Summary of December 2016 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 2.91 inches, which is 76.38 percent of normal. Atlantic City reported 3.29 inches, which is 89.16 percent of normal. Trenton reported 2.65 inches, which is 71.62 percent of normal. Total precipitation over the past 12 months was: 38.41 inches at Newark, which is 7.84 inches below normal; 45.02 inches at Atlantic City, which is 3.27 inches above normal; and 34.82 inches at Trenton, which is 11.62 inches below normal.
Combined storage in the thirteen major water supply reservoirs as of December 31 was 47.344 billion gallons (58.5 percent of capacity), which is less than the average December contents for the reference period 1961-1990. The storage was 7.477 billion gallons greater than one month ago and 9.361 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 all three index stations. The monthly-mean discharge at South Branch Raritan River near High Bridge was 54.2 ft3/s, 35.7 percent of the long-term mean. The monthly-mean discharge of the Great Egg Harbor River at Folsom was 55.4 ft3/s, 56.6 percent of the long-term mean. The monthly mean discharge of the Delaware River at Trenton was 6,755 ft3/s, 44.6 percent of the long-term mean. The observed daily mean discharge of the Delaware River at Trenton on December 31 was 6,870 ft3/s.
Groundwater levels, as measured in water-table observation wells for the month of December, were below normal at the Readington School 11 and Vocational School 2 index wells, and above normal at the Morrell 1 index well. Levels increased from last month and were lower than one year ago at all three index wells.
Water-quality parameters collected from the Delaware River at Trenton were within the range of historical monthly values, except for a new high in specific conductance. Water temperature ranged from 0.3 to 10.8 degrees Celsius. Dissolved oxygen ranged from 11.3 to 16.1 milligrams per liter. Specific conductance ranged from 169 to 324 microsiemens per centimeter at 25°C.
Note: The preceding data is preliminary and subject to revision.
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