Attach_04 Page 1 of 24

Glen Canyon Dam

Adaptive Management Work Group

Ad Hoc Committee on Strategic Planning

Report to AMWG, January 2001

Addendum

This report is intended to augment the materials sent to Adaptive Management 

Work Group (AMWG) members in preparation for your meeting January 11-12, 

2001.

In the weeks since the packet for this meeting was sent out, the AMWG Ad Hoc 

Committee on Strategic Planning (AHC) has continued refining the Strategic 

Planning document. Small groups of TWG members and outside scientists, 

chaired by AHC members, have made numerous recommendations for changes and 

refinements to the Management Objectives (MOs). The Technical Work Group 

members have reviewed those recommendations and made suggestions of their 

own. The attached document shows how the MOs, and particularly the qualitative 

targets, have changed based on that input since the version of the document you 

saw at your last meeting. The AHC felt that because the AMWG will be asked to 

approve the qualitative targets at the meeting, it was important for members to use 

the most recent version. Note that the AHC has reviewed in detail the small group 

recommendations for Goals 1 through 7 only.

Current and target levels and the comments column have been deleted from this 

version, as they are not the subject of approval by the AMWG at this meeting. The 

vision and mission are not included because no changes are proposed for them.

In addition to changes to the MOs, several of the Goals and Principle 8 have been 

modified, as well. Those changes, like the changes to the MOs, are on the agenda 

for your approval at the upcoming meeting, and all are redlined for your 

convenience.
Principles

Attach_04 Page 2 of 24

The Glen Canyon Dam Adaptive Management Work Group embraces the following 

Principles. They guided development of the Goals and Objectives for the Glen Canyon 

Dam Adaptive Management Program (GCDAMP). These Principles are:

1. The Goals represent a set of desired outcomes that together will accomplish our 

Vision and achieve the purpose of the Grand Canyon Protection Act. Some of the 

Objectives and actions that fall under these Goals may not be the responsibility of 

the GCDAMP, and may be funded by other sources, but are included here for 

completeness.

2. The construction of Glen Canyon Dam and the introduction of non-native species 

have irreversibly changed the Colorado River ecosystem.

3. Much remains unknown about the Colorado River ecosystem below Glen Canyon 

Dam and how to achieve GCDAMP ecosystem Goals.

4. The Colorado River ecosystem is a managed ecosystem. An ecosystem 

management approach, in lieu of an issues, species, or resources approach, will 

guide our efforts. Management efforts will prevent any further human-induced 

extirpation or extinction of native species.

5. An adaptive management approach will be used to achieve GCDAMP ecosystem 

Goals, through experimentation and monitoring, to meet the intent of the Grand 

Canyon Protection Act, the Environmental Impact Statement, and the Record of 

Decision. 

6. Management actions, including changes in dam operations, will be tried that 

attempt to return ecosystem patterns and processes to their range of natural 

variability. When this is not appropriate, or beyond the range of operational 

flexibility of the dam, experiments will be conducted to test other approaches.

7. Because management actions to achieve a Goal may benefit one resource or value 

and adversely affect another, those action alternatives that benefit all resources and 

values will be pursued first. When this is not possible, actions that have a neutral 

impact, or as a last resort, actions that minimize negative impacts on other 

resources will be pursued, consistent with the final Glen Canyon Dam EIS and the 

Record of Decision.

8. If the target of a management objective proves to be inappropriate, unrealistic, or 

unattainable, the AMP will reevaluate that target and the methods used to attain it.

9. Recognizing the diverse perspectives and spiritual values of the stakeholders, the 

unique aesthetic value of the Grand Canyon will be respected and enhanced.
Goals

Attach_04 Page 3 of 24

1. Protect or improve the aquatic foodbase so that it will support viable 

populations of desired species at higher trophic levels.

2. Maintain or attain viable populations of existing native fish and remove 

jeopardy from humpback chub and razorback sucker.

3. Restore populations of extirpated species, as feasible and advisable.

4. Maintain a wild reproducing population of rainbow trout above Lees 

Ferrythe Paria River, to the extent practicable and consistent with the 

maintenance of viable populations of native fish.

5. Maintain or attain viable populations of Kanab ambersnail.

6. Protect or improve the biotic riparian and spring communities.

7. Establish water temperature, quality, and flow dynamics to achieve 

GCDAMP ecosystem goals.

8. Increase fine Maintain or attain levels of sediment storage within the 

main channel and along shorelines to achieve GCDAMP ecosystem 

goals.

8. Protect the presence of Southwest willow flycatcher in a manner consistent 

with ecosystem goals.

9. Maintain or improve the quality of recreational experiences for users of 

the Colorado River ecosystem, within the framework of GCDAMP 

ecosystem goals.

10.Maintain or increase powercapacity and energy generation, and 

increase where feasible and advisable, within the framework of 

GCDAMP ecosystem goals.

11.Preserve, protect, manage, and treat cCultural resources within the river 

corridor shall be preserved, protected, managed and treated for the 

inspiration and benefit of past, present and future generations.

12.Maintain a high-quality monitoring, research, and adaptive 

management program. (These goals are now part of Goal 12: Build a 

broad, effective, outreach program. Broaden the funding base to 

achieve GCDAMP goals and objectives.)
Goal 1. Protect or improve the aquatic foodbase so that it will support viable populations of desired species at higher trophic levels

MO 

#

Perform 

some 

action

On some 

element

On some 

attribute At some place Qualitative Target

Attach_04 Page 4 of 24

Biomass

Composition

1.1 

(1 

and 

3)

Maintain or 

attain

Primary 

producers: 

algae on hard 

substrates, 

rooted 

macrophytes 

on soft 

substrates, and 

diatomsAlgae 

and periphyton

Production

Mainstem from 

Glen Canyon 

Dam to the 

Paria River in 

both pools and 

on cobble bars 

identified by 

specific 

sampling sites

Biomass

Composition

1.2

(2)

Maintain or 

attain

Benthic 

invertebrates

Production

Mainstem from 

Glen Canyon 

Dam to Paria 

River

Biomass

Composition

3 Maintain or 

attain

Aquatic 

macrophytes

Production

Mainstem from 

Glen Canyon 

Dam to Paria 

River

Biomass

Composition

1.3 

(4 

and 

6)

Maintain or 

attain

Primary 

producers: 

algae on hard 

substrates, 

rooted 

macrophytes 

on soft

substrates, and 

diatoms Algae 

and periphyton

Production

Mainstem 

below the 

Paria River on 

cobble bars 

identified by 

specific 

sampling sites

The target for all the Management Objectives in Goal 1 is adequate food 

availability to support trout and native fish above the Paria River, and native fish 

below the Paria River.

.

Biomass

Composition

Production 

1.4

(5)

Maintain or 

attain

Benthic 

invertebrates

Distribution

Mainstem 

below the 

Paria River
Goal 1. Protect or improve the aquatic foodbase so that it will support viable populations of desired species at higher trophic levels

MO 

#

Perform 

some 

action

On some 

element

On some 

attribute At some place Qualitative Target

Attach_04 Page 5 of 24

Biomass

Composition

Production

6 Maintain or 

attain

Aquatic 

macrophytes

Distribution

Mainstem 

below the 

Paria River

1.5 Abundance

(7)

Maintain or 

attain

Foodbase drift: 

Diptera

Gammarus

Other Bugs

CPOM(a)

FPOM(b)

DOC

Composition

Mainstem 

below GCD

The target for all the Management Objectives in Goal 1 is adequate food 

availability to support trout and native fish above the Paria River, and native fish 

below the Paria River.

(a) Coarse particulate organic matter

(b) Fine particulate organic matter
Goal 2. Maintain or attain viable populations of existing native fish and remove jeopardy from humpback chub and razorback sucker.

MO 

#

Perform 

some 

action

On some 

element

On some 

attribute At some place Qualitative Target

Attach_04 Page 6 of 24

LCR aggregation (a) LCR 

and mainstem within 3 

miles of LCR

2.1 

(8)

Maintain 

or attain

Humpback 

chub (150 mm 

and larger)

[Length is 

based on the 

size at which a 

HBC is able to 

be pit-tagged.]

Abundance

Eight mainstem 

aggregations Mainstem 

except within 3 miles of 

the LCR

The target is viable populations and removal of jeopardy.

LCR aggregation LCR and 

mainstem within 3 miles of 

LCR

2.2 

(9)

Maintain 

or attain

Humpback 

chub (51 mm 

to 150 mm)

Year class 

strength 

Abundance

Eight mainstem 

aggregations Mainstem 

except within 3 miles of 

the LCR

The target is viable populations and removal of jeopardy.

2.3 LCR aggregation 

(new)

Maintain 

or attain

Humpback 

chub (> 200 

mm) 

[This is the 

length at which 

50% of the fish 

are thought to 

be sexually 

mature.]

Recruitment

Eight mainstem 

aggregations 

The target is viable populations and removal of jeopardy.

2.4 

(10)

Establish Humpback 

chub

Spawning 

aggregation 

Populations

CRE downstream of GCD The target is viable populations and removal of jeopardy.

(a) The definition of the LCR aggregation will be resolved following completion of the stock assessment workshop and the PEP review.
Goal 2. Maintain or attain viable populations of existing native fish and remove jeopardy from humpback chub and razorback sucker.

MO 

#

Perform 

some 

action

On some 

element

On some 

attribute At some place Qualitative Target

Attach_04 Page 7 of 24

LCR aggregation LCR and 

mainstem within 3 miles of 

LCR

Condition

Eight mainstem 

aggregations Mainstem 

except within 3 miles of 

the LCR

LCR aggregation LCR and 

mainstem within 3 miles of 

LCR

2.5 

(11)

Attain Humpback 

chub

Disease and 

other parasites

Health

Eight mainstem 

aggregations Mainstem 

except within 3 miles of 

the LCR

The target is viable populations and removal of jeopardy.

LCR and mainstem within 

3 miles of LCR

(12) Maintain 

or attain

Humpback 

chub

Spawning

Mainstem except within 3 

miles of the LCR

LCR

CRE below GCD

Mortality due 

to non-native 

fish predation 

as a % of 

overall 

mortality

Predation on 

native fish

Mainstem

2.6 

(13)

Reduce Native 

Non-native 

fish

Competition 

with native 

fish

CRE below GCD

The target is reduction of non-native fish predation and competition so it 

does not impinge on native fish viability.

2.7 

(14)

Attain Razorback 

sucker

Abundance 

Populations

CRE below GCD Target is derived from the capability of the habitat to support the 

species.
Goal 2. Maintain or attain viable populations of existing native fish and remove jeopardy from humpback chub and razorback sucker.

MO 

#

Perform 

some 

action

On some 

element

On some 

attribute At some place Qualitative Target

Attach_04 Page 8 of 24

Flannelmouth Abundance

sucker Distribution 

Bluehead Abundance

sucker Distribution

Abundance

2.8 

(15)

Maintain

Speckled dace

Distribution

CRE below GCD

The target is viable populations and removal of jeopardy.
Goal 3. Restore populations of extirpated species, as feasible and advisable.

MO 

#

Perform 

some 

action

On some 

element

On some 

attribute At some place Qualitative Target

Attach_04 Page 9 of 24

Colorado 

pikeminnow

Bonytail

Roundtail 

Chub

3.1 

(16)

Restore

River otter

Abundance CRE 

downstream of 

GCD See goal.
Goal 4. Maintain a wild reproducing population of rainbow trout above Lees Ferrythe Paria River, to the extent practicable and consistent with the 

maintenance of viable populations of native fish.

MO 

#

Perform 

some action

On some 

element

On some

attribute At some place Qualitative Target

Attach_04 Page 10 of 24

Abundance Target is the level at which trout do not impinge on native fish.

Proportional 

stock density

(see below)

Length at age 

Growth rate

Condition

Whirling 

disease and 

other parasitic 

infections

Health

Spawning

habitat

See goal.

4.1

(17)

Maintain 

or attain

Rainbow trout

Natural 

recruitment

Mainstem from 

Glen Canyon 

Dam to Paria 

River

This MO restates and measures the goal.

4.2

new

Limit Lees Ferry 

Rainbow trout

Distribution CRE below the 

Paria River

The target is minimal competitive or predator / prey effect on downstream native fish.

Proportional Stock Density is the ratio that results by dividing the number of fish great than 16” by the number of all fish greater than 12”. This provides a 

measure of the abundance of fish at a certain size, which should translate into a target for both abundance and length at age.
Goal 75. Establish water temperature, quality, and flow dynamics to achieve GCDAMP ecosystem goals.

MO 

#

Perform 

some 

action

On some 

element

On some 

attribute At some place Qualitative Target

Attach_04 Page 11 of 24

Temperature 

range

7.1 

(18)

Attain Water

Seasonal 

variability of 

temperature

Mainstem The target is a temperature range and pattern of seasonal variability based on the 

range of natural variability, the range of operational flexibility of the dam, the range 

of legal flexibility, and the range that optimizes conditions for the targeted featured 

resources. Targeted resources are foodbase, native fish, trout, and people (human 

health and safety – microorganisms and hypothermia).

Temperature patterns should have as their first priority the improvement of conditions 

for native biological resources, including native fish, and including foodbase and 

trout interactions. This is based on the special status of native fish.

7.2 

(19)

Maintain Water Quality Mainstem The target is water quality based on the range of natural variability, the range of 

operational flexibility of the dam, the range of legal flexibility, the legally-defined 

state water quality standards, and the range that optimizes conditions for the targeted 

featured resources. The targeted resources are foodbase, native fish, trout, 

Southwestern willow flycatcher, riparian and spring communities, the recreational 

experience, and cultural resources.

Power plant 

operations

BHBF flows

7.3 

(20)

Maintain Flow dynamics

Habitat 

maintenance 

flows

Mainstem

See goal.
Goal 86. Increase fine Maintain or attain levels of sediment storage within the main channel and along shorelines to achieve GCDAMP ecosystem goals.

MO 

#

Perform 

some 

action

On some 

element

On some 

attribute At some place Qualitative Target

Attach_04 Page 12 of 24

Abundance

Grain-size

8.1

(21)

Maintain 

or attain

Fine Ssediment

Distribution 

Main channel 

up to power 

plant capacity

Abundance

Grain-size

8.2 

(22)

Maintain 

or attain

Fine Ssediment

Distribution

Eddies up to 

25,000 cfs 

power plant 

capacity

Abundance

Grain-size

8.3 

(23)

Maintain 

or attain

Fine Ssediment

Distribution

Shorelines 

between

25,000 cfs

power plant 

capacity and 

maximum 

BHBF

The target for Goal 8 is enough sediment to achieve the biological, recreational, and 

cultural goals. Given limited sediment inputs, we need to retain enough sediment in 

the system to achieve ecosystem patterns in these goals. For the biological goals, the 

purposes are habitat and nutrient storage. For the cultural goal, the purposes are plant 

habitat and preserving sites through filling in arroyos and replenishing the terraces 

with sediment. For recreational goals, the purposes are camping beaches and trout 

spawning habitat.
Goal 57. Maintain or attain viable populations of Kanab ambersnail.

MO 

#

Perform 

some 

action

On some 

element

On some 

attribute At some place Qualitative Target

Attach_04 Page 13 of 24

5.1 

(24)

Attain and 

maintain

Kanab 

ambersnail

Population Vasey’s 

Paradise Target is a viable population.

5.2 

(25)

Maintain Kanab 

ambersnail

Habitat Above some 

stage level at 

Vasey’s 

Paradise (stage 

level is an 

Information 

Need)

Target is level needed to sustain a viable population.
Goal 8. Protect the presence of southwestern willow flycatcher and its critical habitat in a manner consistent with riparian ecosystem goals.

MO 

#

Perform 

some 

action

On some 

element

On some 

attribute At some place Qualitative Target

Attach_04 Page 14 of 24

Abundance CRE below 

GCD

The target is the number of breeding pairs that the habitat is capable of supporting.

Distribution CRE below 

GCD

The target is the distribution of breeding pairs that the habitat is capable of 

supporting.

(26) Maintain 

or increase

Southwest 

willow 

flycatcher

Fledging 

success

CRE below 

GCD

6.8 

(27)

Maintain Southwest 

willow 

flycatcher

Riparian 

Critical habitat

CRE below 

GCD, and 

especially from 

Separation to 

Lake Mead

The target is the capability of the habitat to support the species. The target is For a 

dynamic mosaic of NHWZ, OHWZ, and marsh vegetation. The NHWZ should be 

dominated primarily by willows and/or tamarisk at least 4 meters high and in patches 

at least 20 meters wide.

(28) Reduce Brown-headed 

cowbird

Brood 

parasitism

CRE
Goal 69. Protect or improve the biotic riparian and spring communities.

MO 

#

Perform 

some 

action

On some 

element

On some 

attribute At some place Qualitative Target

Attach_04 Page 15 of 24

Abundance

Composition Target is no loss of native species.

6.1 

(29)

Maintain Marsh

Area

Distribution

CRE below 

GCD

Patch number 

and 

distribution 

Abundance

In all river reaches where it was documented by 

aerial photography in 1984, the target is to allow for 

scouring of some NHWZ vegetation due to periodic 

high flows, and to allow its return through 

successional processes.

Composition Target is to allow no loss of native plant or animal 

species.

6.2

(30)

Maintain New high 

water zone

community

Area 

Distribution

CRE below 

GCD

Abundance Target is no loss of area.

Composition

6.3 

(31)

Maintain Old high water 

zone

Distribution

CRE below 

GCD

Abundance

Composition

6.4 

(32)

Maintain Sand beach

Distribution

CRE below 

GCD

6.5 Abundance

(33)

Maintain Culturally 

important 

species Distribution

CRE below 

GCD

Abundance The target is the level at which these species do not 

impinge on biological, recreational, and cultural 

resources.

6.6 

(34)

Reduce Invasive nonnative species

Distribution

CRE below 

GCD

The target is no spreading of invasive non-native 

species to areas where they do not already occur

The target for the goal as a 

whole is an achievable and 

appropriate mix of fourthese 

types of communities: 

marsh, open sand beach, old 

high water zone (OHWZ), 

and new high water zone 

(NHWZ). All four 

communities are important 

for maintaining the diversity 

of wildlife. The Old High 

Water Zone is a high 

priority because of the threat 

of losing it. One way of 

maintaining it is through 

high flows, which may have 

a negative effect on marshes 

and New High Water Zones. 

Considering the legal and 

regulatory mandates of the 

NPS to protect natural 

landscapes and native 

species and communities, 

considering regenerative 

capabilities, and recognizing 

the dynamic and 

successional nature of these 

communities, the other three 

zones would be a lower 

priority.
Goal 69. Protect or improve the biotic riparian and spring communities.

MO 

#

Perform 

some 

action

On some 

element

On some 

attribute At some place Qualitative Target

Attach_04 Page 16 of 24

6.7

new

Maintain Spring and 

wetland

Habitat 

occupied by 

rare and 

endemic 

species

CRE below 

GCD 

The target is to maintain the capability of these habitats to support the rare and 

endemic species known to live there. The targets should recognize the dynamic 

nature of these habitats as influenced by flow events.
Goal 910. Maintain or improve the quality of recreational experiences for users of the Colorado River ecosystem, within the framework of GCDAMP 

ecosystem goals.

MO 

#

Perform 

some 

action

On some 

element

On some 

attribute At some place Qualitative Target

Attach_04 Page 17 of 24

9.1

(35)

Maintain Visitor Physical access 

and safety

Mainstem

9.2

(36)

Maintain 

or improve

Recreational 

spectrum

Quality and 

quantity

Glen Canyon

Size

Quality

Number

9.3

(37)

Maintain 

or increase

Camping 

beaches

Distribution

Mainstem

The target level should be within the capacity of the CRE to absorb visitor impacts. 

The target level should consider GLCA and GRCA Management Plans. See Myers et 

al.(25)

9.4

(38)

Maintain 

or improve

Rapids Navigability Mainstem The target level is to be developed from NPS on-river accident rates. See Myers et 

al.(25) The target should address navigability across the range of flows allowed within 

the ROD. The metric is the number of accidents per rapid at each flow.

9.5

(39)

Maintain 

or enhance

Experience Wilderness Grand Canyon Metric to include parameters for primitive character, unconfined experience, 

undeveloped natural and wild character, opportunities for solitude, sounds of nature 

and scenic beauty.
Goal 1011. Maintain or increase powercapacity and energy generation, and increase where feasible and advisable, within the framework of GCDAMP 

ecosystem goals.

MO 

#

Perform 

some 

action

On some 

element

On some 

attribute At some place Qualitative Target

Attach_04 Page 18 of 24

10.1

(40)

Maintain 

or increase 

Power Generation 

flexibility 

GCD See goal.
Goal 1112. Preserve, protect, manage, and treat Ccultural resources within the river corridor shall be preserved, protected, managed and treated for the 

inspiration and benefit of past, present and future generations.

MO 

#

Perform 

some 

action

On some 

element

On some 

attribute At some place Qualitative Target

Attach_04 Page 19 of 24

11.1

(41)

Preserve Registereligible 

properties

National 

Register 

integrity

APE The target is to preserve register-eligible properties via protection, management, 

and/or treatment (data recovery) for the purpose of federal agency compliance with 

NHPA, and AMP and AMWG compliance with GCPA.

11.2

(42)

Preserve Other cultural 

resources

Cultural values CRE The target is to preserve (stabilize or improve based on current cultural values) other 

traditionally important resources that are not sufficiently addressed under other MOs.

11.3

(43)

Attain and 

maintain

Management 

action

Consultation CRE The target is to achieve effective, legally mandated consultation.

11.4

(44)

Protect and 

maintain

Traditional 

cultural 

resources

Physical access CRE The target is designed to prevent AMWG from undertaking events that might restrict 

or block physical access by Native American religious practitioners, without 

meaningful consultation.

11.5

(45)

Integrate Information Cultural and 

other resources

CRE The target is to ensure that data is able to be used both for increased understanding of 

the past and for ongoing interactions of humans within the CRE.
Goal 12. Maintain a high-quality monitoring, research, and adaptive management program.

MO 

#

Perform 

some 

action

On some 

element On some attribute At some place Qualitative Target

Attach_04 Page 20 of 24

Hydropower N/A

Air quality N/A

Wilderness N/A

Recreation N/A

Non-use values N/A

12.1

(46)

Maintain 

or attain

Socioeconomic data

Tribal & spiritual values N/A

The target level is how much socioeconomic data is needed for adequate 

decision-making.

12.2

(47)

Attain and 

maintain 

Monitoring 

and research 

program

Natural, cultural, and recreational 

resources

CRE See goal.

That acknowledges uncertainty 

and uses experimentation, 

monitoring & research

12.3

(48)

Attain and 

maintain 

AMP 

composed of 

all 

stakeholders Participation

N/A See goal.

12.4

(49)

Attain and 

maintain

Funding Tribal participation AMP The target is a level of funding adequate to meet each tribe’s needs to 

participate in the Adaptive Management Program.

12.5

(50)

Conduct Experimental 

flows

Flow dynamics MainstemTarget level is the experiments needed to gain critical understanding of 

ecosystem function under different dam operations.

12.6

(51)

Conduct Management 

experiments

Other management actions CRE Target level is the experiments needed to gain critical understanding of 

ecosystem function under different management alternatives outside of dam 

operations.

12.7

(52)

Build AMP Public support N/A The target is adequate public support for AMP experiments and adaptive 

management, and a diverse funding base.

Foundation and Corporate N/A

Appropriated N/A

State Agency N/A

12.8

(53)

Maintain 

or attain

Funding

Power revenues N/A

The target is adequate funding to meet the goal.

12.9

(54)

Maintain 

or attain

Participation Externally-funded investigators CRE The target is contributions to meeting Information Needs by externally 

funded investigators.
Glossary

Attach_04 Page 21 of 24

ADAPTIVE MANAGEMENT

Adaptive management is an iterative process, designed to experimentally compare selected management 

actions by evaluating alternative hypotheses about the ecosystem being managed. It consists of three 

parts: management actions, monitoring, and adaptation. Management actions are treated as experiments 

subject to modification. Monitoring is conducted to detect the effects of the management actions. 

Finally, management actions are refined based on the enhanced understanding about how the ecosystem 

responds.

AREA OF POTENTIAL EFFECT

BIODIVERSITY

Biodiversity is “the variety of organisms considered at all levels, from genetic variants belonging to the 

same species through arrays of species to arrays of genera, families, and still higher taxonomic levels 

[including] ... the variety of ecosystems...”(38)

BIOLOGICAL GOALS

Biological goals include Goal 1 (foodbase), Goal 2 (native fish), Goal 3 (extirpated species), Goal 5 

(Kanab ambersnail), and Goal 6 (riparian and spring communities).

BIOTIC COMMUNITY

A biotic community is a “group of organisms ... that co-occur in the same habitat or area and interact 

through trophic and spatial relationships....”(20) 

CAPACITY (GENERATING)

Generating capacity is a measure of the ability to generate electric power, usually expressed in MW 

(megawatts). The capacity of a hydropower plant is a function of head (reservoir elevation) and 

maximum water flow through the turbines.

COLORADO RIVER ECOSYSTEM

The Colorado River ecosystem is the Colorado River mainstem corridor and interacting resources in 

associated riparian and terrace zones, located primarily from the forebay of Glen Canyon Dam to the 

western boundary of Grand Canyon National Park. It includes the downstream inundation level to which 

dam operations impact physical, biological, recreational, cultural, and other resources. The scope of 

GCDAMP activities may include limited investigations into some tributaries (e.g., the Little Colorado and 

Paria Rivers).

CONCEPTUAL MODEL

A conceptual model is an “assessment of the dynamics of the more important compartments and fluxes of 

material or energy in a system [i.e., patterns and processes], or of changes in a population.”(20) A 

conceptual model is a heuristic tool to provide a framework for thinking about how an ecosystem 

functions and to discover gaps in our knowledge. 

CULTURAL GOAL

Cultural goal refers to Goal 11.

CULTURAL RESOURCES

Cultural resources includes, but is not necessarily limited to, any prehistoric or historic district, site, 

building, structure, landscape, or object included in, or eligible for inclusion in the National Register, 

including artifacts, records, and material remains related to such a property or resource. Properties of 
Glossary

Attach_04 Page 22 of 24

traditional religious and cultural importance to an Indian tribe are included in this definition under Section 

101(d)(6)(A) of NHPA. 

ECOSYSTEM

An ecosystem is “a community of organisms and their physical environment interacting as an ecological 

unit.”(20) An ecosystem consists of patterns and processes that are dynamic and occur within a particular 

range of temporal and spatial variability. 

ECOSYSTEM INTEGRITY

Ecosystem integrity is “the ability to support and maintain a balanced, integrated, adaptive biological 

system having the full range of elements (genes, species, and assemblages) and processes (mutation, 

demography, biotic interactions, nutrient and energy dynamics, and metapopulation processes) expected 

in the natural habitat of a region.”(13) Ecosystem integrity is related to ecosystem resilience (i.e., the 

capacity to maintain characteristic patterns and processes) following a disturbance. 

ECOSYSTEM MANAGEMENT

An ecosystem management approach differs from an issue-, species-, or resource-specific approach. 

Ecosystem management is a method for sustaining or restoring ecosystems and their functions and values. 

“It is goal driven, and it is based on a collaboratively developed vision of desired future conditions that 

integrates ecological, economic, and social factors. It is applied within a geographic framework defined 

primarily by ecological boundaries.”(11) Ecosystem management is a process that attempts to mimic 

appropriate ecosystem patterns (abundance and distribution of species and habitats) and ecosystem 

processes (drivers of ecosystem patterns). It includes managing for viable populations of all native 

species.

ECOSYSTEM PATTERNS

Ecosystem pattern is the abundance of species, biotic communities, and physical habitats, as well as their 

spatial and temporal distribution. This is a broader concept than “composition and structure.” 

Composition usually refers only to species presence or absence, and structure usually refers to the 

distribution of biotic communities.

ECOSYSTEM PROCESSES

Ecosystem processes are the abiotic (i.e., non-living) and biotic (i.e., living) functions, disturbances, or 

events that shape ecosystem patterns. There are physical processes (e.g., fire, hydrologic, geomorphic, 

and climatic regimes; air chemistry, nutrient cycling), biological processes (e.g., competition, predation, 

herbivory, parasitism, disease, migration, dispersal, gene flow, succession, recruitment, maturation), and 

anthropogenic processes (e.g., habitat conversion, novel toxins, vandalism).

ELECTRICAL ENERGY

Electrical energy is the generation or use of electrical power over a period, usually expressed in 

megawatt-hours (MWh), kilowatt-hours (kWh), or gigawatt-hours (GWh).

EXTIRPATED SPECIES

An extirpated species is one that no longer occurs (i.e., has become extinct) in a particular area. Examples 

from the CRE include river otter and razorback sucker.

INVASIVE SPECIES

An invasive species is one that has invaded an area following changes in one or more ecosystem 

processes and has become dominant. Examples from the CRE include non-native species (e.g., tamarisk) 

and native species (e.g., willow). 
Glossary

Attach_04 Page 23 of 24

LEGAL FLEXIBILITY

Legal flexibility is that which is allowed by the legal sideboards statutes, judicial decrees, compacts, and 

treaties controlling operation of the dam.

MONITORING

Monitoring is the “collection and analysis of repeated observations or measurements to evaluate changes 

in condition and progress toward meeting a management objective.”(4) Monitoring needs to produce data 

of sufficient statistical power to detect a trend if in fact it is occurring.(8) Monitoring differs from 

inventorying, which is the measurement of environmental attributes at a given point in time to determine 

what is there. It also differs from research, which is the measurement of environmental attributes to test a 

specific hypothesis.

NATIVE SPECIES

A native species is one that occurred in an area prior to anthropogenic alterations to ecosystem patterns 

and/or processes. Examples from the CRE include humpback chub, razorback sucker, flannelmouth 

sucker, bluehead sucker, speckled dace, Colorado pikeminnow, bonytail, roundtail chub, river otter, 

Kanab ambersnail, Southwest willow flycatcher, brown-headed cowbird, netleaf hackberry, honey 

mesquite & catclaw acacia.

NATURALIZED SPECIES

A naturalized species is one a non-native species that has become established in an area. See examples in 

the CRE listed under non-native species.

NON-NATIVE SPECIES

A non-native species is one that did not occur in an area prior to anthropogenic alterations to ecosystem 

patterns and/or processes. Non-natives are also known as introduced, exotic, or alien species. Many, but 

not all, non-native species can be categorized as an invasive species. Examples of non-native species in 

the CRE include Gammarus, rainbow trout, brown trout, common carp, red shiner, channel catfish, 

tamarisk, and camelthorn.

OPERATIONAL FLEXIBILITY

Operational flexibility is the physical capability of the dam to release water.

QUALITATIVE TARGET

An articulation of the purpose of one or more Management Objectives, in order to give a description in 

words of what the numerical target levels are intended to accomplish and to give direction and guidance 

to the persons who developed the quantitative targets.

RANGE OF NATURAL VARIABILITY

The Range of Natural Variability is the spatial and temporal variation in ecosystem patterns and 

ecosystem processes under which the ecosystem has evolved. The range of natural variability for 

ecological processes is usually defined by their frequency (e.g., number/year), intensity (e.g., cubic feet 

per second), duration (e.g., number of days), magnitude (e.g., acres), seasonally, and rate of change. See 

Landres(18) for a full discussion.

REASONABLE AND PRUDENT ALTERNATIVE

“Reasonable and prudent alternatives refer to alternative actions identified during formal consultation that 

can be implemented in a manner consistent with the intended purpose of the action, that can be 

implemented consistent with the scope of the Federal agency's legal authority and jurisdiction, that is 

economically and technologically feasible, and that the Director believes would avoid the likelihood of 
Glossary

Attach_04 Page 24 of 24

jeopardizing the continued existence of listed species or resulting in the destruction or adverse 

modification of critical habitat.”(5)

REASONABLE AND PRUDENT MEASURE

“Reasonable and prudent measures refer to those actions the Director believes necessary or appropriate to 

minimize the impacts, i.e., amount or extent of incidental take.”(5)

RECOVERY

Recovery is improvement in the status of a listed species to the point at which listing is no longer 

appropriate, under the criteria set out in section 4(a)(1) of the Endangered Species Act (5).

RECREATIONAL GOALS

Recreational goals include Goal 4 (trout) and Goal 9 (recreation).

REMOVAL OF JEOPARDY

To “jeopardize the continued existence of [a listed species] means to engage in an action that reasonably 

would be expected, directly or indirectly, to reduce appreciably the likelihood of both the survival and 

recovery of a listed species in the wild by reducing the reproduction, numbers, or distribution of that 

species.”(5) Removing (or avoiding) jeopardy is intended to be accomplished through the implementation 

of reasonable and prudent alternatives. 

RIPARIAN ECOSYSTEM

The riparian ecosystem is the streamside zone that is influenced by riverine processes, e.g., flood regime 

and distance to subsurface water. 

RIVERINE ECOSYSTEM

The riverine ecosystem is any area typically inundated by the river. 

VIABLE POPULATION

A population is considered viable when there is a high chance of persistence over a long timeframe 

without demographic or genetic augmentation. Population viability is not the same as “recovery” or 

“removal of jeopardy” for a species. However, the concept of population viability is an important 

consideration in determining recovery and removal of jeopardy.