On Sunday, March 23, a surge of water, referred to as “pulse flow”, was released from the Morales Dam into the dry and parched riverbed below in a binational effort to restore the once vibrant Colorado River Delta. As the water headed south across the US/Mexican border, it marked first time water flowed to the Delta in 50 years.
Dry for Decades
For millions of years the Colorado River flowed from the Rocky Mountains, down through the floodplains of the Delta, and into the Gulf of California/Sea of Cortez. However, due to dams and diversions, the Colorado River has not regularly flowed to the Delta since 1960. As a result, the once lush ecosystem, teeming with plants, fisheries, numerous bird species, marine life, and wildlife became dry – and desolate. Of the two million acres of what was once wetlands, only 10% of the vegetation remains.
Hope springs eternal
A series of brief floods in the 1980s and 1990s showed that a little water can go a long way in restoring the Delta’s ecosystems. That sparked the efforts to restore a Delta many feared had already died. With hope in hand, a revival team formed.
Fast Forward to this week: the pulse flow started with an initial release of water that will increase for several days and then slowly be reduced, mimicking how the river would naturally flow during spring flooding. The initial pulse flow will help restore water to the area, as well as spread plant and tree seeds down the river corridor where they will embed in the now wet soil and take hold – beginning the regrowth. This engineered release of water, will be complemented by restoration work on the ground, including the planting cottonwood trees.
The initial surge flows will amount to 105,000 acre feet of water (less than 1% the average annual flow), which is much less than the historic floods. Since the Delta has been starved of water for over 50 years, the timing, duration, and overall impact of the flows will be carefully monitored. The desired goal is for cottonwood and willow trees to take root, increase groundwater, and help return birds, plants, wildlife, as well as marine life. A little can go a long way.
The effort is particularly important in restoring the once robust bird populations, including migratory birds like the warblers and flycatchers, as well as local birds, many of which are now endangered. In the longer term, the efforts will hopefully result in the return of rural communities and economies on both sides of the border to the area. This week is the first time the two countries have put water back into the dry riverbed for environmental purposes. It’s also an exciting step forward to reclaiming the Delta.
Watch the video below to learn more:
Breakthrough agreement
While the environmental benefits to the Colorado River and its Delta cannot be underscored, the agreement helped bring the pulse flow about is equally important. The release of water into the Delta is part of an historic agreement between the United States and Mexico. It provides for flexible water sharing and storage, adapting for times of surplus or drought, as well as better management of the Colorado River.
These two great nations were able to bring creative, science-based solutions together with good old fashioned diplomacy in an effort to restore the once lush and diverse river Delta. It’s the type of water sharing agreement and big-picture thinking we need to ensure the long-term health and sustainability of the Colorado River.
Your Water Advocate,
Theresa