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Most Recent Hydrologic Conditions Report
June 14, 2016
Precipitation

The observed precipitation for the Delaware River Basin above Montague, New Jersey for the period January 1, 2016 through June 13, 2016 was 15.50 inches, or 3.63 inches below normal. For the period January 1, 2016 through June 13, 2016, the observed precipitation for the Delaware River Basin above Trenton, New Jersey was 16.70 inches, or 3.38 inches below normal for this period. Also through June 13, the observed precipitation for Wilmington, Delaware was 19.12 inches, or 0.38 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 May 2016 was 5,065 cubic feet per second (cfs), or 88-percent of the long-term average for the month. The average observed streamflow of the Delaware River at Trenton, New Jersey in May 2016 was 9,492 cfs, or 81-percent of the long-term average for the month.

During June 1-13, the average observed streamflow of the Delaware River at Montague was 3,080 cfs, or 97-percent of the long-term average for the month. Similarly, the average streamflow at Trenton was 6,942 cfs, or 97-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 June 13, 2016.

Reservoirs

Lower Basin

Lower Basin Reservoir Storage as of June 14, 2016:
Beltzville

13.52 billion gallons (bg) usable, or 100% of usable storage

Blue Marsh

5.83 bg usable, or 101% of summer pool usable storage

Merrill Creek

14.1 bg usable, or 90% of usable storage

Upper Basin

New York City (NYC) Delaware Basin Reservoir Storage as of June 14, 2016:
Pepacton

135.8 bg usable, or 97.0% of usable storage

Cannonsville

90.3 bg usable, or 94.4% of usable storage

Neversink

34 bg usable, or 97.3% of usable storage

Total

260.1 bg usable, or 96.0% of usable storage

The long-term median storage for the NYC Delaware basin reservoirs for June 14 is 263.9 bg, or 97.4% 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 (June 14, 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 MARCH 15, 2016

CURRENT INDICATOR STATUS AS OF
JUNE 14, 2016

Sullivan

NY

USGS

Sv 535

2001

Normal

Normal

Wayne

PA

USGS

WN 64

1967

Normal

Drought Watch

Monroe

PA

USGS

MO 190

1967

Normal

Drought Watch

Carbon

PA

USGS

CB 104

1969

Above Normal

Normal

Schuylkill

PA

USGS

SC 296

1975

Normal

Drought Watch

Lehigh

PA

USGS

LE 644

1971

Normal

Drought Watch

Berks

PA

USGS

BE 623

1975

Drought Watch

Below Drought Emergency

Lebanon

PA

USGS

LB 372

1973

Above Normal

Normal

Bucks

PA

USGS

BK 1020

1975

Above Normal

Normal

Chester

PA

USGS

CH 10

1966

Normal

Normal

Delaware

PA

USGS

DE 723

1983

Normal

Drought Watch

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 May, the location of the seven-day average of the 250-ppm isochlor (salt front) ranged from river mile 69 to river mile 71. The normal location of the salt front during May is river mile 68, a location which is 10 miles downstream of the Delaware-Pennsylvania state line.

As of June 13 (the most recent date for available data), the salt front was estimated to be at river mile 71, which is two miles upstream of the normal location of the salt front during June.

 


 

Report prepared by DRBC Staff.

Acknowledgments: Kimberly-Clark Corp.; NWS; NYC DEP; USACOE; USGS; Delaware Geological Survey (DGS).

NOTES:

  1. The groundwater 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. Drought Watch represents values in the 10-25 percentile depth, Drought Warning represents values in the 5-10 percentile depth, and Drought Emergency represents values in the 0-5 percentile depth. Such category labels are independent 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.
  2. Counties are ordered from North to South and East to West.
  3. Indicator status for PA wells is based on USGS 30-day moving average of daily measurements and 30-day moving average statistics.
  4. Indicator status for the NY and NJ wells is based on USGS daily measurements and monthly-averaged statistics.
  5. The indicator status for the DE well is based on Delaware Geological Survey (DGS) instantaneous measurements and monthly-averaged statistics, as available. The Average, 75-percentile, and 25-percentile curves used to determine status were calculated by DRBC staff using the period of record up to December 2000.
  6. 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.