using developed building block method in estimating of environmental flow (case study: gumbar river )

abstract given the importance of environmental cycles had led to allocation of water-right for water species and ecosystems which is known as environmental flow or in stream flow. from among the various methods for estimating environmental flow, building block approach is considered as a very powerful tool for estimating the water needs. in this paper, beside simplifying the building block approach and with regard to water flow properties of gamber river in west azerbaijan province, we attempt to revise and localize this method. the results revealed that in this method, unlike the previous ones, instead of considering a constant index for environmental flows, we can quantify environmentally daily and monthly time series. in so-called method, environmental flows in various management classes were closer to tnant normal values and in classes of a, b, and c, they were higher than environmental flows in more wetted perimeter method.