Summary of July 2017 Monthly Hydrologic Conditions
Compiled in cooperation with the New Jersey Department of Environmental Protection
Precipitation was above normal at the Atlantic City and Trenton index stations, and below normal for the Newark index station for the reference period 1981-2010. Newark reported 4.36 inches, which is 91.6 percent of normal. Atlantic City reported 10.02 inches, which is 269.35 percent of normal. Trenton reported 5.63 inches, which is 113.74 percent of normal. Total precipitation over the past 12 months was: 47.72 inches at Newark, which is 1.47 inches above normal; 48.16 inches at Atlantic City, which is 6.41 inches above normal; and 39.29 inches at Trenton, which is 7.15 inches below normal.
Combined storage in the thirteen major water supply reservoirs as of July 31 was 71.229 billion gallons (88.1 percent of capacity), which is greater than the average July contents for the reference period 1961-1990. The storage was 1.956 billion gallons less than one month ago and 10.621 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 above the long-term monthly-mean for the reference period 1981-2010 at the Great Egg Harbor River at Folsom and Delaware River at Trenton index stations and below the long-term monthly-mean at the South Branch Raritan River near High Bridge index station. The monthly-mean discharge at South Branch Raritan River near High Bridge was 74.5 ft3/s, 89.3 percent of the long-term mean. The monthly-mean discharge of the Great Egg Harbor River at Folsom was 71.1 ft3/s, 116.0 percent of the long-term mean. The monthly mean discharge of the Delaware River at Trenton was 8,320 ft3/s, 118.1 percent of the long-term mean. The observed daily mean discharge of the Delaware River at Trenton on July 31 was 7,400 ft3/s.
Groundwater levels, as measured in water-table observation wells for the month of July, 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 Morrell 1 index wells and increased from last month at the Vocational School 2 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 22.2 to 29.8 degrees Celsius. Dissolved oxygen ranged from 7.1 to 9.5 milligrams per liter. Specific conductance ranged from 172 to 267 microsiemens per centimeter at 25°C.
Note: The preceding data is preliminary and subject to revision.
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