Restoration: Grand Canyon controlled floods effects are short-lived, the river requires constant attention

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From the Arizona Republic via Arizona Central:

One of the lessons of the first three floods was that the effects are short-lived. The river requires constant attention, with more-frequent floods and monitoring, said Martha Hahn, chief of science and resource management at Grand Canyon National Park. “It’s not the high flows themselves; it’s what you do in between that’s important to the resources,” she said. Scientists need to watch what happens along the beaches, in the habitats and to the native species, such as the endangered humpback chub. Using an adaptive management, or “learning by doing” approach, researchers can react to the effects of each flood. Scientists have learned that the 2008 flood helped the survival of non-native rainbow trout, a predator of young humpback chub. The amount of sand brought in by tributaries is also critical, researchers found. The high flows not only leave sand along some stretches of the riverbank, they can wash it away along others. If there is too little sand and sediment to begin with, the benefits could be eroded away.

The experimental floods have caused problems for power companies that buy and distribute electricity generated by Glen Canyon Dam. A limited amount of water can be released each year from the dam, based on agreements among the seven states that rely on the Colorado River. When higher volumes are released all at once, less water is available for power production at other times of the year, resulting in lost revenue. The Western Area Power Administration, which markets and delivers electricity from Glen Canyon, estimated that changes in operations at the dam since the experiments began have cost power companies and customers about $50 million a year.

Click through for the cool photo of Grand Falls in the canyon of the Little Colorado River.

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