WATER SUPPLY OPTIONS IN A NEW MEXICO WATER PLANNING REGION1

ABSTRACT: The population in the Jemez y Sangre Water Planning Region of New Mexico has reached the point at which the demand for water exceeds available supplies, particularly when precipitation is below average, as has frequently occurred in recent years. The desire to develop a sustainable water supply that relies on renewable supplies in wet years and preserves the water in storage for times of drought motivated a diverse set of stakeholders in the region to participate in regional water planning. The planning effort culminated in development of the Jemez y Sangre Regional Water Plan, which was adopted by municipal and county governments in the region. The plan assesses and compares water supply and demand in the region and recommends alternatives for protecting and restoring the existing water supply and addressing the pending gap between supply and demand anticipated by the year 2060. To convey to decision makers the alternatives available to solve the future water shortage, option charts were developed to portray the amount of water that could be obtained or conserved through their implementation. The option charts show that the projected gap between supply and demand cannot be met through one alternative only, but will require a combination of alternatives.     

Impacts of Multiple Stresses on Water Demand and Supply Across the Southeastern United States1

Abstract: Assessment of long‐term impacts of projected changes in climate, population, and land use and land cover on regional water resource is critical to the sustainable development of the southeastern United States. The objective of this study was to fully budget annual water availability for water supply (precipitation ? evapotranspiration + groundwater supply + return flow) and demand from commercial, domestic, industrial, irrigation, livestock, mining, and thermoelectric uses. The Water Supply Stress Index and Water Supply Stress Index Ratio were developed to evaluate water stress conditions over time and across the 666 eight‐digit Hydrologic Unit Code basins in the 13 southeastern states. Predictions from two Global Circulation Models (CGC1 and HadCM2Sul), one land use change model, and one human population model, were integrated to project future water supply stress in 2020. We found that population increase greatly stressed water supply in metropolitan areas located in the Piedmont region and Florida. Predicted land use and land cover changes will have little effect on water quantity and water supply‐water demand relationship. In contrast, climate changes had the most pronounced effects on regional water supply and demand, especially in western Texas where water stress was historically highest in the study region. The simulation system developed by this study is useful for water resource planners to address water shortage problems such as those experienced during 2007 in the study region. Future studies should focus on refining the water supply term to include flow exchanges between watersheds and constraints of water quality and environmental flows to water availability for human use.     

A SURVEY OF STATE WATER CONSERVATION PROGRAMS IN THE U.S.1

ABSTRACT: Adequate water supplies are critical to the maintenance of a community's health and economic well-being. Across the nation communities are struggling to meet an expanding demand for water from municipal, industrial, agricultural, recreation, water quality, and power generation users. As the demand grows and communities actively compete with one another for a limited water supply, states are being called upon to help solve the problem. One possible solution that is being used in many areas is the development and implementation of a water conservation program to stretch the limited supply as far as possible. using a mailed survey, state water conservation programs and some of the characteristics of the different programs were documented. Responses to the nationwide survey were obtained from all 50 states. The specific water conservation program elements on which information was received from the survey included laws and restricted use, community assistance, education, research, and other services. Recommendations for states developing or considering the development of a water conservation program are outlined.     

SIMULATING FLOW IN REGIONAL WETLANDS WITH THE MODFLOW WETLANDS PACKAGE1

ABSTRACT: As part of the Comprehensive Everglades Restoration Plan (CERP), various water supply projects have been proposed in a region located between the Miami metropolitan area and the extensive regional wetland systems that are part of the Everglades or remnant Everglades. A ground water flow model of the surficial aquifer within northern Miami‐Dade County was constructed using MODFLOW to evaluate the effects of these projects on water levels in the wetlands and the underlying surficial aquifer. The new Wetlands package was used to conjunctively simulate overland flow through these wetlands and the shallow ground water system. Comparisons of simulated to measured ground water levels and wetland stages were very satisfactory, where computed and measured water levels agreed within 0.5 ft over most of the period of record at nearly all of the monitoring sites. Temporal trends in water levels were also replicated. It was concluded that the assumptions and methodologies inherent to the Wetlands package were suitable for simulating regional wetland hydrology within the Everglades area.     

WATER SUPPLY AND URBAN GROWTH PLANNING: A PARTNERSHIP1

ABSTRACT As urban expansion outstrips water supplies, the usual solution is to build pipelines to bring in water from sources farther afield. Such water supplies may act as either a leader of urban development or as a follower. In either case, this engineering approach to the provision of water has fostered less than optimal utilization of regional water and land resources for urban growth. More efficient utilization of these resources is achieved when water supply development and urban growth planning are conjoint activities. Water supply planners and land use planners, working together, are able to generate and evaluate the full range of urban development options, including water demand management through conservation. Preferred regional growth plans are achieved using the best mix of water supply and urban growth. The result is a reduced rate of water supply development and a reduction of urban expansion on prime lands. This partnership approach is demonstrated for the Calgary Region under two levels of water conservation.     

RATES,RIGHTS, AND REGIONAL PLANNING IN THE METROPOLITAN WATER DISTRICT OF SOUTHERN CALIFORNIA1

ABSTRACT: The Metropolitan Water District of Southern California has for more than 70 years shaped the development of an immense urban region. The district's current strategic planning process therefore could have substantial effects on regional water planning and management. The rate restructuring phase of the planning process has produced a multiple component, cost of service based framework. This paper describes that framework as well as some criticisms that have been directed toward it. The rate restructuring was shaped, and for a while stalled, by old disputes among member agencies over rights to water supplied by Metropolitan. That controversy has diverted attention from the resource management implications of the rate structure. This paper presents an alternative future focused approach to regional integrated water resource planning for Southern California based on projections of current trends and anticipation of future events. This discussion raises the question of how regional integrated water resources planning of this sort may proceed, and what role Metropolitan will play in that process.     

CONJUNCTIVE SURFACE AND GROUND WATER MANAGEMENT IN THE JAKARTA REGION,INDONESIA1

ABSTRACT: This study investigates the degree of economic inefficiency of the current institutional arrangements for surface and ground water management in meeting urban water demand in the Jakarta region. A numerical model of integrated surface and ground water management is developed using GAMS (General Algebraic Modelling System) software. The model maximizes the net present value of social benefits from piped water and ground water consumption across all users over time from 1999 to 2025. Four policy scenarios are examined: the status quo, the social planner's solution, and two ground water pumping quota scenarios: an aggregate ground water pumping quota and a partial quota applied to commercial and industrial users. Three variations in each policy scenario are considered: investment in water infrastructure of the Jakarta water enterprise (PAM Jaya), water demand growth, and discount rates. The status quo, depending on the investment option, the growth of water demand, and the discount rate, results in a 7.4 to 47.8 percent loss in economic efficiency relative to the social planner's solution. The partial quota is the most feasible, applicable, and manageable scenario. The optimal investment option could increase the volume of piped water supply and reduce the cost of water production. The volume of water delivery could increase by up to 156 percent, but it implies only a 35 percent increase in the surface raw water demands above the current level. However, it does not significantly reduce cumulative ground water extraction over the time period considered.     

Integrated Modeling of Water Supply and Demand under Management Options and Climate Change Scenarios in Chifeng City,China

Water resource management is becoming increasingly challenging in northern China because of the rapid increase in water demand and decline in water supply due to climate change. We provide a case study demonstrating the importance of integrated watershed management in sustaining water resources in Chifeng City, northern China. We examine the consequences of various climate change scenarios and adaptive management options on water supply by integrating the Soil and Water Assessment Tool and Water Evaluation and Planning models. We show how integrated modeling is useful in projecting the likely effects of management options using limited information. Our study indicates that constructing more reservoirs can alleviate the current water shortage and groundwater depletion problems. However, this option is not necessarily the most effective measure to solve water supply problems; instead, improving irrigation efficiency and changing cropping structure may be more effective. Furthermore, measures to increase water supply have limited effects on water availability under a continuous drought and a dry‐and‐warm climate scenario. We conclude that the combined measure of reducing water demand and increasing supply is the most effective and practical solution for the water shortage problems in the study area.     

RISK IN IRRIGATION WATER SUPPLY AND THE EFFECTS ON FOOD PRODUCTION1

ABSTRACT: This paper examines irrigation water supply deficit and associated risk indicators due to random climate events and potential effects on irrigated food production during the period 1996 to 2025 for seven river basins in the USA, China, and India. An integrated water and food model with global scope is applied for the analysis. The global climate regime during 1961 to 1990 is used to generate 30 climatic scenarios for the time period 1996 to 2025, and these scenarios are applied to the model in order to characterize the randomness of precipitation, runoff, and evapotranspiration, which affects both irrigation water supply and demand. The risk with random climate events is represented by reliability, variability, and vulnerability from different perspectives. Regarding irrigation water supply, Colorado will bear an increasingly unstable situation although the average water supply relative to the demand will maintain at a relatively high level; selected basins in China and India indicate that significantly lower levels of reliability and more deleterious affects from drought can be expected, but under a less variable condition due to assumed water storage increase. From 1996 to 2025, the effects of water deficits on irrigated food production are characterized with a nonlinear phenomenon and food production loss will be more sensitive to irrigation water supply deficit in the future. Future work following this paper needs to consider the impact of global climate change and the water quality of the irrigation return flow and result verification by local studies.     

ANALYSIS OF FIRM WATER SUPPLY UNDER COMPLEX INSTITUTIONAL CONSTRAINTS1

River basin computer simulation studies often do not properly include the complex legal and institutional factors governing water allocation. These factors include formal water rights and informal borrowing agreements among the basin water users. An attempt has been made in this study to show that such factors can be included. We also show that an optimal, integrated approach to reservoir operations in a river basin can do much to alleviate the burden of new demands placed on available water resources. The procurement of a firm water supply for a proposed coal fired power plant is analyzed as a case study. An efficient river basin simulation model is used to determine the viability of a scheme for providing an annual firm water supply to the plant, with consideration of the existing water storage and demands within the basin. Given the hydrologic sequence considered, the model results show that the proposed strategy is viable in that the required firm water supply can be realized without causing harm to decreed water users in the basin. However, integrated diversion and reservoir operations are required to assure a desirable uniform rate of delivery of reusable effluent to the power plant.     

A Level‐of‐Service Concept for Planning Future Water Supply Projects under Probabilistic Demand and Supply Framework

One of the most challenging tasks of water supply utilities is planning the timing and quantity of new water supply sources as demand for water consumption grows. Many water supply utilities target on meeting 100% of their customers' needs based on scenario‐based deterministic demand projections numbers even though there are uncertainties in both supply and demand values. This may result in under or overly conservative approach in assessing future needs. In this article, a level‐of‐service concept is introduced to capture a utility's willingness to accept a given level of risk, plan for it, and invoke a management strategy during extreme events than build a facility to accommodate those in planning for new water supply sources. Accounting for uncertainties in both supply and demand help quantify reliability by achieving a prescribed level of service. The major benefit of such an approach for planning future water supply is that it allows policy makers to evaluate the use of adaptive water management strategies and develop supply in an incremental fashion as demand warrants it. For example, if a given level of service cannot be reliably met with the existing system at a future time t, an incremental water supply project would come online to bring the required reliability level up but no more.     

REGIONAL WATER SUPPLY PLANNING STUDY FOR NORTHEASTERN ILLINOIS1

ABSTRACT: The development of a regional water supply system for the six-county area of Northeastern Illinois is presented in this paper, including: 1) the establishment of regional water supply technical planning policies; 2) the development and utilization of a regional water supply computer model to identify the principal and secondary sources of water supply for each entity in the study area, based on an apparent cost-effective source analysis; and 3) utilization of the study results to develop for the year 2010 a suggested preliminary regional water supply system. Using the findings from task 2 above, a proposed plan for overall Lake Michigan water use through the year 2010 was also developed. The effects of the proposed regional water supply system on future water levels in the deep aquifer were also discussed.     

Water–energy–greenhouse gas nexus of urban water systems: Review of concepts,state-of-art and methods

Water supply and wastewater services incur a large amount of energy and GHG emissions. It is therefore imperative to understand the link between water and energy as their availability and demand are closely interrelated. This paper presents a literature review and assessment of knowledge gaps related to water–energy–greenhouse gas (GHG) nexus studies in an urban context from an ‘energy for water’ perspective. The review comprehensively surveyed various studies undertaken in various regions of the world and focusing on individual or multiple subsystems of an urban water system. The paper also analyses the energy intensity of decentralized water systems and various water end-uses together with the major tools and models used. A major gap identified from this review is the lack of a holistic and systematic framework to capture the dynamics of multiple water–energy–GHG linkages in an integrated urban water system where centralized and decentralized water systems are combined to meet increased water demand. Other knowledge gaps identified are the absence of studies, peer reviewed papers, data and information on water–energy interactions while adopting a ‘fit for purpose water strategy’ for water supply. Finally, based on this review, we propose a water–energy nexus framework to investigate ‘fit-for-purpose’ water strategy.     

Implications of Upstream Flow Availability for Watershed Surface Water Supply across the Conterminous United States

Although it is well established that the availability of upstream flow (AUF) affects downstream water supply, its significance has not been rigorously categorized and quantified at fine resolutions. This study aims to fill this gap by providing a nationwide inventory of AUF and local water resource, and assessing their roles in securing water supply across the 2,099 8‐digit hydrologic unit code watersheds in the conterminous United States (CONUS). We investigated the effects of river hydraulic connectivity, climate variability, and water withdrawal, and consumption on water availability and water stress (ratio of demand to supply) in the past three decades (i.e., 1981–2010). The results show that 12% of the CONUS land relied on AUF for adequate freshwater supply, while local water alone was sufficient to meet the demand in another 74% of the area. The remaining 14% highly stressed area was mostly found in headwater areas or watersheds that were isolated from other basins, where stress levels were more sensitive to climate variability. Although the constantly changing water demand was the primary cause of escalating/diminishing stress, AUF variation could be an important driver in the arid south and southwest. This research contributes to better understanding of the significance of upstream–downstream water nexus in regional water availability, and this becomes more crucial under a changing climate and with intensified human activities.     

WATER SHORTAGES,DEVELOPMENT, AND DROUGHT IN ROCKLAND COUNTY,NEW YORK1

Knowledge of the historical variability of regional climate is an essential element of successful water resource planning. Lacking such perspective, planners and managers can be deceived as to the severity of a recent climate extreme, such as drought, and place a disproportionate blame on the climate, not the integrity of the supply system should water restrictions become necessary to avoid shortages. Presented here is a vivid example of how development, a lack of adequate planning, and climate variability have converged to produce three water emergencies in Rockland County, New York, since 1995. An examination of climate data over the past century indicates that the severity of the recent droughts was well within the range of past variability. Rather than climate alone, the recent water emergencies have highlighted a significant mismatch between supply and demand that has been developing in Rockland County over the past three decades. Substantial development, largely in the form of single‐family homes, has not been matched with a corresponding enhancement of the county's water system. Realistic plans for meeting current water demand will require cooperation among all stakeholders, beginning with an acknowledgement that climate variations are inevitable, not the sole source of blame when water shortages arise.     

PUBLIC EXPENDITURE PROGRAMS IN APPALACHIA AND THEIR IMPACT ON REGIONAL EMPLOYMENT1

ABSTRACT: The reduction of regional unemployment requires a sufficient demand for regional labor and the demand pattern must parallel that of supply. Due to the interdependency of Appalachian economy with the rest of the Nation, the leakage of the final demand imposed on a subregion of Appalachia is substantial. The more capital intensive the investment the higher the leakage which will lead to less demand for labor in Appalachia. While water resource projects are generally longterm projects which aim at structural changes in a regional economy, consumption expenditures induced by welfare payments or public employment programs are basically temporary measures for the rescue of unemployment. Average consumption and private investment programs may impose on Appalachia a larger material demand but the demand for the total regional labor, off-site and on-site combined, is estimated to be less than that from water resource investments. The public expenditure program for combating regional unemployment must be discretionary based on its purpose and its potential to generate optimum demand for labor which will be created by the pattern of regional resource distribution and interindustrial and interregional interactions. An interregional I/O model is best suited for analysis of this type.     

THE ENHANCED ROLE OF WATER CONSERVATION IN THE COST-BENEFIT ANALYSIS OF WATER PROJECTS1

The concept of water conservation has increased in importance because of revisions in the rules and procedures for performing cost-benefit analyses of federal water projects. These revisions include a requirement that nonstructural and water conservation measures be incorporated into economic assessments of projects. Project analyses will now proceed as if water supplies were allocated “most effectively,” that is, to their highest valued uses. A related requirement provides that the net benefits of any project should now be valued using willingness to pay measures. A specific cost-benefit methodology accommodating the revisions is constructed and discussed. Informational requirements for applying this methodology are identified. In addition to being consistent with federal mandates, this technique offers important advantages over the traditional “requirements” approach to water supply planning.     

Water Supply Planning Considering Uncertainties in Future Water Demand and Climate: A Case Study in an Illinois Watershed

Ensuring an adequate, reliable, clean, and affordable water supply for citizens and industries requires informed, long-range water supply planning, which is critically important for water security. A balance between water supply and demand must be considered for a long-term plan. However, water demand projections are often highly uncertain. Climate change could impact the hydrologic processes, and consequently, threaten water supply. Thus, understanding the uncertainties in future water demand and climate is critical for developing a sound water supply plan. In Illinois, regional water supply planning attempts to explore the impacts of future water demand and climate on water supply using scenario analyses and hydrologic modeling. This study is aimed at developing a water supply planning framework that considers both future water demand and climate change impacts. This framework is based on the Soil and Water Assessment Tool to simulate the watershed hydrology and conduct scenario analyses that consider the uncertainties in both future water demand and climate as well as their impacts on water supply. The framework was applied to water supply planning efforts in the Kankakee River watershed. The Kankakee River watershed model was calibrated and validated to observed streamflow records at four long-term United States Geological Survey streamflow gages. Because of the many model parameters involved, the calibration process was automated and was followed by a manual refinement, resulting in good model performance. Long-range water demand projections were prepared by the Illinois State Water Survey. Six future water demand scenarios were established based on a suite of assumptions. Climate scenarios were obtained from the Coupled Model Intercomparison Projection Phase 5 datasets. Three representative concentration pathways (RCPs), RCP2.6, RCP4.5, and RCP8.5, are used in the study. The scenario simulation results demonstrated that climate change appears to have a greater impact on water availability in the study area than water demand. The framework developed in this study can also be used to explore the impacts of uncertainties of water demand and climate on water supply and can be extended to other regions and watersheds.     

MUNICIPAL WATER USE AND WATER RATES DRIVEN BY SEVERE DROUGHT: A CASE STUDY1

ABSTRACT: This paper synthesizes and interprets data pertaining to the evolution of average water revenue, water use, and the average cost of water supply in the City of Santa Barbara, California, from 1986 to 1996, a period which included one of the most devastating droughts in California this century. The 1987–1992 drought hit the study area particularly hard. The City of Santa Barbara was dependent exclusively on local sources for its water supply. That made it vulnerable as the regional climate is prone to extreme variability and recurrent droughts. The 1986–1992 drought provided a rare opportunity to assess the sensitivity of municipal water use to pricing, conservation, and other water management measures under extreme drought conditions. Our analysis indicates that the average cost of water rose more than three-fold in real terms from 1986 to 1996, while the gap between the average cost of supply and the average revenue per unit of water (= 100 cubic feet) rose in real terms from $0.14 in 1986 to $ 0.75 in 1996. The rise of $3.08 in the average cost of supplying one unit of water between 1986 and 1996 measures the cost of hedging drought risk in the study area. Water use dropped 46 percent at the height of the drought relative to pro-drought water use, and remains at 61 percent of the pre-drought level. The data derived from the 1987–1992 California drought are unique and valuable insofar as shedding light on drought/water demand adaptive interactions. The experience garnered on drought management during that unique period points to the possibilities available for future water management in the Arid West where dwindling water supplies and burgeoning populations are facts that we must deal with.     

THE OPTIMAL TIME TO START THE OPERATION OF A DESALTING PLANT IN ISRAEL1

The study contains the methodology of finding the optimal time to start the operation of a desalting plant or any other non conventional source of water for agricultural use in Israel. The essence of the methodology is the moving equilibrium price and quantity of agricultural products. The market of agricultural products is represented by a single demand curve and a supply curve which is derived from the agricultural sector production function. Both the demand for and the supply of agricultural products functions are shifting over time. The marginal value product of water is the critical value that determines the optimal time of a desalting plant. The study is static in the sense that dynamic aspects per se are not dealt with-e.g. learning by doing of building and operating desalting plants. The empirical results although used for illustrative purposes can be used as reference points for other detailed and more ‘exact’ studies on water desalination.