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[Display omitted] • A model for multi-objective optimization operation of multiple water sources under uncertainties was proposed. • Uncertainties in inflow and water demand forecasts can be considered simultaneously, and the correlation between uncertainties can be considered quantitatively. • The impact of inflow-water demand forecast uncertainties and their correlations on water resource operations are explored for water resources managers. Uncertainties in inflow and water demand forecasts bring risks to water resources management. Therefore, the research on multi-objective optimization operation of multiple water sources under uncertainties holds critical research significance and application value. This paper proposes a model for the multi-objective optimization operation of multiple water sources that can consider the inflow and water demand forecast dual uncertainties. In handling uncertainties, this paper adopts a scenario generation method based on joint distribution-Monte Carlo (JDMC), which allows for a quantitative consideration of the correlation between uncertainties. Moreover, the variable weight method and LINGO 20.0 are employed for solving multi-objective optimization issues to obtain stable Pareto frontiers. The proposed model is applied to the water receiving area inside Jiangsu Province of the South-to-North Water Transfer East Route Project (SNWTERP) in China. The main findings are as follows: 1) The impact of the inflow and water demand forecast uncertainties on the operation results is synergistic rather than antagonistic. Considering only a single uncertainty may result in water receiving area facing more severe water shortages or purchasing spot water at high prices. 2) There is a strong spatial correlation between uncertainties. If we ignore or only qualitatively consider the correlation between uncertainties, the impact of uncertainties on operation results will be underestimated or overestimated. 3) The Pareto frontiers are convex functions, indicating that decision-makers should choose a solution in the middle part. [ABSTRACT FROM AUTHOR]

[Display omitted] • Hydrological model predictions are crucial for risk-based water management decisions. • Errors in hydrological predictions are typically neglected for risk-based decision-making. • New framework shows neglecting errors over-estimates yield, under-estimates risks. • Outcomes underscore the need to account for hydrological errors in decision-making. Risk-based decision making for water resource systems often relies on streamflow predictions from hydrological models. These predictions are integral for estimating the frequency of high consequence extreme events, such as floods and droughts. However, streamflow predictions are known to have errors due to various factors such as incomplete hydrological understanding, parameter misspecification, and uncertain data. Despite these errors being well known, they are frequently neglected when undertaking risk-based decision-making. This paper demonstrates that neglecting hydrological errors can impact on drought risk estimation for high stakes decisions with potentially severe consequences for water resource system performance. A generic framework is introduced to evaluate the impact of hydrological errors for a wide range of water resource system properties. This framework is applied in two Australian case study catchments, where we use a stochastic rainfall model, the GR4J hydrological model, a residual error model, and a simplified reservoir storage model to estimate water resource performance metrics (risk and yield). The results underscore the impact of neglecting hydrological errors on decision-making. In one case study catchment, the yield was over-estimated by ∼15%–55%, resulting in the (actual) risk of running out of water being ∼2–30 times larger than reservoir design. The magnitude of these errors in water resource performance metrics is striking, especially considering that the streamflow predictions appear reasonable based on typical performance metrics (e.g., NSE of ∼0.7). The errors in performance metrics stem from the complex propagation of hydrological errors through the water resource system modelling chain. By accounting for critically important hydrological errors we can mitigate highly erroneous risk estimates and improve decision-making related to water resource management. [ABSTRACT FROM AUTHOR]

• Numerous science and policy debates occur over efficient aquifer protection measures. • This paper formulates a basin scale hydroeconomic optimization framework. • Its application is to North America's Middle Rio Grande Basin. • It discovers least cost aquifer protection measures for handling climate water stress. • Results are presented showing the marginal and total cost of aquifer protection. Where surface and groundwater are managed conjunctively, the stress on water supplies from climate change can significantly influence water use patterns as well as the economic value and sustainability of those uses. However, aquifer protection can be an expensive proposition because water uses that currently rely on aquifer pumping may produce considerable economic value that would be lost if protection measures are carried out. Evidence from climate-stressed regions has attracted research addressing the costs and benefits of aquifer protection plans. Despite these efforts, few peer-reviewed papers have examined water use patterns that minimize the economic costs of aquifer protection. This work presents an original approach to address that gap by developing and applying a basin scale hydroeconomic optimization model of North America's Middle Rio Grande Basin to explore impacts of new policies not yet implemented supporting aquifer protection. It also gives model access to readers or stakeholders to experiment with their own scenarios to assess impacts of alternative aquifer protection plans. The model accounts for surface and groundwater storage, irrigation, urban, environmental, and recreational demands, surface water inflows under various climate scenarios, groundwater pumping and recharge, substitute water prices, crop water use, evaporation, as well as institutional constraints governing water use. The objective is implemented by finding the optimized discounted net present value of economic benefits summed over uses, sectors, and regions from use of surface water and connected aquifers. Results are shown for each of six water supply scenarios, two substitute water prices, and two system operation rules. To address impacts of aquifer protection targets, groundwater sustainability targets are specified and enforced as constraints for each of the region's two major aquifers. We assess total and marginal cost of achieving two targeted aquifer protection levels by identifying optimized surface use and groundwater pumping for each of 24 scenarios. Results show that climate change, in the form of reduced and highly variable inflows, considerably drives up the cost of protecting aquifer sustainability, amplified by the conjunctive nature of the system. Future work points to a need to assess economic performance of various water conservation measures as well as reducing costs of substitute water through measures such as technical advance in desalination, recycling and reuse, substitution of other resources for water, better characterization of existing aquifers, and development of new groundwater supplies. [ABSTRACT FROM AUTHOR]

Water resources in Mediterranean regions are under increasing pressure due to climate change, economic development, and population growth. Many Mediterranean rivers have their headwaters in mountainous regions where hydrological processes are driven by snowpack dynamics and the specific variability of the Mediterranean climate. A good knowledge of the snow processes in the Mediterranean mountains is therefore a key element of water management strategies in such regions. The objective of this paper is to review the literature on snow hydrology in Mediterranean mountains to identify the existing knowledge, key research questions, and promising technologies. We collected 620 peer-reviewed papers, published between 1913 and 2016, that deal with the Mediterranean-like mountain regions in the western United States, the central Chilean Andes, and the Mediterranean basin. A large amount of studies in the western United States form a strong scientific basis for other Mediterranean mountain regions. We found that: (1) the persistence of snow cover is highly variable in space and time but mainly controlled by elevation and precipitation; (2) the snowmelt is driven by radiative fluxes, but the contribution of heat fluxes is stronger at the end of the snow season and during heat waves and rain-on-snow events; (3) the snow densification rates are higher in these regions when compared to other climate regions; and (4) the snow sublimation is an important component of snow ablation, especially in high-elevation regions. Among the pressing issues is the lack of continuous ground observation in high-elevation regions. However, a few years of snow depth (HS) and snow water equivalent (SWE) data can provide realistic information on snowpack variability. A better spatial characterization of snow cover can be achieved by combining ground observations with remotely sensed snow data. SWE reconstruction using satellite snow cover area and a melt model provides reasonable information that is suitable for hydrological applications. Further advances in our understanding of the snow processes in Mediterranean snow-dominated basins will be achieved by finer and more accurate representation of the climate forcing. While the theory on the snowpack energy and mass balance is now well established, the connections between the snow cover and the water resources involve complex interactions with the sub-surface processes, which demand future investigation. [ABSTRACT FROM AUTHOR]

• Proposes an MCDM framework for robust water resources management under uncertainty. • Develops an aggregation method for conflict resolution and uncertainty estimation. • Proposes a novel SMAA-GRA model to consider uncertainties in MCDM problems. • Conducts significance analysis to test effects of uncertainty on decision-making. • Enables a risk-informed water resource decision to be made with higher reliability. Water planner and managers always work in a changing and uncertain environment, since the majority of water resource-related data is imprecise or uncertain to some extent. MCDM (multi-criteria decision making) is a well-suited decision support tool for water resources management, however multiple uncertainties existed in criteria weights (CWs) and performance values (PVs) hinder the application of MCDM methods in real-world problems. This paper proposes an application-oriented stochastic MCDM framework for robust water resources management under uncertainty. A weight aggregation approach based on the game theory coupled with feasible weight space (FWS) is developed for conflict resolution and uncertainty estimation. We propose a novel SMAA-GRA model by combining the stochastic multi-criteria acceptability analysis (SMAA) theory and grey relational analysis (GRA). The risk of errors in decision making and rank uncertainty degree are utilized to assess decision-making uncertainty. We perform significance analysis to examine the impacts of input parameter uncertainties on the final assessment of alternatives. The proposed framework is demonstrated via two water resources management case studies. Numerical experiments are conducted to investigate the robustness and computational efficiency of the framework as well as the effects of uncertainty level and probability distribution type on decision-making results. The results indicate that the framework enables water managers to examine the robustness of final decisions and allows a risk-informed water resource decision to be made with higher reliabilities. [ABSTRACT FROM AUTHOR]

• The adaptive irrigation behaviors might worsen the water scarcity in the CRB. • Clustering identified bold, prudent, and forward-looking farmer classes. • We indicated specific parameters for uncertainty reduction in human systems. The Colorado River Basin (CRB) supports the water supply for seven states and forty million people in the Western United States (US) and has been suffering an extensive drought for more than two decades. As climate change continues to reshape water resources distribution in the CRB, its impact can differ in intensity and location, resulting in variations in human adaptation behaviors. The feedback from human systems in response to the environmental changes and the associated uncertainty is critical to water resources management, especially for water-stressed basins. This paper investigates how human adaptation affects water scarcity uncertainty in the CRB and highlights the uncertainties in human behavior modeling. Our focus is on agricultural water consumption, as approximately 80% of the water consumption in the CRB is used in agriculture. We adopted a coupled agent-based and water resources modeling approach for exploring human-water system dynamics, in which an agent is a human behavior model that simulates a farmer's water consumption decisions. We examined uncertainties at the system, agent, and parameter levels through uncertainty, clustering, and sensitivity analyses. The uncertainty analysis results suggest that the CRB water system may experience 13 to 30 years of water shortage during the 2019–2060 simulation period, depending on the paths of farmers' adaptation. The clustering analysis identified three decision-making classes: bold, prudent, and forward-looking, and quantified the probabilities of an agent belonging to each class. The sensitivity analysis results indicated agents whose decision-making models require further investigation and the parameters with the higher uncertainty reduction potentials. By conducting numerical experiments with the coupled model, this paper presents quantitative and qualitative information about farmers' adaptation, water scarcity uncertainties, and future research directions for improving human behavior modeling. [ABSTRACT FROM AUTHOR]

Highlights • Artificial Neural Network approaches were used to predict water trading prices (WTP). • Prices forecast showed greater agreement with actual water prices. • Water allocations, cereal and meat prices were significant determinants of WTP. Abstract This paper proposes an integrated (hybrid) Artificial Neural Network-Bayesian (ANN-B) modelling approach to improve the accuracy of predicting seasonal water allocation prices in Australia's Murry Irrigation Area, which is part of one of the world's largest interconnected water markets. Three models (basic, intermediate and full), accommodating different levels of data availability, were considered. Data were analyzed using both ANN and hybrid ANN-B approaches. Using the ANN-B modelling approach, which can simulate complex and non-linear processes, water allocation prices were predicted with a high degree of accuracy (R BASIC = 0.93, R INTER. = 0.96 and R FULL = 0.99); this was a higher level of accuracy than realized using ANN. This approach can potentially be integrated with online data systems to predict water allocation prices, enable better water allocation trade decisions, and improve the productivity and profitability of irrigated agriculture. [ABSTRACT FROM AUTHOR]

Summary Water represents an essential element for the life of all who inhabit our planet. But the random nature of this resource, which is manifested by the alternation of wet periods and dry periods, makes it even more precious. Whatever the approach (water planning, water management, drought, economy), in order to maximise the profit produced by the allocation of water it is necessary an understanding of the relationships between physical variables as precipitation, temperatures, streamflows, reservoir volumes, piezometric levels, water demands and infrastructures management. This paper attends to provide a review of fundamental water scarcity and drought indexes that enables to assess the status of a water exploitation system. With the aim of a better water management and governance under water scarcity conditions., this paper also presents a classification of indexes to help decision makers and stakeholders to select the most appropriate indexes, taking as the starting point the objectives of the analysis and the river basin features. [ABSTRACT FROM AUTHOR]

Summary Water markets have increasingly been adopted as a reallocation tool around the world as water scarcity intensifies. Water markets were first introduced in Australia in the 1980s, and water entitlement and allocation trade have been increasingly adopted by both private individuals and governments. As well as providing an overview of water policy in Australia since the 1900s, this paper examines the adoption of water trading in the southern Murray–Darling Basin of Australia (the largest hydrologically connected water market in Australia), and investigates the associated social, economic and environmental impacts that have arisen from the implementation of water markets. This study found that up to 86% of irrigators in one state in the southern Murray–Darling Basin had undertaken at least one water market trade by 2010–2011, hence, water market strategies are now a common tool employed by irrigators to assist their farm management. A variety of institutional, policy and informational changes are identified to increase the benefits from water markets in the future. There is no doubt that managing the impact of climate change and water scarcity are intertwined, suggesting that policy, institutional and governance responses should be similarly structured and coordinated. [ABSTRACT FROM AUTHOR]

Well-designed public policy stimulates social progress. However, when governments translate political vision into programmes for social change, the complexity of issues can overwhelm the policy-making process, creating disappointment and suboptimal outcomes. In this paper we examine why evidence-based policy-making approaches often fail to provide policy-makers with credible, consistent and clear outcomes matching broad social interest. The need for public policy primarily arises from a lack of perfect knowledge, which causes individuals and agencies to behave in ways that counter social interest. We therefore suggest that effective public policy formulation involves: determining what evidence is available, relevant and useful; as well as identifying critical gaps to making public policy necessary and meaningful. Murray-Darling Basin case examples highlight key stages in effective natural resource policy formulation, and sources of difficulties that need to be managed to maximize scientific contributions. These examples show that effective public policy decisions can still be made and information asymmetry managed via strong evidence, expert analysis to verify that evidence, and an understanding of knowledge gaps such that critical interventions can be agreed upon and objectives achieved in view of how they will be managed and resourced. Finally, we draw attention to the opportunities available and challenges that exist for hydrologists, economists and other social scientists to work together in assisting the policy process, and in particular to minimize the burden of information constraints in making effective water resource policy. [ABSTRACT FROM AUTHOR]

• A new form IBWT is proposed to cope with efficiency declines of typical IBWT. • Joint operation coordinating water supply, transfer and receipt rules are derived. • A three-step framework is developed to identify these DIBWT operations. • DIBWT can balance transfer-supply-demand while preserving ecological flow. As the efficiency of the long-running inter basin water transfer (IBWT) projects declines, the increasing water crisis in the intake area and the deteriorating ecosystem problems in the transferred area have gradually worsened. In this paper, a new form of IBWT, the dual-IBWT (DIBWT), is defined, in which the original transferred area (OTA) and additional transferred area (ATA) are integrated to transfer water resource from two basins to a corporate intake area (CIA). Unlike a typical IBWT, the OTA is one of the transferred areas for the CIA as well as the recipient area of the ATA and plays a dual role in this DIBWT system. A multi-objective DIBWT model involving interconnected OTA and ATA submodels is developed for fulfilling joint transfer targets, flattening water transfer fluctuations, and replenishing ecological flow demands. Then, a three-step framework is presented to derive the multi-resource joint operation rules coordinating the water-supply, water-transfer and water-receipt rules together. In particular, the simulation-optimization approach (SO) is applied to obtain the optimal solution based on a time series of 56 years. The Jialing across Han River to Wei River Water Transfer (JHW-DIBWT) project in western China is used as a case study to assess the performance of the DIBWT compared to a typical IBWT. The results indicate that the JHW-DIBWT has significant advantages in alleviating the conflicts of transfer-supply-demand and restoring the river ecosystem with the aid of additional water resources. Meanwhile, its superiority is revealed by the corresponding joint operation rules of the water-supply, the water-transfer and the water-receipt rule curves, which also can serve as a practical guide for multi-objective and multi-resource water system management. Therefore, the main focus of this paper is not limited to compare the performance between these two IBWTs, but more importantly, it provides a promising framework for extending the study of different form of IBWTs. [ABSTRACT FROM AUTHOR]

• Propose an indirect way of cooperation in transboundary river management. • Appropriate data sharing and selection in water system operation is vital. • Sharing data on available water storages foster hydropower production. Water resources management in the Lancang-Mekong River Basin (LMRB) is challenging in face of the complex trans-national geopolitical context, the acceleration of hydropower dam expansion, and the growing demands for energy, food, and riverine ecosystem preservation across the basin. Centralised management through coordinated operation of all the basin water infrastructures ("hard cooperation") across the river basin is ideal but hard to achieve given the existing geopolitical context of the region. To overcome these barriers and facilitate a more adaptive and reliable operation of the LMRB's water system, this paper focuses on the concept of "soft-cooperation", i.e. the idea of indirectly fostering cooperation by sharing data across countries to inform the non-cooperative (or independent) operation of their systems. Here, we first quantify existing riparian conflicts and synergies for the non-cooperative scenario, where upstream and downstream act independently without any form of cooperation, and for the "hard cooperation" configuration, where an ideal centralised operator jointly operates all the infrastructures. Then a "soft cooperation" scheme assuming data sharing across riparian countries is evaluated. The most effective and informative data is selected via machine learning and used to inform the design of the river reservoir system operation via evolutionary multiobjective direct policy search. Results show that the riparian conflicts around water mainly exist between the sectors, i.e. hydropower production vs ecosystem conservation, rather than among countries. For reservoirs with various capacities and locations, the value of information varies. Generally, sharing data about the water currently available in the different river storages results in a large improvement in hydropower production. This study highlights the value of appropriate data sharing and selection in water system operation as an indirect way of promoting cooperation in transboundary river management. [ABSTRACT FROM AUTHOR]

• We developed a novel analytical model for regional groundwater transit time distributions s accounting for the impact of stormwater infiltration systems. • Global sensitivity analysis successfully identifies the most important parameters for urban groundwater TTDs. • The urban groundwater flow regime cannot be fully restored to the pre-urban conditions even with the aid of stormwater infiltration systems. The stormwater infiltration system (SIS) has been recognized as a feasible way to manage stormwater and restore streamflow. As a lumped representation of the flow and transport processes, the groundwater transit time distribution (TTD) is highly relevant to this restoration goal. However, the influence of the SIS on groundwater TTDs has rarely been studied. In this paper, we propose a novel analytical model for groundwater TTDs in regional urban aquifers accounting for the impact of the SIS. This analytical solution is developed for a homogeneous 2-D cross-section of an idealized unconfined aquifer following the Dupuit-Forchheimer assumption. The analytical solution is verified through the comparison with simulated TTDs using the Lagrangian particle tracking algorithm. The global sensitivity analysis reveals that the stormwater infiltration rate, the number of infiltration facilities, the size of the urban area, and the evapotranspiration are the most important factors for groundwater mean transit times (MTTs). Although groundwater discharge and MTT can be restored to the pre-urban one, groundwater TTDs will inevitably deviate from the pre-urban ones due to the alteration from diffuse recharge to infiltration-focused recharge, indicating that the urban groundwater flow regime cannot be fully restored to the pre-urban conditions. Overall, as a first-order approximation of the real-world urban groundwater system, the proposed analytical model provides decision-making support for urban water resources management and the design of the SIS. [ABSTRACT FROM AUTHOR]

Summary: The hydrological cycle has been substantially influenced by climate change and human activities. It is therefore of utmost importance to analyze the impact of climate change on hydrology, particularly on a regional scale, in order to understand potential future changes of water resources and water-related disaster, and provide support for regional water management. However, during the evaluation of climate change impact on hydrology or water resources, large uncertainty exists. In this paper, the Soil Water Assessment Tool (SWAT) model is used to investigate the potential impact of climate change on hydrology of the upper reaches of Qiantang River Basin, East China, for the future period 2011–2100. The uncertainty is considered by employing upgraded reliability ensemble averaged GCM climate projections under three emission scenarios A1B, A2 and B1 for three different stages of the future period. These projections are downscaled and used in the hydrological model. Impact of climate change on precipitation, potential evapotranspiraton and river runoff is then investigated. The model calibration and validation outcomes show reasonable performance of the SWAT model. The final results suggest that annual river runoff will likely decrease almost under all emission scenarios and time stages of the future period. Particularly, at Jinhua Station, substantial decrease of annual river runoff can be noticed, indicating less water resource possibly available for the region in future. Simulated monthly patterns show that the largest decrease will likely occur in winter while increases will occur in summer, implying possible more water-related disasters in this region. However, it is also noticed that the change signs/amount could be different under different emission scenarios and time stages, indicating large uncertainty involved in the impact analysis. [ABSTRACT FROM AUTHOR]

Summary: The climate scenarios of the IPCC suggest that adaptation to future climate change will be required. The North Sea Region, a marginal sea of the Atlantic Ocean between Great Britain, Scandinavia, Germany, the Netherlands and Belgium, is particularly affected due to rising sea level and a changing water balance. Water management plays a key role in sustainable management of natural and societal resources. This paper presents a participatory study of community approaches to regional adaptation to climate change. Water management adaptation options to regional climate induced changes until 2050 were developed together with stakeholders for the Wesermarsch County (Northern Germany). Available information on expected regional climate change and a modelling study on hydrological change suggested that adaptation of water management will be required until 2050. A regional stakeholder forum formulated a vision on how the Wesermarsch should look like in 2050. Following the holistic approach of collaborative planning, two stakeholder groups developed an adaptation portfolio on how urban and rural areas could adapt their water management to cope with the expected changes. Since most of the stakeholders do not want the county to undergo significant changes in terms of landscape and land use, they proposed technical measures to enforce flood protection and enhance the performance of the existing water management system. Adaptation in terms of land use change was not proposed although information on comparable examples from similar regions was available. To justify the proposed adaptation options, available information on expected climate change impacts was used selectively. Uncertainty in model projections was partly ignored to legitimate suggesting inflexible (technical) adaptation measures. However, collaborative planning proved to be helpful for a joint adaptation to climate change at the regional scale. Stakeholders as well as scientists took active part in the participatory learning process as required by EU directives. [Copyright &y& Elsevier]

Summary: Planning of regional and urban water resources, and in particular with Integrated Urban Water Management approaches, often considers inter-relationships between human uses of water, the health of the natural environment as well as the cost of various management strategies. Decision makers hence typically need to consider a combination of social, environmental and economic goals. The types of strategies employed can include water efficiency measures, water sensitive urban design, stormwater management, or catchment management. Therefore, decision makers need to choose between different scenarios and to evaluate them against a number of criteria. This type of problem has a discipline devoted to it, i.e. Multi-Criteria Decision Analysis, which has often been applied in water management contexts. This paper describes the application of Subjective Logic in a basic Bayesian Network to a Multi-Criteria Decision Analysis problem. By doing this, it outlines a novel methodology that explicitly incorporates uncertainty and information reliability. The application of the methodology to a known case study context allows for exploration. By making uncertainty and reliability of assessments explicit, it allows for assessing risks of various options, and this may help in alleviating cognitive biases and move towards a well formulated risk management policy. [ABSTRACT FROM AUTHOR]

Summary: Public water supply systems are designed to maintain water supply through extended periods of dry weather without excessive cost or environmental damage. During a drought, water suppliers can take further measures to enhance supplies or reduce demand. The introduction of drought measures is usually formalised in a drought plan, but there is often little evidence that the plan will prove successful during a range of feasible droughts. As the climate changes, recent hydrological data may be a poor guide to future drought, and planned actions may prove insufficient to maintain adequate water supplies. This paper describes a method for testing the resilience of water company drought plans to droughts that are outside recent hydrological experience. Long severe droughts of the nineteenth century provide an opportunity to test water supply system behaviour in a range of realistic droughts. The method developed combines system modelling with an interactive approach that asks water system managers to work through the actions that they would take at different stages of the drought, without knowledge of subsequent drought development. The approach was tested for two contrasting English water resource systems. In both cases, the existing water supply and drought planning measures succeeded in maintaining water supply, but significant demand restrictions and engineering measures had to be introduced. Wider use of the method by water supply planners should allow the refinement of drought and water supply plans, and will also create increased awareness of the actions necessary to manage a range of droughts. [ABSTRACT FROM AUTHOR]

Summary: Modern water resources management has adopted natural flow regimes as reasonable targets for river restoration and conservation. The characterization of a natural flow regime begins with the development of hydrologic statistics from flow records. However, little guidance exists for defining the period of record needed for regime determination. In Taiwan, the Taiwan Eco-hydrological Indicator System (TEIS), a group of hydrologic statistics selected for fisheries relevance, is being used to evaluate ecological flows. The TEIS consists of a group of hydrologic statistics selected to characterize the relationships between flow and the life history of indigenous species. Using the TEIS and biosurvey data for Taiwan, this paper identifies the length of hydrologic record sufficient for natural flow regime characterization. To define the ecological hydrology of fish communities, this study connected hydrologic statistics to fish communities by using methods to define antecedent conditions that influence existing community composition. A moving average method was applied to TEIS statistics to reflect the effects of antecedent flow condition and a point-biserial correlation method was used to relate fisheries collections with TEIS statistics. The resulting fish species–TEIS (FISH–TEIS) hydrologic statistics matrix takes full advantage of historical flows and fisheries data. The analysis indicates that, in the watersheds analyzed, averaging TEIS statistics for the present year and 3 years prior to the sampling date, termed MA(4), is sufficient to develop a natural flow regime. This result suggests that flow regimes based on hydrologic statistics for the period of record can be replaced by regimes developed for sampled fish communities. [Copyright &y& Elsevier]

Summary: Water issues are inherently local and inter-dependent and almost fully reliant on the interaction between humans and their socio-technical environments. Hence, the development of water management policies requires evidence-based information that deals with complex, contextual and multi-faceted issues. Composite indicator methodologies have been found to be useful tools supporting policy development and decision making in several fields. Targeted water management decisions can benefit from indicator methodologies that combine statistical and qualitative information to assess water issues and rank the differing ‘needs’ of locations. However, due to limitations, we argue that indicator methodologies are best supported by a broader deliberative process of engagement, involving in-depth exploration of issues using inclusive and collective learning processes. In this paper, an integrative and deliberative process is described and applied to understand and evaluate watershed resources and management in the Tigum-Aganan watershed, Philippines. Collectively, local knowledge from stakeholders and quantitative information have been used in developing the water needs index, providing data and informing the selection of data sources for use in the index methodology. In subscribing to the exchange of descriptive narratives we achieve a greater degree of context dependence, transparency and stakeholder participation in the assessment process. Whilst our assessment of the usefulness of the composite methodology is subjective, we believe that the methodology shows great promise; in particular in supporting the emergence of collective action. [Copyright &y& Elsevier]

Summary: Future water management will shift from building new water supply systems to better operating existing ones. The variation of water values in time and space will increasingly motivate efforts to address water scarcity and reduce water conflicts. Hydro-economic models represent spatially distributed water resource systems, infrastructure, management options and economic values in an integrated manner. In these tools water allocations and management are either driven by the economic value of water or economically evaluated to provide policy insights and reveal opportunities for better management. A central concept is that water demands are not fixed requirements but rather functions where quantities of water use at different times have varying total and marginal economic values. This paper reviews techniques to characterize the economic value of water use and include such values in mathematical models. We identify the key steps in model design and diverse problems, formulations, levels of integration, spatial and temporal scales, and solution techniques addressed and used by over 80 hydro-economic modeling efforts dating back 45-years from 23 countries. We list current limitations of the approach, suggest directions for future work, and recommend ways to improve policy relevance. [Copyright &y& Elsevier]

• H-CMLM new method to empower the analysis of temporal rivers runoff behaviour. • H-CMLM is developed through the hybridization of MGLM and Causal Reasoning techniques. • H-CMLM is successfully applied to three Spanish basins with disparate features. • Results from modules are robust and shown through Dependence Mitigation Graph (DMG). • Outcome is very useful for the optimal dimensioning of hydraulic infrastructures. This paper describes the joint development of two different methods for temporal riveŕs runoff assessment. This is performed through a hybrid approach by means of Multivariate General Linear Models (MGLM; inspired by MLR as a statistical method), and Causal Reasoning (CR; as non-linear ones). This innovative methodological approach, named Hybrid Causal Multivariate Linear Modelling (H-CMLM), is mainly aimed to empower the analysis of temporal hydrological records behaviour. H-CMLM has been successfully applied to three different Spanish basins (Adaja, Mijares and Porma) which were chosen due to their disparate features. Results were divided in quantitative and qualitative. Numerical results show a very high level of equivalence between the average value of temporal dependence provided by MLM module and the continuous behaviour of temporal dependence computed by CR module and visualized through Dependence Mitigation Graph (DMG). This high coherent outcome from both modules makes the analysis much more robust from a stochastic hydrology point of view. Values for average temporal dependence are very useful for the optimal dimensioning of hydraulic infrastructures like reservoirs. Furthermore, given the annual scale of the analysis, water planning and management of several water uses such as domestic water supply, agriculture, industrial demands, among others, can be highly assisted by this new H_C-MLM method. [ABSTRACT FROM AUTHOR]

• Coherence between urban water and river basin management is needed in megacities. • A literature review on river basin and urban water management is conducted. • Rapprochement between IWRM/IRBM and IUWM/SUWM but scalar mismatch prevails. • Complexity of metropolitan areas is not addressed by water management literature. Due to rapid urbanization, population growth and economic drivers, megacities and metropolises around the world face increasing water challenges, such as water scarcity, degradation of water resources and water-related risks such as flooding. Climate change is expected to put additional stress on already strained metropolitan water management systems. Although there is considerable research on river basin management and on urban water management, there is hardly any on metropolitan water management. Similarly, as urban water generally emerges from and returns to river basins, it is surprising how little literature there is that explicitly connects these two spheres of governance. Hence this review paper addresses the: What does a review of the literature tell us about the overlap and reconciliation between the concepts of Integrated Water Resources/River Basin Management and Metropolitan/Urban Water Management, particularly in relation to megacities? Based on an extensive literature review, this paper concludes that the key differences between the two are in relation to their overarching framework, scope, inputs and outputs of water and in relation to dealing with extreme weather events. The literature review reveals how sustainable and integrated urban water management increasingly adopt principles and rhetoric from integrated water resource management, this has yet to translate into significant changing practices on the ground. Urban water management still often occurs independently of river basin issues. Achieving coherence between river basin management and sustainable/integrated urban water management is even more difficult in metropolises and megacities, because the latter consists of multiple political-administrative units. The article concludes that the scalar mismatch between river basin management and metropolitan/megacity water governance deserves much greater attention than it currently receives in the academic and policy debates. [ABSTRACT FROM AUTHOR]

• A tributary-comparison method to quantify the human influence on hydrological drought. • Establishing an indicator system for the selected natural reference tributary. • This method offers a useful supplement to existing research methods. • This method reduces the difficulty and subjectivity of existing methods. Quantifying the influence of human activities on hydrological drought is of great significance to sustainable water resource management, but it remains difficult. The key to solving this problem is determining how to scientifically select the natural reference tributary. On the basis of existing research, this paper puts forward a tributary-comparison method that combines the Drought Propagation Intensity Index (DPI) with the human activity index to preliminarily and quantitatively determine the natural reference tributary from among all tributaries and then quantify the influence of human activities on hydrological drought in other tributaries. The empirical research was carried out in the upper reaches of the Shiyang River in the eastern area of Qilian Mountain. The results showed that, firstly, at the annual and seasonal scales, the tributaries in the upper reaches of the Shiyang River changed from hydrological humidification to hydrological aridification, from west to east, from 1961 to 2016. On the whole, the hydrological aridification of Huangyang River in the central part was the most serious, but its hydrological drought duration and drought Intensity showed a downward trend at a monthly scale. Secondly, using the tributary-comparison method, Xiying River was quantitatively selected as the natural reference tributary, and the influence of human activities on hydrological drought in other tributaries was quantified. On the whole, human activities will reduce hydrological drought duration and enhance hydrological drought intensity. The empirical study further proved that the tributary-comparison method has strong applicability in multi-tributary areas with obvious differences in human activities and provides a useful supplement to existing research methods. According to this method, tributaries that are weakly affected by human activity (or not affected at all) can be selected, and the tributaries least affected by human activity can also be identified. On this basis, the influence degree and direction of human activities in other tributaries on hydrological drought can be quantified. [ABSTRACT FROM AUTHOR]

• CIRFs are useful for exploring risks of system failure under climate change. • Synthetic streamflow series are generated using SA and linked to climate conditions. • Logistic regression relates system responses to climate drivers. • System failure defined according to performance (reliability) and threshold. • LR model detects climate conditions which would require adaptation. Climate Impact Response Functions (CIRFs) can be useful for exploring potential risks of system failure under climate change. The performance of a water resource system can be synthesized through a CIRF that relates climate conditions to system behavior in terms of a specified threshold of deliveries to demands or environmental flow requirements. However, in highly regulated water resource systems this relationship may be quite complex, depending on storage capacity and system operation. In this paper we define a CIRF for these types of systems through a multivariable logistic regression (LR) model where a binary variable (system response) is explained by two continuous variables or predictors (precipitation and temperature). The approach involves generating multivariate synthetic inflow time series and relating them to specific climate conditions. Next, these inflows are used as inputs in a water management model, and the outcome is coded as a binary variable (failure or its absence) depending on selected vulnerability criteria. To identify the time span before the failure event in which climate variables are relevant, we characterized drought development stages through relative standardized indices. Mean values of precipitation and temperature for the selected time span are computed and used as explanatory variables through a LR model, which is validated using data from several climate models and scenarios. Results show that the predictive capacity of LR models is acceptable, so that they could be used as screening tools to detect challenging climate conditions for the system which would require adaption actions. [ABSTRACT FROM AUTHOR]

• Recharge sources of three groundwater aquifers have been quantified in Ejina Oasis by using EMMA. • Increase in river discharge into the Oasis can restore shallow groundwater levels. • Semi-confined groundwater levels continued to decline for over-exploited groundwater in MHR. • Lateral groundwater flow from the Qilian Mountain was impossible to recharge confined aquifer. • Effective integrated water management policies were suggested. The global expansion of irrigation-based agricultural practices is causing an overexploitation of groundwater resources. A thorough understanding of groundwater recharge processes is necessary for restoring groundwater and improving water resources management, especially in desert oasis aquifers in endorheic basins. In this paper, the Ejina Oasis in the downstream of Heihe River Basin was selected as the representative case for such an endeavor. Based on stable isotopes and end member mixing analysis, we found that the shallow groundwater was modern water, with 13% originating from local precipitation and 87% from river water infiltration. The semi-confined groundwater is a mixture of shallow groundwater (30%), lateral groundwater flowing from the middle Heihe River Basin (MHR; 52%), and confined groundwater (18%). Confined groundwater was old water formed in paleo-climatic humid and cold conditions. Shallow groundwater levels were restored substantially after implementation of the Ecological Water Diversion Project (EWDP) began in 2000 in the Heihe River Basin, but the semi-confined groundwater levels still declined slowly. These different responses to EWDP are attributed to the differences in primary recharge sources of the two aquifers. Because river water infiltration was the main sources of shallow groundwater, increases in river discharge into the Ejina Oasis resulted in increased shallow groundwater levels over a short time scale. Continued over-pumping of groundwater for irrigation in the MHR reduced lateral groundwater flow into the lower Heihe River Basin, which was the primary source of semi-confined groundwater. For successful groundwater restoration and maintenance of groundwater for the future, EWDP implementation must integrate water management of river water and groundwater diversion across the whole basin. Our results can provide useful information on policy decision makers for sustainable use of water resources in the oases of other similar watersheds around the world. [ABSTRACT FROM AUTHOR]

• A framework for systematic analysis of community-based monitoring initiatives. • The framework consists of five generic dimensions across all initiatives. • It distinguishes between contextual and initiative-related aspects. • It can be used for context analysis, processes evaluation and impact assessment. Community-based monitoring of water and environmental resources is believed to have the potential to help produce more or better water and environmental data, increase public participation in environmental monitoring, respond to issues of common community concern and enhance informed, democratic and transparent environmental decision making. Despite these perceived outcomes, initial and long term engagement of different stakeholders with community-based monitoring activities remains a challenge. Successful establishment of these initiatives has proven to be complex and there is little evidence that community-based monitoring projects have an impact on environmental or water resources management processes, or a legacy beyond their funding period. Whereas much attention is being paid to promoting community-based monitoring as a tool for producing more or better water or environment-related data, there is little conceptual understanding of how to critically analyze and understand the features and functioning of these initiatives. Therefore we do not know whether, or to what extent, these initiatives deliver on their perceived potentials. Thus, it is essential to learn from past experiences and critically document, analyze and understand factors that might influence the establishment, functioning and outcomes of community-based monitoring initiatives. Based on the review of a large body of literature in the fields of community-based monitoring, Citizen Science and affiliated fields of research, combined with the empirical evidence from a number of major EU-funded community-based monitoring projects, this paper introduces a framework that can be utilized to analyze the dynamics underlying the establishment and functioning of community-based monitoring initiatives. The distinction between five different dimensions, consisting of 22 internal and context-related factors, is a unique feature of this framework that broadens its applicability and makes it suitable for 'Context analysis', 'Process evaluation' and 'Impact assessment' of the initiatives. The introduced framework is therefore called the CPI framework in short. [ABSTRACT FROM AUTHOR]

• Temperature trends alter rainfall uniformity by modifying characteristics of rainfall events. • A significant relationship between rainfall uniformity and low rainfall intensity is observed. • Rainfall uniformity, high and low intensity of rainfall show a decreasing order of sensitivity to annual mean temperature. Understanding response of temporal distribution, timing, frequency and amount of high and low intensity rainfall to warming is important in water resources management. In this paper, Relative Entropy is used to investigate the spatial variability and change in uniformity of rainfall distribution over India. Temporal trends in atmospheric temperature can alter the frequency and amount of high and low intensity rainfall events, which influence the uniformity of rainfall distribution. The study is divided into two time periods, 1951–1980 and 1981–2010 based on time trend in annual mean temperature. The sensitivity of rainfall uniformity and high and low intensity rainfall events to annual mean temperature and the degree of coherence between them are investigated. The uniformity of rainfall distribution shows a significant spatial variability. Significant changes are observed in both the amount and timing of rainfall across India. A significant association between rainfall uniformity and low intensity of rainfall is observed in the recent past over a larger aerial extent compared to the distant past. It is concluded that rise in temperature modifies both high and low intensity rainfall events, thus altering the uniformity in rainfall distribution. A regionally varied strength of coherence between rainfall uniformity and high and low intensity rainfall is observed which may be due to regionally dependent soil moisture-precipitation feedbacks. [ABSTRACT FROM AUTHOR]