Table Of ContentUnited States General Accounting Office
GP0
Report to Congre^srtSrtal Committees
October 1996 BUREAU OF
RECLAMATION
An
Assessment
of the
Environmental Impact
Statement on the
Operations of the Glen
Dam
Canyon
years
1921 -1996
GAO/RCED-97-12
GAO
United States
General Accounting Office
Washington, D.C. 20548
Resources, Community, and
Economic Development Division
B-272927
October2, 1996
The Honorable FrankMurkowski
Chairman
The HonorableJ. BennettJohnston
Ranking MinorityMember
Committee on Energy and Natural Resources
United States Senate
The Honorable Don Young
Chairman
The Honorable George Miller
Ranking Minority Member
Committee on Resources
House ofRepresentatives
This reportrespondsto subsection 1804(b) ofthe Grand Canyon ProtectionActof 1992 (title
XVIII ofP.L. 102-575), whichrequired gao to auditthe Bureau ofReclamation'sfinal
environmental impact statement on the operations ofthe Glen Canyon Dam. The report
discusses (1) whether Reclamation's determination ofthe impact ofvarious dam-operating
alternatives on selected resources was reasonable and (2) what, ifany, concernsstill exist on
thepart ofkeyinterestedparties aboutthe final impactstatement.
We areproviding acopy ofthis reporttothe Secretary ofthe Interior, theAssistant Secretary
forWater and Power, and the Commissioner ofthe Bureau ofReclamation. We will also make
copies available to others upon request.
Thisreportwasprepared underthe direction ofVictor S. Rezendes, Director, Energy,
Resources, and Science Issues, who can be reached at (202) 512-3841 ifyou oryourstaffhave
anyquestions. Major contributorsto thisreport are listed in appendix XIII.
Keith O. Fultz
Assistant Comptroller General
Summary
Executive
Purpose Since the Glen Canyon Dam, located in Page, Arizona, was completedby
the Bureau ofReclamation in 1963, ithasbeen used to generate power
duringperiods ofhigh demand, commonly known aspeakingpower. The
fluctuatingreleases ofwaterassociated with the dam'speakingpower
operationshave caused concerns aboutthe detrimental effects such flows
have on downstream resources, particularlythose located in the Grand
Canyon. In response to these concerns, the Secretary ofthe Interior, in
July 1989, directedthe Bureau ofReclamation to prepare an
environmentalimpact statementthatwouldreevaluate the Glen Canyon
Dam's operations. The purpose ofthe reevaluation wasto determine
specific options foroperatingthe dam thatcould minimize the adverse
impactsonthe downstream environmental andrecreational resources, as
well as on NativeAmericaninterests in the Glen and Grand canyons, while
stillproducing hydropower.
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Page2 GAO/RCED-97-12 Glen Canyon Dam'sEnvironmental ImpactStatement
ExecutiveSummary
In October 1992, the Congress enacted the Grand Canyon ProtectionAct
of 1992 (title XVIII ofP.L. 102-575), which requiredthe Secretary ofthe
Interior to complete the environmentalimpactstatementby October30,
1994. The actalso required that gaoauditthe costs and benefits ofthe
various operating alternativesidentified in the final environmental impact
statement. Inpreparing the statement, Reclamation studied the potential
impact ofvarious flow alternatives on selected resources. Reclamation
reported the results ofthese studiesin the final environmental impact
statement on March 21, 1995. As discussedwith the responsible
congressional committees, forthe purpose ofthisaudit, gao examined
(1) whether Reclamation'simpactdeterminationswere reasonable and
(2) what, ifany, concerns still existaboutthe Glen Canyon Dam's final
environmental impact statement. The act also requires that on the basisof
the findings, conclusions, and recommendations made in the
environmental impact statement and the gao auditreport, the Secretaryis
to adopt criteriaand operatingplans forthe dam.
Ftork""«?rminH Before the construction ofthe Glen Canyon Dam, the Colorado River's
sediment-laden flows fluctuated dramaticallyduring differentseasonsof
the year. Annual daily flows ofgreaterthan 80,000 cubic feetpersecond
were common duringthe springrunoff. In contrast, flows oflessthan
3,000 cubic feetper second were typical throughoutthe late summer, fall,
andwinter. Watertemperatures ranged from nearfreezinginthe winterto
more than 80 degrees Fahrenheitinthe summer. The construction ofthe
Glen Canyon Dam alteredthe natural dynamics ofthe Colorado River
corridorthroughthe Glen and Grand canyons. The dam replaced the
dramatic seasonal flowvariationswith significant daily fluctuations,
greatlyreduced the amount ofsedimentin the water, andresultedin
nearly constantwaterrelease temperatures ofabout46 degrees
Fahrenheit.
As earlyas 1982, the Secretary ofthe Interiorinitiatedthe Glen Canyon
Environmental Studies ofthe effects ofthe dam. These studieswere led by
Reclamationand conducted by anumber ofdifferentagencies. In 1989, the
Secretary designated Reclamation as the lead agencyin preparing an
environmental impact statement. Otheragenciesand individuals
participated in these efforts, including federal and state resource agencies,
Indian tribes, private consultants, universities, and river guides. Toprotect
the downstream resources until the completion ofthe impact statement
and the adoption ofanew operatingplan forthe dam, in November 1991
Reclamation implemented interim operating criteria The interim
Page3 GAO/RCED-97-12 GlenCanyonDam'sEnvironmental ImpactStatement
ExecutiveSummary
operating criteriareducedthe maximum peakreleases and daily
fluctuations. Withthepassage ofthe Grand Canyon ProtectionAct of 1992,
the Congressrequiredthatthe Glen Canyon Dam be operated toprotect
andrestore the downstream resources ofthe Grand Canyon National Park
andthe Glen Canyon National RecreationalArea
The National Environmental PolicyActof 1969 (42 U.S.C. 4321 et seq.)
requiresthatadetailed environmentalimpact statementbe prepared for
every majorfederalactionthatmay significantly affectthe quality ofthe
human environment. The actanditsimplementingregulations setforth the
requirements forpreparingan impactstatement. Among otherthings, a
statementmust(1) addressthe purpose ofand need forthe action,
(2) describe the environmentthatwillbe affected, (3) identify alternatives
tothe proposed action, (4) presentthe environmentalimpacts ofthe
proposed action (includingthe direct, indirect, and cumulative impacts),
and (5) identifythe agency'spreferred alternative. The act does not
require, and Reclamation did notperform, acostandbenefit analysis of
the proposedaction.
Inpreparingthe environmentalimpact statement forthe operation ofthe
Glen Canyon Dam, Reclamationidentified 11 resourcesaffected bythe
dam's operationsto be analyzed in detail: water, sediment, fish, vegetation,
wildlife and habitat, endangered and otherspecial-status species, cultural
resources, airquality, recreation, hydropower, and non-use value.
(Non-usevalues have been definedasthosevalues thatpeople may
receive from the knowledge thatsuch things asrare plantsand unspoiled
natural environments exist, evenifpeople do notconsume or use these
goods directly.)
Inaddition, the impactstatementidentified nine alternative operational
scenariosto be studiedin detail. These alternatives canbe divided into
three descriptive categories: unrestricted fluctuatingflows (two
alternatives, includingthe no-action alternative); restricted fluctuating
flows (fouralternatives); and steady flows (three alternatives).
In the finalimpactstatement, Reclamationrecommended the Modified
Low Fluctuating Flow asthepreferred alternative. This alternative was
developed to reduce daily flow fluctuationswell below the dam'sprevious
operatinglevelsand toprovide periodic high, steady releases ofshort
duration; the goal ofthisalternative wasto protect or enhance
downstream resourceswhile allowinglimited flexibilityforpower
operations.
Page4 GAO/RCED-97-12GlenCanyon Dam'sEnvironmental ImpactStatement
Executive Summary
m
P?p<iiiltQ in RHpf &eneral> Reclamation used appropriate methodologies and the best
available information in determining the potentialimpact ofthe dam's
various flow alternatives on selected resources, gao identified some
shortcomingsand controversyin Reclamation's application ofcertain
methodologies, and some ofthe datathat Reclamation used in makingits
impact determinations were dated, preliminary, orincomplete. These
limitations, combinedwith the inherentuncertaintyassociatedwith
making forecasts, reduces the precision ofthe impacts contained inthe
statement, and some uncertainty, such asthe impact ofsteady flows on
fishresources, remains. Nonetheless, accordingto gao'sanalysis and the
opinions ofexperts, these limitations are notsignificant enoughto alter
the relative rankingofthe flow alternatives norrenderthe final
environmentalimpactstatement unusable asadecision-making document.
Furthermore, Reclamation recognizesthatuncertaintiesstill exist. To
address these concerns, Reclamationintendstoinitiate aprocess of
"adaptive management" that would provide forlong-term monitoring and
research to measure the actual effects ofthe selected alternative. The
results ofthis effortwould form the basis forpossible future modifications
ofthe dam's operations.
Many ofthe keyinterestedparties affected bythe Glen Canyon Dam's
environmental impact statement supportthe process used by Reclamation
to develop the impact statement as well asthe implementation ofthe
preferred alternative. However, while expressingtheirsupport, some
interestedparties raised specific concernsthatstill existaboutthe final
environmental impactstatement, including (1) the mannerin which
compliance with the Endangered SpeciesActwillbe achieved, (2) the
economic impact ofreducingthe Glen Canyon Dam's hydroelectric power
capacity, (3) the consideration ofotherpossible causes ofadverse
downstream impacts, (4) the difficulties inmeasuring the impactof
changesinthe dam's operations, (5) the adequacy ofthe measures for
reducing the frequencyofunscheduled floods, (6) the need forinstalling
multilevel waterintake structures (selective withdrawal structures) on the
dam to raise the downstream watertemperature, and (7) the
implementation ofthe Adaptive Management Program.
Page5 GAO/RCED-97-12 GlenCanyonDam'sEnvironmental ImpactStatement
ExecutiveSummary
Principal Findings
Impact Determinations Are Inpreparingthe environmentalimpactstatement, Reclamation used a
Usable for variety ofmethodologies and datasourcesto studythe impactofthe
Decision-Making various dam flow alternatives on hydropower, non-usevalues and other
resourceslocated below the dam. Generally, gao found the methodologies
usedto be reasonable and appropriate. Forexample, the power analysis
was conducted by acommittee ofspecialists representingthe federal
government, the utilityindustry, private contractors, and the
environmental community. This committee used utility-specific dataand
state-of-the-art simulation models to estimate the economic impactofthe
alternative dam flows onlarge regional utilities.
In assessing Reclamation's implementation ofthe various methodologies,
gao did note several shortcomings and controversy overthe methodology
used to estimate non-use values. For example, in the hydropoweranalysis,
Reclamation's assumptions do not explicitlyincludethe mitigating effect
ofhigherelectricityprices on electricity demand (price elasticity), gao
also foundthat Reclamation's assumptionsaboutfuture natural gasprices
were relativelyhighand thattwo computational errorswere made during
the thirdphase ofthe poweranalysis. These limitations suggestthatthe
estimated economic impacts forpowerare subjectto uncertainty.
However, Reclamation and many experts associated with the process do
notbelieve thatthese limitations make the results ofthe analysisunusable.
For example, an associationthatrepresentsthe affectedpowerutilities,
whichhas maintained throughoutthe powerstudiesprocessthatthe
impactstatement understates the coststo the power system, does not
believe that Reclamation's costestimate is understated by alarge
magnitude. To quantify the impactofvarious dam flow alternatives on
recreationand non-usevalue, Reclamation used amethodology called
contingentvaluation. The use ofcontingentvaluation studies, which rely
on surveys to elicitinformation from consumersto estimate how much
theywould be willing to pay forsomethingis controversial. Although
contingentvaluationis currentlythe only known approach forestimating
non-usevalues, some prominent economistsquestionwhetherthis
methodology can accurately elicitthe value consumers place on non-use
goods. However, many economistsand survey researchers working in the
natural resource and environmental areas have developed and used this
methodology. Although these shortcomings affectthe estimates for the
Page6 GAO/RCED-97-12 GlenCanyonDam'sEnvironmental ImpactStatement
Executive Summary
alternatives, itis unlikelythattheywould altertherelative ranking ofthe
fluctuatingand steadyflow alternatives.
gao also found that Reclamation generally used the best available datain
makingitsimpact determinations. Forexample, forinformation on
culturalresources andproperties, Reclamation wentbeyond the federal
requirements forthe development ofanimpact statementbyperforming
assessments ofall previouslyidentified archeological siteswithinthe
Colorado Rivercorridorinthe Glenand Grand canyons. Accordingto
many experts, when completed, this effort generated the bestand most
currentscientific information available. However, gao also found some
limitationsinthe datausedin the development ofthe impactstatement.
Specifically, some ofthe informationwas dated, some waspreliminary,
and some wasincomplete. For example, to assessthe economic impact of
the alternative flows on recreational activities, Reclamation used a 1985
survey ofasample ofanglers, day-rafters, andwhite-waterboaters that
askedabouttheirexperiences onthe Colorado Riverandwhat effect, if
any, differentstreamflowswould have on theirrecreational experiences.
Although Reclamation updated some ofthe datato 1991, it acknowledges
thatthe surveyinformationis generally dated. The National Research
Council generally foundthe analysis tobe adequate.
Many ofthe results ofthe sedimentstudies at Glen Canyon were
preliminary, were in draftform, and had notbeenpublished atthe time
thatthe draftoreventhe final impactstatementwaswritten. However,
accordingto the researchersthat gao interviewed, no new oradditional
information on sedimentimpactshasbeen obtainedthatwould alterthe
information orconclusionspresented in the final impactstatement.
Finally, the information on some resources isincomplete, asisthe
knowledge ofhow changes inthe Glen Canyon Dam's operationswill
affectthose resources. For example, inpartbecause ofincomplete data,
the experts' opinionsvary on the interactions between native and
normative fish and how operational changes would affectthese
interactions and, ultimately, fish populations. In its final biological
opinion, the U. S. Fish and Wildlife Service stated that Reclamation's
preferred alternative forthe dam's future operations, the Modified Low
FluctuatingFlow alternative, is likely tojeopardize the existence oftwo
native endangered fish species (the humpback chub and the razorback
sucker). The Service identified actions thatwould modify the preferred
alternative with seasonally adjusted steady flows. The Service and
Reclamation agreed to categorize these flowsas experimental, orresearch
Page7 GAO/RCED-97-12 GlenCanyon Dam'sEnvironmental ImpactStatement
Executive Summary
flows. The purpose ofthisresearchis to studythe effects ofsteady flows
on endangered and native fish.
Reclamationrecognizes that many uncertainties aboutthe actualimpactof
the various flow alternatives still exist. To address such concerns,
Reclamation intendsto initiate aprocess of"adaptive management" that
wouldprovide forlong-term monitoring, research, and measurement of
the effects ofthe selected alternative. The results ofthis effortwould form
the basis forfuture modifications ofthe dam's operations.
Most Key Parties Support The process for selectingapreferred alternative forthe future operations
the Preferred Alternative, ofthe Glen Canyon Dam considered many factors, such asprotecting
but Some Concerns natural and cultural resources and maintaining hydropower generating
Remain capability, andinvolved manypartieswith diverse interests. Reclamation's
goalwasto selectan alternative dam-operatingplanthatwouldpermit
downstream resourcesto recoverto acceptable long-term management
levels while maintaining some level ofhydropowerflexibility. Reclamation
believesthatitaccomplished this goal by selectingthe Modified Low
Fluctuating Flowasthe preferred alternative. Accordingto Reclamation,
this flowalternative was developedto reduce daily flow fluctuations well
below the dam's historic operations andtoprovideperiodic high, steady
waterreleases ofshort duration with the goal ofprotecting orenhancing
the downstream resourceswhile allowinglimited flexibility forpower
operations. Thisalternative hasthe same annual and essentially the same
monthlywaterreleases asthe dam's historic operationsbutwould restrict
daily and hourlywaterreleases more thanpreviously.
gaojudgmentally selected37 keyinterestedpartiesand surveyedthem on
whether they supported Reclamation'spreferred alternative and whether
they have any remaining concerns aboutimplementingthis alternative as
the future operatingplan forthe Glen Canyon Dam. gao'sjudgmental
sample consisted ofall ofthe organizations and individualsthat
Reclamationidentified as providing significant comments on the draft
impact statement, any organizationsthatwere considered cooperating
agencies inthe impactstatement's developmentprocess, and otherkey
interested parties. Over 83 percent (25 of30) ofthe respondents to gao's
survey supported the preferred alternative, and many expressed support
forthe process used by Reclamation to develop the impact statement. Of
the five remainingrespondents, three stated thatthey had no position on
the issue, while two, the SanJuan Southern Paiute Tribe andthe Grand
Canyon River Guides, believed thatthe currentinterim operating criteria
Page8 GAO/RCED-97-12 GlenCanyonDam'sEnvironmental ImpactStatement
