| Abstract: | (mi2) in Pennsylvania and Delaware and includes
the major subbasins of Red Clay Creek, White Clay
Creek, Brandywine Creek, and Christina River. The Red
Clay Creek is the smallest of the subbasins and drains an
area of 54 mi2. Streams in the Christina River Basin are
used for recreation, drinking-water supply, and to
support aquatic life. Water quality in some parts of the
Christina River Basin is impaired and does not support
designated uses of the stream. A multi-agency, waterquality
management strategy included a modeling
component to evaluate the effects of point and nonpointsource
contributions of nutrients and suspended
sediment on stream water quality. To assist in nonpointsource
evaluation, four independent models, one for each
of the four main subbasins of the Christina River Basin,
were developed and calibrated using the model code
Hydrological Simulation Program?Fortran (HSPF).
Water-quality data for model calibration were collected
in each of the four main subbasins and in smaller
subbasins predominantly covered by one land use
following a nonpoint-source monitoring plan. Under
this plan, stormflow and base-flow samples were
collected during 1998 at 1 site in the Red Clay Creek
subbasin and at 10 sites elsewhere in the Christina
River Basin.
The HSPF model for the Red Clay Creek subbasin
simulates streamflow, suspended sediment, and the
nutrients, nitrogen and phosphorus. In addition, the
model simulates water temperature, dissolved oxygen,
biochemical oxygen demand, and plankton as secondary
objectives needed to support the sediment and nutrient
simulations. For the model, the basin was subdivided
into nine reaches draining areas that ranged from 1.7 to
10 mi2. One of the reaches contains a regulated reservoir.
Ten different pervious land uses and two impervious
land uses were selected for simulation. Land-use
areas were determined from 1995 land-use data. The
predominant land uses in the Red Clay Creek subbasin
are agricultural, forested, residential, and urban.
The hydrologic component of the model was run
at an hourly time step and calibrated using streamflow
data from three U.S. Geological Survey (USGS)
streamflow-measurement stations for the period of
October 1, 1994, through October 29, 1998. Daily
precipitation data from one National Oceanic and
Atmospheric Administration (NOAA) gage and hourly
data from one NOAA gage were used for model input.
The difference between observed and simulated stream-
flow volume ranged from -0.8 to 2.1 percent for the
4-year period at the three calibration sites. Annual
differences between observed and simulated streamflow
generally were greater than the overall error for the
4-year period. For example, at a site near Stanton, Del.,
near the bottom of the basin (drainage area of 50.2 mi2),
annual differences between observed and simulated
streamflow ranged from -5.8 to 6.0 percent and the
overall error for the 4-year period was -0.8 percent.
Calibration errors for 36 storm periods at the three
calibration sites for total volume, low-flow-recession
rate, 50-percent lowest flows, 10-percent highest flows,
and storm peaks were 20 percent or less. Much of the
error in simulating storm events on an hourly time step
can be attributed to uncertainty in the rainfall data.
The water-quality component of the model was
calibrated using nonpoint-source monitoring data
collected in 1998 at one USGS streamflowmeasurement
station and other water-quality
monitoring data collected at three USGS streamflowmeasurement
stations. The period of record for waterquality
monitoring was variable at the stations, with an
end date of October 1998 but the start date ranging
from October 1994 to January 1998. Because of
availability, monitoring data for suspended-solids
concentrations were used as surrogates for suspendedsediment
concentrations, although suspended solids
may underestimate suspended sediment and affect
apparent accur |
| Genre: | USGS Numbered Series |
| ProdID: | 53110 |
| Citation Author: | Senior, Lisa A.; Koerkle, Edward H. |
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| Citation Language: | ENGLISH |
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| Citation Phsyical Description: | x, 119 p. : ill., maps (some col.) ; 28 cm. |
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| Citation Series: | Water-Resources Investigations Report |
| Citation Series Code: | WRI |
| Citation Series Number: | 2003-4138 |
| Citation Search Results Text: | Simulation of streamflow and water quality in the Red Clay Creek subbasin of the Christina River Basin, Pennsylvania and Delaware, 1994-98; 2003; WRI; 2003-4138; Senior, Lisa A.; Koerkle, Edward H. |
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| Citation Year: | 2003 |
| Type: | citation/reference |
| Text: | Simulation of streamflow and water quality in the Red Clay Creek subbasin of the Christina River Basin, Pennsylvania and Delaware, 1994-98; 2003; WRI; 2003-4138; Senior, Lisa A.; Koerkle, Edward H. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/wri_2003_4138.jpg |
| URL (DOCUMENT): | http://pa.water.usgs.gov/reports/WRIR03-4138.pdf |
| Date Other: | Mon, 1 Dec 2003 00:00 -0600 |
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