The buttress dam posses an upstream that is watertight which is inclined at angle of 25 to 45 degrees. This arrangement hence make the thrust of the water inclined towards the foundation. With technology, buttress dams were built with thin buttresses made out of reinforced concrete. The buttress dam use large formwork and steel reinforcement which make it less demanded. With greater heights, the buttress dam become less slender.
Compared to gravity dam, the buttress dam make use of less concrete. This is because there are spaces between the buttresses. The stability of the buttress dam depends on the bracing action from the buttresses. The buttresses are the structural elements onto which most load is concentrated.
Buttresses dams are suited to areas with wide or narrow valleys like gravity dams. The buttress dam requires solid foundation with a bed rock.The water from the downstream pushes the dam which is resisted from toppling by the opposite force exerted by buttresses. The weight of the buttress dam also try to push the dam down the ground.