GLOSSARY 

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

The legal definition of Area of Potential Effect is the geographic area or areas within which an

undertaking may cause changes in the character or use of historic properties, if any such 

properties exist (36 CFR 800.2(c)). The Programmatic Agreement signatories are currently (as of 

July 2001) re-evaluating the APE for the Adaptive Management Program and may change it from 

the current 256,000 cfs. 

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...” (on, E.O. 1992. The diversity of life. 

Belknap Press of Harvard University Press, Cambridge, MA 

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). 

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 area where 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). 

CRITICAL REACHES

Critical reaches are where there are only very few, very small, or very high use campsites. These 

reaches are river mile (RM) 6 to 41, RM 75 to 114, RM 130 to 165, and perhaps RM 216 to 246. 

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

definition under Section 101(d)(6)(A) of NHPA. 

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ECOSYSTEM

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

ecological unit.” (Lincoln, R., et al. 1998. A dictionary of ecology, evolution and systematics. 

Cambridge University Press, Cambridge.) An ecosystem consists of patterns and processes that 

are dynamic and occur within a particular range of temporal and spatial variability. 

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.” (Interagency 

Ecosystem Management Task Force. 1995. The ecosystem approach: healthy ecosystems and 

sustainable economies. National Technical Information Service) 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). 

EMERGENCY EXCEPTION CRITERIA

Emergency exception criteria are operating criteria that allow the Western Area Power 

Administration to depart from ROD operating criteria in response to various emergency situations 

in accordance with their obligations to the North American Electric Reliability Council. These 

criteria also provide for exceptions to the ROD criteria during search and rescue situations, 

special studies and monitoring, and dam and powerplant maintenance. 

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 roundtail chub, bonytail chub, and Colorado pikeminnow. 

FINANCIAL EXCEPTION CRITERIA

Financial exception criteria would allow a temporary departure from ROD operating constraints on 

dam releases, as a response to a regional electricity market that is extraordinarily expensive. 

These criteria do not exist at this time. Similar criteria were in place during the period of Interim 

Flows (August 1991 to October 1996). 

FLUVIAL WETLAND (MARSH) COMMUNITY

The vegetation in this community type is composed mainly of herbaceous plants such as cattail

(Typha spp.), bulrush (Scirpus spp.), and common reed (Phragmites australis). This community 

became established at low elevations within the sand beach community following closure of Glen 

Canyon Dam. Currently, it usually occurs between about 8000 and 25,000 cfs in periodically 

inundated environments such as return current channels. 

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INTERESTED PARTY (PER NHPA) 

Interested parties, for purposes of the National Historic Preservation Act, are additional consulting 

parties. Certain individuals and organizations with a demonstrated interest in the undertaking

may participate as consulting parties due to the nature of their legal or economic relation to the 

undertaking or affected properties, or their concern with the undertaking's effects on historic 

properties. 

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). 

MONITORING

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

changes in condition and progress toward meeting a management objective.” (Elzinga, C.L., et

al. 1998. Measuring and monitoring plant populations. BLM) Monitoring needs to produce data of 

sufficient statistical power to detect a trend if in fact it is occurring. (Gibbs, J.P., et al. 1998. 

Monitoring populations of plants and animals. BioScience 48: 935-940.) 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 before 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.

NEW HIGH WATER ZONE COMMUNITY

The vegetation in this community type is dominated by tamarisk (Tamarix ramosissima). Other 

woody plants include coyote willow (Salix exigua), arrowweed (Tessaria sericea), and seepwillow 

(Baccharis spp.). In addition to tamarisk, non-native species include camelthorn (Alhagi 

camelorum), and red brome (Bromus rubens). This community became established mainly at low 

to mid elevations within the sand beach community following closure of Glen Canyon Dam. 

Currently, it usually occurs between about 18,000 and 45,000 cfs. 

NON-NATIVE SPECIES

A non-native species is one that did not occur in an area before 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. 

OLD HIGH WATER ZONE COMMUNITY 

The vegetation in this community type is dominated by Apache plume (Fallugia paradoxa

upstream of river mile (RM) 40, and catclaw acacia (Acacia greggii) downstream of RM 40. 

Mesquite (Prosopis glandulosa) is co-dominant with catclaw acacia between RM 40-77 and RM 

167-225. Other woody plants include redbud (Cercis occidentalis), and netleaf hackberry (Celtis 

reticulata). This community currently occurs on pre-dam flood terraces, sand dunes, and 

stabilized talus slopes above the pre-dam scour zone (about 100,000 cfs stage elevation) and

below desert vegetation. 

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 

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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 (. Landres, P.B., et al. 1999. Overview of the use of natural 

variability concepts in managing ecological systems. Ecological Applications 9: 1179-1188.) 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 jeopardizing the continued existence of listed species or resulting in 

the destruction or adverse modification of critical habitat.” (Fish and Wildlife Service and National 

Oceanic and Atmospheric Administration. 1986. Interagency cooperation - Endangered Species 

Act of 1973, as amended; final rule, June 3. Federal Register 51: 19926-19963.) 

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.” (Fish and Wildlife 

Service and National Oceanic and Atmospheric Administration. 1986. Interagency cooperation - 

Endangered Species Act of 1973, as amended; final rule, June 3. Federal Register 51: 19926-

19963.) 

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. (Fish 

and Wildlife Service and National Oceanic and Atmospheric Administration. 1986. Interagency 

cooperation - Endangered Species Act of 1973, as amended; final rule, June 3. Federal Register

51: 19926-19963.) 

RECREATIONAL GOALS

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

REGULATION

Western operates two load control areas that are tied to GCD. A load control area is a specific

geographic areas assigned to an operator to regulate the moment-by-moment changes in 

electrical demand on the transmission lines in the area. Regulation is the adjustment in electrical 

generation within a load control area to meet minor changes in electrical use as reflected by 

electrical readings on transmission lines. Currently, GCD is committed to providing regulation up 

to plus or minus 1,000 cfs on an instantaneous basis to Western’s load control area. 

REGULATION FOR OTHERS

Regulation for others is that which can be made available for other electrical utilities, provided

they have an electrical transmission link to GCD and that they are a control area operator or have 

contracted an agreement with their control area operator to receive this service. 

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.” (Fish and Wildlife Service and National Oceanic and Atmospheric 

Administration. 1986. Interagency cooperation - Endangered Species Act of 1973, as amended; 

final rule, June 3. Federal Register 51: 19926-19963) Removing (or avoiding) jeopardy is 

intended to be accomplished through the implementation of reasonable and prudent alternatives. 

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RIPARIAN ZONE

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

regime and distance to subsurface water. 

SAND BEACH COMMUNITY

The sparse vegetation in this community type is dominated by Indian ricegrass (Oryzopsis 

hymenoides), beavertail (Opuntia basilaris), four-wing saltbush (Atriplex canescens), and 

ephemeral species that are adapted to frequent floods and scour events. This community has 

been invaded with non-native species such as camelthorn (Alhagi camelorum), Russian thistle 

(Salsola iberica), and red brome (Bromus rubens). Although this community occurs in the predam scour zone (below about 100,000 cfs), willows and other woody species became established 

in some reaches of lower Grand Canyon. 

SEEP AND SPRING COMMUNITIES

The vegetation in this community type is composed of a large array of herbaceous and woody 

species including maidenhair fern (Adiantum capillus-veneris), crimson monkey-flower (Mimulus 

cardinalis), golden columbine (Aquilegia chrysantha), common reed (Phragmites australis), 

Fremont cottonwood (Populus fremontii), poison ivy (Toxicodendron radicans), and birchleaf 

buckthorn (Rhamnus betulaefolia). The water source for these communities can include both 

groundwater and surface water. 

TRIBAL CONSULTATION

Tribal consultation in the AMP is defined as the formal dialogue with designated governmental 

representatives and other AMWG members, through AMWG and TWG meetings, about trust 

assets, resources, and other tribal interests, that results in all the members of the AMWG 

understanding and appreciating tribal perspectives and the inclusion of tribal values within the

AMP. Additionally, this consultation assists federal agencies in realizing their trust responsibility 

to tribal nations and fulfills the federal government’s consultation requirements. Such 

consultation and the subsequent inclusion of tribal values can add to the knowledge base of the 

AMP, and tribal perspectives and values can temper the traditional western scientific approach 

used by the AMP, thus making it stronger. 

TRIBAL PARTICIPATION

Tribal participation ensures that tribal values inform the interpretation of the quantity and quality of 

resources that results from a Western scientific approach to monitoring and research. Tribal 

participation is defined as a set of activities that may include one or more of the following: 

conducting and/or collaborating in resource projects awarded through the competitive process,

participating in discussions with PIs regarding where and how they will conduct monitoring and 

research activities, and tribally relevant data analysis and information sharing. 

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. 

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