The scour downstream spillways can endanger the stability of the dams. Hence, determining the
scour depth downstream of spillways was vital importance which scours holes formed around and
near the foundations of spillways can endanger the stability of dams and may lead to their failure.
So, this paper, investigate the scour downstream contraction stepped spillways. The experimental
flume used 16.2 m length, 66 cm width and 65 cm depth. The used number of stepped spillways
was 4 Sep, contraction ratio was 60% from flume width and the opening area in breaker 10% from
the breaker area on all sides putting in down of breakers. The breaker used above the stepped
spillway with different shapes of openings as rectangle, triangle and trapezoidal and different
numbers by 2, 4, 6 and 8 of beakers. The divergent angle changes by 45º, 30º, 15ºand 10º. The
results were showed that the best numbers of openings is 4openings with rectangle shape
because it reduces the scour by 54.51%. In finally to improve this scour by divergent angle lead to
the best angle is 10º can minimize the scour is 65.38%.