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