Remaining Capacity in GtLk R iGreat Lakes Reservoirs...US Army Corps Study Objectives of Engineers...
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US Army Corps of Engineers of Engineers Detroit District Remaining Capacity in G tLk R i Great Lakes Reservoirs
Transcript of Remaining Capacity in GtLk R iGreat Lakes Reservoirs...US Army Corps Study Objectives of Engineers...
US Army Corpsof Engineersof Engineers
Detroit District
Remaining Capacity in G t L k R iGreat Lakes Reservoirs
Storage Capacity Behind Great Lakes Dams –g yField Data and Modeling
• Motivation for project• Project overviewProject overview• Data and methods• Results from Lake Rockwell• Results from Lake Rockwell
US Army Corpsof EngineersDetroit District
Fluvial Sediment
Sand From Watershed = 880,000 cy/yr
200,000
250,000
1983
Channel Depth(ft)
16 18 2124 at entrance,21 in channel
1903 19541939
Total Average 37,500 53,000 35,00086,000 82,000
100,000
150,000
dge
volu
me
(cub
ic y
ards
)
Total maintenance
Entrance channel
Inner harbor
Entrance channeldredging trend
(cy/yr) ~1902 1903~1945 1992~Present1946~1970 1971~1991
0
50,000
1840 1860 1880 1900 1920 1940 1960 1980 2000 2020
Year
Dre
d g g
~20,000 cy/yr
Sediment Stored Behind DamsBerrien Springs Dam
US Army Corpsof EngineersDetroit District Berrien Springs Dam
Study ObjectivesUS Army Corpsof EngineersDetroit District
• Develop an understanding of the storage capacity for sedimentDevelop an understanding of the storage capacity for sediment behind dams in the Great Lakes through monitoring, modeling and assessment of historic documents.
• Understand and quantify the issues that influence the production and deposition of sediment in reservoirs
• How much storage capacity and time is left?
• Extrapolate this to remaining watersheds in Great Lakes
• Determine the sediment loading rate to the Great Lakesg
Dam Capacity Study TasksUS Army Corpsof EngineersDetroit District
Select 10 Reservoirs to studyThrough historical analysis/modeling determine: Through historical analysis/modeling determine: Present Sediment Erosion, Storage, and Delivery Pre-Settlement Sediment Erosion, Storage, and Delivery
Field data collection Sediment Cores Reservoir Bathymetry Reservoir Bathymetry
Sediment Rating Curves Storage Capacity Analysisg p y y Long-term simulation modeling Linear Regression modeling of sediment accumulation
R i S l iReservoir Selection
US Army Corpsof EngineersDetroit District
Reservoir Sedimentation
1 Continuous Sediment1. Continuous Sediment Trapping: Bedload and much of suspended load is trapped.
2. Partial Sediment Balance: Bed load is trapped, but fine sediments is removed in large flood eventslarge flood events. Submerged “floodplains” form.
3. Full Sediment Balance: Long-term equilibrium of both bedload and suspended load occurs.
From: Morris, Annandale, and Hotchkiss, 2008
Sedimentation rates using multipleSedimentation rates using multiple approaches:
– determination of the sedimentation rate of an impoundment by dating sediment cores using Cesium 137 (137Cs) and Lead 210 (210Pb).
– evaluation of sediment accumulation via analysis ofevaluation of sediment accumulation via analysis of historic bathymetric maps versus current bathymetric maps.USGS sediment gages– USGS sediment gages
– evaluation of sediment yield modeling.
Reservoir Selection Characteristics and Rank of Importance
R S lReservoir Selection
• 2,271 dams that were initially assessed• <50 impoundments contained all of the• <50 impoundments contained all of the
reservoir selection characteristicsTh 10 i l t d i• The 10 reservoirs are located in Indiana, Michigan, New York, Ohio, and Wi iWisconsin
• Represent a variety of watersheds types: urban, agriculture, forested…
F ld P dField Procedures
• The field procedures were designed so that work could be completed at eachwork could be completed at each impoundment in about three days– vibracore sediment samplingvibracore sediment sampling– a bathymetric survey
velocity transects of streams that feed each– velocity transects of streams that feed each impoundment
– surface water sampling (TSS testing)– surface water sampling (TSS testing)
WSU C P iWSU Core Processing
• Each 4-inch diameter core was frozen and sliced• top 10 centimeters of each core, 1-centimeter thick slices were selected
for dating; followed by 2-centimeter thick layers for datingg; y y g• Gamma Spectrometer
Sediment Accumulation Rates: 137 210137Cs and 210Pb
• Riley Dam, RD-6• 210Pb LinearPb Linear
Sedimentation Rate– 0.55 cm/yr
• 137Cs Peak Linear Sedimentation Rate– 0.57 cm/yr
• Application to a wide variety of projectsvariety of projects
Velocity Transects and Bathymetry
S k M9 S T k R SSontek M9 SonTek RiverSurveyor
• Acoustic Doppler Profiler (ADP) system designed to
i di hmeasure river discharge• 3-dimensional water
currents, depths, andcurrents, depths, and bathymetry.
• nine-beam system • two sets of four profiling
beams • one vertical beam• one vertical beam
Bathymetric Transects Green Lake, Wisconsin
Results from Lake Rockwell
•Bathymetric Surveys Historic and Present Day•Bathymetric Surveys – Historic and Present Day•USGS Sediment Gage Data•Corps of Engineers Great Lakes Regional•Corps of Engineers Great Lakes Regional
Sediment Data•Radionuclide Dating of Sediments•Radionuclide Dating of Sediments
Historic Contours
Sediment Yield Calculation
140
160
y
USGS 04202000
Qs = 0.126(Qw)0.739
R² = 0.666
60
80
100
120
140
ent L
oad
Ton
s/da
y
0
20
40
0 1,000 2,000 3,000
Sedi
me
Discharge cfsDischarge cfs
What do the sediments reveal regarding sediment accumulation rates?sediment accumulation rates?
Radionuclide Dating (Baskaran, et. al)
4 of 11 Sediment Cores Analyzed (2 partially complete at present)complete at present)
Sedimentation Accumulation Rate of Approximately 0.35 cm/year; 34.3 cmSedimentation Accumulation Rate of Approximately 0.35 cm/year; 34.3 cm accumulated since dam construction
Lake Rockwell and Region – Sediment Accumulation Comparisons
Method Sediment Load(Tons per year)
Bathymetric Data 17,980
Sediment Gages 19,300Sediment Gages 19,300“Dated” sediment accumulation rate
uniformly applied over reservoir 19,550
Sediment Regional Curves 20 500Sediment Regional Curves 20,500
Determination of Sediment Accumulation Great Lakes Sediment Yield CurveRates
Project Status
• Ongoing work (to be complete in 2014)– Sediment core dating g– Sediment SWAT modeling– Estimate the remaining storage capacity behind
dams– Capacity will be quantified in terms of time
remaining and volume remainingremaining and volume remaining
US Army Corpsof Engineers
Who Should Be Interested of Engineers
Detroit District in These Results?• Anyone doing dredging• Anyone building (or removing) a dam• Anyone building an impoundment (retention basin ice trap et c )• Anyone building an impoundment (retention basin, ice trap, et c.)• Anyone concerned about downstream impacts of sediment
o Fisheries managerso Flooding due to aggradationo Flooding due to aggradationo Water treatment plantso Power companieso And many others!y
We have created a landscape that is shedding sediment at an artificially high rate. The downstream delivery of this sediment is being temporarily arrested by the 2581 dams in Michigan……but for how long?
US Army Corpsof Engineersof Engineers
Detroit District Questions?
Contact:Dr. Jim Selegean, P.E., P.H.
U S A C f E i D t it Di t i tU.S. Army Corps of Engineers, Detroit DistrictGreat Lakes Hydraulics and Hydrology Office
477 Michigan AveDetroit, MI 48226
313.226.6791
