How do engineers choose between a concrete gravity dam and an embankment dam?

Engineers select between a concrete gravity dam and an embankment dam based on several critical factors, including site geology, valley configuration, project purpose, and economic considerations regarding material availability and site accessibility.1

Choosing the Design

• Concrete Gravity Dams: These are typically preferred for blocking streams in narrow, mountainous gorges where the total volume of material required is limited. Because they rely on their own weight to resist water pressure, they are generally constructed on solid rock foundations. They offer greater resistance to minor overtopping than embankment dams, though they often require spillways to manage heavy floodwaters.12
• Embankment Dams: These are often chosen for broad, wide valleys where a long barrier is necessary. While they require a much greater volume of material, they are frequently more economical if suitable soil or rockfill is available near the construction site. Unlike concrete, embankment materials are more permeable and adaptable to foundation movements, though they require careful design to prevent erosion, seepage, and instability.134

Ultimately, the choice depends on balancing the structural requirements of the site with the cost-effectiveness of local resources.1