Transcript WRP-EnvEffectsofDams-StudentCopyx

Water Resources Planning
Instructors:
David
Rosenberg
and
Steve
Burian
Lesson Topic: Environmental Effects of Dams
Learning Objectives
 Quantify effects of dams on river channels
and indicator species
 Describe major approaches to mitigate
effects
 Determine effects of mitigation approaches
on key indicators
Environmental Effects of Dams
 Student suggestions…
Bed Degradation
What depth of
degradation is
possible…over how
long of a time period?
Sediment Trapping
• Facts: storage capacity in reservoirs is reduced each
year by sediment accumulation:
– Average of 0.2% annual reduction in U.S.
– Average of 0.5% annual reduction in Pacific states of U.S.
– Average of 2.3% annual reduction in China
• Activity:
– Work in pairs
– Use Internet or other source to find value of annual reservoir
capacity reduction from sediment trapping
– Use value you find (or an assumed reasonable value) and
calculate the time (in years) it will take to reduce reservoir
storage capacity to 75% of its original capacity
– Insert values into GoogleSheet (http://tinyurl.com/z78vok9)
Sediment Trapping - References
http://www.eolss.net/Sample-Chapters/C07/E2-12-02-05.pdf
Table 3.3 in: http://www.britishdams.org/reservoir_safety/defrareports/200102Sedimentation%20in%20storage%20reservoirs.pdf
Annandale, G. W. (2006). "Reservoir Sedimentation." Encyclopedia of
Hydrological Sciences, John Wiley & Sons, Ltd.
Crowder, B. M. (1987). "Economic costs of reservoir sedimentation: A
regional approach to estimating cropland erosion damage." Journal of
Soil and Water Conservation, 42(3), 194-197.
HDR. (2010). "South Fork Rivanna Reservoir Dredging Feasibility Study:
Dredging Alternatives Study." Rivanna Water and Sewer Authority,
Charlottesville, VA.
http://www.rivanna.org/documents/sfrrdredging/report_alternatives.pdf.
Hotchkiss, R. H., and Huang, X. (1994). "Reservoir sediment removal:
hydrosuction dredging." Hydraulic Engineering, 2, 1020-1024
Palmieri, A., Shah, F., and Dinar, A. (2001). "Economics of reservoir
sedimentation and sustainable management of dams." Journal of
Environmental Management, 61(2), 149-163.
What did the fish say when it ran into
the wall?
Blocking Fish Migration
Key Indicator Species
• Typically describe environmental impacts on key
indicator species (typically a fish!) – NEPA and
ESA driven
–
–
–
–
–
–
June sucker, Provo River, Utah
Azraq killfish, Azraq, Jordan
Bonneville cutthroat trout, Bear River
Delta smelt, Sacramento & San Joaquin Delta, CA
Coho and chinook salmon, Klamath River, CA
And many, many, many others
• Environmental management typically to mitigate
for species of concern – improve habitat
• Avoid focus on ecosystem function
Key Indicator Species
Salmon Spawning and Ocean Counts, CA
GHG Emissions
• Methane emitted from altered
biogeochemistry in reservoirs and
downstream waterways compared to freeflowing river
• Approximately equal to amount from global
aviation (4% of global emissions)
(internationalrivers.org)
Mitigation Approaches
• Operational
– Change timing and duration of releases
• Structural
– Multi-stage elevation releases
• Temperature control structures
• Thermal curtains
– Fish screens
– Fish ladders
• Management
– Environmental water accounts
• Remove dams (March 22)
Changing Reservoir Releases
Glen Canyon Dam, Colorado River (J. Schmidt)
Changing Reservoir Releases
(A) Pre- and (B) Post-Dam Sediment Fluxes
Dist.
below
Dam
(km)
Sediment
Reduction
(mmt)
Marble
Canyon
25
57 to 0.3
Upper
Grand
Canyon
170
83 to 14
Location
Changing Reservoir Releases
Significance of Fine-Sediment Deposits
• Distinctive attribute of the
pre-dam riverscape
• Campsites
• Creates stagnant flow and
backwater habitat at some
discharges
• Riparian ecosystem
substrate
• Deposits contain
archaeological resources
or stabilize those
resources
• Transport creates
turbidity
Changing Reservoir Releases
General Pattern of Sand Bar Change
(Badger Creek Rapids)
1956
Sand eroded
from eddies
Sand eroded by
wind; not
replaced by
flood
deposition
1999
Changing Reservoir Releases
Glen Canyon Dam Release Experiments
3000
DISCHARGE, IN CUBIC METERS PER SECOND
2500
2000
experiments
interim low
fluctuating flows
modified low
fluctuating flows
1996
Controlled
Flood
1500
maximum
powerplant
releases
1000
500
sediment conservation
0
1990
1992
1994
1996
1998
2000
1. Reduce range
of daily
fluctuations
(erosion
control)
2. Spiked “floods”
(rebuild high
elevation sand
bars)
3. Sustain low
flows (trap fine
sediment)
Changing Reservoir Releases
November 2004 Sediment Mobilization Flows
lost
hydropower
revenue ~
$1 million
Changing Reservoir Releases
Release Regime
Cost (lost hydro revenue)
[$ Millions]
Interim low fluctuating
flows (per year)
$36
Modified low fluctuating
flows (per year)
$44
Annual
revenue in
2003/2004
1996 controlled flood
$4
~ $140
million/yr
2003/2004 experimental
releases
Restoration budget
(FY 2004)
$2.85 (autumn)
$1.6 (winter)
$11.1
Changing Reservoir Releases
Glen Canyon Dam Postscript
Newly built sand bars were immediately eroded
by the large flow fluctuations, designed to
disadvantage spawning trout
Cutbank 1 day after
resumption of large
fluctuations
Temperature Controlled Release Tower
Shasta Dam, Sacramento River, CA
• 4.5 MAF storage
• Dam height 602 ft.
• Max. tower depth 350 ft.
Thermal Curtain
(Burgi, 1995; Vermeyan, 1995)
• Lewiston Lake,
Clear Creak,
California
Comparing Temperature Control Methods
(Burgi, 1995)
Fish Ladders
• Oroville Dam (right)
• John Day Dam
(bottom right)
• Bonneville (below)
Fish Ladders
Chinook (King) Salmon on the American River, CA
at the Nimbus Hatchery Fish Ladder
Fish Ladders
How Effective Are Fish Ladders?
Fish Ladders
Task: calculate percent passage across 1-8 fish
ladders (fishways) on the Columbia and Snake
Rivers (GoogleSheet: http://tinyurl.com/j7kawdg)
Fishway 6:
XX% passage
Fishway 7:
XX% passage
Fishway 5:
XX% passage
Fishway 2:
XX% passage
Fishway 1:
XX% passage
Fishway 3:
XX% passage
Fishway 4:
XX% passage
Fishway 8:
XX% passage
Fish Screens
Fish Screens
Fish Screens
Conclusions
• Can quantify environmental impacts of dams
and reservoirs with numerous indicators
• Site-specific factors determine type and
extent of impacts
• Regulation-imposed mitigation often required
• Structural, operational, and management
approaches to mitigate impacts
• Often pose significant costs
Learning Objectives
 Quantify effects of dams on river channels
and indicator species
 Describe major approaches to mitigate
effects
 Determine effects of mitigation approaches
on key indicators
References
Burgi, P.H. (1995). "The Evolving Role of Hydraulic Structures - From
Development to Management of Water." Issues and Directions in
Hydraulics - An Iowa Hydraulics Colloquium, Iowa City, Iowa,
http://www.usbr.gov/pmts/hydraulics_lab/history/transition/trans1.html.
Hollinshead, S.P., and Lund, J.R. (2006). "Optimization of environmental
water purchases with uncertainty." Water Resources Research, 42,
W08403, http://dx.doi.org/10.1029/2005WR004228.
Mostafa, M.G. (1957). "River-bed degradation below large capacity
reservoirs." American Society of Civil Engineers Transactions, 122, 688704.
Vermeyen, T.B. "Use of Temperature Control Curtains to Modify Reservoir
Release Temperatures." ASCE's First International Conference on
Water Resources Engineering, San Antonio, Texas,
http://www.usbr.gov/pmts/hydraulics_lab/tvermeyen/asce95m/index.html
Williams, G.P. and Wolman, M.G. (1984). "Downstream effects of dams on
alluvial rivers." Professional Paper 1286, U.S. Geological Survey,
Washington, D.C.