As a cansequence of Marun dam construction on the Jarrahi River, qualitative and quantitative changes

of inflow is an ecological threat on wetland ecosystem. In order to prevent the long- term negative impact

of the projects on the ecosystem, it is necessary to assess the environmental flow and optimum water allocation

for different uses. In this research, environmental flow indices were investigated using hydrological

analysis of wetland inflow at Jarrahi River. Environmental flow estimated in Shadegan wetland are 6.83,

1.54 and 3.18 m

on Montana method, environmental flow is estimated 1.54 and 3.6 m

respectively. The results have shown that environmental flow indices were decreased after dam construction

in all hydrometric stations.