Evaluation of collective water rights allocation scenarios using the WEAP simulation model in a region of water use conflicts: the case of Formoso River Basin – Tocantins state/Brazil

Abstract

The aim of the present study was to carry out a hydrological simulation of the Formoso River basin using WEAP and to model scenarios based on the rotating rules of the water pump in regions of conflict for the use of water. During July 2020, the influence of such rules on the remaining flow in these regions was assessed considering a collective grant context in which minimum environmental flows, determined from the seasonal Q90 (flexible) and monthly Q95 (conservative), should be preserved downstream from the critical sections. The results showed that the remaining flow exceeded the limit of the flexible environmental flow in 61% of the days in the middle stretch of the Formoso River and at the mouth of the Urubu River. In the lower section and mouth of the Formoso River, these values were above the conservative limit in 93% and 100% of the days, respectively. It was concluded that the application of the rules, coupled with the collective grant, could produce satisfactory results for water availability in the basin.