Operating yields of an aquatic weed harvester and a long-arm hydraulic excavator in aquatic macrophyte control in Piraquara II reservoir, southern Brazil

ABSTRACT Eutrophication of water bodies has caused environmental imbalance, changing population dynamics, as the excessive growth of aquatic macrophytes. The mechanical methods are the most used to control these communities. The aim of this study was to evaluate the operational yield of a harvesting boat and a long-arm hydraulic excavator (in group and individually) in the removal of floating aquatic weeds (and their Nt and Pt contents) in Piraquara II Reservoir, in Southern Brazil. The duration of each of the 100 operational cycles (including loading, transport and unloading of trucks), besides other activities were measured through timing. The hydraulic excavator presented right yields in the removal of weeds from the water body as compared to other studies reported in the literature. However, the adding of the harvesting boat led to an increase of productivity (about 115%). The average yield was 35.57 ± 0.27 m3/h or 284.67 m3/day. Applying area, mass and volume relations for the studied site, this is equivalent to 3273.7 m2/day (considering 11.5 m2/m3) or 142.28 humid tons/day (humid density of 0.5 ± 0.08; n = 30). Therefore, for similar situations, both equipment (mainly in a joint operation) are recommended to aquatic weed infestation control.