(DRAFT – Version 2.0 – 3/02/01) 1

AMP Narrative of Desired Future Resource Conditions

Introduction 

The strategic plan for the Glen Canyon Dam Adaptive Management Program 

(AMP) is based on the premise that key elements of natural ecological processes can, to a 

sufficient degree, be simulated by management actions to achieve desired future resource 

conditions for the Colorado River ecosystem (CRE)1. In addition, the principles 

developed by the Adaptive Management Work Group (AMWG) explicitly recognize that 

Glen Canyon Dam and its provision of water and power resources are an integral part of 

this ecosystem. The operation of Glen Canyon Dam has altered the natural processes and 

habitat that support the natural, physical, and cultural resources of the CRE. 

The biological and physical attributes of the river prior to dam construction, 

introductions of nonnative plants and fish, and other recent human alterations represent 

the conditions under which the natural, physical, and cultural resources in the CRE 

developed. The AMP seeks to return resource conditions of the CREto a more natural 

state. It is assumed that management actions that restore elements of these conditions, 

consistent with the Grand Canyon Protection Act, “Law of the River,” NPS Organic Act 

(and amending legislation), the operational flexibility of the dam, and other guiding legal 

imperatives, will improve conditions of the CRE. 

The AMP desired future resource condition for the CRE centers on maintaining 

viable populations and communities of native plants and animals while retaining valued 

components of the post-dam system. We desire a CRE, including the dam and humans,

that is dynamic in nature and is temporally punctuated by flow events such as BHBFs, 

HMFs, LSSFs, daily/monthly hydropower operations, and tributary flows. Adaptation to 

these events (i.e., disturbance regimes), will predominately influence the structure and 

composition of the plant and animal communities within the CRE, as well as recreational 

quality and the protection of cultural values within the corridor. Thus individual 

 

1

 The Colorado River ecosystem is defined as 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, a 

distance of approximately 293 river miles (Figure 1).
(DRAFT – Version 2.0 – 3/02/01) 2

resources will vary both spatially, depending on their location in the CRE, and temporally 

depending on the nature (i.e., timing, magnitude, duration, periodicity) of the event. See 

Figure ? for a portrayal of these temporal effects. The desired future resource conditions 

described below represent the AMP vision for what will result from successful 

implementation of the AMP strategic plan.

Desired Future Aquatic Resource Conditions

We envision a system where ROD flows significantly increase the productivity of 

the aquatic environment, maintaining the nature of the aquatic plant and invertebrate food 

base to the benefit of naturally reproducing rainbow trout in the Lees Ferry reach and 

native fish throughout the CRE. Viability of native fish populations is not constrained or 

threatened by non-native predation or competition. Except for the Lees Ferry population 

of rainbow trout, positive efforts continue to control numbers of non-native fish. Below 

the Paria River, the Colorado and its tributaries support a community of viable, selfsustaining, native fish populations that benefit from purposeful variations in dam 

releases. The ROD tests both flow and temperature variables in the determination of the 

full extent to which the Dam can continue to be used as a tool to manage the CRE. 

Water quality varies through time and space dependent upon dam releases and 

tributary flows, greatly influencing the aquatic environment. The most conspicuous 

changes result from sediment-bearing tributaries. The Paria and Little Colorado rivers 

produce major amounts of fine sediments during floods. Other ungaged tributaries, with 

their sporadic floods, continue to add their sediment contributions to the flow. These fine 

clays, silts, and sands entering the Colorado dramatically alter the character of the CRE 

below the Paria. The native species, adapted to the pre-dam extremes, continue to persist 

and flourish within this dynamic environment. 

This system allows anglers to experience quality fishing, native fish communities 

to remain viable and healthy, and our grandchildren to enjoy the CRE as the experience 

of a lifetime. 
(DRAFT – Version 2.0 – 3/02/01) 3

Desired Future Riparian Resource Conditions

We envision a resource that varies longitudinally and temporally down river in 

response to substrate geomorphology, water availability, climate and the disturbance 

regime. System disturbance is largely controlled flooding by the operations of Glen 

Canyon Dam. Managed floods are triggered if sufficient sand is available for 

redeposition. Such flooding within the CRE preserves the variability of system 

disturbance and supports native plant and animal communities and their habitats.

The natural communities native to the Grand Canyon dominate the riparian 

ecosystem. The area above the high-water line of major floods supports native riparian 

communities dominated by Apache plume above river mile 40, and mesquite-acacia 

below river mile 40. Below the high-water line, broad sand beaches sparsely vegetated 

with native herbaceous species dominate the scour zone. 

The frequency associated with the presence/absence (coming or going) of riparian 

features, such as ephemeral communities is directly correlated with the frequency of 

flood events. As large flows reset the system and force plant communities back to earlier 

successional stages, a patchwork mosaic of open beaches and vegetated zones is created. 

There is a dynamic mix of both pre- and post-dam riparian communities, such as the old 

high-water zone (OHWZ), new high-water zone (NHWZ), and bare sand beaches and 

marshes. Managed beach/habitat-building flows (BHBFs) enhance the OHWZ 

community species and bare sand beaches. In years without flood disturbance, the 

NHWZ community and marshes flourish. (See Figure ? for a diagram of how the channel

cross section might change with time). 

Non-native species, where present, are not dominant, and do not impair the 

abundance, composition, and distribution of natural communities nor alter the natural 

processes that shape these communities. However, aggressive management action may 

have been used to accomplish this.

The vertebrates native to the CRE dominate the ecosystem. Native species 

resident to the CRE exist as viable populations. The natural processes imposed by 

species that were transient to the CRE, then extirpated, are mimicked by the creation of 

small resident populations or other management actions. 
(DRAFT – Version 2.0 – 3/02/01) 4

As dynamic riparian communities change, we continually assess our protection of 

endangered species from the perspective of threshold levels of habitat that will not 

jeopardize the future existence of the species.

Desired Future Cultural Resource Conditions

The future for cultural resources affected by Glen Canyon Dam operations 

envisions these resources preserved, protected, and interpreted where feasible; and all 

future resource management activities and decisions based on principles of stewardship, 

accountability, consultation, and public education and outreach. All sites unaffected by 

dam operations are left to the natural processes of erosion and deposition.

Desired Future Recreational Resource Conditions 

We envision the CRE with an appropriate spectrum of recreational activities 

within the context of a full wilderness setting. Available activities include hiking, 

fishing, boating and river running, photography, wildlife viewing, etc. Specifically, 

visitor experiences emphasize the appreciation of wilderness values. 

The nature of recreational camping beaches changes from year to year as 

sediment is deposited and eroded. When high runoff years occur, large magnitude 

BHBFs, two or three times power plant capacity, deposit sand high on the banks available 

for visitor use. When low runoff years occur, fall habitat maintenance flows (HMFs) 

redistribute fall tributary sediment inputs above normal, daily power plant releases. 

Recreational activities do not impair the aesthetic, ecological, cultural and 

spiritual values of the Grand Canyon, but provide deep appreciation for these values. 

Visitors accept the river “on its own terms” and celebrate the primitive conditions of one 

of the seven wonders of the world.

Recreational opportunities are enhanced and research activities have minimal 

impact on the CRE. A high value is placed on the extensive wilderness qualities of the 

river corridor. The CRE is remarkable in the length and breadth of its unbroken primitive 

character. It provides unique opportunities for experiencing the natural sounds and 

natural quiet of the desert and river. Opportunities for solitude, connection to nature, and 

personal contemplation outside the trappings of civilization are deeply valued.
(DRAFT – Version 2.0 – 3/02/01) 5

Desired Future Water and Power Resource Conditions

Glen Canyon Dam and the Power Plant continue to operate in a manner consistent 

with the “Law of the River,” including the Grand Canyon Protection Act. The Upper 

Basin States develop their compact allocations of water and deliver water to the Lower 

Basin States as required by compact. The power plant operates to maximize the value of 

the power resource consistent with the resource balancing anticipated in the EIS, ROD, 

and the operating criteria established by the Secretary. Operating criteria continue to be 

modified as the result of long-term monitoring of their effects and further research, 

through the adaptive management process.
N

Scale of Kilometers

0

Ka na b

Creek

Paria

River

Havasu

Creek

Diamond

Cr eek

Peac h

Creek

Lit tle

Colorado

River

Brig ht

Angel Cr.

Crystal Cr.

Clear Cr.

Nankoweap Cr.

Deer Cr.

Tapeats Cr.

 Ferry

Nationa

C

l

anyon

Pearce

UTAH

ARIZONA

NE

VA

D

A

Lake

 Mead

Lake Powell

Glen Canyon Dam

10 0 10 20

Scale of Miles

25 25 50

UTAH

N EWMEXICO

M EXICO

CA LIF OR NIA

ARIZONA

TUCSON

PHOENIX

FLAGSTAFF

AREA OF STUDY

Colorado River

Figure 1. Map of the Geographic Extent of the Colorado River Ecosystem