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Monthly statistical summaries of surface-water temperatures measured at 277 U.S. Geological Survey surface-water sites in New Jersey and adjoining states are presented. Of the 277 sites, 259 are in New Jersey, 10 in Pennsylvania, 6 in New York, and 2 in Delaware. The Pennsylvania, New York, and Delaware sites are included because conditions there reflect conditions in New Jersey streams. Most of the temperatures were measured during 1955-93. Measurements were made prior to 1955, but were included only if available in the computer files.Temperature data from 265 periodic, 37 continuous, and 18 daily temperature records were used to compile monthly statistics for each site. Summaries for periodic and daily records include the number of observations; the maximum, minimum, and median temperatures; and the 25th and 75th percentile temperatures. Summaries for continuous records include the maximum, minimum, and median temperatures. METHODSSurface-water-temperature data from 265 periodic, 37 continuous, and 18 daily stream-temperature records were used to calculate the statistics for the monthly summary tables. Most of the temperature data were collected by the USGS and NJDEP as part of water-quality-monitoring studies. Other temperature data were collected as incidental to other studies. Temperature data are available for more than 1,000 sites in New Jersey; however, only those sites with at least 36 temperatures recorded were included in this report.The USGS has been measuring surface-water temperatures in °C (degrees Celsius) since the late 1970's (Stevens, Ficke, and Smoot, 1975). All temperature values originally recorded in degrees Fahrenheit have been converted to °C. Statistics are reported to 0.5 °C. A Celsius-to-Fahrenheit conversion chart is presented in table 1. Data CollectionWater temperatures were measured at 259 sites in New Jersey, 10 in Pennsylvania, 6 in New York, and 2 in Delaware (fig. 1). Figures 2 through 22 show the site locations in each county of New Jersey. Temperature summaries for sites outside New Jersey are included because the streams are near sites in New Jersey and, therefore, reflect conditions in New Jersey streams. Most of the temperatures used in this report were measured durinp 1955-93; some were measured before 1955.Temperature data used in this report were compiled from the USGS surface-water and water-quality data bases. Periodic and daily temperaturedata are stored in the USGS data base as individual measurements. Continuous temperature data are stored as maximum, minimum, and daily mean temperatures.Periodic temperature data were collected during water-quality and sediment sampling, stream-discharge measurements, or gage inspections. Continuous temperature data were collected as part of a continuous waterquality monitoring program. Daily temperature data were collected typically once a day (usually at the same time each day) for a specified time period as part of a particular water-quality monitoring program. Measurement of Surface-Water TemperaturePeriodic temperatures were m...

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Relations of water quality to streamflow were determined for 18 water-quality constituents at 18 surface-water stations within the drainage basins of the Wallkill and upper Delaware Rivers in New Jersey and vicinity for water years 1976-93. Surface-water-quality and streamflow data were evaluated for trends (through time) in constituent concentrations during high and low flows, and relations between constituent concentration and streamflow, and between constituent load and streamflow, were determined. Median concentrations were calculated for the entire period of study (water years 1976-93) and for the last 5 years of the period of study (water years 1989-93) to determine whether any large variation in concentration exists between the two periods. Medians also were used to determine the seasonal Kendall's tau statistic, which was then used to evaluate trends in concentrations during high and low flows. Trends in constituent concentrations during high and low flows were evaluated to determine whether the distribution of the observations changes through time for intermittent (nonpoint storm runoff) or constant (point sources and ground water) sources, respectively. Highand low-flow trends in concentrations were determined for some constituents at 15 of the 18 water-quality stations; 3 stations have insufficient data to determine trends. Seasonal effects on the relations of concentration to streamflow are evident for 16 of the 18 constituents. Negative slopes of relations of concentration to streamflow, which indicate a decrease in concentration at high flows, predominate over positive slopes because of the dilution of instream concentrations by storm runoff. The slopes of the regression lines of load to streamflow were determined in order to show the relative contributions to the instream load from constant (point sources and ground water) and intermittent (storm runoff) sources. Greater slope values indicate larger contributions from storm runoff to instream load, which most likely indicate an increased relative importance of nonpoint sources. The slopes of load-to-streamflow relations along a stream reach that tend to increase in a downstream direction indicate the increased relative importance of contributions from storm runoff. The slopes of load-to-streamflow relations for several nutrients and dissolved ions increase in the downstream direction at the Wallkill River, Paulins Kill, and Musconetcong River. Likewise, the slopes of load-to-streamflow relations along a stream reach that tend to decrease in a downstream direction indicate the increased relative importance of point sources and groundwater discharge. The slopes of load-to-streamflow relations for several dissolved ions decrease in the downstream direction at the Delaware River. Description of the Study Area The study area, which is in northwestern New Jersey and nearby Pennsylvania and New York, encompasses two river basins-the Wallkill and upper Delaware (fig. 4). Water-quality stations are located within New Jersey unless otherwise indicated. Wallk...

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