New Jersey Water Science Center
Summary of July 2007 Monthly Hydrologic Conditions
Compiled in cooperation with the New Jersey Department of Environmental Protection
Precipitation was above normal at the Newark index station, and below normal at the Atlantic City and Trenton index stations. Newark reported 6.71 inches, which is 143 percent of normal. Atlantic City reported 1.77 inches, which is 45.8 percent of normal. Trenton reported 3.17 inches, which is 74.1 percent of normal. Total precipitation over the past 12 months was: 56.62 inches at Newark, which is 10.37 inches above normal; 48.07 inches at Atlantic City, which is 7.48 inches above normal; and 49.72 inches at Trenton, which is 8.33 inches above normal.
Combined storage in the thirteen major water supply reservoirs as of July 31 was 63.7 billion gallons (79.2 percent of capacity), which is slightly greater than the average July contents for the reference period 1961-1990. The storage was 6.36 billion gallons less than one month ago and 9.50 billion gallons less than one year ago. The thirteen major water supply reservoirs are as follows: Lake Tappan, Woodcliff Lake, Oradell Reservoir, DeForest Lake, Splitrock Reservoir, Boonton Reservoir, Canistear Reservoir, Oak Ridge Reservoir, Clinton Reservoir, Charlottesburg Reservoir, Echo Lake, Wanaque Reservoir and Spruce Run Reservoir.
Streamflow was below normal at all three index stations. The monthly-mean discharge at South Branch Raritan River near High Bridge was 87.2 ft3/s, 95 percent of normal. The monthly-mean discharge of the Great Egg Harbor River at Folsom was 50.1 ft3/s, 76 percent of normal. The monthly mean discharge of the Delaware River at Trenton was 5,088 ft3/s, 70 percent of normal. The observed daily mean discharge of the Delaware River at Trenton on July 31 was 7,710 ft3/s.
Groundwater levels, as measured in water-table observation wells for the month of July, were below normal at the Readington School 11 index well, and above normal at the Morrell 1 and Vocational School 2 index wells. Levels decreased from last month and were lower than one year ago at the Readington School 11 and Vocational School 2 wells. Levels increased from last month and were higher than one year ago at the Morrell 1 well.
Water quality parameters collected from the Delaware River at Trenton were within recorded historical monthly extremes. Water temperature ranged from 21.9 to 29.8 degrees Celsius. Dissolved oxygen ranged from 6.0 to 9.5 milligrams per liter. Specific conductance ranged from 177 to 262 microsiemens per centimeter at 25°C.
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