In acrh dam the load is distributed on both the side of dam 
as well as load is transfered in circular form on the 
ground. where as in gravity dam load is transfered strait 
to the ground. and kakrapar dam on river tapi is the 
exampal of the gravity dam.

the length of the arch dam is less and depth is high. the arch dam distributes on both side of dam.

Unlike the concrete gravity dams, arch dams use a special 
arch shape (curved toward upstream) to transfer the force 
to the two sides of the valley and the foundation. 
Idukki Dam is the first Arch Dam in India,
kakrapar dam on river tapi is the 
exampal of the gravity dam.