Qualitative analysis between increased demand for wells and changes in activities at the community scale, case study of the Forquilha and Algodão Creek, Banabuiú Basin – Ceará State

Climate change has modified global and local water cycle patterns inducing more intense and severe drought events. In the Ceará state (Northeast Brazil), a semiarid region very vulnerable to droughts, groundwater acts as a strategic reserve to ensure water security for small rural communities. Well drilling jointly with the building of dams and cisterns are the main policy performed by the public authority to cope with the droughts. This study performed a preliminary qualitative analysis to investigate the anthropogenic effect of the recent drought (2012-2016) in the local hydrogeological environment. The study area selected was the micro-basins of the Algodão and Forquilha creek, in which the alluvial aquifer has been monitored by Funceme since 2010. This aquifer has a great importance for local agricultural development and the water supply for domestic activities. A historical analysis of the evolution of well drilling was performed. In the physical context, the piezometric level of the wells monitored were evaluated. The well drilling was notably more intense between the years 2015 and 2018 and a continuous drawdown of the groundwater level was observed in response to the last drought event. Since 2017 the piezometric level started to rise, however, the monitoring reveals a different pattern of the piezometric levels after the latest drought, with sudden changes between the periods of recharge and drawdown of the aquifer. In the social context, field diagnostics with local stakeholders revealed how the wells installation changed the dynamics of the activities developed by the rural communities. Observed effects were the increase of the number of families and the development of local economics. The heterogeneity of this environment and of its water users requires efficient management policies adapted for the local physical and socioeconomic conditions to avoid overexploitation and maintain the recharge of the aquifers.