Geosynthetic clay liners, bentonite liners, clay liners, and compacted clay liners are critical materials in environmental engineering, designed to form robust barriers that prevent water and contaminants from migrating into surrounding soil and groundwater. Geosynthetic clay liners (GCLs) combine bentonite, a highly absorptive clay, with geotextiles or geomembranes, creating a flexible, lightweight material that expands upon contact with water to form a highly impermeable seal. This makes GCLs especially valuable in projects like landfill containment, mining, and wastewater treatment, where a quick-to-install yet highly effective liner is needed. Bentonite liners, made primarily of bentonite clay, use the unique self-sealing properties of this material to create a natural, water-impermeable barrier, making them ideal for a wide range of applications where containment reliability and easy maintenance are essential, such as secondary containment and hazardous waste storage. Clay liners as a category are valued for their low permeability and natural composition, which make them a strong option in situations where environmental considerations are a priority. Compacted clay liners (CCLs) consist of densely packed layers of clay compacted to a precise density to reduce permeability; this makes them a durable and effective solution in settings where locally sourced clay is available and a thicker, natural barrier is preferred. Each type of liner offers specific benefits depending on the project’s requirements, such as environmental regulations, installation complexity, or budget constraints. Geosynthetic clay liners are often selected for their flexibility and ease of installation, while bentonite liners and compacted clay liners provide dependable, naturally-derived containment solutions. Bentonite’s swelling capacity lends these liners an automatic sealing ability, and compacted clay liners, when properly installed, can achieve uniform, long-lasting coverage that effectively controls water and contaminant flow. Used in applications from landfill closures and reservoir lining to mining and infrastructure, these liners play a vital role in safeguarding environmental integrity by providing dependable containment solutions tailored to diverse engineering needs. compacted clay liner