Hydrologic response to climate change in arid regions: Case study in los Comondú, Baja California Sur, Mexico

Abstract

Background. Currently, climate change is one of the most relevant phenomena within the scientific environment; this change has been recorded as an increase in temperatures on a global scale. For the central zone of Baja California Sur (BCS), Mexico, climate models also indicate an increase in the frequency of extreme precipitation. The study area covers two towns (San José and San Miguel de Comondú) whose urban and rural areas are located in a ravine of approximately 16 km in length and up to 800 m in width. Goals. To carry out a historical, statistical analysis of the climatic variability and model the response of the Comondú stream to extreme precipitation events. Methods. Climatic variability was analyzed with databases from the Comondú weather station, operated by the National Meteorological Service (SMN). In addition, the runoff pattern in the Comondú stream was ascertained in the event of extreme precipitation events, similar to or close to events with a return time of 1000 years, using hydrological and hydraulic models of HEC-1 and HEC-RAS software. Results. In the case of Los Comondú, BCS, there is a clear upward trend in the 24-hour extreme precipitation data, which implies that the danger of flooding in populated areas and crops increases considerably. The occurrence of a 1000-year event would affect about 86,864 m2 of the urban area of both towns and 201,570 m2 of the area under cultivation. Conclusions. The results of our modeling indicate an increase in area, depth, and speed of the stream, increasing the risk of flooding in the lower areas of Los Comondú, BCS. Based on our modelings results, measures should be promoted to safeguard the population and the economy of Los Comondú.