Numerical Prediction of the Efficacy of Treated Wastewater Recharge to Impede Seawater Intrusion in the Coastal Aquifer of Gaza – Palestine

Water Resources Planning and Managemen

Genetic Algorithm Model to Optimize Water Resources Allocation in Gaza Strip

Groundwater aquifer is considered the main and only water supply source for all kind of human usage in Gaza Strip (domestic, agricultural and industrial). This source is severely deteriorated in both quality and quantity for many reasons, includ- ing low rainfall, dramatic increase in the urban areas and population, pollution from overland activities, and seawater intrusion. In 2011, the Palestinian Water Authority has instituted a plan for integrated management of Gaza water resources that considers introducing of new external water resources to the system such as seawater desalination and treatment and reuse of wastewater. In this work, a genatic algorithm model was developed to seek the optimal combination of the management scenarioios of Pales- tinian water authority plan. The optimization code is designed and run using MATLAB R2011b. The objective function maxim- ized the benefits and minimizes the cost related to the use of different sources of water. The decision variables represents water allocation over different users sectors. The benefits from utilizing water for municipal and industrial purposes are based on the marginal value of water which is derived from the economic equilibrium point between supply and demand curves. The benefits from irrigation water are affected by the relationship between crop yield and salinity. The constraints in the optimiza- tion model are allowed to iterate between two bounds (upper bound and lower bound) until the optimal value for each variable is found. The results show that there is a significant improvement in aquifer’s water levels in the majority area of the Gaza Strip for the planning years 2015, 2025, and 2035 providing that the planned phased desalination and wastewater treatment schemes are implemented in the specifies time horizon. The results show that the resulted quality of available water for agriculture use in term of total weighted average of electrical conductivity is 962 µS/cm in the year 2015, and 876 µS/cm in the year 2025, and 842 µS/cm in the planning year 2035. The results also show that the resulted quality of available water for municipal and industrial use in term of total weighted average of electrical conductivity is 867 µS/cm in the year 2015, and 685 µS/cm in the year 2025, and 631 µS/cm in the planning year 2035

A surrogate model for simulation–optimization of aquifer systems subjected to seawater intrusion

This study presents the application of Evolutionary Polynomial Regression (EPR) as a pattern recognition system to predicate the behavior of nonlinear and computationally complex aquifer systems subjected to seawater intrusion (SWI). The developed EPR models are integrated with a multi objective genetic algorithm to examine the efficiency of different arrangements of hydraulic barriers in controlling SWI. The objective of the optimization is to minimize the economic and environmental costs. The developed EPR model is trained and tested for different control scenarios, on sets of data including different pumping patterns as inputs and the corresponding set of numerically calculated outputs. The results are compared with those obtained by direct linking of the numerical simulation model with the optimization tool. The results of the two above-mentioned simulation–optimization (S/O) strategies are in excellent agreement. Three management scenarios are considered involving simultaneous use of abstraction and recharge to control SWI. Minimization of cost of the management process and the salinity levels in the aquifer are the two objective functions used for evaluating the efficiency of each management scenario. By considering the effects of the unsaturated zone, a subsurface pond is used to collect the water and artificially recharge the aquifer. The distinguished feature of EPR emerges in its application as the metamodel in the S/O process where it significantly reduces the overall computational complexity and time. The results also suggest that the application of other sources of water such as treated waste water (TWW) and/or storm water, coupled with continuous abstraction of brackish water and its desalination and use is the most cost effective method to control SWI. A sensitivity analysis is conducted to investigate the effects of different external sources of recharge water and different recovery ratios of desalination plant on the optimal results

Brine Dispersion Modeling for Short-Term Low-Volume Desalination Plant of Deir Al Balah

Desalination of seawater is a promising alternative water source in coastal countries that suffer from depletion in conventional water sources. In Gaza Strip, the regional short-term low-volume (SLTV) seawater desalination plant was considered as an urgent solution to mitigate the suffering from water crisis. The plant will provide about 7.3 million cubic meters per year of freshwater for domestic uses. However, as a product from the reverse osmosis process, huge amount of brine, nearly 8.92 million cubic meters per year, with salinity reaches to 75,000 mg/L will be redirected to seawater. The arbitrary disposal of brine can have potential negative effects on marine ecosystems. To minimize the negative impacts of the rejected brine on marine environment under the change in the seawater characteristics over the four annual seasons, various outfalls configurations were simulated using CORMIX to study the efficiencies of their mixing behavior taking salinity variations as an indicator. The simulation results showed that the fanned-out unidirectional multiport outfall of option (7) is the optimal design configuration, where discharging the produced brine from the regional STLV plant via option (7) can meet the disposal standard at the boundary of regulatory mixing zone (RMZ) in the worst ambient condition of autumn at low astronomical tide by reducing the brine’s excess salinity at the edge of mixing zone to less than 1.25%(488 mg/L) above seawater salinity

Applying the Triangle Method for the parameterization of irrigated areas as input for spatially distributed hydrological modeling — assessing future drought risk in the Gaza Strip (Palestine)

In the Mediterranean region, particularly in the Gaza strip, an increased risk of drought is among the major concerns related to climate change. The impacts of climate change on water availability, drought risk and food security can be assessed by means of hydro-climatological modeling. However, the region is prone to severe observation data scarcity, which limits the potential for robust model parameterization, calibration and validation. In this study, the physically based, spatially distributed hydrological model WaSiM is parameterized and evaluated using satellite imagery to assess hydrological quantities. The Triangle Method estimates actual evapotranspiration (ETR) through the Normalized Difference Vegetation Index (NDVI) and land surface temperature (LST) provided by Landsat TM imagery. So-derived spatially distributed evapotranspiration is then used in two ways: first a subset of the imagery is used to

Wastewater Reuse in Gaza Strip

The Middle-East region has an arid climate with very scarce water resources, which are under heavy and increasing stress. Therefore, it is vulnerable to climate change that will eventually reduce rainfall, due to changes in oceanoatmospheric circulation patterns

محاكاة / تحسين لإدارة موارد المياه الجوفية في طبقة المياه الجوفية في غزة (الأراضي الفلسطينية) في ظل ظروف تغير المناخ

"The Gaza aquifer is the main source of water for agricultural, domestic, and industrial uses in the Gaza Strip. The rapid increase on water demand due to continuous population growth has led to water scarcity and contamination by seawater intrusion (SWI). urthermore, current projections of future climatic conditions (IPCC, 2007) point to potential decreases in available water, both inflows and outflows. A numerical assessment of SWI in the Gaza coastal aquifer under climate induced changes has been carried out by means of the CODESA-3D model of density-dependent variably saturated flow and salt transport in groundwater. The model was calibrated and validated in the period 1935-2010 and then used to simulate the response of the hydrological basin to actual and future scenarios of climate change obtained from different regional circulation models. The results clearly show that, if current pumping rates are maintained, seawater intrusion will worsen. To manage sustainable aquifer development under effective recharge operations and water quality constraints, a decision support system based on a simulation/optimization (S/O) approach was applied to the Gaza study site over the period 2011-2040, incorporating two conflicting objectives by a penalty method: maximizing pumping rates from the aquifer wells while limiting the salinity of the water withdrawn. The S/O approach is based on coupling the CODESA-3D model with Carroll’s (1996) Genetic Algorithm (GA) Driver. The resulting coastal aquifer management model identified the optimum spatial distribution of pumping rates at the control wells, providing for a general increase in water table levels and a decrease in the total extracted salt mass while keeping total abstraction rates relatively constant, with reference to non-optimized conditions."تعد طبقة المياه الجوفية في غزة هي المصدر الرئيسي للمياه للاستخدامات الزراعية والمنزلية والصناعية في قطاع غزة. أدت الزيادة السريعة في الطلب على المياه بسبب النمو السكاني المستمر إلى ندرة المياه وإدخالها في تسرب مياه البحر (SWI). علاوة على ذلك ، تشير التوقعات الحالية للظروف المناخية المستقبلية (IPCC ، 2007) إلى انخفاضات محتملة في المياه المتاحة ، سواء الداخلة والخارجة. تم إجراء تقييم عددي SWI في طبقة المياه الجوفية الساحلية بغزة في ظل التغيرات الناجمة عن المناخ من خلال نموذج CODESA-3D

Applying the Triangle Method for the parameterization of irrigated areas as input for spatially distributed hydrological modeling—Assessing future drought risk in the Gaza …

In the Mediterranean region, particularly in the Gaza strip, an increased risk of drought is among the major concerns related to climate change. The impacts of climate change on water availability, drought risk and food security can be assessed by means of hydro-climatological modeling. However, the region is prone to severe observation data scarcity, which limits the potential for robust model parameterization, calibration and validation. In this study, the physically based, spatially distributed hydrological model WaSiM is parameterized and evaluated using satellite imagery to assess hydrological quantities. The Triangle Method estimates actual evapotranspiration (ETR) through the Normalized Difference Vegetation Index (NDVI) and land surface temperature (LST) provided by Landsat TM imagery. So-derived spatially distributed evapotranspiration is then used in two ways: first a subset of the imagery is used to

A simulation/optimization approach to manage groundwater resources in the Gaza aquifer (Palestine)

Gaza aquifer is the main source of water for supplying agriculture, domestic, and industrial purposes in the Gaza Strip. Recently, the rapid increase on water demand to fulfill the needs of the continuous population growth made the aquifer overexploited, leading to huge crises of water scarcity and contamination by seawater intrusion. To relieve and narrow the huge deficit between water demand and supply, the use of artificial resources, such as stormwater and reclaimed wastewater, has been investigated. To manage sustainable aquifer development under effective recharge operations and water quality constraints, a decision support system based on a simulation/optimization (S/O) approach has been developed and applied to the Gaza coastal aquifer. The S/O approach is based on the coupling of the density-dependent variably saturated groundwater model CODESA-3D with the Carroll's FORTRAN Genetic Algorithm Driver. The optimization model incorporates two conflicting objectives using a penalty method: maximizing pumping rates from the aquifer wells while limiting the salinity of the water withdrawn. Two aquifer management models (with and without artificial recharge) have been considered for the inner region of the coastal aquifer within a 1 year time interval. Results of the no-injection optimization model identified the optimum spatial distribution of pumping rates at the 16 control wells, showing an average increase of 0.11 m (+9.2%) in water table levels and a marked decrease of 65% in the total extracted salt mass, while keeping the 99% of total abstraction, with reference to current non-optimized conditions. Results of the mixed injection-pumping optimization model identified optimum recharge locations among 9 configurations (3 different spatial locations and 3 rates of 0.5, 1 and 1.5 Mm3/year, respectively) and the spatial distribution of pumping rates at the wells, allowing to withdrawal the 95% of the total current pumping rate, while lowering the total extracted salt mass up to 25% and increasing water table levels in a range of 0.15-0.49 m, with reference to current non-optimized conditions. The last model allowed also to increase up to 20% the total pumping rate, while keeping the total extracted salt mass under 50% of current values with relatively stable water table levels. Further development is foreseen to extend the result to the whole aquifer system, including also economic costs into the multi-objective management model