Vol. 9, No. 1
New approaches to urban water management can result in greater water-use
efficiency and environmental benefits. Communities have begun using focused
recharge of urban stormwater to replenish the aquifer and offset consumption.
Use of drywells and pervious pavement are other means of capturing
stormwater and directing it to the subsurface. Treated wastewater is becoming
a larger component of municipal water supplies. The need to reserve
some water resources for water features and urban waterways is gradually
being recognized. But as these articles illustrate, urban water also presents
significant management challenges, ranging from water-quality concerns and
technological limitations to the impacts of considerable sociodemographic and
topographic differences within a single metropolitan region.
Vol. 8, No. 6
Water conservation is usually the first option utilities turn to when supplies suddenly run short. Increasingly, utilities are turning to conservation not just to survive short-term drought, but as a means to increase overall efficiency of water use; the saved water is a “new” supply for the future. But to effectively include conserved water as part of their water portfolios, providers must be able to quantify the savings, identify where additional savings might be achieved, and understand why some programs don’t catch on. This issue’s features consider existing and potential savings in a variety of sectors, as well as means to quantify savings and design effective savings-measurement programs.
Vol. 8, No. 5
The supercritical state of CO2 in the subsurface has fluid-like behavior, thus many aspects of hydrology apply to its sequestration. A good candidate storage site, often identified with the help of multi-phase flow modeling, has sufficient porosity to accommodate the volumes of CO2 being injected and low-permeability caprock to prevent its escape. Monitoring through wells, geophysics, and surface measurements is used to determine if any leakage is occurring. If CO2 does escape, it could reach drinking-water aquifers and impact water quality, or it could migrate to the surface, thereby defeating the purpose of sequestration. Regulations to minimize the risks of CO2 sequestration are in development, and pilot projects to test the process are underway across the country, including in the Southwest.
Vol. 8, No. 4
Nitrate is one of the most common groundwater contaminants worldwide, primarily caused by agriculture, leaking sewer systems, and septic systems. While some subsurface conditions naturally attenuate nitrate, the coarse-grained, oxygen-rich aquifers common in the Southwest favor its persistence. Thus we have a problem, and it is growing because the usual response has been to find a new water source rather than remediate the existing one. However, the tide is starting to change as fewer new water sources are available, impacts can no longer be ignored, and treatment technologies improve. These feature articles provide the details.
Vol. 8, No. 3
A 2008 article in Science declared, “Stationarity is dead.” Our water management systems are predicated on the assumption that natural systems vary within a relatively fixed range defined by historic records. But, as the article’s authors argue, the range is no longer stationary: climate change is breaking records and moving boundaries. Rising temperatures and new precipitation patterns will impact water supplies in the future, but the timing and amount of these impacts remain uncertain. How can we manage our water beyond stationarity? Articles in this issue explain how climate change projections are evaluated by experts worldwide, why model results can differ widely, and how those results are being reconciled. Information on future uncertainties and examples of transferable strategies for coping with change are offered.
Vol. 8, No. 2
Watershed management—managing resources on a watershed scale—is a challenge: watersheds cover large areas; have a variety of climates, species, and ecosystems; and have many different stakeholders. However, water managers are increasingly realizing the importance of looking at watersheds holistically to understand the interrelationships among their components before taking management actions. In this issue, we consider managing fire (prescribed and post-wildfire), forest thinning, and various restoration approaches, and how they contribute to the long-term resiliency of a watershed.
Vol. 8, No. 1
January 2009 brings the inauguration of a new President and many new members of Congress. They and the continuing members of Congress will need to address serious water issues facing the country, especially in the West. Infrastructure is crumbling. Water quality is becoming worse in many areas. Climate change is impacting our hydrologic systems in completely new ways. We must conserve more water, and we must act sooner rather than later. Several of the country’s foremost water experts share their thoughts on how the federal government could most efficiently and effectively face this imminent threat to our health, welfare, economy, and national security.
Vol. 7, No. 6
Groundwater was involved in the formation of many large uranium ore deposits, and increasingly groundwater (fortified with other compounds) is being used to mine them using in-situ leaching methods. Uranium mining in the 20th century left a legacy of surface water and groundwater contamination that is still being dealt with today. Water quality standards for uranium were not enacted until after mining began, which means insufficient or no background data were collected to serve as baseline remediation goals. Love it or hate it (there doesn’t appear to be a middle ground), uranium mining is on the increase in the Southwest.
Vol. 7, No. 5
The 1902 Reclamation Act set the stage for western development by facilitating the construction of large water transfer projects. The Central Valley Project, Colorado-Big Thompson Project, Colorado River Aqueduct, and many others moved water into the deserts and cities far from its original basins in the subsequent decades. The projects generally have performed as designed and will likely continue to do so in the future. But changing climate, environmental values, and demographics can present serious challenges to their operations, as the feature articles describe.
Vol. 7, No. 4
The Endangered Species Act (ESA) is increasingly forcing water managers to maintain a quantity and quality of water suitable for certain species and their habitats. This raises a number of challenges, not the least of which is determining how much water a species or habitat actually needs. In many situations, conflicts between ESA and other laws means that the loss of some species or habitat is unavoidable, but ESA has provisions for that too, such as restoring habitat or creating it elsewhere. ESA’s reach has extended far beyond species, however, in being a catalyst for developing water management plans for a wide variety of stakeholders, as illustrated in these feature articles.
Vol. 7, No. 3
In this issue we define the deliberate recharge and temporary storage of “excess” (unneeded) water in an aquifer, with the intent of recovering that water for future use, as aquifer storage and recovery (ASR). The technique is increasingly being used as a water management tool. The implementation of ASR projects varies widely in the type of water used, method of recharge, aquifer type, and engineering of the project, as described in these feature articles. Furthermore, water quality changes resulting from mixing two different waters must be considered, as well as regulatory and policy constraints. And do you really get that water back? Read all about it…
Vol. 7, No. 2
Salinity levels are creeping up in our fresh water, groundwater, and surface water. High salinity reduces crop productivity, corrodes machinery and pipes, and harms wildlife, not to mention that it tastes bad and may raise blood pressure. Is desalination the solution? Perhaps, at least for municipal and industrial use, but it’s too expensive for farmers and won’t help the fish in the rivers. And its waste stream must be dealt with… Read about how salts enter our waters, and how various groups are attempting to manage salinity either by preventing this intrusion or by removing and disposing of the salt once it is already present.
Vol. 7, No. 1
With all the sunshine and warm temperatures we have in the Southwest, we have the potential for very high rates of evapotranspiration—if water is available. The question is how much ET actually occurs? ET is a difficult parameter to measure, but various methods have been developed to try to get at that upward flux of moisture. These range from direct measurement at a single point to direct measurement from space, or indirect measurement at an equally large range of scales. Who is using these methods? For what uses? What sorts of values are being measured? Our contributors address these questions and more.
Vol. 6, No. 6
Invasive species invade: therein lies the problem. Floating and submerged plants such as hydrilla, water lettuce, water hyacinth, and giant salvinia form dense mats that literally cover waterways, shutting out light and restricting flow. Giant reed obstructs flood flows, crowds channels, consumes three times the water of native vegetation, and spreads fire. Saltcedar thrives at the expense of native cottonwood and willow in the Southwest, particularly in the many riparian environments that have been affected by human activity. The newest arrival to the area, the quagga mussel, hasn’t taken over yet, but wildlife managers and water providers need only look at the problems this mollusk has caused in the Great Lakes region to know what may await them. With all of these invaders, we’re not likely to be able to get rid of them. The best we can hope for is to manage our ecosystems to keep the populations of newcomers in line with other species.
Vol. 6, No. 5
Moving and treating water consumes energy, and producing energy nearly always consumes water: the two are tightly linked. The good news is that conservation of one results in savings of the other as well. By understanding how much water is required to produce various kinds of energy, we can move toward more water-efficient energy production. In turn, recognizing how much energy is needed for various components of our water systems will help us identify opportunities for greater efficiency. This issue’s articles look at both sides.
Vol. 6, No. 4
What is the source of perchlorate in a groundwater basin? Who released gasoline into an aquifer? What makes one river’s water so saline? Where does the water that supplies a riparian area originate? Forensic hydrology applies to both groundwater and surface water, and to water quality and quantity issues. A number of hydrologic “tools” are available to help provide answers. Isotopic analyses offer insight to a variety of investigations, as described in several articles. Standard geochemical analyses, microbial source tracking, aerial photos, and other methods can contribute valuable information, too. The key is to match the right tool or combination of tools to the situation to avoid ambiguous results. And, should you find yourself invited to a courthouse, insights from our authors could help you prepare.
Vol. 6, No. 3
In this preview of our first regional symposium, we consider some of the tough questions facing scientists, planners, and policy makers: Do our water policies reflect the actual physical limits of our water resources? How tightly are growth and energy consumption tied to water demand? How can we sustain our ecosystems, knowing today’s activities may not impact the hydrologic system for decades? How can we grow differently? Only by answering questions such as these can we try to accommodate the interests of the economy and the environment, and still have a place we want to live in.
Vol. 6, No. 2
As western water managers look for ways to diversify their water portfolios, they’re increasingly looking up to the clouds, wondering if they can squeeze any additional water from them. Is cloud seeding a viable new source of water for the West? Perhaps. Under certain conditions, microscopic-sized materials injected into clouds can cause more precipitation to occur than would have fallen naturally. But many questions remain regarding the details of the process, the success of programs, and the impacts of air pollution. Such questions have held up federal funding of research programs, but some local groups are proceeding on their own.
Vol. 6, No. 1
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…
Vol. 5, No. 6
Chemical disinfection of drinking water is arguably one of the greatest advances in human health. However, nothing is perfect. The byproducts that form when disinfectants combine with otherwise harmless compounds in water warrant our attention. Although the carcinogenic nature of some disinfection byproducts (DBPs) was first shown in the 1970s, only a few of the hundreds that have been identified are regulated. What are DBPs? How and where do they form, and how do utilities manage them? How do recent stricter compliance standards affect utilities? What is known about other DBPs besides the few that are federally regulated? And what is the fate of DBPs in the subsurface when treated water is used as recharge water to replenish aquifers? This issue’s feature articles help answer such questions.
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Vol. 5, No. 5
Water issues in the rural Southwest are growing along with the population, and this issue of Southwest Hydrology looks at the unique water challenges faced by rural communities. In the area of water resources, feature articles address funding and leadership challenges in rural communities, the effects of Arizona’s legislation on protecting rural water supplies, and movement in New Mexico toward regionalization (or simply banding together). In the water quality arena, the articles cover the impacts of the new arsenic standard on small providers, the contaminants that are showing up in individual and small system wells, and efforts to help farmers in rural California protect their groundwater.
Vol. 5, No. 4
Decision support systems (DSSs) can range from a basic flow chart or stack of GIS layers to a complex computer model that incorporates physical, economic, cultural, and regulatory attributes to evaluate any number of scenarios. Here, we focus on understanding how the more complex type of DSSs work, and how, where, and by whom they are being used to make water management decisions. As illustrated in several articles, one of the strengths of DSSs is their ability to allow stakeholders to “test” the effects of various management alternatives, which helps them better understand the processes and interactions that occur in the system.
Vol. 5, No. 3
“We need more data.” Water professionals seemingly always wish for more data, which may ultimately lead to better-informed decisions. But simply improving access to and management of existing data can make a difference. In this issue, we consider large-scale hydrologic data collection programs, the importance of having sufficient data to ably manage our water resources, and the importance of providing context to data. We also look into the financial struggles of federal long-term hydrologic data collection programs. Finally, we include examples of data management schemes from national to local levels, and tips to improve data management.
Vol. 5, No. 2
Today’s typical municipal water infrastructure includes a patchwork of smaller systems built by other entities and subsequently acquired by the utility. Many are very old, built with no or inferior standards. California’s extensive levee system was developed similarly. Most of our big dams are now 50 to 100 years old. Our water infrastructure is starting to crumble. Often, funds are insufficient for even routine maintenance, so utilities and relief agencies can only respond to disasters as they happen. And we can expect more disasters if the situation is not addressed. In this issue we take a realistic look at the problem, what can be done, and how much it might cost.
Vol. 5, No. 1
The concept of using constructed wetlands for water treatment arose from observations of natural wetlands’ ability to remove contaminants from the watershed. In both systems, biological, physical, and chemical processes that reduce contaminants occur—including settling, microbial oxidation, anaerobic decomposition, denitrification, adsorption, and precipitation. This issue’s feature articles describe a broad range of contaminants being treated by constructed wetlands, the suitability of different types of wetlands for different situations, and, importantly for both public relations and public health, how to keep the mosquitoes at bay.
Vol. 4, No. 6
The production of oil and gas is big business in the West, and with that production comes water—at times more water than fuel. Producers spend large sums to dispose of this “produced” water, usually by injecting it into deep-aquifer wells. But some of the highestproducing states—Texas, New Mexico, Colorado, California, Wyoming, and Montana—have been scrambling to find water supplies for their future. Is the solution obvious? This issue’s feature articles indicate it’s not so simple. While water quality varies from one production field to another, most produced water requires some kind of treatment before it can be used beneficially. Regulatory and ownership issues must also be considered. In some areas, however, industry, communities, and agencies have jointly found ways to put the resource to use. The quantities may not be sufficient to solve all our water problems, but produced water could become one more asset in our water resources portfolio.
Vol. 4, No. 5
While rivers and other water bodies often influence the drawing of political boundaries, the laws of hydrology do not heed such limits. Water quality and quantity issues, related to both groundwater and surface water, extend across the U.S./Mexico border, and are exacerbated by growing populations and drought. Groups from both sides have been working together at local, state, and federal levels to address these issues. From sharing data, to establishing monitoring programs, creating management plans, donating equipment, and training workers, this issue’s feature articles illustrate many examples of cross-border collaboration.
Vol. 4, No. 4
Agriculture accounts for the greatest single water use in the Southwest. Demands for water by growing urban areas, environmental and recreational interests, and industries, combined with many recent years of drought, create competition for water that is greater than ever. How are farmers coping? New technologies allow improved efficiency in irritation and for moving water through irrigation districts, but salinity remains a growing problem. Higher-valued crops are being planted to offset increased water and monitoring costs. The ag-to-urban movement impacts not just our food supply, but also our water supply. Our feature articles discuss these and other aspects of agriculture in the 21st century.
Vol. 4, No. 3
Remotely sensed data acquired by satellites and aircraft are being used by water resources professionals at scales ranging from two feet to many square miles. What parameters are being measured? How are the data obtained? What sort of data processing is required? What accuracy is attainable? How are these techniques being applied? Read on to find out…
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Vol. 4, No. 2
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.
Vol. 4, No. 1
Our population is growing. We’re in a drought. Water supplies are dwindling. If water were plentiful for all people and ecosystems, sustainability would not be the hot issue it is. But we live in an era of limits, and water resources are among the shortest resources in supply. Our groundwater reserves are being mined. Management for sustainable water resources calls for using our water resources to address present needs without compromising future needs. But do we really know when and how the impacts of our activities on water resources today will be felt in the future? Do we know what future needs, values, and supplies will be? How can we best manage for now and the future? Adaptive management may be the best approach we have, but it doesn’t solve everything. Our articles explain…
Vol. 3, No. 6
Given the many developments in water treatment technology over the past century, it may seem surprising that microorganisms have been the cause of more than 75 percent of all waterborne illnesses associated with drinking water in the past 20 years and that outbreaks have more than doubled in the past few years. Are the pathogens also getting more sophisticated? Perhaps not, but new ones do continue to emerge for a variety of reasons. And they present challenges that chemical contaminants do not. For example, they require a human to identify them, and if only a few pass through the water treatment system, they can flourish under the right conditions. In this issue, we look at the major groups of pathogens, how they are detected and treated, and how their abundance varies spatially and temporally in surface waters and groundwaters.
Vol. 3, No. 5
In recent years, wildfires have burned thousands of square miles of the Southwest, with wide-ranging consequences to hydrologic systems. In this issue, we consider the effects of fire on soils, stream discharge, and water quality, including the extent and duration of impacts. In addition, we review watershed rehabilitation and emergency treatment practices currently in use, and look at one city’s evaluation of its pre-fire management alternatives.
Vol. 3, No. 4
Terminal lakes present a unique management challenge because of the very nature of their hydrologic systems: they lie at the lowest point of the basin, and the only way water can leave is through evaporation. Activities upstream of terminal lakes, including input of salts and contaminants as well as diversions for agriculture and cities, all impact the lake, and ecological systems bear the consequences. Here we look at the management – and mismanagement – histories of several terminal lakes, to see what’s been learned.
Vol. 3, No. 3
A geographic information system (GIS) is a system of computer software, hardware, and data used to manipulate, analyze, and present information tied to a spatial location. Once the domain of highly trained computer graphics specialists, GIS use has rapidly become widespread among hydrologists in recent years due to improved, user-friendly software, a dramatic increase in the availability of data, and the identification of new applications for which GIS is suited. Our articles present the current state and future directions of GIS in hydrology.
Vol. 3, No. 2
Ongoing drought and a rapidly growing population in the naturally dry climate of the Southwest have created a high demand for scarce water. With this increased demand for a limited resource comes a need to understand the economics of water, not just the science of it. Water has traditionally been treated as a public good, but in areas where it is increasingly scarce, it is becoming a tradable commodity through the development of water markets. In this issue’s feature articles, we look at when, where, and why water may be a commodity, and how water markets work.
Vol. 3, No. 1
The Colorado River Delta covered roughly two million acres of riparian corridors and wetlands when the Europeans first arrived in the area in the 1500s. Dam construction on the river that began in the 1930s and lasted for four decades severely reduced and frequently cut off altogether the flow into the delta during that time. Today the delta covers only about 420,000 acres, but it remains an ecological oasis rich in biodiversity, providing habitat to more than 350 species of birds. Increased river flow in recent decades has helped the ecosystem to recover somewhat; management decisions made now will determine its future. Our feature authors look at the changes in streamflow and riparian habitat over the decades, water quality, water management, and cross-border and grass-roots restoration activities in the delta.
Vol. 2, No. 6
“Pharmaceuticals and personal care products” (PPCPs) and “endocrine-disrupting compounds” (EDCs) are as hard to say as one might think they are to drink. Recent developments in analytical techniques have allowed researchers to detect the presence of dozens of these compounds in wastewater-affected streams and in groundwater, at concentrations in the nanograms per liter range. Now that we have an idea of what compounds are present, there is much to learn about how long they persist, where they go, and what the implications are to ecosystems and human health.
Vol. 2, No. 5
Remote water resource monitoring systems are now being used in applications as simple as monitoring soil moisture at a golf course to as complex as multi-sensored systems that provide snow melt, stream discharge, reservoir level, meteorological, and water quality data in order to adjust flow through a regional water distribution system. Recent advances in sensor and data transmission technologies have made these systems more feasible than ever. Furthermore, Internet capabilities allow widespread access to the data. Our feature authors discuss various kinds of remote monitoring systems and their applications.
Vol. 2, No. 4
The “Law of the Biggest Pump” or laws for managed pumping? Water for the “first in time” or water for the streams? Can historic precedent be overruled? And, can “hydrologic reality” be legislated? This issue’s authors take a look at how surface water and groundwater are managed in the states of the Southwest, and more importantly, how historic precedent is slowly giving way to the technical realities of our greatest resource.
Vol. 2, No. 3
As local water supplies become depleted and demand for water in the Southwest continues to rise, municipalities have begun considering other sources of water – brackish groundwater, recycled water, and seawater, made potable through desalination. The cost of desalination technology has come down in recent years, although it is still not competitive with treatment of fresh water. However, when local freshwater sources are no longer available and the costs of importing water are factored in, desalination may become economically feasible in some areas. Several desalination plants were built in the Southwest in the early 1990s, but an end to the drought that prevailed at that time resulted in those plants having never been used. Given the current drought, as well as an increased demand for water resources, their operation is again being considered, and many more are in the planning or construction phase.
Vol. 2, No. 2
An array of natural and human-generated processes can degrade the proper functioning of Southwestern riparian areas. A range of disturbances can affect these desert oases from the sub-alpine headwaters to flowing desert bosques. To manage, protect, or repair riparian systems that are in decline, we need to fully understand the causes and effects of the changes we have made throughout the entire watershed. Several experts share their thoughts on what has gone wrong, and what might be done to reverse the decline of riparian areas.
Vol. 2, No. 1
Isotopes can be powerful tools in the field of hydrology, able to provide definitive answers to questions of recharge and flowpaths that many thousands of dollars’ worth of aquifer tests, new boreholes, and models may not. But what are isotopes, really, and how does one begin to figure out which ones could be applied in a particular setting? Several experts in the field discuss interpretation, analyses, and costs, and present case studies to illustrate how they have been applied successfully in Southwest basins. And, if you want to learn more, we provide the references to take you further.
Vol. 1, No. 4
Natural Resource Damage Assessments of injuries to surface and ground water resources is expanding throughout the United States. In the Southwest, where water is scarce, precious to humans and the environment, and in many areas is depleted faster than it is replenished, the value of water is steadily increasing. As a result, NRDA claims for injury to water resources can mean big business to resource trustees and big losses to those responsible. The largest NRDA claim is currently underway in Albuquerque, New Mexico, where the resource trustees have valued the allegedly injured water resource at $4 billion. In this issue our authors explore the basis for NRDAs and offer creative, lower-cost solutions.
– Steven I. Michelson, R.G., MECA
Vol. 1, No. 3
If you ever have the opportunity to visit a world-class, open-pit mine, do it. Whether horrified or proud, there’s no substitute for looking into a 1,500-foot deep, two-mile long, man-made abyss to grasp the magnitude of human industriousness. Most of the large mines extend below the water table and will eventually fill with groundwater to form pit lakes. About forty pit lakes are expected to form in Nevada, predicted to range in size from mere puddles up to 400,000 acre-feet; and there may be another couple dozen that will form in other states across the Southwest. If you believe the groundwater models, most of these will be terminal basins – net sinks that pull in groundwater from all sides, evaporatively concentrating solutes in the lake. No need to rush, of course, because these pit lakes are expected to remain for thousands of years. This, of course, is the problem.
– Houston Kempton, Integral Consulting, Inc., Boulder, CO
Vol. 1, No. 2
“Drought” is all over the headlines these days. But what constitutes a drought? What is “average?” Are we being short-sighted by basing our policies and actions on conditions that have occurred in our lifetime? Whether we react to weather or plan for climate depends not only on how well we understand past climate, but also on how well we can predict future climate. Do agencies and industry incorporate climate variability data in their current operations? Should they? We asked several authorities who work with climate on a daily basis to address these issues.
Vol. 1, No. 1
The EPA’s reduction of the Maximum Contaminant Level for arsenic in drinking water to 10 parts per billion (ppb) has caused a storm among those charged with providing safe drinking water. System managers are faced with treating water they previously thought to be of good quality, or perhaps shutting off wells altogether. Consultants and engineers are largely unprepared to offer cost-effective remedial solutions to either small or large providers. Agencies are just beginning to talk about strategies to implement and monitor the strict new rule. States have not determined where the money for these changes will come from, or even if it is available. We present six articles to review the current state of affairs.