Hydrological indicators for water resources management in the Tocantins Araguaia Hydrographic Region – RHTA

Abstract

Water is an indispensable resource for the survival of life on earth. In this sense, the analysis of water circulation in quantity and quality in river basins is fundamental for the management of water resources. In this context, the objective of the study was to evaluate the flow regime using hydrological indicators in the Tocantins Araguaia Hydrographic Region - RHTA. In this way, data from fluviometric stations were extracted from the Hydrological Information System (Hidroweb) of the National Water and Sanitation Agency (ANA), the period from 1978 to 2017 (30 years) was standardized for the quantification of hydrological indicators, namely: Long-term average specific yield; Maximum specific yield; Minimum specific yield; Specific performance with 95% permanence; Average performance with 95% retention rate; Specific yield of seven days and 10 years of return time; Natural regularization index; Minimum reference index; Average flood flow index; and Index of the upper limit of the riverine floodplain. For series with flow data (m³/s) at 28 selected stations. Therefore, the results indicate that the station (23230000) located in the middle of Tocantins in the municipality of Goiatins - TO and (19985000) located in Pacajás - PA inserted in UPH- Pará has greater water availability. On the other hand, station 26710000 in Sandolândia – TO, located in the middle of Araguaia, expressed low income. The indicator (RE95) identified that except the state of Tocantins, all other Goiás, Mato Grosso and Pará that enter the basin use 70% of the Q95%, attributed to the results corresponding to 134.25 m3s-1, which are destined for multiple uses. The indicators (Re7.10)) and (I7.10) demonstrated that the basin has a medium potential for natural regularization and a low capacity for natural regularization.