Análise da eficiência de sistemas de acumulação de água de chuva considerando a variabilidade dos regimes pluviais no Rio Grande do Norte e cenários de aporte hídrico externo

Abstract

The semi-arid regions are subjected to water scarcity over much of their territory. Therefore, it becomes necessary to use rainwater harvesting alternatives to achieve a balance between water demands and supply. Rainwater Harvesting Systems (RHS) have been widely adopted in various regions worldwide with the potential to increase water supply capacity. This study is based on the concept of variability in rainfall distribution in homogeneous zones to analyze the effect of precipitation on the efficiency of RHS in the State of Rio Grande do Norte, considering two variables in the rainfall regime: precipitation and PCD index (Precipitation Concentration Degree), which represents the degree to which the total annual precipitation is distributed throughout the year. Thus, this study aimed to analyze the efficiency of RHS for different combinations of demand, catchment area, and reservoir volume, considering different rainfall regimes. Additionally, the effect of external water supply by tanker trucks was analyzed. In the first analysis, the only water supply considered was from precipitation; then, scenarios of cistern supply possibilities using tanker trucks were considered. In the first analysis, a more relevant increase in efficiency was observed with an increase in the catchment area. The analysis of water supply with tanker trucks demonstrated that, for the scenarios considered, the catchment area is the main factor related to the need for tanker truck supply. The results obtained revealed that the catchment area is the main variable associated with RHS efficiency and that the rainfall regime influences the system's efficiency, meaning that the higher the precipitation and the lower the PCD index, the rains will have a greater volume and will be more evenly distributed throughout the year.