Summary of May 2017 Monthly Hydrologic Conditions
Compiled in cooperation with the New Jersey Department of Environmental Protection
Precipitation was above normal at all three index stations for the reference period 1981-2010. Newark reported 7.24 inches, which is 177.02 percent of normal. Atlantic City reported 7.52 inches, which is 224.48 percent of normal. Trenton reported 5.25 inches, which is 120.14 percent of normal. Total precipitation over the past 12 months was: 46.55 inches at Newark, which is 0.30 inches above normal; 46.62 inches at Atlantic City, which is 4.87 inches above normal; and 38.54 inches at Trenton, which is 7.90 inches below normal.
Combined storage in the thirteen major water supply reservoirs as of May 31 was 77.560 billion gallons (95.9 percent of capacity), which is greater than the average May contents for the reference period 1961-1990. The storage was 1.942 billion gallons more than one month ago and 3.008 billion gallons more 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 index station, and above the long-term monthly-mean for the Great Egg Harbor River at Folsom and Delaware River at Trenton index stations. The monthly-mean discharge at South Branch Raritan River near High Bridge was 131 ft3/s, 85.6 percent of the long-term mean. The monthly-mean discharge of the Great Egg Harbor River at Folsom was 116 ft3/s, 125.0 percent of the long-term mean. The monthly mean discharge of the Delaware River at Trenton was 13,900 ft3/s, 100.6 percent of the long-term mean. The observed daily mean discharge of the Delaware River at Trenton on May 31 was 10,300 ft3/s.
Groundwater levels, as measured in water-table observation wells for the month of May, were above normal at the Readington School 11 and Morrell 1 index wells and below normal at the Vocational School 2 index well. Levels increased from last month at the Readington School 11 and Vocational School 2 index wells, but decreased from last month at the Morrell 1 index well. Levels were higher than one year ago at the Readington School 11 index well, and lower than one year ago at the Morrell 1 and Vocational School 2 index wells.
Water-quality parameters collected from the Delaware River at Trenton were within the range of historical monthly values. Water temperature ranged from 11.9 to 21.9 degrees Celsius. Dissolved oxygen ranged from 8.4 to 11.6 milligrams per liter. Specific conductance ranged from 118 to 216 microsiemens per centimeter at 25°C.
Note: The preceding data is preliminary and subject to revision.
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