Water supply sustainability and adaptation strategies under anthropogenic and climatic changes of a meso-scale Mediterranean catchment

Assessing the climate change adaptability of sustainable land management practices regarding water availability and quality: A case study in the Sorraia catchment, Portugal

In Mediterranean catchments, such as the Sorraia catchment in Portugal, it is expected that climate change will increase drought stress and the deterioration of water quality in reservoirs. Sustainable land management (SLM) practices are seen as an adaption measure for those problems, but the effectiveness on improving climate change impacted water availability and quality on catchment scale is still poorly understood. Therefore, this study aims to evaluate the effectiveness of SLM practices in adapting the impacts of climate change on water availability and quality of the Montargil and Maranhão reservoirs in the Sorraia catchment. A well-calibrated Soil Water Assessment Tool model is used to simulate four scenarios (2041-2071 and 2071-2100; representative climate pathways 4.5 and 8.5), to investigate the effects of climate change on total phosphorus load (TP) in streams, reservoir volume, irrigation use and water exploitation index (WEI). Results showed that WEI will not exceed any water stress level while reservoir water quality will worsen. In particular since the TP load in streams flowing into the reservoirs increases and the volume decreases, it is likely that the existing P limitation for eutrophication will be counteracted. Nevertheless, tested SLM practices were able to decrease the TP load in those streams and increase the reservoir volume under future climates. Overall, this study shows that the SLM practices are effective in adapting to the climate change effects regarding reservoir water quality, without worsening the water availability; thus, it is a promising tool that should be investigated further for application by e.g. local land-users and decision makers.

Groundwater contamination in the Gulf Cooperation Council (GCC) countries: a review

Groundwater quality levels are currently deteriorating in Gulf Cooperation Council (GCC) countries due to excessive surface and subsurface human activities. Agricultural and industrial activities, landfill seepage and seawater intrusion have been attributed to the deterioration of groundwater quality in GCC states. Such a deterioration of groundwater quality could affect water security in the region, including human health and the ecosystem. Therefore, this review aims to identify the key causes of groundwater contamination across the GCC countries from the published literature. In addition, the review summarizes the major components of the groundwater contaminants across the GCC countries. The results have shown that heavy metals, several cations and anions are the leading cause of groundwater pollution. In most cases, the level of metals and ion contaminants exceeds both the local and international water quality standards. The results have observed the presence of high levels of coliform and radioactive elements in groundwater, especially Uranium and Radium, thereby posing additional risk to human health through consumption. Considering the scarcity of freshwater resources in GCC, urgent actions are required from the decision-makers and relevant regulatory bodies to set up and implement long-term mitigation strategies and stringent policies that will protect the groundwater resources from the adverse effects of anthropogenic activities.

Malta’s Water Scarcity Challenges: Past, Present, and Future Mitigation Strategies for Sustainable Water Supplies

The small Mediterranean country of Malta, an island located between Italy and North Africa, has been facing and will continue to face water stress and scarcity in the coming years, receiving the designation as the most water stressed country in Europe. In the past, Malta’s water challenges were centered around water quantity concerns, but in more recent years, the severity of their water stress has been strengthened by the deterioration of the groundwater quality and quantity. Through the over-extraction of their groundwater, saltwater intrusion has steadily occurred into their freshwater aquifer systems, worsening their groundwater quality for both domestic and agricultural purposes. The objective of this paper is to conduct an extensive review on the history of Malta’s water problems and how Malta is working to combat its water scarcity concerns. Additionally, this paper investigates the impact of Malta’s water scarcity on its food and energy security challenges. Our study concludes that while Malta has obstacles to overcome in their pursuit of water security and sustainable development, the future remains hopeful, with several alternatives still available. Some of the alternatives explored in this review include wastewater reuse, increased awareness, use of alternative energy sources, rainwater harvesting, and implementation of nation-wide strategic water policies.

Wastewater Reclamation in Major Jordanian Industries: A Viable Component of a Circular Economy

Water scarcity remains the major looming challenge that is facing Jordan. Wastewater reclamation is considered as an alternative source of fresh water in semi-arid areas with water shortage or increased consumption. In the present study, the current status of wastewater reclamation and reuse in Jordan was analyzed considering 30 wastewater treatment plants (WWTPs). The assessment was based on the WWWTPs’ treatment processes in Jordan, the flowrates scale, and the effluents’ average total dissolved solid (TDS) contents. Accordingly, 60% of the WWTPs in Jordan used activated sludge as a treatment technology; 30 WWTPs were small scale (<1 × 104 m3/day); and a total of 17.932 million m3 treated wastewater had low TDS (<1000 ppm) that generally can be used in industries with relatively minimal cost of treatment. Moreover, the analysis classified the 26 million m3 groundwater abstraction by major industries in Jordanian governorates. The results showed that the reclaimed wastewater can fully offset the industrial demand of fresh water in Amman, Zarqa, and Aqaba governorates. Hence, the environmental assessment showed positive impacts of reclaimed wastewater reuse scenario in terms of water depletion (saving of 72.55 million m3 groundwater per year) and climate change (17.683 million kg CO2Eq reduction). The energy recovery assessment in the small- and medium-scale WWTPs (<10 × 104 m3/day) revealed that generation of electricity by anaerobic sludge digestion equates potentially to an offset of 0.11–0.53 kWh/m3. Finally, several barriers and prospects were put forth to help the stakeholders when considering entering into an agreement to supply and/or reuse reclaimed water.

Adaptations in irrigated agriculture in the Mediterranean region: an overview and spatial analysis of implemented strategies

In order to meet future food demand while sustainably managing available land and water resources, irrigated agriculture in semi-arid regions needs to adapt as a response to climate and socio-economic change. In this study, we focus on the Mediterranean region, a dynamic region, which is highly dependent on irrigated agriculture. We provide insight on adaptation strategies implemented on farm level, by doing a systematic review of studies in the region. Our analysis reports 286 implemented adaptations, on 124 different locations throughout the Mediterranean. Additionally, 142 drivers and 324 effects of adaptations were noted. We identified 31 adaptation strategies in 5 main categories: (1) water management, (2) sustainable resource management, (3) technological developments, (4) farm production practices, and (5) farm management. Strategies in the categories water management and farm production practices are most often implemented by farmers in the region. The main driver in the area is water scarcity and adaptations often affected water use and resources in addition to farm practices. Subsequently, we studied the spatial context of adaptations by analyzing the location factors of the five main strategies, using Geographic Information Systems and maximum entropy modeling. Our results show that farmers are more likely to adapt in less rural areas with lower poverty values and better market access, and in areas with higher temperatures and less rainfall. This demonstrates that both biophysical and socio-economic factors determine the context in which adaptations are implemented and that considerable spatial variability in the area exists.

A systematic approach for watershed ecological restoration strategy making: An application in the Taizi River Basin in northern China

Aiming to protect freshwater ecosystems, river ecological restoration has been brought into the research spotlight. However, it is challenging for decision makers to set appropriate objectives and select a combination of rehabilitation acts from numerous possible solutions to meet ecological, economic, and social demands. In this study, we developed a systematic approach to help make an optimal strategy for watershed restoration, which incorporated ecological security assessment and multi-objectives optimization (MOO) into the planning process to enhance restoration efficiency and effectiveness. The river ecological security status was evaluated by using a pressure-state-function-response (PSFR) assessment framework, and MOO was achieved by searching for the Pareto optimal solutions via Non-dominated Sorting Genetic Algorithm II (NSGA-II) to balance tradeoffs between different objectives. Further, we clustered the searched solutions into three types in terms of different optimized objective function values in order to provide insightful information for decision makers. The proposed method was applied in an example rehabilitation project in the Taizi River Basin in northern China. The MOO result in the Taizi River presented a set of Pareto optimal solutions that were classified into three types: I - high ecological improvement, high cost and high benefits solution; II - medial ecological improvement, medial cost and medial economic benefits solution; III - low ecological improvement, low cost and low economic benefits solution. The proposed systematic approach in our study can enhance the effectiveness of riverine ecological restoration project and could provide valuable reference for other ecological restoration planning.

Freshwater vulnerability under high end climate change. A pan-European assessment

As freshwater availability is crucial for securing a sustainable, lower‑carbon future, there is a critical connection between water management and climate policies. Under a rapidly changing climate, it is more important than ever to estimate the degree of future water security. This is a challenging task as it depends on many different variables: the degree of warming and its consequent effects on hydrological resources, the water demand by different sectors, and the possible ameliorations or deteriorations of the effects due to climate change adaptation and mitigation strategies. A simple and transparent conceptual framework has been developed to assess the European vulnerability to freshwater stress under the present hydro-climatic and socioeconomic conditions, in comparison to projections of future vulnerability for different degrees of global warming (1.5°C, 2°C and 4°C), under the high-rate warming scenario (RCP8.5). Different levels of adaptation to climate change are considered in the framework, by employing various relevant pathways of socioeconomic development. A spatially detailed pan-European map of vulnerability to freshwater shortage has been developed at the local administrative level, making this approach extremely useful for supporting regional level policymaking and implementation and strategic planning against future freshwater stress.

Water resources vulnerability assessment in the Adriatic Sea region: the case of Corfu Island

Cross-border water resources management and protection is a complicated task to achieve, lacking a common methodological framework. Especially in the Adriatic region, water used for drinking water supply purposes pass from many different countries, turning its management into a hard task to achieve. During the DRINKADRIA project, a common methodological framework has been developed, for efficient and effective cross-border water supply and resources management, taking into consideration different resources types (surface and groundwater) emphasizing in drinking water supply intake. The common methodology for water resources management is based on four pillars: climate characteristics and climate change, water resources availability, quality, and security. The present paper assesses both present and future vulnerability of water resources in the Adriatic region, with special focus on Corfu Island, Greece. The results showed that climate change is expected to impact negatively on water resources availability while at the same time, water demand is expected to increase. Water quality problems will be intensified especially due to land use changes and salt water intrusion. The analysis identified areas where water resources are more vulnerable, allowing decision makers develop management strategies.

Future water availability in the largest freshwater Mediterranean lake is at great risk as evidenced from simulations with the SWAT model

Inter- and intra-annual water level fluctuations and changes in water flow regime are intrinsic characteristics of Mediterranean lakes. Additionally, considering climate change projections for the water-limited Mediterranean region, increased air temperatures and decreased precipitation are anticipated, leading to dramatic declines in lake water levels as well as severe water scarcity problems. The study site, Lake Beyşehir, the largest freshwater lake in the Mediterranean basin, is - like other Mediterranean lakes - threatened by climatic changes and over-abstraction of water for irrigated crop farming. Therefore, implementation of strict water level management policies is required. In this study, an integrated modeling approach was used to predict the future water levels of Lake Beyşehir in response to potential future changes in climate and land use. Water level estimation was performed by linking the catchment model Soil and Water Assessment Tool (SWAT) with a Support Vector Regression model (ε-SVR). The projected increase in temperature and decrease in precipitation based on the climate change models led to an enhanced potential evapotranspiration and reduced total runoff. On the other hand, the effects of various land use scenarios within the catchment appeared to be comparatively insignificant. According to the ε-SVR model results, changes in hydrological processes caused a water level reduction for all scenarios. Moreover, the MPI-ESM-MR General Circulation Model outputs produced the most dramatic results by predicting that Lake Beyşehir may dry out by the 2040s with the current outflow regime. The results indicate that shallow Mediterranean lakes may face a severe risk of drying out and losing their ecosystem values in the near future if the current intensity of water abstraction is not reduced. In addition, the results also demonstrate that outflow management and sustainable use of water sources are vital to sustain lake ecosystems in water-limited regions.

Modeling the water-satisfied degree for production of the main food crops in China

Water resources are one of the important factors that influence regional crop production and the food security of humans. Most traditional models of crop water demand analysis are built on the basis of a certain crop or macroscopic analysis, which neglect regional crop allocation and the difference of water demand in different crop growing periods. In this paper, a new assessing model, the satisfied degree of crop water requirement, is developed to assess the impacts of water resources on production of six main food crops in China. The six main food crops are spring wheat, winter wheat, corn, early season rice, middle-season rice and late rice. The results show that: (1) there are serious risks of water shortage in China, even in south China with its abundant precipitation; (2) the satisfied degree of crop water demand represents great temporal-spatial changes. On spatial distribution the risks are high in major bases of food production due to influences of cropping system and crop-combinations. Northwest China is a special interesting case. In seasonal fluctuation water shortage is severe in March and September. These risks seriously restrict food production in China. The results also show that the strategic measures of water resources management must be chosen carefully to deal with food security and regional sustainable development in China.