A Study of Forest Influence
on Streamflow in the Pequannock Watershed of Northern New
||To determine the effects of forest management practices on
water quality and quantity.
||The 3 watersheds are located near Newfoundland, NJ. (41 deg
01 min 30 sec N.Lat. and 74 deg 26 min 30 sec W.Long) within
the 36,000-acre Pequannock drainage, owned by the City of Newark.
The drainage supplies about 1/2 of the water supply of Newark
and adjacent cities. The watersheds have a southeast aspect
and lie between 900 and 1,200 feet in elevation. Slopes are
gentle near the stream-gaging stations, but steeper near the
ridge of Copperas Mountain. Watershed 1 is 68 acres, watershed
2 is 42 acres, and watershed 3 is 23 acres in area. All watersheds
had intermittent summer flow during the drought period years
Forest type is oak-hickory and soils range from very poorly
drained and swampy to well drained and very stony to bouldery.
Soils are usually less than 24" deep and much of the surface
is covered with stones or boulders, especially on the upper
portions of the watersheds. Rock outcrops are common. Mid-slope
soils are deeper and are moderately well to poorly drained.
Site quality is generally low. Repeated cuttings for charcoal
and a series of wildfires have reduced the forest quality to
a level probably lower than the site would normally support.
||Paired watershed analysis; single watershed calibration
|Likelihood of Locating Study Areas:
||Watershed 1: all trees 1" diameter at ground surface and larger
within a zone 20' on each side of the storm channel were injected
with ANSAR 160 herbicide in May 1965. Remaining vegetation was
sprayed with Weedone herbicide using a portable mistblower.
Vegetation was cut and removed, or deadened by herbicide within
a strip 20' wide on each side of the feeder stems to remove
vegetation that dropped its leaves into the stream. All trees
were felled by 1967 spring and a vigorous ground cover had developed.
1967: trees 5' above the stream channel were injected with herbicide.
This widened the treatment area to approximately 40' on each
side of the channel. After 1968 growing season, all trees in
the expanded treatment zone were felled and the slash was burned.
Watershed 2: Control - no herbicide, no cuttings. July 1971
75% overstory defoliated by gypsy moth.
Watershed 3: all trees >1" diameter ground surface were injected
with herbicide Fall 1965 and Weedone was applied using a mistblower
on several areas of dense undergrowth. By summer 1966 live
overstory vegetation had been reduced to 31% of the watershed
area. Aerial application of herbicide was made using a helicopter
June 1967. By summer 1967 live overstory had been reduced
to 3% of 1965 stocking. Ground cover continued to increase
and covered 41% of the watershed.
Injection of herbicide: Fall 1965
Aerial application of herbicides: June 1967.
||2 methods to estimate gypsy moth effects. 1) equation was
developed to predict s streamflow from a measured watershed.
2) regression equations were developed to predict streamflow
from precipitation parameters.
|Variables and Sampling Frequency:
||streamflow (CFS,CSM, inches)
air temperatures ( degrees F)
relative humidity (%)
precipitation amount (inches) & intensity
streamwater temperature (degrees F): 1959-1972, instrument charts
||Observer and instruments checked periodically. Compilation
of climatic data were spot checked. Control water samples were
taken before, during, and after herbicide spraying.
||Summarized by Fortran program and analyzed by hand. Streamflow
readings on computer tape, data charts, are stored in 3 file
cabinet drawers. Other data hardcopy only.
|Global Change Research Applications:
||Studies of Ecosystem Processes
|Publications and Reports:
||Corbett, E.S.; Heilman, J.M. 1975. Effects of management practices
on water quality and quantity: The Newark, New Jersey, municipal
watershed. In: Proceedings, Municipal watersheds management
symposium; 1973 September 11-12; University Park, PA. Gen. Tech.
Rep. NE-13. Upper Darby, PA: U.S. Department of Agriculture,
Forest Service, Northeastern Forest Experiment Station. 47-57.
E.S. Corbett; Sopper, W.E.; Lynch, J.A. 1975. Municipal watershed
management: what are the opportunities? In: Proceedings, Forestry
issues in urban America. 1974 September 22-26; New York, NY;
New York, NY: Soc. Am. For. Nat. Conv. 50-57.
||Richard Birdsey, USDA Forest Service, 11 Campus Boulevard,
Suite 200, Newtown Square, PA 19073. (610) 557-4091.
||Division of Water Supply, Department of Public Works, City
of Newark Division of Parks and Forestry, Department of Conservation
and Economic Development, State of New Jersey.