New Jersey Water Science Center
Summary of April 2015 Monthly Hydrologic Conditions
Compiled in cooperation with the New Jersey Department of Environmental Protection
Precipitation was below normal at all three index stations for the reference period 1981-2010. Newark reported 1.67 inches, which is 39.76 percent of normal. Atlantic City reported 2.55 inches, which is 70.25 percent of normal. Trenton reported 2.50 inches, which is 70.62 percent of normal. Total precipitation over the past 12 months was: 42.79 inches at Newark, which is 3.46 inches below normal; 53.69 inches at Atlantic City, which is 11.94 inches above normal; and 40.23 inches at Trenton, which is 6.21 inches below normal.
Combined storage in the thirteen major water supply reservoirs as of April 30 was 75.421 billion gallons (93.2 percent of capacity), which is greater than the average April contents for the reference period 1961-1990. The storage was 2.895 billion gallons greater than one month ago and 2.855 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, Charlotteburg Reservoir, Echo Lake, Wanaque Reservoir and Spruce Run Reservoir.
Streamflow was below the long-term monthly-mean for the reference period 1981-2010 at the South Branch Raritan River near High Bridge and Delaware River at Trenton index stations, and equal to the long-term monthly-mean for the Great Egg Harbor River at Folsom index station. The monthly-mean discharge at South Branch Raritan River near High Bridge was 141 ft3/s, 69.8 percent of the long-term mean. The monthly-mean discharge of the Great Egg Harbor River at Folsom was 120 ft3/s, 100.0 percent of the long-term mean. The monthly mean discharge of the Delaware River at Trenton was 19,560 ft3/s, 92.2 percent of the long-term mean. The observed daily mean discharge of the Delaware River at Trenton on April 30 was 10,600 ft3/s.
Groundwater levels, as measured in water-table observation wells for the month of April, were above normal at the Morrell 1 and Vocational School 2 index wells, and below normal at the Readington School 11 index well. Levels decreased from last month at all three index wells. Levels were lower than one year ago at the Readington School 11 and Morrell 1 index well, and were higher than one year ago at the Vocational School 2 index well.
Water-quality parameters collected from the Delaware River at Trenton were within the range of historical monthly values. Water temperature ranged from 4.9 to 14.8 degrees Celsius. Dissolved oxygen ranged from 10.1 to 13.4 milligrams per liter. Specific conductance ranged from 124 to 241 microsiemens per centimeter at 25°C.
Note: The preceding data is preliminary and subject to revision.
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