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SEDIMENT BUDGETS
Agenda
• Terminology
• Sediment Budgets
–Location
–Literature and Data
–Sediment budget components
–Computational Methods
• Examples
Sediment Budget
What is a sediment budget?
• Sediment “check book”
–Debits – Credits = Balance
– Inputs – Outputs = dStorage
– (Sources) (sink)
Sediment Budget
Inputs - Outputs = D Storage
Soil erosion Runoff Deposition
Bank erosion Discharge Erosion
Mass wasting Wind Lake volume
Roads Sediment Yield Reservoir volume
Loess Channel size
Elevation
LOCATION
Sediment Budgets
Location
• Reservoir Studies
–Longevity, trapping efficiency
• Water Quality
–Sources, allocations, remediation
• Dredging
–Planning, storage, handling
• River Restoration
–Design, hydraulics, habitat
Dams
Dam Removal
River Restoration
LITERATURE & DATA REVIEW
Sediment Budgets
Data
• Historical surveys
–Utilities, DOT, USACE, bathy
–Old flood models
• Field samples
–Grabs, cores, probes
• Gage data – flow, TSS, etc.
–USGS, dams, NWS
• Others?
–Dendro, pollen, isotopic, chemistry
Construction Drawings
Historical Maps
Climatic Data
Geologic and Soils Data
Harbor or Navigation Surveys
What is TSS?
Total Suspended SOLIDS
= Sediment + Other Stuff
• Abiotic + Biotic
–Clastic, or mineral sediment
• Product of erosion
• Silt and Clay - typically
–Organic Matter (FPOM, VFPOM)
• Fish poo, leafy bits, tissue, etc
Sediment
Where does it matter?
• High Suspended load
• Trapping efficiency
–Particle density
–2.65 vs. ~1.1
• Nutrients
–Lake studies
Sediment
In practice…
• Ag land, mining, or other dominating sediment sources
–TSS > 50% mostly clastic
• Urban, Forest, Grassland, Wetlands, Lakes
–TSS has significant organic matter
• >50%
Sediment TMDL for TSS
Benchmark: Supply Limited
Impaired: Transport Limited
WARNING---Tangent: Hysteresis
10.1511.93
13.8313.88
15.7818.75
22.63
28.01
35.58
48.98
81.63
295.33
224.61
116.46
89.69
115.59
30
35
40
45
50
55
60
65
70
6/6/2001 16:48 6/6/2001 19:12 6/6/2001 21:36 6/7/2001 0:00
Time
Dis
char
ge
(l/s
)
17:2617:41
17:56
18:11
18:26
18:4118:56
19:11
19:2619:41
19:56
20:1120:2620:4120:56
y = 1.09e0.082x
R2 = 0.58
10
100
1000
30 35 40 45 50 55 60 65
Discharge (l/s)
To
tal
Su
spen
ded
So
lid
s (p
pm
)
COMPONENTS
Sediment Budgets
Sediment Budget Components
• Nonpoint source
–Soil/rill erosion
–Gully erosion
• Mass Wasting
• Channel / Bank Erosion
–Historic channel incision
• Reservoirs/lakes
–Shoreline, resuspension
COMPUTATIONAL METHODS
Sediment Budgets
Computational Methods
• Desktop
–Field data
–Published data
–Regional relationships
• Modeling
–Watershed
–River
–Reservoir/lake
Regional Sediment Yield
Know what to expect
Watershed Condition
• “Natural” background
• Elevated
• High
• Extreme
Typical Yield
• 0.01 - .1 t/ac/yr
• .1 – 1 t/ac/yr
• 1 – 10 t/ac/yr
• > 10 t/ac/yr
GIGO
Garbage In
=
Garbage Out
90m DEM 30m DEM 10m DEM
30m Grid
10m Grid
5m Grid
Roles of DEM resolution and computationl grid resolution on model accuracyCorrelation Coefficient between predicted and observed sediment yields from forest roads in the Southern
Appalachians
90m@3090m@10
30m@30
30m@10 30m@5
10m@10
10m@5
y = 0.10x0.17
R2 = 0.84
0.1
1.0
1 10 100 1000 10000 100000
DEM resolution (pixels/ha) x Grid resolution (pixels/ha)
r 2
0.2
0.3
0.4
0.5
0.6
0.7
0.8
EXAMPLES
Sediment Budgets
Battle Creek River Watershed
Soil Erosion
Channel Sediment
Sediment Yield Results
Source Sediment Yield
t/mi2/yr t/ac/yr t/ha/yr
U.S. Water Resources Council, 1968 10-800 .02 – 1.3 0.35
Leopold et al, 1995; Corbel, 1959 131 0.2 0.46
Brune, 1951 1514 2.4 5.30
Dendy and Bolton, 1976 685 1.1 2.40
Syed, Bennett, & Rachol, 2004 22 .03 0.08
Ouyang, Bartholic, & Selegean, 2005 25-49 .04 - .08 0.09–0.17
Past 516(e) studies 114 0.2 0.44
SWAT model 240 0.4 0.84
Baird
CLAYTOR EXAMPLE
Upstream Hydros
Current Sediment Yield
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
2007
2010
2013
2016
2019
2022
2025
2028
2031
2034
2037
2040
2043
2046
2049
2052
2055
Sto
rag
e V
olu
me (
10
00
s acre
-ft)
2001 Land Use
No BMPs
50% BMPs
80% BMPs
Forecasted Sedimentation
1710
1730
1750
1770
1790
1810
1830
1850
0 50 100 150 200 250
Storage Capacity (1,000's acft)
Ele
vati
on
(N
GV
D)
1964
2007
Current Land Use
Bare Soil
50% BMP Improvement
80% BMP Improvement
Storage volume impacts
Climatic Scenarios
0
50
100
150
200
250
300
90% 50% 10%
Wet Median Dry
Lo
ss o
f V
olu
me (
acre
-ft)
/year
Current Conditions
No BMPs
50% BMPs
80% BMPs
Reservoir Sedimentation
Case 50 Years: Average annual sedimentation
Zone 1
Zone 2
Zone 3
Zone 4
Baird
QUESTIONS
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