ecosystems climate and land-use change water natural hazards core science systems energy and...
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Ecosystems
Climate and Land-Use Change
Water
Natural Hazards
Core Science Systems
Energy and Minerals, and Environmental Health
U.S. Geological Survey Mission Areas
Investigation of Suspended Sediment Concentrations in Jackson Creek Before and During Construction
Activities: Presentation to the Carys Lake Home
Owner’s Association
January 14, 2014Celeste Journey, Water-Quality Specialist
U.S. Geological SurveySouth Carolina Water Science Center
Columbia, SC
Concern• Contacted by Alicia De Myher• Referred by my Water Science Center director, Eric Strom• Requested USGS input
• Concern of the Carys Lake Home Owner’s Association is the proposed construction of a new school in Jackson Creek watershed. • Proposed site located immediately upstream of Carys Lake• Proposed site drains to Little Jackson and Jackson Creeks• Past school construction activities resulted in increased sediment
deposition in Carys Lake.• Uncertain that appropriate BMPs will be used to prevent a
recurrence of the sediment issue in Carys Lake.
Proposed Construction Site
Requested Input• Evaluation of what would be the best erosion prevention and
sediment control Best Management Practices (BMP)• Regulated by South Carolina Department of Health and
Environmental Control (SCDHEC)• Options provided in the Storm Water Management BMP Field
Manual• https://www.scdhec.gov/environment/ocrm/docs/Field_Manual/
OCRM_DHEC_FIELD_MANUAL.pdf.
• Outside of U.S. Geological Survey mission • Evaluation of how effective any implemented BMPs were at
reducing or preventing sediment erosion• Monitoring of sediment• Within the U.S. Geological Survey mission
USGS Mission Areas• Understanding ecosystems and predicting ecosystem change—this
science direction is designed to … monitor “biological and physical components . . . of ecosystems.”
• A water census for the United States—to, among other things, provide information and forecasts “of likely outcomes for water availability, water quality and aquatic ecosystem health caused by changes in land use and land cover . . .[and] natural and engineered infrastructure.”
• The U.S. Geological Survey South Carolina Water Science Center has had a presence in Gills Creek watershed since 1995• Surface-water monitoring of stream for nutrients, pesticides,
suspended sediment, and aquatic biota for over 15 years• Streamflow monitoring• USGS Station 02169570
Proposed Construction Site
Windsor Lake
Proposed
Constructi
on
Site
Carys
Lake
Potential Approaches• Bathymetric surveys of Carys Lake• Pre-construction• Post-construction• PROs: quantifies impact to Carys Lake• CONs: “damage” is already done
• Continuous turbidity monitors• Installed prior to construction to obtain baseline conditions• Provides real-time information to determine if suspended sediment
concentrations have increased• PROs: can set up “thresholds” that provide real-time warnings of
increases in suspended sediment concentrations• CONs: expensive
• Suspended sediment sampling and streamflow measurements in Jackson Creek• PROs: Provide scientifically defensible data to determine if suspended
sediment concentrations have increased• CONs: Not as “real-time” as turbidity monitors
Potential Approaches• Two possible suspended sediment monitoring approaches• Before and During• ~ 3 ½ years • Data collection 1 year before and 1 year during construction at
one site• 1 year of data analysis and report writing
• Upstream and Downstream• ~ 2 years• 1 year of data collection at two sites (upstream/downstream)
during construction• 1 year of data analysis and report writing
• Same cost• Timeline changes
Potential Approaches• Two possible suspended sediment monitoring approaches• Before and During• ~ 3 ½ years • Data collection 1 year before and 1 year during construction at
one site• 1 year of data analysis and report writing
• Upstream and Downstream• ~ 2 years• 1 year of data collection at two sites (upstream/downstream)
during construction• 1 year of data analysis and report writing
• Same cost• Timeline changes
Windsor Lake
Proposed Construction Site
Possible sampling location
Carys Lake
Proposed Approach• BEFORE construction activities begin (Baseline Conditions)• Streamflow measured at the time of sampling• 10 samples are collected as depth- and width-integrated samples,
not a grab• Samples are analyzed for Total Suspended Solids (aka TSS) and
Suspended Sediment Concentrations• 50% of the samples target runoff conditions
• DURING construction activities (Impacted Conditions)• Streamflow measured at the time of sampling• 10 samples are collected as depth- and width-integrated samples,
not a grab• Samples are analyzed for Total Suspended Solids (aka TSS) and
Suspended Sediment Concentrations• 50% of the samples target runoff conditions
Depth- and Width-Integrated vs. Grab Samples
1 2 3 4 5 6 7 8 9 10
O N D J F M A M J J A S O N D J F M A M J J A S
Site reconnaissance and selection X
Suspended Sediment Sampling
Pre-construction X X X X X X X X X X X XPost-construction
Data Analysis X X X X
Open-File Report Writing
O N D J F M A M J J A S O N D J F M A M J J A S
Site reconnaissance and selection
Suspended Sediment Sampling
Pre-constructionPost-construction X X X X X X X X X X X X
Data Analysis X X X X
Open-File Report Writing X X X X X X X X X X X
Task
Task
Fiscal Year 2014 Fiscal Year 2015
Fiscal Year 2016 Fiscal Year 2017
Products• End of the year summary and data analysis• Baseline conditions in Jackson Creek• Construction-impacted conditions in Jackson Creek• Statistical comparison of the two conditions
• U.S. Geological Survey Open-File Report• Publically accessible on website: http://water.usgs.gov/pubs• Electronic datasets
Funding
FY 2014 FY 2015 FY 2016 FY 2017Overall
Cost
$17,000 $27,000 $33,000 $38,000 $115,000
