Banca de DEFESA: RUAN RICARDO SILVA DE JESUS

ASSESSMENT OF SURFACE WATER AVAILABILITY IN THE BASIN URARICOERA RIVER HYDROGRAPHIC, RORAIMA

Water balance. Hydrological behavior. Water resources. Hydrometeorological situation.

The Uraricoera River Basin, located in northwestern Roraima, Brazil, is a region of great water importance, but still little explored in terms of detailed studies on the availability and management of its water resources. Based on this perspective, the present study aimed to evaluate the surface water availability in the basin, addressing specific aspects such as precipitation analysis, definition of the hydrological year, estimation of minimum reference flows (Q7.10, Q95, and Q90) and assessment of the balance between water demand and availability. The methodology involved the collection and analysis of hydrometeorological data from rainfall and fluviometric stations, the application of statistical and geoprocessing methods to fill gaps in the data, and the use of probability distribution models to estimate reference flows. The results indicated that the highest rainfall in the basin occurs in the upstream areas, and the rainfall regime showed significant seasonal variation, with the rainy season concentrated between April and August. The concentration of intakes near the mouth suggests an imbalance in the allocation of grants, highlighting the need for more balanced management. In addition, the analysis of the minimum reference flows showed that the Q90 flow presented the highest water availability, with a Water Commitment Index (ICH) below 50%, indicating availability conditions. In contrast, the adoption of 50% of Q7.10 revealed a scenario of unavailability, with an ICH above 100%, highlighting the management challenges during periods of drought or high demand. As a final product, this study resulted in the preparation of the technical note “Hydrome-theorological Situation and Water Availability of the Uraricoera/RR River Basin”, a practical tool that consolidates these findings and offers support for the efficient and sustainable management of the basin's water resources.