New Jersey Water Science Center
Summary of July 2010 Monthly Hydrologic Conditions
Compiled in cooperation with the New Jersey Department of Environmental Protection
Precipitation was below normal at all three index stations. Newark reported 1.93 inches, which is 41.2 percent of normal. Atlantic City reported 3.12 inches, which is 80.8 percent of normal. Trenton reported 4.12 inches, which is 96.3 percent of normal. Total precipitation over the past 12 months was: 47.5 inches at Newark, which is 1.29 inches above normal; 62.4 inches at Atlantic City, which is 21.9 inches above normal; and 52.1 inches at Trenton, which is 10.7 inches above normal.
Combined storage in the thirteen major water supply reservoirs as of July 31 was 60.08 billion gallons (74.3 percent of capacity), which is lower than the average July contents for the reference period 1961-1990.; The storage was -8.079 billion gallons lower than one month ago and -17.569 billion gallons lower 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 63.1 ft3/s, 68.8 percent of normal. The monthly-mean discharge of the Great Egg Harbor River at Folsom was 61.3 ft3/s, 93.4 percent of normal. The monthly mean discharge of the Delaware River at Trenton was 3948 ft3/s, 54.2 percent of normal. The observed daily mean discharge of the Delaware River at Trenton on July 31 was 3090 ft3/s.
Ground-water levels, as measured in water-table observation wells for the month of July were below normal at the Readington School 11 and Morrell 1 index wells, and above normal at the Vocational School 2 index well. Levels increased from last month at the Morrell 1 index well and decreased from last month at the Readington School 11 and Vocational School 2 index wells. Levels were higher than one year ago at the Vocational School 2 index well, and were lower than one year ago at the Readington School 11 and Morrell 1 index wells.
Water quality parameters collected from the Delaware River at Trenton were within recorded historical monthly extremes. Water temperature ranged from 22.9 to 30.9 degrees Celsius. Dissolved oxygen ranged from 6.3 to 15.7 milligrams per liter. Specific conductance ranged from 215 to 277 microsiemens per centimeter at 25°C.Note: The preceding data is preliminary and subject to revision.
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