D A M R E M O V A L

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D A M R E M O V A L
Panacea or Pandora for Rivers
Joseph C. Greene Research Biologist Greene
Environmental Services May 2006
Original background illustration from Gregory
Stewart, Ph.D. http//www.collbett.org/greg/
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Some Facts

• Hydropower is the most plentiful and efficient
  renewable energy resource. It contributes more
  than 90 percent of all renewable electric energy
  produced in the U.S.
• If all the energy produced by hydropower was
  produced by coal instead, pollutants from coal
  would increase by 16 percent
• A third of countries depend on hydropower for
  over half their electricity, and over a third of
  irrigated land depends on dams and,
• much of the world's food is subsidized by cheap
  irrigation water provided by dams.

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The Argument Against Dams
The reservoir or lake created by a dam may cover
many thousands of acres of forest that once
served as habitat for wild animals and plants.
Large dams have contributed to

• the extinction of many fish and other aquatic
  species
• the disappearance of birds in floodplains
• huge losses of forest, wetland, and farmland
  and,
• the erosion of coastal deltas.

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Dam Removal
Panacea or Pandora for Rivers
The debate is playing out against a backdrop of
power crises, cycles of flood and drought,
endangered ecosystems, and changing societal
expectations and demands for water.
The idea that dams are not necessarily permanent
features of the landscape, but can and should be
removed, has emerged as a rallying cry, political
lightning rod, and unparalleled scientific
opportunity for understanding the behavior of
rivers
Grant, G., 2001, Dam Removal Panacea or Pandora
for Rivers?, Hydrological Processes 15, 1531-152.
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Why is dam removalemerging as an issue?

• Increased hazard of aging dams
• Open policy window because of the large number
  up for re-licensing
• Response to concerns about physical
  fragmentation of river systems

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Why is dam removal emerging as an issue?

• Response to concerns about threatened and
  endangered fish species
• Response to calls for the return to a more
  natural hydrologic regime to restore ecological
  and geomorphic (surface configuration ) function
  and,
• Finally, dam removal has great symbolic value
  in terms of representing our good intentions
  toward our environment.

Grant, G., 2001, Dam Removal Panacea or Pandora
for Rivers?, Hydrological Processes 15, 1531-152.
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Dam Removal
A striking conclusion from a number of recent
workshops was
We actually know very little about the
biological and physical consequences of removing
dams.
Grant, G., 2001, Dam Removal Panacea or Pandora
for Rivers?, Hydrological Processes 15, 1531-152.
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The response to dam removal is intrinsically
complex!
Because of the longevity of dams, channels
typically adjust to the altered hydrologic and
sediment transport regimes that dams impose
consequently,
Dam removal itself represents a land surface
re-configuration disturbance to a quasi-adjusted
river system.
Grant, G., 2001, Dam Removal Panacea or Pandora
for Rivers?, Hydrological Processes 15, 1531-152.
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We know that this disturbance tends to propagate
both upstream and downstream through cascades of
erosional and depositional processes that are
coupled in time and space.
Typically, the upstream response drives the
downstream response.
Grant, G., 2001, Dam Removal Panacea or Pandora
for Rivers?, Hydrological Processes 15, 1531-152.
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Stewart, G, S. Hayes, G. Grant, and C. Bromley,
2003, Where did all the dam sediment go,
Predicting the effects of dam removal on channel
morphology and ecology.
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From Gregory Stewart, Ph.D.
http//www.collbett.org/greg/
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From Gregory Stewart, Ph.D. http//www.collbett
.org/greg/
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From Gregory Stewart, Ph.D. http//www.collbett.
org/greg/
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From Gregory Stewart, Ph.D. http//www.collbett.
org/greg/
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From Gregory Stewart, Ph.D.
http//www.collbett.org/greg/
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Key upstream unknowns are
The rate and mechanisms of removal of sediment
from the upstream reservoir in relation to ..

• Flow regime
• Grain size
• Channel and deposit geometry
• Method of dam removal.

Grant, G., 2001, Dam Removal Panacea or Pandora
for Rivers?, Hydrological Processes 15, 1531-152.
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Downstream of the Dam
Sediment will be transported through a channel
system already altered by the presence of the dam.
A complex array of storage features and
associated residence times limits our ability to
accurately predict how long it will take for
sediment to be routed downstream.
Grant, G., 2001, Dam Removal Panacea or Pandora
for Rivers?, Hydrological Processes 15, 1531-152.
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Downstream of the Dam
Even more challenging to predict are the
interactions among

• Sediment transport and deposition
• Vegetation establishment
• Responses to aquatic ecosystems to elevated
  sediment loads and,
• Transformed channel morphology.

Grant, G., 2001, Dam Removal Panacea or Pandora
for Rivers?, Hydrological Processes 15, 1531-152.
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Needs
We need coordinated retrospective laboratory and
field studies .

• On how dams function in the landscape
• On impacts and consequences of past removals,
  including analysis of dam removal analogues, such
  as natural and artificial dam failures and,
• Studies that are rigorous pre- and post-removal
  monitoring schemes for those dams slated for
  removal.

The studies should be targeted at resolving key
uncertainties.
Grant, G., 2001, Dam Removal Panacea or Pandora
for Rivers?, Hydrological Processes 15, 1531-152.
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From Past Work on the Effects of Dams on Rivers
We know that all dams are not created equal!
Grant, G., 2001, Dam Removal Panacea or Pandora
for Rivers?, Hydrological Processes 15, 1531-152.
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The Same May Be True For Dam Removal

• Some will stimulate dramatic effects on river
  and ecosystem processes
• Others will have no effects
• Some may open Pandoras boxes of new problems.

Grant, G., 2001, Dam Removal Panacea or Pandora
for Rivers?, Hydrological Processes 15, 1531-152.
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The National Academies' National Research Council
committee estimated that the research,
monitoring, and remediation outlined in its
report, on the Klamath River Basin, would cost
about 25 million to 35 million over the next
five years .
excluding costs for major projects SUCH AS DAM
REMOVAL!
National Research Council, 2003, News Release,
Broader Approach Needed for Protection And
Recovery of Fish in Klamath River Basin,
http//national-academies.org
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Savage Rapids Dam Rogue River, Oregon
The design for the removal of Savage Rapids dam
is proceeding, slowly.  The completion date isn't
moving up, but the cost sure is. 
The Bureau of Reclamation estimates a cost of 30
million to remove part of Savage Rapids Dam and
install pumps
Grants Pass Daily Courier, "Savage Rapids Total
30 Million."
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Klamath River Dam Removal Investigation

• J. C. Boyle Dam
• Copco 1 Dam
• Copco 2 Dam
• Iron Gate Dam

GG Associates developed a report for American
Rivers, Trout Unlimited, California Trout,
Friends of the River, and the Klamath River
Intertribal Fish and Water Commission.
GG Associates, 2003, Investigation of Removal of
Four Lower Klamath River Dams, J. C. Boyle Dam,
Copco 1 Dam, Copco 2 Dam and Iron Gate Dam
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The scope of this investigation is feasibility
level only.
Specific information regarding volume, location,
and size of trapped sediment, specific dimensions
of structures, nature and extent of water use
downstream of the dams, and location of spoils
sites was either not available or developing such
information was beyond the scope of this report.
Numerous issues require more investigation before
final costs estimates can be completed. The
objective of this report is to determine whether
removal of the four lower Klamath River dams is
feasible from a construction and cost
perspective.
GG Associates, 2003, Investigation of Removal of
Four Lower Klamath River Dams, J. C. Boyle Dam,
Copco 1 Dam, Copco 2 Dam and Iron Gate Dam
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Studies conducted as part of the hydropower
re-licensing proceeding indicate that
cumulatively, all four dams trap approximately
14.4 million cubic yards of sediment, of which
approximately 87 is silt and clay and 13 is
sand or larger material.
GG Associates, 2003, Investigation of Removal of
Four Lower Klamath River Dams, J. C. Boyle Dam,
Copco 1 Dam, Copco 2 Dam and Iron Gate Dam
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Cost estimates developed for this study are based
on the assumption that sediment trapped behind
the dams would be naturally eroded downstream.
Information regarding the volume of sediment
trapped appears to be well developed but
information regarding grain size distribution of
trapped sediment appears to be insufficient to
determine how quickly the eroded sediment would
move through and out of the river system.
GG Associates, 2003, Investigation of Removal of
Four Lower Klamath River Dams, J. C. Boyle Dam,
Copco 1 Dam, Copco 2 Dam and Iron Gate Dam
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Review of available information regarding the
dams, trapped sediment, and river characteristics
indicates that removing the dams is feasible and
that the cost would be approximately 40 million.
Based on assumptions stated in this report, the
cost for removal would be 19.2, 1.9, 8.5, and
6.2 million respectively for Iron Gate, Copco 2,
Copco 1, and J.C. Boyle dams.
GG Associates, 2003, Investigation of Removal of
Four Lower Klamath River Dams, J. C. Boyle Dam,
Copco 1 Dam, Copco 2 Dam and Iron Gate Dam
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Effects of removal of a small dam on downstream
macroinvertebrate and algal assemblages in a
Pennsylvania stream
There is little empirical data on which to base
predictions about ecological responses to dam
removal. Less than 5 (20) of all dam removals
in the United States have been accompanied by
published ecological studies.
Most of the dams removed to date were relatively
small structures (usually lt15 ft. high).
Thomson, 2005, Effects of removal of a small dam
on downstream macroinvertebrate and algal, J. N.
Am. Benthol. Soc., 2005, 24(1)192207
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Effects of removal of a small dam on downstream
macroinvertebrate and algal assemblages in a
Pennsylvania stream
The authors examined the responses of benthic
macroinvertebrate and algal assemblages in
downstream reaches to the removal of a small,
run-of-river dam on Manatawny Creek,
Pennsylvania.
Benthic macroinvertebrates, algae, and habitat
characteristics were monitored upstream and
downstream of the dam for 4 months before
removal, 3 months after partial removal (i.e.,
when the impoundment was largely eliminated but
sediment remained trapped behind the remaining
structure), and 12 months after complete dam
removal.
Thomson, 2005, Effects of removal of a small dam
on downstream macroinvertebrate and algal, J. N.
Am. Benthol. Soc., 2005, 24(1)192207
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Effects of removal of a small dam on downstream
macroinvertebrate and algal assemblages in a
Pennsylvania stream
Macroinvertebrate density, algal biomass, and
diatom species richness declined significantly
downstream of the dam following complete dam
removal.
Downstream impacts occurred only after the dam
structure had been completely removed and
sediments had been transported downstream from
the former impoundment by high flows.
Thomson, 2005, Effects of removal of a small dam
on downstream macroinvertebrate and algal, J. N.
Am. Benthol. Soc., 2005, 24(1)192207
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Effects of removal of a small dam on downstream
macroinvertebrate and algal assemblages in a
Pennsylvania stream
Biotic impacts persisted for the duration of the
study (12 months after complete removal).
Our results and other studies of dam removal
suggest that downstream sedimentation following
dam removal can reduce densities of
macroinvertebrates and benthic algae and may
reduce benthic diversity,
but for small dams such impacts may be relatively
minor and will usually be temporary.
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Mouth of the Klamath River from Requa, CA.