How do buttress dams resist the pressure of stored water?

Unlike traditional gravity dams, buttress dams do not rely solely on their own weight to resist the pressure of stored water. Instead, they utilize a design where the upstream face is inclined at an angle of approximately 25° to 45°.12

This inclination directs the thrust of the water toward the foundation rather than purely horizontally. The stability of the structure is primarily provided by the bracing action of the buttresses, which are located on the downstream side and serve to concentrate and support the load. By transferring the water's force to the foundation in this manner, buttress dams also benefit from experiencing smaller uplift forces compared to gravity dams.12