Southwest Hydrology: The Resource of Semi-Arid Hydrology Volume 4 Number 2

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Inside This Issue Departments 8 On the Ground • Interbasin groundwater flow, southern AZ • Controlling acid rock drainage 11 HydroFacts 12 Government • USDA funds salinity control • AZ, tribes settle water disputes • Nevada to bank water in AZ • NM enviros become farmers 14 PoinVCountemoint • Hetch Hetchy Valley restoration 30 The Society Pages • GSA names Birdsall- Dreiss lecturer • California Dream awards • ACWA lifetime awards • CUAHSI activities 32 People • Bouwer wins international prize • Campbell a GSA fellow • Harder heads CA flood management • Ganster chairs GNEB 33 Crossword Puzzle 34 Business Directory and Job Opportunities 36 R &D • Perchlorate in AZ waters • Water innovation grants in NM • Contaminant source tracking accuracy questioned • Energy cost of CA water 39 Education • A water quality lesson for the classroom 40 In Print Groundwater Recharge in a Desert Environment, reviewed by Tim Parker 41 Software Review MT3DMS, reviewed by Henning Prommer 42 The Calendar 6 • March /April 2005 • Southwest Hydrology Drought on the Colorado River In 2004, Lake Mead and Lake Powell both experienced their lowest reservoir elevations since Lake Powell was filled in the late 1960s. Although the 2005 water year looks more favorable than the previous five drought years, it would take about a decade of average flows for the reservoirs to recover. Water supplies, water quality, and power supplies already have been affected throughout the Colorado River Basin. As the possibility looms of a true shortage in which states face reduced allocations, the need for better accounting and more accurate hydrologic data comes to the forefront. Rather than each state fighting for its individual share, as occurred in the past, states now are working together to face not just the current drought, but to improve long -term management of the river. 16 How low Can It Go? Terry Fulp System -wide storage on the Colorado River is currently about 50 percent of capacity. Power generation at Hoover Dam is down 20 percent from 1999. How much lower can reservoir levels go before these and other resources are completely cut off? 18 Upper Colorado River Basin Perspectives on the Drought Don A. Ostler Some uses of Colorado River water in the Upper Basin have been curtailed because of the drought, yet the conditions for declaring and distributing a shortage on the river have never been determined. Colorado River Compact accounting is needed so cooperative planning throughout the basin can take place. 19 The Law of the River A summary of important documents and legal decisions that govern Colorado River allocations. 20 Colorado River water Supplies: Back to the Future Eric Kuhn The Colorado River is operated under an assumed 15 million acre -feet average annual undepleted flow at Lees Ferry, but tree -ring and other data indicate that 13.5 maf may be a more realistic long- term average. High -flow years will still occur, but perhaps now is the time to reconsider the long -term management of the river. 22 The Effects of Drought on Lower Basin River Operations Rita Maguire Much has been made of recent agreements between Lower Basin states to address the pressures growth has placed on the limited water supplies of the Colorado River. But a new threat is testing the states' ability to resolve water management issues. Drought has changed the dynamics of what were once considered well thought -out, long -range water agreements. 24 SSD Redux? Comparison of a Historic Drought under Modern Management to the Current Drought Ben Harding Lake Mead is substantially lower today than a model of a theoretical severe and sustained drought predicted. How do the model and present conditions compare, and what are the implications for the future? 26 Effects of the Drought on Water Quality in Lake Mead Peggy Roefer, Kim Zikmund, Tom Maher, and Jim LaBounty A reduced water supply isn't the only effect of drought on the Colorado River. As the water concentrates in ever - shrinking reservoirs, treatment challenges increase. The Las Vegas Valley has been particularly affected. This material Is based Won work supported by SAHRA (Susfainablliry of semi -Add hydrology and Riparian Areas) under the STC Program of the National Science Foundation, Agreement No. EAR - 9876600. 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.