An Examination of Winyah Bay,South Carolina
Under Two Different Flow Conditions
Kathryn Benson
CE 394K GIS in Water Resources
University of Texas at Austin
Fall 2002
OBJECTIVE
To examine the mixing
characteristics of Winyah
Bay, South Carolina under
two different streamflow
conditions
Where to start?
•Data Acquisition from the
University of South Carolina
• EPA River Reach File-Region 03
•USGS Hydrologic Cataloging Unit
Watershed Characteristics
Second largest watershed on
the Atlantic Coast
UPPER YADKIN
SOUTH YADKIN
LOWER YADKIN
3 States
12 HUCS
ROCKYUPPER PEE DEE
LUMBER
LOWER PEE DEELITTLE PEE DEE
WACCAMAW
LYNCHES
CAROLINA COASTAL-SAMPIT
BLACK
Pee Dee
Streamflow
Conditions
Five Main Rivers
flow into
Winyah Bay
Little PD
Define streamflow
for two days of
sampling
Lynches
High vs. average
flow conditions
due to snowmelt
Use of Time Series
Function
Black
Waccamaw
Average Daily Streamflow
12000
17-Apr-99
12-Feb-00
10000
Streamflow (cfs)
8000
6000
4000
2000
0
Black River
Pee Dee River
Little Pee Dee River
Waccamaw River
Average Streamflow, April 17, 1999
Average Streamflow, February 12, 2000
River
Black River
Pee Dee River
Lower Pee Dee River
Wacacmaw River
Lynches River
River
Black River
Pee Dee River
Little Pee Dee River
Wacacmaw River
Lynches River
Daily Total Flow (cfs)
6110.57
Flow (cfs)
338.5
2124.69
1775.42
1390.42
481.54
Daily Average Flow (cfs)
1222.11
Total Flow (cfs)
25165.41
Flow (cfs)
1807.08
10529.17
6944.58
3912.08
1972.5
Average Flow (cfs)
5033.08
Lynches River
WB200.5WB499.14
WINYAH BAY, SC
68.3 km2 or 26.3 mi2
WB200.6WB499.13
Six sampling sites per day for
ebbing tide (freshwater towards
ocean)
 Interface between freshwater
and saltwater is extended over
approximately a 10 km area from
the rivers to the mouth of Winyah
Bay (Zabawa, 1979)
WB499.10
WB200.7
WB499.9
WB200.14
WB499.7
Mixing point for low flow is
WB499.9
Partially Mixed Estuary
Mixing point for high flow is
WB200.13
WB200.11
River Dominated Estuary
WB499.4
WB200.13
Salinity Profiles During an Ebbing Tide from the Rivers to the Mouth
Salinity (psu)
WB499.14
0
5
10
15
20
25
30
35
40
0
1
WB499.13
2
3
Depth (m)
WB499.14
WB499.10
WB499.9
4
WB499.13
WB499.9
5
6
WB499.10
WB499.7
WB499.4
WB499.7
7
8
WB499.4
9
10
WB200.5
WB200.6
WB200.7
WB200.14
WB200.13
WB200.11
CTD
What else does streamflow
effect?
NISKIN
Chemical Processes
Nutrient Concentrations
Suspended Material
Non-point Source Pollution
Point Source Pollution
Higher Nutrient
concentration
Total Suspended Matter (TSM), April 17, 1999
350
Higher
concentration of
TSM with higher
streamflow
TSM (mg/l) Surface
300
TSM (mg/l) Bottom
TSM (mg/L)
250
200
150
100
50
0
0
1
2
3
4
Sample Sites
5
6
7
USGS website- HUCs, NHD, State geography and waterbodies, gaging station and NWIS data
(http://www.usgs.gov)
EPA website-surf your watershed, river reach file (http://www.epa.gov)
South Carolina Department of Natural Resources-orthophotos (http://dnr.state.sc.us)
ESRI-data library and help function
Correll, D.L., 1998. The Role of phosphorus in the eutrophication of receiving waters: A review. Journal of
Environmental Quality 27:(2). Pp. 261-266.
Falhowski, P.G. and J.A. Raven, 1997. Aquatic Photosynthesis. Blackwell Science, Lt. 2. pp. 310-311.
Horton, H.R., L.A. Moron, R.S. Ocha, J.D. Rown, and K.G. Scriagaer, 1996. Principles of Biochemistry: 2nd edition.
Prentice-Hall, Inc. pp. 498-499.
Troup, B. N. and Bricker, O. P, 1975. Processes Affecting the Transport of Materials from the Continents to Oceans.
Marine Geochemistry in the Coastal Environment: American Chemical Society.
Zabawa, Christopher F., 1979. Estuarine Sediments and Sedimentary Processes in Winyah Bay, South Carolina. South
Carolina Geological Society: Geologic Notes 23;(2). Pp. 79-117.