Mahboobeh Hajiesmaeili - MScstudent, Department of Water StructuresEngineering, Tarbiat Modares University
Seyed Ayyoubzadeh - Associate Professor, Department of Water StructuresEngineering, Tarbiat Modares University
Mehdi Sedighkia - Ph.Dstudent, Department of Water StructuresEngineering, Tarbiat Modares University

Increase in water demand has caused that researches related to instream flow needs(IFN)assessment developed rapidly in recent years. Using the physical habitat assessment as a powerful tool in management of river ecosystem has not become a common method in many countries, yet. The main aim of the present research is representing the abilityof habitatsimulation technique in river ecosystemmanagement. Delichai stream in Tehran province in Iran is selected as the case study. Based on the results habitat simulation technique has considerable ability for dynamic assessment of IFN and river habitat evaluation along the longitudinal and latitudinal cross sections and it can also present the spatial habitat suitability distribution in various months of the year dynamically. IFN assessment with habitat simulation technique has advantages related toother methods like that of the Tennant method and wetted perimeter method and creates the least discussion between river environmental managers and stakeholders. In the study stream of this research due to the variation of ecological condition for the target species, three different values for IFN in various months of the year wereestimated and it was seen that the habitat near the stream bank requires more protection and restoration projects.

Instream Flow Needs, River Ecosystem, Habitat Simulation, Delichai stream, Physical habitat