Mankind has used water in different ways (agriculture, urban consumption, industrial activities, etc), making it an engine of economic development of nations, but ignoring the value of the ecosystems that sustain the aquatic environment. Environmentalflows are part of a sustainable water system management focused on maintaining a good ecological status. The purpose of this work was todevelop and implement a methodology for determining the environmental flow regime (RQA) in the middle of the river basin Tulua, as a pilot basin in the determination of RQA in Colombia. This informationwas collected hydrological, hydraulic, water quality and water intake and referrals, we used the HEC RAS model, in this case to simulatethe hydraulic behavior of the surface current to later verify the information with a model or information associated with ecological and environmental aspects of the proposed RQA and verify the conditionsof habitability, and to assess the RQA with consumptive uses of the basin. The methodology was consistent for the section studied, showing a variable RQA and convenient throughout the year, with living conditions imposed
