Limnological characterization of the Itumbiara hydroelectric reservoir, Goiás, Brazil

  • Renata Fernandes Figueira Nascimento Instituto Nacional de Pesquisas Espaciais
  • Enner Alcântara Instituto Nacional de Pesquisas Espaciais
  • Milton Kampel Instituto Nacional de Pesquisas Espaciais
  • José Luiz Stech Instituto Nacional de Pesquisas Espaciais
Keywords: limnology, bio-optics, reflectance, case 2 waters

Abstract

The main objective of this work was to characterize the water properties of the Itumbaira, GO, hydroelectrically reservoir based on limnological and radiometric parameters. Two field campaigns were organized, the first during rainy (May) and the second in the wet season (September). In these field campaigns, the following limnological parameters were analyzed: chlorophyll-a, dissolved organic and inorganic carbon, total suspended matter, water temperature, pH and turbidity. The radiometric data were taken using a FieldSpec Hand Held portable spectroradiometer. Also the absorption coefficient of the optically active components (OAC) of the water were measured in laboratory. The limnological data was interpolated using Ordinary Kriging algorithm and the radiometric data were transformed in remote sensing reflectance. The absorption coefficient was used to build a triangular diagram designed to verify the relative contribution of the OAC in water. The results show that there was a distinct spatial variation in the limnology of the area affected by the dam and the one under the river confluences. Due to the low chlorophyll-a concentration in water, the spectral response was strongly influenced by inorganic suspended particles. The triangulation of the absorption coefficient revealed that the water is dominated by the inorganic particulate matter (from 65 to 80%). These results set the Itumbiara's water as case 2 water.

Author Biographies

Renata Fernandes Figueira Nascimento, Instituto Nacional de Pesquisas Espaciais
Divisão de Sensoriamento Remoto
Enner Alcântara, Instituto Nacional de Pesquisas Espaciais
Divisão de Sensoriamento Remoto
Milton Kampel, Instituto Nacional de Pesquisas Espaciais
Divisão de Sensoriamento Remoto
José Luiz Stech, Instituto Nacional de Pesquisas Espaciais
Divisão de Sensoriamento Remoto
Published
22/08/2011
Section
Papers