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Most Recent Hydrologic Conditions Report
March 15, 2016
Precipitation

The observed precipitation for the Delaware River Basin above Montague, New Jersey for the period January 1, 2016 through March 14, 2016 was 6.64 inches, or 0.58 inches below normal. For the period January 1, 2016 through March 14, 2016, the observed precipitation for the Delaware River Basin above Trenton, New Jersey was 7.7 inches, which is normal for this period. Also through March 14, the observed precipitation for Wilmington, Delaware was 7.94 inches, or 1.04 inches above normal.

The attached table summarizes precipitation for 2015 and 2016 for select stations in the Delaware River Basin.

Precipitation Departure Maps (National Weather Service Middle Atlantic River Forecast Center's Web Site)

Streamflow

The average observed streamflow of the Delaware River at Montague, New Jersey in February 2016 was 8,436 cubic feet per second (cfs), or 167-percent of the long-term average for the month. The average observed streamflow of the Delaware River at Trenton, New Jersey in February 2016 was 21,742 cfs, or 185-percent of the long-term average for the month. 

During March 1-14, the average observed streamflow of the Delaware River at Montague was 7,378 cfs, or 84-percent of the long-term average for the month. Similarly, the average streamflow at Trenton was 14,986 cfs, or 82-percent of the long-term average for the month.

Below are graphical presentations of daily mean streamflows at Montague and Trenton for the 365-day period ending March 14, 2016.

Reservoirs

Lower Basin

Lower Basin Reservoir Storage as of March 15, 2016:
Beltzville

13.51 billion gallons (bg) usable, or 100.1% of usable storage

Blue Marsh

4.54 bg usable, or 102.5% of winter pool usable storage

Merrill Creek

14.19 bg usable, or 90.5% of usable storage

Upper Basin

New York City (NYC) Delaware Basin Reservoir Storage as of March 15, 2016:
Pepacton

129.0 bg usable, or 92.1% of usable storage

Cannonsville

91.4 bg usable, or 95.5% of usable storage

Neversink

32.8 bg usable, or 93.9% of usable storage

Total

253.2 bg usable, or 93.5% of usable storage

The long-term median storage for the NYC Delaware basin reservoirs for March 15 is 242.7 bg, or 89.6% percent of usable storage.

Attached is a graphical presentation of the reservoir storage levels from January 2015 to the present.

Groundwater

The table below displays the current status (March 15, 2016) of groundwater levels for 14 monitoring wells in the Delaware River Basin and compares them to levels reported at the last DRBC commission meeting. Refer to Groundwater Notes at the end of this report for more details about the wells. Water levels within the 25- to 75- percentile range are defined as “normal”.

COUNTY

STATE

AGENCY
DATA

WELL ID

YEAR RECORD BEGINS

INDICATOR STATUS AS OF DECEMBER 7, 2015

CURRENT INDICATOR STATUS AS OF
MARCH 15, 2016

Sullivan

NY

USGS

Sv 535

2001

Normal

Normal

Wayne

PA

USGS

WN 64

1967

Normal

Normal

Monroe

PA

USGS

MO 190

1967

Drought Watch

Normal

Carbon

PA

USGS

CB 104

1969

Normal

Above Normal

Schuylkill

PA

USGS

SC 296

1975

Normal

Normal

Lehigh

PA

USGS

LE 644

1971

Normal

Normal

Berks

PA

USGS

BE 623

1975

Below Drought Emergency

Drought Watch

Lebanon

PA

USGS

LB 372

1973

Normal

Above Normal

Bucks

PA

USGS

BK 1020

1975

Normal

Above Normal

Chester

PA

USGS

CH 10

1966

Drought Watch

Normal

Delaware

PA

USGS

DE 723

1983

Drought Watch

Normal

Burlington

NJ

USGS

050689

1955

Below Normal

 
Below Normal

Cumberland

NJ

USGS

110042

1972

Normal

Normal

New Castle

DE

Delaware GS

Db24-18

1993

Normal

Normal

Chlorides (Salt Front)

The salt front is defined as the 250 parts-per-million isochlor. The seven-day average location of the salt front is used by DRBC as an indicator of salinity intrusion in the Delaware Estuary. The salt front’s location fluctuates along the main stem Delaware River as streamflow increases or decreases in response to changing inflows, diluting or concentrating chlorides in the river.

During February, the location of the seven-day average of the 250-ppm isochlor (salt front) ranged from river mile 73 at the start of the month to river mile 66 by month’s end. The normal location of the salt front during February is river mile 71, a location which is 7 miles downstream of the Delaware-Pennsylvania state line.

As of March 14 (the most recent date for available data), the salt front was estimated to be at river mile 68, which is two miles downstream of the normal location of the salt front during March.

 


 

Prepared by DRBC Staff.
Acknowledgments: Kimberly-Clark Corp.; National Weather Service; New York City Department of Environmental Protection; U.S. Army Corps of Engineers; U.S. Geological Survey; and Delaware Geological Survey.

Groundwater Notes:

  • Counties are ordered from North to South and East to West
  • Indicator status for PA wells is based on 30-day moving average of daily measurements and 30-day moving average statistics.
  • Indicator status for NY and NJ wells is based on a daily measurement and monthly-averaged statistics.
  • Indicator status for the DE well is based on a monthly, instantaneous measurement and monthly-averaged statistics.
  • The historical record for the NY well is too short to define a “normal” zone.  A graph of daily water levels is available on-line.
  • Records of groundwater levels (depth to water) at each well can be statistically analyzed to determine the percent of time that a given value is not exceeded. For example, the 25-percentile groundwater level is the level that is not exceeded 25 percent of the time in the existing record. Such percentiles are useful to compare to current groundwater levels; the three most commonly reported are the 25-, 50- and 75-percentiles (the 50-percentile is also called the median value). In this report we follow the customary practice of referring to the range of values defined by the 25- and 75-percentile as the “normal” range.
  • USGS uses the following definitions for water-level statistics: Normal (25- to 75- percentile flows); Drought Watch (10- to 25- percentile flows); Drought Warning (5- to 10- percentile flows); and Drought Emergency (0- to 5- percentile flows). Note: The categories labeled Drought Watch, Drought Warning, and Drought Emergency reflect only the relative range of the indicator values and are used for hydrological assessment purposes. Such category labels areindependent of official drought status which is declared only by the Governor of the respective state. Official declarations of drought stage are based upon a review of multiple ground and surface water conditions, soil moisture, precipitation, weather forecasts, purveyor reports, and other considerations.