Assessment of Environmental Flow Under Historical and Climate Change Scenarios in a Tropical Basin in Mexico

ABSTRACT Environmental flow is a way to analyze the ecological condition and the requirements of biodiversity to maintain a healthy state in terms of water flow quantity, quality, and timing required by ecosystems. Analyzing environmental flows can help to understand the hydrological and ecological impacts that occur in a given river or basin. Combined with climate change scenarios, these impacts may intensify, potentially altering watercourse regimes, the health of aquatic ecosystems, and the condition of natural habitats. The objective of this research was to evaluate the environmental flow through historical and projected climate change information presented in the Santa Cruz de Aquismón subbasin, SLP, Mexico. The historical environmental flow was analyzed for a period spanning from 1954 to 2014, while the projected climate change information used was the CNRM‐CM5 model and the 4.5 and 8.5 Representative Concentration Pathways (RCP) for a medium term (2045–2069). Historical results indicate that over time, the flow increases in the rainy season, while in the climate change scenario, there is a decrease in magnitude but greater variability in the flow. This research shows the need for assessments that integrate the temporal evolution of environmental flows because, over time, the variability and magnitude of the regimes change without depending on the presence or absence of any type of infrastructure. In addition, this research can be replicated in different streams because it does not use a specific methodology for a single type of watercourse or basin.