Comportamento hídrico na bacia hidrográfica do ribeirão João Leite, GO
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2009-02-18
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Universidade Federal de Goiás
Resumo
The hydrological behavior of watersheds derives mainly from the processes of
climate variability and land use, and thus, may be affected by human action. The João
Leite river is the main source of water supply of Goiânia, in addition to providing water to
multiple uses throughout the basin. In the last decades, this catchment have been pass for
intensive changes in land use, and recently, with the increasing pressure on water
resources, conflicts because the relative scarcity of water quantity and quality, have been
reported among users. In this context, this study aimed to analyze the trend of hydrological
variables between 1975 and 2005; to test the semivariograma model spherical, exponential
and Gaussian, adjusted by the method of weighted least squares in the mapping by kriging
of monthly and annual average precipitation; classify the land use between 1979 and 2005,
establishing the qualitative and quantitative association of the flow rate with the land use
and climate variability and finally, assess the available water produced by the combination
of different flow rates of reference and criteria for award. For this, we used satellite images
from the years of 1979, 1989, 1997 and 2005, data flow from the Captação João Leite
gauging station and rainfall from 14 stations, provided by National Water Agency of
Brazil. It was found a good performance of geostatistics techniques to map the average
monthly and annual precipitation, with emphasis on exponential model that show the best
fit. The land use was marked by 17.8% of the deforestation, expansion of the urbanization
and agriculture at 6.6 and 15.2% respectively, and expressive area of grassland, about 40%
over of time. The declining trend observed in the flow can be explained, in part, by the
reduction of the rain rate, however, due to the significant increase in stream water collected
at João Leite river and lack of historical records, there was difficulty in the qualitative
association between flow rate and land use, however, quantitative analysis models show
coefficients of determination (R ²) above 0.75. It was noted that the establishment of a
single value for the flow of reference, regardless in irrational use of water. The adoption of
the monthly reference flow show highly promising alternative to optimize the use of
surface water resources in the João Leite watershed, and consequently, to the Goiás state,
providing 40% more water than that provided by the criterion of single value.
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Citação
SANTOS, Eduardo Henrique Mendes dos. Hydrological behavior in the João Leite watershed, GO. 2009. 98 f. Tese (Doutorado em Ciências Agrárias) - Universidade Federal de Goiás, Goiânia, 2009.