Field study along one of the upper reaches of Ammameh in Jujrud river basin showing a series of particular

hydraulic and morphological specifications. The selected study reach is 145 meters long and has

step-pool morphology based on Montgomery and Buffington's classification.

Investigations show that steps through the reach affect the flow pattern. In other words, 40 through nearly

80 percent of reach friction factor are due to steps and knick zone in low to high flow spectrum. This

reason induce sub-critical regime for water profile in spite of steep slope (at least 10%). On the other hand,

there is distinct flexibility of river morphology due to recent hydraulic circumstance. Field operations and

data analyzing reflect that if the length between two successive steps is long, the pliability of alignment

made deeper. The pool configuration downstream of step is trapezoidal shape for energy dissipating and

having submerged hydraulic jump.