Summary of April 2017 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 3.49 inches, which is 83.10 percent of normal. Atlantic City reported 2.97 inches, which is 81.82 percent of normal. Trenton reported 3.16 inches, which is 89.27 percent of normal. Total precipitation over the past 12 months was: 43.16 inches at Newark, which is 3.09 inches below normal; 45.78 inches at Atlantic City, which is 4.03 inches above normal; and 36.84 inches at Trenton, which is 9.60 inches below normal.
Combined storage in the thirteen major water supply reservoirs as of April 30 was 75.619 billion gallons (93.5 percent of capacity), which is greater than the average April contents for the reference period 1961-1990. The storage was 5.944 billion gallons greater than one month ago and 2.836 billion gallons greater 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 Folsom River at Folsom index stations, and above the long-term monthly-mean at the the Delaware River at Trenton index station. The monthly-mean discharge at South Branch Raritan River near High Bridge was 183 ft3/s, 90.6 percent of the long-term mean. The monthly-mean discharge of the Great Egg Harbor River at Folsom was 83.7 ft3/s, 69.8 percent of the long-term mean. The monthly mean discharge of the Delaware River at Trenton was 27,950 ft3/s, 131.7 percent of the long-term mean. The observed daily mean discharge of the Delaware River at Trenton on April 30 was 12,500 ft3/s.
Groundwater levels, as measured in water-table observation wells for the month of April, were above normal at the Readington School 11 and Morrell 1 index wells, and below normal at the Vocational School 2 index well. Levels decreased from last month at the Readington School 11 and Vocational School 2 index wells and increased from last month at the Morrell 1 index well. Levels were higher than one year ago at the Readington School 11 and Morrell 1 index wells and lower 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 5.7 to 17.8 degrees Celsius. Dissolved oxygen ranged from 9.2 to 12.4 milligrams per liter. Specific conductance ranged from 117 to 244 microsiemens per centimeter at 25°C.
Note: The preceding data is preliminary and subject to revision.
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