Global water resources modeling with an integrated model of the social-economic-environmental system

Awareness of increasing water scarcity has driven efforts to model global water resources for improved insight into water resources infrastructure and management strategies. Most water resources models focus explicitly on water systems and represent socio-economic and environmental change as external drivers. In contrast, the system dynamics-based integrated assessment model employed here, ANEMI, incorporates dynamic representations of these systems, so that their broader changes affect and are affected by water resources systems through feedbacks. Sectors in ANEMI therefore include the global climate system, carbon cycle, economy, population, land use and agriculture, and novel versions of the hydrological cycle, global water use and water quality. Since the model focus is on their interconnections through explicit nonlinear feedbacks, simulations with ANEMI provide insight into the nature and structure of connections between water resources and socio-economic and environmental change. Of particular interest to water resources researchers and modelers will be the simulated effects of a new water stress definition that incorporates both water quality and water quantity effects into the measurement of water scarcity. Five simulation runs demonstrate the value of wastewater treatment and reuse programs and the feedback-effects of irrigated agriculture and greater consumption of animal products.     

Wastewater reclamation and reuse in Eureau countries

Eureau is the Union of most National Associations of Water Suppliers and Wastewater Services in Europe. Most northern Eureau countries have abundant water resources. There, the need for extra supply through the reuse of treated wastewater is not a priority, but the protection of the receiving environment is considered important. The situation is different in the southern Eureau countries, where the additional resources brought by wastewater reuse can bring significant advantages to agriculture (e.g. crop irrigation) and tourism (e.g. golf course irrigation). There, wastewater is reused but under very diverse regulatory environments. Therefore, considering its various potential benefits (protection of water resources, prevention of coastal pollution, recovery of nutrients for agriculture, augmentation of river flow, savings in wastewater treatment, groundwater recharge, and sustainability of water resource management, etc.), wastewater reclamation and reuse can be applied to the advantage of both northern and southern Eureau countries. In order to take advantage of its full potential, Eureau would like to become involved in setting up international best practices and guidelines related to the reuse of treated wastewater. Such criteria and/or guidelines should contribute to a better management of water resources, a better protection of public health and of the environment and to a more sustainable development. Reclaimed wastewater is a reliable source of water that must be taken into account in formulating a sustainable water policy. To encourage wastewater reclamation and reuse in all Eureau countries and to establish its safe practice, European guidelines for most applications must be developed.     

Livestock wastewater treatment by a mangrove pot-cultivation system and the effect of salinity on the nutrient removal efficiency

The present investigation compared the capacity of greenhouse pot-cultivation systems under two salinity conditions (freshwater and saline water) with two mangrove species (Bruguiera gymnorrhiza and Kandelia candel) to remove nutrients from livestock wastewater. During the whole treatment period there were relatively stable leachate TOC concentrations for wastewater-treated pots. Leachate NH4(+)-N concentration of B. gymnorrhiza pots was generally lower than that of K. candel pots. Leachate PO4(3-)-P concentration of pots receiving wastewater under freshwater condition was higher than that under saline water condition. Soil inorganic N content was more than two times higher for the wastewater treatments than that for the controls under low salinity condition and slower rate of increase under saline water condition. Soil P nutrients of both total and extractable inorganic forms significantly increased for both systems due to the discharges of livestock wastewater under both salinity conditions. The rate of increase in P contents for plants receiving livestock wastewater was 1-4 times that of the controls, much more than that in N contents (0.04-1.30 times). N nutrient removal efficiencies were 84.3% (65.6% by soil and 18.7% by plant) and 95.5% (32.2% by soil and 63.4% by plant), respectively by Kandelia candel and B. gymnorrhiza pot-cultivation systems under freshwater condition. Under saline water condition, N nutrient removal efficiencies by K. candel and B. gymnorrhiza pot-cultivation systems were 92.7% (80.7% by soil and 12.0% by plant) and 98.0% (67.6% by soil and 30.3% by plant), respectively. P nutrient removal efficiencies by K. candel and B. gymnorrhiza systems under freshwater condition were 79.2% (76.6% by soil and 2.6% by plant) and 91.8% (88.2% by soil and 3.6% by plant), respectively. The corresponding values were 88.0% (84.2% by soil and 3.8% by plant) and 97.8% (95.9% by soil and 1.9% by plant) under saline water condition.     

Optimal Location of Wells for Storage and Recovery of Surplus Desalinated Water in Coastal Aquifers

Storage of water in aquifers using injection wells is an efficient way for utilizing excess desalinated water in arid regions. In this investigation we estimate the benefits of optimally recharging seasonal surplus desalinated water into a strategic coastal aquifer already benefitting from natural recharge of flash-floods water by a recharge dam. Since, usually the buyers of desalinated water commit to purchase surplus desalinated water under take-or-pay contracts, any attempt in utilizing the paid water is beneficial. Coastal cities are observing an increased urbanization leaving limited space for aquifer recharge infrastructure. In order to determine the optimal location of wells and maximize the use of surplus desalinated water available in winter period, a decision tool combining a numerical groundwater flow simulation model (MODFLOW) with an optimization model is developed. The results of this study show that increasing the number of wells from the existing 45 wells to 173 would allow storing 31.4 million cubic meter per year of excess desalinated water into the aquifer that can be used during later during summer months. The net benefit would reach US$55 million/year while the cost of drilling the new wells is US$5.11 million.     

Performance Evaluation of a Full‐Scale Extended Aeration System in Al‐Bireh City,Palestine

Major challenges attributed to dysfunctional wastewater treatment facilities in developing countries include lack of commitment and poor informed decision making by the higher municipal administration. This paper presents how process monitoring and control during full scale operation ensures sustainability of civic infrastructures like Al‐Bireh wastewater treatment plant (AWWTP). It is written from the perspective of practical process selection to evaluate the performance of AWWTP, a single‐sludge nitrification–denitrification process with aerobic sludge stabilization. Process monitoring data (July 2000–April 2007) from available monthly operating reports were analyzed and evaluated. Additional data on microbiological analysis and information about facility unit operations were gathered through review of published local literature and interviews with AWWTP personnel. Influent and effluent data evaluated were the chemical oxygen demand (COD), biological oxygen demand (BOD), total nitrogen (TN), and total phosphorus (TP). Despite annual and seasonal variations in AWWTP influent for COD, BOD, TN, and TP, the Palestinian wastewater reuse requirements for restricted irrigation were met. Process design and proper facility operation have direct impacts on effluent quality. The study concludes that regardless of the design capacity and process type, adequate administrative and operational management dictate the sustainability of AWWTP and reuse schemes.     

Analysis of Effective Efficiency in decision making for irrigation interventions

Multiple stresses are putting great pressure on water resources systems. Population growth, climate change, prosperity, energy production, food crisis, and water governance are among the factors straining water resources. Decision makers from rich to poor countries and from commercial to non-governmental organisations are struggling to devise schemes to adapt to these stressed water conditions. Better efficiency for water resources systems, and particularly irrigation systems, is recommended as one of the most important responses to climate change, unsustainable development, and water shortage. However, using certain efficiencies such as Classical Efficiency caused systems not to perform according to decision makers?? objectives. Effective Efficiency is a robust composite indicator that includes in its formulation both a flow weight, taking into account the leaching fraction, and reuse of return flows. Classical Efficiency is defined as the percentage of the diversion consumed beneficially, such as by crop evapotranspiration. Effective Efficiency, on the other hand, is defined as the ratio of beneficial consumptive use to total consumption, expressed as a percentage. In this paper, a normalised and non-dimensional form of Effective Efficiency is developed and necessary constraints for its successful application are explained. These constraints express water balance, flow weights and their thresholds, water reuse, and total consumptive use. Basic guidelines are proposed for better decision making in determining possible interventions for improving Effective Efficiency. This is done by analysing its domain through analytical and graphical methods. Three real cases are considered, namely, Imperial Irrigation District and Grand Valley irrigation systems in the United States and Nile Valley in upper Egypt. Three-dimensional sensitivity analysis is performed on Effective Efficiency and its variables using the three cases. This leads to an examination of the validity of the analysis and to suggestions for better intervention options. Meanwhile, it is also shown why Classical Efficiency should be used with care.     

Analyzing urban water supply through an acceptability-index-based interval approach

Incorporation of uncertainties within an urban water supply management system has been a challenging topic for many years. In this study, an acceptability-index-based two-step interval programming (AITIP) model was developed for supporting urban water supply analysis under uncertainty. AITIP improved upon the traditional two-step interval programming (TIP) through incorporating the acceptability level of constraints violation into the optimization framework. A four-layer urban water supply system, including water sources, treatment facilities, reservoirs, and consuming zones, was used to demonstrate the applicability of proposed method. The results indicated that an AITIP model was valuable to help understand the effects of uncertainties related to cost, constraints and decision maker’s judgment in the water supply network, and capable of assisting urban water managers gain an in-depth insight into the tradeoffs between system cost and constraints-violation risk. Compared with TIP, the solutions from AITIP were of lower degree of uncertainty, making it more reliable to identify effective water supply patterns by adjusting decision variable values within their solution intervals. The study is useful in helping urban water managers to identify cost-effective management schemes in light of uncertainties in hydrology, environment, and decisions. The proposed optimization approach is expected to be applicable for a wide variety of water resources management problems.     

Modelling hydrological response to a fully‐monitored urban bioretention cell

Municipalities and agencies use green infrastructure to combat pollution and hydrological impacts (e.g., flooding) related to excess stormwater. Bioretention cells are one type of infiltration green infrastructure intervention that infiltrate and redistribute otherwise uncontrolled stormwater volume. However, the effects of these installations on the rest of the local water cycle is understudied; in particular, impacts on stormwater return flows and groundwater levels are not fully understood. In this study, full water cycle monitoring data were used to construct and calibrate a two‐dimensional Richards equation model (HYDRUS‐2D/3D) detailing hydrological implications of an unlined bioretention cell (Cleveland, Ohio) that accepts direct runoff from surrounding impervious surfaces. Using both preinstallation and postinstallation data, the model was used to (a) establish a mass balance to determine reduction in stormwater return flow, (b) evaluate green infrastructure effects on subsurface water dynamics, and (c) determine model sensitivity to measured soil properties. Comparisons of modelled versus observed data indicated that the model captured many hydrological aspects of the bioretention cell, including subsurface storage and transient groundwater mounding. Model outputs suggested that the bioretention cell reduced stormwater return flows into the local sewer collection system, though the extent of this benefit was attenuated during high inflow events that may have exhausted detention capacity. The model also demonstrated how, prior to bioretention cell installation, surface and subsurface hydrology were largely decoupled, whereas after installation, exfiltration from the bioretention cell activated a new groundwater dynamic. Still, the extent of groundwater mounding from the cell was limited in spatial extent and did not threaten other subsurface infrastructure. Finally, the sensitivity analysis demonstrated that the overall hydrological response was regulated by the hydraulics of the bioretention cell fill material, which controlled water entry into the system, and by the water retention parameters of the native soil, which controlled connectivity between the surface and groundwater.     

Identification of optimal strategies for agricultural nonpoint source management in Ulansuhai Nur watershed of Inner Mongolia,China

In this study, an environmental-friendly modeling system was developed and applied to an agriculture nonpoint source (AGNPS) management in Ulansuhai Nur watershed. In this system, water environmental capacity, credibility-based chance-constrained programming (CCCP), and AGNPS optimization models were integrated into a general modeling framework. It could be used to calculate water environmental capacity of total nitrogen and total phosphorus in Ulansuhai Nur watershed, which could consequentially provide input data for the developed AGNPS optimization model. Also, the inherent uncertainties in estimating water environmental capacities that can be expressed as possibilistic distributions were reflected and addressed based on computational results of three widely used methods. Such uncertainties were consequentially transferred to the proposed CCCP model based on the adoption of multiple credibility satisfactory levels, significantly facilitating objectivity reflection of decision alternatives. The developed modeling system was then applied to Ulansuhai Nur watershed of Inner Mongolia, a semi-arid river basin in northwestern China. Optimal strategies for AGNPS management in Ulansuhai Nur watershed were generated with consideration of the maximum total agricultural income under multiple policy scenarios. The results showed that the total agricultural income would increase with point source pollution being cut down, and would decrease with rising credibility levels, representing decreasing system violation risks. It was indicated that the higher of total nitrogen/phosphorus discharge being less than water environmental capacity of Ulansuhai Nur, the lower the total agriculture incomes. The proposed methods could help decision makers establish various production patterns with cost-effective agriculture nonpoint source management schemes in the basin of Ulansuhai Nur, and gain in-depth insights into the trade-offs between total agricultural incomes and system reliabilities.     

Evaluating water reuse applications under uncertainty: generalized intuitionistic fuzzy-based approach

Water reuse is a viable option to increase urban water supply, especially under new realities of climate change and increasing anthropogenic activities. A sustainable water reuse application should be cost-effective and have acceptable health risk to consumers. Water reuse application evaluation is complex because data acquisitions are usually associated with the problems of uncertainty, hesitancy, and parameterization. In this paper, a generalized intuitionistic fuzzy soft set (GIFSS)-based decision support framework is proposed to provide an effective approach to describe uncertainty and hesitancy in an intuitionistic fuzzy number. In addition, the modified measures of comparison and similarity are proposed to compare water reuse applications. Then, the proposed framework is applied to the City of Penticton (British Columbia, Canada) to evaluate seven water reuse applications. The evaluation results show that the applications of garden flower watering and public parks watering are the most preferred alternatives, which are consistent with the existing practice in the city. Furthermore, the results are highly affected by the generalized parameter and the weights of evaluation criteria. Both the comparison measure-based and similarity measure-based evaluations within the same GIFSS-based framework produce consistent results, indicating an applicable and efficient methodology.     

A scenario-based water conservation planning support system (SB-WCPSS)

In this study a water consumption model is built into a scenario-based planning support system (SB-WCPSS). The SB-WCPSS consists of four components—(1) a model input graphic user interface, (2) a community spatial database, (3) a set of drinking water consumption models, and (4) output display. The SB-WCPSS is implemented with a commercial planning support system software package—CommunityViz. The model is applied using data in Cincinnati, Ohio, USA to demonstrate the scenario development. In the application, water consumption consists of land use based indoor, turf, and pool water usages. Climate change is reflected in monthly temperature and precipitation. By specifying anticipated future land uses and associated water consumption rates, temperature, and precipitation, SB-WCPSS users can analyze and compare water consumptions under various scenarios, using maps, graphs, and tables. Parcel-based daily water consumptions were computed and summarized spatially by neighborhood, block group, or land use type. The results demonstrate that water conservation strategies, such as xeriscape, can reduce turf water usage. Indoor water consumption depends on the number of people who use water and how they use water. The study shows that the SB-WCPSS structure is sound and user friendly. Future improvement will be on enhancing various components, such as using parcel-based data and more robust water consumption models. The system may be used by water resource managers and decision makers to adapt water resources (e.g., watersheds and infrastructure) to climate change and demographic and economic development.     

Surveillance of Invasive Bacterial Pathogens and Human Enteric Viruses in Wastewater Final Effluents and Receiving Water Bodies – a Case Study from Durban,South Africa

The physico‐chemical characteristics and microbial composition of the final effluents of two municipal wastewater treatment plants in South Africa were assessed between July and September 2009. The impact of the treated final effluents on the receiving water bodies was also evaluated. The temperature across all sampling points ranged between 14 and 22°C, while pH varied from 6.9 to 7.6. High levels of turbidity, chemical oxygen demand (COD), ammonia, nitrate, nitrite and orthophosphate (PO₄) were observed in many cases. Turbidity of the samples was in the range of 2.2–288.6 NTU. The concentrations (mg/L) of other physico‐chemical parameters are as follows: COD (9.33–289); ammonia (0.000340–45.4); nitrate (0.062–539); nitrite (0.021–22.6); PO₄ (5.3–33.2). The microbial quality of the effluents discharged from the plants did not comply with the limits set by the South African guidelines with respect to pathogens such as Salmonella, Shigella, Escherichia coli, total coliform, faecal coliform, enterococci, faecal streptococci, and viral particles for effluents intended for discharge into receiving watersheds. This study revealed an undesirable impact on the physico‐chemical and microbial qualities of the receiving water bodies as a result of the discharge of inadequately treated effluents from the wastewater treatment facilities. This poses a health risk to several rural communities which rely on the receiving water bodies primarily as their sources of domestic water and recreational purposes. There is therefore a need for the intervention of appropriate regulatory agencies in South Africa to ensure compliance of treatment facilities with wastewater effluent quality standards.     

Physico‐Chemical and Bacterial Characteristics of Water Quality in Three Villages West of Lake Nasser,Egypt

The present study aims to investigate physico‐chemical and bacterial characteristics of Nasser Lake water and houses drinking water, as well as fish cultures and its wastewater, in three villages west of Lake Nasser, Egypt. Fifteen representative water samples (Nasser Lake, different drinking water, fish cultures, and wastewater sources) were collected from three villages (Garf Hussein, Bashaier, and Kalabsha) in the west of Lake Nasser. Physico‐chemical, total viable counts, and bacterial qualification of water were achieved. The obtained results indicated that the produced water, supposed to be for domestic use in the three villages, contained all the tested organisms. The investigated water samples of the lake and drinking water in the selected three villages are supposed to be chemically safe according to World Health Organization and to Egyptian standards for drinking water. Water pollution index (WPI) was used in this study and the result concluded that for irrigation canals from the lake to the agriculture site, fish cultures (both concrete and earth pond systems), and drainage canal of fish ponds need to be treated before it is discharged to the lake. It is better to reuse it after treatment for agricultural purposes or recycled it to the fish cultures.     

Optimization and capacity expansion of a water distribution system

This paper develops an iterative procedure for capacity expansion studies for water distribution systems. We propose a methodology to analyze an existing water distribution system and identify the potential bottlenecks in the system. Based on the results, capacity expansion alternatives are proposed and evaluated for improving the efficiency of water supply. The methodology includes a network flow based optimization model, four evaluation indices, and a series of evaluation steps. We first use a directed graph to configure the water distribution system into a network. The network flow based model optimizes the water distribution in the system so that different expansion alternatives can be evaluated on a comparable basis. This model lends itself to linear programming (LP) and can be easily solved by a standard LP code. The results from the evaluation tool help to identify the bottlenecks in the water distribution system and provide capacity expansion alternatives. A useful complementary tool for decision making is composed of a series of evaluation steps with the bottleneck findings, capacity expansion alternatives, and the evaluation of results. We apply the proposed methodology to the Tou-Qian River Basin, located in the northern region of Taiwan, to demonstrate its applicability in optimization and capacity expansion studies.     

Numerical Modeling of Unsaturated Flow in Wastewater Soil Absorption Systems

It is common practice in the United States to use wastewater soil absorption systems (WSAS) to treat domestic wastewater. WSAS are expected to provide efficient, long-term removal of wastewater contaminants prior to ground water recharge. Soil clogging at the infiltrative surface of WSAS occurs due to the accumulation of suspended solids, organic matter, and chemical precipitates during continued wastewater infiltration. This clogging zone (CZ) creates an impedance to flow, restricting the hydraulic conductivity and rate of infiltration. A certain degree of clogging may improve the treatment of wastewater by enhancing purification processes, in part because unsaturated flow is induced and residence times are significantly increased. However, if clogging becomes excessive, the wastewater pond height at the infiltrative surface can rise to a level where system failure occurs. The numerical model HYDRUS-2D is used to simulate unsaturated flow within WSAS to better understand the effect of CZs on unsaturated flow behavior and hydraulic retention times in sandy and silty soil. The simulations indicate that sand-based WSAS with mature CZs are characterized by a more widely distributed flow regime and longer hydraulic retention times. The impact of clogging on water flow within the silt is not as substantial. For sand, increasing the hydraulic resistance of the CZ by a factor of three to four requires an increase in the pond height by as much as a factor of five to achieve the same wastewater loading. Because the degree of CZ resistance directly influences the pond height within a system, understanding the influence of the CZ on flow regimes in WSAS is critical in optimizing system design to achieve the desired pollutant-treatment efficiency and to prolong system life.     

Designing river water quality policy interventions with scarce data: the case of the Middle Tagus Basin,Spain

ABSTRACT

Anthropic pressures deteriorate river water quality, so authorities need to identify their causes and define corrective actions. Physically based water quality models are a useful tool for addressing physicochemical pollutants, but they must be calibrated with an amount of data that is often unavailable. In this study, we explore the characterization of a model to design corrective interventions in a context of sparse data. A calibration indicator that is both simple and flexible is proposed. This approach is applied to the Middle Tagus Basin in central Spain, where the physicochemical concentration of pollutants is above legal standards. We quantify the effects of the main existing pressures (discharge from wastewater treatment plants, agricultural diffuse pollution and a major inter-basin water transfer) on the receiving waters. In particular, the study finds that wastewater treatment plant effluent concentrations should be reduced to up to 0.65 mg/L of ammonium and 0.55 mg/L of phosphate to achieve the environmental goals. We propose and prioritize a set of policy actions that would contribute to the good status of surface water bodies in the region.     

System dynamics modeling of transboundary systems: the bear river basin model

System dynamics is a computer-aided approach to evaluating the interrelationships of different components and activities within complex systems. Recently, system dynamics models have been developed in areas such as policy design, biological and medical modeling, energy and the environmental analysis, and in various other areas in the natural and social sciences. The Idaho National Engineering and Environmental Laboratory, a multipurpose national laboratory managed by the Department of Energy, has developed a system dynamics model in order to evaluate its utility for modeling large complex hydrological systems. We modeled the Bear River basin, a transboundary basin that includes portions of Idaho, Utah, and Wyoming. We found that system dynamics modeling is very useful for integrating surface water and ground water data and for simulating the interactions between these sources within a given basin. In addition, we also found that system dynamics modeling is useful for integrating complex hydrologic data with other information (e.g., policy, regulatory, and management criteria) to produce a decision support system. Such decision support systems can allow managers and stakeholders to better visualize the key hydrologic elements and management constraints in the basin, which enables them to better understand the system via the simulation of multiple "what-if" scenarios. Although system dynamics models can be developed to conduct traditional hydraulic/hydrologic surface water or ground water modeling, we believe that their strength lies in their ability to quickly evaluate trends and cause-effect relationships in large-scale hydrological systems, for integrating disparate data, for incorporating output from traditional hydraulic/hydrologic models, and for integration of interdisciplinary data, information, and criteria to support better management decisions.     

Planning water resources management systems using a fuzzy-boundary interval-stochastic programming method

In this study, a fuzzy-boundary interval-stochastic programming (FBISP) method is developed for planning water resources management systems under uncertainty. The developed FBISP method can deal with uncertainties expressed as probability distributions and fuzzy-boundary intervals. With the aid of an interactive algorithm woven with a vertex analysis, solutions for FBISP model under associated α-cut levels can be generated by solving a set of deterministic submodels. The related probability and possibility information can also be reflected in the solutions for the objective function value and decision variables. The developed FBISP is also applied to water resources management and planning within a multi-reservoir system. Various policy scenarios that are associated with different levels of economic consequences when the pre-regulated water-allocation targets are violated are analyzed. The results obtained are useful for generating a range of decision alternatives under various system conditions, and thus helping decision makers to identify desired water resources management policies under uncertainty.     

Impurity effect on clear water evaporation: toward modelling wastewater evaporation using ANN,ANFIS-SC and GEP techniques

The growing shortage of freshwater resources and increasing environmental awareness give rise to the use of treated wastewater as an alternative resource for water supply. Accurate estimation of wastewater evaporation (WWE), as the main cause of water losses, is necessary for proper water resources management. Unfortunately, few studies have focused on modelling WWE despite its vital importance. This study investigates the ability of gene expression programming (GEP), adaptive neuro-fuzzy inference system (ANFIS) and artificial neural networks (ANN) techniques to estimate WWE as a function of variables including wastewater properties, clear water evaporation and climatic factors. The study uses measured data from an experiment conducted in Neishaboor municipal wastewater treatment plant, Iran. Results indicate that the ANN model is superior among the three methods, and also demonstrates higher accuracy when compared with those of a dimensional analysis model using the F-test statistic.     

Scenario-based water resources planning for utilities in the Lake Victoria region

Urban areas in the Lake Victoria (LV) region are experiencing the highest growth rates in Africa. As efforts to meet increasing demand accelerate, integrated water resources management (IWRM) tools provide opportunities for utilities and other stakeholders to develop a planning framework comprehensive enough to include short term (e.g. landuse change), as well as longer term (e.g. climate change) scenarios. This paper presents IWRM models built using the Water Evaluation And Planning (WEAP) decision support system, for three towns in the LV region – Bukoba (Tanzania), Masaka (Uganda), and Kisii (Kenya). Each model was calibrated under current system performance based on site visits, utility reporting and interviews. Projected water supply, demand, revenues and costs were then evaluated against a combination of climate, demographic and infrastructure scenarios up to 2050. Our results show that water supply in all three towns is currently infrastructure limited; achieving existing design capacity could meet most projected demand until 2020s in Masaka beyond which new supply and conservation strategies would be needed. In Bukoba, reducing leakages would provide little performance improvement in the short-term, but doubling capacity would meet all demands until 2050. In Kisii, major infrastructure investment is urgently needed. In Masaka, streamflow simulations show that wetland sources could satisfy all demand until 2050, but at the cost of almost no water downstream of the intake. These models demonstrate the value of IWRM tools for developing water management plans that integrate hydroclimatology-driven supply to demand projections on a single platform.