Implications of the New Operational Rules for Cantareira Water System: Re-Reading the 2014-2016 Water Crisis

Abstract

During the 2014-2016 water shortage crisis, the Metropolitan Area of Sao Paulo (MASP) water supply system extracted pumping volume from the Cantareira System. Before the crisis, between 1984 and 2013, the reservoir’s average water extraction flow was 29.6 m3·s-1. During the period of pumping volume usage, the average extraction flow was 16.2 m3·s-1. Following the crisis, two new mitigation policies were implemented: a water extraction Resolution (in 2017) and a Resolution for water reallocation from another basin (in 2018). This study provides a novel investigation of the Cantareira System water crisis by assessing the mitigation policies impacts on storage level dynamics. The system storage level was evaluated using the reservoir simulation module of PDM-Cemaden hydrological model, assuming that the new policies had already been implemented prior to the crisis. A control simulation was run with observed in- and out-flow and operationally-practiced extraction flow. The storage level dynamics impacts were evaluated under 4 water mitigation policies scenarios varying the policies implementation starting date, the extraction flow range and including the water reallocation variable. Results showed that pumping volume would only need extraction during a short period (Scenarios I, III and IV), and considering the water reallocation, pumping volume extraction would not have been necessary (Scenario II). Although the pumping volume would still have been extracted during a short period, water shortage impact would have been lessened, had the policies been already implemented before the crisis. The water mitigation policies implementation supports the reservoirs storage management but does not guarantee that MASP water demand is fully met. Therefore, in order to effectively improve water security, further policies and practices to reduce water demand and enhance supply should be considered.