HYDROLOGICAL RESPONSES OF A WATERSHED TO VEGETATION CHANGES IN A TROPICAL SEMIARID REGION

Authors

  • Eunice Maia de Andrade Department of Agricultural Engineering, Universidade Federal do Ceará, Fortaleza, CE
  • Rafael do Nascimento Rodrigues Department of Agricultural Engineering, Universidade Federal do Ceará, Fortaleza, CE
  • Helba Araújo de Queiroz Palácio Department of Education, Instituto Federal do Ceará, Iguatu, CE
  • José Bandeira Brasil Department of Agricultural Engineering, Universidade Federal do Ceará, Fortaleza, CE
  • Jacques Carvalho Ribeiro Filho Department of Environmental and Technological Sciences, Universidade Federal Rural do Semi-Árido, Mossoró, RN

DOI:

https://doi.org/10.1590/1983-21252018v31n119rc

Keywords:

Runoff. Thinning. Rainfall depths.

Abstract

The objective of this work was to assess the effect of vegetation on the runoff coefficients of a Caatinga dry tropical forest before and after thinning. Thus, an experiment was conducted with evaluations in three hydrological years (2008, 2011 and 2013) in Iguatu, State of Ceará, Brazil. In 2008, the vegetation consisted of a 30-year regenerating Caatinga forest. The vegetation was subjected to thinning in 2009, 2011 and 2013, removing trees with less than 10-cm diameter at breast height. Hydrological responses were evaluated as a function of daily precipitation water depths, based on cumulative frequency distribution, by dividing precipitation events into three classes (CP) (CP≤30, 3050 mm). Significant differences between runoff coefficients before and after vegetation thinning were assessed through the Student's t-test (p<0.01). Before thinning (2008), CP≤30 mm showed the highest runoff coefficient, differing statistically (p<0.01) from the other years. The results of precipitation events of great magnitude (CP>50 mm) indicate that the runoff is greatly dependent on rainfall characteristics and soil moisture conditions. The greater development of herbaceous vegetation due to thinning reduced the surface runoff.

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Published

11-12-2017

Issue

Section

Agricultural Engineering