Unmet Water Demand Research Articles

Assessment on Water Resource Management for Sedawgyi Dam: A WEAP Analysis Approach

This study employs the Water Evaluation and Planning (WEAP) system to analyze water resource management for the Sedawgyi Dam in Myanmar. The research integrates hydrological data, demand projections, and infrastructure information to simulate current and future water scenarios. Key steps include model setup, calibration, scenario development, and analysis. The results indicate that Mandalay City's highest domestic water demands are in Chanmyatharzi and Aungmyaetharzan townships, with agricultural water demands peaking in Mattaya township. The reference scenario highlights a significant domestic water supply shortfall, meeting only 10% of the demand, while agricultural demands are nearly fully met. The study underscores the urgent need for improved water management strategies to address rising unmet water demands, particularly for domestic use, to ensure sustainable water resource allocation in the region.

Water resources management under climate change and anthropogenic pressure in the upper Bandama catchment in Northern Côte d'Ivoire

ABSTRACT The upper Bandama basin at Badikaha in the North of Côte d'Ivoire, subject to climate change, has recorded a rapid population growth that significantly affects water availability. This study applies the water evaluation and planning (WEAP) system model to explore how the water resources available currently can meet people's needs in the future, mainly for irrigation, mining activities, rural and urban water supply and cattle breeding. The outputs from two regional climate models RACMO 22T and CCLM 4-8-17 under representative concentration pathway (RCP) 4.5 and RCP 8.5 scenarios were used for the climate change impact assessment. Results predict an increase in mean annual temperature by 1.5°C while precipitation could decrease by 21% by 2090. The climate model outputs coupled with the WEAP model show that unmet water demand estimated to 50 million m3 in 2020 could reach 115 million m3 in 2050. Nevertheless, climate change mitigation scenarios by the WEAP model, including the implementation of dams, boreholes and the hydraulics infrastructure improvement reveal that water scarcity could be reduced significantly in the catchment.

Projecting hydrological response to climate change and urbanization using WEAP model: A case study for the main watersheds of Bicol River Basin, Philippines

Study regionBicol River Basin, Philippines Study focusThe study investigated the impact of climate change and urbanization on water resources in the Philippines. It used Water Evaluation and Planning (WEAP) software and climate forecasts from eight Global Circulation Models (GCMs) to assess the nation's water balance, focusing on two sensitive watersheds: Libmanan-Pulantuna (LPW) and Quinali (QW). The study projects water availability in these areas by creating climate-urbanization scenarios. Furthermore, our endeavor aims to provide insight into the complexities of hydrological processes within traditionally under-observed regions, serving as a blueprint for future environmental planning and sustainable water management in the Philippines and beyond. New hydrological insightsThe study's simulated streamflow matches observed data (R2: 0.70–0.85, NSE: 0.57–0.67) and indicates warming trends and variable precipitation in both watersheds. Rising water demand in domestic and industrial sectors contrasts with a decline in agriculture due to land conversion. QW faces increased water demands from urbanization, while LPW has lower unmet water demand. Low Land Decline scenarios indicate consistent water scarcity in agriculture, while High Land Decline scenarios predict a decrease by 2100. Urbanization significantly impacts future water stress more than climate change, with reduced agricultural land generally associated with lower water stress. Conversely, climate change exacerbates unmet demand issues in domestic and industrial development cases. Due to diminishing agricultural land, both watersheds are expected to transition from water-deficient to water-surplus regions by the end of the century. However, immediate action is crucial to address current water demands, particularly in the severely water-deficient Quinali Watershed.

Addressing the Water-Energy-Food Nexus in the context of climate change: The case of Bagré dam in Burkina Faso

The water-energy-food (WEF) nexus concept highlights the interdependencies between water, energy, and food resources. Assessing these interdependencies can lead to a better understanding and their exploitation to improve people's access to water, energy, and food. This study aims to highlight the links between the water resource and the current and future water requirements for agricultural and hydropower production in the context of climate change. The bagré dam which is a multi-usage reservoir located in Burkina Faso is considered as the case study. This dam is used for agricultural production, livestock, and hydroelectricity production. To achieve this objective, the surface water resources of the study area and the different water uses have been first estimaded. Then, a model has been developed and implemented using the Water Evaluation And Planning (WEAP) tool, with the reference year 2020. Finally, the developed model was used to study four relevant plausible scenarios in the Bagré area up to 2050, namely: (1) expansion of irrigated schemes, (2) the drinking water needs of a neighbouring town, (3) climate change effects on the dam's water capacity, and (4) combinaison of the three other scenarios. The results show that all the water requirements for different uses are fully met for all the scenario except the combined scenario by 2050. For this last scenario, the unmet water demands reach up to 100 % specially during dry season. So, to improve the coverage rate of water demands for the combined scenario, it is crucial to explore other alternatives such as the use of groundwater and the implementation of best practices in agronomic management.

Factors impacting water quality and quantity in rapidly expanding urban areas based on the DPSIR model: experiences and challenges from Addis Ababa City, Ethiopia.

Due to the increasing pressures of global change, such as urbanization, climate change, population growth, and socioeconomic changes, cities around the world are facing significant water challenges, both in terms of supply and quality. This emphasizes the need for concerted effort to manage water supplies effectively for sustainable development. The driver, pressure, state, impact, and response (DPSIR) model was applied in this study to determine the underlying causes of Addis Ababa's water supply and quality issues. Field observations, key informant interviews, and previously published reports were used to identify these variables, impacts, and coping mechanisms. The model suggests that issues with urban water are caused by inadequate waste management, fast urbanization, climate change, sociodemographic shifts, economic challenges, changes in land use and land cover, and institutional pressures. As a result, aquatic ecosystems endure damage and there is also an increase in water-related diseases and unmet water demand. Some of the responses to these effects include using bottled water, digging boreholes, harvesting rainwater, planting trees, and soliciting funds. The study concludes by recommending an integrated approach to managing the risks of declining water quality and shortage. This study will advance the important empirical understanding of how urban water supply and quality are impacted by environmental stresses on a global scale. It will also positively impact the development of sustainable water management policies and practices.

Assessing the impact of Water Resource Development: The Case of Dhidhessa River Basin, Ethiopia

Freshwater scarcity is becoming more of a concern as populations grow and economic demands increase. The Dhidhessa River, a critical source for the Abbay River basin, is under pressure. This study looked at how water resource development projects and changes in water flow impact the basin. Water flow was simulated using WEAP model (software), which took into account various water sources and needs. The study also looked at crop water requirements and the level of flow alteration. Future water demand scenarios were created. The first, scenario considered population growth, with projections indicating that unmet water demand would increase significantly by 2050. The second scenario focused on irrigation expansion, which resulted in a significant increase in unmet water demand. These findings demonstrate the impact of both population growth and water resource development for irrigation activities. The study further investigated how flow alterations affect the river. While most months saw little change, a particular section near Dembi was discovered to be more vulnerable. Remarkably, allocating water specifically for environmental needs, in addition to human demands, resulted in a decrease in unmet water demand. This suggests that prioritizing environmental flow management is critical for long-term water use in the Dhidhessa River basin.

Simulation of current and future water demands using the WEAP model in the Annaba province, Northeastern Algeria: a case study

Abstract The Annaba province in Algeria is currently facing significant challenges due to water shortages and intermittent water distribution. This study utilizes the Water Evaluation And Planning (WEAP) system to assess present and future water supply and demands in Annaba province, Algeria. Five scenarios, including a reference, climate change, desalination, leakage reduction, and water reuse, are evaluated. The analysis reveals that the region faces significant water shortages and intermittent distribution, with projected annual water demand reaching 148 Mm3 by 2070. Climate change amplifies the demand by 8%, resulting in a projected water demand of 151 Mm3 by 2070. The industrial sector exhibits the highest unmet water demand, while the domestic and agricultural sectors also face challenges. Alternative scenarios, such as water efficiency and desalination, offer potential for eliminating industrial unmet water demand. Scenario 5 (managed aquifer recharge) reduces industrial unmet water demands by 36% to 23 Mm3 by 2070, while scenario 4 (leakage reduction and water reuse) decreases unmet domestic demands to 24 Mm3. This study emphasizes the need for water management strategies including efficient water use, infrastructure investment, public education on conservation and reuse, and industry adoption of water-saving technologies. Overall, this study addresses the difficulties and challenges associated with water scarcity in Annaba province.

Investigation of water allocation using integrated water resource management approaches in the Zayandehroud River basin, Iran

The Zayandehroud River is the largest river in the Gavkhouni basin, Iran. Water management in this basin is beset by poor water-allocation policies that do not adequately meet diverse demands (potable, agriculture, industry, and environmental demands). The Gavkhouni basin suffers from water scarcity and unmet water demands; especially with respect to environmental requirements. Water allocation considering appropriate priorities for all demands would be a major improvement for environmental protection in the Gavhouni basin. The application of the environmental flow in Integrated Water Resource Management offers practical options for water management in the Gavkhouni basin. Environmental flow describes the quantity, timing, and quality of water flow required to sustain freshwater, estuarine ecosystems, the human livelihoods, and well-being. A water resources management model is developed in this study for the purpose of improved water management in the Gavkhouni basin. The model involves six stages. The first stage implements a survey of resources and water use. The Environmental flow is calculated in the second stage with the hydraulic method and the Hydrologic Engineering Center- River Analysis System. The third stage applies the calculated environmental flow to the Integrated Water Resource Management approach by means of the Water Evaluation and Planning model. The fourth stage creates seven possible management scenarios in the Water Evaluation and Planning model to be applied in the period ending in the year 2041. These scenarios are ranked in the fifth stage with a multi-criteria decision-making method. The sixth stage applies the best management scenario in the study region. This study's results indicate that the annual drinking water demand under current conditions would rise from 547.6 to 760.2 Mm3 by 2041. The annual industrial water demand is estimated to increase from 213.7 to 400.5 Mm3, and the agricultural water demand is projected to remain constant at 1789.1 Mm3 per yr. The annual drinking water, environmental, industrial, and agricultural unmet demands are estimated to increase from 68.1, 106.5, 73.4, and 470 to 130.1, 186.1, 141.4, and 480 Mm3, respectively. The considered scenarios are (i) change in water supply priority, (ii) change in the population growth trend, (iii) change in return flow and water loss management utilization, (iv) change in the amount of water transferred to the Gavkhouni basin, (v) change of demand management (consumption per capita reduction), (vi) change of agricultural conditions, and (vii) change of industrial conditions. The change in water supply priority and the change in the volume of water transferred to the Gavkhouni basin scenarios are found to be of the highest priority. The best management alternative is chosen with four types of ranking (i.e., water allocation priorities) in which the ranking (i.e., drinking, Industrial, agricultural, environmental unmet water) and fourth ranking (i.e., environmental, drinking, industrial, agricultural Unmet water) are recommended as the best approach.

Impacts of small-scale irrigation water use on environmental flow of ungauged rivers in Africa

Failure in Environmental flow in quantity, timing, and quality leads to failure to support ecosystems, human livelihoods, and well-being. Irrigation water use is one of the main actors in impacting the water flow of rivers in quantity and time but was not well investigated in many ungauged catchments under smallholder irrigation systems. This study examined the impact of irrigation water use on environmental flow in Arata's small ungauged catchment. The study estimated the flow in sub-catchment using the area ratio method, the crop irrigation water requirement using F.A.O. cropwat 8.0, and the water balance in the Water Evaluation and Planning System tool and the environmental flow in Tennants, Q95, asnd local area thumb rule. The result showed that the minimum environmental flow of the Arata catchment is 290, 310, and 60 li/sec in the Tennant, Q95, and the local thumb rule. Irrigation consumes only 9% of the water resources of the catchment while 91% is contributed to downstream lake Ziway via Ketar river. January and February have unmet water demand and zero environmental flow. In December Tennant's 10% and Q95 recommended environmental flow had 19% and 24% deficit while the thumb rule environmental flow is 291% more than the minimum requirement. The rest of the months are by far more than the minimum environmental flow requirement. Given the result, meeting the environmental flow of the system throughout the year needs the installation of a water storage facility from upstream to downstream, the introduction of different water-saving irrigation technologies, farmers' capacity building in irrigation water management, and a standardized environmental flow estimation mechanism.

Inter-Industry Transfer of Intermediate Virtual Water Scarcity Risk: The Case of China

Multiple factors need to be considered when allocating water resources, among which water scarcity risk is often ignored. However, the unmet water demand of upstream sectors with high water dependency will exacerbate water scarcity, and lead to potential economic risk to the industrial chain. To solve it, we propose a method to quantify the intermediate virtual water scarcity risk transfer via the intermediate use matrix and Leontief inverse matrix, and apply it to virtual water trade in China in 2018. Meaningful conclusions are drawn as follows: (i) Although the water-use efficiency of all sectors in China increased steadily from 2007 to 2018, the overall input concentration of virtual water scarcity risk showed a rising trend, reflecting the gradual increase in the vulnerability of the industrial chain to water shortage. (ii) The virtual water scarcity risk in China mainly transferred through the secondary industry. The secondary industry accounted for 51.8% of the output and 71.8% of the input in the intermediate virtual water transfer, while 77.0% and 74.7%, respectively, in intermediate virtual water scarcity risk output and input. (iii) From 2007 to 2018, agriculture, chemical industry, metallurgy, electricity and heat supply always ranked as the top four of intermediate virtual water scarcity risk output sectors. As their downstream sectors, the construction industry, metallurgy, and other services are stable within the top four input sectors. (iv) The virtual water scarcity risk upstream transmitted is significantly dispersed after the intermediate inputs process, indicating that abundant import relationships are conducive to reduce the risk taken in. From the perspective of intermediate input, this paper argues that it is necessary to both ensure the water supply of the upstream source sectors and disperse the downstream import sources. Moreover, enriching industrial structures and closing production linkages between sectors is also beneficial for promoting sustainable economic development.

Management of water Issues in Taiz basin, Yemen

Generally, the study area including the city of Taiz, in particular is suffering from an acute shortage of water due to the increase of the growing demand on water for domestic and industrial needs as well as the water needs for agriculture in the region. In addition, the water resources in the study area are limited to the aquifers while water extraction rates exceed the natural recharge and the use is not effective. Therefore, it highlights the importance of water demand management to maintain the quantity and quality of drinking water and domestic use, irrigation and industry. The objectives of this study is to evaluate current and future vulnerability of water sources in the study area; Development of scenarios and analysis of future water balance to find out the best solution to the problem of water in Taiz basin as the study area; Select the appropriate scenario to resolve the water problem. The results of this study will assist decision makers in the field of water resources for better planning and management in the future. During the period 15/1/2013 to 15/4/2013 Implementation of the field study in 1501water points, these water points are distributed between 954 hand-dug well, 479 deep well, 50 springs, five water collection tanks, two dams, and six water retaining walls. For calculating the amount of water supply in the region and the amount of water deficit, in addition to knowing the amount of needs that must be secured in the future, Water Evaluation And Planning (WEAP) application as Decision Support System (DSS) to manage the supply and demand for water in Taiz basin as the study area. The analysis and results using WEAP program include the following themes: Ground water storage in the aquifers: The usable storage for the base year of the model (2013) has been calculated for the five sub-basins in the study area, Estimated ground water storage in alluvial aquifer (in Mm3) ranged 221.52-
 415.36 Mm3 at best estimate at 332.29 Mm3, groundwater storage in Volcanic aquifer ranged 129.98-2599.52 Mm3 at best estimate 259.95, whereas groundwater storage in sandstone aquifer ranged 5.044- 50.44Mm3 at best estimate at 10.088; Unmet water demand, The gap between supply and demand for water in the study area was estimated as (47,692,840.9 m3). Preliminary, set of adaptation strategies that address water scarcity; Interpret the proposed set of adaptation strategies to solve water issue from improve water services and water management for the urban area as part of the study in Central and Al Hawban Sub Catchment:
 (Increase the coverage rates for water services, Diversify water sources for the city, Efficient water management, Implementation of control and water quality program in water sources and drinking water factories, Development of specialized human cadres technically and administratively for the development of water management, Flow of water services from different water sources….. etc.); and Improve water projects and water management for the rural area as part of the study area Al Dabab Sub Catchment, Al Janad Sub Catchment and Thi- Sufal Al Haimah Sub Catchment: Commitment of the Commission basin management to Upper Rasyan Valley, The formation of committees Sub-water basin to ensure the management of water resources from the lower level, Resolving water conflicts in different regions of the study area and the basin provider of water to the city of Taiz, Community participation by establishment of water users associations (WUAs) in the sub- basin areas.

A Novel Approach Based on Machine Learning and Public Engagement to Predict Water-Scarcity Risk in Urban Areas

Climate change, population growth and urban sprawl have put a strain on water supplies across the world, making it difficult to meet water demand, especially in city regions where more than half of the world’s population now reside. Due to the complex urban fabric, conventional techniques should be developed to diagnose water shortage risk (WSR) by engaging crowdsourcing. This study aims to develop a novel approach based on public participation (PP) with a geographic information system coupled with machine learning (ML) in the urban water domain. The approach was used to detect (WSR) in two ways, namely, prediction using ML models directly and using the weighted linear combination (WLC) function in GIS. Five types of ML algorithm, namely, support vector machine (SVM), multilayer perceptron, K-nearest neighbour, random forest and naïve Bayes, were incorporated for this purpose. The Shapley additive explanation model was added to analyse the results. The Water Evolution and Planning system was also used to predict unmet water demand as a relevant criterion, which was aggregated with other criteria. The five algorithms that were used in this work indicated that diagnosing WSR using PP achieved good-to-perfect accuracy. In addition, the findings of the prediction process achieved high accuracy in the two proposed techniques. However, the weights of relevant criteria that were extracted by SVM achieved higher accuracy than the weights of the other four models. Furthermore, the average weights of the five models that were applied in the WLC technique increased the prediction accuracy of WSR. Although the uncertainty ratio was associated with the results, the novel approach interpreted the results clearly, supporting decision makers in the proactive exploration processes of urban WSR, to choose the appropriate alternatives at the right time.

Assessment of Agricultural Water Sufficiency under Climate and Land Use Changes in the Lam Takong River Basin

To narrow the gap of agricultural water insufficiency in the Lam Takong River Basin, Thailand, we conducted an assessment of water availability and agricultural water demand under climate and land use changes. The water availability was estimated by SWAT, which was calibrated and validated during 2008–2012 and 2013–2018 against the observed daily discharge at the M.164 station. Measured and simulated discharges showed good agreement during calibration and validation, as indicated by values of 0.75 and 0.69 for R2 and 0.74 and 0.63 for Nash–Sutcliffe Efficiency, respectively. The results of GCMs (IPSL-CM5-MR, NorESM1-M, and CanESM2) under RCPs 4.5 and 8.5 were calculated to investigate changes in rainfall and temperature during 2020–2099. The warming tendencies of future maximum and minimum temperatures were projected as 0.018 and 0.022 °C/year and 0.038 and 0.045 °C/year under RCPs 4.5 and 8.5, respectively. The future rainfall was found to increase by 0.34 and 1.06 mm/year under RCPs 4.5 and 8.5, respectively. As compared to the 2017 baseline, the future planted areas of rice, maize, and cassava were projected to decrease during 2020–2099, while the sugarcane plantation area was expected to increase until 2079 and then decline. The top three greatest increases in future land use area were identified as residential and built-up land (in 2099), water bodies (in 2099), and other agricultural land (in 2059), while the three largest decrease rates were paddy fields (in 2099), forest land (in 2099), and orchards (during 2059–2079). Under the increased reservoir storage and future climate and land use changes, the maximum and minimum increases in annual discharge were 1.4 (RCP 8.5) and 0.1 million m3 (RCP 4.5) during 2060–2079. The sugarcane water demand calculated by CROPWAT was solely projected to increase from baseline to 2099 under RCP 4.5, while the increase for sugarcane and cassava was found for RCP 8.5. The future unmet water demand was found to increase under RCPs 4.5 and 8.5, and the highest deficits would take place in June and March during 2020–2039 and 2040–2099, respectively. In this context, it is remarkable that the obtained results are able to capture the continued and growing imbalance between water supply and agricultural demand exacerbated by future climatic and anthropogenic land use changes. This research contributes new insight for compiling a comprehensive set of actions to effectively build resilience and ensure future water sufficiency in the Lam Takong River Basin.

Integrated water management under climate change through the application of the WEAP model in a Mediterranean arid region

Abstract This research aims at establishing an integrated modelling framework to assess the impact of climate change on water supply and demand across an arid area in the western Haouz plain in Morocco. Five general circulation models (GCMs) are used to evaluate the availability of future water resources under Representative Concentration Pathways (RCP4.5 and RCP8.5 emission scenarios). The projected crop water demand and irrigation water demand were analysed using the Aquacrop software, taking into account the impact of climate change on both reference evapotranspiration and crop cycle lengths. The future water balance is simulated by means of the Water Evaluation And Planning (WEAP) tool, including several socio-economic and land use scenarios under RCP4.5 and RCP8.5 scenarios. The results reveal an important decrease in net precipitation with an average of −36.2% and −50.5% under RCP4.5 and RCP8.5 scenarios, respectively. In terms of water balance, the ‘business as usual’ scenario would lead to an increasing unmet water demand of about +22% in the 2050 horizon and to an increased depletion of the water table that could reach 2 m/year. Changing water management and use practices remains the only solution to ensure sustainable water use and deal with the projected water scarcity.

Analysis of Water Supply-Demand Based on Socioeconomic Efficiency

Water resource is an important factor restricting social-economic development. Hebei Province is one of the regions suffering from severe water shortage in China. Based on the Water Resources Assessment and Planning model, population growth, economic growth, water-saving, and integrated scenarios were established. The water demand and supply in Hebei Province in 2025 and 2035 were forecasted in this study. The research results show that agriculture is the main unmet water demand sector. In the absence of large-scale population inflows, the local population growth has little impact on the changes in water supply-demand. Economic development is one of the main factors affecting water balance. The water-saving scenario has the greatest impact on water supply-demand. Compared to population and economic growth scenarios, the simulation results of water demand and unmet water demand were the smallest. Under an integrated scenario, the current situation of water shortage in Hebei has been greatly improved, but there is still a demand shortage of44.12×108 m3 in 2030. It is necessary to take measures to improve the carrying capacity of water resources in various regions of Hebei Province and narrow the regional gap. This study provided a reference for the rational utilization of water resources.

Analyzing and Evaluating Future Water Demand Using WaterGEMS and Population Forecasting Methods for Narangi Village, Maharashtra, India

The analysis of the water distribution network [WDN] is essential for a sufficient water supply. In the present study, the water distribution network [WDN] of the Narangi village in Virar was analysed using WaterGEMS software. The obtained results from the analysis were used to evaluate the impact of the growing population on the water distribution system in the coming decades, i.e., from 2020 to 2050. For population forecasting, the arithmetical increase and geometrical increase methods were adopted which were later used as “Low Population Growth Scenario" [LGS] and "High Population Growth Scenario" [HGS] respectively. The results obtained show that the maximum flow is observed in pipe 1, and the maximum demand is seen at junction 67. In 2020, the flow rate in Pipe 1 was 1036 litres per minute, but by 2050, it had risen to 1655 litres per minute. Demand at junction 67 was 54 litres per minute in 2020, and it had escalated to 86 litres per minute by 2050. This shows an increasing trend in pipe flow and demand at junctions due to the growing population over the decades. The future water demand is estimated under two population growth scenarios i.e., LGS and HGS. The comparison shows that unmet water demand estimated using the HGS, i.e., 0.223 and 0.601 million m3, is more than the LGS, i.e., 0.035 and 0.174 million m3 for the years 2040 and 2050, respectively. This signifies that unmet water demand in HGS and LGS will result in water scarcity in the study area. As a result, new water sources and the construction of new storage tanks should be planned and implemented as measures to reduce future unmet water demand.

Water Demand and Supply Analysis using WEAP Model for Veda River Basin Madhya Pradesh (Nimar Region), India

Significant gaps exist in water management strategies implemented in the sub-basin of Narmada River, the Veda River Basin. Hence, the main goal of this study is to predict water demand and supply, recharge and draft with the use of the Water Evaluation and Planning System (WEAP) Model. The study area is watershed of the Veda River located in the Nimar region of Madhya Pradesh, and Middle Narmada River sub-basin of India. In this study, the WEAP model is used as a decision support system for watershed management. The WEAP model uses water balance approach for the generation of results, based on that 4 types of scenarios have been developed are high population growth, high industrial growth, rainwater harvesting, and water storage structures for future trends. The unmet water demands were simulated in all administrative blocks, catchments, and industries which amounting to 9.58´108 m3 in 2011 and 9.65´108 m3 in 2030. Results suggested that the addition of water storage structures as well as artificial groundwater recharge structures reduce the unmet water demand for domestic consumption and meet irrigation water requirements.
 HIGHLIGHTS
 
 Watershed management using a Decision Support System
 GIS and WEAP (Water Evaluation and Planning System) model used in order to find demand and supply of water
 Scenarios generated based on demand and supply analysis
 Analysis of scenarios and future suggestions
 
 GRAPHICAL ABSTRACT

Implications of water abstraction on the interconnected Central Rift Valley Lakes sub-basin of Ethiopia using WEAP

Study regionCentral Rift Valley Lakes sub-basin, Ethiopia. Study focusThe competition for water is rapidly increasing in Central Rift Valley lakes sub-basin due to the combined effect of various water resources developments. However, the impacts of recent and future water resources development pathways on the water balance of the three interconnected lakes (i.e. Lake Ziway, Langano and Abiyata) are unknown. The Water Evaluation And Planning (WEAP) model was used to assess the development impacts on water resources of the interconnected lakes. We considered three development pathways that are, recent (2009–2018), short-term (2019–2028) and long-term development (2029–2038). Lake Ziway water inflows from six catchments were estimated using the Hydrologiska Byråns Vattenbalansavdelning (HBV) rainfall-runoff model. Crop water requirements for irrigation schemes were estimated by the CROPWAT model. New hydrological insights for the regionWEAP simulations show a total water demand of 102.3 Mm3 under the recent development pathway that increases by 46% and 118% for short-term and long-term development pathways, respectively. This will notably affect the water balance of the interconnected lakes and cause an unmet water demand of 47.9 Mm3 for the long-term (2028–2038). For Lake Ziway and Abiyata, water levels will decrease substantially to cause water scarcity in the long-term, and developments in Lake Ziway will significantly affect water storage in Lake Abiyata storages in Lake Abiyata. Overall, future developments will threaten the water resource of the interconnected lake system.

Impact of Natural and Anthropogenic Stresses on Surface and Groundwater Supply Sources of the Upper Awash Sub-Basin, Central Ethiopia

Improving water security is critical to delivering the best outcomes for development. In Ethiopia, the upper Awash sub-basin supports expanding urban and industrial areas, with increasing water demands. Studies have preferentially focused either on surface water hydrology or on groundwater characterization. However, novel tools are required to support the conjunctive use of surface and groundwater for competing users under potential climate change impacts. In this paper, we present research based on a WEAP-MODFLOW link configured for four catchments in the upper Awash sub-basin (Akaki, Melka Kunture, Mojo, and Koka). The Akaki catchment supplies water for Addis Ababa city. Unlike most surface water hydrological models, both supply (surface water and groundwater) and demand (domestic, industrial, and livestock) are modeled. The tool was used to evaluate the impacts of population growth, leakage, expansion of surface and groundwater supply schemes, and climate change scenarios up to the year 2030. Considering the high population growth rate scenario for Addis Ababa city, the unmet domestic water demand may increase to 760 MCM in 2030. Water leakage through poor water supply distribution networks contributed about 23% of the unmet water demand. Though not significant compared with population and water loss stresses, climate change also affect the supply demand condition in the basin. Planning for more groundwater abstraction without considering additional surface water reservoir schemes will noticeably impact the groundwater resource, with groundwater levels projected to decline by more than 20 m. Even more groundwater level decline is observed In the Akaki catchment, where Addis Ababa city is located. Conjunctive use of surface and groundwater not only boosts the supply demand situation in the basin but will lift off some of the stresses from the groundwater resources. Even under the likely increase in temperature and low precipitation climate scenarios, the conjunctive use resulted in a significant increase in domestic water demand coverage from 26% for the reference condition to 90% in 2030, with minimum effect on the groundwater resources. To improve water security conditions through sustainable utilization of both surface and groundwater resources, policy responses need to consider surface and groundwater conjunctive use. Minimizing water leakage should also be given the highest priority.

Revival of Traditional Cascade Tanks for Achieving Climate Resilience in Drylands of South India

Traditional tanks in arid regions of India have been working to address water demands of the public for more than 2000 years. However, recent decade is witnessing growing domestic and agricultural water demand coupled with rising encroachment and ignorance toward tanks; consequently, intensifying water shortage issues. While climate change is impacting at alarming rates, local agencies have forgotten these tanks that have aided in sustainable water supply solutions for decades apart from municipal water supply. This research, for the first time, estimates water supply-demand for an arid region in South India (Madurai) and lists out the benefits if tanks were managed and desilted. Exploratory investigations for documenting seasonal domestic and agricultural unmet water demand were conducted followed by their validation through ground-truthing across the study period 2002–2019. Results indicated high unmet domestic water demand, estimating ~73% [maximum 365 thousand cubic meters (TCM)] for summer (March to May) and ~33% (maximum 149 TCM) for winter (January and February), and high unmet agricultural water demand estimating ~90% (maximum 5,424 TCM) during North-East monsoon (October to December), and ~95% (maximum 5,161 TCM) during South-West monsoon (June to September). Erratic rainfall pattern was identified as a major cause for higher fluctuations in water availability inside tanks ranging 0–50%, while lack of ownership resulted in increased siltation load ranging 30–70% of the tank's volume. The study found that the major portion of the unmet water demand can be accounted for through rehabilitation of the tanks, as under the rehabilitated tank irrigation scenario the tank storage could attain 200–400% more water than the estimated agricultural water demand. It was concluded that if the cascade tanks were managed appropriately, they could have positive impacts by reducing floods and providing water for drought seasons.