Water Supply Reservoir Operation in Relation to Climate Variability: Pirapama River Basin (Pernambuco-Brazil)

Abstract

The vulnearability of water resources systems is highly influenced by the climate variability of the region. The effects are amplified when the region has high population density and important economic activities such as the Recife Metropolitan Region (RMR), whose population is 3.8 million inhabitants, corresponding to 51% of the urban population in Pernambuco State. The Pirapama reservoir was designed to produce 5.6 m3/s, which corresponds to 37% of the total water demand of the RMR. The objective of the paper is to define strategies for the Pirapama reservoir operation by using guide curves and taking into account the climate variability, particularly drought events, to minimize or even avoid the conditions of rationing and collapse of its storage. The rainfall-runoff model SMAP was used to simulate input streamflow in the period 1933-2014 and the water allocation model Acquanet was used to simulate the operation rules proposed. The guide curves were defined based on the Standard Runoff Index, which classify the input inflow in drought categories. For each drought category, a response goal was defined for withdrawal reduction. This strategy may be an efficient tool to deal with the climate variability present in Northeast Brazil, which can be amplified with the effects of the climate change. In this sense, the development of sustainable operation rules can be considered an adaptation measure for reducing the impacts of possible climate changes in the future.