Water Resources planning and management

This paper presents a technique to quantify water savings due to implementation of water restrictions by adopting water restriction indexes as a continuous numerical predictor variable in regression analysis. The adopted modeling technique compares four methods: yearly base difference method, weighted average method, before and after method, and expected use method. These methods are applied to single and multiple dwelling residential sectors in the Blue Mountains region, Australia. In the study, three forms of multiple regression techniques are adopted: raw data, semi-log, and log-log. The model performances are evaluated by a number of statistics such as relative error, Nash-Sutcliffe coefficient, and percentage bias. Moreover, the potential of using the water restriction savings and water conservation savings as continuous predictor variables in the water demand forecasting model is investigated. The performances of different modeling techniques are evaluated using split-sample and leave-one-out cross-validation methods. The yearly base difference method is found to quantify the water savings more accurately in that the savings due to Level 1, Level 2, and Level 3 water restrictions are found to be approximately 9, 18, and 20%, respectively, for the single dwelling residential sector and approximately 4, 8, and 9%, respectively, for the multiple dwelling residential sector. The semi-log model coupled with yearly base difference method is found to perform the best in predicting water demand for both the single and multiple dwelling residential sectors with a relative error of about 3%.

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This paper introduces an improved bat algorithm (IBA) with a hybrid mutation strategy to improve its global search ability. In an effort to guide the evolution and reinforce the convergence efficiently, the spatial characteristics of the social and cognitive experience of each bat in the population with the differential evolution (DE) algorithm were developed. More specifically, it has been employed in original bat algorithm (BA) six DE mutation mechanisms, namely the explorative and the exploitative mutation operators. The mutation plays an important role to avoid trapping in a local optimal solution, to ensure the search efficiency of a near global optimal solution, and to increase diversity of population. Also, five unimodal and multimodal benchmark functions were used to test the performance of IBA. The results show that the new bat algorithm performs better than the original bat algorithms for each of the test functions. In addition, IBA could keep the diversity of bats and have a better global search performance. It has been demonstrated that the proposed BA can achieve very low standard deviation for 15 runs of the results. Finally, the proposed method is used to solve two benchmark problems of hydropower operations of multireservoir systems, namely four-reservoir and 10-reservoir systems. The obtained results show that the performance of the proposed method is quite comparable with the results of well-developed traditional linear programming (LP) solvers such as LINGO 8.0, in which for the 15 runs, the best results are as close as 99.9 percent of the global solutions of 308.4 and 1,194.44 for the four-reservoir and 10-reservoir systems, respectively.

... Prof., Dept. of Civ. Engrg., Tufts Univ., Medford, MA 02155) and Charles N. Kroll , SMASCE , (Research Asst., Dept. of Civ. ... Probability plots have been used widely in hydrology as a graphical aid to assess the goodness of fit of alternative distributions. ...

Although much progress has been made in the development ofregional grOlmdwater models and river basin simulation models, previous attempts at linking these two types of models into a workable conjunctive use decision support system for use in comprehensive river basin planning, management, and administration, have not been successful. With recent advances in computer hardware and software technology such as geographic information systems (GIS) and data base management system technology (DBMS), it is now possible to develop a computer based river basin decision support system for improved conjunctive use management ofgroundwater and surface water by linking a finite difference groundwater flow model with a river basin network model.

Accurate and up-to-date peak demand data are essential to ensure that future mains water supply networks reflect current usage patterns and are designed efficiently from an engineering, environmental, and economic perspective. The aim of this paper was to identify the water end-uses that drive peak day demand and to examine their associated hourly diurnal demand patterns based on over 18 months of water consumption data obtained from high-resolution smart meters installed in 230 residential properties across South East Queensland, Australia. Peak day (PD) to average day (AD) ratios between 1 and 1.5 were driven by both external and internal end-uses. However, as the PD:AD ratio increased above 1.5, demand was driven largely by external water usage (i.e., lawn and garden irrigation). Peak hour ratios (i.e., PHPD: PHAD) ranged from 1.3 to 3.0 for the four peak demand days. At the end-use level, the individual end-use category PHPD:PHAD ratios were in the range of 0.7-3.3 for all end-uses, with the exception of external or irrigation. The ratio for this latter end-use category was typically very high, at over 10 times the average irrigation demand. Comparisons with historically based, but currently used, peaking factors used for network distribution modeling suggest that the degree and frequency of high peaking factors are lower now, due to the high penetration of water-efficient technology and growing water conservation awareness by consumers.

Now is an ideal time to reflect, to take stock of where the Australian water industry is at, to scan the trends, disruptions and innovation opportunities that lie ahead, to imagine what the water industry could look like in the next 20 to 30 years, and to work out what it would take to realise that vision. As the weight of history, the push of the present and the pull of the future unfold, there is a need to take control, innovate, advocate and consciously head in the desired direction to ensure that the collective vision of the future water industry is fulfilled. The Water Services Association of Australia (WSAA), the peak industry body that represents over 70 public and privately, owned water or water related organisations, commissioned the Institute to research and write this discussion paper on the trends and potential disruptions to Australia’s urban water futures.

Leaky distribution systems are costly in terms of lost water, potentially adverse water quality effects, and the energy consumed in supplying the leaks. To characterize the energy effectiveness of a leaky segment in a single pipe, several dimensionless parameters are analytically derived, which relate the leak size and location to its associated energy burden and water loss. The computer program EPANET is used to simulate the energy costs of leaks on representative distribution networks. In particular, analysis is performed to illustrate the influence of total system demand, leak location, and topological complexity. Furthermore, the connection between water loss and energy costs illustrates the potential importance of energy costs when pipes are leaky. The impact of leaks on water age is also evaluated through simulation and via a dimensionless expression relating leak size and location to residence time.

Defining and measuring sustainability is a major challenge. This article argues these limitations need not stop us from trying to identify and value the possible impacts of what we are doing, or are thinking about doing, over time periods much longer than the lives of our investments, or even of the lives of those of us living today. Sustainability is a relative concept that must be applied in an environment undergoing multiple changes, changes that are occurring over different temporal and spatial scales. We depend on our water resource systems for our survival and welfare. Yet no one expects them to be restored to, or survive in, their most productive pristine states in the face of increasing development pressures for land in their watersheds and for water in their streams, rivers, lakes, and aquifers. A continuing task of water resource planners and managers is to identify the multiple impacts and tradeoffs resulting from what we who are living today may wish to do for ourselves and our immediate children and what we can only guess our yet-to-be-born descendants may wish us to do, or not do, for them in some distant future. This task must involve professionals from other disciplines in a context much broader than just water management. Once these impacts and tradeoffs are identified, it is then up to the political process to make choices when they are in conflict. All of us need to be a part of this decision-making process.

Os mosteiros e conventos da Idade Média e Moderna, para funcionarem em condições de higiene e salubridade adequadas, careciam de um hidrossistema sólido e tecnicamente eficiente, na forma e no traçado, desde a captação de águas, seu transporte por gravidade, armazenamento e distribuição pela área intramural dos cenóbios, até à descarga dos resíduos domésticos e pluviais. Nesse sentido, o clero regular de outrora ensinou-nos a conquistar e a domesticar a água, ou seja, como se explora, conduz, acumula e administra com racionalidade e inteligência. Os testemunhos abaixo apresentados certificam um repertório de saberes e técnicas acerca do nosso amplo e diversificado património histórico-hidráulico de concepção pragmática e instância religiosa, hoje caídos em desuso e secos ou a funcionar modificados por novos equipamentos mecânicos. Esta afortunada manifestação de experiências e aptidões legadas, referentes à pesquisa e ao uso intensivo da água, legitima uma porção substancial de memória identitária bastante ignorada e ameaçada, que ultrapassa o domínio da tecnologia e urge recuperar e restabelecer na pluralidade da nossa cultura. É uma obrigação ética comum evitar o colapso desses importantes projectos centenários, atribuídos à ousadia e firmeza de espírito dos anónimos monges e frades de antanho. Amiúde, tais infra-estruturas são vitimadas por facilitações mesquinhas e actos abusivos de interesse privado económico-financeiro especulativo, que apagam ou ocultam o seu valor e significado históricos. Por isso, é improrrogável a nossa mobilização cautelar, assente no respeito e na responsabilidade pelos bens herdados das gerações precedentes, a fim de assegurarmos a sua salvaguarda, num propósito correlacionado de usufruto e defesa estáveis do nosso devir civilizacional.

This note proposes models for efficiency and mechanical input power of a group of parallel identical pumps which can be fixed or variable speed. Two approaches are considered. In the first approach, the power characteristic is evaluated from hydraulic and efficiency curves. In the second approach, the mechanical power is approximated directly by a cubic polynomial and scaled by pump speed and number of pumps. In both cases, the obtained power curves are well suited for use in simulation and optimization software; however, if the power data points are available, the second approach can lead to a more accurate representation. The effects of the electric motor efficiency characteristic on the performance of the entire pump plant are also discussed. The developed theory is illustrated by a practical case study. For completeness, the studies are performed using two types of fitted pump hydraulic curves, one quadratic and one described by a power law.

The Water Resources Planning Organization (WARPO) is an exclusive government institution (created by Water Resources Planning Act, 1992) under the ministry of Water Resources Bangladesh for Macro-level water resources planning and management in Bangladesh by pursuing Integrated Water Resources Management (IWRM). It is the central coordinating body for the water sector and acts as an Executive Secretariat of the Executive Committee of the National Water Resources Council (ECNWRC). The Bangladesh Water Act, 2013; The Water Resources Planning Act, 1992; National Water Policy, 1999; Coastal Zone Policy, 2005; National Water Management Plan, 2004; National Water Resources Council (NWRC); the Executive Committee of the National Water Resources Council (ECNWRC), etc. have given mandated task for WARPO. The four main task of WARPO are to prepare and update the National Water Resources Plan (NWRP); update and maintain the National Water Resources Database (NWRD); act as a clearing house role for all projects undertaken by any agency involved in the water sector; and coordinate & implement Integrated Coastal Zone Management (ICZM). From the creation of WARPO, it has made remarkable contribution to water sector, Bangladesh. However, a lot of gaps are existing in this Organization. The existing staffing structure, strength, support and service of WARPO are not sufficient to commensurate with its mandate and redefined functions effectively. This study has identified the contribution of WARPO in Water Sector and at the same time has identified the existing gaps in this organization and finally has recommended the tasks to become the centre of excellence in Water sector Bangladesh.

The use of micro hydroelectric plant in urban pipe networks, based on the combination of a 5 PAT (Pump as Turbine), two regulating valves and two pressure meters, is proposed along with 6 simple automation rules. Its economic benefit is tested on a small pipe network, where the net-7 work geometry, as well as the demand coefficient variation in time and space have been inferred 8 from previously collected data and existing analysis. A similar analysis has been also carried out 9 for different scenarios, where the reduction of pipe installation cost due to a diameter reduction is 10 compared with the increased benefit in energy production. The case study shows that a small in-11 crement of the pipe installation cost, with respect to the minimum required by the nodes minimum 12 pressure, can lead to a larger benefit for energy production.

The quality of water being used by residents in Budiriro is a major health issue. Water system in Budiriro suburb is centralised through the reticulated water system which is not enough for the residents. The serious water shortage in Budiriro has forced residents to rely on unsafe water sources resulting in the area being endemic to waterborne diseases. This study sought to determine the impact of the quality of the water being used by residents in Budiriro. An analytical cross-sectional study was conducted that combined quantitative and qualitative methods. A structured questionnaire was used to obtain information on alternative water sources A total of 72 samples were collected over a period of four months. Twenty-five (25) borehole water samples, 41 well water samples and 8 from the City of Harare tap water. Data from the questionnaires was captured and analyzed using SPSS (statistical package for social science) in line with the objective Sixteen percent (16%) of the boreholes and 56% of wells sampled did not meet the WHO total and faecal coliform standards of zero per 100ml. Thirty-eight percent (38%) of residents use the water without any form of treatment. Results show that residents are potentially exposed to waterborne diseases. This study concludes that water from alternative sources in Budiriro is of poor quality. The study ascertains the relative importance of the use of different sources of water leading to the development of a distribution planning model for different sources of water to Budiriro residents.

A practical monthly optimization model, called SISOPT, is developed for the management and operations of the Brazilian hydropower system. The system, one of the largest in the world, consists of 75 hydropower plants with an installed capacity of 69,375 MW, producing 92% of the nation's electrical power. The system size and nonlinearity pose a real challenge to the modelers. The basic model is formulated in nonlinear programming ͑NLP͒. The NLP model is the most general formulation and provides a foundation for analysis by other methods. The formulated NLP model was first linearized by two different linearization techniques and solved by linear programming ͑LP͒. A comparative analysis was made of the results obtained from the linearized and the NLP models. The results show that the simplest linearized model ͑referred to as the LP model͒ without iteration is suitable for planning purposes. For example, the LP model could be used in system capacity expansion studies or to explore various design parameters in connection with feasibility studies, where details in storage variation are not as important as the power production. With a good initial policy provided by the LP model, the successive linear programming ͑SLP͒ model produced excellent results with fast convergence. The NLP model, the most complex and accurate model in the suite, is particularly suited for setting up guidelines for real-time operations using inflow forecast with frequent updating. The performance of the NLP model was checked against the historical operational records, and the comparison yields indications of superior performance.

Mounding often occurs beneath engineering structures designed to infiltrate reuse water. AQTESOLV software and a spreadsheet solution for Hantush, together with soil moisture water balance (SWAGMAN farm model), were used for quantitatively predicting the height and extent of groundwater mounding underground to assess the groundwater-flow simulations of infiltration from a hypothetical irrigation site. Horizontal and vertical permeability, aquifer thickness, specific yield, and basin geometry are among the aquifer and recharge properties inputs. For 2.2 ha sites, the maximum heights of the simulated groundwater mound ranges up to 0.29 m. The maximum areal extent of groundwater mounding measured from the edge of the infiltration basins of 0.24 m ranges from 0 to 75 m. Additionally, the simulated height and extent of the groundwater mounding associated with a hypothetical irrigation infiltration basin for 2.2 ha development may be applicable to sites of different sizes, using the recharge rate estimated from the SWAGMAN farm model. For example, for a 2.2 ha site with a 0.0002 m/day recharge rate, the irrigation infiltration basin design capacity (and associated groundwater mound) would be the same as for a 1.1 ha site with a 0.0004 m/day recharge rate if the physical characteristics of the aquifer are unchanged. The study claimed that the present modelling approach overcomes the complications of solving the Hantush equation for transient flow. The approach utilised in this study can be applied for other purposes such as measuring the feasibility of infiltrating water, attenuation zone, risk mitigation essential for decision-makers and planning regulators in terms of environmental effects and water use efficiency.

Transient conditions in closed conduits have traditionally been modeled as 1D flows with the implicit assumption that velocity profile and friction losses can be accurately predicted using equivalent 1D velocities. Although more complex fluid models have been suggested, there has been little direct experimental basis for selecting one model over another. This paper briefly reviews the significance of the 1D assumption and the historical approaches proposed for improving the numerical modeling of transient events. To address the critical need for better data, an experimental apparatus is described, and preliminary measurements of velocity profiles during two transient events caused by valve operation are presented. The velocity profiles recorded during these transient events clearly show regions of flow recirculation, flow reversal, and an increased intensity of fluid turbulence. The experimental pressures are compared to a water hammer model using a conventional quasi-steady representation of head loss and one with an improved unsteady loss model, with the unsteady model demonstrating a superior ability to track the decay in pressure peak after the first cycle. However, a number of details of the experimental pressure response are still not accurately reproduced by the unsteady friction model.

Defining and measuring sustainability is a major challenge. This article argues these limitations need not stop us from trying to identify and value the possible impacts of what we are doing, or are thinking about doing, over time periods much longer than the lives of our investments, or even of the lives of those of us living today. Sustainability is a relative concept that must be applied in an environment undergoing multiple changes, changes that are occurring over different temporal and spatial scales. We depend on our water resource systems for our survival and welfare. Yet no one expects them to be restored to, or survive in, their most productive pristine states in the face of increasing development pressures for land in their watersheds and for water in their streams, rivers, lakes, and aquifers. A continuing task of water resource planners and managers is to identify the multiple impacts and tradeoffs resulting from what we who are living today may wish to do for ourselves and our immediate children and what we can only guess our yet-to-be-born descendants may wish us to do, or not do, for them in some distant future. This task must involve professionals from other disciplines in a context much broader than just water management. Once these impacts and tradeoffs are identified, it is then up to the political process to make choices when they are in conflict. All of us need to be a part of this decision-making process.

Six storm-water best management practices ͑BMPs͒ for treating urban rainwater runoff were evaluated for cost and effectiveness in removing suspended sediments and total phosphorus. Construction and annual operating and maintenance ͑O and M͒ cost data were collected and analyzed for dry extended detention basins, wet basins, sand filters, constructed wetlands, bioretention filters, and infiltration trenches using literature that reported on existing storm-water BMP sites across the United States. After statistical analysis on historical values of inflation and bond yields, the annual O and M costs were converted to a present worth based on a 20-year life and added to the construction cost. The total present cost of each storm-water BMP with the 67% confidence interval was reported as a function of the water quality design volume, again with a 67% confidence interval. Finally, the mass of total suspended solids and total phosphorus removed over the 20-year life was estimated as a function of the water quality volume. For the six storm-water BMPs investigated, results show that, ignoring land costs, constructed wetlands have been the least expensive to construct and maintain if appropriate land is available. However, since wetlands typically require more land area to be effective, land acquisition costs may result in wetlands being significantly more expensive than other storm-water BMPs that require less area. The results can be used by planners and designers to estimate both the total cost of installing a storm-water BMP and the corresponding total suspended solids and total phosphorus removal.

Attributes of an effective infrastructure adaptation planning process as well as methods for choosing among adaptation strategies are described. The major attributes include: (1) a vulnerability assessment, (2) proactive adaptation strategies that are implemented over time and space, (3) climate change scenario analysis including climate surprises to handle the uncertainty of the future climate, (4) actions that are robust and/or flexible and adjustable, (5) a planned, progressive approach that ties implementation to critical thresholds of actual climate changes and preserves options for future actions, (6) evaluation with multiple social, economic and environmental criteria, and integration of local stakeholders into the planning process. Multiple methods can be used to generate and evaluate adaptation strategies. A subset of the key attributes is then used in a case study of urban drainage management, which was designed and implemented to illustrate these attributes. It is shown that multicriteria scenario analysis can be effectively used to generate and evaluate alternative adaptation strategies. The identification of when critical thresholds are reached under conditions of climate variability and change is a major research need.

Defining and measuring sustainability is a major challenge. This article argues these limitations need not stop us from trying to identify and value the possible impacts of what we are doing, or are thinking about doing, over time periods much longer than the lives of our investments, or even of the lives of those of us living today. Sustainability is a relative concept that must be applied in an environment undergoing multiple changes, changes that are occurring over different temporal and spatial scales. We depend on our water resource systems for our survival and welfare. Yet no one expects them to be restored to, or survive in, their most productive pristine states in the face of increasing development pressures for land in their watersheds and for water in their streams, rivers, lakes, and aquifers. A continuing task of water resource planners and managers is to identify the multiple impacts and tradeoffs resulting from what we who are living today may wish to do for ourselves and our immediate children and what we can only guess our yet-to-be-born descendants may wish us to do, or not do, for them in some distant future. This task must involve professionals from other disciplines in a context much broader than just water management. Once these impacts and tradeoffs are identified, it is then up to the political process to make choices when they are in conflict. All of us need to be a part of this decision-making process.

This paper proposes a new methodology for the optimal design of water network sectorization, which is 6 an essential technique for improving the management and security of multiple-source water supply 7 systems. In particular, the network sectorization problem under consideration concerns the definition of 8 isolated district meter areas, each of which is supplied by its own source (or sources) and is completely 9 disconnected from the rest of the water system through boundary valves or permanent pipe sectioning. 10

Water Distribution System (WDS) models when applied with real-time data may lead to 7 improve system control, and in doing so, meet consumer and regulatory demands. Such real-time 8 modelling often overlooks the multiple sources of system uncertainty that cascade into model 9

Fluid transients result in a substantial amount of data as pressure waves propagate throughout pipes. A new generation of leak detection and pipe roughness calibration techniques has arisen to exploit those data. Using the interactions of transient waves with leaks, the detection, location, and quantification of leakage using a combination of transient analysis and inverse mathematics is possible using inverse transient analysis ͑ITA͒. This paper presents further development of ITA and experimental observations for leak detection in a laboratory pipeline. The effects of data and model error on ITA results have been explored including strategies to minimize their effects using model error compensation techniques and ITA implementation approaches. The shape of the transient is important for successful application of ITA. A rapid input transient ͑which may be of small magnitude͒ contains maximum system response information, thus improving the uniqueness and quality of the ITA solution. The effect of using head measurements as boundary conditions for ITA has been shown to significantly reduce sensitivity, making both detection and quantification problematic. Model parsimony is used to limit the number of unknown leak candidates in ITA, thus reducing the minimization problem complexity. Experimental observations in a laboratory pipeline confirm the analysis and illustrate successful detection and quantification of both single and multiple leaks.

This paper shows how pipe replacements and control valve installations can be optimized in water distribution networks to reduce leakage, under minimum nodal pressure constraints. To this end, a hybrid multiobjective algorithm, which has pipe diameters and valve positions and settings as decisional variables, was set up. The algorithm also enables identification of the isolation valves that have to be closed in order to improve effectiveness of the control valves installed. The algorithm is initially applied to the optimal valve location problem, where it explores the trade-off between the number of installed control valves and the daily leakage volume. In this context, the analysis of the results proves the new algorithm more effective than a multiobjective genetic algorithm widely adopted in the scientific literature. Furthermore, it shows that if some isolation valves identified ad hoc are closed in the network, the installation of control valves determines larger leakage volume reductions. In a second application of the algorithm, pipe replacements and control valve installations are simultaneously performed. In this case, a Pareto front of trade-off solutions between installation costs and daily leakage volume is obtained. For the choice of the final solution within the front, an economic criterion based on the long-term convenience analysis is also illustrated.

The design of District Metered Areas (DMAs) in existing water distribution networks, 6 especially in urban areas, involves a high number of decision variables and the effects of 7 implementing them in districts have to be evaluated, in order not to affect the quality of the 8 service to customers.

An epidemiologic study of childhood leukemia and central nervous system cancers that occurred in the period 1979 through 1996 in Dover Township, N.J., is being conducted. Because groundwater contamination has been documented historically in public-and private-supply wells, there is the possibility of exposure through this pathway. The Dover Township area has been primarily served by a public water supply that relies solely on groundwater; therefore, a protocol has been developed for using a water-distribution model such as EPANET as a tool to assist the exposure assessment component of epidemiologic investigation. The model is being used to investigate the question of human exposure to groundwater contaminants. Because of the unavailability of historical data, the model was calibrated to the present-day (1998) water-distribution system characteristics. Pressure data were gathered simultaneously at 25 hydrants throughout the distribution system using continuous recording pressure data loggers during 48 h tests in March and August 1998. Data for storage tank water levels, system demand, and pump and well status (on/off) were also obtained. Field data gathering procedures, calibration results, and water-quality simulation using a naturally occurring element (barium), as well as an analysis indicating the percent of water originating from points of entry to the water-distribution system for 1998 conditions, are presented.

During the last decade, evolutionary methods such as genetic algorithms have been used extensively for the optimal design and operation of water distribution systems. More recently, ant colony optimization algorithms (ACOAs), which are evolutionary methods based on the foraging behavior of ants, have been successfully applied to a number of benchmark combinatorial optimization problems. In this paper, a formulation is developed which enables ACOAs to be used for the optimal design of water distribution systems. This formulation is applied to two benchmark water distribution system optimization problems and the results are compared with those obtained using genetic algorithms. The findings of this study indicate that ACOAs are an attractive alternative to GAs for the optimal design of water distribution systems, as they outperformed GAs for the two case studies considered both in terms of computational efficiency and their ability to find near global optimal solutions.

This paper employs an economic-engineering optimization model to explore water supply options for environmental restoration of the Colorado River Delta, Mexico. Potential water sources include reductions in local agricultural and urban water use through water markets, wastewater reuse, and additional Colorado River flows from the United States. For these alternatives, the optimization model estimates operating and water scarcity costs, water scarcity volumes, and marginal economic costs of environmental flows and values of additional Colorado River flows from the United States over a range of required delta environmental flows. Economic values for agricultural and urban water uses were estimated by two ancillary models. The results provide insights into economically promising water supplies for restoration activities. Quantifying the trade-off between agricultural and urban economic valuation and environmental flows provides a framework for decision makers to quantify their valuation of environmental flows. The model also provides a framework for integrating additional knowledge of the system as information becomes available.

Decision making in environmental projects can be complex and seemingly intractable, principally because of the inherent trade-offs between sociopolitical, environmental, ecological, and economic factors. The selection of appropriate remedial and abatement strategies for contaminated sites, land use planning, and regulatory processes often involves multiple additional criteria such as the distribution of costs and benefits, environmental impacts for different populations, safety, ecological risk, or human values. Some of these criteria cannot be easily condensed into a monetary value, partly because environmental concerns often involve ethical and moral principles that may not be related to any economic use or value. Furthermore, even if it were possible to aggregate multiple criteria rankings into a common unit, this approach would not always be desirable because the ability to track conflicting stakeholder preferences may be lost in the process. Consequently, selecting from among many different alternatives often involves making trade-offs that fail to satisfy 1 or more stakeholder groups. Nevertheless, considerable research in the area of multicriteria decision analysis (MCDA) has made available practical methods for applying scientific decision theoretical approaches to complex multicriteria problems. This paper presents a review of the available literature and provides recommendations for applying MCDA techniques in environmental projects. A generalized framework for decision analysis is proposed to highlight the fundamental ingredients for more structured and tractable environmental decision making.

Analogous to the field of geomorphology (a subfield of geology that deals with the structure and evolution of the surface of the earth), the new field of hydromorphology (a subfield of hydrology), deals with the structure, evolution, and dynamic morphology of hydrologic systems over time (e.g., years, decades, and centuries). The need for this new subfield of hydrology stems from the enormous societal challenges and demands resulting from a growing human population combined with the pervasive human impacts on environmental and water resource systems. In many regions, the hydrologic cycle has been transformed by human activities that impact water use, land use, and climate at nearly all spatial and temporal scales. Human influences tend to interact and manifest themselves in complex ways, so that it is now difficult to find a watershed subject only to natural or unimpacted hydrologic conditions. Nearly every hydrologic method upon which our profession is based will need to be adapted to account for the increased uncertainty and nonstationarity, which have become the central challenge of our profession. The science of hydromorphology involves the development of a conceptual basis for improving our understanding of the impact of humans on the hydrosphere. Hydromorphologic engineering involves the development of methods to detect, attribute, design, manage, and predict water resources in a hydrosphere, which is subject to multiple and interacting sources of uncertainty and nonstationarity.

Forum papers are thought-provoking opinion pieces or essays founded in fact, sometimes containing speculation, on a civil engineering topic of general interest and relevance to the readership of the journal. The views expressed in this Forum article do not necessarily reflect the views of ASCE or the Editorial Board of the journal.