River Report Issue: Spring 1999 by S. Joshua Newcom

Deciding about the Colorado River Delta

Rejuvinated wetlands raise new issues about where flood flows should go

It starts as a trickle in the mountains of Colorado -- snow and ice melting to the demand of rising temperatures. Tumbling thousands of feet, the alpine water melds into a succession of creeks, springs and rivers, forming the waterway known as the Colorado River.

Before the creation of state and international boundaries, the unchecked Colorado wound its way through the southwestern corner of North America and into what is now know as Mexico. There, a combination of nutrient-rich water and silt from the river created widespread wetlands -- at times extending from southern California where the Salton Sea is today to the northern tip of the Gulf of California (gulf). Bordered by mountains and desert, the historic delta comprised over 2.5 million acres of wetlands and provided habitat for an estimated 400 species of plants and wildlife. Along its shores, some 20,000 Cocopah Indians made a life from the ecosystem by fishing, hunting and farming. The area became known as the Delta del Río Colorado -- the Colorado River Delta.

With completion of Hoover Dam in 1935, the United States began damming the Colorado River -- on a much larger scale than in the past -- to meet the needs of burgeoning cities and farms in the West. Nearly 30 years later, the last of the great dams on the Colorado River was completed when the gates of Glen Canyon Dam closed in 1963. Mexico, which at one time received the full flow of the Colorado, agreed to an annual delivery of 1.5 million acre-feet (plus up to 200,000 acre-feet in surplus years) of water under the Mexican Water Treaty of 1944. All of Mexico’s river apportionment is typically consumed by agriculture and municipal and industrial (M&I) uses in the Mexicali and San Luis valleys. Thus, in a normal water year, the last drop of the Colorado River evaporates in Mexican sands – about 1,450 miles from its birth and short of its natural termination in the gulf.

Increased public interest in environmental issues over the years has substantially boosted attention to the delta from governments, non-governmental organizations (NGOs) and environmental groups on both sides of the border. According to U.S. Fish & Wildlife Service (USFWS) figures, over half of the wetlands in the United States have disappeared since 1780. And according to the California Resources Agency, California, a major stopover for birds along the Pacific Flyway, has only 10 percent of the wetlands that existed before European settlement. The shortfall in this rich habitat has led some to see Mexico’s delta as a potential saving grace.

Nearly two decades of heavy rain and snowfall, as well as the filling of Lake Powell, have boosted river flows into Mexico including in 1998 when water from the Colorado River stretched all the way to the gulf. Flows from the Colorado River have reached the gulf five times since 1983. Wetlands in the region have benefited from the flood flows that have regenerated vegetation and fish and wildlife populations. Sections of the delta and the northern gulf support several endangered species like the totoaba, a fish species once used commercially and for sport fishing; the vaquita, the world’s smallest porpoise and rarest ocean mammal; the desert pupfish; and endangered species of bird such as the southwestern willow flycatcher and the Yuma clapper rail.

Questions now abound about if and how to maintain and enhance these vital wetland ecosystems, but a solution – like anything on the Colorado River – is far from easy. In an act of protest, two environmental groups within the United States have bowed out of a steering committee for the Lower Colorado Multi-Species Conservation Program (MSCP) claiming the program falls short of addressing environmental needs in the Mexican delta. (The MSCP is an environmental management plan for the Lower Colorado River being implemented by the Bureau of Reclamation (Bureau) in cooperation with the USFWS, the Lower Basin states, Tribes and the National Park Service. (See Winter ’98 River Report.) Nine environmental groups signed a letter, dated March 12, 1999 and addressed to Secretary of the Interior Bruce Babbitt, claiming the management plan falls far short of looking at the Lower Colorado ecosystem as a whole by stopping at the border.

“Eighty percent of the top Lower Colorado River habitat is in Mexico,” said Tom Latousek, a conservation associate with American Rivers (one of the letter’s signatories), an organization that listed the Colorado River Delta as one of its top 10 endangered rivers in North America in 1998. “It is a biological reservoir of sorts and if you enhance that habitat, you enhance the recovery of species all the way up the Colorado River into the U.S.”

But state interests and the United States government remain cautious about supplying more water to Mexico. “We don’t have any jurisdiction over how Colorado River water is used once is crosses over the border into Mexico,” said Robert Johnson, regional director for the Bureau’s Lower Colorado Region.

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