Hydrodynamic modeling and morphological analysis of lake Bolonha: a water source in Belém, Pará State, Brazil

Current paper's main contribution includes hydrodynamic modeling and morphological analysis of lake Bolonha which, along with lake Agua Preta, makes up the Utinga watershed in Belem, Para State, Brazil. Bathymetry of lake Bolonha was undertaken by digitalizing the data provided by COSANPA (the local Sanitation and Water Supply Company) dating back to 1983, and from a 2007 field study. Both bathymetries produced two terrain elevation models which were used for morphological analysis and hydrodynamic simulations. The morphological analysis showed that between 1983 and 2007, no significant relief changes occurred on the bottom of lake Bolonha, except for the formation of the outflow channels between the interconnecting channel and Bolonha Water Treatment Plant (WTP). The hydrodynamic model was able to simulate depths and velocities. The velocities, ranging between 1.8 and 9.0 cm s -1 , showed a subtle current between the outlet of the canal connecting the lakes Bolonha and Agua Preta and the water intakes of the Bolonha and Sao Braz WTPs. This fact demonstrated that lake Bolonha reservoir is a passage for waters from lake Agua Preta.