WEAP Research Articles

Assessing Water Demands and Allocation Strategies Using the Water Evaluation and Planning System—A Case Study of the Ghrib Basin, Algeria

The Ghrib Basin is currently encountering water-related challenges due to population growth and growing competition among water users. Therefore, assessing the current water situation is essential for the anticipation of future needs in the region. This paper assesses water demand and allocation strategies in the Ghrib Basin, Algeria, using the Water Evaluation and Planning (WEAP) system. The simulation is based on five scenarios: “Increase in population and agricultural activity”, “Improving agricultural activity”, “Minimum domestic consumption”, “Enhancing Water Resources”, and “Best practice”, (which is a combination of two scenarios, i.e., “Improving agricultural activity” and ”Minimum domestic consumption”). The simulation outcomes indicate that the “Best practice” scenario represents the most advantageous and beneficial scenario by which the problem of the unmet demand can be solved. The resulting simulations indicated the need for the employment of water-efficient irrigation systems as well as the encouragement of sustainable water use, such as drip irrigation, which necessitates coordinated efforts and particular infrastructural investments. The derived outcomes are highly convincing and have the potential to serve as a decision support system for the effective governance of water resources in the Ghrib Basin. The methodology utilized in this study has the potential to be implemented in any basin across the globe.

Projecting irrigation demand under IPCC climate change scenarios using WEAP modeling in the Rechna Doab, Pakistan

Pakistan is currently facing significant water scarcity issues, intensified by climate change. The main water source, the transboundary Indus River system, faces challenges such as water management, limited data availability, and inadequate management, leading to a gap between water demand and supply across various sectors. Agriculture, which consumes over 95 % of the country’s water resources, contributes nearly 25 % to the GDP, but is heavily dependent on irrigation due to limited rainfall. With rainfall meeting only 15 % of crop water requirements, groundwater plays a critical role, covering 40–60 % of irrigation needs. This study focuses on the Rechna Doab in the Indus Basin Irrigation System (IBIS) using the WEAP (Water Evaluation and Planning) model to assess the supply-demand gap under IPCC's climate change scenarios from Assessment Report Six (AR6). The main findings indicate: (1) Under SSP 8.5, unmet demand in the Upper Chenab Canal and other regions will increase by 33–47 % by mid-century; (2) demand site coverage will decline significantly, especially in Lower Gugera and Jhang branches; (3) groundwater dependency will increase substantially in response to the growing supply-demand gap. This work contributes to improving water management in Rechna Doab by providing a clear framework for adapting water resources to climate change using WEAP projections under various IPCC scenarios.

Assessing water supply/demand dynamic balance in arid environments with policy options: a case study of Kuwait

ABSTRACT The water situation in arid environments is fragile because of climate change, population growth, economic development, irrational behavior in consumption patterns, and water pollution, which in their entirety threaten water security for such environments. The Water Evaluation and Planning (WEAP) (a planning software) was used to assess the actual (2000–2023) water supply sustainability with realistic annual growth rates to project (2024–2035) water demands for Kuwait's water future. The actual total water supply was found to be 1,375 Mm3/yr, of which 44% was for domestic, 5% for industrial, and 51% for agricultural water uses. It was also found that the per capita consumption for domestic and industrial purposes was 214 m3/yr. Suitable growth rates were as follows: 2, 1.5, and 1% for domestic, industrial, and agricultural sectors, respectively. This will result in water shortage of 235 Mm3/yr during the period 2024–2035. Kuwait is called to implement strategic solutions to fully reuse treated wastewater and the virtual water concept for agricultural development purposes. This study demonstrates that when Kuwait implements these solutions, it can reduce CO2 emissions by 1.175 million tons saving $573 million annually. With the proper measures and policies, Kuwait can reduce their bulk water demand by 235 million cubic meters saving $1.15 billion dollars per year.

Effectiveness of wetlands as reservoirs for integrated water resource management in the Ruzizi plain based on water evaluation and planning (WEAP) approach for a climate-resilient future in eastern D.R. Congo

It is widely predicted that climate change’s adverse effects will intensify in the future, and along with inadequate agricultural practices, settlement development, and other anthropic activities, could contribute to rapid wetland degradation and thus exert significant negative effects on local communities. This study sought to develop an approach based on the Integrated Water Resource Management (IWRM) in the Ruzizi Plain, eastern Democratic Republic of Congo (DRC), where adverse effects of the climate change are increasingly recurrent. Initially, we analyzed the trends of climate data for the last three decades (1990–2022). Subsequently, the Water Evaluation and Planning (WEAP) approach was employed on two contrasting watersheds to estimate current and future water demands in the region and how local wetlands could serve as reservoirs to meeting water demands. Results indicate that the Ruzizi Plain is facing escalating water challenges owing to climate change, rapid population growth, and evolving land-use patterns. These factors are expected to affect water quality and quantity, and thus, increase pressure on wetland ecosystems. The analysis of past data shows recurrence of dry years (SPI ≤ − 1.5), reduced daily low-intensity rainfall (Pmm < 10 mm), and a significant increase in extreme rainfall events (Pmm ≥ 25 mm). The WEAP outcomes revealed significant variations in future water availability, demand, and potential stressors across watersheds. Cropland and livestock are the main water consumers in rural wetlands, while households, cropland (at a lesser extent), and other urban uses exert significant water demands on wetlands located in urban environments. Of three test scenarios, the one presenting wetlands as water reservoirs seemed promising than those considered optimal (based on policies regulating water use) and rational (stationary inputs but with a decrease in daily allocation). These findings highlight the impact of climate change in the Ruzizi plain, emphasizing the urgency of implementing adaptive measures. This study advocates for the necessity of the IWRM approach to enhance water resilience, fostering sustainable development and wetland preservation under changing climate.

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.

A WEAP-assisted agent-based modeling approach for watershed planning in a coupled human and nature system

ABSTRACT Coupled human and nature systems exhibit dynamic water demands due to diverse consumer socio-economic characteristics, resulting in inherent complexities. Modeling such systems effectively entails adopting an agent-based methodology. To enhance comprehension of water resource management in the Zarrineh-Roud Basin, northwest of Iran, a comprehensive hydrological-behavioral model has been utilized. This model consists of two primary components: An agent-based model (ABM) for simulating farmers’ decision-making processes and a water evaluation and planning (WEAP) model for simulating catchment area, cultivated area, and agricultural water consumption. Validation outcomes of the simulation model demonstrate precise estimation, particularly in the runoff estimation of the Nezam Abad hydrometric station, with statistically favorable correlation coefficient (R2) and Nash–Sutcliffe index (NS) values of 0.78 and 0.75, respectively. Analysis of different management scenarios indicates that with ample government funds, simultaneous implementation of ‘Education and increasing environmental awareness’ and ‘Alternative employment’ policies can significantly improve water resources conditions and income. In scenarios with limited financial resources, a combined implementation of ‘Water pricing,’ ‘Alternative employment,’ and ‘Education and raising environmental awareness’ emerges as the most effective strategy for managing water resources, albeit with a slight reduction in farmers’ income.

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.

Assessment of Future Water Demand Utilizing the Weap Model in Bhavnagar City, Gujarat, India

Abstract: Water resources management and analysis is very critical in today’s ever increasing and demanding world. Different types of schemes and software for management are available to meet these requirements. WEAP (Water Evaluation and Planning) software is an integrated approach towards evaluating and planning of water demand and supply that can be very helpful in analysing and understanding water requirements of a particular city, area or region based on various inputs and further trying to understand and predict the future requirements. In this study, a WEAP model for future water demand of Bhavnagar city in Gujarat, is developed, that can predict the water demand requirement upto year 2041. Evaluation of WEAP is done based on census data for 2011 (as census data for 2021 for 10 year period was discontinued due to Covid-19 pandemic), considering 1.67% of growth rate. The final results include three scenarios, namely, Low population growth rate 1.5%, Moderated population growth rate 2%, High population growth rate 2.5%.

Future perspective of water budget in the event of three scenarios in Afghanistan using the WEAP program

In this study, WEAP (Water Evaluation and Planning System) software was used for the water resources management and water budget calculation of the Balkh River Basin, the sub-basin of the Northern River Basin in Afghanistan. The water resources in the basin and 10 demand sites (irrigation, drinking water, etc.) were introduced to the software, and precipitation, evaporation, runoff, etc., were obtained from stream gauging stations for long years (2010–2021). Hydrological data and information on population, irrigation lands, and drinking water use were entered. Scenario-1 (current situation) was created by entering the existing data in the created model. Subsequently, the long-term monthly average maximum and minimum values of precipitation, evaporation, runoff, and similar values were added to the current scenario. Forecast results between the years (2022–2050) were created with Scenario-2 (optimistic case) and Scenario-3 (pessimistic case), and analyzes were carried out in three different situations, and the results were examined. According to the analyzes, the current water potential found by the inclusion of surface water and groundwater from the Mezar-i-Sharif Region in the Balkh River Basin is 4747 million m3 annually; it has been determined that this value will be approximately 9741 million m3 in 2050 in the optimistic scenario and 1811 million m3 in the pessimistic scenario. It has been determined that the water need, which cannot be met as 29,394 million m3 in the current situation, approximately 14103 m3 in the optimistic scenario, and 49,979 million m3 in the pessimistic scenario in 2050. While the current met need of the Balkh River Basin is 7.81 % with losses, it has been calculated as 27.14 % in an optimistic situation and 1.71 % in a pessimistic situation for 2050. While the current met needs of the Basin, excluding losses, is 12 %, it is calculated as 33.9 % in the optimistic situation and 3.1 % in the pessimistic situation for 2050. It is understood that Afghanistan's water resources should be handled with an integrated water resources management (IWRM) approach, and future water resource planning should be made by considering human needs, environmental impact, and government visions. Water resources should be planned most efficiently by controlling the amount of undocumented wells, drilling, and detecting the losses and leakages in the existing systems with certain methods.

Strategic Decision-Making in Sustainable Water Management Using Demand Analysis and the Water Evaluation and Planning Model

Water infrastructure management relies on information, communication strategies, and affordable technologies. This paper used demand analysis and modeling to guide strategic decision-making in sustainable water management for the urban cluster in Tlemcen, Algeria. To achieve this, the water supply and demand of the study area were assessed over the past three decades. The Water Evaluation and Planning (WEAP) system was employed considering different future scenarios to help decision-makers consider the best choices for sustainable urban water resources management. The results showed that the average water production and distribution efficiency was only 46% due to the high network loss. Therefore, urgent action should be considered to increase the efficiency of the distribution network. Moreover, the outcome showed severe unmet demand in 2050, which can be managed by improving the water networks, increasing conventional water production, and reducing personal water consumption. In cooperation with key stakeholders, new scenarios can be analyzed to develop efficient water management policies and to implement sustainable water allocation approaches.

Flow alterations due a constructed reservoir in the Menik Ganga basin, Sri Lanka

Natural water flows and their ecosystems are altered due to manmade hydraulic structures like dams. However, limited research on hydrologic alteration has been carried out in developing countries. This research explores the hydrologic alterations which occurred in the Menik Ganga basin, Sri Lanka due to the Weheragala reservoir constructed in 2009 for inter basin transfer. The hydrologic variations of the flow regime due to the construction of the reservoir was analyzed using Indicators of Hydrologic Alterations (IHA). For this purpose, we compared the calculated IHAs for streamflow at the Kataragama station (located downstream of Weheragala) during pre-construction (1990–2009) and post construction (2010–2019) periods. Also, the IHAs of simulated flows from the Water Evaluation And Planning (WEAP) model during 2010–2019 was compared with observed gauge discharge during the same period. The monthly observed flows in the “Maha” rainfall season (September to March) demonstrated a decreasing trend in post dam period with respect to pre dam period (highest decrease of 77 m3/s during October), whilst it showed an increasing trend (highest increase of 5 m3/s during August) in the Yala season (May to August) in the post-reservoir construction scenario. This was further visualized by comparing the indicators of the simulated flows with observed for post reservoir period, in which highest percentage differences occurred in June (− 4000% in 2016) and November (− 300% in 2010) for Yala and Maha periods respectively. Large alterations of the river flow due to the impoundment depicted by higher percentage differences. These alterations are extensively examined by other indicators as well. The fluctuations of flows have been decreased due to the construction of the reservoir which resulted in reductions of low and high pulses. The results are highly appealing to the authorities who are in water resources management to reach sustainable goals.

Partitioning blue and green water sources of evapotranspiration using the water evaluation and planning (WEAP) model

Abstract Understanding agricultural water use by sources such as rainwater (green water) or irrigation water (blue water) is vital to manage scarce freshwater resources. Tracing sources of evapotranspiration increases water management efficiency. This study proposes a two-bucket soil moisture water balance approach to trace sources of evapotranspiration over irrigated landscapes in the Awash Basin, Ethiopia, which is modeled in the water evaluation and planning model. Algorithms are devised to separate actual evapotranspiration into blue and green sources. The results showed annual basin renewable water of 15.78 BCM in the form of streamflow (4.65 BCM), stored water (3.54 BCM), and groundwater percolation (7.59 BCM). Annual actual evapotranspiration over irrigated landscapes was 805 MCM, which was separated as blue evapotranspiration (88.4%) and green evapotranspiration (11.6%). The findings also demonstrate that blue evapotranspiration predominantly occurs during dry months, indicating heavy reliance on stored water for irrigated landscapes. Subbasin-level analyses showed varying blue/green evapotranspiration patterns based on precipitation and irrigated agriculture. Irrigation accounted for less than 3% of the streamflow in upstream basins, while midstream and downstream basins utilized up to 30 and 70%, respectively. The complementary use of rainfall and irrigation in most parts of the basin is considered to be of interest to water managers.

Assessment of long-term water demand for the Mgeni system using Water Evaluation and Planning (WEAP) model considering demographics and extended dry climate periods

The Mgeni System is recognised as the main source of water supply for the Durban and Pietermaritzburg region in South Africa. This area is regarded as the primary economic hub of KwaZulu-Natal Province, and this brings about a high level of demographic pressure, with potential water supply problems in the future. This study investigates the water resource situation in the Mgeni System and evaluates future supply and demand accounting based on the (Water Evaluation and Planning) WEAP software. WEAP was used to analyse the study area for the period 2009–2050 to assess the impacts of various scenarios on future water supply shortfalls. Four scenarios were used, which take into account changing population growth rates and extended dry climates. The study found that the catchment is relatively sensitive to changes in population growth and extended dry climates, and this will alter the water availability significantly, causing a water supply deficit. In response to the projected future water demands, one technique to overcome the unmet demand is by introducing water conservation and demand management (WC/DM) strategies to reduce the water losses and shortfall encountered. By implementing adequate measures, water losses can be reduced, preventing water scarcity and giving decision makers time to provide further solutions to water supply problems.

Socio-Hydrological Approach for Water Resource Management and Human Well-Being in Pinglin District, Taiwan

Despite being a limited resource, pollution, poor management, and other drivers like climate change make available water unsuitable and insufficient for human consumption and ecosystem maintenance. Therefore, a transdisciplinary approach is needed for managing this precious resource. The overall aim of this paper is to address water inequalities and improve human well-being using an integrated approach of key informant interviews, hydrological modeling, and the payment of ecosystem services (PES) scheme in Pinglin District, Taiwan. This site is an upstream area of Feicui Reservoir, which protects the downstream tap water supply. Key informant interviews were conducted to identify the gaps in and challenges to water resource management. This was followed by a scenario-based hydrological simulation using a Water Evaluation and Planning (WEAP) tool to project future water quality by the year 2050 (using biochemical oxygen demand and total coliform content as key indicator parameters) and to trace the factors responsible for water pollution. Survey analysis of key informant interviews depicts that this area is facing several challenges, such as lack of water infrastructure, agricultural subsidy, construction restrictions, etc., which cumulatively cause water scarcity in the upstream regions. On the other hand, hydrological simulation results show that population decline and climate change under an RCP 8.5 scenario will have an enormous negative impact on water quality. The concentrations of BOD and E. coli in river water will expand by 110.1% and 117.3%, respectively, by 2050 compared to 2018. Finally, the results of the study suggest that the PES scheme can play a positive role in enabling integrated water resource management. For example construction of a small-scale wastewater treatment plant in the upstream area will reduce the total E. coli concentration by up to 90%. While the initial cost of construction will be taken care of by the government, the operation and management cost of this infrastructure will be covered by people living downstream, who need to pay only $0.10 per year per person. The obtained results should be vital for both the stakeholders and decision-makers in this region.

Water Balance Assessment, Land Use Land Cover Change and Increasing Water Demand in Three Major Watersheds in Jember, East Java, Indonesia

Jember Regency is the third largest agricultural area in East Java Province. Expansion of built-up and agricultural areas occurred and significantly changed the landscape. Moreover, increasing both types of land cover will increase water consumption. Therefore, there may be changes in the condition of the water balance in the Jember Regency area. This area has three major watersheds: Bedadung, Mayang, and Tanggul. This study evaluated the water balance condition at the three major watersheds in Jember, East Java, Indonesia. The WEAP (Water Evaluation and Planning) model calculated the water balance. Research procedures include (1) inventory of spatial and non-spatial data; (2) setup of the WEAP scheme; (3) Calibration; (4) Validation; and (5) Simulation of water balance model in scenario increasing water demand and land-use change). From 1997 to 2020, the water balance was evaluated using a 10-day interval. The results show that from the November 1st to August 2nd periods, the watershed can supply all demand sites with 100% coverage. However, from August 2nd t to October 3rd periods, the watershed’s ability to supply the water needs decreased. This deficit is due mainly to the uneven rainfall distribution between rainy and dry seasons. Variation in annual rainfall received from 1997 to 2020 also affects the water balance’s surplus and deficit. The fluctuation of land-use change contributed to the surplus and shortage of water balance.&#x0D; &#x0D; Keywords : Supply; Demand; Water Balance; WEAP; Jember; East Java&#x0D; Copyright (c) 2023 Geosfera Indonesia and Department of Geography Education, University of Jember&#x0D; This work is licensed under a Creative Commons Attribution-Share A like 4.0 International License

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.

Application of Weap Model for Managing Water Resources in Iraq: A Review

Due to the construction of dams in upstream countries and the usage of surface irrigation systems, Iraq has been experiencing a water shortage. Due to population increase and the expansion of the industrial and agricultural sectors, the country is having difficulty keeping up with the rising demand for water. Many previous studies carried out to optimize the water resources management in Iraq over the two decades using Water Evaluation and Planning (WEAP) modeling considering various aspects and different water resources throughout Iraq provinces. This study aims to find out if the WEAP modeling is reliable to optimize water resources management, fourteen previous studies were reviewed to figure out the fields they focused on, the study limitations, and the obtained results. It was found that the WEAP model is reliable for assessing, planning, and optimization of water resources management.

Mitigating Water Shortage via Hydrological Modeling in Old and New Cultivated Lands West of the Nile in Egypt

Middle East and North Africa (MENA) regions are increasingly concerned about water scarcity. Egypt, one of the arid MENA nations that relies primarily on Nile water, faces a water scarcity issue because of a mismatch between demand and supply. This study presents an integrated executive system for managing water resources in two regions of Egypt that have traits with many MENA regions facing water scarcities. Hydrological modeling is required for the modeling of water resources, and model calibration procedures should be implemented to compare the simulated values to the observed and measured values to minimize model errors. The Water Evaluation and Planning (WEAP) model was used in this study to simulate the network systems of Egypt’s Minia Governorate on the western bank of the Nile’s narrow valley and Nubariya in the West Nile Delta, the lower reaches of the Nile. Using field data and experience, as well as other inputs, geographic information system (GIS) software digitized streams using satellite-interpreted data. The models were run, calibrated, and validated. The main calibration objective was to reduce the discrepancy between the actual and modeled flows as much as possible. Nash–Sutcliffe efficiency (NSE), percentage BIAS (PBIAS), volumetric efficiency (VE), and agreement index (d) values were calculated for three calibration cases. For anticipating water shortages until 2050, two scenarios were examined: (1) climate change scenarios based on historical climatic data from 1960 to 1990 and from 1991 to 2020, which led to a prediction scenario (2021–2050) of increasing temperature in the areas leading to evapotranspiration (ET) increases of 5.42% and 5.13% and (2) canal lining scenarios, which found a flow saving in the areas, showing that we can overcome the anticipated water shortage progress if canal lengths are rehabilitated by 10% and 25% in Minia and Nubariya.

Assessment of the Streamflow and Evapotranspiration at Wabiga Juba Basin Using a Water Evaluation and Planning (WEAP) Model

Rapid population growth, industrialization, and agricultural activities have impacted water resources in the arid and semi-arid areas of Somalia. The Lower Juba region in Somalia has been the most affected region. Therefore, an analysis of the hydrological patterns is essential. This paper assesses streamflow and evapotranspiration in the Wabiga Juba basin in Somalia using a hydrological simulation model, namely, the water evaluation and planning (WEAP) system via the soil moisture method. The datasets included 53 (average precipitation) and 13 (streamflow) year periods from two meteorological stations. The estimated values for potential evapotranspiration (11,921.98 to 20,775.39 MCM) were higher than the actual evapotranspiration (4904.10 to 8242.72 MCM) by 50 to 79.5%, respectively. The annual streamflow in Juba Dolow and runoff proportion of the Wabiga Juba River was estimated to be 10% of the annual precipitation. Most of the surface runoff occurred in April (47%), May (31%), October (5%), and November (14%). The streamflow variation responded to the pattern of precipitation. The model performance achieved a Nash–Sutcliffe model efficiency (NSE) coefficient of 0.71, coefficient of determination (R2) of 0.91, and percent bias (PBIAS) of 14%. The WEAP model of the Wabiga Juba basin is a baseline study for water resource management in Somalia to mitigate water shortage impacts due to limited water resources.