The State of Natural and Cultural Resources in the Colorado River Ecosystem:
JUNE 30, 1999 DRAFT REPORT
Grand Canyon Monitoring and Research Center
Flagstaff, AZ 86001
Updated: 30 June 1999
Table of Contents
- Executive Summary
- Introduction and Administration
- Physical Resources and Processes: Climate, Hydrology, Sediment
- Water Quality: Lake Powell and the Colorado River Downstream
- Aquatic Biological Resources: Foodbase, Habitat, Native Fish, Non-native Fish
- Terrestrial Biological Resources: Vegetation, Habitat, Wildlife
- Endangered Species and Species of Concern
- Cultural Resources: Archeological Sites; TCP's; Ethonobiology; Havasupai, Hopi, Hualapai, Navajo, Southern Paiute and Zuni Tribes
- Socio-economic Resources: River Running, Angling, Hydropower Production
- Acknowledgements
- Bibliography
- Top of Page
Introduction and Administration
- INTRODUCTION AND ADMINISTRATION
- Administration Overview
- AMWG/TWG and GCMRC
- GCMRC Annual and Strategic Plans
- Administrative History of the Colorado River
- AMWG/TWG and GCMRC
- Study Area Description and Map
- Map of study area
- AMWG
- Vision/Mission, Stakeholder Goals and Management Objectives
- Table of ranked Information Needs and Management Objectives (June 1998)
- Vision/Mission, Stakeholder Goals and Management Objectives
- GCMRC
- Annual and 5-Year Strategic Plans
- Monitoring and Research Activities in 1998-1999
- Conceptual model development
- Protocol and Remote Sensing Review
- Information Management
- Flow and Resource Triggering Criteria for High Flow Events
- Hydrologic flow triggering criteria
- Resource triggering criteria
- Hydrologic flow triggering criteria
INTRODUCTION
Administrative Overview
The Colorado River ecosystem affected by Glen Canyon Dam is the subject of federally authorized monitoring and research to improve ecosystem management in Lake Powell, lower Glen Canyon and throughout Grand Canyon. These scientific studies are coordinated by the Department of the Interior's Grand Canyon Monitoring and Research Center (GCMRC) office in Flagstaff, Arizona, under direction from the Adaptive Management Work Group (AMWG). The AMWG is a Federal Advisory Committee consisting of a diverse group of stakeholders, including: Department of Interior agencies (Bureau of Indian Affairs, Bureau of Reclamation, Fish and Wildlife Service, National Park Service), Western Area Power Administration, Colorado River basin states, Native American tribes, Colorado River Energy Development Association, and environmental organizations. The AMWG meets semiannually to discuss dam management, review the progress of the GCMRC's scientific activities, develop plans for future activities, and provide recommendations to the Secretary of the Interior on Glen Canyon Dam operations. The AMWG is advised by its representatives on the Technical Work Group (TWG).
The wide array of physical, biological and cultural resources and processes of the Colorado River ecosystem are highly dynamic, and some resources respond dramatically to different flow regimes. Effectively managed flow regimes may enhance some resources and ecological processes in this river ecosystem, and a science-based adaptive management process may ensure effective management that optimizes stakeholder concerns while affording appropriate protection of the river ecosystem. Colorado River ecosystem stakeholders have requested from GCMRC an annual scientific evaluation of the state of the ecosystem, and such a report fulfills part of the requirements of the 1992 Grand Canyon Protection Act, as well as some requirements of the 1995 Glen Canyon Dam Environmental Impact Statement (GCD-EIS) and the 1996 Record of Decision (ROD). This evaluation, combined with information on predictions of future reservoir storage and weather, can be used to discuss potential flow regimes to protect and/or enhance development of the Colorado River ecosystem.
This June 1999 State of the Colorado River Ecosystem report provides information on current physical, aquatic biological, terrestrial biological, cultural and socioenconomic resource conditions over time, and especially related to 1996-1999 flows, including the March/April 1996 beach habitat building flow (BHBF), the November 1997 31,000 cfs habitat maintenance flow (HMF), and subsequent flows in 1998 and 1999.
Administrative History of the Colorado River
(Updated from Stevens and Wegner 1995)
- YEAR
- EVENT
- 1902
- Reclamation Act creates the Bureau of Reclamation.
- 1904
- Grand Canyon declared a National Game Reserve (T. Roosevelt).
- 1916
- National Park Service Organic Act.
- 1919
- Grand Canyon declared a national park, stipulating "reclamation projects" within park boundaries.
- 1922
- The Colorado River Compact allocates the river's water between the upper (Wyoming, Colorado, Utah and New Mexico) and lower (Arizona, Nevada and California) basins.
- 1920-25
- U.S. Geological Survey of potential dam sites.
- 1945
- The Mexican Treaty guarantees 1.5 million acre feet of water to Mexico.
- 1948
- The Upper Basin Compact allocates Colorado River water between the upper basin states.
- 1956
- The Colorado River Storage Project (CRSP) Act is passed, authorizing construction of upper basin dams.
- 1957-63
- Glen Canyon Dam construction, power production starts in 1964.
- 1967
- Humpback chub and Colorado pikeminnow listed as endangered.
- 1973
- The National Environmental Policy Act was passed.
- 1976
- The NPS coordinates the first ecological inventory of the Grand Canyon (Carothers and Aitchison 1976), and the first sociological studies.
- 1976
- Last Colorado Pikeminnow caught in Grand Canyon at Havasu Creek.
- 1978
- FWS Jeopardy Opinion on the operation of Glen Canyon Dam.
- 1980
- Lake Powell fills for the first time; bonytail chub listed as endangered.
- 1981-82
- Rewind of Glen Canyon Dam turbines, Bureau of Reclamation states that there will be no significant effect on downstream river ecosystem.
- 1983
- Secretary of the Interior James Watt orders Bureau of Reclamation Glen Canyon Environmental Studies (GCES) Program to study dam impacts; post-dam record 2,724 m3/s flow is released.
- 1983-86
- Forty studies of dam effects conducted during exceptionally high inflow and corresponding downstream releases.
- 1987
- National Academy of Sciences (NAS) review of GCES Phase I (NAS 1987).
- 1988
- Cooperating agencies conclude that GCES Phase I (Bureau of Reclamation 1988) showed: (1) dam affects river ecosystem, but (2) more data needed on low and fluctuating flows to determine how to best manage the system.
- 1989
- Secretary of the Interior Manuel Lujan orders an ex post facto EIS on dam operations; initiation of GCES Phase II to support EIS preparation.
- 1990-91
- Test flows were used to determine effects of individual flow regimes (Patten 1991).
- 1991
- Interim flows (low hourly change in flow) implemented on 1 August to protect river resources while EIS is prepared; interim flows monitoring implemented by Reclamation on 1 August and formalized in November 1991 Santa Fe "State of Knowledge" symposium (NAS 1991); razorback sucker listed as endangered.
- 1992
- NAS "Delphi Process" symposium in Irvine, CA to plan long-term monitoring for the Colorado River corridor. Passage of the Grand Canyon Protection Act provides for a speedy resolution of the EIS and balancing environmental protection with economic benefits.
- 1994
- FWS Biological Opinion concludes that Glen Canyon Dam still jeopardizes native fish.
- 1995
- Final EIS submitted
to Secretary of the Interior Bruce Babbitt, calling for
- low flow fluctuations to preserve tributary derived bed sand,
- planned flooding to restore higher elevation sand bars,
- adaptive management based on
- long-term monitoring and cooperative, interagency discussion.
- 1996
- A Beach Habitat Building Flow (BHBF, experimental flood) was conducted from Glen Canyon Dam from 26 March-2 April. The FWS Biological Opinion on the planned flood restricted take of Kanab ambersnail habitat to <10%, and stipulated that no additional planned high flows be conducted until at least one additional KAS population is discovered or established in Arizona. The Secretary's Record of Decision (ROD) is signed, formalizing the flow regime and adaptive management framework.
- 1997
- GCES is replaced by the Grand Canyon Monitoring and Research Center. Flows (27,000 cfs) above the ROD occurred in February/March, and again in mid-summer. The Adaptative Management Work Group (with the Technical Work Group) formally convened as a Federal Advisory Committee. An experimental Habitat Maintenance Flow was conducted in early November.
- 1998
- BHBF flow triggering criteria formalized by AMWG; El Nino's predicted high snowpack failed to materialize; Lake Powell near full pool (3700') in July.
- 1999
- Inflow and storage conditions in Lake Powell are insufficient to trigger a BHBF from January-June;Lake Powell near full pool (3700') in late June.
STUDY AREA
The Colorado River Ecosystem Affected by Glen Canyon Dam
Fig. IA1.1: Map of the Colorado River ecosystem. Updated 7 December 1998.
Geography and Boundaries
The Colorado River ecosystem considered by the Secretary of the Interior's 1996 Record of Decision encompasses the mainstream river and its floodplain affected by Glen Canyon Dam, from Lake Powell to the western-most boundary of Grand Canyon National Park. In addition, the study area includes Lake Powell (for some characteristics), as well as some aspects of flow, sediment transport, biology and other aspects of some tributaries.
This is a large, dynamic desert river ecosystem, and is an essential water source for much of the Southwest. The Colorado River flows 473 km from Glen Canyon Dam (975 m elevation) to the Grand Wash Cliffs on upper Lake Mead (350 m elevation) through Sonoran and Mohave desert terrain, through lower Glen Canyon and all of Grand Canyon. By convention, locations along the Colorado River are designated in river miles from Lees Ferry. The river passes through 13 bedrock-defined geomorphic reaches, and the Paria (km 1) and Little Colorado (km 98) rivers create three turbidity segments (Schmidt and Graf 1990, Stevens et al. 1997b):
| Segment | Name | Distance | (mi) | Mean Width (ft) |
|---|---|---|---|---|
| 1. CW | Glen Canyon | 15.5 | -0.7 | 518 |
| 2. VT | Permian Gorge | 0.7 | -11.0 | 280 |
| 3. VT | Supai Gorge | 11.0 | - 22.5 | 210 |
| 4. VT | Redwall Gorge | 22.5 | - 40.0 | 220 |
| 5. VT | Marble Canyon | 40.0 | -61.5 | 350 |
| 6. UT | Furnace Flats | 61.5 | -77.5 | 390 |
| 7. UT | Upper Granite Gorge | 77.5 | - 117.9 | 190 |
| 8. UT | The Aisles | 117.9 | - 125.5 | 230 |
| 9. UT | Muav Gorge | 125.5 | -139.9 | 210 |
| 10. UT | Lower Canyon Reach | 139.9 | - 159.9 | 180 |
| 11. UT | Lower Canyon Reach | 159.9 | - 213.8 | 310 |
| 12. UT | Lower Granite Gorge | 213.8 | - 240.0 | 240 |
| 13. UT | Upper Lake Mead | 240.0 | 278.0 | 770 |
Table IA1.1: The bedrock- and landform-defined geomorphic reaches of the Colorado River in Grand Canyon. Distance (mi) is measured from Lees Ferry, Arizona which lies 15.5 mi downstream from Glen Canyon Dam. Turbidity segments include the clearwater (CW), variably turbid (VT) and usually turbid (UT) segments. Reach names have been modified from Schmidt and Graf (1990) and reach width (ft) was measured at a mainstream flow of 24,000 cfs by Schmidt and Graf (1990), and by Stevens (1997a) at a comparable flow for reaches 1 and a Lake Mead pool surface elevation of 1200'.
Unlike large unconstrained rivers with broad floodplains, the Colorado River in Glen and Grand canyons is confined by talus slopes and bedrock geology to a relatively narrow channel. Debris flows have reached the river at the mouths of more than 600 tributaries in this system, creating debris fan constrictions and eddies that control where sand and finer grain alluvial sediments can deposit, and dictating the location of sand deposits. Unlike the Mississippi River, sand bars in the Grand Canyon are geomorphically fixed and do not move. These debris fan-eddy complexes are distinctive, repeated geomorphic units separated by relatively uniform runs of channel. Sand deposits and debris fans support distinctive vegetation assemblages that, in turn, provide food and habitat for fish and wildlife. Thus, the Colorado River ecosystem is structured by geology and hydrology, and is a strongly "bottom-up" ecosystem.
AMWG/TWG (Hyperlink to BOR web pages)
Adaptive Management Work Group Vision/Mission Statement
(Pending approval by AMWG - 23 June 1999)
Stakeholder Goals
(Pending approval of Vision/Mission Statement - 23 June 1999)
Stakeholder Management Objectives
| Resource Category | Short Name | Info Need | Mgt Obj | O | X | Monitor or Resch Status |
|---|---|---|---|---|---|---|
| Ecosystem assessment | Conceptual model | IN 1.1 | MO 1: | 7 | 14 | R |
| Aquatic foodbase | Aquatic foodbase - monitor | IN 1.1 | MO 1: | 10 | 9 | M |
| Aquatic foodbase | Aquatic foodbase - dam FX | IN 1.2 | MO 1: | 10 | 9 | R |
| Aquatic foodbase | Aquatic foodbase for fish | IN 1.3 | MO 1: | 10 | 10 | R |
| Trout | Trout population dynamics | IN 2.1 | MO 2: | 8 | 9 | R |
| Trout | Trout population trends | IN 2.2 | MO 2: | 5 | 5 | M |
| Trout | Trout condition #1 | IN 2.3 | MO 2: | 2 | 1 | M |
| Trout | Trout spawning habitat availability | IN 2.4 | MO 2: | 4 | 4 | R |
| Trout | Trout condition #2 | IN 2.5 | MO 2: | 4 | 0 | M&R |
| Trout | Trout maintenance RX#1 | IN 2.6 | MO 2: | 4 | 3 | R |
| Trout | Trout/foodbase trophic dynamics | IN 2.7 | MO 2: | 3 | 4 | R |
| Native Fish | HBC population dynamics | IN 3/4.1 | MO 3/4: | 10 | 10 | M&R |
| Native Fish | HBC recruitment | IN 3/4.2 | MO 3/4: | 11 | 8 | M&R |
| Native Fish | HBC winter survival | IN 3/4.3 | MO 3/4: | 10 | 8 | R |
| Native Fish | HBC intrxn with NN fish | IN 3/4.4 | MO 3/4: | 2 | 0 | R&M |
| Native Fish | HBC habitat availability | IN 3/4.5 | MO 3/4: | 10 | 6 | R |
| Native Fish | HBC protocol and recreation FX | IN 3/4.6 | MO 3/4: | 2 | 1 | Protocol R |
| Native Fish | HBC trophic dynamics | IN 3/4.7 | MO 3/4: | 7 | 6 | R |
| Native Fish | HBC YOY habitat and NNS interxs | IN 3/4.8 | MO 3/4: | 7 | 6 | R |
| Native Fish | HBC population loss to flows | IN 3/4.9 | MO 3/4: | 6 | 5 | R |
| Native Fish | HBC good year strategy | IN 3/4.10 | MO 3/4: | 4 | 2 | Admin. |
| Native Fish | HBC downstream transport | IN 3/4.11 | MO 3/4: | 6 | 3 | R |
| Native Fish | HBC flow-related take | IN 3/4.12 | MO 3/4: | 9 | 8 | R |
| Native Fish | HBC flow criteria to limit take | IN 3/4.13 | MO 3/4: | 8 | 7 | Admin. |
| Native Fish | Threatened fish - RPM test flows | IN 3/4.14 | MO 3/4: | 5 | 4 | R |
| Native Fish | Native fish - mainstream thermal model | IN 5.1 | MO 5: | 6 | 2 | R |
| Native Fish | Native fish - thermal mod FX#1 | IN 5.2 | MO 5: | 10 | 10 | R |
| Native Fish | Native fish - thermal mod FX#2 | IN 5.3 | MO 5: | 14 | 14 | R |
| Native Fish | Thermal mod impacts on LP fish | IN 5.4 | MO 5: | 7 | 2 | R |
| Native Fish | NN fish control - temperature and floods | IN 5.5 | MO 5: | 9 | 9 | R |
| Native Fish | HBC population mgt. criteria | IN 6.1 | MO 6: | 9 | 8 | R |
| Native Fish | HBC 2nd pop. feasibility study | IN 6.2 | MO 6: | 9 | 7 | R |
| Native Fish | RBS 2nd pop. feasibility study | IN 7.1 | MO 7: | 7 | 5 | R |
| Native Fish | Native fish pop. status | IN 8.1 | MO 8: | 9 | 8 | M |
| Native Fish | Native fish pop. dynamics#1 | IN 8.2 | MO 8: | 7 | 4 | M |
| Native Fish | Native fish historic pop. dynamics #1 | IN 8.3 | MO 8: | 3 | 1 | M&R |
| Native Fish | Native fish historic pop. dynamics#2 | IN 8.4 | MO 8: | 5 | 2 | M&R |
| Native Fish | Native fish flow regime FX | IN 8.5 | MO 8: | 7 | 4 | R |
| Native Fish | Native fish maintenance criteria | IN 8.6 | MO 8: | 7 | 4 | R |
| Native Fish | Native fish experimental flows design #1 | IN 9.1 | MO 9: | 3 | 2 | R |
| Native Fish | Native fish experimental flows design #2 | IN 9.2 | MO 9: | 5 | 1 | R |
| Native Fish | Native fish trib flows and recruitment | IN 9.3 | MO 9: | 7 | 3 | M&R |
| Native Fish | Native - NN fish nearshore intrxns | IN 9.4 | MO 9: | 6 | 1 | R |
| Native Fish | Native/NN fish intrxns #1 | IN 10.1 | MO 10: | 6 | 5 | R |
| Native Fish | Native/NN fish intrxns #2 | IN 10.2 | MO 10: | 4 | 3 | R |
| Native Fish | Native/NN fish mitigation intrxns | IN 10.3 | MO 10: | 3 | 3 | R |
| Native Fish | NN fish distrib. and natural history | IN 10.4 | MO 10: | 5 | 2 | M |
| Native Fish | Native/NN fish intrxns #3 | IN 10.5 | MO 10: | 6 | 2 | R |
| Native Fish | Native and NN fish autecology | IN 10.6 | MO 10: | 6 | 2 | M&R |
| Riparian | Autecology of riparian species | IN 11.1 | MO 11: | 9 | 9 | M&R |
| Riparian | Riparian population variability | IN 11.2 | MO 11: | 4 | 6 | M&R |
| Riparian | Riparian SOC population changes | IN 11.3 | MO 11: | 2 | 4 | M&R |
| Riparian | Riparian species habitat distribution | IN 11.4 | MO 11: | 5 | 7 | M&R |
| Riparian | Riparian habitat map | IN 11.5 | MO 11: | 5 | 4 | R |
| Riparian | Monitor leopard frogs | IN 11.6 | MO 11: | 6 | 8 | R |
| Riparian | Feasibility of 2nd leopard frog populations | IN 11.7 | MO 11: | 1 | 1 | Admin. |
| Riparian | Evaluate amphibian sensitivity | IN 11.8 | MO 11: | 2 | 3 | R |
| Riparian | Riparian spp - dam FX on demography #1 | IN 12.1 | MO 12: | 6 | 8 | R |
| Riparian | Riparian spp - ranges | IN 12.2 | MO 12: | 1 | 1 | R |
| Riparian | Riparian spp - age classes | IN 12.3 | MO 12: | 0 | 0 | R |
| Riparian | Riparian spp - dam FX on demography #2 | IN 12.4 | MO 12: | 2 | 2 | R |
| Riparian | Riparian spp - general dam FX | IN 12.5 | MO 12: | 1 | 1 | R&M |
| Riparian | Riparian food webs: SOC | IN 13.1 | MO 13: | 7 | 7 | R&M |
| Riparian | Riparian food webs: birds | IN 13.2 | MO 13: | 6 | 8 | R |
| Riparian | Pefa - aerie distribution | IN 13.3 | MO 13: | 1 | 1 | R&M |
| Riparian | Pefa - population dynamics | IN 13.4 | MO 13: | 2 | 2 | R |
| Riparian | Bald eagle - dam FX | IN 13.5 | MO 13: | 3 | 3 | R&M |
| Riparian | KAS - habitat RX #1 | IN 14.1 | MO 14: | 9 | 8 | M |
| Riparian | KAS - special flow impacts | IN 14.2 | MO 14: | 7 | 7 | R&M |
| Riparian | KAS - habitat RX #2 | IN 14.3 | MO 14: | 8 | 8 | R&M |
| Riparian | KAS - monitor exceptional flow impacts | IN 14.4 | MO 14: | 7 | 7 | M |
| Riparian | KAS - life history schedule | IN 14.5 | MO 14: | 7 | 7 | R&M |
| Riparian | KAS - monitor #1 | IN 14.6 | MO 14: | 11 | 10 | R&M |
| Riparian | KAS - monitor #2 | IN 14.7 | MO 14: | 5 | 6 | M |
| Riparian | KAS - genetic relationships | IN 15.1 | MO 15: | 7 | 5 | R |
| Riparian | KAS - habitat propagation | IN 15.2 | MO 15: | 6 | 4 | R |
| Riparian | Riparian veg - distribution: all #1 | IN 16.1 | MO 16: | 5 | 6 | M |
| Riparian | Riparian veg - distribution: OHW | IN 16.2 | MO 16: | 4 | 5 | R&M |
| Riparian | Riparian veg - maintain and restore | IN 16.3 | MO 16: | 0 | 0 | M |
| Riparian | Riparian veg - dam FX | IN 16.4 | MO 16: | 4 | 4 | R&M |
| Riparian | Riparian veg - life histories | IN 16.5 | MO 16: | 2 | 2 | R |
| Riparian | Riparian veg - NNS and dam FX | IN 16.6 | MO 16: | 4 | 5 | R&M |
| Cultural | Cultural sites - monitor | IN 1.1 | MO 1: | 12 | 13 | M |
| Cultural | Cultural sites - risk assessment | IN 1.2 | MO 1: | 6 | 4 | R |
| Cultural | Cultural sites - info needs | IN 1.3 | MO 1: | 7 | 7 | Admin. |
| Cultural | Cultural sites - monitor risk | IN 1.4 | MO 1: | 6 | 5 | R&M |
| Cultural | Cultural sites - preserve terraces #1 | IN 1.5 | MO 1: | 5 | 2 | M |
| Cultural | Cultural sites - preserve terraces #2 | IN 1.6 | MO 1: | 6 | 2 | R&M |
| Cultural | Cultural sites & recreation FX | IN 1.7 | MO 1: | 1 | 0 | R |
| Cultural | Cultural sites - mitigation strategies | IN 2.1 | MO 2: | 9 | 9 | Admin. |
| Cultural | Cultural sites - data recovery strategies | IN 2.2 | MO 2: | 5 | 2 | Admin. |
| Cultural | Cultural sites - characterize dam FX | IN 3.1 | MO 3: | 9 | 6 | R |
| Cultural | Cultural site data management | IN 4.1 | MO 4: | 7 | 5 | Admin. |
| Socioeconomic | Socioeconomics - monitor hydropower $ | IN 1.1 | MO 1: | M | ||
| Socioeconomic | Socioeconomics - costs of ROD | IN 1.2 | MO 1: | M | ||
| Socioeconomic | Socioeconomics - research costs | IN 1.3 | MO 1: | M | ||
| Socioeconomic | Socioeconomics - integrated systems mgt. | IN 1.4 | MO 1: | Admin. | ||
| Water | Flow - monitor releases | IN 1.1 | MO 1: | M | ||
| Water | Flow - monitor WQ and dam FX on major ions | IN 2.1 | MO 2: | 9 | 9 | M |
| Water | Flow - thermal modification | IN 2.2 | MO 2: | 6 | 6 | R&M |
| Sediment | Sediment - historic distribution & flow FX: all #1 | IN 1.1 | MO 1: | 5 | 7 | R&M |
| Sediment | Sediment - minimum storage for sustainability | IN 1.2 | MO 1: | 9 | 11 | R |
| Sediment | Sediment - monitor flow FX by reach | IN 1.3 | MO 1: | 7 | 10 | R |
| Sediment | Sediment - monitor inputs: all | IN 1.4 | MO 1: | 8 | 10 | R&M |
| Sediment | Sediment - GCNRA bar distribution, sand input | IN 1.5 | MO 1: | 5 | 6 | R&M |
| Sediment | Sediment - bar & backwater distribution: '90-91 | IN 2.1 | MO 2: | 1 | 1 | M |
| Sediment | Sediment - establish baselines | IN 2.2 | MO 2: | 3 | 2 | Admin. |
| Sediment | Sediment - monitor sand bar distribution #1 | IN 2.3 | MO 2: | 3 | 5 | R&M |
| Sediment | Cultural - monitor terraces | IN 2.4 | MO 2: | 2 | 3 | M |
| Sediment | Sediment - bar & backwater distribution: model | IN 2.5 | MO 2: | 3 | 3 | R&M |
| Sediment | Sediment - bar, backwater and camp distribution | IN 2.6 | MO 2: | 6 | 8 | R&M |
| Sediment | Sediment - bar & backwater distribution | IN 2.7 | MO 2: | 2 | 5 | R |
| Sediment | Flow - spillway impacts on bed and benthos | IN 2.8 | MO 2: | 1 | 1 | R&M |
| Sediment | Backwater distribution: '90-91, 96-97 #1 | IN 3.1 | MO 3: | 4 | 3 | R |
| Sediment | Backwater distribution: '90-91, 96-97 #2 | IN 3.2 | MO 3: | 3 | 2 | R |
| Sediment | Sediment - bar & backwater distribution #2 | IN 3.3 | MO 3: | 3 | 4 | R&M |
| Sediment | Sediment - linkage to biota | IN 3.4 | MO 3: | 7 | 8 | R |
| Sediment | Backwater distribution: '90-91, 96-97 #3 | IN 3.5 | MO 3: | 2 | 3 | R |
| Sediment | Backwater distribution: '90-91, 96-97 #4 | IN 4.1 | MO 4: | 6 | 6 | R&M |
| Sediment | Sediment - model dam FX on bars, backwaters | IN 4.2 | MO 4: | 4 | 6 | Admin. |
| Sediment | Sediment - assess dam FX on bars, backwaters | IN 4.3 | MO 4: | 5 | 5 | Admin. |
| Sediment | Sediment - monitor inputs: Marble Canyon | IN NH1. | MO 4: | 3 | 3 | R&M |
| Sediment | Sediment - GCNRA high terrace erosion #1 | IN NH2. | MO 4: | 1 | 1 | R |
| Sediment | Sediment - monitor inputs: GCNRA | IN NH3. | MO 4: | 2 | 2 | R |
| Sediment | Sediment - GCNRA high terrace erosion #2 | IN NH4. | MO 4: | 2 | 1 | R&M |
| Sediment | Sediment - GCNRA bed morphology dynamics | IN NH5. | MO 4: | 2 | 4 | R |
| Sediment | Sediment - GCNRA grain size distribution | IN NH6. | MO 4: | 1 | 1 | R |
| Sediment | Sediment - historic distribution & flow FX: GCNRA | IN NH7. | MO 4: | 0 | 2 | R&M |
| Sediment | Sediment - historic distribution & flow FX: all #2 | IN NH8. | MO 4: | 2 | 3 | R&M |
| GIS | GIS - map topography, geology, soils | IN 1.1 | MO 1: | 1 | 1 | R |
| GIS | GIS - data archival and storage | IN 1.2 | MO 1: | 0 | 2 | Admin. |
| Recreation | Recreation - experience | IN 1.1 | MO 1: | 4 | 9 | R&M |
| Recreation | Recreation - monitoring and research impacts | IN 1.2 | MO 1: | 2 | 5 | R |
| Recreation | Recreation - mitigate negative flow FX | IN 1.3 | MO 1: | 4 | 10 | Admin. |
| Recreation | Recreation - angler satisfaction, use and harvest | IN 1.4 | MO 1: | 2 | 3 | R&M |
| Recreation | Water - heavy metal impacts on fish | IN 1.5 | MO 1: | 0 | 0 | R |
| Recreation | Recreation - camp distribution,carrying capacity | IN 2.1 | MO 2: | 1 | 10 | R&M |
| Recreation | Recreation - dam FX on camp distribution | IN 2.2 | MO 2: | 6 | 8 | Admin. |
| Recreation | Recreation - develop campsite monitoring strategy | IN 2.3 | MO 2: | 1 | 3 | Admin. |
| Recreation | Recreation - model flow FX on campsites | IN 2.4 | MO 2: | 2 | 2 | R |
| Recreation | Recreation safety - boating: GCNRA | IN 3.1 | MO 3: | 1 | 3 | R&M |
| Recreation | Recreation safety - boating: all | IN 3.2 | MO 3: | 3 | 3 | R&M |
| Recreation | Recreation safety - boating: Grand Canyon | IN 3.3 | MO 3: | 2 | 1 | R&M |
| Recreation | Ecosystem Assessment - FX of flows for safety on ecosystem | IN 3.4 | MO 3: | 1 | 0 | Admin. |
| Recreation | Recreation - Resource conflicts with day rafting | IN 3.5 | MO 3: | 2 | 1 | Admin. |
| Recreation | Trout - flows RX for 100k trout | IN 4.1 | MO 4: | 2 | 7 | R |
| Recreation | Waterfowl - hunter use, satisfaction, conflicts | IN 5.1 | MO 5: | 1 | 2 | R |
| Lake Powell | Water - Lake Powell WQ | IN 1.1 (Phys) | MO 1: | 10 | 14 | R&M |
| Lake Powell | Water - dam FX on Lake Powell WQ &productivity | IN 1.1 (Biol) | MO 1: | 5 | 12 | R |
| Lake Powell | Water - Lake Powell, selenium impacts #1 | IN 1.2 | MO 1: | 1 | 0 | R |
| Lake Powell | Water - water temperature impacts in Lake Powell | IN 2.1 | MO 2: | 1 | 9 | R |
| Lake Powell | Lake Powell - dam FX on surface flux impacts | IN 2.2 | MO 2: | 0 | 1 | R&M |
| Lake Powell | Water - Lake Powell, selenium impacts #2 | IN 2.3 | MO 2: | 0 | 0 | R |
| Lake Powell | Lake Powell - dam FX on advective flow | IN 2.4 | MO 2: | 0 | 1 | R&M |
| Lake Powell | Lake Powell - fish: dam FX on pred-prey rels. | IN 2.5 | MO 2: | 1 | 1 | R |
| Lake Powell | Lake Powell - fish: dam FX on movement | IN 2.6 | MO 2: | 1 | 5 | R |
| Aquatic foodbase | Fisheries - habitat distribution: mainstream+ tribs | IN 1.7 (App.) | MO 1: | 1 | 3 | R |
| Aquatic foodbase | GIS - aquatic habitat map by stage | IN 1.8 (App.) | MO 1: | 1 | 1 | R |
| Aquatic foodbase | Fisheries - dam FX on habitat distribution | IN 1.9 (App.) | MO 1: | 2 | 4 | R |
| Aquatic foodbase | Aquatic foodbase - exposure FX | IN 1.10 (App.) | MO 1: | 2 | 3 | R |
| Aquatic foodbase | Aquatic foodbase - dam FX on hyporheic comms. | IN 1.11 (App.) | MO 1: | 0 | 0 | R |
| Aquatic foodbase | Water - selenium impacts on benthos/hyporheic | IN 1.12 (App.) | MO 1: | 1 | 0 | R |
| Native fish | FMS spawning hab. distrib. #1: recruitment | IN 1. (App.) | MO 8: | 3 | 1 | R&M |
| Native fish | FMS adult origins | IN 2. (App.) | MO 8: | 2 | 2 | R&M |
| Native fish | FMS spawning hab. distrib. #2: Glen Canyon | IN 3. (App.) | MO 8: | 3 | 1 | R&M |
| Native fish | FMS mechanisms of spawning failure | IN 4. (App.) | MO 8: | 2 | 1 | R |
| Native fish | Native fish - FMS dam FX on recruitment | IN 5. (App.) | MO 8: | 3 | 2 | R |
| Native fish | Native fish - spawning and trib. Mouths | IN 6. (App.) | MO 8: | 2 | 1 | R&M |
| Native fish | Aquatic foodbase - dam FX on distribution | IN 7. (App.) | MO 8: | 0 | 0 | R&M |
| Native fish | Native fish - FMS habitat RX | IN 8. (App.) | MO 8: | 1 | 0 | R |
| Native fish | Native fish - FMS spawning hab. distrib. #3: site fidelity | IN 9. (App.) | MO 8: | 1 | 0 | R&M |
| Native fish | Native fish - MS spawning hab. Distrib. #4: historic use | IN 10. (App.) | MO 8: | 0 | 0 | R&M |
| Native fish | Native fish - FMS population model | IN 11. (App.) | MO 8: | 2 | 1 | R |
| Native fish | Native fish - FMS habitat modification RX | IN 12. (App.) | MO 8: | 1 | 0 | Admin. |
| Native fish | Native/NN fish intrxns #4 | IN 13. (App.) | MO 8: | 2 | 0 | R |
| Native fish | Water - selenium FX on native fish | IN 14. (App.) | MO 8: | 0 | 0 | R |
Table IA 1.1: AMWG stakeholder management objectives (revised June 1998). These management objectives (MO's) and information needs (IN's) were prioritized: "O" category represented a general vote on the importance of the category, with a maximum score of 14; "X" category represented a ranking vote within a resource topic of individual IN or MO importance. The status of IN's and MO's were categorized by GCMRC as being monitoring, research, protocol assessment, or administrative in nature.
Protocol and Remote Sensing Review
Hydrologic and Resource Triggering Criteria for High Flow Events
Physical Criteria for Triggering High Releases
An Analysis of the Monthly Release Volumes
Temporally Adjacent to a Beach Habitat Building Flow
Triggered by the Recently Developed Triggering Criteria
Updated by Randall Peterson on February 10, 1998
Background
When the 1996 Annual Operating Plan was issued containing the agreement between the Secretary of the Interior and the Basin States regarding Beach/Habitat Building Flows (BHBF=s), there were some concerns about the magnitude of monthly release volumes during other months in years when BHBF=s would occur. The greatest concern focused on potential sediment transport and the erosion of beach deposits, particularly if flows in the months following a BHBF were near powerplant capacity (~33,200 cfs).
During the last few months, as the triggering criteria were developed to completely define the 1996 agreement, all parties involved attempted to define criteria that reflected a reasonable risk or certainty that a spill would occur later in the spring. Under this criteria, when the reservoir was at its target storage level of 21.5 MAF on January 1 there is about a 1 in 3 chance of a BHBF being triggered sometime between January and June. This report analyzes both the monthly releases expected to occur at the time such a BHBF was triggered and the monthly releases that actually occurred.
Expected Releases
In order to achieve a reasonable level of risk of a spring spill, the subgroup believed a BHBF would need to be triggered prior to the scheduling of maximum powerplant releases for the remainder of the runoff season, i.e., before a spring spill became an absolute certainty. With Reclamation=s monthly release scheduling philosophy, releases have been aggressively increased when there is a high potential for a spring spill. Therefore, if an inflow forecast were to indicate the potential for high releases to avoid spills, releases during the current month would likely be at 25,000 cfs or greater even though future months may only have 20,000 cfs scheduled. Such practice reflects this aggressive spill avoidance and results in the current frequency of actual spills every 1 in 10 years on average. Less aggressive release patterns would result in a greater frequency of uncontrolled spring spills. However, the desire to limit sediment transporting flows to less than 25,000 cfs moderates to some degree the desire to avoid spills in all situations.
When the BHBF subgroup worked to develop BHBF criteria, it modeled releases using a more moderate release philosophy, trying to keep the monthly release volumes less than 1.5 MAF until the risk of an uncontrolled spring spill became unreasonably large, but at the same time trying to avoid anticipated spills. Table 1 lists the 10 modeled years when BHBF=s would have been released, under the assumption of a January 1 Lake Powell storage content of 21.5 MAF. The boxed numbers are the month in which the BHBF would have occurred. The top half of Table 1 shows that the average monthly release volume from the time a BHBF was triggered though the month of July was expected to be 1.35 MAF (about 22,500 cfs) at the time a BHBF was triggered. If the extreme years of 1983 and 1984 and the high forecast error year of 1995 were excluded, the average monthly release was expected to be 1.30 MAF (about 21,700 cfs).
Actual Releases
The bottom half of Table 1 shows these actual releases for the 10 BHBF years modeled by the subteam. In 90 percent of these modeled cases the actual ex post facto release volumes during these BHBF years were greater than was expected when the BHBF occurred. This is likely a result of forecasting procedures that tend to underforecast high runoff years; therefore, BHBF years have a tendency to have higher than expected releases after the BHBF occurred. This is further validation that the triggering criteria recommended by the AMWG properly identifies a significant risk level of uncontrolled spills. Despite the fact that future releases are not expected to be at powerplant capacity when a BHBF occurred, subsequent actual releases are higher than expected as a result of increases in the forecasted spring runoff and an increased risk of uncontrolled spills.
From Table 1, the actual average monthly releases through July following BHBF=s were 1.64 MAF (about 27,300 cfs). Excluding the high flood and forecast error years of 1983, 1984, and 1995 the average is 1.46 MAF (about 24,300 cfs). Of the total months through July following a BHBF, 83 percent had release volumes greater than 1.2 MAF (about 20,000 cfs) and 46 percent had release volumes greater than 1.5 MAF (about 25,000 cfs).
Table 1
Resource Criteria Triggering High Flows -- .pdf format (31.9 KB)
(B. Ralston, B. Gold, and R. Winfree).