Journal of Coastal Zone Management

Exploring Coastal Aquifers: Importance, Challenges, and Sustainable Management Practices

Francisco Ther^* Department of Social Sciences, University of Los Lagos, Osorno, Chile
^*Correspondence: Francisco Ther, Department of Social Sciences, University of Los Lagos, Osorno, Chile, Email:

Received: 30-Apr-2025, Manuscript No. JCZM-25-29424; Editor assigned: 02-May-2025, Pre QC No. JCZM-25-29424; Reviewed: 16-May-2025, QC No. JCZM-25-29424; Revised: 23-May-2025, Manuscript No. JCZM-25-29424; Published: 30-May-2025, DOI: 10.35248/2473-3350.25.28.676

Description

Coastal aquifers are vital groundwater reservoirs located near coastlines, where fresh water is stored beneath the earth’s surface in porous rock or sediment formations. These aquifers serve as essential sources of freshwater for many coastal communities around the world. They provide water for drinking, agriculture, industry and ecosystem support. Due to their location, coastal aquifers are influenced by both terrestrial and marine processes, which create unique challenges and dynamics. Understanding coastal aquifers, their behavior and sustainable management is crucial for preserving this critical resource in the face of increasing population pressure, climate change and environmental degradation.

The structure of coastal aquifers typically includes layers of permeable materials such as sand, gravel, or limestone that allow water to flow and be stored underground. Freshwater in these aquifers originates from rainfall that infiltrates the soil and percolates down to recharge the groundwater system. Because of the proximity to the ocean, coastal aquifers often exist as a delicate balance between freshwater and saltwater. This interface between freshwater and seawater is known as the freshwater- saltwater boundary or the saltwater intrusion zone. The dynamics of this boundary are influenced by the pressure differences between freshwater, which is less dense and denser seawater.

Saltwater intrusion is a significant issue affecting coastal aquifers. When groundwater is extracted excessively for human use, the water table within the aquifer drops, reducing the pressure that keeps seawater at bay. This allows saltwater to move inland into freshwater zones, contaminating wells and making the water unsuitable for most uses. Saltwater intrusion can cause severe impacts on drinking water supplies, agricultural irrigation and natural ecosystems dependent on fresh groundwater. It is a growing problem in many coastal regions due to rising water demand, population growth and climate- related factors such as sea level rise.

Sea level rise caused by climate change exacerbates saltwater intrusion by increasing the hydraulic pressure of seawater against coastal aquifers. Higher sea levels can push the saltwater boundary further inland, reducing the volume of fresh groundwater available. In addition, extreme weather events like storms and hurricanes may increase saltwater flooding, leading to episodic contamination of aquifers. These changes threaten the sustainability of coastal groundwater resources and highlight the urgent need for adaptive management strategies that consider both current and future conditions.

Another challenge to coastal aquifers is contamination from human activities. Pollution from agricultural runoff, industrial waste, septic systems and urban development can degrade groundwater quality. Nutrients such as nitrates and chemicals like pesticides can infiltrate aquifers, posing risks to human health and ecosystems. In coastal areas, the interconnectedness of groundwater and surface water means that contamination can quickly spread and impact marine environments, including coral reefs and fisheries. Protecting coastal aquifers requires careful monitoring, pollution control and land-use planning to prevent contamination.

Recharge of coastal aquifers depends heavily on rainfall patterns, which may be altered by climate variability and human modifications to the landscape. Reduced recharge due to drought, urbanization, or changes in vegetation cover can lower groundwater levels and increase vulnerability to saltwater intrusion. Conversely, excessive recharge from stormwater or irrigation can cause waterlogging and mobilize contaminants. Understanding these complex hydrological processes is essential for managing groundwater sustainably in coastal zones.

Sustainable management of coastal aquifers involves balancing water extraction with natural recharge and protecting water quality. One key approach is the implementation of controlled pumping strategies that prevent over-extraction and maintain hydraulic pressure to inhibit saltwater intrusion. Artificial recharge techniques, such as injecting freshwater or directing stormwater into recharge basins, can help replenish aquifers and restore balance. In some cases, physical barriers or subsurface injection of freshwater are used to create hydraulic barriers against seawater intrusion.

Integrated Water Resource Management (IWRM) is vital for coastal aquifer sustainability. This approach coordinates groundwater management with surface water use, land use planning and environmental conservation. Policies and regulations that promote efficient water use, pollution prevention and ecosystem protection support the long-term health of coastal aquifers. Community involvement and stakeholder engagement are also important to ensure that water management decisions are socially equitable and environmentally sound.

Advancements in technology have improved the monitoring and understanding of coastal aquifers. Tools such as geophysical surveys, groundwater modeling and remote sensing provide detailed information on aquifer structure, flow patterns and salinity distribution. These data help scientists and managers predict responses to changes in extraction rates, sea level and climate conditions. Real-time monitoring networks enable early detection of saltwater intrusion and contamination, allowing timely interventions to protect water quality.

Case studies from around the world demonstrate the importance of protecting coastal aquifers. For example, many island nations and arid coastal regions rely heavily on groundwater for freshwater supply. In places like California, Florida and parts of Australia, saltwater intrusion is a persistent threat requiring ongoing management efforts. Innovative projects incorporating artificial recharge, conservation and community education provide models for addressing these challenges effectively.

Conclusion

In conclusion, coastal aquifers are critical freshwater resources that support human populations, agriculture and natural ecosystems along coastlines. Their unique position at the interface between land and sea makes them vulnerable to saltwater intrusion, contamination and climate change impacts. Sustainable management requires an integrated approach that balances water use with recharge, protects water quality and involves stakeholders. Advances in technology and increased awareness provide opportunities to safeguard coastal aquifers for present and future generations. As coastal populations grow and environmental pressures intensify, the careful stewardship of these groundwater systems will be essential for ensuring resilient and healthy coastal communities.