Download Interannual Trends in the USGS Coastal Gaging Network Data

Interannual Trends in the USGS
Coastal Gaging Network Data
Paul Conrads USGS – SC Water Science Center
Waccamaw Water Quality Data Conference
September 29, 2010
Litchfield Beach, SC
U.S. Department of the Interior
U.S. Geological Survey
What’s on tap……..
General remark on gaging networks
A short history of Grand Strand gaging
network
A look at some Waccamaw data
How does the Waccamaw compare?
Update on Climate Change/Salinity Intrusion
Study
Gaging Network Data Uses
Resource appraisal and allocation
Design of water infrastructure
Flood hazard planning and forecasting
Reservoir operations
Water quality management
Instream flows for habitat assessment
Understanding changes of streamflow
Recreational safety
Guiding Principles of the
Streamgaging Network
Many partners contribute funding
All data are freely available
USGS operates the network on behalf of all
Reality – network meets many needs but funded
by a few
Grand Strand Network – funded by WRCOG,
USGS, Horry County, GSWSA, GCWSD, and
Myrtle Beach
Grand Strand Network Active and
Discontinued Continuous Monitors
Grand Strand Network
Short history
Pee Dee River basin
flow monitoring – > 60
years at 7 stations
Grand Strand Network
(Water quality, water
level, and flow) begun
in 1983
Pee Dee River
basin flow
stations
Grand Stand
Network
stations
Grand Strand Water Resource Issues
Role of the USGS network – 1980’s
Mid 1980s – freshwater potential of AIW
Groundwater issues
Large cone of depression
Taste and odor issues
Network data used for the analysis the suitability
of the AIW for water supply
Real-time salinity alert system
Late 1980s
Initial data collection for flow and water-quality
model
Grand Strand Water Resource Issues
Role of the USGS network – 1990’s
Early 1990s
Economic growth – expanding wastewater
demand
Assimilative capacity of AIW and Waccamaw
River
Network data used to support model and analysis
DO TMDL - 1999
Grand Strand Water Resource Issues
Role of the USGS network – 1990’s
Hurricane Floyd - 1999
Flood of record on Waccamaw River
Gaging network critical for:
▪ Emergency preparedness
▪ River forecasting
▪ Storm surge monitoring
How high to sandbag?
Data used by NOAA to improve storm surge
models along Grand Strand
Grand Strand Water Resource Issues
Role of the USGS network – 2000’s
Non-point Source 319 Study – Libes
Connection between storm water loading and effects in the
AIW
Decade of Drought
Summer of 2002
Pee Dee River at historic lows
Network data and model used to determine minimum
flow
FERC Re-licensing of NC reservoir - 2006
Data critical in demonstrating effect of releases on
salinity intrusion along Grand Strand
Developed Salinity Intrusion Decision Support System
for analyzing river flows, tidal conditions, and salinity
intrusion
Grand Strand Water Resource Issues
Role of the USGS network – 2010
Death of Stationarity
Non-point source loading
Increased urbanization
Altered surface and groundwater interaction
Increased regulation of storm water
Climate Change
Far reaching effects on many sectors of society
Water resources
Transportation
Ecosystems
Energy supply and use
Agriculture
Human Health
“…estuaries may never really be
steady-state systems; they may be
trying to reach a balance they
never achieve.”
Keith Dyer, from Estuaries – A Physical Introduction (1997)
Riverine
Inputs
Freshwater
Coastal
Inputs
Saltwater
Saltwater-Freshwater
Interface
Stationarity?
Flow and Specific Conductance
Flows - living between extremes
Duration hydrograph: Waccamaw River at Longs
Grand Strand Network
DO and Temperature
Do Deficit
Compute DO deficit to “normalize” DO signal
to temperature
DO deficit = difference between DO at saturation
and measured DO
The higher the DO deficit, the lower the water
quality
Generate frequency distribution curves to
compare between sites and time periods
DO Deficit at Conway
DO Deficit at Conway
How Does Conway Compare?
Breakpoint Analysis
Find breaks in time-series data
Z-score
(value – mean)/standard deviation
“score” of how values relates to distribution of data
Cumulative Z-score
Sum of consecutive z-scores
Plot cumulative z-scores
Changes in slope > change in dynamic behavior
Everglades Example
Grand Strand
How Does Conway Compare?
1998
2002
2007
2010
How Does the Grand Strand Compare?
Time series
Missing
data
How Does the Grand Strand Compare?
Frequency distribution
Global Climate Change Impacts in the United States
State of Knowledge Report (USGCRP, 2009)
Average temperatures rise between
4.5° and 9°F by 2080
Higher sea-surface temperature
Lower dissolved oxygen
Higher evapotranspiration
Higher intensity hurricane storms –
precipitation, wind speed, storm
surge
Sea level rise – increase salinity
intrusion, loss of wetlands and
barrier islands
Aquatic stress due to increase
temperatures and decreases in DO
Increases in drought and increases
in high intensity rain events
Sea-Level Rise
From: Furlow and others, 2002
South Carolina Intakes in Coastal Waters
Myrtle Beach
Grand Strand
Georgetown
Charleston
Beaufort
Savannah
Existing Salinity Intrusion Models
Pee Dee and Waccamaw
Rivers and Atlantic
Intracoastal Waterway
Myrtle
Beach
Georgetown
Charleston
Beaufort
Savannah
Lower Savannah
River Estuary
EIS Savannah
Harbor Deepening
FERC Re-licensing
NC lakes
Climate Change Studies – Grand Strand
USC – NOAA grant ($375k) -- simulate flows in the
Pee Dee River due to changing precipitation patterns
USGS/ADMi Water Research Foundation grant ($100k
- BJSWA sponsor) – input changing streamflow
conditions to analysis effect on salinity intrusion in
the Waccamaw River and AIW
Network data and salinity intrusion ANN models
critical elements of both studies
Conceptual Climate Change Model
Salinity Intrusion
Global & regional
circulation models
(USC-Carbone)
Gridded rainfall
input to watershed
model (USCTufford)
Salinity intrusion
model – PRISM
(USGS &ADMi)
Precipitation
Temperature
Watershed model
Fl
ow
>
SM
I
PR <Sea-level rise
Preliminary Results – Retrained Models
Grand Strand – Pawleys Island Gage
14 year SLR simulation
0.2 to 2-ft SLR
Frequency intake is unavailable quadruples with 2-ft
rise
Scenario-SLR
0.0
0.2
0.5
1.0
1.5
2.0
Days SC>2,000 uS/cm
174
201
279
404
559
702
% of Days
4.7%
5.5%
7.6%
11.0%
15.2%
19.1%
Summary:
Grand Strand Network
Provided the Region with valuable water
resource information for 25 years
Freshwater potential
Assimilative capacity - TMDL
Storm surge and hurricane model improvements NOAA
Non-point source evaluation – 319 Study
Salinity Intrusion Study – FERC relicensing,
current climate change studies
Future issues
Discussion
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