Simulation of structural and non-structural measures for climate change adaptation in water resources systems in the Capibaribe and Ipojuca River basins, Pernambuco state, Brazil

ABSTRACT This paper evaluated the structural and non-structural mitigation measures in the Capibaribe and Ipojuca River basins in the state of Pernambuco, Brazil, listing the best measures to deal with climate change and ensure water security in areas that already suffer from water scarcity. For this, five global circulation models were used, after bias correction, as input data for the self-calibrated hydrological model (MODHAC). Subsequently, 10 water allocation scenarios were simulated, using historical data and future scenarios (2051–2080) to meet the water demand for human and industrial supply, water for livestock and other farm animals, irrigation, and energy in the studied river basins. The allocation scenarios involve the implementation of structural and non-structural measures either in isolation or in combination. Among all solutions, the transfer of water from the São Francisco River offers the most significant increase in supply, but it requires the largest investments. Thus, public agencies should consider "soft path" (non-structural) measures more closely, as they require fewer financial resources and can yield satisfactory results in various scenarios. However, in some scenarios, these measures are not sufficient to meet all demands, and other solutions must be considered.