Simulation of physical habitat in Ayuquila-Armeria river inthe west of Mexico

In Mexico, until 2012 was published a norm for the determination of the ecological flow in rivers and streams, which have been severely degraded by water diversion for agricultural and industrial activities. This standard considers the simulation of the physical habitat as a measure for the determination of the flow within the Instream Flow Incremental Methodology (IFIM). In this study, simulations of physical habitat were generated, combined with fish fitness curves. To generate the habitat simulations, a section of river with 706 meters was selected, where the parameters of depth, speed and type of substrate were measured. The iRIC 1.5 software was used to calibrate and simulate the flows with the physical habitat, where the main information input was a topographic survey of the river, and the construction of the suitability curves for the selected fish species. As a result, simula-tions were obtained at different flow rates and different Weighted Usable Area (WUA) for each of the species of interest. The results showed us that when the flow falls at lower flow rates lower than 1 (m3 s-1) and higher than 200 (m3 s-1), it shows a very poor WUA decay for the four species. Few studies in Latin America have been developed for this type of analysis, so this study contributes significantly as a methodological process that will help improve the research of environmental flow in rivers.