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Keeping Water In Streams

Dewatered Streams Map
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Year-round flowing streams are an important economic benefit to the public and adjacent communities. We are all responsible for helping resolve the instream flow dewatering problem. It is consistent with MRA’s long term goal of keeping fish in streams. Both state and federal Superfund programs, as well as Montana’s Natural Resource Damage Program require normal streamflows. Federal agencies will not fund long-term restoration projects if the stream is subject to chronic or periodic dewatering. If an irrigator does not water for a day, there will be some diminution of his crop, but if a stream runs dry for a day, it will take up to 8 years for the micro-life to return so that fish may reoccupy the stream!

2,835 miles of streams (209 reaches) are Chronically Dewatered each year
1,387 miles of streams (83 reaches) are Periodically Dewatered each year

4,222 miles of Montana streams on 381 different rivers and creeks are chronically or periodically dewatered each year.

97.6% of diverted water from streams is used for irrigation.

Less than 5% of Montanans hold irrigation water rights.

Agriculture pays $2.50 for 1 acre/foot of water.

The City of Bozeman pays $35 per acre/foot of water.

Los Angeles pays $250,000 per acre/foot of water.

Twenty percent of irrigation water is taken up by plants - 80% evaporates or runs off. Irrigation runoff is detrimental to most aquatic life due to warming, fertilizers, pesticides and herbicides dissolved in the water as it moves across the fields. The heavily laden water flows back into the streams or underground aquifers.

Click the map above to see dewatered streams that are significantly reduced in streamflow below the point where aquatic life and fish are seriously impacted. The map only includes streams that are important fisheries or valuable in juvenile fish rearing.

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