New Jersey Water Science Center
Summary of December 2009 Monthly Hydrologic Conditions
Compiled in cooperation with the New Jersey Department of Environmental Protection
Precipitation was above normal at all three index stations. Newark reported 7.13 inches, which is 200 percent of normal. Atlantic City reported 9.99 inches, which is 317 percent of normal. This has been the wettest December on record and the second snowiest with 12.6 inches of snow at Atlantic City. Trenton reported 6.42 inches, which is 190 percent of normal, it is tied with 1879 for the seventh wettest December on record. Total precipitation over the past 12 months was: 47.93 inches at Newark, which is 1.68 inches above normal; 61.55 inches at Atlantic City, which is 20.96 inches above normal; and 53.62 inches at Trenton, which is 12.23 inches above normal.
Combined storage in the thirteen major water supply reservoirs as of December 31 was 73.62 billion gallons (91.0 percent of capacity), which is higher than the average December contents for the reference period 1961-1990. The storage was 7.304 billion gallons higher than one month ago and -0.216 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 above normal at all three index stations. The monthly-mean discharge at South Branch Raritan River near High Bridge was 231 ft3/s, 149 percent of normal. The monthly-mean discharge of the Great Egg Harbor River at Folsom was 234 ft3/s, 236 percent of normal. The monthly mean and the maximum mean daily flow of 683 ft3/s on December 28 are the highest recorded at Great Egg Harbor River at Folsom since record started in 1925. The monthly mean discharge of the Delaware River at Trenton was 19890 ft3/s, 139 percent of normal. The observed daily mean discharge of the Delaware River at Trenton on December 31 was 19400 ft3/s.
Ground-water levels, as measured in water-table observation wells for the month of December were above normal at all three index wells. Levels increased from last month. Levels were higher than one year ago at the Readington School 11 and Vocational School 2 index wells, but were lower than one year ago at the Morrell 1 index well. The water level at the Vocational School 2 index well is the highest recorded for the month of December since water level data collection started in March 1972.
Water quality parameters collected from the Delaware River at Trenton were within recorded historical monthly extremes. Water temperature ranged from 0.5 to 9.0 degrees Celsius. Dissolved oxygen ranged from 11.3 to 14.6 milligrams per liter. Specific conductance ranged from 129 to 232 microsiemens per centimeter at 25°C.Note: The preceding data is preliminary and subject to revision.
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