The Jordan Valley is a heavily modified, data-limited transboundary river basin where water availability is constrained by both climate conditions and intensive human intervention. This study applies an integrated hydrological and hydrogeochemical modeling framework using the Soil and Water Assessment Tool (SWAT) to quantify basin-scale water availability and quality and to assess climate change impacts for the period 2000–2021. Results indicate that the basin is strongly evapotranspiration-dominated, with mean annual precipitation of 298.9 mm and precipitation-derived evapotranspiration accounting for 66.3% of rainfall. When externally supplied irrigation water is included, total evapotranspiration increases markedly, highlighting the strong dependence of agriculture on imported surface water and groundwater abstractions. Only a small fraction of total water input contributes to river discharge toward the Dead Sea, indicating a very limited internal water surplus. Hydrological dynamics are largely controlled by upstream dams and transboundary diversions, while nitrate and sediment simulations demonstrate a close coupling between hydrology, land use, and water quality. Climate projections suggest further reductions in water availability during the 21st century, exacerbating existing water scarcity. Overall, the study illustrates how intensive regulation and irrigation dependency constrain water availability in the Jordan Valley and in similar heavily modified transboundary river basins.

Public concerns over the groundwater quality of the Gaza Coastal Aquifer has grown significantly in recent years and has focused increasingly on anthropogenic sources for the problem. The Gaza Coastal Aquifer is an important source of water to over 1.3 million residents and is utilized extensively to satisfy agricultural, domestic, and industrial water demands. Evidence indicates that the nitrate (NO₃) levels routinely exceeded the maximum contaminant level (MCL) of 10 mg/L NO₃-N in 90 percent of the water supply wells. Degradation of groundwater quality in the Gaza Coastal Aquifer due to nitrate pollution and the continuously increasing demand for potable water have motivated the restoration of the aquifer. Restoration efforts have intensified the dire need for developing protection alternatives and management options (MOs) such that the ultimate nitrate concentrations at the critical receptors are below the MCL. This paper presents a generic conceptual framework for the management of groundwater contamination from nitrate for the Gaza Coastal Aquifer. The framework incorporates an assessment of existing data and future monitoring needs, conceptual models of groundwater flow and nitrate fate and transport, and decision-making tools to study the impact of different MOs considering both environmental and economic aspects.

Arid and semi-arid regions are generally characterized by water scarcity and low per capita water allocation. This situation is further exacerbated when such areas are agriculturally dominated and encounter a high population growth rate. Faria watershed, Palestine, is one of these semi-arid regions where lack of proper management of natural resources, accompanied with the recent prolonged drought periods in the watershed have negatively affected the existing obtainable surface water and groundwater resources. This situation has compelled the motivation for developing optimal water allocation policies that consider the available water resources under the climatic changes in the watershed such that the socio-economic revenue is maximized. This paper conceptually demonstrates a decision-support-system to integrate different work plans and components in order to assess the conjunctive use of the different water resources in the watershed under different management scenarios driven by climatic changes and land use planning. The framework incorporates an assessment of the existing data and future needs, a GIS framework to facilitate processing and visualization, mathematical models of surface water and groundwater a planning model to evaluate the economic ramifications for different management options, and a multi-criteria decision analysis module.

Aquifers are vulnerable to contamination from residential, agricultural, and industrial pollutants. Agriculture-related activities are well-known to cause nonpoint source pollution of groundwater from nitrate (NO₃). Assessment of groundwater vulnerability to nitrate contamination from nonpoint sources is essential to decision makers, land use planners, environmental regulators, and stakeholders to highlight areas where protection alternative measures should be introduced and where groundwater monitoring and modeling efforts ought to be carried out. Spatial analysis techniques are needed in managing and processing hydrologic and hydrogeologic data. Thus, geographic Information System (GIS) is a sound approach to evaluate the spatial outcomes of the assessment of groundwater vulnerability to nitrate contamination This paper aims at developing a simple yet efficient GIS-based framework to assess groundwater vulnerability to nitrate contamination through the utilization of the well-known DRASTIC model. Since DRASTIC provides an assessment of the intrinsic vulnerability independently from the contaminant of concern, this paper proposes an improvement to the DRASTIC model to account for the vulnerability to nitrate contamination. The Gaza Coastal Aquifer (GCA) was taken as a demonstration example to show method development and applicability.

Flooding is an actual hazard at several watersheds in Tulkarm governorate of Palestine. The lack of integrated planning and appropriate preparedness lead to increased hazard of flood events. This study aims to develop a flood hazard map, using a group of parameters: slope, elevation, drainage density, precipitation, soil texture, land use/land cover, flow accumulation and population density. Analytic Hierarchy Process method and Geographic Information System program were used to weighted parameters. The result showed a flood hazard map with a 12.5 m resolution for Tulkarm study area categorized into five classes (percentage): very low (2%), low (26%), medium (37%), high (28%) and very high (7%) flood hazards. Results were compared with previous studies from the literature, and verified using ground truthing to examine the certainty of the results in three different locations. A group of interventions (structural and non-structural) were proposed for each flood hazard class so that competent authorities could better manage flood hazards. Some of these interventions for high flood vulnerable areas are, applying heavily-engineered structural measures and regular maintenance of rainwater culverts and valley streams. Mapping the flood hazard is an integral part during phases of flood hazard management from mitigation, preparedness, response and recovery.