In The Colorado Delta, A
Little Water Goes A Long Way

This week is World Water Week and a coalition spanning the US-Mexico border is a perfect example of this year’s theme-water cooperation. The group is thinking outside the box to restore the Colorado River delta – using water rights markets, recaptured wastewater, and a groundbreaking new federal deal – that’s breathing new life into an ecosystem widely assumed to be gone forever.

6 September 2013 |  The Colorado River hasn’t reached the sea in fifteen years.

The two-million acre delta where a young Aldo Leopold once paddled his canoe through “a hundred green lagoons” abounding with life (“At each bend we saw egrets standing in the pools ahead…Fleets of cormorants drove their black prows in quest of skittering mullets; avocets, willets, and yellow-legs dozed one-legged on the bars; mallards, widgeons, and teal sprang skyward in alarm…”) today is a vast, empty mud flat.

For years, scientists assumed it was a dead ecosystem.

After all, the free-flowing river itself disappeared at the Morelos Dam a hundred miles upstream, where the meager portion of water left to Mexico after seven US states took their share was then funneled into irrigation canals or off to the residents of the city of Mexicali. No water passed through the dam, much less was left over for the environment: the Colorado is already over-allocated by sixteen percent. Nine-tenths of the original wetlands are gone. Much of the delta has become desert.

But in the 1980s and 1990s, something unexpected happened. During El Nií±o years, sometimes the Colorado ran high, and then water would be released through the dam to prevent flooding upstream.
In the aftermath of these floods, the landscape looked palpably healthier. As a team of scientists wrote in the Southwest Hydrology Journal, “riverbanks once choked with saltcedar and other salt-tolerant shrubs have sprouted new cottonwood and willow trees following each flood event. The floods wash salts from the riverbanks and wet the soil, allowing tree seeds to germinate and grow. The trees grow in stands…that correspond to the high water mark of each flood.”

The delta was more resilient than it seemed.

To the east of Morelos Dam, a concrete canal crosses the border. It runs for 75 miles, from the Wellton-Mohawk Irrigation District in Arizona into Mexico’s Sonoran Desert, draining agricultural wastewater from farmlands.

At the mouth of the canal, another startling thing happened. As water began flowing in the late 1970s, a vast wetland appeared. La Ciénega de Santa Clara today has grown from 500 acres to perhaps forty times that size, hosting thousands of songbirds, waterbirds, and fish.

To the astute observer, the message was clear: in the delta, a little water goes a long way.

A Water Trust

In 2008, a coalition of non-profit groups hailing from both sides of the border, including the Sonoran Institute, Pronatura Noroeste, and the Environmental Defense Fund, decided to act on that knowledge, and tap a new source for restoring water to the river: the market.

They created the Colorado River Delta Water Trust (CRDWT), which buys water rights on the open market and effectively retires them, restoring the water to the river (a mechanism known as “instream buybacks” or “water buybacks”).

“We purchase irrigation water rights in the Mexicali Valley from willing sellers, usually farmers,” explains Osvel Hinojosa, Pronatura Noroeste’s Water and Wetlands program director. Under Mexican law, the water right can be separated from the land and the water redirected to uses in other places. Now, instead of irrigating agricultural fields, the water is once again irrigating plantings of native trees and inundating riparian areas to encourage native vegetation growth.

Their biggest goal, though, has been to secure enough water to maintain a small base flow, which means the portion of stream flow in a river contributed by groundwater or other subsurface sources. Baseflows are the sustained background levels present even during dry periods.

No one has ever bought water on behalf of the environment before in Mexico, though similar mechanisms have worked in the United States and Australia. Nor has a water ‘buyback’ mechanism like this ever been carried out across national boundaries, with conservation groups pooling resources to save the river that links their countries. The CRDWT is doing something almost entirely unprecedented, both in conservation finance and in successfully cooperating to restore a transboundary basin.

Working through water markets lets the coalition act quickly, explains Hinojosa. “We saw great potential to reach an allocation of up to 60 million cubic meters per year, and particularly water with very good quality.” Pronatura Noroeste already used treated wastewater and agricultural drainage to feed marshes and estuaries in the delta, but to bring back forests in the riparian zone (i.e. the area along the banks of the river), they needed cleaner water, and the best place to get it was to simply buy it on the market.

The Sonoran Institute estimates that in the long term, the lower Colorado needs 50,000 acre-feet (61.7 million m3) (one acre-foot, or AF, represents the volume of water needed to flood an acre of land to one foot deep, or about twice as much water as a household in the US West uses in a year) for baseflows annually. Buying these rights on the Mexican market will probably cost between US $12-15 million.

Through the market, the water trust has secured about 3200 AF to date and invested about US $1 million. Their goal is to triple that in the next five years.

The buybacks are just one arrow in a quiver. The coalition stays busy: it’s also worked to secure another 6080 AF (7.5 million m3) per year of treated wastewater from the Las Arenitas Waste Water Plant to restore flows in the Hardy River, a tributary of the Colorado. CRDWT has participated in binational negotiations between the US and Mexico to ensure that the agricultural wastewater flows that maintain the Ciénega de Santa Clara wetlands will continue. They’ve protected 25,000 acres (10,000 ha) of mudflats and estuarine habitat in the delta, plus another few thousand along the Hardy and the Colorado rivers, in the El Doctor wetlands, and in riparian corridors. The idea is to create a network of restored sites: if that can be done, much of the habitat functionality for wildlife will return.

Piece by piece, they’re reassembling the delta.

“This as an ecosystem with high resiliency, and we have learned that with a little bit of water we can achieve significant restoration,” says Hinojosa.

Minute 319

It seems the higher-ups are listening. Last November, the CRDWT became a key partner in an agreement between the US and Mexican governments that aims to reconcile management of the Colorado River to certain environmental realities.

Minute 319, as the agreement is known, does a few important things. First, it spreads the effects of drought and flush years more evenly between the two countries. Previously, Mexico’s entitlement was more or less locked in: every year the US was required to send about 1.5 million AF (1.85 billion m3) of water to Mexico annually, except in cases of “extraordinary drought,” which were never defined in the original 1944 treaty between the two countries. Now, there’s a process for revising that allotment downward to reflect drought, and in turn Mexico, which lacks its own storage capacity, can keep its ‘extra’ water in wetter years behind the Hoover Dam for later use.

And for the first time, the two countries have agreed to set aside some water for the environment. Minute 319 dedicates a total of 158,000 AF (1.95 billion m3) over a five-year period: a third will support base flows, the rest a one-time ‘pulse’ flow, to mimic both historical background levels and the large springtime floods that existed in the Colorado in the years before the dams were built.

The Colorado River Delta Water Trust is responsible for securing a third of that water through its water right buybacks.

To deliver the rest, the US has agreed to contribute US $21 million to help pay for infrastructure improvements and environmental projects in Mexico, where irrigation infrastructure was badly damaged in a 2010 earthquake. These conservation projects and irrigation efficiency improvements are expected to create enough water savings for the pulse flow, so existing water entitlements won’t be cut.

An initial pulse flow of 105,000 AF (129.5 million m3) is scheduled tentatively for 2014, and no later than 2016.

Minute 319 was widely lauded as a historic deal and a landmark for transboundary cooperation. Former US Secretary of Interior Ken Salazar called Minute 319 “essentially the most important agreement that has ever been put together between the United States and Mexico on water in the Colorado River.”

“The environmental component was an essential part of the negotiations,” says Hinojosa. “It opened the door and set the table for binational collaboration in more difficult topics, such as shortage criteria, joint investments in infrastructure, and storage of Mexican water in the US.”

“Local communities are the cornerstone of this process”

Within the Mexicali Valley, support runs just as high. “We have been working with these communities for seventeen years, to get them involved and excited about the restoration of the Colorado River delta,” Hinojosa points out.

Restoration projects are creating jobs, for one thing. The Mexican Federal Government provides funding for a temporary employment program in the Valley, which pays about a hundred people each year to clear invasive salt cedar and plant cottonwood, willows, and mesquite in its place.

Locals welcome these jobs, and the water trust’s investments in restoring a natural landscape that many older residents still remember.

“A farmer sold us recently 20 water rights (200,000 m3 or 162 AF per year),” says Hinojosa. “His story is similar to many of the transactions we have done. He moved to the Mexicali Valley in the 1950s, and obtained from the government the land and water rights as part of an ejido [a form of communally held land common in Mexico]. He formed a family and was able to send his children to college in Mexicali, and eventually the family moved to the city. He finally retired and the family is not interested in continuing the farming activity, and placed the water rights in the market.”

“Usually, these water rights are purchased by other farmers in the region, but also by the cities of Tijuana and Mexicali, and then the water goes outside the Valley. Since with our activities, we are keeping the water in the district and for programs that create local benefits, we receive the support from the sellers and the farming community.”

The river stirs to life

These days, the Colorado River basin is locked in the worst drought in a century. But sometime soon – whether in a year or three – the river will be connected with the sea once again during the planned pulse flow.

Long-absent local birds and marine species are expected to come back, along with the 300,000 migrating waterbirds that have historically stopped in the delta for the winter. A wealth of habitats stretching over 60,000 hectares – the forests, marshes, lagoons, mudflats and estuaries that Leopold once explored – will appear once more on the landscape.

Minute 319 is a five-year agreement, and the coalition is already thinking about the next round of negotiations. Hinojosa says at the top of CRDWT’s priorities is demonstrating that their efforts are working, and to learn as much as possible about the ecological recovery process in the delta so they can craft an even better deal next time.

The CRDWT is also exploring new funding sources to ramp up their buyback activities: they’ve moved beyond traditional foundation support to a partnership that channels money from a US buybacks program, Bonneville Environmental Foundation’s Water Restoration Certificates, to purchasing water rights in the delta. They’re also working with the Redford Center, on a public fundraising campaign called Raise The River launching this week.

“There are huge opportunities,” says Hinojosa. Not only for the Colorado River: “This process can set a precedent of international cooperation for the dedication of environmental flows and restoration.”