Arizona Water Resource Newsletter
Water Resources Research Center
College of Agriculture and Life Sciences
The University of Arizona, Tucson AZ


About vol. 13 no. 4 AWR main home pull down menu   News Briefs

Yuma Desalting Plant on Test Run


A special event celebrated the startup of the Yuma Desalting Plant for a 90-day trial period, from March 1 to May 31, operating at 10 percent capacity. This was a significant achievement for a facility once viewed as a white elephant, a relic of a bygone era, but now viewed as a project worth revisiting during drought-struck times. This is the first time in 14 years that the $250-million, reverse-osmosis facility has been operating.
The desalter startup was the latest chapter in a complicated water resource tale that began when highly saline water of insufficient quality to deliver to Mexico per treaty obligation was carried via a bypass canal to the Gulf of California. Construction of the plant was completed in 1992; its was not needed, however, because those were flush times on the Colorado River. The abundant flow enabled U.S. to meet Mexican obligations without operating the plant.

The test will determine whether the plant can in fact be restarted. Some question whether it can since it has been mothballed for so long. Also, the demonstration run will test various technological refinements that have been incorporated into the plant since 1993. It will also validate cost estimates for operating the plant.
Operating the plant full-time would have a significant water resource payoff of about 78,000 acre feet per year, left in Lake Mead for use by Lower Colorado River states.
The U.S. Bureau of Reclamation has not yet decided about the future of the plant which is one among several options being considered to extend water supplies in the Colorado River Basin.

Arizona Takes Stand Against Invading Quagga Mussels

It has been a quiet invasion, the quagga mussel slipping into Arizona waterways with hardly a splash heard, probably conveyed undercover on a boat that had floated in the mollusks-infested waters of the midwestern or northeastern United States. Now that it is here, officials in Arizona are organizing a high-stakes battle to halt the invasion that threatens water delivery and canal operations in the states.

The quagga mussel is related to the notorious zebra mussel that has been a scourge in the Midwest and Northeast, breeding in the Great Lakes, along the Mississippi River and in other lakes and waterways and costing millions of dollars in efforts - all unsuccessful - to control and eradicate them.

Their arrival in Arizona has been a threat long anticipated, with wildlife officials taking actions and issuing warnings in the hope of preventing the mollusks from infesting state waters.

First noticed in Make Mead earlier in the year the quagga have since migrated down the Colorado River into Lake Mohave and Lake Havasu. That quagga are in Lake Havasu is particularly ominous to Arizona since the lake is the direct source of Central Arizona Project's Colorado River water. Water from the lake is pumped into the aqueduct to flow 336 miles to Phoenix and Tucson. The quagga mussel has been found at the Lake Havasu CAP intakes and the first section of the aqueduct. This is worrisome to the Salt River Project; its system connects with the CAP at Granite Reef Dam.

With much of the state's water supplies conveyed through canals, officials are very concerned that the rapidly breeding mussels can be a major and expensive nuisance if they build up along concrete-lined canal surfaces and encrust submerged pipes and equipment.

The Salt River Project has adopted a biological control strategy and introduced 38,000 redear sunfish to its canals. The redear sunfish can crush the shell to feed on the mollusk. It is not expected to eradicate the quagga but to control the nuisance to some extent. Native to the southeastern region of the country, the redear sunfish will share the SPR canal with two other fish that had previously been introduced to manage the canals: the western mosquito fish whose task is to control mosquitoes and the white amur introduced to control weeds.

The CAP has adopted the same strategy of introducing redear sunfish to control the mussel in its system, with about 30,000 fish released in its canal in Parker.

Some scientists offer a hopeful note by theorizing that the warmer waters of Arizona may not be conducive to the breeding of quagga who have mainly thrived in the cooler waters of other regions. The approaching summer months will test this proposition.

Less Toxics Released to Arizona Water

Arizona industries scored a seven percent decrease in toxic releases to water from 2004 to 2005 according to new data released by the U.S. Environmental Protection Agency. Water releases declined from nearly 7,000 pounds in 2004 to approximately 6,000 pounds in 2005. The same data shows that Arizona industries reported a 3 percent decrease in toxic chemicals released into the air.

The data comes from the EPA's Toxics Release Inventory, an annual measure of toxic chemical releases, transfers and waste generated by facilities in the United States. Total releases include toxic chemicals discharged to air, water, underground injection, land (including landfills), and the amount transferred off-site for disposal. Data provided does not mean that facilities with elevated levels are out of compliance with state, local or federal environmental regulations.

The reporting of data to the Toxics Release Inventory is required under the federal Emergency Planning and Community Right-to-Know Act, passed in 1986.

This program has been credited with arming communities with valuable knowledge and encouraging facilities to reduce their releases of toxic chemicals into the environment through source reduction or pollution prevention measures.

Fact sheets and additional information on the 2005 TRI data for Arizona are available online at http://www.epa.gov/region09/toxic/tri/report/05/arizona.pdf The following web sites also provide
useful information on TRI: http://www.epa.gov/triexplorer and http://www.epa.gov/enviro

ASU's Pervious Concrete Parking Lot is Water Smart

A new celebrated installation at the Arizona State University Art Museum is not in a gallery but is its parking lot which has recently been redesigned to showcase a state-of-the-art environmental-friendly alternative to conventional pavements. The featured attraction is pervious concrete.

ASU Parking Lot

Pervious pavement has various environmental advantages over the conventional asphalt parking lot. A mixture of Portland cement, coarse aggregate (stone), water and admixtures, pervious concrete is highly porous, containing 15 - 25 percent void space that interconnect within the pavement to form channels. These enable water and air to pass through the paved area.

This high porosity accounts for its environmental advantages over conventional lots. One advantage is that pervious concrete naturally filters storm water, reducing or eliminating pollution through natural biological processes. Larger pollutants in water infiltrating the soil beneath the pavement are filtered out. Microorganisms further control pollution by breaking down pollutants until they are inert. The result is a reduced pollutant load entering streams, ponds and rivers.

Groundwater recharge also benefits; instead of flowing off a surface to a storm water drainage system, water infiltrates the pervious concrete, eventually reaching the aquifer. Trees and other plant life surrounding a pervious concrete parking look better and live longer, their root systems benefitting from the improved access of air and water. This is an natural amenity achievable even in densely developed urban areas.

The storm water management applications of pervious concrete are especially useful. Faced with stricter storm water runoff regulations, property owners will likely be burdened with increased cost for installing an adequate drainage system when developing real estate. By reducing runoff from paved areas, pervious concrete lessens the need for separate storm water retention ponds and enable the use of smaller capacity storm sewers. Property owners are thus able to develop a larger area of their property at less cost.

The U.S. Environmental Protection Agency recognizes the proper utilization of pervious concrete as a Best Management Practice for first-flush pollution control and storm water management. Pervious concrete also earned kudos from the U.S. Green Building Council's Leadership in Energy and Environmental Design program for integrating paving and drainage. This reduces the amount of land needed to manage storm water.

Another bonus of using pervious pavement is reduced maintenance. It is expected to last about six times longer than conventional pavement.

The ASU project includes alternative water and landscaping design to mitigate the effects of the Urban Heat Island. By absorbing and storing less heat, pervious surfaces reduce urban heat buildup and heat radiation caused by conventional asphalt and concrete pavements. Urban heat buildup has been shown to indirectly affect water use. Planners also considered aesthetics to ensure an enhanced visual appeal.

The parking lot also serves as a demonstration project enabling researches to study its performance. Kamil E. Kaloush, co-director of EPA-designated National Center of Excellence on SMART Innovations for Urban Climate and Energy at ASU says "We wanted to sample the material, know more about its strength characteristics and durability."

Research will be ongoing at the ASU lot, with temperature and moisture sensors measuring its environmental performance for comparison with other non-pervious ASU parking lots. ASU researchers will use the data to develop technical guidelines for installing pervious parking lots.

One result is already obvious. Kaloush says that the parking lot area had problems with drainage. "When it rained it quickly flooded, and parking services would pump the water. It is quite an improvement this year because a lot of that water can go through the pavement."

The cost of pervious surfaces, which is about twice as much as traditional forms of pavements, will likely discourage its widespread use. ASU researchers expect, however, that its cost will lessen as developers and communities take an interest in the product.

Although available for 20 or 25 years, pervious concrete has not been extensively used in Arizona. Kaloush says research results will be shared with local communities since many cities have expressed an interest in the surface.

He says one project getting serious consideration is surfacing a lot outside the Tucson zoo; he invites researchers in the Tucson area who might want to participate in the project to contact him. (Kamil.Kaloush@asu.edu)

The project is a cooperative effort involving ASU's National Center for Excellence. The center is an extension of the university's Global Institute of Sustainability and the Department of Civil and Environmental Engineering in the Ira A. Fulton School of Engineering. Other program partners include ASU Parking and Transit Services, the Arizona Cement Association, the CEMEX USA company, Progressive Concrete Works Inc, and Border Products.