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More than a decade has passed since the waters

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of the Colorado have reached the Sea of Cortez.

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During that time, the lower reaches of the river have seen a decline in the amount of healthy vegetation.

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But a historic agreement between the U.S. and Mexico

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provided a pulse of water to flow down the riverbed and into the delta region.

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The lower Colorado River straddles the border between Mexico and the U.S.,

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and the two countries are collaborating to study the hydrologic and ecosystem effects of the pulse flow.

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For several weeks in the spring of 2014,

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a pulse of water passed through the Morelos Dam

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totalling 130 million cubic meters,

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enough to fill 52,000 Olympic swimming pools.

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The water quickly filled the formerly dry riverbed.

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Much of the water soaked into the ground in the first half of the journey,

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replenishing the supply of ground water. From there it is able to nourish and revitalize

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the trees, shrubs, and grasses in the riparian corridor surrounding the river.

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Scientists with the U.S. Geological Survey

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are using data from satellite observations to track how the vegetation responds

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Data from Landsat 8 shows a 40% increase in green vegetation where the surface water flowed

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and an overall 23% increase throughout the riparian corridor.

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The difference between 2014 and 2013 is most noticeable in the wetlands of the lower delta region.

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Going forward, scientists from both countries will continue to study the impact of the pulse flow;

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looking to see whether new trees and shrubs take root,

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and how new vegetation affects resident and migratory birds.

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[music]

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