According to the report, water management has altered the natural state of the river, including the long-term presence of major dams and non-native species, and changes in water flow in the system.
National parks examined in the study include Grand Canyon National Park, Glen Canyon National Recreation Area, Canyonlands National Park, Dinosaur National Monument, and Black Canyon of the Gunnison National Park.
The report cites several factors which affect the rivers in these parks:
- Dams along the Colorado River have fundamentally changed ecological and environmental processes in these parks by destroying natural habitats in some areas, creating highly unnatural flow regimes, trapping sediments that are critical for building and maintaining aquatic and riparian habitats and altering natural water temperatures that foster native fish communities.
- Reintroducing more natural water flows in the rivers can protect park resources. In addition, any further alterations to the natural flow of the river must not compromise these treasured parks, which receive a total of more than 8.5 visitors annually. . Recent proposals to divert water from the River for municipal and agricultural uses would likely be detrimental to the parks.
- Climate change scenarios predict the western United States will become drier and warmer, which increases the likelihood that the volume of water in the river annually will decrease and releases from reservoirs like Lake Powell will be reduced.
- Non-native fish have been introduced; causing issues for native species through predatory and competitive behavior and the non-native tamarisk has altered the river channel, further restricting river flows.
The report outlines steps that can be taken to reverse or mitigate some of the challenges facing the river, including:
- Changes to dam operations to reduce impacts on endangered species and other resources, which would have relatively minor effects on hydropower revenues.
- Climate change research to clearly understand and ensure that its effects on the River are taken into account for all future policies and decisions impacting water flow in the river.
- Additional research on costs and benefits of restoring more natural flows so that the value of the parks along the River can be properly assessed.
To view a full copy of the report, please visit: http://www.npca.org/cpr/colorado_river_basin/
source: National Parks Conservation Association