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A white, oval shape logo, with the title WaterShare centered in green letters.  There is a blue drop of water and the title.

NatureWater Lesson Plans
Problems & Solutions:

MANAGING FLOWS WITH FISH IN MIND
Problem:

Fish need water, and so do people. When people remove water from streams and rivers, they can hurt fish habitat if they take too much. For the fish, less water in the river means less habitat available, as parts of the channel dry up or become exposed to predators. The temperature of the water is influenced by the amount of in-stream flow. Smaller amounts of water heat up faster than larger amounts. As flows decrease, water temperatures increase. Salmon and steelhead like cold water. Many fish deaths in low flow conditions are due to high water temperatures.

Dams profoundly change rivers. They hold back the high flows, which happen naturally in the winter and spring. High flows and floods are part of a river's natural cycle. They flush out fine sediment and bring a regular supply of spawning gravel from upper portions of the river system. Flushing flows shape the river channel and create diverse habitats - deep pools, glides and riffles. Regulated, low flows often result in rivers clogged with fine sediment and depleted of spawning gravel.

Solutions:

Water management care means water to share. Many farmers already are employing the best water conservation methods, and many people conserve water in their homes. As our population grows the need for water efficiency will also increase. It is vitally important to the salmon that every water user becomes a steward of this resource, learning about and applying water conservation practices. Keeping more water in the river is the best solution to flow problems.

Pulse flows are used to flush the Trinity River, where about 90% of the natural flows have been diverted into the Sacramento River to provide water for Central Valley farmers. By sending pulses of high flows down the river, people hope to push out some of the silt and sand that has clogging the spawning beds. Pulse flows also clear out sediment which has filled up the deep pools fish need.

Controlled river flows can also be used to help fish migrate. In the Shasta River, farmers volunteer to suspend diversions for a period of time in order to send a strong pulse of water downstream for several days in the spring. They hope the stronger current encourages the salmon fry to begin their downstream migration before summer arrives. Summertime water temperatures often rise to lethal levels.

Pictures of Flow Management
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