Part III Case Studies in Drought and Water Management: The Role of Science and Technology DK2949_book.fm Page 247 Friday, February 11, 2005 11:25 AM Copyright 2005 by Taylor & Francis Group 249 10 The Hardest Working River: Drought and Critical Water Problems in the Colorado River Basin ROGER S. PULWARTY, KATHERINE L. JACOBS, AND RANDALL M. DOLE CONTENTS I. Introduction: History of Colorado River Basin Development 250 II. Social and Economic Contexts 254 A. Water Quantity 258 B. Water Quality 259 III. The Climatic Context 261 IV. Four Climate-Sensitive Decision Environments 264 A. International: The Border Region 264 B. Arizona and California: Interstate Issues in the Lower Basin 267 1. The Quantification Settlement Agreement (QSA) 268 C. Native American Water Rights 269 DK2949_book.fm Page 249 Friday, February 11, 2005 11:25 AM Copyright 2005 by Taylor & Francis Group 250 Pulwarty et al. D. Conjunctive Use and Management: Groundwater and Surface Water in Arizona 270 V. Opportunities for Technological Interventions and Climate Science Applications 274 A. Opportunities for Application of Climatic Information 275 VI. Present Conditions on the Colorado: Situation “Normal” = Situation “Critical” 276 VII. Conclusion 277 References 280 You are piling up a heritage of conflict and litigation over water rights for there is not sufficient water to supply the land … John Wesley Powell, 1893 International Irrigation Conference, Los Angeles cited in Stegner, 1954, p. 343 I. INTRODUCTION: HISTORY OF COLORADO RIVER BASIN DEVELOPMENT The Colorado River flows 2300 km (about 1400 mi) from the high mountain regions of Colorado through seven basin states to the Sea of Cortez in Mexico (Figure 1). The river supplies much of the water needs of seven U.S. states, two Mexican states, and 34 Native American tribes. These represent a population of 25 million inhabitants, with a projection of 38 million by the year 2020. Approximately 2% of the basin is in Mexico. The Colorado does not discharge a large volume of water. Because of the scale of impoundments and withdrawals relative to its flow, the Colorado has been called the most legislated and managed river in the world. It has also been called the most “cussed” and “discussed” river in the United States. About 86% of the Colorado’s annual runoff originates within only 15% of the area, in the high mountains of Colorado and the Wind River Range in Wyoming. In the semiarid South- west, even relatively small changes in precipitation can have DK2949_book.fm Page 250 Friday, February 11, 2005 11:25 AM Copyright 2005 by Taylor & Francis Group The Hardest Working River 251 large impacts on water supplies. The coefficient of variation for the Colorado is about 33%. Climate and weather events form a variable background on which water agreements and conflicts are played out. Indeed, Powell’s comment above, as dire as it might seem, was not made in the context of potentially large swings in the climate system. The specter of long-term climate variations overlays a series of other issues, including growth in munic- ipal and industrial water demands, groundwater depletion, unmet ecosystem needs, and water quality requirements. Dec- adal-scale climatic factors influencing present water alloca- Figure 1 The Colorado River basin. (From the U.S. Department of the Interior, Bureau of Reclamation.) WA WY MT NV OR ID UT CA AZ NM TX MEXICO MEXICO ND SD NE KSCO OK WYOMING Green Green River River River River River River River Virgin River River River River Ya m p a Colorado Gunnison COLORADO Colorado UTAH GLEN CANYON DAM Paria River LAKE MEAD HOOVER DAM CALIFORNIA Gulf of California Pacific Ocean Colorado Gila River Gila Salt NEW MEXICO Little Lower Colorado River Basin LEE FERRY LAKE POWELL San Juan Upper Colorado River Basin 0 SCALE OF MILES 50 100 GRAND CANYON AIRZONA NEVADA DK2949_book.fm Page 251 Friday, February 11, 2005 11:25 AM Copyright 2005 by Taylor & Francis Group 252 Pulwarty et al. tions, discussed in greater detail elsewhere (Dracup, 1977; Stockton and Boggess, 1979), are of increasing significance in the management of the Colorado. In addition, it is likely that climatic changes may already be affecting the snowpack and runoff conditions in the Colorado watershed. This introduces a new set of forcings on regional climate factors that affect water supply. As has been well documented, the most important man- agement agreement (the Colorado River Compact of 1922) was based on overestimation of the reliable average annual supply of water due to a short observational record. Briefly, the period 1905–25 was the wettest such period in 400 years of record, with 16.4 million acre-feet (maf 1 ) reconstructed annual average flow at Lees Ferry. The 1922 compact signa- tories used this average number as the base minimum for fixed allocation between upper and lower basins. As a nod to interannual variability in water supply, the signatories assumed that flow would average out over 10 years and made the downstream requirement 75 maf over the said 10-year period. Colorado River streamflow, however, exhibits strong decadal and longer variations (Figure 2). Since the signing of the compact, the reliable estimated annual virgin flow has been about 14.3 maf, with a historic low flow of 5.6 maf in 1934. Emphases on water demand management, meeting obli- gations to Native American tribes, maintaining water quality, and environmental concerns have also altered the traditional roles of federal, state, and local agencies. The impacts of recent events such as the continuing regional-scale droughts since 1999, including the extreme drought of 2002, and recent enforcements restricting California to its compact allotment are only just beginning to be understood in terms of system criticality and requirements for noncrisis or proactive mitiga- tion of drought impacts. 1 1 maf = 1.24 million liters (325, 851 million gallons). Million acre-feet (maf) is used as the unit of water volume throughout this chapter. All entities on the Colorado River use maf as the unit of measure. DK2949_book.fm Page 252 Friday, February 11, 2005 11:25 AM Copyright 2005 by Taylor & Francis Group The Hardest Working River 253 This chapter uses climate-sensitive decision environ- ments along the Colorado River to illustrate the breadth and complexity of the water management issues and the role of climate in these contexts. The four examples are in: (1) the border region: international issues; (2) Arizona and Califor- nia: interstate issues in the Lower Basin; (3) Native American water rights; and (4) conjunctive use and management: groundwater and surface water in Arizona. Recent drought impacts on the Colorado River reservoirs have raised significant concern about the reliability of deliv- eries in the event of a decadal or multi-decadal drought. Until recently, the expectation of Colorado River managers was that significant shortages in the Lower Basin would not occur until after 2030. With reservoir levels at historic lows, newspaper Figure 2 Decadal-scale variability of Colorado River streamflow at Lees Ferry, 1896–2003. Smoothed using a 9-year moving average. (Data from the U.S. Department of the Interior, Bureau of Recla- mation.) Annual Colorado River Flow at Lees Ferry, Arizona Mean annual flow = 14.8 million acre-feet 5 4 3 2 1 0 −1 −2 −3 −4 −5 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 Year Departure in million acre-feet DK2949_book.fm Page 253 Friday, February 11, 2005 11:25 AM Copyright 2005 by Taylor & Francis Group 254 Pulwarty et al. headlines and politicians are focused directly on the drought/water supply issue. Generally, focusing events like this expose critically vulnerable conditions and, although they warn of potential crisis, are also opportunities for innovation. Potential water resource–related focusing events across the western United States include: (1) extreme climatic conditions (e.g., drought and floods); (2) large-scale inter-basin transfers; (3) quantification of tribal water rights; (4) an energy crisis; (5) changing transboundary responsibilities; and (6) regula- tory mandates such as the Endangered Species and Clean Water Acts. Crisis conditions can be said to be reached when focusing events occur concurrently with public awareness of a finite time necessary for effective response. In this context, institutional conditions that limit flexibility tend to exacer- bate the underlying resource issues. We begin with a broad overview of the history of Colorado River basin development and the scales of decision making (governance and operational requirements) involved. The decision-making environments are discussed in terms of drought-sensitive issues at international, inter-state, Native American, and state levels. The development of the Colorado River Compact (and its use of a limited record of streamflow) mentioned above is discussed in great detail in numerous books and articles (see Weatherford and Brown, 1986) and will be referred to here only when it introduces a criticality to the management problem being considered. Two issues that were not in the original compact but have since become more important will be addressed in some detail: conjunctive use (i.e., joint use of surface and groundwater) and water quality. II. SOCIAL AND ECONOMIC CONTEXTS Demographic, legal, and environmental changes can and have disrupted existing relationships and current perspectives about the interactions among society, climate, and water. Nowhere is this more apparent than in the many transbound- ary situations that dominate Colorado River management. The Colorado River has been the subject of extensive negoti- ations and litigation. The federal government accounts for DK2949_book.fm Page 254 Friday, February 11, 2005 11:25 AM Copyright 2005 by Taylor & Francis Group The Hardest Working River 255 56% of the land within the basin; Indian reservations, 16.5%; states, 8.5%; and private ownership, 19% (Weatherford and Brown, 1986). As a result, a complex set of federal laws, compacts, court decisions, treaties, state laws, and other agreements collectively known as the “Law of the River” has been developed (Table 1). These play out in terms of inter- state agreements (e.g., the Colorado River Compact) and tran- snational (U.S.–Mexico) settings. A study by an alliance of seven western water resources institutes (Powell Consortium, 1995) offers the following counterintuitive result: Although the Lower Colorado River Basin within the United States is indeed drier than the Upper Basin, it is the Upper Basin that is vulnerable to severe, long-term climatological drought because of the 1922 agreement to provide a fixed amount of water to the Lower Basin. However, the Lower Basin is subject to water supply limitations brought on by growth and inflex- ible allocation arrangements. This unprecedented growth has occurred during a wetter-than-average 25-year period (1975–99), which may have resulted in some degree of com- placency about water availability. The chronology in Table 1 reflects the changing values of water rights in the new West based on tourism and recre- ational economies. Management has evolved from two classic approaches to integrated river basin development: (1) large- scale investments in water projects integrating economic and engineering objectives, and (2) negotiation of inter-state and international agreements for the management of shared resources. Recently, emphases have shifted to integration of irriga- tion with other agricultural land uses, wastewater reuse, and conjunctive management of ground and surface water sys- tems. Most important are the trends toward public involve- ment and participation in decision-making processes and the incorporation of institutional and behavioral considerations in the planning and implementation processes. Frederick et al. (1996) concluded that in the upper Col- orado region the value of water for recreation, fish, and wild- life was US$51 per acre-foot, compared to US$21 for hydropower and US$5 for irrigation. Even given the limited DK2949_book.fm Page 255 Friday, February 11, 2005 11:25 AM Copyright 2005 by Taylor & Francis Group 256 Pulwarty et al. T ABLE 1 The Colorado River: Relevant Events and Agreements, 1902–2004. 1902 Arthur Powell Davis, USGS engineer (future head of the Bureau of Rec lamation), proposes “the gradual comprehensive development of the Colorado by a series of large storage reservoirs .” 1905 Flood waters break into Imperial Valley, creating the Salton Sea over 2 years. 1919 Kettner Bill authorizes building of aqueduct. 1920 Kincaid Act authorizes data gathering for the All-American Canal. Population of Los Angeles reaches 600,000 (600% more than in 1900). Mulholland and Scattergood endorse Da vis’s plan to use Colorado to meet “all future electricity needs.” Denver population reac hes 260,000 (100% increase since 1900). 1922* Colorado River Compact. Upper and Lower Basins demarcated at Lees F erry. All basin states except Arizona ratify agreement. Indian rights considered “negligible .” 1923 Dry year. Los Angeles looks to Colorado for w ater as well as electricity. 1927 Metropolitan Water District of Southern California approved by state legislature . 1928* Boulder Canyon Act (BCA) approved in Congress . Authorizes construction of Hoover Dam. 1922 compact ratified. Lower Basin allotments apportioned. 1930 Arizona v. California. Arizona requests that the BC A be declared unconstitutional. 1931* California Seven Party Agreement on municipal vs . agricultural use 1935 Hoover Dam completed. California purchases all power produced. 1944* Colorado River Compact ratified by Arizona. 1945 Mexican Treaty approved in Congress, with support from Upper Basin, Arizona, and Texas. Mexico receives 1.5 maf despite objections from California. 1948* Upper Basin Compact: Allots Colorado 51.75%, Utah 23%, Wyoming 14%, New Mexico 11.25% (and 50,000 af to Arizona above Lees Ferry). 1956* Colorado River Storage Project Act. Arizona v. California . 1963 Glen Canyon Dam completed. Lake Powell begins filling . Indian uses charged against the state in which a reservation was located. 1964 Arizona v. California Supreme Court decision. Settles 25-year dispute. Allows Arizona’s decision to build the Central Arizona Project (CAP) to fully use its allotment. DK2949_book.fm Page 256 Friday, February 11, 2005 11:25 AM Copyright 2005 by Taylor & Francis Group The Hardest Working River 257 1968* Colorado River Basin Project Act. Construction of major w ater developments in both Upper and Lower Basins. CAP designated junior right. 1970* Criteria for Coordinated Long-Range Operation of Colorado River System. Glen Canyon Dam releases to maintain balance between Lake Powell and Lake Mead. 1973* Minute No. 242 of the U.S.–Mexico International Boundary Commission. 1974* Colorado River Basin Salinity Control Act. Authorized desalination and salinity control projects (inc luding Yuma Desal Plant). 1987 Increased generator capacity and resulting c hanges in operations require environmental impact statement (EIS) for Glen Canyon Dam. 1994 Draft EIS issued. U.S. Fish & Wildlife Service BiOp on Glen Canyon operations . 1996 Controlled flood released from Glen Canyon Dam. 2001 Colorado River Interim Surplus Guidelines. Surplus in Lower Basin to be divided between California and Arizona. Quantification Settlement Agreement. 2004 Worst drought period in 100 years continues (since 1999). Note: Asterisked (*) years denote passage of principal documents forming the “Law of the River.” DK2949_book.fm Page 257 Friday, February 11, 2005 11:25 AM Copyright 2005 by Taylor & Francis Group [...]... surface water and groundwater are considered public resources subject to state law, with rights and permits to use water granted to individuals and water providers Owners of water delivery and treatment infrastructure are typically not the states but local governments or private water companies and irrigation districts A better understanding of the links between domestic concerns in both countries and. .. 50 100 years and precipitation measurements over the last 20–60 years Water managers often lack even basic data on water quantity and quality, the nature of climate variations, and their impacts on water users and uses, and thus have little basis for designing effective management programs (Jacobs and Pulwarty, 2004) More specific forecasts are needed for different regions and sectors to assist water. .. overuse These include pricing structures to promote water use efficiency; measurement of water usage; audits of commercial, domestic, and industrial uses; water reuse and recycling; management of water system pressure; retrofitting and replacement of water fixtures; promotion of water- efficient appliances; improving infrastructure quality; conservation; and conservation education As Gleick et al (2002) showed,... now available on biweekly, monthly, and seasonal to interannual scales and are improving in skill over time Demand forecasts are equally important and need to be undertaken for 5-, 1 0-, and 20-year horizons Given recent advancements in understanding climate variability and change, it is clear that such projections must be made in the context of the greater than 10 years timescales of climate variations... climate/hydrology and water resource supply and demand along the border; and (3) develop an evaluation of socioeconomic data and projections of socioeconomic and demographic changes over the next 25 years in terms of potential impact on water supply and demand As Wilhite repeatedly warns, reactive mechanisms such as drought relief do little if anything to reduce the vulnerability of the affected area to future drought. .. Conservation and demand management approaches range from technology interventions for specific problems to regional water basin planning, including mandatory, voluntary, and incentive-based approaches (Luecke et al., 2003) The innovations described above (the AWBA/AWS/CAGRD, BECC, the QSA settlement) are based in water management planning and provide institutional mechanisms to reduce vulnerability to drought, ... Governments Water Wars: Trends Alerts Lexington, KY, 2003 Department of the Interior Water 2025: Preventing Crises and Conflict in the West http://www.usbr.gov/centennial/, 2003 Dracup J Impact on the Colorado River Basin and Southwest water supply In: National Research Council, Climate Change and Water Supply (p 121) Washington, D.C.: National Academy Press, 1977 el-Ashry M, D Gibbons Water and Arid Lands... considerations, and the third is drought Other water quality issues of recent concern along the Colorado include coliform contamination from inadequate waste treatment, limiting certain recreational activities, and perchlorate contamination that has leached into the water supply from an industrial point source near Las Vegas Neither is directly related to drought, but they may have drought and water supply... implications for water resource use and management in the basin Potential effects include changes in average annual snowpack (water storage) and evaporation, alterations in the magnitude and timing of the annual hydrological cycle (e.g., of peak flows), and additional water requirements to meet urban and agricultural needs The Powell Consortium (1995) study of the potential effects of severe sustained drought. .. al., 2001) Climate-sensitive decisions in the Colorado River basin thus involve and cross the many temporal and spatial scales through which water of varying quantity and quality flows (Pulwarty and Melis, 2001) A Water Quantity As a result of climatological droughts experienced during the 1930s, 1950s, and 1970s, the Colorado system as a whole is operated to maximize the amount of water in storage for . international issues; (2) Arizona and Califor- nia: interstate issues in the Lower Basin; (3) Native American water rights; and (4) conjunctive use and management: groundwater and surface water in. irriga- tion with other agricultural land uses, wastewater reuse, and conjunctive management of ground and surface water sys- tems. Most important are the trends toward public involve- ment and. surface water and groundwater are considered public resources sub- ject to state law, with rights and permits to use water granted to individuals and water providers. Owners of water delivery and