Implications of Reference Streamflow Selection on Water Resources Management

Código

I-EBHE0183

Autores

Victor Luis Padilha, Eder Alexandre Schatz Sá, William Muller, Igor Souza Lazzari, Talita Varela Lima, Gabriel Gonçalves

Tema

WG 2.6: Water systems analysis for integrated planning & management

Resumo

In water resources management, the knowledge of water availability and water demand within a watershed is fundamental. The difference between these two parameters generates the water balance, which is crucial for identifying areas of water scarcity and improving water resources management. Water availability is susceptible to factors such as climate change, land use changes, and contamination, necessitating continuous studies to ensure sustainable water resource use. This study analyses the Lages Plateau Hydrographic Region (RH4), specifically focusing on the Canoas River and Santa Catarina tributaries of the Pelotas River watersheds, in Brazil. Through the obtained data, a quantitative water balance modeling was conducted, revealing areas with varying water availability and deficits. The evaluation of the water balance against the Q98, Q95, Q90 and Qmlt references for all the 1825 reaches associated with a geo-referenced database from the State with a cartographic base on the scale 1:10,000 was developed. Most water bodies in the Canoas River watershed were classified as "Adequate," meeting local water demands. It is clear that the more restrictive the streamflow, the less demand is met in the watersheds. In relation to the Q98, the study area presented total service in 98.11% of the reaches, whereas with the Qmlt (less restrictive) this service increases to 99.45% for both watersheds. Considering the comparison between two studied options within the flow duration curve, Q98 (more restrictive) and Q90 (less restrictive), the Canoas River watershed showed a 17.65% reduction in reaches with water availability issues, whereas the Pelotas tributaries showed an 87.5% reduction. These results highlight the importance of choosing appropriate reference streamflow for effective water management. The Pelotas watershed showed significant relevance in reference streamflow choice, unlike the Canoas watershed, with more urban areas and water demands, suggesting rural areas keep natural discharges and water storage with less interference within the water balance processes. Globally, climate change is causing significant drought-related damages and increasing weather extremes, affecting water regimes and biodiversity. Reliable water balance models require comprehensive, continuous data and advanced computational capabilities. This type of assessment is crucial for legislative discussions on water management. Continuous evaluation of water quantity and quality in specific watersheds is essential to ensure sustainable resource use. As climate variations impact water resources, selecting appropriate assessments is crucial for effective management and planning.