The connectivity of the Paranapanema River with two lateral lakes in its mouth zone into the Jurumirim Reservoir

HENRY¹, R.

¹ Departamento de Zoologia, Instituto de Biociências, UNESP, CP: 510 CEP18618-000 Botucatu-SP, Brazil. e-mail: rhenry@ibb.unesp.br

ABSTRACT: The pattern of hydrological interactions of the Paranapanema River with two lateral lakes in its mouth zone into the Jurumirim Reservoir was examined during a four-year period (from January 1, 1998 to December 31, 2001). Measurements of water level and precipitation were obtained. The volume and surface area variability of the two lateral lakes was described for the study period. Except during a prolonged period of drought (from October 1999 to December 2000), the lakes were connected with the Paranapanema River, and the annual range of water level was around 2.4-3.0m. The variability of the lateral hydrologic pulse produced highest variation in surface area than volume in the two lakes (except during the drought period). However, the area elasticity coefficient of one of the lakes (Camargo Lake) was around 50% smaller than the other (Coqueiral Lake). The volume elasticity coefficient of the Camargo Lake was around five times smaller than of the Coqueiral Lake. The differences on elasticity coefficients were attributed to the morphometry of the lakes. Except during the drought, the lateral environments are maintained permanently in a potamophase. This type of behavior is not a characteristic of a floodplain. Thus, the stored water in the Jurumirim Reservoir acts as a buffer system of hydrological pulses, in the riverine zone of reservoir.