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Hydrology and Earth System Sciences An interactive open-access journal of the European Geosciences Union
doi:10.5194/hessd-12-9915-2015
© Author(s) 2015. This work is distributed
under the Creative Commons Attribution 3.0 License.
Research article
25 Sep 2015
Review status
This discussion paper has been under review for the journal Hydrology and Earth System Sciences (HESS). The manuscript was not accepted for further review after discussion.
Identifying hydrological responses of micro-catchments under contrasting land use in the Brazilian Cerrado
R. L. B. Nobrega1, A. C. Guzha2, G. N. Torres3, K. Kovacs1, G. Lamparter1, R. S. S. Amorim3, E. Couto3, and G. Gerold1 1Faculty of Geosciences and Geography, University of Göttingen, Göttingen, Germany
2Center for International Forestry Research (CIFOR), Nairobi, Kenya
3Department of Soil Science, Federal University of Mato Grosso, Cuiabá, MT 78060-900, Brazil
Abstract. In recent decades, the Brazilian Cerrado biome has been affected by intense land-use change, particularly the conversion of natural forest to agricultural land. Understanding the environmental impacts of this land-use change on landscape hydrological dynamics is one of the main challenges in the Amazon agricultural frontier, where part of the Brazilian Cerrado biome is located and where most of the deforestation has occurred. This study uses empirical data from field measurements to characterize controls on hydrological processes from three first-order micro-catchments < 1 km2 in the Cerrado biome. These micro-catchments were selected on the basis of predominant land use including native cerrado vegetation, pasture grass with cattle ranching, and cash crop land. We continuously monitored precipitation, streamflow, soil moisture, and meteorological variables from October 2012 to September 2014. Additionally, we determined the physical and hydraulic properties of the soils, and conducted topographic surveys. We used these data to quantify the water balance components of the study catchments and to relate these water fluxes to land use, catchment physiographic parameters, and soil hydrophysical properties. The results of this study show that runoff coefficients were 0.27, 0.40, and 0.16 for the cerrado, pasture, and cropland catchments, respectively. Baseflow is shown to play a significant role in streamflow generation in the three study catchments, with baseflow index values of more than 0.95. The results also show that evapotranspiration was highest in the cerrado (986 mm yr−1) compared to the cropland (828 mm yr−1) and the pasture (532 mm yr−1). However, discharges in the cropland catchment were unexpectedly lower than that of the cerrado catchment. The normalized discharge was 55 % higher and 57 % lower in the pasture and cropland catchments, respectively, compared with the cerrado catchment. We attribute this finding to the differences in soil type and topographic characteristics, and low-till farming techniques in the cropland catchment, additionally to the buffering effect of the gallery forests in these catchments. Although the results of this study provide a useful assessment of catchment rainfall–runoff controls in the Brazilian Cerrado landscape, further research is required to include quantification of the influence of the gallery forests on both hydrological and hydrochemical fluxes, which are important for watershed management and ecosystem services provisioning.

Citation: Nobrega, R. L. B., Guzha, A. C., Torres, G. N., Kovacs, K., Lamparter, G., Amorim, R. S. S., Couto, E., and Gerold, G.: Identifying hydrological responses of micro-catchments under contrasting land use in the Brazilian Cerrado, Hydrol. Earth Syst. Sci. Discuss., 12, 9915-9975, doi:10.5194/hessd-12-9915-2015, 2015.
R. L. B. Nobrega et al.
R. L. B. Nobrega et al.

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Short summary
This study examines the rainfall-runoff processes in micro-catchments in which a main source of variability is the contrasting land use. The study area is located in the Amazonian agricultural frontier, in the Brazilian Cerrado biome, and it aims to fill a gap in the literature concerning the Brazilian Cerrado, and to understand how streamflow and catchment hydrologic regimes are conditioned by microclimate, precipitation pattern, land cover and soil properties, among other catchment properties.
This study examines the rainfall-runoff processes in micro-catchments in which a main source of...
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