Executive Summary

This report details a hydrogeological study of the Moghra aquifer in Egypt, a critical freshwater resource for regional development, aligning with the United Nations’ Sustainable Development Goals (SDGs). The primary objective was to simulate the impacts of extensive groundwater abstraction and subsequent saltwater intrusion using MODFLOW and SEAWAT models. This analysis is crucial for ensuring the long-term viability of water resources, directly supporting SDG 6 (Clean Water and Sanitation) and SDG 2 (Zero Hunger). Various abstraction scenarios for a 100-year cultivation project were modeled. Results indicate that for 1000 wells, abstraction rates of 1000, 1250, 1500, and 1750 m³/day/well would cause maximum drawdowns of 54, 66, 85, and 100 meters, respectively. These drawdowns represent a significant portion (18% to 30%) of the aquifer’s saturated thickness, posing a threat to sustainable water withdrawal (SDG 6.4). Increased abstraction substantially accelerates saltwater intrusion, a major challenge to water quality (SDG 6.3). At the highest abstraction rate, the 3500 mg/L salinity line advanced inland by up to 5.6 km. The study evaluated mitigation strategies, finding that a combined approach of artificial recharge and saline water abstraction is most effective in repelling the seawater interface. The findings provide a scientific basis for developing sustainable groundwater management policies in arid and semi-arid regions, ensuring water security for future generations.

1.0 Introduction: Aligning Water Management with Sustainable Development Goals

Groundwater constitutes a primary source of freshwater globally, with over 2.5 billion people dependent on it for daily needs. In arid nations like Egypt, its role is paramount for achieving key Sustainable Development Goals. This reliance, however, presents significant challenges to SDG 6 (Clean Water and Sanitation), as over-exploitation and climate change threaten both the quantity and quality of these finite resources. The Egyptian government’s development plans for the Western Desert, including the Moghra region, are heavily dependent on groundwater to support agriculture and new communities, directly linking water management to SDG 2 (Zero Hunger) and SDG 11 (Sustainable Cities and Communities).

A primary threat to coastal aquifers like the Moghra is saltwater intrusion (SWI), which degrades water quality and renders it unsuitable for consumption and irrigation, undermining progress towards SDG 6.3 (Improve water quality). Previous studies have modeled the Moghra aquifer, but a comprehensive analysis integrating various abstraction scenarios with SWI advancement and potential mitigation measures has been lacking. This study aims to fill that gap by providing an integrated simulation of groundwater flow and solute transport. The goal is to inform a management strategy that balances development needs with the imperative of resource preservation, thereby contributing to the implementation of SDG 6.5 (Integrated Water Resources Management).

2.0 Study Area: The Moghra Aquifer System

The Moghra aquifer is a vital water-bearing formation in Egypt’s northern Western Desert, targeted for a mega-cultivation project. It is primarily an unconfined aquifer composed of Miocene-era sediments, with an average thickness of 300 meters. The groundwater generally flows from northeast to southwest, discharging naturally into the Qattara Depression. The aquifer’s water quality is a significant concern for sustainable development, with salinity levels ranging from 1,000 ppm to over 12,000 ppm. This inherent brackishness, coupled with the risk of further salinization from SWI, presents a major challenge to its use for agriculture and domestic supply, directly impacting the feasibility of achieving SDG 2 and SDG 6 in the region.

3.0 Methodology: Modeling for Sustainable Groundwater Management

To assess the long-term sustainability of the Moghra aquifer, a three-dimensional numerical model was developed using the SEAWAT code, which integrates MODFLOW for groundwater flow and MT3DMS for solute transport. This approach allows for a comprehensive simulation of aquifer drawdown and saltwater intrusion under various management scenarios.

3.1 Model Construction and Calibration

The model domain was discretized into a grid of 136 rows by 110 columns, with six vertical layers representing the region’s hydrogeological formations. The model was calibrated using observed data for groundwater levels and salinity concentrations, achieving high correlation coefficients of 0.998 and 0.903, respectively. This robust calibration ensures the model’s reliability for predictive simulations aimed at sustainable resource management.

3.2 Investigated Scenarios for Sustainable Development

A series of scenarios were designed to evaluate the impact of the proposed agricultural development on the aquifer and to identify sustainable management pathways in line with SDG 6.4 (water-use efficiency and sustainable withdrawals).

• Abstraction Scenarios: Eight scenarios were tested, varying the number of wells (445 and 1000) and abstraction rates (1000, 1250, 1500, and 1750 m³/day/well) over a 100-year period.
• Mitigation Scenarios: To address the negative impacts of abstraction, particularly saltwater intrusion, three types of mitigation strategies were modeled:
  1. Abstraction of saline water near the coast.
  2. Artificial recharge with freshwater to create a hydraulic barrier.
  3. A combined approach using both saline water abstraction and artificial recharge.

4.0 Results: Assessing Impacts and Mitigation Strategies

4.1 Impact of Groundwater Abstraction on Aquifer Drawdown

The simulation results demonstrate a direct correlation between abstraction rates and aquifer drawdown, a key indicator for SDG 6.4 concerning water stress. Over the 100-year project period, significant declines in groundwater levels are predicted, particularly in the development area.

• 445 Wells Scenarios: Maximum drawdown ranged from 24 m (at 1000 m³/day/well) to 39 m (at 1750 m³/day/well).
• 1000 Wells Scenarios: Maximum drawdown increased substantially, ranging from 54 m (at 1000 m³/day/well) to 100 m (at 1750 m³/day/well).

The scenario with 1000 wells abstracting 1750 m³/day/well results in a 100 m drawdown, representing approximately 30% of the aquifer’s saturated thickness. This level of depletion raises serious concerns about the long-term sustainability of the agricultural project and its contribution to SDG 2.

4.2 Impact of Abstraction on Saltwater Intrusion (SDG 6.3)

Increased groundwater abstraction was found to significantly worsen saltwater intrusion, directly threatening water quality and the achievement of SDG 6.3. As groundwater levels decline, the natural hydraulic balance is disturbed, allowing saline water to advance further inland.

• Under steady-state conditions, the 3500 mg/L salinity line intruded up to 57.1 km inland in the western part of the aquifer.
• Increasing the abstraction rate from 1000 to 1750 m³/day/well (1000 wells scenario) caused this line to advance an additional 5.6 km in the central part and 4.4 km in the western part.
• Salinity in the development area is projected to increase dramatically, with some wells showing a doubling of Total Dissolved Solids (TDS) over the 100-year period, potentially rendering the water unsuitable for the intended agricultural use.

4.3 Evaluation of Mitigation Measures for Sustainable Water Quality

The study evaluated countermeasures to protect the aquifer, a critical action for ensuring clean water availability (SDG 6). The effectiveness of each strategy was measured by its ability to halt or reverse saltwater intrusion.

1. Saline Water Abstraction: Pumping saline water near the coast was effective at retracting the seawater wedge. At the highest rate, the 30,000 mg/L contour line retreated by up to 2.7 km.
2. Artificial Recharge: Injecting freshwater created a hydraulic barrier that pushed the saltwater interface back towards the sea. This method reduced salinity levels in the development area, with TDS in some wells decreasing by over 50%.
3. Combined Approach: The combination of saline water abstraction and artificial recharge proved to be the most effective strategy. This integrated method resulted in the greatest retreat of the saltwater interface (up to 2.5 km for the 30,000 mg/L line) and the most significant improvement in water quality in the development zone.

5.0 Discussion: Implications for Integrated Water Resource Management (SDG 6.5)

The findings underscore the critical trade-offs between agricultural development (SDG 2) and the sustainable management of water resources (SDG 6). Unchecked abstraction, while supporting short-term agricultural goals, leads to unsustainable drawdown and severe water quality degradation, jeopardizing the long-term viability of the entire development project. The mass balance analysis confirmed that higher pumping rates dramatically increase the influx of saline water into the aquifer system.

This necessitates an Integrated Water Resources Management (IWRM) approach, as advocated by SDG 6.5. The results show that relying solely on abstraction is not a sustainable strategy. Proactive mitigation measures are essential. The combined strategy of saline water abstraction and artificial recharge offers a viable pathway to decouple agricultural production from water resource degradation. This approach not only protects the freshwater portion of the aquifer but also manages the brackish water, turning a threat into a managed component of the system. Implementing such a strategy requires significant investment and policy commitment but is crucial for ensuring the resilience of both the ecosystem and the local economy.

6.0 Conclusion and Recommendations for Sustainable Development

This study concludes that the proposed large-scale agricultural development in the Moghra region poses a significant threat to the sustainability of the Moghra aquifer if managed improperly. High rates of groundwater abstraction will lead to excessive drawdown and severe saltwater intrusion, compromising water quality and undermining the goals of SDG 6 and SDG 2.

Recommendations:

• Adopt a Sustainable Abstraction Limit: The abstraction rate of 1750 m³/day/well for 1000 wells, resulting in a 100 m drawdown, should be considered the maximum allowable limit. The original plan to cultivate 170,000 feddans should be revised down to approximately 120,000 feddans to align with this sustainable limit.
• Implement Integrated Mitigation Measures: To protect water quality, a combined system of saline water abstraction near the coast and artificial freshwater recharge should be implemented. This is the most effective strategy for controlling saltwater intrusion and ensuring the long-term usability of the aquifer.
• Enhance Monitoring: Continuous monitoring of groundwater levels and salinity is essential for adaptive management. This data will allow for the timely adjustment of pumping and recharge rates to maintain the health of the aquifer.

By adopting these recommendations, decision-makers can steer the development of the Moghra region towards a sustainable path that balances economic growth with environmental stewardship, ensuring the achievement of the Sustainable Development Goals.

Analysis of Sustainable Development Goals in the Article

1. Which SDGs are addressed or connected to the issues highlighted in the article?

SDG 6: Clean Water and Sanitation

This is the most central SDG addressed in the article. The entire study revolves around the management of groundwater, a critical freshwater resource. It directly tackles issues of water scarcity in an arid region, the sustainability of water withdrawals, and the degradation of water quality due to saltwater intrusion.

• The article’s main objective is to “simulate the impact of groundwater abstraction and saltwater intrusion in the Moghra aquifer” to develop sustainable management strategies.
• It explicitly discusses the need to maintain the aquifer to “guarantee that there is enough water in it for continued growth.”

SDG 2: Zero Hunger

The article connects groundwater management directly to agriculture and food security. The abstraction of groundwater is for a “mega cultivation project” in Egypt, highlighting the dependency of food production on water resources.

• The study models abstraction rates for a “100-year cultivation project period.”
• It evaluates scenarios for cultivating large areas, such as “170 million feddans in the Moghra region,” and recommends reducing the cultivated area to ensure long-term water viability.

SDG 14: Life Below Water

The article addresses the interaction between land-based activities and marine environments. The over-abstraction of groundwater from a coastal aquifer directly causes saltwater from the Mediterranean Sea to intrude, impacting the coastal freshwater ecosystem.

• The study analyzes “saltwater intrusion (SWI),” which it defines as a “natural occurrence that causes seawater to displace the aquifer’s freshwater.”
• It models how different pumping rates cause the “advance of the seawater… inland to the Moghra aquifer.”

SDG 15: Life on Land

The study is set in Egypt’s Western Desert, an arid terrestrial ecosystem. The sustainable management of the Moghra aquifer is crucial for maintaining this ecosystem, preventing further desertification, and supporting the life that depends on this water source.

• The article emphasizes that groundwater is a “vital freshwater supply” in “dry and semi-arid areas like Egypt.”
• The outcomes are intended for “developing groundwater resources in both arid and semi-arid areas in a sustainable manner,” which is essential for protecting these vulnerable ecosystems.

SDG 11: Sustainable Cities and Communities

The article links the health of the aquifer to the viability of human settlements. The water is not just for agriculture but also for community development, making sustainable water management a prerequisite for sustainable communities.

• It is mentioned that “The Moghra aquifer provides the water needed for the population of Moghra, a recently constructed neighborhood.”
• The study’s goal is to ensure the aquifer is “well maintained to guarantee that there is enough water in it for continued growth.”

2. What specific targets under those SDGs can be identified based on the article’s content?

SDG 6: Clean Water and Sanitation

1. Target 6.3: By 2030, improve water quality by reducing pollution, eliminating dumping and minimizing release of hazardous chemicals and materials, halving the proportion of untreated wastewater and substantially increasing recycling and safe reuse globally.
   • The article directly addresses this by studying the deterioration of water quality due to saltwater intrusion, which is a form of contamination. It models salinity concentrations and evaluates mitigation measures like artificial recharge to improve water quality.
2. Target 6.4: By 2030, substantially increase water-use efficiency across all sectors and ensure sustainable withdrawals and supply of freshwater to address water scarcity and substantially reduce the number of people suffering from water scarcity.
   • The core of the study is to determine sustainable withdrawal rates. It models various “abstraction rate scenarios” to find an “optimum scenario” that prevents long-term depletion (“aquifer drawdown”) and ensures a sustainable supply for a 100-year project.
3. Target 6.5: By 2030, implement integrated water resources management at all levels, including through transboundary cooperation as appropriate.
   • The study is a practical application of IWRM principles. It uses advanced modeling tools (MODFLOW, SEAWAT) and scenario analysis to integrate hydrogeological factors with development plans (agriculture, community supply) to propose comprehensive management strategies.

SDG 2: Zero Hunger

1. Target 2.4: By 2030, ensure sustainable food production systems and implement resilient agricultural practices that increase productivity and production, that help maintain ecosystems, that strengthen capacity for adaptation to climate change, extreme weather, drought, flooding and other disasters and that progressively improve land and soil quality.
   • The article assesses the long-term sustainability of a large-scale agricultural project (“mega cultivation project”) dependent on a nonrenewable aquifer. It concludes that the original plan is unsustainable and “recommends reducing the cultivated area by 50%” to maintain the water ecosystem and ensure resilient agricultural practices.

SDG 14: Life Below Water

1. Target 14.1: By 2025, prevent and significantly reduce marine pollution of all kinds, in particular from land-based activities, including marine debris and nutrient pollution.
   • The study investigates how a land-based activity—groundwater abstraction—causes the intrusion of seawater into a coastal aquifer. This is a direct impact on the coastal zone environment, and the proposed mitigation measures aim to reduce this impact.

3. Are there any indicators mentioned or implied in the article that can be used to measure progress towards the identified targets?

Yes, the article provides several quantitative indicators that can be used to measure progress.

Indicators for SDG 6 (Clean Water and Sanitation)

• Groundwater Level Drawdown (Indicator for Target 6.4): The article quantifies the stress on the aquifer by modeling the drawdown in meters. For example, “the maximum simulated drawdown equals 54, 66, 85, and 100 m” for different abstraction rates. This directly measures the level of water stress.
• Salinity Concentration and Total Dissolved Solids (TDS) (Indicator for Target 6.3): The article uses salinity (mg/L) and TDS (ppm) as key measures of water quality. It provides specific values, such as initial salinity varying “between 1500 to 8000 mg/L” and models how salinity increases in wells over time, for instance, from “3875 to 7558 mg/L” in a worst-case scenario.
• Volume of Freshwater vs. Saltwater (Indicator for Target 6.6): Table 8 in the article explicitly calculates the “Areas and volume of saltwater, mixing, and freshwater zones” in km³ under different scenarios. This serves as a direct indicator of the health and status of the water-related ecosystem (the aquifer).
• Groundwater Abstraction Rate (Indicator for Target 6.4): The study is based on modeling different abstraction rates, such as “1000, 1250, 1500, and 1750 m³/day/well.” This rate is a primary indicator of freshwater withdrawal.

Indicators for SDG 14 (Life Below Water)

• Distance of Saltwater Intrusion (Indicator for Target 14.1): The article measures the impact of land-based abstraction by quantifying how far saltwater intrudes inland. For example, “The concentration line of 3500 mg/L intruded inland into the Moghra aquifer to a distance of 30.7, 52.7, and 57.1 km.” This is a direct measure of the impact on the coastal zone.

4. Table of SDGs, Targets, and Indicators

Source: nature.com