Acre Feet Research Articles

How much water can be captured from flood flows to store in depleted aquifers for mitigating floods and droughts? A case study from Texas, US

Extreme flooding from Hurricane Harvey (∼100 km3, ∼80 million acre feet, maf of rainfall) in Houston, Texas, US co-located with depleted aquifers raises the question of whether we can capture floodwater to reduce flooding impacts and replenish aquifers for droughts. Here we quantified how much water could be captured from high magnitude flows (HMFs) in 10 major rivers discharging to the Gulf of Mexico for potential storage in depleted aquifers along the Texas Gulf Coast. Results show that HMFs (≥95th percentile) from rivers discharging to the Gulf of Mexico total 37 km3 (30 maf) in 2015–2017, similar in capacity to US Lake Mead (32 km3, 26 maf). These flows are less than modeled unappropriated flows that consider appropriated water rights and limited analysis suggests moderate reduction from environmental flows. Similarity in high flow volumes and modeled groundwater depletion in the Gulf Coast Aquifer system (∼25 km3, 20 maf) underscores the potential to partially mitigate flooding using aquifer storage. Interim storage would be required to resolve disconnects between high flood intensities and low aquifer injection rates. Engineering approaches will become increasingly important to manage climate extremes.

Optimal design and operation of River Basin Storage

The State of Colorado’s Stream Simulation Model (StateMod) provides comparative analysis for historical and future water resource decisions and policies along the Lower South Platte River. In order to identify locations for increased water storage, our research uses simulated data produced by StateMod as input to a mixed integer-linear optimization model. This model minimizes the cost of meeting unmet demands by assigning network flow of, and designing additional storage for, excess water while adhering to constraints that force the physical and topographical structures of the river. Using historical, measured flow data from 1962 through 2012, we extend the capability of StateMod by considering solutions with the following characteristics: (1) a single-reservoir solution, (2) a solution in which we only expand existing reservoirs, and (3) a solution without the constraints in (1) or (2). We conclude that, for the time horizon considered, the optimal method to mitigate shortages is with the construction of a combination of smaller surface and sub-surface reservoirs, and a corresponding prescribed flow. The total increased storage volume is 25,378 acre-feet (AF). Our work can be used as a strategic analysis tool by planners and engineers to quickly identify the most effective reservoir locations and the order in which to build them, rather than examining every potential storage site and the time at which it should be built, if at all.

Satellite Image Used to Solve the Impact of Silt and Velocity on Discharge Carrying Capacity of Right Bank Canals of SukkurBarrage Pakistan

Pakistan is basically an agricultural country, agriculture is considered the back bone of the country. It helps country in earning foreign exchange, about 90% of output comes from agriculture, supports in employment and economy by exporting food grains. Luckly Pakistan has worlds third giant irrigation system, it comprises best storage infra-structure, controlling system of barrages, regulators, conveyance system of canals and an efficient drainage system both horizontal and vertical. Indus river basin irrigation system has three major reservoirs, sixteen barrages, two head works, two siphons across major rivers, 12 inter river link canals and 44 irrigation canals. Average gradient was observed from sea level as flat with rate of 12.5 cm/km (eight inches/mile), Indus provides irrigation system to major portion of Sindh almost 41 percent. The total Gross Commanded area of Sindh and Baluchistan which depends on Indus is 5.92 Mha whereas, the only Cultivable command Area is 5.43 Mha. The major crops grown in Sindh are rice in Kharif and wheat in Rabi. Besides this, Sindh also produces horticultural crops such as: mangoes, bananas, dates and chilies. Sindh has also diversion capacity of 111 billion cubic meter (BCM) which is equivalent to 90 million Acre Feet (MAF). It was found in the research that excess of silt in Right Bank Canal is more to reduce the velocity of water. Satellite image based model shows negligible velocity to Right Pocket at Sukkur Barrage. 60% less cultivation in 2018 at SaifullahMagsi Branch Division at border of Sindh-Balochistan.

Use of Radiocarbon Ages to Narrow Groundwater Recharge Estimates in the Southeastern Mojave Desert, USA

Estimating groundwater recharge in arid or semiarid regions can be a difficult and complex task, since it is dependent on a highly variable set of spatial and temporal hydrologic parameters and processes that are dependent on the local climate, the land surface properties, and subsurface characteristics. As a result, traditional methods for estimating the recharge can result in a wide range of derived values. This is evident in the southeastern Mojave Desert, where calculated recharge estimates by previous investigators that range over an order of magnitude (from ~2500 to ~37,000 acre feet per year) are reported. To narrow down this large span of recharge estimates to narrower and more plausible values, this study evaluates the previous recharge estimates in this region, to examine the sources of variability in the reported results and to constrain the recharge estimates based on the hydrologic conditions and the radiocarbon age-dating of spring flows—even without knowledge of the precise subsurface hydrology. The groundwater age and perennial flow characteristics of springs in this study could not be derived from waters sourced solely from local recharge. Therefore, the springs in this study require a significant groundwater contribution to their overall discharge. A previously described conceptual site model in the region established that Bonanza Spring is similarly hydrologically connected to the regional basin-fill aquifer, based on geologic and geochemical/isotopic analyses, and this conceptual site model for where perennial spring water is sourced should readily be extended to these other perennial springs in this region.

Impact of Ridge-Furrow Planting in Pakistan: Empirical Evidence from the Farmers Field

Wheat is planted through the broadcast method on 7.8 million ha and irrigated through low-efficiency flood basin irrigation methods. With decreased water availability, there is a need to adopt water use efficient planting techniques. The current paper uses two-year trials data set as well as farmer survey data to demonstrate benefits of ridge-furrow planting wheat and farmer perception regarding the technology in Pakistan. During 2014–15 and 2015–16, ridge-furrow planting of wheat was compared with farmer practice of planting on flat surface through broadcasting at 162 sites located in 15 districts of Pakistan. In a survey, 134 farmers shared their experiences about ridge-furrow planting. Data collected from field trials and demonstrations showed that better tillering and crop growth contributed towards 12% higher wheat grain yield with ridge-furrow planting in comparison with the farmer practice of flat planting in all 15 districts during both years. Furrow-irrigated ridge planting of wheat helped farmers in saving of 30–35% water in comparison with farmer practice. Farmers adopting ridge-furrow wheat planting earned USD 100.63 per hectare more profit than nonadopter farmers. Adoption of this technology on one million hectare can help in saving 1 million acre foot of water and produce additional 0.36 million tons of wheat per year.

Economic Feasibility Assessment of Winter Cloud Seeding in the Boise River Drainage, Idaho

The Boise River Drainage, located in Central Idaho, is productive in terms of annual streamflow, a large majority of which is derived from accumulated winter snow pack. There are three dams in the upper river: Anderson Ranch, Arrowrock and Lucky Peak. Capacities of the three reservoirs are: 413,000, 272,000 and 306,000 acre feet, respectively. Both Anderson Ranch and Lucky Peak have hydroelectric production capabilities. Lucky Peak is located below the first two dams. North American Weather Consultants, Inc. conducted winter cloud seeding programs over the Boise River Drainage above Lucky Peak Reservoir during the water years of 1993-1996. A target/control analysis of these four seasons of seeding indicated an average increase in target area April 1st snow water content of 12% (an average additional 2.50" of snow water content per season). Additional analyses were performed to estimate the potential economic benefit that might be derived from the seeding program based upon the value of the estimated increased hydro-power production from Lucky Peak Dam. Lucky Peak has an installed turbine capacity of 100 MW. It was estimated that a 12% increase in April 1st snow water content would result in an average 16,409 MWh of additional electricity production per year. This amount of additional electricity was estimated to have a value of $820,182. The average annual cost of the cloud seeding program during the four seasons of operations was $85,000. These values result in an average estimated benefit/cost ratio of 9.7/1. This analysis does not consider the value of the additional electricity produced from the Anderson Ranch Dam, which is a Bureau of Reclamation facility, or the value of the enhanced streamflow to irrigation interests downstream of the Lucky Peak Dam.

SEDIMENT CORE SAMPLING AND ANALYSIS OF KAW LAKE

The Kaw Nation and Black land Research Center in July 2012 conducted a sediment core sampling from Kaw Lake. Kaw Lake is a reservoir constructed in 1976 by the Army Corps of Engineers for the purpose of water supply and recreation. It is locat ed 11 miles east of Ponca City, Kay County, Oklahoma. This reservoir covers approximately 17,040 acres (69 km 2 ) and is also known to be the seventh largest lake in Oklahoma by surface area. T his lake holds 428,600 acre feet (528,700, 00 m 3 ) of water which is said to be the ninth largest lake in Oklahoma. The lake is fed by the Arkansas River that flows from Colorado, through kansas and into K aw Lake. The Arkansas River flows through Kaw Lake shared by several small creeks and empties int o the Mississippi River. The purpose of the study was to determine the rate of sediment accumulation and examine the level of nutrient and heavy metals accumulation or deposition at the bottom of the lak e. Four core samples from different parts of the la ke at different depth were sampled for analysis. Each cor e sample was sectioned into 20 cm, dried and ground into homogenous powder. Samples from each section were tested for organic carbon content and heavy metals. Organic carbon content was verified by burn ing through a muffle furnace, while the remaining core samples were digested into a solution and ran through an Atomic Absorption Spectrophotometer (AAS) to evaluate the concentration of heavy metals . Particle size analyses were also determined. Results were organized by depth, concentration, par ticle size distribution and bulk density. Data show ed phosphorous and some heavy metals concentrations at core 3 and 4 were higher than core 1 and 2. Phosphorous concentration at four sediment core sit es ranged from 350 mg kg -1 to 550 mg kg -1 . Whereas Aluminum concentration was 40,000 mg kg -1 to 70,000 mg kg -1 , Barium 280 mg kg -1 to 420 mg kg -1 , manganese 600 mg kg -1 to 710 mg kg -1 , iron 30,000 mg kg -1 to 48,000 mg kg -1 are few to be cited. Bulk density, a measure of soil mass per uni t of volume of soil in a water increased with water depth as the water content decreased.

Economic Value of Instream Flow for Non-Commercial Whitewater Boating Using Recreation Demand and Contingent Valuation Methods

Whitewater river kayaking and river rafting require adequate instream flows that are often adversely affected by upstream water diversions. However, there are very few studies in the USA of the economic value of instream flow to inform environmental managers. This study estimates the economic value of instream flow to non-commercial kayakers derived using a Travel Cost Method recreation demand model and Contingent Valuation Method (CVM), a type of Contingent Behavior Method (CBM). Data were obtained from a visitor survey administered along the Poudre River in Colorado. In the dichotomous choice CVM willingness to pay (WTP) question, visitors were asked if they would still visit the river if the cost of their trip was $Y higher, and the level of $Y was varied across the sample. The CVM yielded an estimate of WTP that was sensitive to flows ranging from $55 per person per day at 300 Cubic Feet per Second (CFS) to a maximum $97 per person per day at flows of 1900 CFS. The recreation demand model estimated a boater's number of trips per season. We found the number of trips taken was also sensitive to flow, ranging from as little as 1.63 trips at 300 CFS to a maximum number of 14 trips over the season at 1900 CFS. Thus, there is consistency between peak benefits per trip and number of trips, respectively. With an average of about 100 non-commercial boaters per day, the maximum marginal values per acre foot averages about $220. This value exceeds irrigation water values in this area of Colorado.

Fate of selenium in a small urban watershed

A field study was conducted on a small urban watershed (residential and golf course dominated) in southern Nevada to assess the concentration and speciation of selenium (Se) in a series of drain lines and monitoring wells and to quantify the mass discharge of Se from the drain system. Water samples were collected on a monthly basis and analyzed for total Se, selenate (SeO4 (=)) and selenite (SeO3 (=)). In addition, where possible, flow was assessed as was, temperature, redox potential, pH, dissolved oxygen (DO) along with all major cations and anions. The data were then modeled with PhreeqC to identify selenium speciation. Results revealed a SeO4 (=) dominated system with SeO4 (=) concentrations ranging from 13 to 62 ppb. In the monitoring wells, 66 % of the variation in the total Se concentration could be described based on depth to groundwater, temperature and sulfate concentrations (P < 0.001). In particular, higher total Se concentrations were predicted for shallower depth to groundwater, suggesting the solubilization of Se evapo-concentrates near the surface could be reduced by lowering water tables. The highest of all correlations was found between SeO4 (=) concentrations (↑) and the sodium (↑) and DO (↑) concentrations in the monitoring wells (R (2) = 0.77, P < 0.001). An excellent curvilinear relationship was found between total Se and the electrical conductivity in the water (R (2) = 0.73, P < 0.001). Based on the Se data and time line identified in this study, high concentrations of Se could be expected to drain from this area for many years to come, with salinity acting as a good proxy for Se concentration. In the drain lines, Se concentrations were found to be invariant to flow (P > 0.05). Flow discharge from the main drain system to the Las Vegas Wash was estimated at 559 acre feet during the 1 year study period. This flow was estimated to carry 4,203 Mg of salts 6.71 Mg of nitrate-N and 27.1 kg of total Se.

Feasibility of Groundwater Banking under Various Hydrologic Conditions in California, USA

This study evaluates the feasibility of groundwater banking in the Central Basin. The Central Basin is located in Sacramento County in northern California, USA. The study basin is bounded by three rivers (the Sacramento, the American, the Consumes and Mokelumne rivers), and by the Sierra-Nevada mountain range. This study focuses on the potential for groundwater recharge in the Central Basin for three water years (critical, wet, above normal). For that purpose, a 3-D Groundwater Modeling System (GMS) with MODFLOW was created. Three recharge wells were added to the calibrated groundwater model to recharge the water table with 10,000 Acre-Feet (AF) of water to the Central Basin. The banking of 10,000 AF during the critical and wet years was effective in raising the water table elevation in the cone of depression area without causing any negative impact elsewhere in the basin. According to the findings of the Central Basin model, banking up to 10,000 AF of groundwater during any year type is feasible. More than 10,000 AF of groundwater banking might cause more negative impacts than positive benefits.

Rebuilding for the next 100 years

Smith-Lever Act of 1914: An Act to pr colleges in the several States receiving and sixty-two, and of acts suppleme Outlook Outlook Rebuilding for the next 100 years • researching how to make safe, affordable food available to the world’s 7 billion people; • protecting scarce natural resources; • building healthy, prosperous communities; and • educating our future leaders to meet these and to- morrow’s challenges. n 2014 our nation commemorates the 100th anni- versary of the founding of Cooperative Extension. In many ways ANR functions as UC’s 11th cam- For the University of California’s Division of Ag- pus. We don’t grant degrees, but we educate more riculture and Natural Resources (ANR), this is both a than 150,000 California young people every year in year for celebration and for renewal. the California 4-H Youth Development Program. As California’s land-grant research university, UC, One of the original Cooperative Extension programs, in 1914, was given the task of building the Extension 4-H teaches science, engineering, nutrition, ecology system that the Smith-Lever and good citizenship. By participating in 4-H, young Act envisioned would pro- people increase their likelihood of graduating from pel U.S. agriculture into college fivefold. For 100 years, UC Cooperative the modern era. UC ANR ANR doesn’t operate medical centers, but we work Extension has served as ANR’s embraced that vision with a every day to fight childhood obesity and poor nutri- “community ambassador.” prophetic belief that scientific tion. Our Extension nutrition programs reach more knowledge could, indeed, than 222,000 adults and children in 33 counties. transform California into the Through UC Cooperative Extension’s efforts, world’s most successful agri- over the past three decades California’s milk produc- cultural producer. tion has increased 44%; its processing tomato yields For 100 years, UC have increased 69% and almond yields have risen Cooperative Extension has by 122%. served as ANR’s “commu- Using ANR-developed technology, California grow- nity ambassador,” deliver- ers save 100,000 acre feet of water a year. ing research and education When invasive pests like the Asian citrus psyllid programs in every California attack crops, ANR fights back with scientific advances county. During this centen- in pest management and ongoing research to eradicate nial year, we have much the threat. to celebrate, thanks to our Even in times of severe budget cutbacks, ANR con- storied history and the sistently fulfills its public service responsibilities. The 1,350 dedicated individuals university and ANR have suffered through chronic who make UC Cooperative funding declines that have threatened the quality of Extension and all of our programs and ability to serve the state. Now that ANR thrive. California’s finances are improving, we must focus Today, we operate nine on renewal. Research and Extension Among my highest priorities as vice president is Centers, 60 county offices and to rebuild the academic footprint of UC Cooperative three administrative centers, Extension. To sustain UC’s credibility with the people with more than 11,000 acres, it was created to serve, we must continue to replen- 320 Extension researchers ish our ranks (see next page) and revitalize programs and 650 campus-based aca- trimmed during lean budget years. demics devoted to sustaining We also must forge new public-private partnerships UC ANR researcher and improving California’s and strengthen the ones we have to attract diversified checking codling funding sources to our programs. moth trap in a walnut agricultural and natural resources. Through this vast statewide network, ANR deliv- And we must build collaborations within the UC tree at sunrise ers practical, science-based information to California campuses to take advantage of the multidisciplinary growers, ranchers, decision makers and, perhaps most nature of transformative research. importantly, the people of California. These are some of the challenges that keep me Through our partnerships with the agricultural awake at night. We must accomplish these goals and community; state, local and federal agencies; and the more if UC Cooperative Extension and all of ANR are California State University, we address some of the to contribute another 100 years to the health and vi- most pressing problems of our day, including brancy of the California we all treasure. Barbara Allen-Diaz Vice President Division of Agriculture and Natural Resources University of California Jack Kelly Clark I 6 CALIFORNIA AGRICULTURE • VOLUME 68 , NUMBERS 1–2

Climate change and managing water crisis: Pakistan’s perspective

Climate change is a global phenomenon manifested mainly through global warming. The International Panel on Climate Change (IPCC) has reported its negative consequences on natural resources, anthropogenic activities, and natural disasters. The El Nino and La Nina have affected hydrologic regimes and ecosystems. It has been observed that the average temperature in 1995 was 0.4°C higher than that in 1895. By the end of the 21st century, 10% of the area of Bangladesh is likely to be submerged by the sea. Most of the islands of Pacific Ocean will disappear. A major part of Maldives will be submerged. The sea level is expected to rise by 30-150 cm. Extreme events such as floods, cyclones, tsunamis, and droughts have become regular phenomena in many parts of the world. Other adverse impacts are proliferation of water-borne diseases, sea water intrusion, salinization of coastal areas, loss of biodiversity, eco-degradation of watersheds and global glacial decline, and haphazard snow melts/thaws. In turn, these factors have serious effect on water resources. Pakistan is confronting similar climate change. Meteorological data reveal that winter temperatures are rising and summers are getting cooler. Temperature is expected to increase by 0.9°C and 1.5°C by years 2020 and 2050, respectively. Water resources in Pakistan are affected by climate change as it impacts the behavior of glaciers, rainfall patterns, greenhouse gas emissions, recurrence of extreme events such as floods and droughts. Severe floods have occurred in the years 1950, 1956, 1957, 1973, 1976, 1978, 1988, 1992, 2010, 2011, and 2012. Pakistan has faced the worst-ever droughts during the period from 1998 to 2004. Pakistan has surface water potential of 140 million acre feet (MAF) and underground water reserve of 56 MAF. It is one of the most water-stressed countries in the world. The per capita annual availability of water has reduced from 5140 m3 in 1950 to 1000 m3 now. It is fast approaching towards water scarcity. To minimize adverse impacts of climate change on the water crisis in Pakistan, the preparation of integrated national, provincial, and local level master plans encompassing technical, social, environmental, administrative, and financial considerations is necessary. It is imperative to implement two simultaneous approaches of adaptation (living with climate change) and mitigation (addressing negativities of climate change). Salient features are integrated management of watersheds/catchments/water bodies, optimum exploitation of present sources, development of new sources, water conservation, adequate drainage, efficient design of water storage, conveyance, distribution and supply systems, utilization of waste water, and regulation of water quality.

Controls on Water Use for Thermoelectric Generation: Case Study Texas, U.S.

Large-scale U.S. dependence on thermoelectric (steam electric) generation requiring water for cooling underscores the need to understand controls on this water use. The study objective was to quantify water consumption and withdrawal for thermoelectric generation, identifying controls, using Texas as a case study. Water consumption for thermoelectricity in Texas in 2010 totaled ∼0.43 million acre feet (maf; 0.53 km3), accounting for ∼4% of total state water consumption. High water withdrawals (26.2 maf, 32.3 km3) mostly reflect circulation between ponds and power plants, with only two-thirds of this water required for cooling. Controls on water consumption include (1) generator technology/thermal efficiency and (2) cooling system, resulting in statewide consumption intensity for natural gas combined cycle generators with mostly cooling towers (0.19 gal/kWh) being 63% lower than that of traditional coal, nuclear, or natural gas steam turbine generators with mostly cooling ponds (0.52 gal/kWh). The primary control on water withdrawals is cooling system, with ∼2 orders of magnitude lower withdrawals for cooling towers relative to once-through ponds statewide. Increases in natural gas combined cycle plants with cooling towers in response to high production of low-cost natural gas has greatly reduced water demand for thermoelectric cooling since 2000.

Comparing households’ total economic values and recreation value of instream flow in an urban river

The empirical importance of non-use values relative to use values appears to vary by uniqueness of the natural environment being valued. At one extreme is the Grand Canyon, where non-use values are orders of magnitude higher than use values. For protecting water quality used for water-based recreation and drinking water, non-use values are still significant, but about half the magnitude of these two use values. In this paper we investigate the relative importance of non-use values for maintaining instream flows in an urban river in the City of Fort Collins, Colorado, USA. At the request of the City Council, a contingent valuation method (CVM) survey was conducted. A dichotomous choice CVM survey of households estimated that the Total Economic Values (TEV – sum of non-use and recreation) of city households is $234 per year. A second CVM question specifically about recreation use value of the same households yielded an estimated annual WTP of $90 per year. Thus, the TEV to maintain current instream flow is 38% recreation value and 62% non-use values, suggesting the importance of non-use values even for a non-unique, but locally significant urban river. Summing up the TEVs per household in the city yields an annual value of $171 per acre foot, several times larger than annual water lease rates in Northern Colorado. However, the present value of this TEV per acre foot is less than the price for purchasing water rights in order to maintain instream flows. Thus, unless the City of Fort Collins partners with downstream cities, who would also benefit from instream flows, annual leases are the most efficient option for maintaining instream flows.

Stability and Bifurcation Analysis of Reservoir Sedimentation Management

The alarming loss of water storage capacity to sedimentation in reservoirs worldwide is prompting a paradigm shift toward sustainable management. Previous research has investigated the physical capability of various technologies to control reservoir sediment, and formulated economic rules governing their optimal sustainable use. We ask the next rele- vant questions: Is sustainable reservoir management structurally stable for particular technologies, or do thresholds exist such that small perturbations in key management parameters abruptly unleash dynamics driving the reservoir toward ex- tinction? What are the dynamic properties of reservoirs in transition? We uncover a saddle-node bifurcation for the par- ticular case of a multi-purpose public reservoir manager who adopts the environmentally friendly 'hydrosuction-dredging' sediment removal technology. Beyond the bifurcation threshold, sustainable management abruptly gives way to eventual loss of storage capacity to sedimentation. Reservoirs throughout the world suffer from sedimenta- tion. Examples include estimated annual storage capacity losses of 2.3% in China (2), 0.5% in India (2), and 1% worldwide (3). Specific examples are catalogued by Batuca and Jordaan (4). These include the Cir-lurtsk Reservoir on the Sulak River (Russia) which was 95% sedimented in 7 years; the Gumati Reservoir on the Vakhs River (Georgia) which was 90% sedimented in 11 years; and the Zemo Af- char Reservoir at the confluence of the Kura and Aragi Riv- ers (Russia) which lost 44% of its initial storage capacity in the first 2 years, 32% in the next 8 years, and 3.5% up to 1967. Other examples include the Tarbela Dam on the Indus River—the most important facility of its kind in Pakistan— which lost 20% of its storage capacity after 23 years of op- eration (5); and the Matilija Dam in California whose storage capacity decreased from 7,000 acre feet in 1947 to less than 500 acre feet by 2005 (6).

Water Reallocation in the West: An “Inconvenient” Truth?

Water Reallocation in the West: An “Inconvenient” Truth?

Review: Dead Pool: Lake Powell, Global Warming, and the Future of Water in the West

Review: Dead Pool: Lake Powell, Global Warming, and the Future of the West By James Lawrence Powell Reviewed by David Jenkins Roundhouse Institute for Field Studies, USA Powell, James Lawrence. Dead Pool: Lake Powell, Global Warming, and the Future of the West. Berkeley, CA: University of California Press, 2008. 283 pp. ISBN 9780520254770. US$27.50, cloth. Acid-free paper. The history of Lake Powell is a history of failure, near failure, and, at best, limited and short-term success. The near failure, with which James Powell begins his book, was the potential collapse of Glen Canyon Dam in 1983. An overfull reservoir required the use of two spillway tunnels carved through the sandstone adjacent to the dam. The massive release of water caused the spillways to begin to fail, potentially eroding the soft sandstone and undermining the integrity of the dam. If the dam failed, the result would be a cascading disaster, as dams below Lake Powell collapsed in turn under the onslaught of a massive flood. Runoff, however, slowed to manageable levels at the end of the summer. This averted catastrophe serves as a potent point of departure for James Powell’s description of the many failures which led to the construction of Glen Canyon Dam. These include Congress’s failure to heed the advice of John Wesley Powell in the late nineteenth century concerning the West’s limited capacity for irrigation; the early twentieth-century failure to enforce the provisions of the 1902 Newlands Act, which provided funds for irrigation works to be repaid by farmers who bought irrigable public lands; the governmental failure to estimate with precision the costs and benefits of huge water projects; the failure to accurately measure Colorado River flows, in order to make useful predictions about future water apportionment; the famous inability of squabbling states to rationally divvy-up Colorado River water, resulting in protracted litigation that continues to this day; the failure of nascent environmental groups at mid-century to foresee the ecological effects of filling Glen Canyon; the ridiculous, internecine skirmishes between the National Park Service and the Bureau of Reclamation about potential dam sites; and the overarching failure of local, state and federal governments to understand that population growth in the West must be limited, or, to put it differently, that such growth must be commensurate with the limitations imposed by the environment. The list could go on. Fortunately, James Powell writes with such clarity, verve and attention to detail that even the arcane infighting of bureaucrats becomes interesting, in large measure because Powell keeps the reality of the Colorado River system at the forefront of his narrative. Fortunately, too, Dead Pool is not simply about Glen Canyon Dam and Lake Powell. It is also about how nature and culture have become intertwined in ways that make them difficult to tease apart, with the Colorado River system as a striking example, and global warming as a looming threat. Rising temperatures mean, among other things, reduced runoff for the Colorado River, perhaps by as much as 20 percent by 2050. The political problem is that states in the Upper Basin of the Colorado River drainage are obligated to release 8.23 million acre feet of water each year to the Lower Basin states through Glen Canyon Dam. But, if Lake Powell cannot continue to be filled, it will have to be drained to meet that obligation. As the lake lowers it eventually reaches the level of the dam’s lowest outlet—the level which provides the title for Powell’s book. Dead Pool is also about successes, although these are clearly limited in scope and, ultimately, flawed: engineering success in the form of an impressive dam built in a difficult environment; political success in the form of outmaneuvering one’s opponents, in order to provide the funding and the bureaucratic

NEW STRATEGIES TO ACHIEVE EFFICIENT WATER USE BY NEW BUSINESSES

The East Bay Municipal Utility District (EBMUD) provides approximately 225,000 acre feet of water per year to 1.3 million people and 22,000 commercial, institutional and industrial accounts near San Francisco Bay, California. As part of its aggressive demand management program, EBMUD offers business customers on-site inspections and financial assistance to convert existing water using equipment and processes to more water efficient technology. EBMUD would like to:Interact with sponsors of new commercial sites before construction begins.Employ high efficiency water use technology at the beginning of the business operation rather than retrofitting equipment at a later date.Benefit the customer by improving production output while reducing operating costs involving water, sewerage and energy.Make more effective use of EBMUD rate payer dollars. This new approach is called: WaterSmart Guidelines for New Business and includes:A guidebook describing updated water efficient technology for fourteen water using technologies employed in twenty types of business operationsTechnical requirements and recommendations regarding water efficiency for designers of new business facilitiesChecklists of water efficiency measures to be used by officials considering new applications for water service.A marketing plan to reach prospective business customers

Downstream hydrologic and geomorphic effects of large dams on American rivers

The hydrology and geomorphology of large rivers in America reflect the pervasive influence of an extensive water control infrastructure including more than 75,000 dams. One hundred thirty-seven of the very large dams, each storing 1.2 km 3 (10 6 acre feet) of water or more, alter the flows of every large river in the country. The hydrologic effects of these very large dams emerge from an analysis of the stream gage records of 72 river reaches organized into 36 pairs. One member of each pair is an unregulated reach above a dam, whereas the other is a regulated reach downstream from the same structure. Comparison of the regulated and unregulated reaches shows that very large dams, on average, reduce annual peak discharges 67% (in some individual cases up to 90%), decrease the ratio of annual maximum/mean flow 60%, decrease the range of daily discharges 64%, increase the number of reversals in discharge by 34%, and reduce the daily rates of ramping as much as 60%. Dams alter the timing of high and low flows and change the timing of the yearly maximum and minimum flows, in some cases by as much as half a year. Regional variation in rivers, dams, and responses are substantial: rivers in the Great Plains and Ozark/Ouachita regions have annual maximum/mean flow ratios that are 7 times greater than ratios for rivers in the Pacific Northwest. At the same time, the ratio of storage capacity/mean annual water yield for dams is greatest for Interior Western, Ozark/Ouachita and Great Plains rivers and least for Pacific Northwest streams. Thus, in many cases those rivers with the highest annual variability have the greatest potential impact from dams because structures can exert substantial control over downstream hydrology. The hydrologic changes by dams have fostered dramatic geomorphic differences between regulated and unregulated reaches. When compared to similar unregulated reaches, regulated reaches have 32% larger low flow channels, 50% smaller high flow channels, 79% less active flood plain area, and 3.6 times more inactive flood plain area. Dams also affect the area of active areas, the functional surfaces that are functionally connected to the present regime of the river. Regulated reaches have active areas that are 72 smaller than the active areas of similar unregulated reaches. The geomorphic complexity (number of separate functional surfaces per unit of channel length) is 37% less in regulated reaches. Reductions in the size of hydrologically active functional surfaces are greatest in rivers in the Great Plains and least in Eastern streams. The largest differences in geomorphic complexity are in interior western rivers. The shrunken, simplified geomorphology of regulated large rivers has had direct effects on riparian ecology, producing spatially smaller, less diverse riparian ecosystems compared to the larger, more complex ecosystems along unregulated reaches of rivers.

(308) The Mesa County Colorado Irrigation Audit Program

Seven and one-half square miles, or 4864 acres, of the Grand Valley in Western Colorado consists of high water-using landscapes. Overirrigation of Grand Valley soils flushes 580,000 tons of salt into the Colorado River each year. These salts negatively impact plant and animal health throughout the Colorado River basin. Proper watering of lawns can significantly reduce this problem. Correcting problems with a sprinkler irrigation system can reduce water use by an average of 40%. If water use on all 4864 acres was reduced by 40%, a savings of 11,187 acre feet, or over 3.6 billion gallons, of water would result. The annual historical evapotranspiration (ET) rate for the Grand Valley of Western is ≈61 inches; the ET rate during the irrigation season (April through October) is ≈49 inches. Since a typical sprinkler system is ≈70% efficient, in order to apply 49 inches of water to the soil, ≈70 inches of water is required. Irrigation system problems such as improperly spaced heads, sunken heads and heads not adjusted are typically responsible for 40% more water being applied than necessary. In Western Colorado, this equates to an over-application of 28 inches (2.3 acre feet) of water being applied each year. The 2005 Western Colorado irrigation audit problem covering 18.7 acres of turf. Assuming the problems noted were all corrected, a water savings of 43 acre feet, or 14,013,797 gallons, of water resulted. The 2006 audit program will continue this educational and water-saving effort. A grant from the Department of the Interior-Bureau of Reclamation will help fund the 2006 Irrigation Audit project.