station index, in downstream order..................... 115 Station descriptions and data.......................... 116 Delaware River basin (Upper)............................. 121 Station index, in downstream order..................... 123 Station descriptions and data.......................... 124 Delaware River basin (Lower)............................. 143 Station index, in downstream order..................... 145 Station descriptions and data.......................... 146 Station index, in alphabetical order....................... 160 ILLUSTRATIONS Figure 1. Sample computer printout of low-flow data for Whippany River at Morristown, New Jersey..... 3 2. Sample computer printout of flow-duration data for Whippany River at Morristown, New Jersey. 4 3. Flow-duration curve for Whippany River at Morristown, New Jersey....................... 6 4. Low-flow frequency curves for Whippany River at Morristown, New Jersey....................... 8 IV ILLUSTRATIONS--Continued 5. Sample low-flow summary for Whippany River at Morristown, New Jersey..................... 6. Sample of computer plot of low-flow correlation curve for Whippany River near Morristown, New Jersey ................................... 11 7- Sample statistical summary of low-flow correlation data for Whippany River near Morristown, New Jersey ....................... 12 8. Index map of major New Jersey drainage basins.. 16 9. Map segment 1 showing site locations in the Hudson, Hackensack, Passaic, Elizabeth, and Rahway River basins. ......................... 18 10. Map segment 2 showing site locations in the Raritan River basin. ......................... 54 11. Map segment 3 showing site locations in the upper part of the Atlantic Coastal basin..... 86 12. Map segment 4 showing site locations in the lower part of the Atlantic Coastal basin..... 100 13. Map segment 5 showing site locations in the Delaware Bay basin. .......................... 114 14. Map segment 6 showing site locations in the upper part of the Delaware River basin....... 122 15. Map segment 7 showing site locations in the lower part of the Delaware River basin....... 144 VI GLOSSARY Continued Low-flow frequency curve.--A graph showing the relation between the magnitude and frequency of the annual lowest mean flow for a given number of consecutive days. Low-flow frequency is expressed as the average interval, in years, between recurrence of an annual minimum flow less than that shown by the magnitude scale. The low-flow frequency relation is commonly presented as a family of curves with a separate curve for each number of consecutive days. Partial-record site.--A location on a stream, canal, lake or reservoir where limited streamflow data, usually consisting of streamflow measurements, are collected over a period of years for use in hydrologic analysis. Regulation. The artificial manipulation of the flow of a stream, such as, by the operation of reservoirs, cranberry bogs, or artificial lakes. Recurrence interval. The time interval, in years, within which a given hydrologic event will, on the average, be less or more than a given value one time. It is the reciprocal of the probability that the given hydrologic event will not be exceeded or will be exceeded in any one year. For example, a 20-year low-flow is one that has a 5 percent chance of not being exceeded in any one year. Water year. The 12-month period, October 1 through September 30, designated by the calendar year in which it ends. GLOSSARY Some hydrologic and statistical terms and concepts defined in the context in which they are used in this report are listed below: Climatic year. The 12-month period beginning April 1 of the year indicated. This period is used because it splits the usual high-water period of the year and allows the low-water season to occur entirely in 1 year. Cubic foot per second (ft 3 /s or cu ft/s) . The rate of discharge equivalentto a stream whose channel is 1 square foot in cross-sectional area and whose average velocity is 1 foot per second. Diversion. The taking of water from a stream or other body of water upstream from the gaging station into a canal, pipe, or other conduit. Drainage area. Computed at specified locations, it is that area, measured in a horizontal plane, which is so enclosed by a topographic divide that direct surface water from precipitation normally would drain by gravity into the stream above the specified point. Flow, natural. The flow of a stream as it occurs under natural conditions; that is, not subjected to any regulation or diversions. Flow__, regulated. The flow of a stream that has been subjected to any artificial or man-made storage, augmentation or diversions. Flow-duration curve. A cumulative-frequency curve that shows the percentage of time that specified discharges are exceeded. The flow-duration curve is based on the total period of record, but the chronologic sequence of flows is omitted from consideration in the preparation of the curve. Therefore, it is impossible to tell from the flow-duration curve alone whether varying periods of low flow all occurred during one drought period or were scattered over a number of years. The flow-duration curve is, however, useful for studying the flow characteristics of a stream over its entire range of discharge. Gaging station. A site on a stream, canal, lake or reservoir where systematic observations of gage height or discharge are obtained. VII FACTORS FOR CONVERTING INCH-POUND UNITS TO METRIC (SI) UNITS For those readers who may prefer to use metric units rather than inch-pound units, the conversion factors for the terms used in this report are listed below: Multiply inch-pound unit By To obtain metric units cubic foot per second 0.02832 cubic meter per second (ft 3 /s or cu ft/s) (mVs or cu m/s) cubic foot per second per 0.01093 cubic meter per second square mile per square kilometer (ftVs)/mi 2 or (m 3 /s)/km 2 or cu ft/s/sq mi cu m/s/sq km foot (ft) 0.3048 meter (m) mile (mi) 1.609 kilometer (km) square mile (mi 2 or 2.590 square kilometer (km2 sq mi) or sq km) "LOW-FLOW CHARACTERISTICS AND FLOW DURATION OF NEW JERSEY STREAMS By Brian D. Gillespie and Robert D. Schopp ABSTRACT Low-flow frequency and flow-duration data for 400 contin uous-record and partial-record gaging stations in New Jersey are tabulated in this report. The amount of data analyzed at each site varies from the complete daily discharge record for the con tinuous-record gaging stations, some of which have been in opera tion for over 50 years, to limited discharge measurements for partial-record sites. Daily discharges through 1975 for continuous-record sta tions with 7 or more years of record were analyzed by digital computer. From these computer summaries, low-flow frequency tables for all gaging stations on unregulated streams with 10 or more years of record were tabulated. Flow-duration tables were also compiled for streams with at least 7 years of streamflow record. For continuous-record gaging stations with less than 10 years of record, for highly regulated streams, and for partial- record sites, only observed or estimated annual minimum mean discharges for 7 consecutive days with recurrence intervals of 2 and 10 years are given. INTRODUCTION As the population increases, more water is needed for homes, industry, sanitation, irrigation, and recreation. Planning for present or future water supply needs requires information on the magnitude and frequency of available streamflow. This infor mation is often supplied by low-flow frequency and flow-duration data. This report presents low-flow frequency and