Factors affecting the crop's water footprint to optimize the water use efficiency in the Gaza strip, Palestine Open Access

Local water consumption is one of the most prominent global problems, as consumption has increased more than sixfold compared to the last century due to changing people's lifestyles, increasing population, and the growing need for water uses for various human purposes (Luan et al. 2018). Agricultural activities constitute the focus of blue water withdrawal, as irrigation is considered one of the most important means of consuming fresh water, which causes depletion and enormous pressure on water resources. Moreover irregular rainfall and longer periods of drought affect blue and green water. Obviously, this has had a negative effect on agricultural productivity (Rosa et al. 2020).

Sustainable management of water resources is an essential process to ensure the future of life on Earth (Mizyed et al. 2024a, 2024b). Hydraulic constraints, stochastic dynamics, and nonlinear effects constitute a challenge in environmental management for sustainable development (Li et al. 2019). Effective control of water resources constitutes an important part of the development process and therefore requires improving the efficiency of water use and developing the decision-making process based on available data to reach the best effective planning and water management policies (Xiang et al. 2021). Protection and sustainability of water resources are a must to overcome water scarcity (Mizyed 2025). This can be achieved by the development of strategies for managing water resources through effective and planned water utilization, water quality controls, improvement of water distribution, operational efficiency, and optimization of water resources (Yerli & Sahin 2021).

Optimization is the item of accomplishing the best possible result under given circumstances. The goal of all such decisions is either to minimize effort or to maximize benefit. The effort or the benefit can be typically stated as a function of certain design variables. Hence, optimization is the process of discovering the settings that give the maximum or the minimum value of a function (Jaslam et al. 2018). In agriculture, optimum utilization of resources involves decisions regarding what crops to produce, how much land to assign to each crop activity, and what strategy and combination of inputs to each crop so that the agriculture production is maximum. It is required that the accessible scarce resources should be used efficiently (Calicioglu et al. 2019).

The study by Alakbar & Burgan (2024) explored the potential of hydropower as a sustainable and economically viable solution to future energy crises and climate change. By utilizing long-term hydrometeorological data, the study developed a regional modeling approach to assess hydropower potential, emphasizing the role of basin characteristics and precipitation patterns in predicting streamflow variability under changing climate conditions.

The use of mathematical programming models is influential in studying the allocation of limited resources to provide required needs or improve the value of a particular objective function (RezaHoseini et al. 2020). A variety of perspectives discuss the development of models to include the analysis of irrigation water management and water use in agriculture in general, as it is concerned with changing crop patterns, profit maximization, irrigation scheduling, and water allocation among competing crops in a fixed area (Nazer et al. 2011).

The modeling is widely applied to agricultural problems to optimize crop patterns, and crop rotation plans, as well as water and land resource allocations, agriculture product transformation, several amounts of fertilizers, and so on (Dury et al. 2012). These problems can be resolved through the linear programming (LP) model, considered an easy way to make the right decisions rather than traditional methods, and this is why the model is crucial (Alotaibi & Nadeem 2021). To summarize the main reasons for using LP modeling to determine the best practices in the agricultural sector are as follows: increasing profitability, achieving food adequacy, optimal use of environmental resources, and overcoming ambiguity in the decision-making process through a set of additional constraints or conditional statements that must be satisfied (Jain et al. 2021). The study by Rantissi et al. (2024) provides valuable insights into climate change adaptation by emphasizing energy-efficient desalination and wastewater treatment as sustainable solutions for water scarcity in Gaza. By integrating renewable energy sources and optimizing desalination technologies, the approach reduces reliance on conventional energy-intensive methods, aligning with global climate resilience strategies.

The water footprint was introduced by Chapagain & Hoekstra (2004) as a consumption-based indicator of water consumption, measuring all direct and indirect freshwater consumption in the supply chain of a product, service, or production process (Mizyed 2024). This indicator defines each contribution to water consumption geographically and temporally, showing the amount of water consumed by source and the number of pollutants by type of pollution. It is a volumetric measure of water use and pollution (Aldaya et al. 2011). The components of a water footprint contain three different categories. Blue WF refers to both surface and groundwater consumption. Green WF discusses the consumption of green water resources, i.e. rainwater and soil moisture, while gray WF is defined as the quantity of fresh water required to absorb the pollution load, with concern to water quality standards in the region and natural context (Mizyed et al. 2024a, 2024b). Agricultural production contributes 92% to the total global footprint, according to Mekonnen & Hoekstra (2011). The study (Sharafi et al. 2024) employs CropWat software to assess crop water requirements (CWRs) under different climate scenarios, highlighting its role in evaluating agricultural water use efficiency. By analyzing water footprints (green, blue, and gray) across semidry, dry, and very dry climates, the research provides insights into sustainable crop selection amid climate change.

Varma et al. (2012) stated that the optimization model can help farmers in selecting the right crop at the right time and the optimum allocation of land and water to each of these crops to maximize the profit by taking into consideration the market prices, climate and irrigation facilities. Falkenmark (2007) suggested three options for capturing the additional water needed to meet the requirements of future food production: pursuing virtual water options, growing water productivity by reducing losses, improving the use of rainfall and expanding rain-fed agriculture.

Water-saving is an important goal of adjusting the planting structure in the Gaza Strip. In this paper, proposed scenarios are developed based on an assessment of existing resources, and quantitative analysis has been conducted to provide the most appropriate solutions. The optimal optimization of the water footprint of agricultural crops will be derived by studying the multiple influencing factors related to crop patterns, the required irrigation water, and the cultivated area which is applied in the process that ensures achieving profits, improving water productivity and promoting sustainable water management.

In terms of water quality, 97% of the available water is unfit for use due to contamination with nitrates, chlorine, and total dissolved salts, all of which exceed international standards. The average per capita consumption is 82 L per capita per day, according to the Water Authority (PWA 2021). Agricultural activities in Gaza consume more than 50% of the available water, as the cultivated area approached 162,000 dunums, distributed among the main categories: horticulture trees, field crops, and vegetables, in addition to greenhouses (PMA 2023).

The water footprint of Gaza Strip crops was estimated at 147 million m³, distributed among its three components (23% green, 56% blue, and 21% gray) (Mizyed et al. 2024a, 2024b). Horticultural trees contributed to the total water footprint by 62% (91.33 million m³), field crops by 5% (7.73 million m³), and vegetables contributed by 33% (47.5 million m³). Regarding the standard sustainability assessment classification, severe blue water scarcity occurred on the Gaza Strip (Mizyed 2024). This brief shows the Gaza Strip's need to reduce the blue water footprint due to the scarcity of available resources and the high dependance on it by more than 56% and the rising indicator of unsustainability, while at the same time maximizing the benefit from green water.

To optimize the blue water consumption, six scenarios were analyzed as follows:

(1) The first is to maintain the existing cropping patterns that are used as a reference to compare the item's water use, water productivity, and profit with the other scenarios. Then, (2) examining the effect of maximizing profit, (3) examining the effect of water requirement, (4) examining the effect of climatic parameters, (5) examining the effect of virtual water trade, and (6) examining the effect of satisfying food security to explore the influence of these various factors. This programming model focused on finding the optimal crop patterns in the Gaza Strip to reduce water use for irrigation while maximizing net benefits from irrigation. Thus, we seek to increase water productivity per unit of water.

The crops targeted by this model are those that are classified as the most water-consuming crops, which are categorized as having the largest water footprint; the cultivated areas are relatively large and generally contribute to achieving food security in the Gaza Strip. In terms of horticultural trees, the olive crop was chosen because its blue and green water footprint alone constitutes 39% of the water footprint of horticultural trees, as well as citrus and grapes, which constitute 26 and 7% of the water footprint of horticultural trees, respectively. These three crops amount to 72% of the water footprint for trees in the Gaza Strip. Regarding field crops in the Gaza Strip, wheat alone constitutes 67% of the water footprint of field crops. With respect to vegetables, tomatoes, potatoes, cucumbers, squash, and eggplant constitute the most important vegetable crops in the Gaza Strip, and they are centrally relied upon for food (Mizyed et al. 2025). These five alone constituted 62% of the green and blue water footprint in light of the great vegetable diversity in the Gaza Strip. These nine crops constituted 69% (79.8 million m³) of the total green and blue water footprint of the Gaza Strip (116 million m³ (Mizyed 2024). The various choices in vegetables could be controlled easily as a practice of agriculture and quantity of production in addition to a cultivation area setting. Moreover, there is still great social resistance from consumers and communities to vegetable crops that rely on treated wastewater for the irrigation, and this option would be somewhat acceptable for the irrigation of green fodder and horticultural trees. A number of researchers and experts in agricultural affairs in the Gaza Strip focus on increasing production from the land in tonnes/ha. This may seem feasible if the area allocated for agriculture is limited, but when there are also limited water sources, increasing water production is more important. Obviously, it is possible to reduce the blue water footprint in the agricultural sector (m³/ton) by increasing the productivity of blue and green water.

The two natural resource constraints are the total area of the agricultural land and the agricultural irrigation water available. Based on the endowment of agricultural resources, the current status of agricultural production, and regional development planning of the Gaza Strip, its natural resources, social needs, and ecological environment were taken as key constraints of the model.

• (1) Land constraint:

  

  (2)

  where Aa is the overall available area for agriculture in all zones (ha),
• (2) Water constraint:

  

  (3)

  where Wa is the total water allocated for agriculture (m³)
• (3) Local consumption constraint

  

  (4)

  where TD is the total local demand for the agricultural crops (ton)
• (4) Non negativity constraint

  

  (5)

The average water productivity in the agriculture sector can be expressed as the amount of agricultural product produced per unit of water. Lovarelli et al. (2016) defined the economic water productivity (P_WF) as the ratio of total summation benefit of a planting crop (SB_ij) to the total water footprint of a planting crop (WF_ij) in a specific area.

To increase the productivity of available water to the maximum possible extent, it is recommended that a unit of water be supplied to the most productive uses. This determinant is evident through the marginal value of water allocated for irrigation of crops, as it indicates the value of the last use of the water unit.

The methodology proposed by Hoekstra & Chapagain (2011) was employed. The CROPWAT model was used to calculate reference evaporation (ETo) and effective rain (P_eff) as well as CWR for different crops in the Gaza Strip. CROPWAT 8.0 is a program that permits the development of irrigation schedules for diverse management conditions and the calculation of scheme water supply for varying crop patterns. All calculation procedures used in CROPWAT 8.0 are based on the two FAO publications of the Irrigation and Drainage Series, namely, No. 56 ‘Crop Evapotranspiration – Guidelines for computing crop water requirements’ and No. 33 titled ‘Yield response to water (Allen et al. 1998; Doorenbos & Kassam 1986).

The models are solved mathematically using the LINGO program. LINGO is a simple tool that allows one to harness the power of linear and nonlinear optimization to formulate, solve, and analyze solutions to large problems precisely (LINDO 2024).

Data related to the governorates currently cultivated with various crops (A_ij), and the overall available agricultural areas (Aa) were obtained from the latest edition of the Palestinian Central Bureau of Statistics (PCBS 2023). Regarding the quantity of production for each crop, prices of crops (P_ij), yield (Y_ij), and total crop demand (TD) were quoted from the Ministry of Agriculture in the Gaza Strip.

The water requirement for each crop is determined by the calculation of crop evapotranspiration (ET_c) under standard conditions. ET_c is attained through the equation: ET_c = K_c*ETo that includes the effects of the various weather conditions incorporated into the potential evapotranspiration (ETo) and the crop characteristics into the K_c coefficient. The Penman equation is used to calculate the ETo in the Gaza Strip based on the meteorological status therein by the CROPWAT 8 model. The K_c values for each plant during the entire growth period were entered on a monthly basis, and each month was divided into three decades. The production cost includes the capital costs and the running costs. The capital cost includes the (initial) irrigation system cost. The running costs include cultivation, fertilizers, pesticides, seeding, and labor costs. The existing data for the variable cultivated cost (Cc_ij) was collected through a semi-structured interview with officials in the Ministry of Agriculture.

The first scenario describes the current situation of the agricultural patterns of the targeted crops from several aspects, namely the water footprint of agricultural crops, the cultivated area, net profit, water productivity, and the amount of production. The necessary data were collected to evaluate the reality of the current sector, and it is used as a reference point to compare other scenarios. Table 1 shows the current results.

It is clear from the table above that the water footprint of the targeted crops amounted to 80.23 million m³ of blue water only, according to the quota approved by the Ministry of Agriculture and the Water and Environment Authority in the Gaza Strip (WEQA 2022). Olives and citrus constitute 56% of water consumption alone, due to the surface irrigation method and the spread of these two crops in large areas. The total profit amounted to $111 million for all crops, achieved from the production of approximately 275,000 tons. Tomato and potato crops accounted for 53% of total profits. The wheat and grape crops do not achieve profits, but rather suffer losses due to the weak productivity rate per hectare of wheat, as well as the fluctuation of the amounts of rain that falls on the Gaza Strip, in addition to the high cost of the grape crop cultivation process.

Regarding blue water productivity, its average in the current situation reached 1.38 $/m³, where the eggplant crop achieved the highest productivity with a value of 7.97 $/m³, followed by tomato and cucumber crops with a value of 5.5 $/m³, and other crops recorded limited values for water productivity, which reflects an important indicator of efficiency absence of water used in irrigation, and the weakness of agricultural productivity, by way of developing water productivity considered a decisive factor in improving the agricultural situation. Regarding the use of green water, it has not been calculated in studies specific to the Gaza Strip, and the amount of its consumption in the Gaza Strip has not been determined by official institutions.

The Gaza Strip is characterized by agricultural diversity for all crops and achieves self-sufficiency in a number of targeted crops. From this diagnosis of the agricultural water reality, it could be useful to study the use of the agricultural water footprint as an effective tool in managing water resources and its impact on improving this reality.

This scenario is based on applying the plant's real requirement for water according to what was researched in this study and through water modeling over the CROPWAT program. For all agricultural studied crops, blue and green water withdrawals are determined, as combined in Table 2.

The results show that the blue water footprint reached 58.91 million m³, with a decrease of 21.31 million m³ (26.5%) of consumption in the current situation described in the first scenario. For illustration, the olive crop had a difference of 2.5 million m³, as well as citrus crops by 3 million m³. This amount of water was supplied in excess of what crops needed at the irrigation process, as the irrigation process does not depend on scientific methods but rather on inherited experience. Also, there are primitive methods in the irrigation, not smart methods, as well as the letdown of its efficiency that agree with (Abioye et al. 2020)

This scenario also determined the consumption of green water 20.8 at million m³, as it was not considered in the previous scenario. It provides scope for studying it and ways to take full advantage.

Along with this, there is an improvement in net profits, with an increase of $ 6.4 million (5.45%) over the reference situation, taking into account that there are crops that still do not achieve economic returns but are instead losing. For the reasons of continuous theoretical losses, it's clear that many farmers depend on illegal and non-licensed wells. They do not pay the cost of water, nor are they included in their profit and loss accounts except for very limited costs. With regard to water productivity, it is noted that the average total water productivity increased from 1.38 $/m³ in the first scenario to 1.99 $/m³ in this scenario. This is an extremely important goal, in light of the limited water resources in the Gaza Strip as for instance, the productivity of the eggplant crop reached the highest value at $17.5/m³ while in the first scenario just 8 $/m³, followed by vegetables such as tomatoes, potatoes, and cucumbers in the range of 7 $/m³, while fruit trees remained with low productivity, below 1 $/m³. This is because the amount of water consumed is relatively large compared to other crops, and production is limited.

Ultimately, it could be commented that there is an urgent need to control water consumption in agriculture, adopt efficient irrigation systems, and focus on agriculture with high water productivity, such as eggplant, tomato and potatoes. Therefore, applying this measure alone would be enough to reduce (17.4%) of total public consumption (122.6) in the agricultural sector.

This scenario was built on the basis of the effect of the amount of rain and weather conditions on the location of agriculture, as the Gaza Strip, despite its limited area, observes fluctuations in rainfall amounts and relative diversity of climatic conditions. The average depth of the rain amount in the north of the Strip was 425 mm, while the average in Rafah, in the south of the Strip, is 241 mm. This variety casts a shadow on the aridity index.

Based on the AI, this scenario discussed the comparison between the amount of water consumed for growing crops in the northern Gaza Strip, as well as in the southern regions of the Strip, and its impact on the green and blue water footprint. The water footprint of crops was calculated using the CROPWAT 8 program through climate data from the northern stations, Beit Hanon, Beit Lahia, Jabalia, and Om Nasser; it was included to calculate the evapotranspiration rate, which amounted to 4.07 mm/day, as well as determine effective rain. The following Table 3 shows the output results of the water footprint.

A fragment of the crops depends on rainwater; it is classified as rain-fed agriculture. It is demonstrated in areas where groundwater suitable for irrigation is not available, as some crops require water with a low percentage of salts. However, the rains in the sector are limited to a specific time from October to March and fluctuate from year to year as a result of climate change affecting the region.

Table 3 shows the effective feasibility of where the crop is grown, as the total blue and green footprint of growing these crops in the northern region amounted to 72.92 million m³, which is 6.86 million m³ less than the second scenario, at a rate of (8.5%). Here, the greatest benefit from increasing rainwater utilization and thus the green footprint appears, as the green water consumed increased from 20.86 million m² to 24.67, by 18.2% (3.81) million m³. It is also noted that the crops’ need for blue water has decreased significantly from 58.9 to 47.2 million m³, a difference of 11.7 million m³, a relatively high rate of 19.8%. It can be concluded that there are some crops, especially rain-fed crops, such as wheat and some beech vegetables, that are cultivated in the north much better than their cultivation in the south of the Strip and save a large portion of water consumption, which is in line with the study of Bhatia & Rana (2020). This conclusion requires the local decision-maker to build on it to redevelop agricultural patterns in the Gaza Strip.

With regard to estimating water productivity, it is noted that there is an increase in the productivity of a unit of water compared to the first and second scenarios, as the total average productivity reached 2.6 $/m³ within the increase of 1.38, 1.99 $/m³ over the first and second scenarios, respectively. The net profit in this scenario would have been 125.42 million dollars, an increase from the second scenario of $8 million.

There are some social obstacles facing this scenario. It is difficult for farmers to replace all vegetables with only one type or another place and to limit it to specific varieties, as there are many regions famous for their type of agriculture, and this faces difficulty for farmers accepting this idea since the agriculture source is part of people's lives and culture. This agrees with the study (Alakbar & Burgan 2024) that stated by utilizing regional models, it contributes to sustainable water resource management and aligns with climate adaptation strategies.

Based on the fact that the Gaza Strip is a region with a high population density and its land and water resources are limited, it cannot achieve self-sufficiency in a number of agricultural crops, and therefore it resorts to importing crops from some neighboring countries or from the occupation. This scenario is based on replacing water-consuming crops with a high-water footprint with crops that can be imported from abroad and saving water for other uses. The functional goal of this scenario is to predict what amount of water will be reduced through the process of relying on exports, with an important constraint, which is that all lands are occupied by agriculture.

One of the directions of this study is to study the water consumption of agricultural crops, and therefore these imported crops are classified as virtual water entering the Gaza Strip. On the other hand, what Gaza exports represent virtual water leaving the Strip, even though the export process from the Gaza Strip fluctuates and is expected to be unstable as a result of the political circumstances and the complete Israeli occupation control over it.

Regarding the crops studied during the specified period, according to data from the Ministry of Agriculture, there was an excess in eggplant production estimated at 14,000 tons, potatoes at 10,200 tons, grapes at 3,800 tons, and olives at 4,200 tons, while there was a deficit in squash crops at 2,000 tons, and cucumbers at 11,300 tons. Besides, the deficit in the wheat crop cannot be filled if the domestic product does not cover 2% of consumption, so it can be assumed that the current wheat production will be doubled by 100%, and thus there will be a deficit of 4,300 tons, while the tomato and citrus crops are self-sufficient. Table 4 presented the green and blue water footprint for the excess and deficit crops using CROPWAT 8.

Table 4 shows that if the Gaza Strip exports its surplus crops, it will lose 12.45 million m³, while if it imports the shortfall, it will save 5.47 million m³ (1.96 green and 3.52 blue), which is a relatively small amount, meaning that the loss is 6.98 million m³, and this is a negative indicator in terms of water consumption. As there is the possibility of achieving self-sufficiency in all crops. If land is reallocated to crops, this option contributes to reducing water consumption and works to achieve self-food security for the residents of the Gaza Strip through these crops.

This scenario works to save an area of land that was cultivated with crops of wheat, zucchini, and cucumbers, with an area of 1,999 hectares. Therefore, the size of the cultivated area will be 8,848 hectares. Likewise, the production of these crops will decrease by 17,600 tons, bringing the total production to 257,391 tons.

This calls for the development of an agricultural strategy for crops in the Gaza Strip that studies export and import options, especially if we take into account the complex conditions that this system is going through in our reality today due to the Israeli occupation. It may often resort to closing the crossings, and there becomes a surplus in many crops; thus, their prices fall, and economic damage is caused to farms and the agricultural sector.

This option may be effective in places where water scarcity is high and water exports are clearly free without occupation restrictions, as stated in Hoekstra's study (Hoekstra & Chapagain 2007), where they argue that virtual water trade through crop trade is an option to address water scarcity.

In this scenario, blue water productivity is similar to the second scenario since the blue water footprint was not greatly affected (53.8 Mm³ less than scenario 2), and therefore the average productivity is 2.1 $/m³.

Conversely, Jordan has developed a policy based on the principle of reducing the export of water-intensive crops while at the same time achieving a high income, i.e., its water productivity is high in $/meter³ (Council 2004). In other words, importing agricultural crops from another country may be more efficient than producing them locally, whether in terms of water or financial cost. As a replacement for relying on this method on a large scale may result in the loss of a number of jobs for workers in the agricultural sector, the decision-maker is required to provide alternatives for these spaces.

In this scenario, the virtual water concept was presented in a comparison between the exported quantities and the imported quantities of crops embodied water. As a result of this diagnosis and through applying the water footprint, the Gaza Strip is not suitable to apply this option for the studied crops.

The starting point for this scenario is based on studying water consumption if all crops in the Gaza Strip were grown in sufficient quantities to achieve food security. The current population number for the year 2023, as well as the consumption rate for each crop, was estimated according to the Ministry of Agriculture and the Palestinian Central Bureau of Statistics (PCBS 2023).

Table 5 shows the blue and green water footprint of studied crops, net benefit, blue water productivity, total local demand to satisfy food security, and the new required land area to produce the needed crops.

It is clear from Table 5 that the area allocated for cultivated studied crops and at the same time achieving self-sufficiency amounted to 12,348 hectares, with an increase of 1,510 hectares (15,100 dunums), meaning an expansion of agricultural land by 13.8% compared to the existing situation. This required area is available according to the reports of the Ministry of Agriculture. It is noted that there is a slight decrease in net profits of $2.4 million compared to the first scenario (111 million). However, another benefit is achieved, which is doubling the production of wheat compared to the values in the first scenario.

Achieving self-sufficiency has reached 268,400 tons of all crops as well as doubling the current wheat production. This scenario achieved an acceptable average productivity compared to other scenarios, as it reached $3.91/m³, and the crops that constitute a loss, such as grapes, have to adjust their selling price to take into account their high operational cost. It is practically acceptable and applied in light of achieving self-sufficiency.

This scenario provides a clear benefit in the issue of maximizing the use of green water (rainwater), as in this way it provides the highest percentage of green water with a value of 27.5 million m³, which is higher than all the proposed scenarios. Also, reducing dependance on blue water became clear through 50.79 million m³, which is less than the current situation by approximately 30 million m³.

LINGO software is used to perform the optimization task of each individual objective: net benefit, agricultural production, and area, as well as water consumed as a binding constraint, which is performed with a LP model.

The best area and pattern for cultivating the land were calculated to achieve the highest profit. The output results show that the eggplant crop was valued at 621 million dollars, and all the land was cultivated with the same crop, and no other type of crops were grown in addition to the production amounts of the same crop, which is 1.04 million tons. The green and blue water footprints of this crop scenario are 20.8 and 32 million m³, respectively, and the total WF is 52.8 million m³, so the blue productivity is 11.7 $/m³. Similar results is approved by Varma et al. (2012).

This is a result that faces a clear social obstacle in terms of its acceptance by farmers or its suitability for implementation in the Gaza Strip, which requires a complete diversity of crops and not being dependent on one crop that is difficult to export due to political factors. If an agricultural problem occurs as a result of the spread of any disease or insect that affects productivity, or there is an obstruction to exports, it will cause an economic catastrophe. In addition, the Gaza Strip will become completely dependent on importing crops. This contradicts the policy of the Ministry of Agriculture, which works to replace imports and promote local products. In contrast, the process of optimizing the land area shows that an area of 5,363 dunums is reduced from the area allocated for cultivation during water constraints.

The following Table 6 shows the most prominent results of previous scenarios for employing the concept of the blue and green water footprint to reach a sustainable framework for water resources management.

It is noted that before employing the concept of the blue and green water footprint, as in the first scenario, the consumption of the crops targeted by the study amounted to 80.23 million m³ of blue water from the groundwater reservoir, without taking into account green water.

The safe withdrawal of groundwater from the Gaza Strip for all human purposes and uses, not just for agriculture or for studied crops, must not exceed 80 million m³, as stated in the report of the Ministry of Water and Environment (WEQA 2022).

This is an indication of the massive depletion of these agricultural crops from the aquifer, the only available water resource. In addition, the economic productivity index per water unit for these crops is generally low, with an average of $1.38/m³. This stems from the agricultural practices followed in irrigation, excessive use of water, and the failure to follow any scientific and systematic approach in the irrigation process.

Through the use of the CROPWAT program as applied in the second scenario, it was observed that there was a clear reduction in the water used compared to the first scenario, as the reduction of blue water reached 21.3 million m³ (26.5%), likened to the first scenario. The benefitted volume from green water was also determined, which amounted to 20.78 million m³. This aligned with the findings of Sharafi et al. (2024), which reveal drier climates necessitate a shift toward low-water-demand crops like almonds and pomegranates, while high ET_c crops such as maize and alfalfa pose greater water management challenges. These insights underscore the need for adaptive agricultural strategies to ensure water-efficient crop selection in arid regions.

Furthermore, there was an improvement in the value of the economic productivity index, as it reached $1.99/m³. If we review the results of each crop, we notice the fundamental difference between the two scenarios for each crop. Therefore, these values obtained from modeling were included as a starting point in the other scenarios due to their clear effect in reducing consumption. This result requires policy creators and decision makers in local authorities to allocate water quotas for each crop and apply the use of computerized modeling, such as the Food and Agriculture Organization FAO program, in order to maximize agricultural water unit productivity and calculate the optimal consumption of irrigation water.

The locations of grown crops and their impact on water consumption were also studied based on the drought index, and the extent of optimizing potential from rainfall amounts and variations in weather conditions was considered. The third scenario revealed the maximizing of the harvested green water and reducing the footprint of blue water by changing the places of planting crops, as it was benefiting from 18.2% (3.81 million m³) in crop cultivation in the north of the Strip compared to the south, as well as saving an amount of 10.7 million m³ of blue water (19.8%).

Through this concept, it promotes the development of a path to guide farmers to adapt where the crop is grown to achieve the highest productivity. It agrees with (Rantissi et al. 2024) findings that highlight the necessity of sustainable resource management to mitigate the impacts of climate change on water and energy security.

According to a study by Al-Najar (2019), that noticed an increase in winter crops planted in the south of the Gaza Strip, which are areas that are classified as arid, while if planted in the north of the Gaza Strip, the amount of water used will decrease significantly. The results of the wheat crop are the best evidence of this, as it alone provides 2.01 million m³ of blue water as well as gains 1.43 million m³ of green water, and this principle is confirmed by the study (Wankhade et al. 2012). Therefore, it is possible to analyze and study the climate data of all meteorological stations and the results of the analysis of water modeling for agricultural crops in this study to develop a plan for the appropriate places for each crop.

The concept of virtual water trade in crops in the Gaza Strip was also examined through the fourth scenario, and the study concluded that this concept may be influential in other countries, but its impact is limited in the Gaza Strip, with the exception of the wheat crop, because it requires very large areas, up to several times the area of the Gaza Strip, to achieve the local demand. Thus, the virtual water in the wheat crop achieves a clear advantage for the Gaza Strip.

The feasibility of the concept of virtual water was also compared in other studies in neighboring countries, and its effectiveness was proven in them, but in Gaza, its effect is limited and causes a loss of 6.98 million m³, in addition to the political conditions and control of the crossings by the occupation, which constitute the most prominent factor in the limitation of this concept, while in a country with sovereignty, crossings, and freedom, it is possible to achieve greater sustainability of the country's water resources.

The scenarios also mainly touched on the idea of achieving the best profits. The eggplant crop achieved very large profits, as well as a significant saving in the blue and green water footprint compared to other scenarios, without any other crops being planted, meaning that the entire area would be planted with the same crop.

Focusing attention on financial profits only seems good from a theoretical point of view, but there are political, social, and logical obstacles to its implementation in the Gaza Strip. It may turn from a point of strength with these profits into a point of loss. For example, if its exports abroad are stopped, a huge loss will occur. It is in conflict with the Ministry of Agriculture in relying on the national product and achieving self-sufficiency (PMA 2023).

The decline in agricultural water resources in the Gaza Strip, a region with a semi-arid climate, is closely linked to climate change and rapid population growth. The results of this study indicate that it has a positive impact on climate change, as water modeling has driven to reduction of water consumption in irrigation, and the effect of the location of crop cultivation has led to increasing the productivity of the water unit, in addition to maximizing the benefit from green water, which leads to preserving water resources in the Gaza Strip, as agreed with Sharafi et al. (2024).

The reasons for this choice can be summarized in the following points:

• This scenario provided the highest use of rainwater and soil moisture as green water compared to all the mentioned scenarios, which allows for the best employing of rainwater as a renewable natural source of water, as it reached 27.84 million m³, with an increase of 7 million m³ (33%) compared to modeling outputs of green water footprint for crops in the existing situation (20.87 million m³). This has a positive impact on reducing the demand for debilitating blue water and enhancing sustainability which agrees with Hogeboom (2020).

• One of the fundamental results provided by this scenario is the optimization of blue water footprint, as it stipulates that the production of these crops requires 50.79 million m³, which is less than the first scenario, which represents the current reality of irrigation quantities in the Gaza Strip, by 29.4 million m³, it signifies a 37% reduction of water consumed. Furthermore, it represents 24% of the volume of general agricultural consumption in the Gaza Strip (122 million m³), and when compared to the modeling results for the second scenario, it reduces consumption by 13.7% (8.11 million m³). This path in decreasing water footprint agrees with the study of Vanham & Bidoglio (2013).

• This scenario improves the economic productivity of water units, especially in vegetable crops, as it reached 18.5 $/m³ for eggplant, followed by potatoes at 13.9 $/m³, tomatoes at 9.25 $/m³, and cucumbers at 8.74 $/m³, which are good percentages which agree with the study (Al-Najar 2019). Raising productivity per unit of water is an important point in reducing the amount of water withdrawal, and it can also be improved further by choosing the most appropriate place for agriculture, as explained in the third scenario, and by developing agricultural practices in irrigation and using more efficient systems, as stated in the studies by Al-Said et al. (2012), Anstalt (2013).

• This scenario requires a larger area than the current land allocated for agriculture, expanded to 15,100 dunams. However, this is an available area in the Gaza Strip, where there are areas not exploited by agricultural work that can be reclaimed and cultivated according to the reports of the Ministry of Agriculture, and this is what enhances general productivity, as stated in Sofi et al. (2015). Also, the increase in available land could constitute an opportunity to employ more workers and contribute to reducing the widespread unemployment rate in the Gaza Strip.

• Another consideration emerged in this scenario, which is achieving self-sufficiency and reliance on local products, with the ability to produce 268 thousand tons, which is what the Gaza Strip needs of these crops. This importance is heightened in view of the specificity of the political reality of the Gaza Strip and the continued policy of the imposed blockade and control of exports and imports from the occupation. Therefore, there was a need for self-reliance and achieving food and water security, and this is fully consistent with the strategic plan of the Ministry of Agriculture, and a similar approach has been achieved in the Iranian strategic study plan (Zarezadeh et al. 2023).

• This scenario also highlighted the importance of the financial return and made a helpful factor in adopting it, as it achieves profits that are appropriate and close to the other scenarios, 112.9 million dollars, while scenario 6 was excluded due to its inapplicability in the Gaza Strip. Therefore, the financial increase constitutes an incentive and support for implementing the scenario. In addition, it is possible to improve financial returns through agricultural practices related to resource development and determine the most effective arrangement of crops that will generate the highest possible sales, as stated in an Egyptian study (Osama et al. 2017).

• An important point that can be added is that the diversity of methodologies used in this scenario gives the greatest credibility and realism to the research results. This option is based on the CROPWAT program to determine the exact water need of the plant, as well as the Hoekstra methodology to determine the green and blue water footprint, which is an approach approved in similar studies (Hoekstra et al. 2011). It is also combined with the concept of virtual water that has been applied to the wheat crop. This diversity is useful and can be built upon to derive a strategy to utilize the water footprint in a scientific and systematic manner, as stated in the China study (Wu et al. 2022).

Based on the above and through the principle of the agricultural water footprint, it is worth employing WF as a tool that supports the decision and policy maker in building future and strategic plans, according to scientific and methodological foundations, and on the path to achieving sustainability of the water resources in the Gaza Strip, as well as achieving food security.

The influences of several factors on optimizing the water footprint in the Gaza Strip have been verified. The results showed the importance of determining the actual water requirements for irrigation through the CROPWAT program since there is water depletion over traditional methods. The effect of selecting the crop cultivation place was evident, as it requires planting crop fields in the rainiest areas to maximize the efficiency of green water, contrary to what is common in the current situation. The results showed the futility of using the concept of virtual trade in the Gaza Strip, despite its effectiveness in other places, due to the surrounding political realities. The ideal scenario was to change the agricultural pattern to achieve food security because it includes the greatest benefit from green water and savings from blue water. This study was limited to the blue and green water footprint and did not include the gray footprint. The target crops can also be expanded to study other crops. The water footprint has been a unique tool in diagnosing many water crises related to the Gaza Strip. This opens the door for further studies in the optimization process and transitions to modern irrigation methods to provide more sustainable and effective solutions.

All relevant data are included in the paper or its Supplementary Information.

The authors declare there is no conflict.