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T h e R e s o u r c e f o r S e m i - A r i d H y d r o l o g y

Water-EnergyNexus

Volume 6/Number 5 September/October 2007

www.ismar2007.org

Keynote Speaker: Dr. Ed Bouwer, Johns Hopkins University

Over 100 technical presentations:• Speakers from 27 nations, 14 US states• Wide range of topics related to aquifer recharge• Field trips to Phoenix area recharge sites• Hardbound Proceedings volume• Post-Conference field trip to Las Vegas, NV• Post-Conference sight-seeing tours

Optional Pre-Conference Workshops:• Surface and Well Recharge Methods• Field Methods for Recharge Sites• Geochemical Techniques in MAR Studies• Design of Recharge and Recovery Wells

Visit www.ismar2007.org for more program details.

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Register for ISMAR6 online at

Sponsored by:3R ValveCentral Arizona ProjectClear Creek AssociatesHDRSalt River ProjectWaterloo Hydrogeologic

The Arizona Hydrological Societyin cooperation with IAH, ASCE, NWRI, and UNESCOpresents the

6th International Symposium on Managed Aquifer Recharge

Oct. 28 - Nov. 2, 2007Pointe South Mountain ResortPhoenix, Arizona

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To really understand the nexus between water and energy, carry a five-gallon bucket of water up two flights of stairs. The stuff is heavy and can’t be moved around without considerable effort. Yet without much hesitation, we pump huge quantities from great depths, pipe it around our states, treat it, deliver it to its point of use, collect it again, re-treat it, and dispense with it. And energy production itself requires water. We just spent another long, hot summer grateful for central air conditioning powered by electricity. But whether it was generated by hydropower, nuclear power, or thermoelectric power, a good amount of water was consumed in its production. Water and energy are intrinsically linked; we can’t have one without the other. This issue takes a close look at how much of one is needed to produce the other.

Thanks to all the contributors to this issue, and also to our advertisers.

Betsy Woodhouse, Publisher

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Southwest HydrologyPublisher

Betsy Woodhouse

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Contributors

Advisory BoardDavid Bolin, R.G.Charles Graf, R.G.John HoffmannJeff Johnson

David Jordan, P.E.Karl Kohlhoff, P.E., B.C.E.E.

Stan LeakeAri Michelsen, Ph.D.

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Martin Steinpress, R.G., C.HG.

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Southwest Hydrology is published six times per year by the NSF Center for Sustainability of semi-Arid Hydrology and

Riparian Areas (SAHRA), College of Engineering, The University of Arizona. Copyright 2007 by the Arizona Board of Regents. All rights reserved. Limited copies may be made for internal use only. Credit must be given to the publisher. Otherwise, no part of this publication may be reproduced without prior

written permission of the publisher.ISSN 1552-8383

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CONTACT USSouthwest Hydrology, The University of Arizona, SAHRA

PO Box 210158-B, Tucson, AZ 85721-0158. Phone 520-626-1805. Email [email protected].

Andy AdenHossein Ashktorab

Anthony BrazelAnne Browning-AikenArunima Chatterjee

Ronnie CohenPatricia Gober

Arturo KellerJeannine Larabee

Dana LarsonCheryl Lee

Melanie LenartJeffrey J. Lukas

Christopher A. Scott

Hyeyoung Sophia SeoTerry W. Sprouse

Stacy TellinghuisenRobert G. VaradyR.C. Wilkinson

Connie Woodhouse

From thePublisher


Navajo Generating Station near Page, Arizona. Photo donated and copyrighted (2004) by Bill Kutcher. Visit www.pbase.com/ibill.

4 • September/October 2007 • Southwest Hydrology

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This publication is supported by SAHRA (Sustainability of semi-Arid Hydrology and Riparian Areas) under the STC Program of the National Science Foundation, Agreement No. EAR-9876800. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of SAHRA or of the National Science Foundation.

Inside This Issue

16 The Water-Energy NexusRonnie CohenEnormous amounts of energy are required to move water from source to tap and beyond. Water conservation not only saves water, it saves the energy required to collect, pump, treat, deliver, heat, cool, and dispose of it. Turning off the tap can be as energy effi cient as turning off the lights!

18 Energy Demands on Water Resources: The Federal PerspectiveBetsy WoodhouseA recent Department of Energy report examines the interdependencies of energy and water in the United States.

20 California’s Energy-Water Nexus: Water Use in Electricity GenerationDana Larson, Cheryl Lee, Stacy Tellinghuisen, and Arturo KellerResearchers looked at total water requirements and water consumption for nine primary energy sources, and evaluated potential future energy scenarios for California in light of water use and the state’s renewable portfolio standards.

22 Water Usage for Current and Future Ethanol ProductionAndy AdenNew federal initiatives to increase use of renewable and alternative fuels have spurred massive growth in the ethanol industry. What are the true water and related energy demands for growing corn and other plants for ethanol production, and how could the process become more effi cient?

24 Water Use Effi ciency: Saving More than WaterJeannine Larabee and Hossein AshktorabThe Santa Clara Valley Water District initiated several innovative water recycling and water conservation programs that have resulted in substantial energy savings and reduced emissions of carbon dioxide and other pollutants.

26 Linking Water and Energy along the Arizona-Sonora BorderChristopher A. Scott, Robert G. Varady, Anne Browning-Aiken, and Terry W. SprouseWater and energy don’t stop fl owing at the international border. Arizona and Mexico are coordinating their efforts along the border to improve both water and energy effi ciencies, particularly in light of forecasted climate change.

28 Water-Energy Trade-Offs Between Swamp Coolers and Air ConditionersArunima Chatterjee and Melanie LenartIn the dog days of summer, have you ever wondered about the overall water and energy tradeoffs of evaporative cooling versus air conditioning? This article examines the total energy and water consumed in each method, the climatic impacts of the way energy is converted, and ways to improve cooling effi ciencies.

Departments8 On the Ground

Using tree ring data in water planning, by Connie Woodhouse and Jeffrey J. LukasUrban climate change and water use, by Anthony Brazel and Patricia Gober

12 GovernmentEPA issues determination on contaminantsMajor Texas water bill passes Voluntary mine cleanup gets easierNew wetland guidance from fedsTiny delta fi sh wield big powerReclamation tests Yuma desalterSalton Sea restoration plan selected

12 Hydrofacts

33 R&DCA ag land continues to sinkMethane mining water useArizona earth fi ssures mappedTexas research recognizedNM water quality evaluatedPortable pathogen test kits$4.6 M grant funds water data site

37 Society PagesRecharge experts to meet in Oct.ASCE’s infrastructure planWater Practice journal debutsAt-risk rivers make top 10 listsQuinn named new ACWA directorReuse facilities database available

39 In PrintReview of Sustainable Water Management: Guidelines for Meeting the Needs of People and Nature in the Arid West

40 EducationRainLog and RainMapper

41 Software ReviewSuper Slug, reviewed by Hyeyoung Sophia Seo

42 Calendar

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Water-Energy NexusMoving and treating water consumes energy, and producing energy nearly always consumes water: the two are tightly linked. The good news is that conserving one results in savings of the other as well. By understanding how much water is required to produce various kinds of energy, we can move toward more water-effi cient energy production. In turn, recognizing how much energy is needed for various components of our water systems will help us identify opportunities for greater effi ciency. This issue’s articles look at both sides.


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Applying Tree-Ring Data to Water Resource Planning

Connie Woodhouse – Department of Geography and Regional Development, University of Arizona and Jeffrey J. Lukas – Institute of Arctic and Alpine Research, University of Colorado

Trees that reflect variations in moisture in their ring-width patterns can be used to reconstruct records of streamflow for past centuries, extending stream gauge records and providing a long-term context for evaluating recent droughts and low-frequency hydroclimatic variability.When extended records of streamflow are incorporated into models, the performance of water supply systems can be tested using a broader range of values and a richer sequence of flows than are contained in gauge records.

One motivation for using tree-ring records has been the recent widespread drought and questions regarding how

persistent and severe droughts were in centuries before gauged flow data were available. By using tree-ring data, we can expand our capability to assess the true potential and risks of future severe drought in the Southwest.

A principal challenge to more widepsread use of tree-ring data for water resources planning has been integrating the data into a typical modeling environment. Tree-ring data are in the form of annual time steps from specific locations, whereas models require daily or monthly time steps from multiple locations.

Several technical training workshops have been held over the past year in Arizona and Colorado to teach water managers and consultants about the methods used to reconstruct hydrology from tree rings, including field and laboratory methods, data processing, statistical calibration techniques, and application approaches. The workshops were designed to provide participants a better basis of understanding from which they might apply tree-ring data in their own water resources planning. Most recently, a number of water resource professionals convened at a May meeting at the University of Colorado in Boulder to share their experiences.

Who’s Using Tree Rings?

Denver Water used tree-ring-derived flow reconstructions of two key gauges to help model the yield of its system under a broader range of conditions than those seen in the utility’s 45-year model period (1947-1991). The results showed that a four-year drought such as one that occurred in the mid-1800s would reduce water supplies to the level of the system’s strategic reserves, even with progressive restrictions on water use.

The City of Boulder and its consultants extended a 95-year stream-gauge record using a 300-year record of tree-ring hydrology. These data were used to develop a drought plan based on the climatic and hydrological effects of past droughts on the city’s water

supply. The work is being expanded to incorporate tree-ring-based temperature and precipitation reconstructions to examine what might happen if the droughts of the past occurred again under warmer and drier conditions.

The U.S. Bureau of Reclamation used a 500-year tree-ring reconstruction of Colorado River flow at Lees Ferry for modeling done in conjunction with the development of shortage criteria and coordinated operations for Lake Powell and Lake Mead. Reclamation’s approach extracted information on the state of the system in a given year—whether the flows were above or below average—from the tree-ring record, and then assigned a specific flow magnitude for that year based on the observed (stream gauge) flow record to generate a set of 500 60-year flow simulations. Not surprisingly, using information from the longer tree-ring record generated a greater probability of system shortages than when models were run using only the observed record.

Salt River Project and the University of Arizona used tree-ring data to investigate how often droughts occur simultaneously in the Upper Colorado River Basin and the Salt-Verde-Tonto river basins. The results showed that synchronous low-flow years are common, thus surpluses in one basin would not be a reliable buffer for shortages in the other. Furthermore, low-flow years tend to cluster in time, heightening the stress on water resources.

Additional water providers present at the Boulder meeting who are interested in incorporating tree-ring data into future planning include Western Area Power Administration, Colorado Springs Utilities, and the Colorado cities of Aurora, Colorado Springs, Pueblo, and Thornton.

More information can be found on the University of Colorado Western Water Assessment web page, Tree-Ring Reconstructions of Streamflow for Water Management in the West (wwa.colorado.edu/resources/paleo/). Contact Connie Woodhouse at [email protected].

ON THE GROUND

Upcoming Conferences

43rd AWRA Annual WaterResources Conference

Embassy Suites Hotel * Albuquerque, NMNovember 12-15, 2007

For the best rate register by Oct. 22, 2007

2008 Spring Specialty ConferenceGIS & Water Resources V

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2008 Summer Specialty ConferenceRiparian Ecosystems & Buffers:Working at the Water’s Edge

Founder’s Inn & Spa * Virginia Beach, VAJune 30 – July 2, 2008Mark Your Calendar

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American Water Resources Association4 West Federal St., P.O. Box 1626Middleburg, VA 20118-1626

Ph: 540.687.8390 FAX: 540.687.8395Questions? [email protected]



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September/October 2007 • Southwest Hydrology • 9

ON THE GROUND (continued)

Urban-Scale Climate Change Effects on Water Use

Anthony Brazel and Patricia Gober – School of Geographical Sciences and Decision Center for a Desert City, Arizona State University

Global climate change is not the only climate-related issue with far-reaching regional consequences. Urban-scale climate change can complicate global climate change scenarios and affect local water use. Urban effects are especially significant in the Southwest where most of the population lives in large, rapidly growing urban areas.

Global climate affects water use in metropolitan regions, but these impacts may be compounded by local-scale climatic processes. One example is the well-known heat island effect, the tendency for urban surfaces to absorb heat during the day and release it at night, leading to higher nighttime temperatures in the urban core than in the surrounding rural countryside.

Recent research at the Decision Center for a Desert City at Arizona State University’s Global Institute for Sustainability has focused on the interrelationships among water, climate, and growth in metropolitan Phoenix.

Long-Term Trends

Balling and Gober (in press) related temperature, precipitation, and the Palmer Hydrological Drought Index (PHDI) to annual variations in per capita water use in Phoenix. As shown in the chart below, from 1980 to 2004, water use declined 15 percent overall to 835 liters per capita per day (pcpd), a trend likely associated with the city’s conservation plan. The authors found an upward trend in temperature of 0.03ºC per year that reflects both regional warming and urban heat island effects associated with urbanized portions of the city. Precipitation decreased by 3.81 millimeters (mm) per year. The PHDI shows a slight trend toward drought during the period.

Short-Term Responses

Next, the residual values of the regression line of per capita water use over time were studied to reveal short-term, city-wide responses to climate variables. Residual values showed that for every 1ºC increase (or decrease) in temperature over the short term, residential water use increases (or decreases) by 60.76 liters pcpd. Yet a reduction of 10 mm per year in precipitation increases water use by only 4 liters pcpd. These results suggest that residential water use is relatively insensitive to climate

variation. The finding was somewhat surprising considering two-thirds of all water use is for outdoor purposes, but reinforces the fact that water use is inherently a human-dominated activity, and residential water often is delivered outdoors by automated irrigation systems that are reset only seasonally if at all.

Variability Between Neighborhoods

Guhathakurta and Gober (in press) explored the effects of urban temperature differences across census tracts in Phoenix on residential water use. The authors found that census tracts that are 1ºC warmer use 1,976 liters (522 gallons) of additional water per month for a typical single-family home (about 49 liters pcpd). The results also suggest that urban heat island-related rises in water demand should be considered by planners as they evaluate environmental consequences of growth strategies such as infill and more compact forms of urban development. More compact cities may reduce the demand for water for outdoor purposes, but increase the demand due to urban heat island effects.

Wentz and Gober (2007) researched the determinants of variability of water use for single-family residences in Phoenix. The addition of new household members and pools, as well as differing lot sizes and landscaping methods, had varying effects on water use in different parts of the city. After accounting for the main indicators of indoor and outdoor water use, the researchers identified a “neighborhood effect”—households in one tract used a similar amount of water as those in neighboring tracts.

New Directions for Planners

Additional atmospheric modeling studies will determine the effects of evapotranspiration (ET), evaporation, soil moisture, and temperature on water use at the local scale for a variety of variables. Initial analyses suggest that over 30 percent of the combined ET and evaporation can occur post-sundown when the heat island is at

City of Phoenix per capita water use (liters per day) shows a trend of 15 percent decline from 1980 to 2004.

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Year

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750

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900

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a maximum. A deeper understanding of climate, water, and urban growth relationships is key to understanding how best to plan for more sustainable urban growth in the Southwest.

This material cited from DCDC is based on work supported by the National Science Foundation under Grant No. SES-0345945 Decision Center for a Desert City (DCDC). Any opinions, findings, or conclusions and recommendations expressed in this material are those of the authors and do not necessarily represent those of the National Science Foundation. Contact Anthony Brazel at [email protected].

ReferencesBalling, R.C., Jr., and P. Gober. Climate variability

and residential water use in Phoenix, Arizona. Journal of Applied Meteorology and Climatology, in press.

Guhathakurta, S., and P. Gober. The impact of urban heat islands on water use: The case of Phoenix metropolitan area. Journal of the American Planning Association, in press.

Wentz, E.A., and P. Gober, 2007. Determinants of small-area water consumption for the City of Phoenix, Arizona. Water Resources Management, www.springerlink.com/content/7082mg44u7851351/fulltext.pdf


EPA Issues Determination on 11 Contaminants, Punts on Two Biggies

Last spring, the U.S. Environmental Protection Agency issued a preliminary determination not to regulate 11 contaminants on its second drinking water contaminant candidate list (CCL), concluding they do not occur at levels of public health concern in public water systems. A regulatory determination is a formal decision on whether EPA should develop a national primary drinking water regulation for a specific contaminant. The Safe Drinking Water Act requires EPA every five years to select at least five contaminants from the most recent CCL to determine whether or not to regulate them. In 2005, the agency published the second CCL of 51 contaminants.

The 11 contaminants that will not be regulated are: boron (a naturally occurring substance); dacthal mono- and di-acid

degradates (herbicides); 1,1-dichloro-2,2-bis (p-chlorophenyl) ethylene (a degradate of DDT); 1,3-dichloropropene (Telone, a soil fumigant); 2,4-dinitrotoluene and 2,6-dinitrotoluene (in ammunition, explosives, dyes, polyurethane foams, and automobile air bags); s-ethyl propyl thiocarbamate and Terbacil (herbicides); Fonofos (soil insecticide); and 1,1,2,2-tetrachloroethane (volatile organic compound).

EPA determined that two other contaminants—perchlorate and MTBE—require additional investigation to ascertain total human exposure and health risks. This outraged many who have been arguing for years for safety standards for these controversial compounds.

U.S. Senator Barbara Boxer, chair of the Senate Environment and Public Works Committee, issued a statement saying, “It is simply unacceptable that EPA would postpone, yet again, a decision on whether to protect our children and families from the dangerous chemical perchlorate. Just last December EPA discontinued

testing for perchlorate in tap water. I am outraged that EPA has yet again refused to do its duty to protect the health of our families and communities from perchlorate pollution. I have introduced two bills on perchlorate—one to require testing and public disclosure of contamination, the other ordering EPA to quickly set a standard. It is clear that action is needed.”

The Natural Resources Defense Council accused EPA of “abdicating its responsibility once more,” stating that numerous data already exist regarding measurable perchlorate concentrations in human and cow milk, food items, and human urine, and on the risks of exposure.

Visit www.epa.gov/safewater/ccl/reg_determine2.html, boxer.senate.gov, and www.nrdc.org.

Texas Legislators Pass Major Water Bill

In late May, Texas legislators passed Senate Bill 3 providing for the development, management, and preservation of the state’s water resources. It was the state’s first major water-planning bill in a decade, according to the Dallas News. A key aspect of the bill is its provision for “environmental flows” designed to protect fish, wildlife, and wetlands in streams, estuaries, and bays. It establishes a basin-by-basin process for developing recommendations to meet instream needs and directs the Texas Commission on Environmental Quality (TCEQ) to establish environmental flow standards to be used in subsequent water rights allocations.

SB3 also provides for the establishment of water conservation and planning programs, requiring public water providers serving greater than 3,300 connections to prepare water conservation plans, and mandating the implementation of a state water conservation public awareness program. Funding for water supply projects is to be allocated with priority to entities that either have achieved or will achieve significant water conservation savings.

GOVERNMENT

HydroFactsWATER FOR ENERGY

Total daily water withdrawals for coal and gas steam-generating electric plants in the Interior West:over 650 million gallons (2,000 acre-feet)

Water consumed per kilowatt-hour generated varies greatly with type of plant and its elevation:

Typical case:coal-burning power plants use on average 0.50 gallons

Worst case:thermonuclear plant located in low desert uses 0.70 - 0.90 gallons

Best case:new natural gas plants use about 0.30 gallons

Future case:dry cooling systems (now used in over 50 plants) use 0 gallons

ENERGY FOR WATER

Percent of natural gas used in California associated with the use of water: 20

Percent of electricity used on western farms to pump groundwater: 90

Rank of water sources by energy intensity (from low to high):

• local surface water• reuse of water• local groundwater• imported surface or groundwater


In addition, SB3 provides for the designation of unique reservoir sites; the designation expires in 2015 if development of the reservoirs has not yet begun. Environmental groups opposed to new reservoirs proposed in the state’s 2007 water plan pointed out that SB3 merely designates certain sites as having unique value for reservoirs and does not in any way provide for their construction. The same article of the bill also allows designation of sites of ecological value, again following on recommendations of the 2007 state water plan.

Finally, the bill authorizes higher pumping limits from the Edwards Aquifer Authority, in an attempt to resolve earlier legislation that permitted fewer water rights than had already been allocated.

The bill was signed by Governor Rick Perry in June.

Visit www.capitol.state.tx.us and www.dallasnews.com.

New Policies to Facilitate Voluntary Mine Cleanup

In June, U.S. EPA issued new policies designed to reduce barriers under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) for public and private entities to voluntarily clean up abandoned hardrock mine sites responsible for degrading water quality. Under the new policies, EPA and volunteer parties will be able to enter into “Good Samaritan Settlement Agreements” that provide key legal protections to good samaritans as nonliable parties, including a federal covenant not to sue under CERCLA and protection from third-party contribution suits.

About half a million orphan mines exist in the United States, most of them hardrock mines in the West. In many cases, the parties responsible for pollution from orphan mine sites no longer exist or are not financially viable. Yet, a variety of interests, ranging from nonprofit organizations to

state and local governments, are willing to voluntarily clean up these abandoned sites. Prior to these new policies, however, many proposed cleanup projects were thwarted by volunteers’ concerns of being held liable under the Clean Water Act and CERCLA.

EPA acknowledges that voluntary cleanups facilitated under the new policies likely will not solve all the problems at abandoned mines, but the agency encourages incremental improvements that benefit the ecosystems impacted by these mines.

Visit www.epa.gov/compliance/resources/publications/cleanup/superfund/factsheet/goodsam-tools-fs.html.

New Federal Wetland Guidance Issued

In June, the U.S. EPA and the U.S. Army Corps of Engineers issued joint guidance for their field offices designed to clarify circumstances when a Clean Water Act (CWA) Section 404 permit is needed before conducting activities in wetlands, tributaries, and other waters. The guidance was developed following last year’s Supreme Court split decision regarding the scope of the agencies’ jurisdiction under the CWA. The split decision resulted in the ninth judge, Anthony Kennedy, stating that decisions on how the CWA applies to smaller water bodies must be made in the lower courts on a case-by-case basis.

To help make that determination, the guidance discusses the agencies’ protection of three classes of waters through the following actions:

• Continuing to regulate “traditionally navigable waters,” including all rivers and other waters that are large enough to be used by boats that transport commerce and any wetlands adjacent to such waters;

• Continuing to regulate “non-navigable tributaries that are relatively permanent and wetlands that are physically connected to these tributaries”; and

• Continuing to regulate other tributaries and adjacent wetlands that have

certain characteristics that significantly affect traditionally navigable waters, on a case-by-case basis.

Critics said the new guidance is still not clear on exactly how to protect surface waters, may eliminate protection for many streams, and likely will result in many lawsuits, reported Reuters.

During the first six months the guidance is implemented, the public is invited to comment on their experiences applying the guidance and to offer case studies. The agencies will broadly consider jurisdictional issues, including additional clarification and definition of key terminology, through rulemaking or other appropriate policy practice.

Comments can be submitted to docket EPA-HQ-OW-2007-0282 through www.regulations.gov/fdmspublic/component/main.

continued on next page

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GOVERNMENT (continued)

Tiny Fish Wields Big Power in the Delta

The three-inch-long endangered delta smelt (Hypomesus transpacificus) is causing great turmoil in California’s State Water Project (SWP). In recent years, the populations of smelt and some other fish species have been markedly declining, and scientists warned that large pumps drawing water out of the Sacramento-San Joaquin Delta for transport to 25 million people and 750 million acres of farmland in Southern California are largely to blame, sucking in and killing large amounts of the fish, particularly juveniles.

Last year, the issue came under greater focus as federal water agencies requested revisions to endangered species permits that would allow pumping despite the loss of certain numbers of fish. But in March, Alameda Superior Court Judge Frank Roesch ruled that the California Department of Water Resources (DWR) must comply with the state’s more strict endangered species act or face shutdown of the pumps. DWR continued working to get federal endangered species permits rewritten and then endorsed by state wildlife regulators.

Before any new permits were issued, however, new information came out about a severe decline of the young smelt, along with evidence that many were being entrained by the pumps, and DWR voluntarily ceased pumping on May 31. In his announcement, DWR Director Lester Snow pointed out that many factors affect the smelt population, including invasive species, toxins, and diversions by other users besides SWP, and challenged other public agencies to take aggressive actions to protect the species. The U.S. Bureau of Reclamation also runs part of its Central Valley Project water supply through the delta, and drastically reduced its pumping during that time. The shutdown lasted 10 days, until the young smelt migrated out of the pump area to cooler waters.

The shutdown was closely monitored by downstream water users, but reservoirs were generally full enough and the shutdown sufficiently brief that no crises ensued.

On June 10, DWR began to gradually resume pumping, beginning at just 10 percent of its normal rate and reaching normal pumping rates by the end of the month. On June 22, U.S. District Judge Oliver Wanger ruled “there was insufficient evidence to indicate that current pumping operations in the … Delta jeopardize the continued existence of the tiny delta smelt,” reported the San Francisco Chronicle.

Over the summer, the saga continued. In early July, DWR began to switch off the pumps at night, hoping to avoid smelt attrition without significantly impacting water deliveries. According to a July 6 article in the San Jose Mercury News, more than 600 smelt were killed in the pumps in the first week of July, but in the 3 days that the pumps were off at night, no more than 21 died each day.

The status of the delta ecosystem as a whole, as reflected by the plight of the smelt in particular, is the subject of much attention in California by everyone from environmental groups to the governor. All seem to agree that the delta needs rescuing, and many proposals are being put forth to accomplish that, but given the large numbers of parties that have a stake in the delta, finding an agreeable, effective solution will be a challenge.

Visit www.water.ca.gov, www.sfgate.com, and www.mercurynews.com.

Reclamation Completes Yuma Desalter Test

From March through May, the U.S. Bureau of Reclamation performed a 90-day test of the Yuma Desalting Plant, located on the Colorado River just north of the U.S.-Mexico border. The plant was run at one-tenth capacity to gather data on the potential costs of operating the plant and determine whether design

deficiencies revealed during earlier tests have been resolved. In addition, University of Arizona researchers monitored water quality in the downstream cienega during the test run to help assess potential environmental impacts of operating the plant. Scientists are concerned that running the desalting plant will significantly reduce flow to the cienega and concurrently increase its salinity levels, severely impacting the ecosystem that has developed there.

Construction of the plant was completed in 1993 at a cost of about $245 million. It can produce up to 72 million gallons of desalted water per day, and was built to help meet salinity requirements for Colorado River water delivered to Mexico and to salvage saline irrigation drainage water for beneficial use. However, the plant has never been operated other than for an initial six-month test because water storage in the Colorado River reservoirs has been adequate to meet all water quantity and quality requirements. With the droughts of recent years threatening water shortages in the Colorado River Basin, however, interest in the plant has been renewed.

According to the Yuma Sun, Reclamation officials said the plant performed better than expected during the recent test, producing more than 4,000 acre-feet of water that was discharged into the river, and successfully incorporating new, more efficient technology. The cost of the test run was not immediately available because additional shut-down activities had to be factored into it. Likewise, water quality results have not yet been released.

Visit www.yumasun.com and www.usbr.gov/lc/region.

Salton Sea Restoration Plan Selected

After reviewing extensive comments on nine different proposals presented in an October 2006 draft Salton Sea Restoration Report, the California Resources Agency announced in May its preferred alternative


for restoring the sea. Secretary for Resources Mike Chrisman then presented the plan to the state legislature for approval and funding.

The process to restore the Salton Sea began in 2003 with the Quantification Settlement Agreement to reduce southern California’s dependence on Colorado River water. Under terms of the agreement, inflows to the Salton Sea will be reduced, hastening its ecological degradation. To mitigate these effects, state legislation established a Salton Sea Advisory Committee to help guide the secretary in determining the best restoration and mitigation plan for the next 75 years. The Salton Sea Restoration Act and related legislation required that the preferred alternative be the one that will best restore the long-term stable aquatic and shoreline habitat to historic levels and promote diversity of fish and wildlife that depend on the Salton Sea, eliminate air-quality impacts from restoration activities, and protect water quality.

According to the Palm Springs Desert Sun, the chosen alternative—with an $8.9 million price tag—subdivides the existing sea into a wildlife habitat in one area and a recreational lake in another. The final footprint of the sea will be one-fifth of its current area, meaning much of the lakebed will become exposed.

Strong opposition to the plan immediately arose from the Torres Martinez Desert Cahuilla Indians and environmental groups, who said the large amounts of lake bed that would be exposed under the plan would create significant air quality problems, reported the Desert Sun.

In June, the California Senate passed SB187, establishing the Salton Sea Restoration Fund and allocating $47 million for initial restoration activities. The bill then moved to the Assembly, where committees were expected to work on details.

Visit info.sen.ca.gov, www.thedesertsun.com The University of Arizona -- EEO/AA - M/W/D/V

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It’s not a secret, but most people don’t think about it. Water uses a tremendous amount of energy. It is not just a

matter of the gas and electricity required to heat, cool, or pump water in our homes and businesses. It takes large amounts of energy before that to extract, convey, treat, and deliver water. Additional energy is required to collect, treat, and dispose of wastewater. While the total energy required for water use is highly location-specific, overall, the California Energy Commission (CEC) has estimated that almost 20 percent of California’s electricity demand, and over 30 percent of California’s natural gas demand, are associated with water use.

Energy in the Water Use CycleEnergy is used at five stages of the water use cycle:

Extracting and conveying water: Most water used in the United States is diverted from rivers and streams or pumped from aquifers. Conveying water often means pumping it over hills or into storage facilities—a process that can be highly energy intensive. Smaller amounts of fresh water are extracted from salt, brackish, or recycled water using desalination or other energy-consuming technologies.

Treating water: Water treatment facilities use energy to pump and process water, and this energy demand is expected to increase over the next decade as treatment capacity expands, new water

quality standards are adopted, and new treatments are developed to improve the taste and color of drinking water.

Distributing water: Energy is usually needed to pump and pressurize water, but gravity pressurization and distribution are possible when reservoirs are sufficiently higher than the locations of water use.

Using water: End users consume additional energy by treating water with softeners or filters, circulating and pressurizing water with circulation pumps and irrigation systems, and heating and cooling water.

Collecting and treating wastewater: Energy is used to pump wastewater to the treatment plant, and to aerate and filter it at the plant. On average, wastewater treatment in California uses 500 to 1,500 kilowatt-hours per acre-foot.

Water Options from an

Energy PerspectiveTo keep up with growing demand, water agencies are seeking new sources—generally a mix of surface water, groundwater, recycled water, and desalinated water. How do these

alternatives compare when their energy costs are considered?

Surface water: The energy intensity of surface water depends on the source and destination of the water. In much of the West, water is pumped over long distances. Delivering water from Northern to Southern California, for example, requires 3,000 kilowatt hours per acre-foot, because the water is pumped over the 2,000-foot Tehachapi Mountains—the highest lift of any water system in the world. But even gravity-fed water is frequently pumped into and out of reservoirs.

Groundwater: The energy required to extract and deliver groundwater depends on the depth to groundwater and the efficiency of the pumps. In California, energy demands for groundwater pumping range from an average of 292 kilowatt-hours per acre-foot along California’s central coast to 740 kilowatt-hours per acre-foot for the Westlands Water District in the Central Valley.

Recycled water: The CEC estimates that the energy required for water recycling—additional treatment of wastewater and transport to the point of use—ranges in California from 325 to 1,000 kilowatt-hours per acre-foot. Depending on the energy costs for surface or groundwater supplies in a certain area, water recycling may be an energy-efficient alternative.

Using water more efficiently might be the single best way to reduce water-related energy costs.

THE WATER-ENERGY

Ronnie Cohen – Natural Resources Defense Council

NN•EE•XX•UU•SS


Orange County, California, is constructing a water-recycling system that will use half the energy required to import the same amount of water from Northern California. The project will produce 70 million gallons of water per day for less than the cost of imported water, and save an estimated 140 million kilowatt-hours annually.

Desalinated water: Desalination has been limited in the United States because of its high cost, directly tied to high energy consumption: energy accounts for approximately 40 percent of total desalination costs. The amount varies widely depending on the method used and the quality of the source water. Estimates of energy demand for seawater desalination plants proposed or planned in California range from about 4,400 to 5,500 kilowatt-hours per acre-foot. Desalination of brackish groundwater may require less energy; two such facilities in Southern California require just 405 and 1,700 kilowatt-hours per acre-foot.

Efficiency As a Water SourceForward-thinking water agencies are also considering efficient use as an “alternative” source of water. These agencies compare efficiency or “demand-side” alternatives to traditional supply-side alternatives for meeting a community’s future water needs.

A recent analysis by the Natural Resources Defense Council (NRDC) and the Pacific Institute found that for the San Diego

region, end use represents the single largest component of water-related energy costs. If this is true for regions like San Diego, where the energy cost of conveyance is unusally high, it is likely to be even truer for other regions, suggesting potentially enormous energy savings from using water more efficiently.

Residential water use accounts for 50 percent to 85 percent of urban water use. Using water more efficiently may be the single best way to reduce water-related energy costs, because, in addition to saving the on-site energy, efficiency reduces the upstream energy required to extract, convey, treat, and distribute

water, as well as the downstream energy needed to treat and dispose of wastewater.

Efficiency measures that reduce indoor water use include installing efficient toilets, showerheads, dishwashers, and clothes washers. Outdoor landscape irrigation, which typically does not require end-use energy nor wastewater treatment, is still a highly promising area for reducing water and energy use, due to the sheer magnitude of water required for landscape use. More than 50 percent of residential use goes to landscape irrigation. This percentage may be even higher in hot, inland areas. According to the CEC, the cumulative energy consumed for outdoor water use (including conveyance, treatment, and distribution) averages 3,500 kilowatt-hours per acre-foot in Northern California and over 11,000 kilowatt-hours per acre-foot in Southern California. Recently, water agencies have begun to focus conservation programs on outdoor use, using such tools as “smart” controllers that adjust landscape irrigation based on weather conditions.

Agencies Taking StridesWater agencies and energy utilities alike are becoming more aware of the energy-water connection, implementing ways to reduce energy and water consumption.

The Inland Empire Utilities Agency of Southern California adopted an integrated water management strategy to reduce dependence on high-energy water supplies by establishing aggressive efficient-use programs and developing water-recycling and groundwater- and stormwater-recapture programs. The water-recycling program is expected to produce approximately 100,000 acre-feet per year, replacing the same amount of imported water and saving 34 megawatts of electricity a year.

A recent CEC report suggested that conserving water might be a more cost-efficient approach for energy utilities to save energy than traditional programs. Preliminary estimates showed that by conserving water, California could save 95 percent of the energy saved by implementing the usual energy efficiency programs at only 58 percent of the cost.

Putting Kilowatt-Hours into Perspective

A kilowatt-hour (kWh) is a unit of energy

(power used over time) commonly used

with electricity and natural gas. A 100-

watt lightbulb left on for 10 hours will

consume one kWh of electricity.

According to the U.S. Department of

Energy, the average household in the

West used 8,300 kilowatt-hours of

electricity per year in 2001. Average

2001 electrical consumption for

common items includes:

• Refrigerator: 1,239 kWh/year

• Personal computer: 300 kWh/year

• Color TV: 137 kWh/year

• Coffee maker: 116 kWh/year

A typical 10 million-gallon-per-day

surface water treatment plant consumes

close to 15,000 kWh per day.

The U.S. water and wastewater sector

annually consumes around 75 billion

kWh.

The average retail price of residential

electricity in 2007 is about $0.10/kWh.

Commercial and industrial prices are

slightly less.

see Nexus, page 19

Just the Numbers: Energy Consumed

for CA Water(all in kilowatt-hours per acre-foot)

• Transport from Northern to Southern

California: 3,000

• Groundwater pumping, Central

Coast: 292

• Groundwater pumping, Central

Valley: 740

• Planned seawater desalination: 4,400

to 5,500

• Existing brackish water desalination:

405 and 1,700

• Wastewater treatment: 500-1,500

• Water recycling: 325-1,000

• Outdoor water use, Northern

California: 3,500

• Outdoor water use, Southern

California: more than 11,000


Energy Element Water Quantity Connection Water Quality Connection

Ener

gy E

xtra

ctio

n

& P

rodu

ctio

n

Oil and gas exploration Water used for drilling, completion, and fracturing

Shallow groundwater quality impacted

Oil and gas production Large volume of impaired water produced

Produced water can impact surface and groundwater quality

Coal and uranium mining Large quantities of water may be produced

Tailings and drainage can impact surface water and groundwater

Ele

ctri

c P

ower

G

ener

atio

n

Thermoelectric(fossil, biomass, nuclear)

Surface water and groundwater used for cooling and scrubbing

Thermal and air emissions impact surface waters and ecology

Hydroelectric Reservoirs lose large quantities of water to evaporation

Water temperatures, quality, ecology can be impacted

Solar photovoltaic and wind Only minimal water used for panel and blade washing

NoneR

efi n

ing

&

Pro

cess

ing Traditional oil and gas refi ning Water used to refi ne oil and gas End use can impact water quality

Biofuels and ethanol Water used in growing and refi ning Wastewater requires treatment

Synfuels and hydrogen Water for synthesis or steam reforming

Wastewater requires treatment

En

erg

y Tr

ansp

orta

tion

& S

tora

ge

Energy pipelines Water used in hydrostatic testing Wastewater requires treatment

Coal slurry pipelines Water used for slurry transport and not returned

Final water is of poor quality and requires treatment

Barge transport of energy Fuel delivery is impacted by river fl ows and stages

Spills or accidents can impact water quaity

Oil and gas storage caverns Large quantities of water required for slurry mining of caverns

Slurry disposal impacts water quality and ecology

In response to a 2004 congressional directive, the U.S. Department of Energy (DOE) prepared a report

to Congress on the interdependency of energy and water in the United States. As illustrated in the table at right, water is an integral element of energy resource and development.

The report, released earlier this year, has a national to regional focus and notes that much of the growth in electricity demand over the next 25 years is projected to occur in areas such as the Southwest where water supplies are already limited. Technologies are available that can reduce water use, such as wind and solar power, but economics, among other factors, have limited their deployment so far.

Managers and policy makers must now consider energy and water development so that each resource is used according to its full value. The chart at right shows water consumption for various stages of energy production, a consideration that will become increasingly important as new energy sources are developed.

What is the federal role in this issue? According to the report, federal agencies need to foster greater collaboration among federal, regional, and state agencies and with industry and other stakeholders. Science- and system-based policies are needed to ensure that regulations developed to support one area, such as greater domestic energy supplies, do not have unintended negative impacts on water resources or water quality. Finally, infrastructure synergies should be maximized to promote conservation of both energy and water.

The 80-page report,“Energy Demands on Water Resources: Report to Congress on the Interdependency of Energy and Water,” prepared by Sandia National Laboratory with support from the National Energy Technology Laboratory and Los Alamos National Laboratory, is available at www.sandia.gov/energy-water/docs/121-RptToCongress-EWwEIAcomments-FINAL.pdf.

ENERGY DEMANDS ON WATER RESOURCES:The Federal Perspective

Connections between the energy sector and water availability and quantity (from the Report to Congress on the Interdependency of Energy and Water).

Water consumption for various types of energy extraction, processing, storage, and transport (modified from the Report to Congress on the Interdependency of Energy and Water).

Betsy Woodhouse – Southwest Hydrology, University of Arizona

gallons/kilowatt-hour

*Water Consumption for Electric Power from Evaporatively-Cooled Combined Cycle Gas Turbine

**One-Time Use for Solution Mining of Salt Cavern

Biodiesel Refining

Soy Irrigation

Ethanol Processing

Corn Irrigation

Hydrogen Electrolysis

Hydrogen Reforming

Uranium Processing

Uranium Mining

Oil Storage in Salt Cavern**

Oil Sands

Oil Shale In-Situ*

Oil Shale Surface Retort

Refining

Enhanced Oil Recovery

Petroleum Extraction

Gas Storage in Salt Cavern**

Natural Gas Pipeline Operations

Natural Gas Extraction & Processing

Coal Gasification

Coal Slurry

Coal Liquefaction

Coal Washing

Coal Mining

0.001 0.01 0.1 1 10 100 1000


Climate ConcernsAny evaluation of new water supplies or re-examination of existing supplies must factor in the predicted impacts of climate change. The most energy-conserving approaches—efficient-use programs and recycling—are also likely to be the best performers in the uncertain conditions created by climate change. Water conservation and recycling can help water agencies meet the demand for water under a variety of climate change scenarios, while simultaneously saving them energy and reducing the emissions that contribute to climate change.

As the water-energy nexus gains attention, more people will recognize the role that improved conservation, recycling, and other water management alternatives can play in saving energy. When it comes to saving energy, turning off the tap is like turning off the lights.

This article is summarized from an article in Home Energy’s Special Issue on Water/Energy, 2007. See www.homeenergy.org. Contact Ronnie Cohen at [email protected].

Nexus, continued from page 17

It’s a Southwest necessity.Together we can attain it.

• Groundwater resource evaluation and basin inventory analysis• Modeling of groundwater and surface water flow systems• Wellhead and aquifer source protection• Assured water supply planning and development• Litigation support for water rights and resource damage• Water quality evaluation and treatment (including arsenic)

For more information, contact Brad Cross at 480.905.9311 or via e-mail at [email protected].

LFR Inc. is an environmental management & consulting engineering firm with 29 offices nationwide. For more information, call 800.320.1028 or visit us at www.lfr.com.


Water and energy are inextricably linked. Large amounts of water are

needed for energy production, and large amounts of energy are needed for the extraction, conveyance, treatment, and distribution of water. Historically, energy and water issues have been examined independently, which has led to:

• planning for future electricity production without considering water needs; and

• planning for a future domestic potable water supply and wastewater treatment with the assumption that electricity will be readily available and affordable.

In the future, however, both the scarcity of freshwater and the cost of energy will likely become limiting factors of economic and population growth. This is particularly critical in California and other arid Southwestern states, where population is projected to grow dramatically and climate change models suggest that freshwater supplies may decrease significantly. Integrated planning between the energy and water sectors therefore will be essential to meet rising demands for both resources.

How Much Water for Electricity?We reviewed peer-reviewed literature, industry and government sources, and primary research to collect quantitative water requirements pertaining to each step of the electricity generation process. The water input steps considered were different for each type of generation but generally included agriculture, mining, transportation, makeup water, processing, cooling, cleaning, evaporative losses, and other. For example, water is required at several points in the process of generating electricity from coal. Initially, water is required for extraction (mining), processing (washing), fuel conversion (gasification), and finally cooling.

The following primary energy sources were analyzed: bioenergy, coal, geothermal, hydroelectric, natural gas, nuclear, oil, solar, and wind. High and low estimates for both water withdrawn and water consumed were included in the data collection process. To ensure the validity of the data, the 2005 water withdrawals for electricity generation

were projected for four counties in California and compared to U.S. Geological Survey (USGS) and California Department of Water Resources (DWR) thermoelectric water withdrawal estimates for the same counties. Projected water requirements closely agreed with USGS and DWR values for coastal counties. The projection for the one inland county showed some discrepancy, likely due to the large amount of reclaimed water used for power plant cooling there.

The data were used to project the total water needs for California’s potential future energy portfolios under the 2010 and 2020 renewable portfolio standards (RPS; see sidebar below). In addition, scenarios were created for the year 2020 that altered the primary energy sources, electricity generation technologies, and cooling technologies. These scenarios included: 1) a fossil fuel-focused scenario in which future electrical generation growth was limited to natural gas and coal; 2) an advanced technologies scenario in which integrated gasification combined cycle (IGCC) and dry cooling technologies were applied to the 2020 RPS portfolio; and 3) a water-efficient primary energy scenario that relies on the primary energy sources that our initial research identified as water-efficient (rooftop solar photovoltaic, wind, and waste-based bioenergy).

This analysis considered only freshwater requirements for power generation, thus seawater-cooled thermoelectric power plants and hydroelectric facilities were excluded. Although the total volume of seawater withdrawn for power generation in California is far greater than that for freshwater, greater competition exists

While geothermal and coal constitute less than a quarter of the generation capacity …, they account for almost 90 percent of the freshwater requirements.

California’s Energy-Water Nexus:Water Use in Electricity Generation

Dana Larson, Cheryl Lee, Stacy Tellinghuisen, and Arturo Keller — Bren School of Environmental Management and Science, University of California, Santa Barbara

Renewable Portfolio StandardsTo promote sustainable energy production

and help boost the renewables market

as it matures, 24 states to date have

adopted renewable portfolio standards

(RPS). These require sellers of electricity

to have a certain percentage of

“renewable power” in their mix. RPS

policies usually mandate a gradual

increase in the percentage over a number

of years, and often involve a trading

mechanism whereby companies can sell

credits to those who haven’t met their

requirements.

Renewable energy sources typically

include wind, geothermal, biomass, solar,

hydropower, and ocean-based energy

(using offshore wind, ocean waves,

currents, or tides).

The California RPS policy, the most

stringent in the United States, was

established in 2002, requiring retail

sellers of electricity to purchase

20 percent of their electricity from

renewable resources by 2017. Because

the state had already been generating

around 10 percent of its electricity

consumption by renewables and

the program enjoyed considerable

early success, the time frame was

accelerated to achieve the 20 percent

goal by 2010, and a new goal of 33

percent was set for 2020.


for freshwater resources. Further, while seawater cooling may appear to be a likely alternative to the use of freshwater in energy generation, growing concerns about negative impacts to coastal ecosystems have shifted interest away from this cooling method.

And the Results Are...Water requirements vary greatly, depending on the primary energy source, conversion technologies, and cooling technologies used (see figure, right). Overall, the data showed that the biggest water users are bioenergy derived from dedicated energy crops (based on average values for irrigated crops), hydroelectric facilities, and thermoelectric facilities using once-through cooling. Waste-based bioenergy, thermoelectric facilities using dry cooling, solar photovoltaics, and wind turbines require the least water.

Alternative Energy ScenariosWhen the water requirements were applied to future energy scenarios, the total amount of water required varied (see figure below right). Surprisingly, the fossil fuel-based scenario projected for 2020 requires less water than that required by the 2020 RPS. A closer analysis of the breakdown of water use for each of the different energy sources within these two scenarios reveals a large proportional contribution of geothermal and coal. While these two primary energy sources constitute less than a quarter of the generation capacity of the 2020 RPS and fossil fuel based scenarios, they account for almost 90 percent of the freshwater requirements of these scenarios.

Thus, altering the generation and cooling technologies or primary energy sources can decrease freshwater withdrawals and consumption significantly below the 2020 RPS-based projected energy mix. Future water requirements for electrical generation can be reduced, not only below future projections, but even below current water requirements. By incorporating technologies such as dry cooling and coal gasification into the RPS 2020 scenario, California’s projected annual freshwater withdrawal and consumption requirements decrease by 66 percent. By relying on more water-efficient primary energy sources such as solar photovoltaic, wind, and waste-

Average water required (W = withdrawals, C = consumption) for electricity generated in 2005 and for three future (2020) scenarios. Although nuclear and hydropower are included in the portfolios (assumes existing infrastructure will continue to be utilized), they are not considered in the water requirements totals because California’s nuclear plants are seawater cooled and water use by hydroelectric facilities counts all water flowing through turbines, a very different metric than other water requirements for generation.

Water requirements are highest for electricity generated from irrigated crop-based biomass, hydroelectric power, and for thermoelectric generation using once-through cooling technology. Note: not all energy crops are irrigated, and regional irrigation differences are great. CSP = concentrating solar power (power towers and parabolic trough plants).

Average Water Withdrawals (gal/kWh)

Biogas

Waste Products

Dedicated Energy Crops

Dry Cooling

Wet Recirculating Cooling

Once-through Cooling

Dry Cooling

Wet Recirculating Cooling

Once-through Cooling

“Run of River” Facilities

Large Reservoir and Dam

Small Reservoir and Dam

CSP, Dish-Engine System

CSP, Parabolic Troughs

CSP, Power Tower Plant

RV, Rooftop Panels

Medium-sized Farm

Large-sized Farm

0 10 20 30 40 50 60

Water Use for Electricity Production

130+

BIOENERGY

FOSSIL FUELS

GEOTHERMAL

HYDROPOWER

SOLAR

WIND

350

300

250

200

150

100

50

0

Vo

lum

e (

Millio

n m

3)

Freshwater Required for Energy Generation in California

WW C W C C

2005 2020, RPS2020, Fossil Fuel-Based Energy Mix

2020, Water-Efficient Primary

Energy Mix

W C

Coal Geothermal Oil/Gas Solar Wind Bioenergy

ENERGY

PORTFOLIO

Nuclear Hydropower

55% fossil fuels 5% renewables 34% hydro & nuclear 6% geothermal

35% fossil fuels 28% renewables27% hydro & nuclear10% geothermal



see California’s Nexus, page 30


The U.S. ethanol industry is growing at an enormous rate. In 2006, almost 5 billion gallons

of ethanol were produced, an increase of 1 billion gallons over the previous year. At least 73 corn ethanol plants are currently under construction with eight more undergoing expansion, which will add another 6 billion gallons of new capacity by 2009. President Bush in his 2007 State of the Union Address established his “Twenty in Ten” goal of displacing 20 percent of gasoline in 10 years. This equates to 35 billion gallons of renewable and alternative fuels by 2017. With such rapid growth, water availability, utilization, and quality are key issues that must be addressed.

In 2006, the Institute for Agriculture and Trade Policy (IATP) issued a report describing why consumptive water use was one of the most important emerging concerns for the ethanol industry. Conflicts over water use in the Midwest are growing among agricultural processing facilities, livestock operations, and urban areas as water usage by each rises.

The most comprehensive methodology for analyzing and quantifying the water usage for a product such as ethanol is life cycle inventory and assessment (LCA). LCA quantifies material and energy flow rates across the entire life cycle of the fuel from cradle to grave. For ethanol, this includes: crop production and harvesting, transportation, ethanol production, and final utilization in a vehicle engine.

Of these, crop production and ethanol production are the greatest water users.

Water Use in

Crop ProductionThe amount of water required to grow corn depends on local and regional considerations. As much as 96 percent of the field corn used for ethanol production is not irrigated at all. For corn that is irrigated, water consumption estimates are not widely available. The 2003 USDA Farm and Ranch Survey states that irrigated corn grain uses on average 1.2 acre-feet of water per acre of land. The average corn yield from this land is 178 bushels per acre. This equates to 785 gallons of water for every gallon of ethanol produced.

Water Use in Corn

Ethanol ProductionTwo types of ethanol production processes are used in the United States: wet mill and dry grind. Over 80 percent of U.S. ethanol is produced from corn by the dry grind process depicted above. Corn grain is milled, then slurried with water to create “mash.” Enzymes are added to the mash and this mixture is then cooked to hydrolyze the starch into glucose sugars. Yeast ferment these sugars into ethanol and carbon dioxide and the ethanol is purified

through a combination of distillation and molecular sieve dehydration to create fuel ethanol. The byproduct of this process is known as distiller’s dried grains and solubles (DDGS) and is used wet or dry as animal feed.

Many of these ethanol plants have little or no wastewater discharge. They recycle a significant portion of their process water through a combination of centrifuges, evaporation, and anaerobic digestion. Therefore, water demand primarily is related to energy production, specifically the cooling tower and boiler systems.

Estimates of water usage during ethanol production range from 3 to 4 gallons of water per gallon of ethanol produced. IATP (2006) states that Minnesota ethanol plants in 2005 averaged 4.2 gallons of water per gallon of ethanol produced. Other industry experts calculate ratios closer to 3:1. Thus, a 50-million-gallon per year ethanol facility can expect to use 150 to 200 million gallons of water per year, or over 400,000 gallons per day (1.2 acre-feet). In the corn belt, the source of this is often groundwater.

Water Usage for Current and Future Ethanol ProductionAndy Aden – National Renewable Energy Laboratory

corn delivered to plant grinder cooker

C02 scrubber

fermenter

distillation columns

molecular sieve

centrifuge

evaporationsystem

rotary drum dryer

wet stillage or syrup to market

distillers grains to market

thin stillage or syrup to market

ethanol storage

ethanol transported to market

Dry grind corn ethanol production process (modified from Renewable Fuels Association, 2007)


How does this usage compare to other industries and processes? Petroleum refining, for example, has the highest rate of water recycling of any major industry. Water use ranges between 65 and 90 gallons per barrel of crude oil processed and wastewater discharge ranges between 20 and 40 gallons, leaving 45 to 50 gallons of water consumed per barrel, or 2 to 2.5 gallons of water per gallon of gasoline. However, the ratio is lower if all fuel products are considered (diesel, kerosene, etc). Power plants, however, consume significantly more water because they have greater cooling needs. A coal-fired power plant on average will use 9.5 gallons per minute per megawatt (MW). For a 250 MW power plant, that equates to 3.4 million gallons per day. And nuclear power plants use 25 percent more water than an equivalent coal-fired power plant.

Water Use in Cellulosic

Ethanol ProductionCellulosic ethanol technology is also rapidly becoming a reality. At the National Renewable Energy Laboratory (NREL), scientists and engineers continue to research and develop the technology to convert biomass into fuels such as ethanol. Biomass feedstocks range from agricultural residues (corn stover, wheat straw) to woody feedstocks, and include energy crops such as switchgrass, which is more drought tolerant than corn and can be grown over a wider geographic area.

An NREL report (Aden and others, 2002) documents a detailed process design and economic analysis for the conversion of corn stover to ethanol. Similar to corn ethanol production, a combination of enzymes and fermenting organisms are used in this biological approach, but the process is more complex. For example, cellulose is much more difficult to break down. A mixture of sugars is fermented instead of a single sugar, and the presence of the byproduct lignin compounds the technical difficulty of this process. Using this design, 69.3 million gallons per year of ethanol are produced, and 6 gallons of water are used per gallon of ethanol produced. This is a non-optimized process with potential for improvement.

As with corn, most of the water demand is related to energy production.

Similarly, a 2007 NREL report (Phillips and others, 2007) documents a detailed process design and economic analysis for the conversion of wood chips to ethanol via a thermochemical approach, using low pressure gasification followed by mixed alcohol synthesis. However, this report documents steps that were taken to minimize water usage, such as using forced-air cooling in place of cooling water when possible. In this primary design consideration, the water usage for this process was calculated at 1.9 gallons of water per gallon of ethanol.

Opportunities for Water SavingsGiven this information, it becomes clear that the energy and water demands of ethanol processes are closely integrated, and one way to reduce water demand is to reduce energy consumption. Many options are being pursued in this category. Producing broths with higher ethanol concentrations can reduce the energy needed for distillation. Alternative technologies to distillation, such as pervaporation (a membrane separation process), also have the potential to significantly reduce water usage.

A second option for reducing water demand is to utilize a different heat transfer medium, using forced-air fans for cooling instead of water where appropriate. This could potentially result in much lower evaporative and blowdown losses. In addition, new patented water

conservation technology has resulted in cooling towers with 20 percent reduction in water consumption (Owens, 2007) and new high efficiency dryer designs. Several of these options are currently being modeled at NREL to determine potential water, energy, and economic benefits for the cellulosic processes.

DOE is also in the process of examining water use issues associated with the growth of a biomass to fuels and chemicals industry in the United States. Specifically, water issues related to increased feedstock production (such as water availability and competing water use rights) needed to meet renewable fuel goals for the future will be studied. These must be quantified in terms of current and projected increases in feedstock production.

Contact Andy Aden at [email protected].

ReferencesAden, A., M. Ruth, K. Ibsen, J. Jechura, K. Neeves, J.

Sheehan, B. Wallace, L. Montague, A. Slayton, and J. Lukas, 2002. Lignocellulosic biomass to ethanol process design and economics utilizing co-current dilute acid prehydrolysis and enzymatic hydrolysis for corn stover, NREL/TP-510-32438, www1.eere.energy.gov/biomass/pdfs/32438.pdf.

Institute for Agriculture and Trade Policy (IATP), 2006. Water use by ethanol plants potential challenges, Minneapolis, MN. www.agobservatory.org/library.cfm?refid=89449

Owens, S., June 2007. Reduce cooling tower water consumption by 20%, Ethanol Producer Magazine, www.ethanolproducer.com

Phillips, S., A. Aden, J. Jechura, and D. Dayton, 2007. Thermochemical ethanol via indirect gasification and mixed alcohol synthesis of lignocellulosic biomass, NREL/TP-510-41168, www.nrel.gov/docs/fy07osti/41168.pdf.

Renewable Fuels Association, 2007. How ethanol is made, www.ethanolrfa.org/resource/made/

Summary of ethanol production process water demands. Corn ethanol values are from commerically operating plants; cellulosic values are model-based.

Fresh Water Demands Corn Ethanol: Dry Grind

Cellulosic Ethanol: Biochemical

Cellulosic Ethanol: Thermochemical

Cooling tower makeup (percent) 68 71 71

Boiler and process makeup (percent) 32 29 29

Overall water demand (Gal H2O / Gal EtOH) 3–4 6 1.9

The Numbers 96% of corn used for ethanol production is not irrigated

785 gallons water per gallon of ethanol (average crop irrigation)

3-4 gallons water per gallon ethanol (dry grind production)

1.9-6 gallons water per gallon ethanol (conceptual cellulosic production)

2-2.5 gallons water per gallon gasoline (petroleum refining)

0.6 gallons water per kilowatt-hour (coal-fired power plant)

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Water Use Efficiency: Saving More than Water

Jeannine Larabee and Hossein Ashktorab – Santa Clara Valley Water District

The Santa Clara Valley Water District (SCVWD) is the water wholesaler for Santa Clara

County, California. It serves 15 cities, of which San Jose is the largest, with 1.8 million residents and over 200,000 commuters. SCVWD meets the county’s water demands through a combination of local water (groundwater, surface water, recycled water, and water conservation) and imported water from the federal Central Valley Project and the State Water Project.

SCVWD places high priority on offering cost-effective, innovative water recycling and water conservation programs. Since these programs were initiated, water savings have been significant, but the benefits are far-reaching, and include substantial energy savings and reduced emissions of carbon dioxide and other air pollutants.

How Much Water is Saved?SCVWD’s water use efficiency programs, which include both water conservation and water recycling, reduce demands on existing water supplies and delay or eliminate the need for new water supplies for an expanding population. These effects are cumulative and increasing. Since the water conservation programs were implemented in FY 1992/93, a total of 300,000 acre-feet of water has been saved, with approximately 39,000 acre-feet saved in FY 2005/06 alone. Water recycling programs, implemented in FY 1998/99, have saved a cumulative 68,200 acre-feet, with 15,000 saved just in FY 2005/06. Combined, the SCVWD

water use efficiency program savings for FY 2005/06 met

around 15 percent of the total Santa Clara County water demand for that year.

The greatest water conservation savings are achieved through high-efficiency toilet and clothes washer rebate programs, low-flow showerhead distribution programs,

and pre-rinse sprayer distribution programs (for food services). SCVWD’s water conservation savings have increased each year due to expansion of and greater participation in these water conservation programs. Water recycling, or the use of treated wastewater for nonpotable applications, is used in a variety of ways, including for irrigation and industrial processes. SCVWD has established goals for water conservation to supply 92,000 acre-feet by the year 2020 and water recycling to supply 10 percent of total water use by the year 2020.

Besides the water supply management benefits of greater flexibility and increased reliability, the water use efficiency programs provide environmental benefits by helping protect the salt marsh habitat of South San Francisco Bay, local groundwater supplies, local

surface water supplies, and associated watersheds. These environmental benefits in turn provide significant aesthetic and human health benefits.

Indirect Benefits: Energy

and Air QualityWhile the primary goal of the District’s Water Use Efficiency programs is to use water more efficiently, ancillary benefits include energy savings and resultant air quality improvements. California’s water supply chain, or the route water follows as it is pumped and conveyed from its source, treated to drinking water standards, distributed, used, and treated to wastewater standards, is energy-intensive. Fifteen to 20 percent of all energy consumed in the state is water-related. The State Water Project alone, a 444-mile long aqueduct transporting San Francisco Bay-San Joaquin Delta water to Southern California, consumes two to three percent of all electricity in the state because of the high elevations and long distances over which water must be pumped and conveyed (Wolff and others, 2004). Thus, reducing flow through the water supply chain by using alternative water supply sources such as water conservation and water recycling decreases energy use.

Electricity production by power plants using nonrenewable energy sources such as natural gas and coal generates air pollutants, including reactive organic gases, particulates, nitrogen oxides, sulfur oxides, all of which have adverse human health or environmental impacts, and carbon dioxide, a greenhouse gas that contributes

SCVWD has saved approximately 1.42 billion kWh since the inception of its water conservation and water recycling programs


to global warming. Global warming and the climate changes that may result present many challenges for water agencies. For example, it is predicted that Northern California’s water supply system will be altered by changes in precipitation patterns and an earlier snowmelt. A reduction in water-related energy demand due to water conservation and water recycling reduces these air pollutants and allows the district to respond to the water supply challenges posed by global climate change.

Model Demonstrates SavingsPotential impacts of climate change on California’s water and energy resources have brought together professionals from both industries with the shared goal of understanding the connections between water and energy in the state water supply system. As part of this effort, models and methodologies to determine the energy embedded in California’s water supply system have been developed.

One such model, the spreadsheet-based “Water to Air Model,” was developed by The Pacific Institute (Wolff, 2004). The model’s whole-system approach for quantifying water-related energy use provides water supply planners with an overview of the energy intensity of different water supply options, allowing comparison of water supply scenarios. Users can input agency-specific water supply, energy use, and air emissions information, or use the default values. The model is user-friendly and customizable. SCVWD staff used this model to quantify the energy savings and air pollutant emission reductions garnered by the district’s water conservation and water recycling programs. Two scenarios were compared:

• Continued use of current water conservation and water recycling programs; and

• No use of conservation/recycling programs; with the water that has been saved instead supplied by imported water.

Model results showed that SCVWD has achieved significant energy savings and air emissions reductions since the inception of its water conservation and water recycling programs. For 1992/93 through 2005/06, the district saved approximately 1.42 billion kilowatt-hours of energy (see chart above), equivalent to the annual electricity required for 207,000 households based on average California household use (California Energy Commission, 2006) and representing a financial savings of approximately $183 million. These energy savings eliminated the emission of approximately 335 million kilograms of carbon dioxide, which (according to the U.S. EPA’s equivalency calculator) is the equivalent of removing 72,000 passenger cars from the roads for one year. Emissions of several other air pollutants were also reduced due to the energy savings from these programs, as indicated by figures for the period FY 1992/93 through FY 2005/06: reactive organic gases (20,900 kg), nitrogen oxides (146,200 kg), sulfur oxides (13,900 kg), and particulate matter smaller than 10 microns (25,700 kg).

Looking AheadWater conservation and water recycling programs clearly save energy and reduce air pollutant emissions. In the future, SCVWD will continue to offer its proven programs as well as develop new water use efficiency programs that have potential for both water and energy savings. The district also intends to continue to improve the energy efficiency of its operations, buildings, and practices

because of its strong commitment to the efficient use of water and energy.

At the state policy level, the SCVWD supports the integration of energy and water policies, such as the passage of AB 32, the Global Warming Solutions Act, which requires California to cut its greenhouse gas emissions by about 25 percent by 2020. The district also encourages increased financial support from energy utilities as well as state agencies for water-use efficiency, particularly cold water conservation, because of the significant benefits to be gained in energy savings, air quality, and mitigation of the effects of global climate change.

Contact Jeannine Larabee at [email protected].

ReferencesCalifornia Energy Commission, 2006, California

electricity consumption by sector, energy.ca.gov/electricity/consumption_by_ sector.html.

U.S. Environmental Protection Agency, Greenhouse Gas Equivalencies Calculator, www.usctcgateway.net/tool/

Wolff, G., 2004. Water to Air Models. Pacific Institute, www.pacinst.org/resources/water_to_air_models/

Wolff, G., R. Cohen, and B. Nelson, 2004. Energy Down the Drain, New York, Natural Resources Defense Council.

Fiscal Year

350

300

250

200

150

100

50

0

En

erg

y (

millio

n k

Wh

)

92-9

3

93-9

4

94-9

5

95-9

6

96-9

7

97-9

8

98-9

9

99-0

0

00-0

1

01-0

2

02-0

3

03-0

4

04-0

5

05-0

6

20-2

1

Total Energy Savings from

FY 92-93 through FY 05-06:

1.42 billion kWH

Energy savings from the SCVWD water use efficiency program (recycling and conservation).


The Southwest, including the U.S.-Mexico border region, is experiencing dramatic population

and economic growth, which in turn is driving steep increases in the demand for both water and energy. Population is increasing twice as fast on the border as at the national level in either country, and is projected to grow by 50 percent from 2005 to 2030. Much of this growth is occurring in 14 border sister cities.

Pumping Water Requires

Consuming EnergyIn the perpetually water-short Southwest, with its rugged terrain and high evapotranspiration rate, most options for increasing water availability require increased energy consumption. Depending on the type of contract and customer served, energy costs of pumping currently comprise a quarter to a half of the total rate charged for Central Arizona Project water (CAP, 2007/2008). Utilizing Arizona’s full Colorado River water allocation through CAP deliveries will cost tens of millions of dollars annually in energy. On a smaller scale, Sonora has its own interbasin water transfers, such as the Los Alisos/Rio Magdalena-Nogales aqueduct, that entail significant energy for pumping.

On both sides of the border, agricultural pumping represents a major energy demand. In the Mexican border states of Sonora and Chihuahua, groundwater pumping for irrigation accounts for 10 and 16 percent respectively of total state energy demand (Scott, 2007; CFE, 2006), although total agricultural power consumption began declining in 2000 in response to increasing power rates. The Comisión Federal de Electricidad (CFE) introduced reduced power rates for nighttime irrigation in 2003-04,

which initially led to an increase in total energy and groundwater consumption, likely due to lower costs and reduced controls on irrigation at night when labor costs are higher. However, one year after the nighttime irrigation rate

was introduced, total energy consumed and groundwater pumped for Mexican agriculture continued their decline.

Similarly on the Arizona side, irrigation represents 10 percent of electrical power sales revenue for the Sulphur Springs Valley Electric Cooperative, but electricity use by irrigation increased 45 percent from 2002 to 2005, largely due to customers switching to electricity as natural gas prices increased.

Energy for Water TreatmentWastewater treatment requires significant supplies of energy. On the U.S. side of the border, the Nogales International Wastewater Treatment Plant (NIWTP) treats about 15 million gallons per day (mgd) of wastewater originating from both Nogales, Arizona and Nogales, Sonora. Mexico has an allocation of 9.9 mgd per day at the plant, yet has regularly exceeded that amount over the last several years due to increased water supply and wastewater collection infrastructure in Nogales, Sonora. In 2004, the Maestros Group outlined a plan to build a 411-megawatt electrical generation plant in Nogales, Arizona, utilizing Mexican effluent for cooling. Despite its innovative

approach—the plant would have supplied electricity to both Arizona and Mexico—the plan has not moved forward.

Also in the works is Mexico’s plan to build a wastewater treatment plant in Los Alisos, about 10 miles south of Nogales, Sonora. The plant would treat wastewater in excess of the 9.9 mgd allocation at the NIWTP. Under the existing treaty with the United States, Mexico could retain and reuse scarce water on its side of the border; however, this would likely prove to be a costly choice in energy terms, as the wastewater would have to be pumped upgradient and over a watershed divide to reach the proposed new plant. Additionally, Mexico would lose the cost advantage of allowing wastewater to flow downgradient to the NIWTP and the economy-of-scale benefits the larger NIWTP offers.

As the foregoing discussion has shown, the demand for a range of water services in the border region has been accompanied by increased energy use. With energy costs rising, its sources politically unstable, and its supplies uncertain, this trend places water management at odds with the palpable need to limit energy consumption.

Add Climate Change to the MixAt the same time, the impacts of climate variability and change are becoming more widely accepted as important contributors to the water-energy link. In Mexico, the government and scientific establishment, sensitized by recent impacts of El Niño and La Niña, recognize the importance of climate on the agricultural and urban sectors. Mexico has taken a strong position on limiting global warming and is among those nations calling for such mitigative strategies as adoption of carbon caps and reduction of greenhouse gas emissions.

Mexico has taken a strong position on limiting global warming and is among those nations calling for mitigative strategies.

Linking Water and Energy Along the Arizona-Sonora Border Christopher A. Scott, Robert G. Varady, Anne Browning-Aiken, and Terry W. Sprouse – University of Arizona


The United States, as is well-known, has criticized and refused to sign the Kyoto Accords, while the Bush administration has until very recently questioned scientific research on global warming and denied human causation. However,

over the past several months, the U.S. public and its politicians are beginning to accept the need to address climate change. And in the border region, with its serious water and energy constraints, the issue has gained strong momentum.

In 2005, the states of Arizona and Sonora signed a “Declaration of Cooperation” to establish a joint binational climate change initiative (Arizona-Sonora Declaration, 2005), with follow-up activities planned by the Arizona-Mexico Commission.

see Arizona-Sonora, page 31

Lake Havasu City

Phoenix

CAP Canal

Tucson Nogales Arizona

Los Alisos/Rio

Magdalena-Nogales

aqueduct

Sonora

Santa Cruz River

Arroyo d

e los Alisos72 ft.

12,611 ft.

Los Alisos Basin

3,000 ft.

0 336 mi.distance

ele

va

tio

n

Colorado River Tucson

3200 kWh to pump one acre-foot of CAP water from the Colorado River to Tucson.

CAP Canal

Interbasin water transfers in Arizona and Nogales, Sonora require large amounts of energy. The profile of the Central Arizona Project through Arizona (right) shows an increase in elevation of 2900 feet from the Colorado River to its end near Tucson. The Los Alisos/Rio Magdalena-Nogales aqueduct in northern Sonora must cross over a watershed divide to reach Nogales.


Residential cooling and heating account for about 56 percent of the total energy consumed

in the typical U.S. home, according to the U.S. Dept. of Energy (DOE, 2005). In the Southwest, this energy is increasingly going toward air-conditioning rather than the traditional evaporative coolers, known as swamp coolers. The shift has implications for energy use, water use, and climate.

Energy UseStrictly in terms of energy use, the ongoing shift from swamp coolers to air conditioners could be considered unfortunate. Air conditioners generally use two to four times more electricity than swamp coolers. For a typical 2,000-square-foot Tucson residence, the electricity used by a swamp cooler can be as low as 250 kilowatt-hours in an average month, while an air conditioner consumes about 850 kilowatt-hours. In Tucson, this translates to a monthly electrical cost of $25 versus $85.

But a scarcity of water in the Southwest makes the comparison more complex, posing a challenge in determining the conservation strategy that can yield optimum savings for both energy and water. T. Lewis Thompson of the Environmental

Research Laboratory (ERL) at the University of Arizona found that during summer conditions in Tucson (May-September), a swamp cooler working at 75 percent efficiency uses an average of 150 gallons of water per day, while air-conditioning units do not directly use water. However, the generation of electricity requires water, a behind-the-scenes use that is easily overlooked.

Torcellini and others (2003) estimate that hydropower, which supplies about 12 percent of Arizona’s electricity, consumes about 65 gallons of water per kilowatt-hour generated because of high regional evaporation rates from reservoirs where it is generated (this value considers the total water evaporated from reservoirs serving Hoover and Glen Canyon dams versus the amount of electricity generated.) However, the coal-fired plants that supply most of Tucson’s electricity consume about half

Water-Energy Trade-Offs BetweenSwamp Coolers and Air ConditionersArunima Chatterjee and Melanie Lenart – University of Arizona

water distribution lines

air

air

evaporative pad

pump and screen

motor

blower

float

to house

Monthly energy and water consumption with resulting cost analysis for cooling a 2,000-square-foot Tucson residence using coal-powered energy and a rated 4,500-cubic-foot per minute evaporative cooler operating on low for May through September. For comparison, hydropower-based energy calculations are also shown, and indicate greater water use by an air conditioner than a swamp cooler. Thus, the source (or mix of sources) of energy is critical to this analysis.

Swamp coolers typically consist of a box with vented sides. A fan draws ambient air through vents and through pads that are kept moist by a water supply, pump, and distribution lines. The cooled, moist air is then delivered to the building via a vent in the roof or wall.

Coal-powered electricity HydropowerSwamp cooler

Air conditioner

Swamp cooler

Air conditioner

Electricity used (kWh/month) 250 850 250 850Water used directly by cooler (gals/month) 4,495 0 4,495 0Off-site water used to generate electricity (gals/month) 125 425 16,250 55,250Total water used (gals/month) 4,620 425 20,745 55,250Electricity cost (monthly, assuming $0.10/kWh) 25 85 25 85


a gallon of water for each kilowatt-hour of electricity produced. Applying this standard to the cooling of a 2,000 square-foot home, an ERL analysis found that monthly water consumption for an air-conditioning system is about 425 gallons, while an evaporative cooler requires about 4,620 gallons, including direct and indirect usage for both (see table below left). The source of energy is critical to this analysis, however. If the same calculations are made using hydropower, an air conditioner uses 55,250 gallons of water per month compared to an evaporative cooler’s use of 20,745 gallons per month.

Evaporative cooling works best in the dry months of summer. During the monsoon when outside air is already moist, the effectiveness of swamp coolers is limited. Air conditioning’s appeal is its ability to cool to a thermostatically controlled temperature regardless of the humidity. At some level, though, the cooling of a home usually equates to a warming of the planet, with air conditioners doing more damage than swamp coolers when the source of energy is one that produces greenhouse gases, such as coal.

Climate ConsiderationsThe collective choice of cooling equipment can affect the local climate as well. While air conditioners merely eject heat from the interior of a home or office into the outside air, swamp coolers can actually contribute to cooling the environment, indoor and outdoor. An evaporative cooler pulls air through moist pads, lowering the incoming air by as much as by 30 degrees (see figures, left and above right). Because those cooling their homes with swamp coolers must leave some windows open, some of this cooled air permeates outdoors.

A typical swamp cooler converts about 1 billion joules of energy a day from heat into other types of energy, including kinetic and latent energy. This amount of energy could warm a 6-foot-deep 12 x 12 foot pool by 20°F. Meanwhile, a typical air conditioner ejects about 63 million joules of energy per hour into the outside air, or a billion joules for every 16 hours of operation.

Arizona State University researchers were surprised to find daytime temperatures in parts of metropolitan Phoenix were no higher, and in some cases actually lower, than those in the surrounding desert despite the expected urban heat island effect. They surmised that their results reflected the evaporative cooling from pools, urban lakes, landscaped vegetation and perhaps even swamp coolers. ASU researcher Joseph Zender

noted that the ongoing shift from swamp cooling to air conditioning may eventually reduce some of that daytime cooling. Once the sun goes down, the desert cools down much quicker than the ciy with its heat-trapping pavement and vegetation. Some Phoenix-area urban temperatures averaged up to 20°F warmer than those in the nearby desert.

see Coolers, page 32

midnight 4 am 8am noon 4 pm 8 pm midnight

Wate

r E

vap

ora

ted

, g

al/

hr

20

15

10

5

0

Time

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100

90

80

70

60

50

40

Tem

pera

ture

, °F

Dry-bulb temperature

Wet-bulb temperature

Evaporatively cooled air

Water evaporated

Note: 4500 CFM BlowerOperated at Low Speed

Operating Period

Total water evaporated = 128 gal/daywith 15% blowdown

Total useage = 148 gal/day

Evaporative coolers work by converting some of the heat energy in air into latent heat and kinetic energy that is trapped in the process of evaporation of water. A modern swamp cooler with an 85 percent efficiency can cool 100°F daytime air down to about 68°F. In the process, it uses about 145 to 150 gallons of water a day, assuming it operates on low during the day and is turned off at night. (Figure and analysis courtesy T. Lewis Thompson of the University of Arizona Environmental Research Laboratory, data for Tucson, Arizona, June 2006.)


based bioenergy, we project California’s water withdrawals and consumption to decrease even further, up to 90 percent.

To make the collected data available in a more user-friendly manner, a Web-based tool was created to calculate the estimated water requirements (both withdrawn and consumed) of a given portfolio (see sidebar).

A Clear Benefit to Water Efficiency

in Energy PlanningThere are several key conclusions of this analysis. First, a water-efficient energy portfolio demands the right mix of primary energy sources, conversion technologies, and cooling technologies. Utilities should therefore focus on increasing investment in water-efficient electricity generation such as solar photovoltaics, wind power, and coal gasification systems.

Second, policies that encourage conservation of water can greatly reduce future water requirements. For example, issuing conservation credits to energy utilities that implement programs to reduce water use will help reduce both water and electricity consumption. Integration of water and energy infrastructure planning also offers several distinct benefits. Co-locating wastewater treatment facilities and power plants facilitates the increased use of reclaimed water in power plants, reducing potable water consumption and providing a reliable water supply.

Finally, many research gaps still exist. A thorough life-cycle assessment of electricity generation, including water use in facility construction, is needed to understand the full water requirements of electricity generation. Additionally, as water-efficient energy portfolios are developed, the feasibility must be determined, assessing both the availability of energy resources and patterns of demand.

Several issues must be considered in the integration of energy and water planning. First, relying on water-efficient renewable sources of energy decreases water use and may decrease greenhouse gas emissions and provide greater political security.

This transition to alternative sources of electricity must be accomplished, however, in a manner that will not compromise the reliability of our energy supplies. In addition to the impacts of electricity generation on water resources, we must consider other environmental impacts. For example, covering the deserts of California with solar panels may reduce pollution and conserve water, but may have significant impacts to regional biodiversity and ecosystems through habitat loss. Finally, impacts on water resources may be region-specific. As we see in the bioenergy sector, the production of dedicated energy crops may be limited in the arid Southwest, but may be more viable in wetter climates of the United States.

As freshwater resources will likely become more constrained in the future and may limit electricity generation, water efficiency must be considered in energy planning. This analysis provides a tool to support integrated planning between energy and water utilities, and to help government agencies integrate water considerations into planning for future energy supplies.

Contact: Dana Larson at [email protected]

ReferenceDennen, A., D. Larson, C. Lee, J. Lee, and S. Tellinghuisen, 2007. California’s Energy-Water Nexus: Water Use in Electricity Generation. Report to be published at University of California at Santa Barbara.

California’s Nexus, continued from page 21The Energy Intensity of Water Supplies

The total energy embedded in a unit of

water used in a particular place varies

with location, source, and use. The energy

intensity of water is the total amount of

energy, calculated on a whole-system

basis, required for the use of a given

amount of water in a specific location. All

steps in the process, starting with initial

extraction from a natural source through

conveyance, treatment, distribution, end-

uses, waste collection, treatment, and

discharge are included.

A spreadsheet-based computer model

(available from the author) calculates both

individual and cumulative energy inputs

of each process in the water system to

determine its energy intensity. The table

below illustrates the range of energy

intensities for various water systems in

Southern California.

The energy intensity calculator is available for no charge from the author. Contact R.C. Wilkinson at [email protected].

Energy intensity of selected water supply sources in Southern California.

kWh/acre-foot

RECYCLED WATER

GROUNDWATER

SURFACE WATER

SEA WATER

0 1000 2000 3000 4000 5000 6000

Efficiency

Reuse (IEUA)

Reuse (WBMWD)

Reuse (Osmosis)

Groundwater (WBMWD)

Groundwater (IEUA)

Groundwater (Ion Exchange)

Groundwater (RO)

CO River (MWD)

State Water Project (West Branch)

State Water Project (Coastal Branch)

State Water Project (East Branch)

State Water Project (Crafton Hill)

State Water Project (Cherry Valley)

Ocean Desal (West Basin)

Ocean Desal

IEUA — Inland Empire Utilities Agency; MWD — Metropolitan Water District;

RO — Reverse Osmosis; WBMWD — West Basin Municipal Water District

R. C. Wilkinson – University of California at Santa Barbara


Planning Together for the FutureIn the border region, U.S. and Mexican scientists and social scientists are meeting regularly and developing instruments to use jointly. One such effort would yield an ongoing, binational, U.S.-Mexico border climate diagnostic summary (Ray and others, 2007). This summary, to be prepared collaboratively and at regular intervals, would provide forecasts and value-added information on temperature, precipitation, and drought within the region. Once in place, the tool would help managers and policymakers in the water and energy sectors make more realistic and accurate decisions. And in a region of chronic multiyear drought, the importance of addressing societal and economic impacts of climate is essential to effective use of scarce water and energy resources.

Water and energy are closely coupled resources in the rapidly growing Arizona-Sonora border region. While there is increasing recognition of the water

resource implications of power generation, there is a concomitant need to more fully consider the energy implications of growing demands for water services.

Contact Christopher Scott at [email protected].

ReferencesArizona-Sonora Declaration, 2005. Declaration of

cooperation to establish the Arizona-Sonora Regional Climate Change Initiative, www.azclimagechange.gov/initiatives/

Central Arizona Project (CAP), 2007/2008. Final

2007/2008 rate schedule. www.cap-az.com/static/index.cfm?contentID=30.

Comisión Federal de Electricidad (CFE), 2006. Unpublished energy sales data.

Ray, A.J., G.M. Garfin, L. Brito Castillo, M. Cortez Vázquez, H.F. Diaz, J. Garatuza Payán, D. Gochis, R. Lobato Sánchez, R.G. Varady, and C. Watts. 2007. Monsoon region climate applications: Integrating climate science with regional planning and policy, Bull. Amer. Meteor. Soc., 88(6): 1-3.

Scott, C.A., 2007. Energy boom and groundwater bust: Mexico’s water-energy nexus with implications for the U.S. border region, presented at 1st Western Forum on Energy & Water Sustainability, Santa Barbara, CA, March 2007.

Arizona-Sonora, continued from page 27

Water Management Consultants is an international company providing specialized services in groundwater, surface water, geochemistry and engineering.

The company is expanding rapidly and has an interesting and challenging portfolio of projects in the US. Excellent experience and career development is offered to motivated individuals, together with competitive salary and benefits. Suitable candidates are sought for the following vacancies, based in our Tucson, Reno, and Denver Offices:

Senior HydrogeologistA minimum of 7 year experience with a Masters Degree in Hydrology or closely related discipline. Skills in numerical groundwater flow modeling would be a strong advantage.

Staff and Project HydrogeologistsGraduate through 4 years experience, with a Masters Degree in Hydrology or closely related discipline. Strong ability in numerical and analytical hydrogeology and a willingness to participate in field programs.

For further information or to arrange an interview please contact Piccola Dowling:Telephone: 520 319-0725Email: [email protected] N Business Center Drive, Suite 107Tucson, Arizona, 85705.

Hydrogeologists Needed


Alternative CoolingMany factors influence total water consumption in an evaporative cooling system, including residential design, location of the cooler, and the use of air modifiers such as vegetation and water.

The cooling efficiency of a swamp cooler can increase dramatically by “sensible” cooling of the air before it goes through the moist pads of the cooler. Sensible cooling can be achieved by strategic landscaping, rock beds, and water channels.

In a typical summer day in Tucson, air entering an evaporative cooler with 75 percent efficiency at a temperature of 100° F can exit with an air temperature of 75° F. Many newer evaporative cooling systems have an 85 percent efficiency.

For residences at the design stage, cool towers are another way to utilize the principle of downdraft evaporative cooling. Cool towers usually have a wet pad in the top of the tower. The cool air is heavier than warm air and sinks by means of gravity, creating its own airflow and eliminating the need for blowers or fans. The only power required is for a 12-volt pump to circulate water over the cooler pads. Generally, cool towers without fans are 20 to 30 feet tall and between 6 and 10 square feet. These systems require from 100 to 150 watts, and cool 1,000 to 2,500 square feet.

The need to consider energy as well as water demand for cooling options seems likely to increase in the coming years. The Intergovernmental Panel on Climate Change projects that summer temperatures in the Southwest will rise by at least several more degrees on average in decades to come, even more if society fails to stabilize greenhouse gas emissions. As temperatures rise, individuals will continue to seek a cool indoor refuge from outdoor heat. Meanwhile, society must look for ways to provide cooling in the most energy-efficient way possible, given other limitations.

T. Lewis Thompson of the ERL also contributed to the analysis. Contact Arunima Chatterjee at [email protected].

ReferencesArizona Climate Change Advisory Group, 2005.

Final Arizona Greenhouse Gas Inventory and Reference Case Projections 1990-2020. www.azclimatechange.us/documents.cfm

DOE, 2005. A consumer’s guide to energy efficiency and renewable energy. www.eere.energy.gov/consumer/your_home/space_heating_cooling/index.cfm/mytopic=12300

Southwest Energy Efficiency Project, 2004. New evaporative cooling systems: An emerging solution for homes in hot dry climates with modest cooling loads. www.swenergy.org/pubs/.

Torcellini, P., N. Long, and R. Judkoff, 2003. Consumptive water use for U.S. power production, National Renewable Energy Laboratory Publication NREL/CP-550-35190. www.nrel.gov/docs/fy04osti/35190.pdf

Coolers, continued from page 29

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R & DAg Pumping Causing Surface Sinking

The land surface in Central California dropped 30 feet in elevation from 1925 to 1977 and is still falling, reported the Fresno Bee. Worldwide, subsidence such as this resulting from extensive groundwater pumping, is “the largest human alteration of the Earth’s surface,” the USGS said, according to the Bee. As a result, in Central California, millions of dollars will be needed to repair damage to infrastructure such as irrigation canals and highways, and eventually the Mendota Dam on the San Joaquin River.

USGS scientist Kerry Arroues described for the Bee two kinds of subsidence affecting the California landscape. One is regional, in which deep groundwater pumping causes an overall lowering of the landscape; this is happening in the area near Mendota. Further south, the weight of irrigation water added to the surface has caused local, nonuniform subsidence, resulting in the transformation of once-smooth topography to rolling hills.

According to scientists, regional subsidence occurs in conjunction with droughts, the newspaper said. When snowpack is low and streamflow is reduced, farmers fall back on groundwater for irrigation, and subsidence increases. When river water is used, subsidence slows. Arroues estimated that an additional 10 feet of subsidence may have occurred in Fresno County’s west side since 1977.

Visit www.fresnobee.com.

Methane-Related Groundwater Pumping Raising Interest

The amount of groundwater pumped for the production of coalbed methane in Wyoming’s Powder River Basin is drawing attention. According to the Casper Star-Tribune, some groundwater wells have been pumping for two years or more while no gas is produced. The newspaper stated that according to the

Wyoming Oil and Gas Conservation Commission (WOGCC), “more than 14 percent of active coal-bed methane wells in the Powder River Basin in December were producing only water,” and “more than 39,000 acre-feet of water have been produced from wells that have not produced any gas.”

The pumped water is generally released to drainages or low-lying areas. Its quality is generally too poor, or the location too remote, for beneficial uses. Small amounts are used to supply stock wells or for irrigation.

In the interest of production efficiency and environmental concerns, some companies have begun to inventory the wells to determine where water savings might occur, said the Star-Tribune. Welldog Inc., a company in Laramie, Wyoming that specializes in “direct technical evaluation of coalbed natural gas reservoirs,” used data from WOGCC to analyze water production figures relative to gas production.

The analysis is not straightforward because some water pumping is necessary to reduce the regional hydrostatic pressure to allow gas production, even if a specific well is not producing gas. However, at a minimum, the newspaper reported, Welldog found that 8.6 percent of water-producing wells that have been in production for at least two years do not economically contribute to overall gas production; collectively they pumped about 29,000 acre-feet of water. The high end of the estimate is 39.3 percent.

According to the Star-Tribune, Welldog and other companies have begun to work with gas producers to improve production efficiencies and reduce the amount of water produced, a move supported by agricultural interests who only want as much water as they can use. Reducing the amount of water pumped would likewise reduce the energy demand for pumping, providing additional savings.

Visit www.casperstartribune.net and www.welldog.com.

Earth Fissure Maps Available for Arizona

In June, the Arizona Geological Survey (AZGS) released individual, 1:250,000 scale, earth-fissure planning maps of Cochise, Maricopa, Pima, and Pinal counties with an accompanying Open-File Report. The maps show all currently known earth fissures. This is the first step in preparing highly detailed fissure maps to be completed area by area over the next few years.

Earth fissures are associated with basin subsidence that accompanies extensive groundwater mining. In Arizona, fissures were first noted near Eloy in 1929. Their physical appearance varies greatly, but they can be more than a mile in length, up to 15 feet wide, and hundreds of feet deep.

During torrential rains they erode rapidly, presenting a substantial hazard to people and infrastructure. Moreover, fissures provide a ready conduit to deliver runoff and contaminated waters to basin aquifers. Rapid population growth in southern Arizona is increasingly juxtaposing population centers and fissures.

In response to the sudden reactivation in August 2005 of a 1.5-mile long fissure near Queen Creek, Arizona, the Arizona Legislature passed legislation to map earth fissures in Arizona. Effective Sept. 21, 2006, House Bill 2639 charged AZGS with 1) comprehensive mapping of earth fissures throughout Arizona, and 2) delivering detailed earth-fissure map data to the State Land Department for public access online. A complementary bill, A.R.S. 33-422, requires disclosure of earth fissures in nonincorporated areas.

The maps are available at www.azgs.az.gov/earth fissure planning maps.html or for $4 each at the AZGS bookstore in Tucson and the Department of Mines and Mineral Resources in Phoenix. The accompanying 25-page report, Earth Fissure Mapping Program: 2006 Progress Report; Open-file Report 07-01, will be available at the same locations and online.

continued next page


R & D (continued)

TAES gets TEEA from TCEQ

Scientists at the Texas Agricultural Experiment Station (TAES) El Paso Research Center earned the state’s highest environmental achievement: the Texas Environmental Excellence Award, presented by the Texas Commission on Environmental Quality. TAES earned the award for its achievements in water quality improvement for bacterial source tracking research.

TAES El Paso scientists carried out two large-scale projects to track pollution sources for two state agencies. Using state-of-the-art DNA fingerprinting and antibiotic resistance typing methods for E. coli, they identified specific animal and human sources of fecal pollution in seven different watersheds.

In addition, the researchers created a genetic library of E. coli bacteria isolated from known sources. The library could save millions of dollars on future fecal pollution source tracking projects. By pinpointing the sources of pollution, resource managers can develop effective pollution control strategies to ensure water is drinkable and safe for all users.

Visit elpaso.tamu.edu/Research/award.htm.

Report on Status of New Mexico Water Quality

A report issued last spring by the New Mexico Department of the Environment (NMED) summarizes the condition of the state’s water bodies and recommends federal measures to improve water quality management. The report was prepared to comply with U.S. EPA Clean Water Act requirements and was based on data collected from January 2002 through February 2004.

Surface water: Nearly 40 percent of New Mexico’s 6,500 miles of perennial streams do not meet standards for their designated use and 65 percent of lakes, reservoirs, and playas do not fully support

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designated uses. The major causes of surface water impairment are heavy metal contamination, sedimentation, temperature, and turbidity. Nonpoint source pollution is responsible for more than 95 percent of the impaired water quality of streams.

Groundwater: About 22 percent of facilities with groundwater discharge permits in New Mexico had confirmed groundwater contamination or presented a threat to groundwater as of early 2004. Groundwater contamination stems from both nonpoint sources (such as septic tanks, residual minerals from evapotranspiration, mining activities, and urban and agricultural runoff) and point sources (such as surface impoundments,

landfills, accidental spills and leaks, and injection wells). Naturally occurring radon and arsenic also affect water quality.

Recommendations: NMED’s recommendations to Congress and EPA reflect water quality issues common to many states in the Southwest. Among them:• Allow sufficient time for determining

the efficacy of nonpoint source pollution control programs before federal mandates are enacted, and make deadlines for compliance with mandates flexible to meet the conditions of the specific area.

• Rethink the required 40 percent nonfederal match for federal funding for water quality improvements. This

is a challenge for states with large land areas and small populations with low tax bases, as well as for tribes.

• Provide additional federal funding for water quality research, data collection (especially for the USGS), and wastewater treatment facilities.

• Make federal facilities operating within a state responsible for water quality protection, compliance, and remediation related to their activities.

• Develop federal programs and legislation to protect against groundwater contamination to support state programs and initiatives, rather than to supercede them.

continued next page

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• Use species appropriate for the ecosystem to evaluate impairment of a water body, and make standards flexible to take into account existing background conditions.

• Better integrate federal mandates to reflect close ties between water quality and water quantity issues.

The report is available at www.nmenv.state.nm.us/wqcc/303d-305b/2004/.

Portable Test Kits for Pathogen Detection

University of Arizona scientists are developing technology to rapidly detect and quantify specific pathogens in food and water in the field. Innovis Technologies, a business created by students in the McGuire Center for Entrepreneurship at the school’s Eller College of Management, has developed a portable test kit for use on solids (tissue) or liquids that can identify microbes at the genetic level in less than 10 minutes.

The test kit combines two key technologies. First, it uses biomolecules known as zinc fingers, which can be customized to recognize and bind to specific DNA sequences, such as from E.coli. Highly specific zinc fingers now can be developed within weeks, thanks to new computer modeling software.

Second, Innovis’ proprietary detection system was developed to produce an easily observed color change if DNA from the microbe of interest is detected. No color change means no target pathogen.

Innovis is promoting the test kits for use with irrigation water, well water, fresh produce, and meat products. According to the company, the technology “can potentially be adapted to any DNA sequence, generating nearly unlimited adaptability both for microbial identification as well as human, plant, and animal genetic characterization.”

According to an April 19 article in the Tucson Citizen, the test kits will have to comply with U.S. EPA testing requirements before they can be marketed. The students are meeting with potential investors, and plan to sell the kits for $35.

Visit www.innovistechnologies.com and www.tucsoncitizen.com.

Grant Will Advance One-Stop Water Data Website

David Maidment, director of the University of Texas at Austin’s Center for Research in Water Resources, recently received a five-year, $4.6 million grant from the National Science Foundation (NSF) to create a one-stop website where

water-related data from hundreds of federal, state, and local agencies will be available. Early aspects of this Hydrologic Information System were described by Maidment and his colleagues in Southwest Hydrology (May/June 2006). Maidment received the grant as part of the Consortium of Universities for the Advancement of Hydrologic Science Inc. He is cooperating with researchers from Drexel University, Ohio State University, and the San Diego Supercomputer Center.

Ready access to comprehensive water information will help municipalities make more informed responses to water challenges, such as the droughts occurring in much of the Southwest. Currently, water managers obtain streamflow measurements, soil data, and satellite and meteorological data from dozens of organizations, each of which gathers data for different purposes and often stores them using different software.

Besides providing nationwide water data at one site, Maidment and colleagues plan to provide user-friendly programs on the website for modeling how a given water resource could change over time. Eventually, they hope to make the system easy enough for the general public to use.

Visit www.engr.utexas.edu/news/articles/200703061176/ and www.cuahsi.org/his.html.

R & D (continued)


International Recharge Experts Convening in the Southwest

An excellent opportunity to learn from recharge experts from around the world is coming soon to the Southwest. The 6th International Symposium for Managed Aquifer Recharge (ISMAR6) will be held Oct. 28-Nov.2 in Phoenix.

In addition to three days of technical talks, the meeting will offer four workshops and a day of field trips. Presentations will be made by authors from 17 different countries and 14 U.S. states covering a wide range of topics, including the practical aspects of recharge in such diverse places as Europe, the Middle East, Africa, India, Australia, Mexico, Japan, and Taiwan.

Visit www.ismar2007.org for more information.

ASCE Presents Infrastructure Action Plan to Congress

The American Society of Civil Engineers’ (ASCE) most recent Report Card for America’s Infrastructure (2005; also see Southwest Hydrology, Mar/Apr 2006) gave the nation’s critical infrastructure an overall grade of D. In March, ASCE members from across the country delivered an Infrastructure Action Plan to their respective representatives from the 110th Congress as part of the organization’s annual Legislative Fly-In Program. The plan calls for 11 specific actions, seven of which concern water-related issues:

• Enact the National Infrastructure Improvement Act to establish the National Commission on Infrastructure of the United States;

• Enact the Dam Rehabilitation and Repair Act (H.R. 1098) to address the most critical non-federal public dams;

• Enact a national levee safety program, including a nationwide inventory of levees and mandatory inspection requirements;

• Enact the Water Quality Financing Act of 2007 (H.R. 720) to provide vitally

needed federal aid through the State Revolving Loan Fund (CWSRF) program;

• Authorize $1 billion in annual funding for the Safe Drinking Water Act State Revolving Loan Fund (DWSRF);

• Enact a Water Resources Development Act (WRDA) that requires a more comprehensive approach to water resources projects constructed by the U.S. Army Corps of Engineers; and

• Ensure the integrity of the Inland Waterways Trust Fund.

ASCE estimates that the United States needs to invest $1.6 trillion in federal, state, and local funds over a five-year period to bring the nation’s infrastructure to a condition that meets the needs of our current population.

Much of the needed funding is already allocated in existing budgets—only about one-third of the total investment needed will be new funding. However, the $1.6 trillion does not account for future population growth.

ASCE’s Report Card for America’s Infrastructure and the Infrastructure Action Plan are at www.infrastructurereportcard.org.

New Journal for Water Practitioners

Last spring, the Water Environment Foundation (WEF) released the inaugural issue of Water Practice, a new peer-reviewed online journal for water practitioners. The first issue featured topics related to residuals and biosolids. Full access to the journal is available at no cost through December 2007.

Water Practice features articles on monitoring, facility operations and maintenance, management, and policy. Each issue focuses on a specific water quality topic, often coinciding with recent WEF specialty conferences. Upcoming issues will focus on topics such as odor control, disinfection, nutrient removal, collection systems and compounds of emerging concern.

Visit www.wef.org/ScienceTechnologyResources/Publications/WaterPractice/.

Rio Grande One of Top 10 Rivers at Risk Worldwide

The Rio Grande is among the world’s top ten rivers at risk, according to a

SOCIETY PAGES


report released in March by the World Wildlife Fund. The WWF report names the world’s rivers that are facing widespread degradation while millions of people depend on them for survival. The Rio Grande along the U.S.-Mexico border made the list because it is severely threatened by water diversions, widespread alteration of the floodplain, dams, and pollution. It was the only North American river on the list.

The Rio Grande and its tributaries run through the arid Chihuahuan Desert, and the area is home to a rich diversity of freshwater species. The river is also the lifeblood of the region’s economy, providing water to some of the fastest-growing urban areas in the country and thousands of farms and ranches. Irrigation accounts for more than 80 percent of all water diversions from the river.

In response, WWF is working to improve irrigation in the Rio Grande valley so

that water can remain in the river for the benefit of fish and other wildlife, and so farmers and ranchers can secure a reliable supply of water. WWF also seeks to establish more parks and protected areas along the stretches of the river that are most important for wildlife.

The report, The World’s Top Ten Rivers at Risk, is available at www.worldwildlife.org/news/pubs/10rivers.pdf.

American Rivers’ Top 10 Rivers at Risk

In April, American Rivers announced the 10 most endangered rivers in the United States, a list that includes three in the Southwest. Topping the list was the Santa Fe River in New Mexico, followed by San Mateo Creek in California. Texas’s Neches River came in at number six.

The Santa Fe was deemed most at risk because for most of the year it lacks any water at all—the biggest risk any river could face, according to American Rivers. The San Mateo Creek in Orange County suffers from plans to bury it to accommodate a new transportation corridor. The Neches is one of the last wild rivers in Texas and home to the state’s newest wildlife refuge, but lawmakers are proposing to build a dam on it.

The annual American Rivers list is compiled from nominations from river groups, environmental organizations, local governments, and taxpayer watchdogs. It aims to highlight rivers facing the most uncertain futures rather than those with the worst chronic problems. The Rio Grande (see previous article) was not on the list.

Visit www.americanrivers.org.

New Director for ACWA

The Board of Directors of the Association of California Water Agencies (ACWA) appointed Timothy Quinn as executive director for the 460-member statewide association effective July 2. Quinn served with the Metropolitan Water District

of Southern California for 22 years as the district’s primary representative for statewide issues. During that time, he helped to create the Drought Water Bank, and worked to negotiate the 1994 Bay-Delta Accord and the Monterey Agreement. Before joining Metropolitan, Quinn was a project manager at the Rand Corporation, specializing in research on natural resource and environmental policy issues.

Steve Hall, ACWA’s previous executive director, will retire at the end of the year after leading the organization for 15 years.

ACWA is a statewide association of public agencies whose 460 members are responsible for about 90 percent of the water delivered in California.

Visit www.acwa.com.

WateReuse Maintains Facilities Database

Agencies, utilities, consultants, and reuse water customers seeking information on the practice and implementation of water reuse can find answers at the WateReuse Association’s National Database of Water Reuse Facilities (NDWRF). It is a comprehensive database of reuse programs and facilities across the United States.

Information available from the database includes reclaimed water production capacity and extent of reclaimed water distribution systems; reclaimed water users in the United States, including the quantity of reuse for such applications as irrigation, industrial, and recharge; utility program management practices; production and distribution data; reclaimed water rates; and utility contracts that may have additional information on reuse programs.

Information does come at a price. WateReuse Association members and WateReuse Foundation subscribers receive limited complimentary access to data, but queries from nonmembers and extensive searches from members are subject to a fee based on the query.

To access the database, visit www.watereuse.org/ndwrf/.

SOCIETY PAGES (continued)


Sustainable Water Management: Guidelines for Meeting the Needs of People and Nature in the Arid West

Betsy Woodhouse – Southwest Hydrology

The issues surrounding water management are technically and legally complicated, presenting challenges to developing sound public policies. A new report from the Tucson-based Sonoran Institute, Sustainable Water Management: Guidelines for Meeting the Needs of People and Nature in the Arid West, explores the groundwater-surface water relationship and proposes a framework for sustainable water management. The report looks at these issues as applied to three Arizona river basins—the San Pedro, Santa Cruz, and Verde—and recommends water management policies that could allow the state to prosper while protecting its important river systems.

The report’s suggested approach to sustainable water resources management has three primary objectives:

• provide for the needs of current and future residents of the area and those of downstream users, human and nonhuman;

• protect aquifer-stream system conditions sufficient to maintain acceptable baseflow and associated aquatic, wetland, and riparian habitats;

• protect restorative flood flows to maintain the stream channel and the aquatic, wetland, and riparian habitat conditions necessary for plants and animals to reproduce and grow.

Recommendations for attaining these objectives in Arizona include:

• resolve uncertainty over surface water rights (i.e., adjudicate);

• create new water-management authorities that can define water available for allocation, allocate water resources among new and existing users, and pursue supply augmentation strategies;

• pursue recharge and re-use projects to encourage more effective use of

existing water resources, including municipal effluent;

• improve international and regional cooperation.

At 52 pages with plenty of photographs and maps, the report is attractive, easy to read, and includes informative assessments of the state of the three river basins. But the sustainability guidelines are fairly general.

The Sonoran Institute had the report reviewed by 34 stakeholders from the three basins, including developers, farmers, ranchers, politicians, environmentalists, and engaged citizens. Their comments, summarized on the website, are applicable to any attempts to develop water management guidelines.

Reviewers strongly supported the broad concepts presented in the report, but said it is somewhat idealistic and general, and would be more useful if it better acknowledged existing social, economic, political, and legal frameworks within which water managers must operate. In addition, implementation details need to be worked out. Reviewers disagreed about whether local control is preferable, but agreed that a “one-size-fits-all” plan may not be appropriate.The report was viewed as having an environmentalist agenda, which some thought an advantage and some a disadvantage. Finally, reviewers unanimously cited the need to inform the public and policymakers about the value of the proposed approach.

To view the 52-page report, executive summary of in-depth stakeholder interviews, and list of interview participants, visit www.sonoran.org.

IN PRINT

Ground-water flow model of the Sierra Vista subwatershed and Sonoran portions of the Upper San Pedro Basin, southeastern Arizona, United States, and northern Sonora, Mexico, by D.R. Pooland J.E. Dickinson.

http://pubs.usgs.gov/sir/2006/5228/

Flow velocity and sediment data collected during 1990 and 1991 at National Canyon, Colorado River, Arizona, by N.J. Hornewer and S.M. Wiele.

http://pubs.usgs.gov/ds/2007/246/

Simulation of multiscale ground-water flow in part of the northeastern San Joaquin Valley, California, by S.P. Phillips, C.T. Green, K.R. Burow, J.L. Shelton, and D.L. Rewis.


Analysis of the magnitude and frequency of peak discharges for the Navajo Nation in Arizona, Utah, Colorado, and New Mexico, by S.D. Waltemeyer.



Volunteer Network Spawns RainMapper Service

Data from backyard rain gauges are supporting research, drought monitoring, weather reporting, and a new Web service that provides neighborhood-specific rainfall reports to homeowners without rain gauges. RainLog.org is a Web-based network of more than 1,100 volunteer weather watchers that measure and report rainfall in their backyards.

As the Southwest enters a tenth year of drought, many homeowners are more carefully irrigating their landscapes and adjusting for weather conditions. But the intense, localized nature of monsoon precipitation makes it difficult to determine how much rain fell in a specific

neighborhood. Official rainfall amounts are usually measured at an airport or some other public site far from residential neighborhoods, making it difficult to adjust an individual irrigation schedule

to the local conditions.

RainMapper is a free service based on RainLog.org, developed at the University of Arizona with support from a U.S. Bureau of Reclamation conservation grant. Homeowners who register for the free RainMapper service

through the RainLog.org website receive e-mails with information on how much rain fell in their neighborhood each time it rains within five miles.

Soon, RainMapper also will provide interpolated rainfall estimates based on research by Garcia and others (in

review). These interpolations will improve upon the current practice of estimating rainfall at an ungauged location using an inverse distance squared function by using more advanced approaches to weight readings from nearby gauges. The advanced method improves accuracy particularly for convective storms such as the Southwest’s summer monsoons.

These findings emphasize the need for a dense network of gauges to capture the spatial variability of monsoon storms. Therefore, RainMapper results will be most reliable in areas with many active RainLoggers. Currently, the metropolitan Tucson area has over 450 RainLoggers and Maricopa County has over 300.

For more information, or to subscribe to RainLog or RainMapper, visit www.rainlog.org.

ReferenceGarcia, M., C.D. Peters-Lidard, and D.C. Goodrich,

Spatial interpolation of precipitation in a dense gauge network for monsoon storm events in the southwestern U.S., Water Resour. Res. (in review).

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Super Slug

Hyeyoung Sophia Seo – Colorado School of Mines. Software Review courtesy of International Ground Water Modeling Center and Colorado School of Mines

Super Slug is a commercial Windows-based program that calculates aquifer transmissivity and hydraulic conductivity from slug test data. The program uses the four most popular slug-test data analysis methods: 1) Cooper, Bredehoeft, Papadopulos; 2) Bouwer and Rice; 3) Hvorslev; and 4) Ferris and Knowles. Super Slug handles both falling and rising head tests, and the required input is simple compared to other aquifer test programs.

Data entry is easy; data can be entered or modified at any time. Super Slug can read time and drawdown values directly from digital data logger files in most cases without editing, and can import an AQTESOLV file in DOS format. In Super Slug, the term “drawdown” does not refer to a change in hydraulic head,

but to actual water-level measurements made during the test. It would be clearer if the term “drawdown” was changed to “heads” or “measurements.”

One of the best features of Super Slug is its flexibility for fitting the model to the data. Users can evaluate which solution better fits their field data simply by switching to each option. When graphical methods are used, the user can easily exclude unwanted points at the beginning and end of the test to obtain a better fit. Super Slug also has a convenient drag-and-drop feature for matching a type curve to data for the Cooper method. When the automatic option is used, Super Slug calculates aquifer parameters without user interaction and results are displayed on the screen in a report format.

Using a simple data set, easy-to-use Super Slug produced similar values of hydraulic conductivity as the more sophisticated

program, AQTESOLV, 8.71x10-3 m/d compared to AQTESOLV’s 8.21x10-3 m/d.

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Bouwer and Rice Graph

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T H E C A L E N D A R

SEPTEMBER 2007

OCTOBER 2007

September 10-11 CLE International. Texas Water Law (conference). Austin, TX. www.cle.com/upcoming/PDFs/AUSWAT07.pdf

September 10-13 National Ground Water Association. Monitored Natural Attenuation: Mechanisms, Site Characterization, Evaluation, and Monitoring (Sept. 10-11) and Advanced Techniques for Evaluating and Quantifying Natural Attenuation (Sept. 12-13) (short

courses). Las Vegas, NV. info.ngwa.org/servicecenter/Meetings/

September 17-18 CLE International. Western Water Law Superconference. Las Vegas, NV. www.cle.com/

September 17-18 Midwest Geosciences Group. Improving Your Personal and Project Management Skills. Naperville, IL.

www.midwestgeo.com/projmgmt2007.htm

September 18-19 Groundwater Resources Association of California. 16th Annual/26th Biennial GRA Conference and Meeting. Sacramento, CA. www.grac.org

September 20-21 Univ. of AZ programs, COMET, NWS, and Vaisala. 4th Symposium on Southwest Hydrometeorology. Tucson, AZ.

www.atmo.arizona.edu/swhs/

September 24-27 National Ground Water Association. Groundwater Geochemistry: Fundamentals (Sept. 24-25) and Applications (Sept. 26-27) (short

courses). Park City, UT. info.ngwa.org/servicecenter/Meetings/

September 24-29 Association of Engineering Geologists. AEG’s 50th Annual Meeting. Los Angeles, CA. www.aegsc.org/2007-Meeting/

September 28-October 1 National Ground Water Association. 2007 Theis Conference - Conjunctive Management of Ground Water and Surface Water:

Application of Science to Policy. Park City, UT. info.ngwa.org/servicecenter/Meetings/

September 30-October 5 U.S. Committee on Irrigation and Drainage. USCID 4th International Conference on Irrigation and Drainage. Sacramento, CA.

www.uscid.org/07call.PDF

October 1- 2 CLE International. Utah Water Law Superconference. Salt Lake City, UT. www.cle.com/

October 1- 3 National Ground Water Association. Borehole Geophysical Logging for Water Recovery/Water Supply Applications (short course).

Garden Grove, CA. www.ngwa.org

October 1- 3 National Ground Water Association. An Introduction to Ground Water (short course). Park City, UT. info.ngwa.org/servicecenter/Meetings/

October 2- 4 U.S. EPA and Arizona Dept. of Environmental Quality. Desert Remedial Action Technologies Workshop. Phoenix, AZ. www.clu-in.org/

techdrct/techpubs.asp

October 13-17 WEFTEC. 80th Annual Technical Exhibition and Conference. San Diego, CA. www.weftec.org/Education/CallforAbstracts/

October 22-23 National Ground Water Association. 6th International Conference on Pharmaceuticals and Endocrine Disrupting Chemicals in

Water. Costa Mesa, CA. info.ngwa.org/servicecenter/Meetings/

October 23-24 Midwest Geosciences Group. Aquifer Testing for Improved Hydrogeologic Site Characterization. Fort Collins, CO.

www.midwestgeo.com/

October 28-31 Geological Society of America. GSA Annual Meeting and Exposition. Denver, CO. www.geosociety.org/meetings/2007/

October 28-November 2 AHS, IAH, ASCE/EWRI, UNESCO. ISMAR6: The 6th International Symposium on Managed Aquifer Recharge. Phoenix, AZ.

www.ismar2007.org

November 1- 2 CLE International. California Water Law. Pasadena, CA. www.cle.com/

November 5- 6 National Ground Water Association. Petroleum Hydrocarbons and Organic Chemicals in Ground Water: Prevention, Detection, and

Remediation Conference. Houston, TX. info.ngwa.org/servicecenter/Meetings/Index.cfm#MT1

November 5- 6 Nevada Water Resources Association. Climate Change Symposium. Las Vegas, NV. www.nvwra.org/events.asp

November 7- 9 Central Coast Agricultural Water Quality Coalition. 2007 National Conference on Agriculture and the Environment. Monterey, CA.

www.agwaterquality.org/2007conference/

November 8-10 California Groundwater Association. 59th Annual CGA Convention and Trade Show. Reno, NV. www.groundh2o.org/events/events.html

November 12-15 American Water Resources Association. 2007 Annual Conference: Hazards in Water Resources. Albuquerque, NM.

www.awra.org/meetings/New_Mexico2007/index.html

November 14-15 Groundwater Resources Association of California. DNAPL Source Zone Characterization and Removal. Long Beach, CA.

www.grac.org/dnapl.asp

November 15-17 International Center for Arid and Semiarid Land Studies. Water in Arid and Semiarid Lands: Innovative Approaches and Informed

Decision-Making. Lubbock, TX. www.iaff.ttu.edu/home/icasals/conference/

NOVEMBER 2007


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