inconvenient hydrology?

Southwest HydrologyUniversity of Arizona - SAHRA

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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

Inconvenient Hydrology?

Volume 6/Number 1 January/February 2007

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Climate change is a hot issue these days. What is certain is that temperatures are increasing along with atmospheric carbon dioxide concentrations; changes in precipitation are less certain. In this issue we consider the impacts these changes might have on water resources in our region. The short answer? Warmer temperatures mean that less precipitation falls as snow and evapotransporation rates increase. The clearest implication for water managers is that variability of water supplies will increase, and storage issues will become critical. This issue’s feature articles outline both the likelihood and uncertainty of where we may be headed.

Make plans to attend Southwest Hydrology’s upcoming symposium (sponsored jointly with the Arizona Hydrological Society) on “Sustainable Water, Unlimited Growth, and Quality of Life: Can We Have It All?” Among the specific issues we’ll address is whether current policy reflects water supply reality in the Southwest. Groups across the region are struggling with these and similar issues, and the conference is designed to compare and contrast various local, state, and regional perspectives. The symposium is Aug. 29-Sept. 1, 2007 in Tucson. We are now soliciting abstracts, sponsors, and exhibitors: see page 5 and visit the symposium website at www.watersymposium.org.

Thanks to all the contributors to this issue, as well as to our sponsors—both groups are essential to our continued success.

Betsy Woodhouse, Publisher

A bimonthly trade magazine for hydrologists, water managers, and other professionals working with water issues.

Southwest Hydrology

University of Arizona - SAHRA

P.O. Box 210158-B

Tucson, AZ85721-0158

Address Service Requested

A publication of SAHRA, an NSF Science and Technology Center


InconvenientHydrology?

Volume 6/Number 1January/February 2007

Southwest HydrologyPublisher

Betsy Woodhouse

Technical Editor Howard Grahn

Editor Mary Black

Art Director Kyle Carpenter

Graphic Designer Mike Buffington

Software Review Coordinator Eileen Poeter

SAHRA Knowledge Transfer Gary Woodard

Contributors

Advisory Board David Bolin, R.G. Charles Graf, R.G. John Hoffmann Jeff Johnson

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

Stan Leake Ari Michelsen, Ph.D.

Peggy Roefer Nabil Shafike, Ph.D.

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

Printed in the USA by Arizona Lithographers

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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each announcement is free; after that, the charge is $70 per additional 70 words. To place an ad, contact us as shown

below. All announcements, of any length, may be posted on our website for no charge (www.swhydro.arizona.edu).

Editorial Contribution Southwest Hydrology welcomes letters and contributions

of news, project summaries, product announcements, and items for The Calendar. Send submissions by mail or email as

shown below. Visit www.swhydro.arizona.edu for additional guidelines for submissions.

Web Sites Southwest Hydrology - www.swhydro.arizona.edu

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CONTACT US Southwest Hydrology, The University of Arizona, SAHRA

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

Kyle W. Blasch Jeannie R. Bryson

Jon Eischeid Gregg Garfin

Kathleen C. Hallett Jim Henderson Martin Hoerling

John P. Hoffmann Travis E. Huxman

Jeanine Jones Melanie Lenart Sue McClurg

John E. McCray Michael L. Meyer

Russell L. Scott S. Amina Sena David Shaull Joel B. Smith

Kenneth M. Strzepek

From thePublisher


1955 to 2005 annual mean surface temperature change, based on surface air measurements at meteorological stations and ship and satellite measurements for sea surface. Image modified by Mike Buffington from 2-D projection published by J. Hansen, R. Ruedy, M. Sato, and K. Lo, 2006, NASA Goddard Institute for Space Studies, available at data.giss.nasa.gov/gistemp/2005/.

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� • January/February 2007 • Southwest Hydrology


A bimonthly trade magazine for hydrologists, water managers, and other professionals working with water issues

We thank the following sponsors for their support:

P.O. Box 210158B, Tucson, AZ 85721-0158 · visit our web site: www.swhydro.arizona.edu · 520.626.1805

January/February 2007 • Southwest Hydrology • �

Publishing Southwest Hydrology furthers SAHRA’s mission of promoting sustainable management of water resources in semi-arid regions.

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 Climate Change Effects on Southwest Water ResourcesGregg Garfin and Melanie LenartHow much do we really know about the impacts of climate change on water resources in the Southwest? What do historical and paleoclimate observations tell us? What are the strengths and weaknesses of climate model predictions? And what human factors bear on the equation?

18 Past Peak Water in the SouthwestMartin Hoerling and Jon EischeidForty-two climate simulations were run on 18 different coupled ocean-atmosphere-land models to determine probable consequences of future climate change on Lees Ferry streamflow. It ain’t pretty.

20 Emerging State Policies on Climate ChangeJeanine JonesStates are increasingly setting their own climate change policies, mostly focused on two fronts: reducing greenhouse gas emissions and increasing adaptability to climatic extremes. California and Oregon are among the leaders.

22 Climate Change Through the Eyes of Water ManagersBetsy WoodhouseWater managers throughout the Southwest share their strategies for addressing the impacts climate change may have on their systems. They offer a wish list of climate information that would help them better face the future.

24 Expanding the Tool Kit for Water Management in an Uncertain ClimateJoel B. Smith, Kathleen C. Hallett, Jim Henderson, and Kenneth M. StrzepekPaleodata from tree rings provide valuable information to water managers about past climate variations, while climate models offer predictions about the future. Combining the two types of information poses a challenge, but scientists in Boulder, Colorado, are finding the effort worthwhile.

26 Spring Arriving Earlier in Western StreamsWhat do we know for certain about recent trends toward diminished snowpack and earlier snowmelt and their causes? This article summarizes research published on the topic by the USGS, Watershed Management Council, and other scientists.

28 Climate Change, Vegetation Dynamics, and the Landscape Water BalanceTravis E. Huxman and Russell L. ScottIncreased carbon dioxide in the atmosphere will have an effect on plants and ecosystems. Changes in the composition of plant communities at the landscape scale will in turn be reflected in the regional water balance. What can we expect to see?

Departments8 On the Ground

Measuring discharge by dye tracerLocal meteoric water line helps determine Verde recharge areas

12 GovernmentEPA pesticide approval ruling EPA lowers drinking water goals Laboratory integrity findings disputedReclamation’s 2007 planSan Joaquin River restorationSNWA water transfer updateWalker Lake discussions stallSan Juan-Chama contracts signed

13 Hydrofacts

31 R&DNew model water compactBeetles curb TX saltcedarLong Beach desal patent pendingNEMI database expanded

33 PeopleTamminen resignsIn memory of Stuart Pyle In memory of Michael BrophyMyers new USGS leaderMcConnell wins research award

34 Business Directory

38 Company LineAZ water auction attemptedTestAmerica acquires STL

39 EducationWEF’s Water Leaders class

40 Movie ReviewAn Inconvenient Truth

41 Software ReviewHYDRUS, reviewed by John E. McCray

42 The Calendar

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Inconvenient Hydrology?How will climate change impact water resources? That’s the million-dollar question for water managers in the Southwest. As with any prediction about the future, we depend on past and present data, our understanding about how systems work, and models to forecast the range of likely future conditions. Measured and tree-ring-reconstructed streamflow data and ice cores tell us about climate-induced changes in the timing of runoff and the range of climate variability over centuries. Ecosystem investigations help us understand how plants respond to changes in atmospheric carbon dioxide and how such changes might affect land-use cover and, in turn, the hydrologic system. As for the models: what are they telling us, and how much confidence can we place in them? Can or should water managers respond to their predictions? Read on…


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ON THE GROUNDMeasuring Ephemeral Discharge by Dye Tracer Michael L. Meyer and S. Amina Sena – New Mexico Highlands University, and David Shaull – Los Alamos National Laboratories

Streamflow measurements in arroyos of the arid Southwest are complicated by the ephemeral nature of runoff events, complex cross-sectional channel geometry, and steep slopes. The short duration of runoff events makes manual, on-site discharge measurements difficult or impossible to use for developing stage-discharge relationships. Manning’s empirical equation for uniform, open-channel flow or other mathematical modeling methods are generally employed in the absence of other alternatives. The purpose of this project was to develop stage-discharge rating curves at selected Los Alamos National Laboratory (LANL) stream monitoring sites using a dye tracer.

Rhodamine WT dye was purchased as a 20 percent solution and diluted to 0.5 percent and 1.0 percent for injection purposes. Four arroyo sites were equipped with event-activated dye injection equipment and automated water samplers. Dye injection equipment was located 50 to 200 feet upstream of the point of collection to ensure homogenous mixing of the dye with stream water. A datalogger system at the downstream point of collection was equipped with an ISCO water

contact sensor, stream stage recorder, and ISCO sampler (see photos). The sampler contained 24 one-liter bottles and was programmed to collect 250 milliliters (mL) of water every 10 minutes when the water sensor was submerged by event runoff. Dye injection was initiated at a predetermined stage threshold during each runoff event. The dye pump was calibrated to deliver dye at a rate of 40 mL per minute.

Varying dye concentrations were analyzed with a fluorescence spectrophotometer and converted to discharge in cubic feet per second (cfs). Stage was regressed against discharge to develop a rating curve.

Dye injection and sampling were successfully activated Aug. 24, 2005 during a runoff event in Acid Canyon. Stage values recorded from 12:00 to 18:00 varied from 1.0 foot (no flow) to a peak of 3.1 feet at 13:35 (see chart, below left). The signal from the water sensor, recorded every five minutes, indicated continuous contact with water from 13:35 to 15:00. Continuous dye

dripping occurred during the same period. The ISCO sampler collected samples at 10-minute intervals starting around 13:00. Dye concentrations were quantifiable for flow calculations from seven bottles collected between 13:55 and 15:05. Dye concentrations were used to calculate discharge (Q, in cfs) and to develop a rating curve with stage versus discharge:

Stage = 0.3596 lnQ + 1.2; R2 = 0.96.

Seven discharge and stage values and one additional point representing 0.0 cfs with a stage of 1.0 feet were included in

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Event hydrograph (predicted Q) determined from stage-discharge rating curve, discharge determined from stream dye concentration, stream dye concentration, water sensor voltage, and stream stage.

Total suspended solids (TSS) concentration, TSS load, and event hydrograph (predicted Q).

Dye and pump (top) and actuator to release dye into the stream.

Acid Canyon Event 8/24/05


the regression. The rating curve was used to calculate discharge for each 5-minute stage value recorded by the datalogger and develop the event hydrograph.

Total suspended solids (TSS) concentration (milligrams per liter) and load (kilograms) were determined for each sample collected. The right hand chart below

shows that TSS concentration was greatest in the first sample and generally decreased through the remainder of the hydrograph. The high initial TSS concentration had little effect on the total TSS load for the event due to small discharge values. TSS load was greatest (3,200 to 3,300 kg) near the peak of the hydrograph. Contaminant transport associated with or adsorbed on TSS would also be greatest near the peak discharge of event runoff. Total TSS load for the event was 12,309 kg.

This study demonstrated that automated tracer injection and collection during a storm runoff event can be successfully used to develop stage-discharge rating curves and to estimate contaminant mass transport during short events in arroyo streams with difficult accessibility or complex cross-sectional morphology.

This article is LANL report no. LAUR-06-7338. Contact Mike Meyer at [email protected].

Dye test collection site contains datalogger (end of bridge) and sampler (round container).

January/February 2007 • Southwest Hydrology • �

ON THE GROUND (continued)

Isotope Measurements Help Estimate Recharge Distributions in the Verde River Watershed Jeannie R. Bryson, Kyle W. Blasch, and John P. Hoffmann – U.S. Geological Survey Arizona Science Center

In 1999, the U.S. Geological Survey began a cooperative investigation with the Arizona Department of Water Resources to help quantify the hydrologic system of the upper and middle Verde River watersheds in north-central Arizona (Blasch et al., 2006). These watersheds encompass an area of about 5,000 square miles (see map) and range in elevation from around 3,000 to 12,000 feet. As part of this study, precipitation samples were analyzed for stable isotopes of oxygen and hydrogen (δ18O and δ2H) in order to determine the local meteoric water line (LMWL), seasonal variations in isotopic values, and isotopic gradients with elevation. This information was used

in conjunction with stable isotope data of groundwater to estimate seasonality and areal distributions of recharge.

Establishing the New LineTwenty-five rainfall and snowfall samples were collected between July 2003 and January 2005 from 11 stations at elevations ranging from 3,100 to 9,100 feet. Sample collections were timed to isolate the summer North American monsoon from winter frontal-storm precipitation. Seasonal

Precipitation and snowfall collection sites in the upper and middle Verde River watersheds (elevations of sites in feet).

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10 • January/February 2007 • Southwest Hydrology

composite samples were created with precipitation contributions from each of the events within a season. Stable isotope samples were analyzed by the USGS Isotope Fractionation Project Laboratory in Reston, Virginia, and at the University of Arizona’s Laboratory of Isotope Geochemistry-Environmental Isotope Research.

Isotope compositions are reported as deviations from an international standard, the Vienna Standard Mean Ocean Water (VSMOW). Values are expressed in parts per thousand or per mil using standard delta notation. Values of δ18O and δ2H in worldwide fresh waters are shown to be linearly correlated on the Global Meteoric Water Line (GMWL), defined by

δ2H = 8.13 δ18O + 10.8 per mil

using data from all stations in the Global Network of Isotopes in Precipitation (GNIP) database (Craig, 1961; Rozanski and others, 1993).

The Flagstaff Meteoric Water Line (FMWL) is the local relation derived from samples collected by the International Atomic Energy Agency at a station in Flagstaff, Arizona (IAEA/WMO 2001; see chart) from 1962 to 1974. It is defined by

δ2H = 6 δ18O + 14 per mil.

The LMWL for the upper and middle Verde River watershed study area developed from the 2003-2005 data is defined by

δ2H = 7.48 δ18O + 9.15 per mil.

Stable-isotope values for winter precipitation samples are significantly lower than for summer precipitation samples (see chart above), reflecting temperature conditions during precipitation.

The relation of stable isotopic ratios to temperature also translates into a relation to elevation: stable isotope values decrease with increasing elevation. Measured stable-isotope elevation gradients for the study remained nearly constant between years and seasons. IAEA stable-isotope values spanning a 14-year period were

used to calculate average stable-isotope values at an elevation of 7,020 feet. The 14-year mean δ2H and δ18O values for the Flagstaff site were -41 and -4.2 per mil, respectively, in the summer and -80 and -11 per mil, respectively, in the winter.

Long-term stable-isotope values were calculated for elevations within the Verde watershed by using the measured gradient during this investigation and the IAEA stable-isotope values at 7,020 feet. The resulting elevation gradient is described by the following equations (z is elevation in meters):

δ2H = -0.019z – 39.04 per mil

δ18O = -0.0026z – 5.36 per mil.

Implications for RechargeUsing the average isotopic values of the groundwater from the subbasins within the watershed, these relationships were used to estimate the contributing recharge areas for subbasins within the watershed (Blasch and Bryson, in press). For example, in the Little Chino subbasin of the upper Verde River watershed, recharge to groundwater comes from precipitation falling at elevations greater than about 5,250 feet, while in the Big Chino subbasin, recharge comes primarily from precipitation falling at elevations

greater than 6,230 feet. In the middle Verde River watershed, precipitation falling at elevations greater than 6,900 feet is the predominant contributor to recharge. In addition, isotope values for groundwater from the entire watershed indicate that about 95 percent of the recharge occurs from winter precipitation.

The LMWL and stable-isotope elevation gradients are useful tools for determining groundwater flow paths to the Verde River as well as locating potential areas of recharge to each subbasin.

Contact Jeannie Bryson at [email protected].

ReferencesBlasch, K.W., and J.R. Bryson, in press.

Distinguishing sources of ground-water recharge by using δ2H and δ18O; Journal of Hydrology.

Blasch, K.W., J.P. Hoffmann, L.F. Graser, J.R.Bryson, and A.L. Flint, 2006. Hydrogeology of the Upper and Middle Verde River Watersheds of Central Arizona, USGS Scientific Inv. Report 2005-5198, 101 p.

Craig, H., 1961. Isotopic variations in meteoric waters, Science, 133: 1702-1703.

IAEA/WMO, 2001. Global Network of Isotopes in Precipitation: The GNIP Database. Accessible at: HTUisohis.iaea.orgUTH.

Rozanski, K., L. Araguás-Araguás, and R. Gonfiantini, 1993. Isotopic patterns in modern global precipitation, in Continental Isotope Indicators of Climate, ed. by P. K. Swart, K. C. Lohman, J. MacKenzie and S. Savin, American Geophysical Union Monograph 78.

ON THE GROUND (continued)

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Stable isotope values in precipitation collected in the study area (LMWL) compared to the Global Meteoric Water Line (GMWL) and meteoric line for precipitation collected at the IAEA station in Flagstaff, Arizona (FMWL).

January/February 2007 • Southwest Hydrology • 11

EPA’s Streamlined Pesticide Approval Rejected In late August, a federal judge determined that a 2004 regulation that had streamlined the U.S. Environmental Protection Agency’s approval process for pesticides violated the Endangered Species Act and overturned the ruling. The 2004 regulation “allowed the EPA to bypass the U.S. Fish and Wildlife Service (FWS) in order to shorten the years-long process of reviewing whether each pesticide posed danger to any of the nation’s 1,200-plus endangered species,” reported the Los Angeles Times. With the ruling, the pre-2004 standards were restored.

The ruling was made by U.S. District Judge John C. Coughenour. Although he recognized that reinstating the FWS review would be “a task of gargantuan proportions,” the Times quoted him, he stated that protection of species is critical, and the Bush Administration was “arbitrary and capricious” in allowing EPA to bypass the FWS review, resulting in a “total absence of any technical and scientific evidence to support or justify” the approval process.

According to the Times, the ruling was a victory for the nine environmental groups that sued the U.S. Department of Interior following the 2004 ruling, which had been heavily endorsed by pesticide manufacturers.

Visit www.latimes.com.

EPA: Can’t Meet the Target? Change ItA mid-year report on water system compliance by the EPA Office of Water found that the percentage of the population served by community water systems that receive drinking water which meets all applicable health-based drinking water standards was 88.4 percent, below the 2006 objective of 90.9 percent. The agency did not expect to meet the target by the year’s end for several reasons,

including “significant annual population impacts from the largest water systems” and difficulties in meeting microbial and microbial-disinfection standards by small systems. Small systems, particularly in Native American communities, were also having difficulty recruiting and retaining certified operators, according to the report.

The report stated that attainment of the “ideal” goal of 95 percent compliance by 2008 “will be a major challenge.” Thus, it proposed to reduce the target to 91 percent by 2011, “a more realistic level, not the ‘ideal’ level of performance which has been set in the past.”

On the positive side, the report noted that compliance increased from 79 percent in 1993 to recent levels of near 90 percent, despite increasingly stringent standards.

EPA’s mid-year report (July 2006) is available at www.epa.gov/water/waterplan/documents/FY06_midyear_report.pdf.

Internal EPA Bickering on Analytical Integrity FindingsIn September, the U.S. EPA Office of the Inspector General (OIG) released a draft report, “Promising Techniques Identified to Improve Drinking Water Laboratory Integrity and Reduce Public Health Risks,” the product of a review to identify vulnerabilities in drinking water sample analysis processes and offer means to reduce them. The review was performed in response to an increase in cases of laboratory fraud noted by OIG’s Office of Investigations between 2000 and 2003.

According to the report, hundreds of vulnerabilities not addressed by EPA’s laboratory certification procedures were identified within the drinking water sample analysis process. These vulnerabilities can compromise the quality of data produced, and thus the perceived public health risk. The report concluded that states that have implemented new techniques to detect laboratory integrity problems have found additional deficiencies, inappropriate procedures, and even cases of fraud.

Report recommendations included specific reforms to laboratory oversight processes, policy, guidance, and training. In addition, the report recommended that EPA’s Office of Water (OW) improve awareness of the vulnerabilities and realities of fraud and inappropriate procedures affecting drinking water data quality. Further, it stated EPA’s Office of Environmental Information should develop a mechanism to identify and a policy to address data in EPA databases from laboratories under investigation, indictment, or conviction.

OW responded with “significant concerns with some of the findings on the part of the OIG related to the role that OW has played to date in dealing with such activity.” OW’s response noted that OIG was unable to quantify the extent to which laboratory fraud is a problem, and that no waterborne disease outbreaks have been directly tied to cases of inappropriate laboratory procedures. Further, OW said OIG’s report does not adequately distinguish between possibilities and likelihood of fraud, and as a result may present an unnecessarily alarming view of the situation. OW also stated that while many of the vulnerabilities noted in the drinking water sample analysis process could and would be addressed through modifications in its laboratory certification program, vulnerabilities in sample collection procedures and fraud detection are outside its purview.

The 77-page report (2006-P-00036), including comments by OW and OEI, is available at www.epa.gov/oig/reports/2006/20060921-2006-P-00036.pdf.

Desal, Forbearance, Storage in Reclamation’s 2007 Plan Among the activities set forth in the U.S. Bureau of Reclamation’s 2007 operations plan are testing the Yuma Desalting Plant (YDP), a forbearance program with farmers, and construction of a new storage reservoir.

Following a 2005 report to Congress describing the feasibility of operating the YDP, including options that would

GOVERNMENT


minimize the impact of operations on the Cienega de Santa Clara, a 90-day demonstration operation of the plant is scheduled to begin in March 2007. The plant will operate at about 10 percent of capacity, allowing about 3,000 acre-feet of water to be stored in Lake Mead as a result of recovered bypass flows during 2007.

Continuing its water savings programs from 2006, Reclamation will participate in arrangements with irrigation districts and farmers in the Lower Basin, whereby farmers are paid to fallow their land and the unused water is stored in Lake Mead for future use.

Based on a 2004 Reclamation study recommending construction of additional storage near the All-American Canal, the Drop 2 Reservoir is now in the engineering design and environmental compliance and permitting stage. Construction is scheduled to begin in 2007 and be completed by 2009. The small, 8,000-acre-foot reservoir is being designed to capture extra water in the system that would otherwise flow to Mexico, particularly during storm events.

The 37-page draft report is available at www.usbr.gov/uc/water/rsvrs/ops/aop/aop07_draft.pdf.

Agreement Initiates San Joaquin River RestorationAs part of one of the West’s largest river restoration efforts, the Natural Resources Defense Council (NRDC), Friant Water Users Authority (FWUA),

and the U.S. departments of Interior and Commerce announced in September an agreement to restore water flows for salmon in the San Joaquin River below Friant Dam near Fresno, California.

The settlement ends an 18-year legal dispute over the operation of Friant Dam and resolves longstanding legal claims brought by a coalition of conservation and fishing groups led by NRDC. It provides for substantial river channel improvements and sufficient water flow to sustain a salmon fishery upstream from the confluence of the Merced River tributary, while providing water supply certainty to Friant water contractors.

Historically, central California’s San Joaquin River supported large salmon populations, including the southernmost Chinook salmon population in North America. Since Friant Dam became fully operational in the late 1940s, approximately 60 miles of the river have dried up in most years, eliminating salmon above the river’s confluence with the Merced River.

Restoring continuous flows to the river will take place in phases. Planning, design work, and environmental reviews will begin immediately, and interim flows for experimental purposes will start in 2009. The flows will be increased gradually over the next several years, with salmon being re-introduced by December 31, 2012. The settlement continues in effect until 2026, with the U.S. District Court retaining jurisdiction to resolve disputes and enforce the settlement. After 2026, the

court, in conjunction with the California State Water Resources Control Board, would consider any requests by the parties for changes to the restoration program.

Funding for the projects will come from several sources, including current environmental contributions from farmers and cities served by Friant Dam, state bond initiatives, and authorization for federal contributions.

Visit www.usbr.gov/mp/, www.fwua.org, and www.nrdc.org.

Feds Drop Protest to SNWA Transfer; Challenges Remain The day before hearings at the Nevada Office of the State Engineer began last September, agencies of the U.S. Department of Interior reached an agreement with the Southern Nevada Water Authority (SNWA) regarding the water agency’s proposed transfer of 90,000 acre-feet of groundwater annually from White Pine County in rural Nevada to the Las Vegas area, reported the Las Vegas Sun. The agreement, involving Fish and Wildlife, National Park Service, Bureau of Land Management, and Bureau of Indian Affairs, calls for SNWA to monitor the county for impacts from pumping and to mitigate “unreasonable” effects in Spring Valley, located in the county. In addition, according to the Sun, SNWA also must avoid any impact from its actions to Great Basin National Park under the agreement.

As expected, ranchers, environmental groups, and rural communities in

continued on next page

HydroFactsPercent of global CO

2 emissions absorbed by forests: 25

Percent CO2 projected to be absorbed by forests stressed by climate

change-related drought: 20

Days in 1970 that northern Alaska was cold enough to operate oil-drilling machinery without damaging the tundra : 213 Days in 2002 that it was cold enough : 106

Current annual loss in Greenland’s ice cap: 27 cubic miles

Annual loss in ice cap during the 1990s: 0 cubic miles

Longest continuous record of temperature measurements: since 1659 in the English Midlands of central England

Estimated increase in rainfall due to urban heat island effect in Phoenix, Arizona: 12-14%

Estimated cost of aggressive reductions in greenhouse gas emissions: 1% of global GDP

Estimated cost of unabated climate change: 5-20% of global GDP

Source: SAHRA’s Global Water News Watch


GOVERNMENT (continued)Nevada and Utah were displeased by the agreement. Bob Fulkerson of the Progressive Leadership Alliance of Nevada, speaking to the Sun on behalf of the opposition, said they were “incredibly disappointed for [the federal agencies] abrogating their responsibilities to the environment of this state.”

SNWA was pleased that some of the opposition was removed, reported the Sun, but said that the agreement would not change the agency’s position that the transfer would provide considerable benefits in terms of economic growth and buffer from drought, and that it could be performed without environmental harm.

While this agreement meant that the Office of the State Engineer would not have to address protests by the federal agencies, the office still must determine whether or not to approve the proposed transfer.

During the hearings, which concluded in late September, Mike Turnipseed, the recently retired state engineer, was “asked whether the law states that the engineer can grant pumping rights if there’s a way to mitigate problems created for existing wells, or whether it states an application can’t be granted if it’s going to interfere with the existing rights,” reported the Sun. His answer: “The latter.”

Under additional questioning described in the Sun, Turnipseed stated that he knew of no state engineer-ordered shutdown of approved pumping wells if they began to conflict with existing rights, prompting the hearing officer to comment that even if SNWA made such a promise, “given the state’s history, ‘does it really ring true?’” Further, the paper said, although Turnipseed suggested that “municipal water agencies should be given ‘more latitude’ than other applicants for water-pumping rights,” he admitted that “Nowhere in Nevada law does it say that municipal use is the highest and best use.”

Current State Engineer Tracy Taylor must weigh the evidence presented during the hearings and decide

whether, and under what conditions, to approve the water transfer. His ruling is expected some time in 2007.

Visit www.lasvegassun.com and www.snwa.com.

“Save Walker Lake” Discussions Breaking DownWalker Lake, a terminal deep-water lake located in western Nevada, has been impacted by diversions and pumping for more than a century and its water level is now 150 feet lower than 120 years ago (see Southwest Hydrology, July/Aug 2004). Decreed water rights exceed average inflow and native fish can no longer survive in its increasingly saline waters.

A number of groups have been working to save the lake from this slow “death,” but frustrated by a lack of results, several recently dropped out, reported the Las Vegas Sun. Among them are the Walker River Paiute Tribe, Mineral County, and the Walker Lake Working Group. Still remaining in the effort are the states of Nevada and California, the Walker River Irrigation District, Lyon (Nevada) and Mono (California) counties, and the federal government, the paper said.

Simeon Herskovits of the Western Environmental Law Center told the Sun that “by dropping out, Mineral County and the working group can push ahead with a pending lawsuit in U.S. District Court, Reno, aimed at mandating increased water flow into Walker Lake.” The two groups had been reluctant to take action that could upset ongoing negotiations, but since no progress was apparent, they decided to pursue an alternative course.

The Sun reported that Nevada Senator Harry Reid has introduced federal legislation to provide $88 million to restore Walker Lake. Herkovits told the paper that the negotiation breakdown would not impact that legislation.

Visit www.lasvegassun.com.

San Juan-Chama Water Contracts Signed in NMPermanent contracts, decades in the making, were signed in September for San Juan-Chama Project water by several New Mexico cities and counties, a ski area, New Mexico Governor Bill Richardson, and the U.S. Bureau of Reclamation, reported The [Santa Fe] New Mexican.

The project diverts water from the San Juan River by tunnel under the Continental Divide into the Chama River in northern New Mexico, which drains into the Rio Grande, from which the users will draw their claim. According to The New Mexican, the project provides more than 96,000 acre-feet of water per year, managed by Reclamation through contracts with some 15 counties, cities, and tribes. Among the largest users are Albuquerque and the Middle Rio Grande Conservancy District, both with permanent contracts dating to the 1970s. The newest contractors include the cites of Santa Fe, Espanola, and Los Lunas; Santa Fe and Los Alamos counties; and Taos Ski Valley. Most will use their new water security for economic growth, the newspaper said.

Although the contracts are signed, the security of the supply is conditional on two factors, reported The New Mexican. First, although analyses by the New Mexico Interstate Stream Commission determined that the San Juan-Chama system is likely to consistently be able to meet the contract terms, in the case of prolonged drought, these new users will need to share water shortages. Second, the Navajo Nation Water Rights settlement, signed by New Mexico and the Navajo Nation last year, still requires $700 million in federal funding over the next 15 years. The settlement guarantees water rights to the tribe while protecting newer rights holders, including those of the San Juan-Chama project. If the funding does not come through, reported the newspaper, the settlement could break down, resulting in the tribe potentially claiming all San Juan River water.

Visit www.sfnewmexican.com.

1� • January/February 2007 • Southwest Hydrology

During a recent meeting, a colleague remarked, “What do you really need to tell people

about climate change and water? It’s getting hotter. We’ll get less snow. The snow will melt earlier. That’s all you need to say.” “Oy, vey! You mean my entire career boils down to three short sentences?” I replied.

Those glib remarks, of course, are built upon a foundation of over a decade of study by my colleague and several decades of studies by many others. At face value, those remarks are the take-home message of this article. However, looking beyond the face value, there really is more to say and the ramifications will differ depending on the reader’s hydrologic, operational, or managerial specialty.

The Big PictureHistorical climate observations reveal changes in the composition of our winter precipitation and the timing of spring snowmelt, both of which strongly influence the Southwest’s surface water supplies and soil moisture levels. Compared with the mid-20th century, more of our winter precipitation now falls as rain rather than snow at lower-to-middle elevations (below 9,000 feet). The major pulse of spring snowmelt occurs earlier than it did during the

mid-20th century (see page 26). Both of these changes relate to well-documented increases in temperature. Change is seldom limited to a single part of the hydrologic cycle, watershed, or ecosystem. It reverberates throughout the system. Temperature increases and earlier

snowmelt have also been correlated to landscape-scale die-off of conifers in the West, as well as increases in the timing and duration of wildland fire. What’s more, non-native vegetation seems to love disturbance, which fosters its easy establishment and can give it a competitive advantage over some native species.

What Do Observations Really Show?Tree-ring and other paleoclimatic records show that long-term droughts more severe than historical droughts occurred in combination with higher-than-average temperatures during a period commonly referred to as the Medieval Warm Period, roughly 900 to 1300 A.D. The combination of high temperature and increased aridity during that period is

seen as a possible analog for the effect of increased temperature in a warmer Southwest. On the other hand, the Colorado River sustained what is probably its lowest flow in the last 500 years during the relatively cool mid-1800s. These inconsistent responses of precipitation to temperature highlight the challenge in predicting future changes in overall precipitation with high confidence—but they clearly show the region could face long-term droughts more severe than those observed in the last century or so.

A rapid and sustained rise in temperature during the 20th century is the most striking feature of reconstructions of temperature and precipitation spanning the last 1,400 years for the southern Colorado Plateau. And temperature is a hydrological variable, particularly in light of our reliance on snow for regional water supplies. Instrumental records of temperature, precipitation, and snow from the past century through today conclusively demonstrate that ongoing temperature increases are linked to: • decreases in snow-water equivalent at

lower elevations (below 6,000 feet); • measurable trends toward a greater

fraction of winter precipitation falling as rain rather than snow; and

• significant trends toward an earlier pulse of snowmelt-driven streamflow.

Gregg Garfin and Melanie Lenart — Climate Assessment for the Southwest, University of Arizona

The certainty of the temperature increase trumps the uncertainty of precipitation changes.

Effects on Southwest Water Resources


In the Southwest, these trends are generally strongest toward the Sierra Nevada and most pronounced at mid-elevations (6,000 to 9,000 feet). Natural causes, such as multi-year to multi-decade variations in Pacific Ocean-atmosphere interactions, play a role in these trends, especially in the Lower Colorado and Rio Grande basins. However, a large fraction of these trends closely relate to temperature increases that cannot be accounted for by historically observed natural climate variability, especially in the headwater regions of our lifeblood rivers: the San Joaquin-Sacramento, the Colorado, and the Rio Grande.

The Certain, the Less Certain, and the UglyClimate scientists have developed realistic general circulation models (GCMs) that simulate global atmosphere and ocean circulation at fine temporal scales (as small as three hours) based on some of the fundamental physics of the land-ocean-atmosphere system. These models produce plausible results, consistent with our understanding of climatology, and they are good at simulating most observed features of the land-ocean-atmosphere system. What these models do really well is simulate the earth’s radiation balance, at relatively coarse spatial resolution, and changes to the radiation balance from natural and human atmospheric inputs. What the global models do not do well is simulate fine spatial-scale processes, watershed-scale precipitation, the precise timing of phenomena like the monsoon, and any processes that require realistic topography to produce realistic results. Predicting the influence of cloud cover, which can reduce incoming solar radiation yet retain outgoing heat, also remains challenging.

Scientists compensate for some of the limitations of the GCMs by feeding their output into regional climate models that have much finer spatial resolution and more accurate topography. Another strategy to compensate for spatial coarseness in GCMs is to use statistical relationships developed from observational data to estimate climate parameters at

finer spatial scales. For instance, increases in elevation lead to relatively predictable decreases in temperature and increases in precipitation compared to sea level.

The average predictions of 18 of the latest and greatest climate models show annual temperature increases of 4 to 5°F throughout the Four Corners states and Nevada by mid-century (2046-2055), as described in more detail by Hoerling (page 18). Such increases are consistent with observed increases in temperature, especially since the 1970s, and with our

understanding of radiative effects of greenhouse gas increases. Modeled

precipitation projections for

the 21st century,

however, diverge considerably, although annual precipitation decreases by mid-century are anticipated for the Lower Colorado River Basin (CRB).

Studies that synthesize information on western snowpack, streamflow timing, and CRB hydrology indicate that projected temperature increases will severely strain water resources in the basin. By mid-century, the main pulse of spring snowmelt runoff in the Upper CRB is expected to come approximately two weeks earlier than at present. By the end of the century, snowmelt runoff is expected four weeks earlier in virtually all of the six southwestern states. Runoff is also expected to decrease, in part due to the higher evaporation rates that come with higher temperatures. With a decrease in runoff, storage and power generation would decrease, unless changes in allocation and demand can compensate for present stresses on the system.

The basic message of these studies is that the certainty of the temperature increase trumps the uncertainty of precipitation changes. Warming oceans contribute to the growing expectation for more frequent El Niño events, which tend to boost winter and spring precipitation in the Southwest, as well as spring temperatures. Overall, though, temperature increases

see Effects, page 34

Retreating glaciers, such as McCarty Glacier in Alaska, shown here in 1909 and 2004, dramatically illustrate the effects of warming on the hydrologic cycle. Source: USGS photo library, Robert A. Rohde, and Global Warming Art (www.globalwarmingart.com).

1909

2004

Current storage capacities in northern and southern California reservoirs and the Sierra snowpack. A 3°C increase in temperature is projected to result in a 4- to 5-million-acre-feet (maf) decrease in Sierra snowpack from its current 14 maf capacity (from the California Department of Water Resources).

11 MAF reservoir storage

13.5 MAF reservoir storage

14 MAF snowpack storage

Illust

ratio

n: M

ike

Buffi

ngto

n


Nobody relishes being “past peak” anything. Whether it’s the prime of our human existence

or the prime of Nature’s abundance, the notion of having less rather than more is often vehemently denied. But demand growth in the face of production and storage decline has severe consequences, especially when existing uses already consume the available supply.

The lifeblood of the Southwest is the Colorado River, which is increasingly impacted by climate forces not previously experienced. The recent drought prompts concern among water users and water stewards alike, and requires the scientific community to probe whether a sustained threat is rising to our already perilous moisture balance. The consensus of the Intergovernmental Panel on Climate Change (IPCC, 2001) affirms that Earth’s atmosphere is accumulating unprecedented quantities of carbon dioxide that are now causing detectable increases in surface air temperature.

Is this ongoing drought an early warning sign of something other than the historical norm, and the gateway to a future climate with more severe drought hazards? What is known about the sensitivity of moisture conditions in the Southwest to a changing climate? To seek answers to these questions, we have undertaken a systematic analysis of a new suite

of climate model simulations from the arsenal of tools contributing to the 2007

IPCC Fourth Assessment Report (AR4). What is the news for the Southwest?

A New Drought StudyA common practice in drought monitoring is to derive a meteorological quantity known as the Palmer Drought Severity Index (PDSI; Palmer 1965). The index calculates the cumulative effects of precipitation and temperature on surface moisture balance. Water storage is solely derived from a two-layer soil system, with no explict accounting for deep groundwater or water in manmade surface storage. Drought develops when evapotranspiration exceeds the supply available from precipitation and soil moisture relative to a region’s “normal” water balance. The index ranges from -4 (extreme drought) to +4 (extreme moistness).

Reservoir storage is key for assessing water supply during the course of a year in the Southwest, and is not included

in a PDSI drought monitor. However, when monitoring drought conditions on annual time scales, streamflow is strongly correlated with annual PDSI. The relationship between the annual virgin flow (the estimated flow of the stream if it were in its natural state and unaffected by the activities of man) at Lees Ferry, Arizona, and the PDSI averaged over the upper Colorado Basin drainage is

FLOW = Ao + (A1 x PDSI)

for FLOW greater than the estimated basal flow of 3 million acre-feet (maf).Using data from 1895-1989, the linear regression coefficients are

Ao = 14.5 maf, A1 = 1.69 maf.

During the 95-year reference period, annual PDSI explains 63 percent of the annual river flow variations at Lees Ferry.

Post-1989 data offer an independent period to confirm applicability of the above relation for predicting Lees Ferry flow. This period is one of warming temperatures, allowing us to test the prediction equation’s fidelity in an environment of climate change. For 1990-2005, PDSI predicts 85 percent of the recent yearly fluctuations of flow at Lees Ferry, including the low flow regime during the recent drought.

To determine the probable hydrologic consequences of future climate change, the above formula was used to downscale

Even several of the wetter runs yield increasing drought due to the overwhelming effect of heat-related moisture loss.

Martin Hoerling – NOAA Earth System Research Laboratory and Jon Eischeid – University of Colorado, CIRES


future PDSI to Lees Ferry streamflow. The monthly PDSI was calculated for each of 42 climate simulations spanning 1895 to 2060, using multiple runs of 18 different coupled ocean-atmosphere-land models. The models were forced with the known changes in atmospheric constituents and solar variations from 1895-2000 and a business-as-usual assumption for future carbon emission after 2000.

A Drastic Change in the Character of Drought Sustained drought of severe intensity (PDSI < -3) occurred during 1953-1956, an event rivaled during 2000-2003. The average annual Lees Ferry flow was only 10 maf during both events, but the recent drought bears different properties than its predecessor. In particular, abnormally high temperatures have been more prevalent during the 2000-2003 drought, with the West nearly 1°C warmer than during the 1950s drought.

Climate simulations of PDSI for two near-term 25-year periods (2006-2030 and 2035-2060) show an increase in drought severity (relative to their 20th century “normals”) that occurs in lockstep with surface warming (see figures, above right). Little net change in precipitation occurs in the average of all models, though variability among the simulations is considerable. Nonetheless, even several of the wetter runs yield increasing drought due to the overwhelming effect of heat-related moisture loss. The Southwest appears to be entering a new drought era. In the 20th century, drought was principally precipitation driven, and enhanced by temperature. Indications from the simulations are that a near perpetual state of drought will materialize in the coming decades as a consequence of increasing temperature.

To place these probable changes into context, projections for the next quarter century paint a sober landscape in which average PDSI equates to the 2000-2003 drought conditions. This occurs as the consequence of surface water loss due to increased evapotranspiration owing to an average 1.4°C warming (relative

see Past Peak, page 35

Palmer Drought Severity Index (PDSI). Values less than -3 denote severe drought conditions. Left panels illustrate the 4-year average drought conditions experienced during the 1950s drought and the recent drought. Right panels are future projections of the PDSI based on 42 simulations conducted to support the Fourth Assessment Report of the IPCC. By about 2050, average moisture balance conditions will mimic conditions experienced only rarely at the height of the most severe historical droughts.

Historical Future

1953 — 1956 2006 — 2030

2000 — 2003

PDSI-6 -5 -4 -3 -2 -1 1 2 3 4 5 6

2035 — 2060

January/February 2007 • Southwest Hydrology • 1�

Policies relating to climate change have historically been articulated primarily by the federal

government. Recently, however, some states have begun setting their own policies that augment the existing federal framework, particularly focusing on the areas of greenhouse gas reduction and improving resiliency to climatic extremes.

The Federal FrameworkThe Global Change Research Act of 1990 authorized the U.S. Global Change Research Program to “provide for the development and coordination

of a comprehensive and integrated United States research program which will assist the nation and the world to understand, assess, predict, and respond to human-induced and natural processes of global change.”

In fiscal 2001/2002, federal agencies’ climate-related activities were refocused through creation of the Climate Change Research Initiative, Climate Change Science Program (CCSP), and Climate Change Technology Program. The Science Program was intended to integrate the federally supported research on climate and global change administered by 13 federal agencies. Similarly, the Technology Program addresses research and development of technologies associated with reducing, avoiding, or sequestering greenhouse gas emissions.

According to CCSP, the federal research programs have invested almost $20 billion in climate change and global change research since the inception of the Global Change Research Program. The investment in research has resulted in significantly improved capabilities in areas such as climate modeling.

CCSP adopted a 2003 Strategic Plan that set forth five major goals for the program. Two of those goals are particularly relevant to water and natural resource managers:

• CCSP Goal 4: Understand the sensitivity and adaptability of different natural and managed ecosystems and human systems to climate and related global changes.

• CCSP Goal 5: Explore the uses and identify the limits of evolving knowledge to manage risks and opportunities related to climate variability and change.

Recent Interstate DevelopmentsIn June 2006 the Western Governors’ Association (WGA), which represents 19 states and three territories, adopted a report, “Water Needs and Strategies for a Sustainable Future,” which recommended focusing on climate vulnerabilities and building increased resiliency to climatic extremes. Specific recommendations included:

• WGA should urge CCSP to fund research for improving climate change predictive capabilities, and for assessment and mitigation of climate change impacts. Specifically, the federal government should implement research funding recommendations associated with CCSP Strategic Plan Goals 4 and 5, including increasing partnerships with users such as resource management agencies, states, and local governments.

• States should include climate change scenarios in their water-related planning (state water plans, watershed plans, drought plans), and should include local governments in climate change planning efforts.

• States should evaluate their legal frameworks for water management and revise them as necessary to ensure sufficient flexibility for responding to climate change.

• The governors should convene ongoing meetings between water managers and the scientific community to foster exchange of information on research outcomes and research needs.

The Western States Water Council is presently preparing workplans for implementing the WGA report on behalf of the governors. The WGA report follows

Jeanine Jones – California Department of Water Resources

Emerging State Policieson Climate Change


an earlier partnership launched in 2003 by the governors of California, Washington, and Oregon, known as the West Coast Governors Global Warming Initiative. In that effort, the governors approved a series of recommendations on subjects such as reducing greenhouse gas emissions and increasing energy efficiency. Examples of ongoing state actions related to the initiative are described below.

On the opposite side of the country, seven governors from northeastern states signed a 2005 memorandum of understanding to implement a Regional Greenhouse Gas Initiative for reducing greenhouse gas emissions from power plants. The initiative calls for implementing a multi-state emissions cap and trade program, initially focusing on carbon dioxide emissions. Key provisions of the effort include an agreement to stabilize carbon dioxide emissions from the region’s power plants at current levels from 2009 to early 2015, followed by a 10 percent reduction in emissions by 2019.

Two State-Specific ExamplesIn 2005, California Gov. Arnold Schwarzenegger signed an executive order setting greenhouse gas reduction targets for the state and directing state agencies to prepare a report on global warming impacts in California. The report, to be updated biannually, was to cover impacts, including “impacts to water supply, public health, agriculture, the coastline, and forestry,” and was to include mitigation and adaptation plans to combat identified impacts.

Greenhouse gas reduction targets were subsequently set by statute through adoption of legislation in 2006 requiring development of regulations providing for mandatory reporting and verification of greenhouse gas emissions and limiting, by 2020, emissions to the level estimated to have occurred in 1990.

California’s state agency Climate Action Team finalized its initial report to the governor and to the state legislature on impacts of global change in March 2006. The report is available at California’s climate change portal,

www.climatechange.ca.gov. Of particular interest are descriptions of impacts to water resources. For example, the report notes that “although precipitation is projected to change only modestly over this century, rising temperatures are expected to diminish snow accumulation in the Sierra Nevada …By the 2035-2064 period, snowpack in the Sierra Nevada could decrease 10 to 40 percent depending on the amount of warming and precipitation patterns.” The report further notes that, after mid-century, changes in runoff volume and timing reduce the ability of major water projects relying on runoff from the Sierra Nevada to make deliveries to agricultural users south of the Sacramento-San Joaquin River Delta. Detailed technical analyses performed to assess climate change impacts on water supplies are described in a California

Department of Water Resources (CDWR) report (see box below).

In 2006, Oregon’s governor established a Governor’s Climate Change Integration Group, charged with expanding the work of an earlier Governor’s Advisory Group on Global Warming, which had prepared the 2004 Oregon Strategy for Greenhouse Gas Reduction. The Integration Group’s immediate task is to prepare a report to the governor describing how the state should prepare for adapting to climate change impacts. The group also aims to stimulate new research programs on adaptation and mitigation strategies as described in the federal CCSP goals.

Jeanine Jones is the Interstate Resources Manager for CDWR and represents California on the Western States Water Council. All views expressed in this article are those of the author, not of CDWR. Contact her at [email protected].

Regional Downscaling

Model used:

• air temperature• precipitation• wind speed• surface humidity• soil moisture• streamflows

California

SWP-CVP Impacts

Model used:

• reservoir operations• deliveries and exports• reservoir storage• delta outflow

SWP-CVPregion

Global Modeling

Models used:

• air temperature• precipitation• specific humidity• latent heat flux• radiation fluxes• wind speeds

Analysis includes: Analysis includes: Analysis includes: Analysis includes:

Delta Impacts

Model used:

• flow• water level• water quality

Delta

GFDL or PCM VIC CALSIM DSM2

The July 2006 CDWR report focused on methodologies for assessing climate change impacts and on preliminary assessment results for California’s Sierran water supplies. The report is available at baydeltaoffice.water.ca.gov. Briefly, the report’s analyses (shown schematically at left) included downscaling selected global climate model outputs (at a grid of roughly 2 degrees latitude/longitude) through use of a macro-scale hydrologic model that yielded

runoff data at a 1/8th-degree grid. Runoff data were further processed to provide streamflow information for the planning simulation model used to assess impacts on California’s two largest water projects that rely on Sierran runoff: the federal Central Valley Project (CVP) and the State Water Project (SWP). Also evaluated were water quality impacts and sea level rise impacts in the Sacramento-San Joaquin River Delta, and flood management impacts.

CDWR’s impact analysis approach downscaled global model output to assess regional and local impacts (figure courtesy of CDWR).

Progress on Incorporating Climate Change into Management of California’s Water Resources


Severe droughts experienced throughout the Southwest in the past decade have captured the attention

not only of climate scientists: water managers began to rethink their long-term management plans as well. Southwest Hydrology interviewed several water managers from across the region to find out how their agencies are responding to the information coming from climate scientists.

Generally, managers agree that current climate predictions indicate certainty that temperatures will increase in the Southwest, although the magnitude remains unclear, and that both the magnitude and direction of precipitation change is unclear. Charlie Ester, manager of water resources operations at the Salt River Project (SRP) in Phoenix, has seen predictions for both a wetter and drier Arizona. Either way, the variability of climatic conditions is expected to increase. Jeff Johnson, senior hydrologist at Southern Nevada Water Authority (SNWA), said the predictions in his area do not suggest less water so much as changes in the timing and form of precipitation—more rain and less snow. These changes, he said, may be more of a concern in the Upper Colorado River Basin where reservoirs are smaller and may end up spilling more often, as opposed to in the Lower Basin where there is more usable storage.

Using Climate Data to Manage WaterDenver Water is one of the larger water suppliers in the Rocky Mountain

West to actively look at the impacts climate change could have on its system. As part of the recent update of its long-range plan, the utility employed a simple climate change

scenario in order to evaluate safety factors in the plan’s section on water supply risks.

Because climate models show general agreement that temperatures are likely to increase in the Denver region and less agreement about how precipitation amounts might change, Marc Waage, water resources director of Denver Water, said the utility evaluated only a temperature change scenario. Change in streamflow that might occur from various changes in temperature were estimated from an EPA report (Nash and Gleick, 1993) in order to determine the affect on Denver’s water supply. To estimate the change in demand resulting from higher temperatures, the utility used USGS regional climate change studies to estimate the change in evapotranspiration rates for turf. Putting these estimates together, Waage’s group calculated that the result could be as much as a 12 percent decrease in dry year water supply and a concurrent 6 percent increase in water use.

At SRP, the major water provider for the Phoenix metropolitan area, scientists are compiling research and analyses to determine a consensus on the predicted impacts of climate change on the Salt/Verde river system, SRP’s primary water supply. The findings will be used with tree-ring records of historic drought to simulate the future water-supply resilience of the system. In addition, the utility is upgrading its supplemental groundwater pumping capacity to attempt to return to its historic pumping capacity, which had been gradually reduced as urban sprawl isolated the once agriculturally based distribution system.

SNWA used historical precipitation and streamflow data to project likely future conditions in the Colorado River system. However, Johnson admitted that the recent drought was unexpected—the magnitude of variability was not in their projections—consequently, stochastic data will be used in the future to help build in the needed variability. SNWA is less concerned about climate change impacts on their groundwater supplies—currently just 10 percent of their total supply—because climate change effects manifest themselves much more slowly in groundwater than in surface water supplies.

According to Johnson, the value of climate data to SNWA is in showing the need to manage water resources more proactively in that region. Tree-ring studies are revealing the variability that could occur, which might not be captured in current

Water managers will have to deal with greater extremes in the water system.

Betsy Woodhouse – Southwest Hydrology, University of Arizona

CLIMATE CHANGEThrough the Eyes of Water Managers

Elephant Butte Reservoir on the Rio Grande in southern New Mexico near the height of the 2004 drought.


analyses. While the predicted climate changes have not yet caused the utility to make significant changes to current policies or plans, the utility pays close attention to the information that comes out.

Tucson Water is working with the Climate Assessment for the Southwest (CLIMAS) program at the University of Arizona to try to better understand the climate change trends and long-term resource challenges that may potentially develop. In planning for a future of increasing uncertainty and variability in water supplies, Tucson Water is building multipurpose underground storage and recovery facilities to bank excess renewable supplies and provide water for both “normal” years and those times when resource shortages may develop.

Climate Data Wish ListAll utilities would like more certainty about what is going to happen to their particular water source, and no doubt climate scientists would like to be able to tell them. Waage at Denver Water provided a specific list of the kind of information he would like to see in the future:

• More information on what changes in timing and annual volume of streamflow could be expected.

• Better understanding of the changes in precipitation in the West, particularly at the watershed scale.

• A hydrologic model for the basin that incorporates climate data to more carefully analyze the effects of various climatic regimes and potential management strategies.

• Better understanding of what climate change means to watersheds in terms of land cover. This includes the direct effects of vegetation change, as well as indirect effects such as the proliferation of the pine beetles that are killing trees in large regions.

• An unbiased entity to review the climate change arguments used by skeptics and believers alike and objectively evaluate what is known and what is predicted, in order to improve the confidence of upper management to make significant climate change-related operational and management decisions.

At SRP, Ester wants to know how the summer monsoon will respond in a warmer world. If it strengthens, as some predictions indicate, the utility could benefit from increased runoff. Improved understanding of the response of the ecosystem across the watershed to climate change would also be helpful for determining how future runoff may be generated.

Ralph Marra, water resources administrator at Tucson Water, said the increasing importance of Colorado River water as the utility’s primary source of renewable supply means that future climate trends that relate to that watershed are of great interest. Furthermore, improved understanding of possible local climate change trends would help the agency better prepare for changes in the onset of the peak demand season and its duration.

The Bottom LineTony Willardson, associate director of the Western States Water Council, predicts that storage will become the primary

issue related to western water supplies. Whether due to population increase, climate change, Endangered Species Act-related requirements, or other circumstances, water managers will have to deal with greater extremes in the water system. Drought management plans are critical for large facilities, as current projections may not take into account the kind of variability that will be experienced in the future.

The water managers all agreed that the future inevitably will bring greater variability in water supplies. Marra spoke for many in concluding, “As a water provider, our practical and immediate focus needs to be on the near- to mid-terms, but it is important to keep a watchful eye on the long term so that we can maintain flexibility and respond to change.”

ReferenceNash, L.L., and P.H. Gleick, 1993. The Colorado

River Basin and Climate Change: The Sensitivity of Streamflow and Water Supply to Variations in Temperature and Precipitation, prepared for the U.S. EPA, report EPA-230-R-93-009.

Through the Eyes of Water Managers

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Typically, water managers size their infrastructure and plan for floods and droughts by looking

at extremes in the observed record and adding a margin of safety. Observed runoff records go back to the 1950s or, in many cases, earlier decades. The problem is the recent past may not represent what the future holds. This is because climate was more severe at times before the observed record and the future climate is changing.

Managers Should Look Further Back…and AheadThere are two arguments warning water managers not to base their water management decisions solely on observed streamflow, temperature, and precipitation records. One argument holds that prior to the 20th century, climate was more variable and severe than the observed record, as demonstrated by “paleoclimate” reconstructions of streamflows from tree rings and other sources. The second, relatively newer argument holds that our current climate is changing rapidly because of increased greenhouse gases in the atmosphere and this may have far-reaching consequences for water resources planning, thus climate model-predicted changes must be considered.

The relevance of using the paleoclimate record to simulate drought was demonstrated in the Severe Sustained Drought study (Water Resources Bulletin, 1995) in which streamflow reconstructions

from tree rings were used to simulate the impacts of a severe, sustained drought on the Colorado River under current management operations and institutions. Interest in this study was rekindled in recent years when Lake Powell dropped to record low levels in 2002, and storage in Lake Powell from 1998 to 2004 was less than under the severe drought simulation (see www.hydrosphere.com/publications/SSDRedux.htm).

Looking ahead, greenhouse gases are accumulating in the atmosphere, causing a warming of Earth that will affect global and regional climate patterns.

Warming in the Southwest, for example, has already begun and is expected to increase over coming decades, resulting in a snowpack that is smaller and melts earlier (Mote et al., 2005; also see page 26). Warming may also cause changes in precipitation patterns as well, although many aspects of this are uncertain.

These arguments for basing water resources planning on additional information besides the observed record are typically presented separately. This may be because the techniques for estimating each type of change — paleoclimate reconstructions for pre-observed climate and climate models for future climate change — do not mesh easily with each other. However, it is possible to combine both data sets, as a team lead by Stratus Consulting working in concert with the city of Boulder, Colorado, is doing. Although the process is still underway, when complete, it will allow the city to examine potential effects of long-term change in climate imposed on a reconstruction of paleoclimate variability.

Laying the Past Onto the FutureThe National Oceanographic and Atmospheric Administration’s (NOAA)

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Flow for 2002 (adjusted to be consistent with tree ring data) = 32,000 AF

1723 - lowest year based on tree ring evidence = 29,600 AF

Joel B. Smith, Kathleen C. Hallett, and Jim Henderson – Stratus Consulting and Kenneth M. Strzepek – University of Colorado

Measured streamflow was used in conjunction with reconstructed streamflow to recreate a likely tem-perature and precipita-tion record representive of the paleoclimate.

Expanding the Tool Kit for Water Management in an Uncertain Climate

Variability in streamflow reconstructed from tree-ring data for Middle Boulder Creek shows the 2002 drought was comparable to the lowest flow in the 300-year record (from Hydrosphere Inc.).


Office of Global Programs awarded a grant to Stratus Consulting to work with the city of Boulder to examine the city’s vulnerability to long-term climate change and climate variability. The grant builds on an earlier study Boulder undertook with Hydrosphere Inc. to examine the city’s vulnerability to a repeat of a 300-year record of climate variability (see figure, below left). That record was based on a reconstruction of streamflow in Middle Boulder Creek developed by Connie Woodhouse of NOAA’s National Climatic Data Center using data from a tree-ring chronology. Hydrosphere found that the city could cope with the variability indicated in the 300-year record. They also examined a 15 percent reduction in runoff, arbitrarily selected to simulate the effects of climate change, and found such a reduction would cause problems.

Building on this analysis, Stratus Consulting (with Hydrosphere, the University of Colorado, NOAA, and the National Center for Atmospheric Research) is examining how Boulder could cope with the combination of the climate variability indicated by the paleo record and greenhouse gas-induced climate change.

The potential effects of climate change on water resources are typically examined by estimating change in runoff using output from climate models. Changes in meteorological variables such as precipitation and temperature from the models are combined with an observed record to feed into hydrologic models. The difficulty in applying the reconstructed streamflow record is that the prehistoric changes in temperature and precipitation are not obvious. The reconstruction only gives streamflow. Of course, streamflow can be used directly in management models to assess how an exact repeat of the paleoclimate record can affect water management. What is not so clear is how to combine change in climate and the paleoclimate record.

We worked with Balaji Rajagopalan of the University of Colorado to devise a technique to use observed (measured)

see Tool Kit, page 36

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Mountain snow fields act as natural reservoirs for many western water-supply systems,

storing water in snowpacks during winter when most precipitation falls, and releasing it into rivers during the warm season as they melt. As much as 75 percent of water supplies in the western United States are derived from snowmelt, thus, management of western rivers commonly is based on significant spring and early summer runoff to reservoirs and lowlands when water demands for irrigation are greatest. In the winter, water demands are low and the potential is high for storms to cause floods. This temporal separation between cool-season flood risks and warm-season runoff benefits is a fundamental assumption of water-resource management strategies. Thus recent trends toward diminished snowpack and earlier snowmelt threaten those finely tuned water-resource and flood-management systems and procedures.

Describing Streamflow TimingStreamflow timing can be described by different measures depending on data availability and the aspects of greatest concern. Roos (1991) and Dettinger and Cayan (1995) analyzed the fractions of annual streamflow that occur in the spring and early summer, which, in many water-resource systems, is the most readily stored and distributed for warm-season uses. Cayan and others

(2001) characterized streamflow timing by the day of year when wintertime low-flow conditions rapidly transition to springtime high-flow conditions with the onset of warm-season snowmelt. These “spring-pulse dates” are important because they indicate the timing of snowmelt and the divide between winter and spring conditions. Stewart and others (2004) characterized streamflow timing according to the date by which roughly half of the streamflow for a year has passed. Such “center of volume” dates provide direct measures of overall streamflow timing based on runoff conditions throughout the year.

Earlier Flow ObservedAnnual streamflow in most western rivers has come progressively earlier during the past several decades. The long-term tendency of springtime streamflow—that fraction of overall flow that occurs from April to July—to decline during the 20th century in the central and northern Sierra Nevada is shown above right as a fraction of overall flow. Regressions of data indicate no statistically significant trend until 1945, when a trend

toward earlier streamflow begins. As the springtime fraction of yearly flows has declined, the winter fraction, especially in March, has increased, reflecting a regional trend toward warmer winters and springs since the mid-20th century.

Spring Arriving Earlier in Western StreamsA summary of USGS Fact Sheet 2005-3018 and selected articles from the Watershed Management Council Networker, Spring 2005.

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Comparison of mean daily streamflows in the Clark Fork Yellowstone River, Wyoming, during the 1950s and 1990s, with vertical lines marking center-of-volume dates (from USGS Fact Sheet 2005-3018).

April to July streamflow in eight major rivers of the western Sierra Nevada, California, as a fraction of the water-year (October through September) total streamflow. Dots indicate yearly values, blue curve is 9-year moving averages, dashed line is linear trend prior to 1945, and solid line is trend after 1945 (from USGS Fact Sheet 2005-3018).

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Changes in daily streamflow of western rivers are illustrated at bottom left in a comparison of mean measured flows in the Clark Fork Yellowstone River, Wyoming, during the 1950s versus the 1990s. Overall river discharges in these decades were quite similar, with average flow of 27.8 cubic meters per second in the 1950s and 27.9 in the 1990s. In the 1990s, however, springtime flows were larger and late summer flows were smaller than in the 1950s. Thus, flow generally arrived earlier in the recent decade, with an average center-of-volume date about 4 days earlier in the 1990s than in the 1950s.

Change Widespread Across the WestThe geographic extent of the trend toward earlier streamflow in snow-fed streams is shown in the figure below, with timing measured by the center-of-volume dates in rivers throughout western North America. The measurements indicate that flows in many western streams arrive one week to almost three weeks earlier now than in the mid-20th century.

This regional trend developed amid large year-to-year and basin-to-basin variations in both streamflow amount and timing. The variations are due to contrasts in topographies, precipitation patterns, and

snow conditions among river basins. Despite the variations, over 90 percent of the stations with statistically significant

trends have trended toward earlier runoff in western states. The average center-of-volume date for western rivers is about nine days earlier now than in the 1950s.

Natural or Human-Induced Causes?These trends in timing are most readily attributed to winter and spring warming, but that interpretation is complicated by recent variations in precipitation in some areas and by a broad trend toward slightly later precipitation. Causes of these long-term climatic trends remain uncertain. The observed streamflow timing and winter-spring warming trends are consistent with current projections of how greenhouse gases may affect western climates and hydrology; thus streamflow timing and trends may be attributed, in part, to global warming. The climate of the North Pacific Ocean basin, however, underwent a seemingly natural shift toward warmer

conditions in the eastern Pacific and western Americas around 1977. This change was part of a multidecadal cycle of climate fluctuations in the region and has contributed, to an uncertain extent, to long-term climatic and hydrologic changes in the western states during the past 50 years. The cycle shifted back to a cool phase in 1999 but the reversal did not slow the trends toward warmer temperatures or earlier streamflows in most of the West.

Response to Future ConditionsIncreasing concentrations of greenhouse gases in the atmosphere are expected to induce future climate changes beyond those caused by long-term climate variation. Modern climate models uniformly predict warmer temperatures in the West but show little consensus on how precipitation might change. Conservative values for warming and small precipitation changes modeled for the Sierra Nevada showed that even modest climate changes would cause substantial changes in extreme temperature episodes (fewer frosts and more heat waves); substantial reductions in spring snowpack, earlier snowmelt, greater winter runoff, and reduced spring and summer runoff; more winter flooding; and drier summer soils and vegetation with greater fire danger (Cayan and others, 2005).

In the lower reaches of many western watersheds, dams and levees control water movement. The Sacramento-San Joaquin Delta is one area likely to experience climate effects from two directions: increased wintertime flows and floods from upstream, and sea level rises below. Florsheim and Dettinger (2005) determined that the type of fluvial geomorphic changes that occur in the delta—such as erosion, flooding, sedimentation, and levee failures—will depend on how well existing infrastructure survives and what decisions are made about the timing, magnitude, and duration of flow releases from upstream reservoirs. However, the lower delta with its manmade infrastructure appears more vulnerable to climate variations now than under natural conditions.

see Streamflow, page 36

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Trends in centers of volume of yearly streamflow hydrographs in rivers throughout western North America, based on U.S. Geological Survey streamgauges in the United States and an equivalent Canadian streamflow network. Large circles indicate sites with trends that differ significantly from zero at a 90-percent confidence level; small circles are not confidently identified (from USGS Fact Sheet 2005-3018).

The average center-of-volume date for western rivers is about nine days earlier now than in the 1950s.

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Carbon dioxide (CO2) in the atmosphere has increased by over 100 parts per million

since the beginning of the Industrial Revolution, resulting in one of the most unambiguous effects of human activities on the globe. While rising CO2 concentration has implications for atmospheric temperature change due to its greenhouse gas characteristics, it also has significant ramifications for how vegetation functions on landscapes and its ecohydrological consequences. Therefore, a large effort over the past decade has aimed at understanding the coupled ecological and hydrological responses to global change, such as rising CO2 concentrations, temperatures, and alterations in precipitation. Of these, numerous studies have focused solely on how plants and ecosystems may respond to this change in atmospheric composition, giving us confidence to predict vegetation change in the face of predicted future CO2 concentrations and potential feedbacks of the biosphere on the atmospheric change.

Contrasting Scenarios for Rising CO2Carbon dioxide is the primary substrate for photosynthetic energy acquisition by life, the process of using light energy to combine CO2 and water to produce organic compounds. Since photosynthesis is an unsaturated biochemical reaction in plants, rising CO2 concentrations increase photosynthetic rates under current conditions. Studies have shown that this change in photosynthetic rate results in greater above- and below-ground plant growth, especially in water-limited regions. Also, at higher than current ambient CO2 concentrations, plants reduce the apertures of the small pores in their leaves that permit CO2 and water vapor exchange with the atmosphere. These changes in plant function foster

greater growth with less water demand, and the end result is a decrease in whole-plant water use. These alterations in

plant behavior influence the storage of water in the soil surface and scale up to affect the landscape water balance. Thus, through its impacts on plant water use and surface soil water storage, rising CO2 is predicted to increase recharge and streamflow when scaled to landscapes. This is likely to be most profound in areas where evapotranspiration (ET), and thus vegetation characteristics, dominates the behavior of the water cycle (see diagram below).

A second major finding is that the composition of plant communities changes at greater than ambient CO2 concentrations due to differential growth and resource use by the major plant types in a region. For example, several biochemical types of photosynthesis are found in terrestrial plants, resulting in

plants that respond differently to changes in CO2 concentration. C4 photosynthetic species (which initially form four carbon-atom molecules) tend to be less responsive to rising atmospheric CO2 concentration than C3 species. In the southwestern United States, the deeply rooted woody species are predominantly of the C3 photosynthetic type, which also comprises the far dominant plant species on Earth, while the summer-active perennial grasses are dominated by the C4 photosynthetic type. Elevated CO2 concentrations favor woody plants over grasses, and may accelerate woody-plant thickening or encroachment. Changes in the ratio of woody plants to grasses can influence the landscape water balance by affecting recharge and streamflow: larger woody vegetation populations would be expected to increase the amount of water leaving landscapes as ET (see diagram).

Thus, rising CO2 concentration suggests two contrasting water resource scenarios. On one hand, we expect greater plant performance with respect to water use that will increase landscape yield, but on the other hand, changes in vegetation will influence how much water is returned to the atmosphere by evapotranspiration.

Climate Change, Vegetation Dynamics, and the Landscape Water Balance

Travis E. Huxman – University of Arizona and Russell L. Scott – USDA-ARS Southwest Watershed Research Laboratory

Rising CO2 is predicted

to increase recharge and streamflow when scaled to landscapes.

Scale (micro to macro) Response to Increased CO2 Water Balance Effects

Leaf function• increased CO2 concentration within leaf

• partial stomatal closure

↑ leaf photosynthetic rates

↓ leaf water loss

Whole plant function

• increased leaf water-use efficiency

• reduced plant stress and better function during water deficit

↓ plant water use

↑ plant growth or season length

Vegetation dynamics

• biomass allocation shifts more to above-ground plant structure

↑ canopy leaf area↓ active rooting area

• C3 plant species favored over C4

↑ abundance of woody plants compared to grass

System water balance

(competing scenarios/ outcomes)

↓ H20 loss through evapotranspiration greater soil H20 storage / yield

↑ H20 loss through evapotranspiration less soil H20 storage / yield

Vegetation impacts on water balance due to rising atmospheric CO2 concentration. At larger scales, two different scenarios emerge, one that would provide greater water and the other providing less water.

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Unfortunately we cannot experimentally manipulate atmospheric CO2 at sufficient spatial scales to directly test these two hypotheses. Instead, parallel research programs have been developed at different spatial and temporal scales. First, small-scale experimentation has focused on plant and plot-scale water balance responses to CO2 concentration manipulation for the development of mechanistic models. Second, landscape studies have been expanded to evaluate natural vegetation variation and processes associated with vegetation change. The overall goal is to develop the appropriate ecohydrological framework and landscape context in which to undertake small-scale modeling to understand atmospheric change, vegetation responses, landscape water balance, and feedbacks that may affect the current rate of atmospheric CO2 change.

Research at the Landscape ScaleOver the past five years we have been tackling the landscape-scale dynamics of this problem: How do ecosystems comprised of different woody plant densities relative to grasses use water and photosynthetically capture CO2? What are the mechanisms associated with water use by individual plants, the impacts on intact vegetation stands, and the subsequent availability of water resources? Our focus has been on understanding how water and carbon processes are coupled because both of their exchanges are important for understanding water resources and potential feedbacks of ecosystems on rising CO2 in the atmosphere.

Our program measures water use and carbon sequestration (the uptake and storage of carbon) at six sites in riparian and upland settings covering a gradient of vegetation types in southeastern Arizona ranging from grass-dominated to shrub-dominated. We use micrometeorological techniques to quantify water and carbon fluxes between the biosphere and atmosphere at the ecosystem scale (100 m to 1 km), and plant physiological and hydrological techniques to understand how processes like respiration and evaporation from both plants and soils contribute to ecosystem-scale fluxes. Data

see Landscape, page 37


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R & DUNM Utton Center Develops Model Water CompactFrom the Utton Transboundary Resources Center

During the past half-century, American states have entered into some 26 interstate water allocation compacts, primarily in the West. As water conflicts increased, so did the realization among experts that most existing compacts were inadequate.

To help address that problem, the University of New Mexico’s Utton Transboundary Resources Center at the School of Law has developed a model water compact to help parties avoid costly litigation. In 2000, the project received congressional funding obtained by Sen. Pete Domenici.

The resulting product is now available as a document for use as a traditional interstate compact with states as signatory parties, or as a federal/interstate compact with the United States as a signatory party. The latter approach has been used in the compacts most recently approved by Congress.

“The beauty of the new model compact is that it can be adapted to different situations in the various river basins around the country,” said Utton Center Director Marilyn O’Leary.

For more than a year, O’Leary and staff analyzed existing compacts to identify and evaluate strengths and weaknesses in both theory and practice. The next step was to catalog the language in existing compacts as well as congressional consent legislation by topic to identify how critical issues were addressed historically.

O’Leary also assembled a 24-member advisory committee representing a range of professional experts and stakeholders in interstate water issues. Last March, the committee met in Santa Fe for a three-day workshop. Members evaluated and supplemented the principal issues identified by the project and offered further recommendations.

“This model river compact addresses the relevant and integrated scientific, economic, legal, and cultural factors that must be thoughtfully and thoroughly examined by any practicing water resource administrator,” said Ken Knox, Colorado’s chief deputy state engineer.

“The model compact properly takes into account the sovereign status of Indian tribes and their substantial water rights when they are present in a basin,” adds John Echohawk, director of the Native American Rights Fund.

Copies of the model compact can be downloaded from the UNM Utton Center website at uttoncenter.unm.edu/model_compacts.html

Beetles Help Curb Salt Cedar in TexasFrom the Texas Water Resources Institute

In the northern part of the Texas Panhandle and in West Texas, researchers from Texas A&M University and the USDA Agricultural Research Service (ARS) are successfully introducing a beetle to help control saltcedar (Tamarix), an invasive, water-thirsty plant.

Saltcedar was introduced to the western United States in the 1800s from central Asia as an ornamental tree and planted along riverbanks for erosion control. Without a natural predator, the tree soon out-competed native plants and has infested an estimated 500,000 acres of Texas streams and riverbanks. A single tree may withdraw three to four feet of water per year, depending on its density, age, and the depth to water. Saltcedar also increases soil salinity and wildfire risk, and crowds out native vegetation used by wildlife.

Aerially applied herbicides and controlled burning have been used with some success to reduce saltcedar, but its natural enemy, the saltcedar leaf beetle, or Diorhabda elongata, offers a low-cost, sustainable alternative. If established over time, a sufficient population of saltcedar beetles could shrink the saltcedar population. According to Jack DeLoach, an ARS

entomologist, saltcedar beetles feed only on saltcedar and will not harm native plants or trees.

DeLoach and other scientists have been conducting laboratory and field research to study beetle taxonomy and behavior, host range, reproduction and overwintering success, climate-matching, release methods, saltcedar growth modeling, and beetle dispersal. They are also measuring the impact of beetle feeding on plant survival and conducting remote sensing and vegetation and bird surveys.

After saltcedar beetles from China and Kazakhstan failed to survive in Texas, researchers imported a specific ecotype from Crete, Greece, which has overwintered successfully for three years. Field nursery sites were established for rearing the beetles in the Upper Colorado River (Texas) watershed, near Big Spring, which has more than 22,000 acres of saltcedar.

In addition to the Big Spring area, study sites have been introduced along the Pecos and Canadian rivers in West Texas. Researchers hope to work with Mexico to control saltcedar along the Rio Grande, where the largest concentration in the state lives.

The beetles kill saltcedar by defoliating the trees, causing them to use up their stored energy to grow new leaves, but eventually depleting that reserve. Researchers estimate that four to five years of repeated defoliation will be needed to kill small trees, although water use begins to fall before the trees die because of the reduced leaf canopy.

The goal is not to completely eradicate saltcedar, rather it is to reach a balance between the beetle and trees, with both in small populations. Hopefully, that balance will be achieved in about five years. The approach has already shown successful results in Nevada and Colorado.

Visit twri.tamu.edu/soil_water_grants/2005/ knutson_report.pdf.


Patent Coming for Long Beach Desal Technology Last fall, the Long Beach (California) Water Department (LBWD) announced that the U.S. Patent Office issued a Notice of Allowance for Patent Protection for a new seawater desalination process developed by LBWD engineers. The two-stage, relatively low-pressure nanofiltration process, dubbed the “Long Beach Method,” has been demonstrated to be 20 to 30 percent more energy efficient than reverse osmosis, the current state-of-the-art technology, and is the subject of more intense research and development activity at the nation’s largest, fully functional seawater desalination research and development facility in Long Beach. The patent is expected to be issued in early 2007.

The new technology was developed by former LBWD assistant general manager Diem Vuong, who retired recently but remains a consultant at the department’s seawater desalination facility. The process has been successfully tested at a 9,000-gallon-per-day (gpd) pilot-scale desalter. Now, with funding from the U.S. Bureau of Reclamation and the Los Angeles Department of Water and Power, it will be tested at a full-size, 300,000-gpd facility to see if the same energy savings can be achieved.

High operating costs, due primarily to high rates of power consumption, and

environmental issues related to open-ocean intake and discharge have rendered seawater desalination too costly and environmentally prohibitive in Long Beach to date. Energy consumption is extremely high due to the very high-pressure requirements of reverse osmosis membranes, thus the Long Beach Method has the potential to reduce energy costs.

To address environmental issues, LBWD is designing and constructing an under-ocean-floor intake and discharge demonstration system, the first of its kind in the world, in an attempt to demonstrate that viable, environmentally responsive intake and discharge systems can be developed along the California coast.

Visit www.lbwater.org/desalination/desalination.html.

NEMI Analytical Database Growing, Seeks New MethodsWhat is the most sensitive analytical method for your compound of interest? The most precise? The most cost-effective for your needs? The National Environmental Methods Index (NEMI) is a searchable online methods database that allows users to search and compare regulatory and nonregulatory field and analytical methods. Publicly released in 2002, NEMI now contains more than 800 method summaries, mostly for water analysis. Its purpose is to provide a mechanism to compare and contrast the performance and relative cost of analytical

and field methods for environmental monitoring. Water-related methods include radionuclide and non-radionuclide target analytes, as well as chemical preparation and biological methods. Summaries include all EPA wastewater and drinking water regulatory methods and most of the commonly used methods for nutrients and total maximum daily load measurements.

Recent additions include USGS field methods for measurement of pH, dissolved oxygen, conductance, redox, alkalinity, and temperature, as well as field protocols for biological population sampling and toxicity test information. Expected soon are USGS field protocols for the collection of depth- and width-integrated water column samples.

In the future, NEMI plans to add more field analytical and biological methods, methods for other media (air, soils, sediments, and wastes), and new methods for emerging contaminants of concern. In addition, an “expert system” user interface is planned. This software program will combine knowledge with data to provide targeted information for a user, as if the user were querying another human.

NEMI was developed under the direction of the Methods and Data Comparability Board, a partnership of water-quality experts from federal agencies, states, tribes, municipalities, industry, and private organizations. The board is chartered under the National Water Quality Monitoring Council, which in turn is chaired by the USGS and U.S. EPA.

New methods are sought for the database. These may include laboratory or field sampling methods in a variety of media/matrices such as air, water, soil, sediment, or tissues. Government, private, and public organizations, including commercial and volunteer monitoring sectors, may submit methods. Instructions and criteria for inclusion are available on the NEMI website.

Visit www.nemi.gov.

R & D (continued)


PEOPLETop Cal Environmental Advisor ResignsTerry Tamminen, a Democratic environmental advisor to California Gov. Arnold Schwartzenegger, resigned in August in order to campaign for the governor, saying he would not return after the election, reported the Los Angeles Times. Tamminen held a variety of positions in the Schwartzenegger administration, including environmental secretary, cabinet secretary, and advisor on energy and the environment. From this experience, he wrote the recently published book, Lives Per Gallon: The True Cost of Our Oil Addiction, published by Island Press.

According to the Times, Tamminen was close to the governor, well-positioned to advocate for solar energy, alternative fuels, and environmental protection. Environmentalists interviewed by the paper viewed his resignation as a loss, citing Tamminen’s ability to stand up to industries’ opposition to environmental regulation.

Tamminen told the Times that a major reason for his resignation was to better publicize the governor’s environmental record. In addition to volunteering with the campaign, he took a part-time position with AbTech Pacific, a distributor of stormwater filtration technologies, reported the paper.

Visit www.latimes.com.

Stuart Pyle MournedStuart Pyle, manager of the Kern County Water Agency for 17 years, died in August at age 81. From 1973 to 1990 he managed the agency, the second largest water contractor in the state, reported the Bakersfield Californian. During his tenure, he helped develop the state water project, oversaw construction of the Cross Valley Canal linking the California Aqueduct to Bakersfield, and led construction of the Henry C. Garnett Water Purification Plant in Bakersfield.

He was remembered as a well-regarded, fair, and highly respected manager by his agency’s board of directors, the paper said.

Visit www.bakersfield.com and www.kcwa.com.

Michael Brophy MournedMichael J. Brophy, an attorney with Ryley, Carlock & Applewhite in Phoenix since 1977, died in September from complications from cancer treatments. He was a prominent water attorney specializing in environmental and natural resources law, including interstate water banking arrangements. In 2005 and 2006 he was recognized as a leading lawyer in the environment and water rights areas of law by Chambers USA America’s Leading Lawyers for Business. He was a former chair of the Western States Water Council, during which time he conducted a Senate briefing on Indian water rights settlements. Brophy also made significant contributions to the advancement of water law and policy in Arizona.

Visit www.rclaw.com.

Myers New USGS LeaderIn September, Mark Myers of Alaska was confirmed by the U.S. Senate as the new director of the U.S. Geological Survey. His nomination in May by President Bush was noteworthy because Myers was neither already within the USGS nor in academia, as have been previous directors for the past half century.

A sedimentary and petroleum geologist specializing in the North Slope area, Myers spent much of his career as an exploration geologist working for various oil and gas companies, but early in his career and for the past decade, he worked for the Alaska Division of Oil and Gas. In October 2005, Myers resigned his position as director of the Division of Oil and Gas and state geologist in protest of the state’s concessions to oil and gas interests during negotiations to build a natural gas pipeline from the North Slope.

Myers’ nomination was met with mixed reviews. Nature.com reported that his background “has made many academic geologists nervous,” according to Charles Groat, the previous director of the USGS, now at the University of Texas. “The biggest question is, since he is so identified with oil and gas, what is his agenda?” Groat told Nature. Craig Schiffries, director of science policy for the National Center for Science and the Environment, expressed confidence that Myers would “stick to the science,” reported ES&T Online, citing Myers’ recent resignation as evidence of his unwillingness to bow to special interests.

Visit pubs.acs.org/journals/esthag/index_news.html and www.nature.com.

McConnell Named Researcher of the Year in NevadaLast summer, Joseph McConnell, a research professor at the Desert Research Institute, was awarded the Nevada System of Higher Education Regents’ Researcher of the Year Award in recognition of his landmark work in ice core chemistry, snow hydrology, paleoclimatology, and glaciology. McConnell’s research has resulted in numerous publications and considerable research funding, including a recent Fulbright fellowship for research in Argentina.

McConnell joined DRI in 1998 and has since developed a new method of ice core chemical analysis, resulting in a million-dollar, one-of-a-kind ice core laboratory. In this method, a continuous ice core melter is coupled to two inductively coupled plasma mass spectrometers and a traditional continuous flow analysis system to measure a large number of elements and chemical species simultaneously on ice cores at high depth resolution. This work has significantly broadened the utility of ice cores as archives of paleoclimate and industrial pollution.

Visit www.dri.edu.


Business Directoryare expected to decrease the ability of our mountain “water towers” to reliably deliver water in the quantities we have come to expect and when we most need it.

Society and Water in the SouthwestIt would be short-sighted to consider climate change in isolation from other aspects of the human-environment system. We need to consider the confluence of population growth, agricultural and recreational values, power generation needs, environmental laws, and other societal priorities. Our bountiful groundwater supplies built up over hundreds to thousands of years but, in the Southwest’s major urban areas, it has taken less than a century to deplete these supplies to levels that require active and vigilant management. Groundwater is renewable on relatively long time scales, and is considered by many water managers to serve as a back-up for fully renewable surface water supplies.

Increasing temperatures, due to expanding urban heat islands as well as regional climate trends, will increase power and water demands during the time of year when our water supplies are most vulnerable. The National Renewable Energy Laboratory estimates that, nationally, thermoelectric freshwater use for power generation roughly equals freshwater use for irrigation. For each kilowatt-hour of power consumed, Arizona and Nevada consume more than 7 gallons of water, Utah and California between 3 and 5 gallons, and Colorado and New Mexico about 1 gallon (Torcellini and others, 2003). Thus, increases in cooling system use as temperatures rise must be considered part of the effects of climate change and population growth on the water supply.

What Does it Mean for Me? According to the best science to date, we can reasonably expect changes in the timing of peak streamflow (earlier), rates of evapotranspiration (higher), and the duration and severity of future droughts (longer, more severe). We can also expect water and energy demand to increase as a result of increased temperatures, longer heat waves, and urban warming. The combination of these changes, as well as others that are less predictable, will require resource management that is flexible and that can incorporate the latest scientific knowledge. From the imperfect but valuable body of information that bridges observed and projected climate changes, we can develop plausible scenarios to guide management options.

Contact Gregg Garfin at [email protected].

ReferenceTorcellini, P., N. Long, and R. Judkoff, 2003. Consumptive Water Use for

U.S. Power Production. National Renewable Energy Laboratory report, NREL/CP-550-35190, www.nrel.gov/docs/fy04osti/35190.pdf.

Effects, continued from page 17

john j ward, rg groundwater consultant

- water supply - water rights - peer review - litigation support - expert witness - due diligence

Tucson AZ

phone: (520) 296-8627cell: (520) 490-2435

email: [email protected]: www.wardgroundwater.com


to 1895-2005) in the Colorado Basin. The subsequent quarter century (2035-2060) is projected to undergo a similar incremental warming: an average 2.8°C over the Upper Colorado. This drives the Palmer Index down to drought severity rarely witnessed during the 20th century.

Past Peak WaterWhat are the implications of intensified aridity for Colorado River flow? Downscaling the simulated PDSI to Lees Ferry flow yields an average rate of 10 maf for the next 25 years. As drought conditions further intensify due to heat, Colorado River flows would decline further (see charts below), averaging 7 maf during 2035-2060, values equivalent to the observed lowest flow at our recent drought’s nadir.

Are such low flows realistic on a year-by-year sustained level? First, virtually all simulations point to sufficient drought to reduce flow below current consumptive uses on the river within 20 years, although the range of model outcomes indicates that we don’t know precisely how low the flow will be. Second, whereas the 21st century climate change signal is one of low Colorado River flow, the superimposed natural variability in precipitation is still capable of producing “normal” flow (by 20th century standards) for a year or two within an otherwise drought epoch. Finally, it is

unclear whether the historical Lees Ferry flow-PDSI relation used in this study is strictly applicable to the substantial change in climate that is projected.

Nonetheless, a robust physical relation underpins the projected reduction in Colorado River flow. Evapotranspiration exceeds precipitation throughout the basin, implying less runoff as dictated by water balance requirements. Also, the Lees Ferry flow estimated from the climate simulations for 1990-2005 is 13 maf, an already substantial decline from higher simulated flows in the early 20th century. This change is remarkably consistent with observations and suggests an emerging warming effect on streamflow.

Relative to the 1990-2005 mean flow of 13 maf, the 42-run average predicts a 25 percent decline in streamflow during 2006-2030, and a 45 percent decline during 2035-2060. This scenario is consistent with several independent estimates using different approaches. Revelle and Waggoner (1983) used empirical methods to predict a 29 percent reduction in Lees Ferry flow under a scenario of 2°C warming. Christensen and others (2004) used a sophisticated hydrology model to predict an 18 percent reduction in Colorado River streamflow by 2050 under a change scenario derived from a climate model that is now recognized to be on the low range of climate change sensitivity. Milly and others (2005) diagnosed annual runoff in

12 different AR4 models and discovered a near 20 percent decline in runoff for the Colorado River headwaters by 2050.

Our study reveals that a sustained change in moisture conditions is unfolding within the broad range of natural variations. The Southwest is likely past the peak water experienced in the 20th century preceding the signing of the 1922 Colorado Compact: a decline in Lees Ferry flow will reduce water availability below current consumptive demands within a mere 20 years. These projections further expose the risky reliance by Colorado River water users upon the Compact as a guarantee that streamflows will always materialize to match legislated requirements.

Contact Martin Hoerling at [email protected].

ReferencesChristensen, N.S., A.W. Wood, N. Voisin, D.P.

Lettenmeier, and R.N. Palmer, 2004. The effects of climate change on the hydrology and water resources of the Colorado River Basin, Climatic Change 62(1): 337-363.

IPCC, 2001. Climate Change, 2001: The Scientific Basis, ed. by J.T. Houghton, Y. Ding, D.J. Griggs, M. Noguer, P.J. van der Linden, and D. Xiaosu, Cambridge University Press, 881 pp.

Milly, P.C.D., K.A. Dunne, and A.V. Vecchia, 2005. Global patterns of trends in streamflow and water availability in a changing climate, Nature, 438: 347-350.

Palmer, W.C., 1965. Meteorological Drought, U.S. Dept. of Commerce, Weather Bureau Research Paper No. 45, Washington, D.C.

Revelle, R., and P. Waggoner, 1983. Effects of a carbon dioxide-induced climatic change on water supplies in the western United States, in Changing Climate, by the Carbon Dioxide Assessment Committee, pp. 419-432, National Academy Report 8211, Washington, D.C.

Past Peak, continued from page 19

The 1895-2050 Lees Ferry annual streamflow (left) was derived from the AR4 simulations of PDSI (middle) using the downscaling formula that relates observed Lees Ferry flow to observed PDSI during the 20th century. The dark red curve denotes the 42-run average, and the cloud describes the 10 to 90 percent range of individual simulations. The right panel summarizes the probability distribution function of PDSI averaged over the Upper Colorado Drainage Basin for individual years of observations 1895-2005 (black), for the 42 models for 1895-2005 (green), and for the 42-model projections of the average PDSI during 2006-2030 (orange) and 2035-2060 (red). Note that the models produce a realistic range of PDSI drought events during the 20th century, and for the future they produce surface moisture conditions that denote progressive aridification and severe drought conditions.

Lees Ferry Flow

20th century average

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Upper Colorado PDSI

Observed: 1896 — 2005

AR4 20th C

AR4 21st: 2006 — 2030

AR4 21st: 2035 — 2060

1900

26

24

22

20

18

16

14

12

10

8

6

4

12

8

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-121920 1940 1960 1980

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2000 2020 2040 1900 1920 1940 1960 1980 2000 2020 2040


Streamflow, continued from page 27

What To Do?Trends that have natural origins may well reverse themselves, but if they are driven by manmade influences on the climate system, streamflow timing may continue to change. If present trends continue, the natural reservoirs provided by western snowfields will become progressively less useful for water-resources management, flood risks may change in unpredictable ways, and many mountain landscapes will experience increasingly severe summer-drought conditions.

Given the potential for large impacts of climate change on water resources, water management policies that promote flexibility and resilience will be needed to accommodate potential warming impacts, although they remain uncertain. Equally important, continued and enhanced streamflow monitoring and analysis of western snow-fed rivers will be needed to determine the precise natural and human-induced causes, and the likely future, of these western streamflow-timing trends.

ReferencesCayan, D.R., S. Kammerdiener, M.D. Dettinger, J.M.

Caprio, and D.H. Peterson, 2001, Changes in the onset of spring in the western United States: Bull. Amer. Meteor. Soc., 82: 399-415.

Cayan, D.R., I. Stewart, and N. Knowles, 2005. Recent changes towards earlier springs: Early signs of climate warming in western North America? Watershed Management Council Networker, Spring 2005. tenaya.ucsd.edu/~dettinge/Networker_Spring2005.pdf

Dettinger, M.D., and D.R. Cayan, 1995. Large-scale atmospheric forcing of recent trends toward early snowmelt in California, J. Clim., 8: 606-623.

Florsheim, J., and M. Dettinger, 2005. Influence of 19th and 20th century landscape modifications on likely geomorphic responses to climate change in San Francisco Bay-Delta and watershed. Watershed Management Council Networker, Spring 2005. tenaya.ucsd.edu/~dettinge/Networker_Spring2005.pdf

Roos, M., 1991. A trend of decreasing snowmelt runoff in northern California, Proc. 59th Western Snow Conference, Juneau, AK, pp. 29-36.

Stewart, I., D.R. Cayan, and M.D. Dettinger, 2004. Changes in snowmelt runoff timing in western North America under a ‘Business as Usual’ climate change scenario, Climatic Change, 62: 217-232.

U.S. Dept. of the Interior, Changes in streamflow timing in the western United States in recent decades, USGS Fact Sheet 2005-3018, pubs.usgs.gov/fs/2005/3018/.

streamflow with reconstructed streamflow to recreate a likely temperature and precipitation record to represent the paleoclimate record. Our goal was to develop a new reconstruction of streamflows that was similar to the tree-ring-derived reconstruction in terms of: 1) duration, 2) average streamflow, and 3) overall frequency of extreme flows.

Our approach was to select several years from the observed record in which the annual streamflow closely matched that of a single year in a 400-year reconstructed streamflow record developed by Woodhouse. From this subset of years, we used a random selection process, placing the greatest weight on the closest match, but allowing for some variability, to determine the “selected” year from the observed record that would serve as the analog for the particular year from the paleo record. The process was repeated for each year of the paleo record.

The result is an ensemble of data from the observed record that approximates the volume of total annual streamflow and variability of the paleo record, but that contains temperature and precipitation data which can be used to approximately recreate paleoclimate conditions.

The monthly temperature and precipitation values will next be used as input parameters for the Snowmelt-Runoff (SRM; Martinec et al., 1994) and WATBAL (Rosenzweig et al., 2004) models to produce new “modeled” streamflows for Boulder Creek. SRM simulates and forecasts daily streamflow in mountainous basins where snowmelt is a major runoff component, and WATBAL is an integrated water balance model developed for climate change impact assessment of river basin runoff. Changes in temperature and precipitation from climate models for the central Rocky Mountains will be combined with the new paleoclimate temperature and precipitation data set. This will produce estimates of the conditions that would be experienced under a warmer climate with changes in

average precipitation, but also one with more variability than in the recent record.

This approach will allow water managers to use the paleoclimate record and climate change models jointly to evaluate the risks from both climate change and climate variability together, providing an improved tool for water resources planning. In other words, water managers can examine what would happen if past droughts happen again, but this time under warmer conditions consistent with climate change.

ReferencesMartinec, J., A. Rango, and R. Roberts, 1994.

The Snowmelt Runoff Model Users Manual, Geographica Bernensia P35, ed. by M. F. Baumgartner, University of Berne. Switzerland.

Mote, P.W., A.F. Hamlett, P.W. Clark, and D.P. Lettenmaier, 2005. Declining mountain snowpack in western North America, Bulletin of the American Meteorological Society, 86: 39-49.

Rosenzweig, C., K.M. Strzepek, D.M. Major, A. Iglesias, D.N. Yates, A. McCluskey, and D. Hillel, 2004. Water resources for agriculture in a changing climate: International case studies. Global Environmental Change, 14: 345-360.

Severe Sustained Drought: Managing the Colorado River System in Times of Water Shortage, special issue of Water Resources Bulletin, 31(5), October 1995. Available at www.hydrosphere.com/publications/ssd/ssd.htm

Tool Kit, continued from page 25



from the 2003 growing season at our riparian sites highlight the coupling of carbon and water cycles on the landscape. At these sites, the density of woody plants compared to grasses strongly controlled water and carbon exchanges (see figure, right). The woodland site had the highest rates of ET throughout the growing season, whereas total ET from the shrubland and grassland sites were similar. By solving a simple water budget at each site, we calculated the amount of ET derived from groundwater, and found it varied by site according to the abundance of woody plants. The woodland used 473 mm of groundwater, while the shrubland used 265 mm and the grassland used 227 mm over the season. However, the net accumulation of carbon in each ecosystem showed a different pattern (see figure). While the woodland exhibited the highest rates of carbon dioxide exchange with the atmosphere, the shrubland showed equivalent carbon storage over the season to the woodland. In contrast, grassland had the lowest rates of carbon exchange and sequestered less atmospheric carbon over the season.

The discrepancy between the ET and carbon accumulation responses at our sites occurs in part due to how the different components of carbon exchange, ecosystem photosynthesis (influx of carbon from the atmosphere), and ecosystem respiration (efflux of carbon to the atmosphere) relate to surface water inputs. As woody plants become more abundant on the landscape, ecosystem photosynthesis becomes more coupled to groundwater rather than surface water. The loss of water to the atmosphere and sequestration of carbon are both controlled by vegetation such that the two processes are negatively related: systems with greater water loss through ET also sequester or accumulate more CO2 from the atmosphere. As such, land managers likely will need to consider the potential trade-off between these two exchanges at the landscape scale when they make decisions on vegetation management.

Contact Travis Huxman at [email protected] and Russell Scott at [email protected].

Average weekly net ecosystem exchange (NEE) of CO2 (top), average weekly evapotranspiration (middle), and weekly total precipitation (bottom) for 2003. Solid vertical lines mark last spring and first fall freeze; dashed vertical lines bound the summer monsoon. Figure modified from Scott, R.L., T.E. Huxman, D.G. Williams, and D.C. Goodrich, 2006. Ecohydrological impacts of woody plant encroachment: seasonal patterns of water and carbon dioxide exchange within a semiarid riparian environment, Global Change Biology, 12, pp. 311-324, Blackwell Publishers.

Landscape, continued from page 29


AZ Water Rights Auction a BustIn November, the town of Prescott Valley, Arizona, 85 miles north of Phoenix, held an auction to sell 2,724 acre-feet annually of treated effluent that could be used to support real estate and economic development. The auction was the first of its kind and size in the

United States, according to a press release from WestWater Research LLC.

Prescott Valley hoped to generate more than $50 million in revenue, according to Clay Landry of WestWater Research, the town’s water-marketing consultant. The auction was publicized nationally for six months before the

event, and the consultant was paid $100,000 to plan it, reported the [Yavapai County] Daily Courier.

Alas, the auction drew only one qualified bidder, an investing firm from Nebraska, said the Courier. After no offers were made for the entire quantity, the town established a minimum price of $28,000 per acre-foot. According to the newspaper, several other offers were made below the minimum.

What’s next? Prescott Valley needs around $75 million to pay for its portion of a planned 4,000 acre-foot-per-year water supply project, for which the bills may start arriving soon. Options outlined by the Courier include issuing bonds, selling the treated water as an asset, or rescheduling the auction. The latter option appears likely, given that other parties expressed some interest in the water.

Prescott Valley has been growing rapidly, with its current 33,000 residents expected to increase to more than 52,000 residents by 2025. In 2005, a record 1,100 new homes sold in Prescott Valley, driving the urgency for the new water supply. However, sales in the first 10 months of 2006 fell to a seven-year low of around 640 homes, according to the Courier—perhaps diminishing that urgency.

Visit www.waterexchange.com and prescottdailycourier.com.

TestAmerica Acquires Severn TrentIn September, TestAmerica announced that Severn Trent Laboratories (STL) was acquired by an H.I.G. Capital affiliate, a private investment firm that owns TestAmerica. With the purchase, the two environmental testing companies will be combined. Prior to the merger, STL had 31 laboratories nationwide and TestAmerica had 73, including the recently acquired Del Mar Analytical Laboratories in California and Arizona.

Visit www.testamerica.com.

COMPANY LINE

Effects of urban development on stream ecosystems along the Front Range of the Rocky Mountains, Colorado and Wyoming, by L.A. Sprague, R.E. Zuellig, and J.A. Dupree.http://pubs.usgs.gov/fs/2006/3083/

Application of a stream-aquifer model to Monument Creek for development of a method to estimate transit losses for reusable water, El Paso County, Colorado, by Gerhard Kuhn and L Rick Arnold. http://pubs.usgs.gov/sir/2006/5184/

Questa baseline and pre-mining ground-water quality investigation. 21. Hydrology and water balance of the Red River Basin, New Mexico 1930-2004, by C.A. Naus, D.P. McAda, and N.C. Myers.http://pubs.usgs.gov/sir/2006/5040/

Characterization of dissolved solids in water resources of agricultural lands near Manila, Utah, 2004-05, by S.J. Gerner, L.E. Spangler, B.A. Kimball, and D.L. Naftz. http://pubs.usgs.gov/sir/2006/5211/


Educating Tomorrow’s Water Leaders Sue McClurg – Water Education Foundation

Established by the Water Education Foundation (WEF) in 1997, the William R. Gianelli Water Leaders Class is a year-long program that teaches young water professionals about current water issues, divergent viewpoints, and potential water resource solutions. In the past decade, 148 California, Arizona, and Nevada professionals from the engineering, water utility, legal, environmental, local government, legislative, and other water resource communities have completed the program.

Fifteen to 18 people are selected for each class after a competitive application process. Through WEF-sponsored water tours and briefings, class members work collaboratively on a report about a specific water-related topic. Previous classes have examined a variety of topics, from water conservation to the Endangered Species Act to flood management.

Participants learn much about these issues from their mentors, who are high-level water professionals. Each student is purposely paired with a mentor from an opposite point of view, for example, someone from an urban water agency would be assigned a mentor from the agricultural or environmental sector.

The class convenes at a January orientation where speakers from various sectors provide background information about current water issues, with a special focus on the research topic. Participants are expected to spend at least one day “shadowing” their mentor. Class members then work to prepare a final list of 20 detailed questions about the particular research topic and then interview their mentors in person, by telephone, or by email. Often, the professional relationship extends beyond the actual class assignment. Additional time commitments include attending WEF’s 1-1/2 day executive briefing, two three-day water tours, and a summer meeting.

The mentor system, said Foundation Executive Director Rita Schmidt Sudman, not only helps preserve the institutional memory of historic water events but also helps students—and mentors—learn about a different viewpoint. “The fact that important people in the water and environmental world, from state and federal agency heads to congressional leaders, take time to meet and mentor these water leaders creates a memorable experience for these young people,” Sudman said. “And the mentors seem to enjoy the responsibility and interaction.”

Sudman and former Foundation Board Member Jean Auer were the driving forces behind the creation of the program. Auer, the first woman appointed to the California State Water Resources Control Board, served as class adviser from 1997 until her death in 2005.

Class members are selected based on their commitment to understanding water issues; interest in seeking leadership roles on public boards and commissions; commitment to the community through volunteer activities; and potential or existing opportunities for advancement within their own organizations.

Funding for the class is provided by grants and a $1,500 tuition fee, with some scholarships awarded. In 2002 former WEF Board President Bill Gianelli presented the foundation with a $100,000 gift for the Water Leaders Program as an investment in the future. Gianelli served as assistant secretary for the Army in charge of the Corps of Engineers from 1981 to 1984 and Director of the California Department of Water Resources from 1967 to 1973.

Graduates give the program high marks: 90 percent say their ongoing relationship with class members has helped them in their own careers while 100 percent say they would recommend the class to a colleague. In 2004, an alumni organization was established to promote continued networking among graduates and fundraising to support the program. The organization raises funds through a silent auction conducted each year at the executive briefing.

The Water Leaders Class runs on a calendar year. Contact Jean Nordmann, [email protected], or 916-444-6240, for an application for the 2008 class. Visit the Water Education Foundation at www.watereducation.org

EDUCATION


An Inconvenient TruthSouthwest Hydrology set out to learn what climate scientists are saying about former Vice President Al Gore’s movie, “An Inconvenient Truth,” released last summer. The movie, adapted from his book of the same name, follows Gore’s crusade to educate the public about what he views as the major environmental crisis our planet is headed toward if we don’t collectively and immediately act to avert it. Did Gore get the science right?

The movie’s supporters, including a large contingent at realclimate.org, a blog site about “climate science from climate scientists,” praise its effectiveness in making science interesting to the general public, to the extent that the movie was a hit and has raised the public’s literacy level on climate issues. They commend Gore’s clear, (mostly) accurate, and not overly alarmist presentation of what is likely to occur if human-induced greenhouse gas emissions continue unabated.

Spiegel Online investigated the integrity of Gore’s science and found that the strongest criticism has come from individuals who receive funding from coal and oil industries, such as Robert C. Balling Jr., professor of climatology at Arizona State University, and organizations such as the Competitive Enterprise Institute. CEI

calls the movie “one-sided, misleading, exaggerated, speculative, wrong” and lists 25 “truths” that it believes Gore left out. Critics generally focus on specific points in the movie, some of which even the supporters concede could be misleading. Examples include:

The effect of carbon dioxide on temperature: CEI says a graph showing CO2 concentrations correlated to temperature over time is misleading because the relationship is not linear and projecting the future temperature increases based on predicted CO2 increases is incorrect. Supporters agree that the graph could be misinterpreted, although they say Gore’s linkage of temperature and CO2 in ice cores is valid.

Melting snowfields and glaciers: In a movie review published by TCSDaily.com, Balling says the snows of Kilimanjaro, cited in the movie as evidence of global warming, are melting because of a local shift to drier conditions that began about a century ago. CEI argues that glaciers have been receding worldwide for more than a century. Scientists at realclimate.org counter that the snowpack retreat on Kilimanjaro cannot be fully accounted for by changes in atmospheric moisture. Furthermore, focusing on one specific example ignores the point that worldwide, glaciers are retreating.

Katrina: Both Balling and CEI cite studies finding no correlation between global temperature and an increase in the strength or frequency of hurricane-force storms. Realclimate.org says that Gore used scenes of Hurricane Katrina destruction to illustrate that society is vulnerable to weather extremes, but that he stopped short of making a strong climate change-hurricane connection, as the science remains uncertain.

Effect of the Clean Air Act: All scientists agree that Gore incorrectly claims that the effect of the Clean Air Act can be seen in changes of aerosol concentrations in Antarctic ice cores in just two years.

Invasive Species: Gore suggests, but does not directly state, that climate change alone is the cause for invasive species. Scientists agree that invasive species are opportunistic and capable of surviving in a range of environments, thus they may thrive where other species cannot, but other factors also must come into play, including their introduction to an area.

In spite of these points, the consensus seems to be that Gore basically did get the science right. A few of his visual data presentations are potentially misleading, but he chose his words carefully and made few technical mistakes.

Visit www.realclimate.org, www.cei.org, tcsdaily.com, and www.spiegel.de/international/.

MOVIE REVIEW

�0 • January/February 2007 • Southwest Hydrology

HYDRUSJohn E. McCray – Colorado School of Mines. Software Review courtesy of International Ground Water Modeling Center and Colorado School of Mines.

The HYDRUS-2D/3D software package is a major upgrade and extension of the HYDRUS-2D/MESHGEN-2D software package originally developed and released by the U.S. Salinity Laboratory, PC-Progress and the International Ground Water Modeling Center. The new version, released under the name HYDRUS, is a Microsoft Windows-based modeling environment for analysis of water flow, solute, and heat transport in variably saturated porous media.

For flow, the code solves the mixed form of the Richards’ equation, with many functions for simulating hydraulic conductivity versus water content (or pressure head) relationships, including hysteresis. It allows root water uptake with compensation and spatial root distribution functions, and includes new soil hydraulic property models. The new code allows for dynamic, system-dependent boundary conditions such as switching among pressure heads, seepage face, zero flux, or atmospheric boundaries, depending on the position of the water level.

For solute transport, the code solves the advection-dispersion equation, but with many processes not usually included in unsaturated zone codes. For example, in addition to the typical linear partitioning between soil, water, and gas phases, the code also simulates the following processes: non-linear and non-equilibrium partitioning between phases; diffusion in the gas phase; zero- and first-order degradation kinetics, including decay chains (such as for nitrates and radionuclides); advective flow in a dual-porosity system allowing for preferential flow in fractures or macropores while storing water and dissolved chemicals in the matrix; transport of viruses, colloids, and bacteria using an attachment/detachment model; filtration theory; blocking functions; and flowing

particles in two-dimensional applications. HYDRUS also includes a new constructed wetland module, only in 2-D.

HYDRUS still allows optimization in 1-D and 2-D; unfortunately, it is not provided for 3-D applications. Another useful new feature is better print management, allowing the user to print at regular time intervals or after a constant number of time steps.

The GUI is much improved with many new user-friendly functions, such as drag-and-drop, context-sensitive pop-up menus after clicking on objects, selection and editing of multiple objects in the same dialog window, and allowing multiple projects and views to be opened at the same time in the HYDRUS main window. One of the best new features is that time-varying and cumulative fluxes can be calculated and displayed across internal meshlines.

The only negatives associated with the program are that the user’s guide could be more complete. Not all features are explained well enough for a modeler without previous HYDRUS experience to easily follow. However, the online discussion forum is very helpful; it can be found at www.pc-progress.cz/_Forum/default.asp.

Pricing varies depending on the level purchased. Single-computer licenses are $1,500 for HYDRUS that can handle applications for simple (hexahedral) geometries, and $1,800 for HYDRUS

standard for 3-D geometries comprising flexible 2-D geometries and layers for the third dimension. A professional version that will allow application of general, flexible 3-D geometries is expected in summer 2007.

The original, public-domain version of HYDRUS-1D is included in the HYDRUS package and may still be downloaded for free from the IGWMC web site at www.mines.edu/igwmc/software/igwmcsoft/hydrus1d.htm. HYDRUS may be purchased by visiting typhoon.mines.edu/software/igwmcsoft/hydrus3d.htm.

SOFTWARE REVIEW

Excellent

Rating System:

EaseofUse:

GUI:

Output/Plotting:

Documentation:

Speed:

OVERALLRATING:

International Ground Water Modeling Center

Colorado School of Mines

Poor

Application Vadose zone flow and transport

Best Features New GUI

Worst Feature No optimization in 3D

Review of HYDRUS-2D/3D

January/February 2007 • Southwest Hydrology • �1

T H E C A L E N D A R

JANUARY2007

FEBRUARY2007

MAY2007

January 4- 5 CLE International. California Wetlands: 13th Annual Conference. Sacramento, CA. www.cle.com/upcoming/PDFs/SACWET07.pdf

January 11-12 Multi-State Salinity Coalition. 200�/2007 National Desalination and Salinity Management Summit. San Diego, CA. multi-statesalinitycoalition.com/news.asp

January 23-26 Texas Ground Water Association. TGWA Annual Convention and Trade Show. Waco, TX. www.tgwa.org/meetings/index.html

January 29-30 CLE International. Nevada Water Law. Reno, NV. www.cle.com/dev/product_info.php?products_id=765

February 1- 2 CLE International. Law of the Rio Grande. Santa Fe, NM. www.cle.com/upcoming/PDFs/SFERIO07.pdf

February 8-10 Water Well and Ground Water Associations of AZ, CO, NV, NM, and UT. Mountain States Ground Water Expo 2007. Laughlin, NV. www.mountainstatesgroundwater.com

February 18-21 Geo-Institute of ASCE. Geo-Denver 2007: New Peaks in Geotechnics (Conference). Denver, CO. content.asce.org/conferences/geodenver07/welcome.html

February 20-22 Nevada Water Resources Association. NWRA Annual Conference. Reno, NV. www.nvwra.org/events.asp

February 27-March 1 Midwest Geosciences Group. Advanced Aquifer Testing Techniques Featuring AQTESOLV: New Concepts, Field Methods, and Data Analysis Procedures. San Diego, CA. www.midwestgeo.com/sandiego2007.htm

February 28-March 1 New Mexico State University. Symposium on River Terrace and Floodplain Hydrology. Las Cruces, NM. spectre.nmsu.edu:16080/water/welcome.html

March 2- 3 American Water Works Association. AWWA 2007 Research Symposium. Reno, NV. www.awwa.org/conferences/research/

March 8- 9 CLE International. Colorado Water Law. Denver, CO. www.cle.com/dev/product_info.php?products_id=783

March 11-13 American Society of Agricultural and Biological Engineers. �th Conference on Watershed Management to Meet Water Quality and TMDLs Issues. San Antonio, TX. www.asabe.org/meetings/tmdl2007/

March 13-15 National Ground Water Association. Environmental Geochemistry of Metals: Investigation and Remediation (short course). Las Vegas, NV. www.ngwa.org/pdf/e/course/576mar07.pdf

March 13-16 Nevada Rural Water Association. NvRWA Annual Training and Technical Conference. Reno, NV. www.nvrwa.org

March 19-22 Association for Environmental Health and Sciences. 17th Annual AEHS Meeting and West Coast Conference on Soils, Sediments, and Water. San Diego, CA. www.aehs.com/conferences/westcoast/

March 19-23 New Mexico Rural Water Association. 2007 Annual Conference. Albuquerque, NM. www.nmrwa.org/2007conference.php

March 20-23 NWS Climate Services Division and University of Washington. Climate Prediction Applications Science Workshop. Seattle, WA. www.cses.washington.edu/cig/outreach/workshopfiles/cpasw07/

April 1- 5 Environmental and Engineering Geophysical Society. SAGEEP 20th Annual Meeting: Geophysical Investigation and Problem Solving for the Next Generation. Denver, CO. www.eegs.org/sageep/

April 12-13 CLE International. California Water Law. San Francisco, CA. www.cle.com

April 22-25 American Institute of Hydrology. Integrated Watershed Management: Partnerships in Science, Management, and Planning (Annual Meeting and International Conference). Reno, NV. www.aihydro.org/conference.htm

April 23-24 CLE International. Texas Water Law (conference). Houston, TX. www.cle.com

April 29-May 3 National Ground Water Association. 2007 Ground Water Summit. Albuquerque, NM. www.ngwa.org

May 8-11 National Ground Water Association. The New MODFLOW Course. Las Vegas, NV. www.ngwa.org/pdf/e/course/258may07.pdf

May 8-11 Association of California Water Agencies. 2007 Spring Conference and Exhibition. Sacramento, CA. www.acwa.com/events/

May 10-11 CLE International. Colorado River SuperConference. Las Vegas, NV. www.cle.com

MARCH2007

APRIL2007

�2 • January/February 2007 • Southwest Hydrology

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