Estimating the water balance of a small reservoir in the Brazilian semiarid

Abstract

Small communities in semi-arid regions usually suffer from a lack of data to enable effective water management. This is the case for many rural communities in Brazil that rely on small reservoirs. The aim of this study is to extract information on water storage and water flows of Lagoa Cercada, a small reservoir in the Brazilian semi-arid region. Monthly data series of water levels and water quality were combined with remote sensing information to evaluate water storage in the reservoir. Inflow, withdrawal, and infiltration were calculated using water and salinity balance in the reservoir. The calculated capacity of Lagoa Cercada reservoir was 1.14 million cubic meters. However, using satellite imagery instead of drone imagery resulted in a 51 % difference in the estimation of storage capacity. Additionally, Lagoa Cercada's water withdrawal has not returned to the same amount as before the drought.