Easy answer to the question asked in the title of this post, right? The last decade is the driest 10-year stretch since record keeping began on the Colorado River. Of course Lake Mead has dropped because of “drought”, right?

No.

Lake Mead from Hoover Dam, April 2010

During that entire time, thanks to upstream storage and the fact that Upper Basin consumption is still relatively low, Lake Mead continued to get its entire allotment of water every year as required under the Colorado River Compact. Each and every year, 8.23 million acre feet was released from Lake Powell downstream through the Grand Canyon to Lake Mead. That’s the Upper Basin’s Compact-mandated delivery of 7.5 million acre feet, plus the Upper Basin’s share of the U.S. obligation to Mexico under the Treaty of 1944 (pdf). In fact in one of those years, 2008, Mead got extra.

Lake Powell, the upstream of the two great Colorado River reservoirs, responds to climate. Lake Mead responds to human management. Continue reading ‘River Beat: Why Is Lake Mead Dropping?’ »

outflow channel from the Yuma Desalting Plant, which will begin its test phase next week

Joyce Lobeck reports on yesterday’s festivities in Yuma to mark next week’s start of the Yuma Desalting Plant test run:

On Monday, the desalting plant will be started up for a yearlong demonstration run that will produce about 29,000 acre-feet of desalinated water. That means 29,000 acre-feet of water – enough to serve 116,000 people for one year – can remain upriver in Lake Mead.

Not only that, the operation at one-third capacity will provide valuable information about the plant’s condition and performance. This information will be critical in future decisions on whether or how to operate the plant on a long-term basis to stretch water resources in the desert Southwest, said Mike Connor, commissioner of the U.S. Bureau of Reclamation.

29,000 acre feet on a 16.5 million acre foot system is a rounding error, but the symbolism here is not. In the realm of political signaling, it’s worthy of note that two of the biggest shots in western water were there – the Southern Nevada Water Authority’s Pat Mulroy and Mike Connor, head of the U.S. Bureau of Reclamation. Add in the 70,000 acre feet in estimated annual water savings associated with the Drop 2 storage reservoir nearly completed on the All-American Canal (a bonus add-on to yesterday’s ceremony) and you’re starting to talk about real water here. But more importantly, these two projects, and the symbolism surrounding them, provide some picture of the engineering and institutional approaches Colorado River water managers see going forward for this horribly over-allocated river.

I don’t whether it was an omission in the story, or in the event, however, but it’s potentially noteworthy that there was no mention of the folks working on the Cienega de Santa Clara, which represents the environmental tail end of the problems happening upstream.

The Bureau of Reclamation’s Yuma Desalting Plant is scheduled to begin its operational test phase next week. In preparation, a U.S.-Mexican team is ramping up its monitoring efforts at the Cienega de Santa Clara, an accidental wetland in what was once the Colorado River delta. The Cienega is the inadvertent product of U.S. ag drainage that was too salty to put directly into the Colorado River. It’s diverted instead into a channel that bypasses most of the delta, ending at once was empty salt flats. It’s now a small but thriving ecosystem, as Mari Jensen explains in a nice piece on what’s happening in the Cienega now and what happens next:

Courtesy Francisco Zamora

The cienega currently receives about 107,000 acre-feet of agricultural runoff water per year. When the YDP is running, the cienega is projected to receive about 67,000 acre-feet of runoff plus about 10,000 acre-feet of effluent from the plant….

“I think we’ve got a good idea of what the natural range of variability is,” [University of Arizona researcher Karl Flessa] said. “So the question now is: When one-third of the water gets taken out to go through the Yuma Desalting Plant and a salty brine starts flowing toward the cienega instead, how will that affect the health of the cienega?”

To answer that question, the researchers placed instruments that record water quality and water level every 30 minutes at 20 locations all over the cienega. Some instruments are in open water, some are along the edges of the marsh, and others are deep in cattail thickets.

The Cienega raises interesting issues about how to maintain ecosystem flows across an international when no one quite owns the environmental problem. If this were in the United States, the actions of a U.S. government agency would be subject to the Endangered Species Act and other environmental laws.

But it’s in Mexico.

Past reporting on the Cienega and the YDP here, here and here.

There’s a U.S. Bureau of Reclamation graph making the rounds that captures the core issue going forward on the Colorado River Basin.

I first noticed it in Jennifer Pitt’s congressional testimony in early April. At the “Implications of Lower Lake Levels” symposium I just attended in Las Vegas, it showed up in three different talks (Terry Fulp, Brad Udall and Paul Miller – all links to PDFs of their slides).

It also features prominently in the proposal submitted last year by the Colorado River Basin states (another big PDF) that evolved into the Colorado River Basin Water Supply and Demand Study now underway. Here’s how that proposal described the problem in a nutshell:

The Basin States include some of the fastest growing urban and industrial areas in the United States. Nevada, Arizona, and Utah are each ranked among the five fastest growing states in the country. The continued growth and sustainability of the communities and economies of metropolitan areas such as Albuquerque, Denver, Las Vegas, Los Angeles, Phoenix, Salt Lake City and San Diego is tied to future water availability from the Colorado River. Based on a compilation of population projections from various water districts throughout the Basin States, the population dependent on the Colorado River and its tributaries could grow by 25 million over the next 40 years, leading to an increase in water demand of as much as 5 maf annually. Demand for water for other uses including the environment, recreation, and Native American water rights settlements also continues to increase. Potential future increases in temperatures in the Basin, as have been observed in most of the Basin over the past 30 to 40 years, would increase evaporation-transpiration from vegetation, leading to further increases in water use and water lost from evaporation from reservoirs.

There are a lot of embedded assumptions lurking behind The Graph that I haven’t yet worked through. But I like to think of its simplicity in Darwinian terms. Its rapid reproduction and dispersal in the wild suggests it is telling a story that serves a lot of our needs.

The Cienega de Santa Clara, the one remaining major wetland in the Colorado River Delta, is not being drained as a result of Mexico’s 7.2 magnitude earthquake, according to Karl Flessa, the University of Arizona researcher who is part of a team monitoring the ecosystem.

The area was hit hard by the earthquake. The San Diego Union-Tribune’s Sandra Dibble reported Monday on displaced communities adjacent to the wetland. Area soils apparently suffered liquefaction, and irrigation works on which the local farmers depend were damaged.

There were reports, based on NASA’s MODIS satellite data, that a substantial area of the Cienega had lost its water. (The Cienega is a wetland created inadvertently with water from “MODE”, the Main Outlet Drain Extension, which dumps saline ag runoff into what was once barren delta flats.) But in an email sent to the Cienega monitoring community (quoted here with permission), Flessa reports that field team measurements show no change in water levels:

I’ve just returned from the Cienega de Santa Clara and can report that it has not, and is not, draining. The recent earthquake has not caused the Cienega to drain….

The field crew is downloading data on water levels (among other things) at all our sites. While we may yet see some evidence of earthquake effects in these data, major changes in water level in the Cienega do not seem to have occurred.

The MODE/Bypass Drain appears in good shape and continues to deliver water to the Cienega.

There has, indeed, been some flooding in the area. Some has likely resulted from liquefaction (groundwater coming to the surface) and some from breaks in levees and irrigation canals….

Other, non-earthquake-related sources of water in the vicinity include recent rains and high tides. Sorting out the effects of the earthquake from “normal” variability will take some time.