Comparative analysis of runoff in experimental catchment in semiarid tropical climate

Abstract

This study was carried out to evaluate the hydrological relationship of two catchments with similar
characteristics, as well as to quantify the effect of the vegetation management to generate runoff at micro-scale.
This study was conducted in two experimental catchments, one covered with native vegetation and other with
thinned vegetation, with areas of 2.06 and 1.15 ha, respectively, located at Iguatu municipality, Ceará, Brazil.
This study was carried out during the rainfall seasons in the years 2009, 2010, 2011 and 2012, in a total of
198 rainfall events. In native watershed 75 runoff events were registered, while in thinned one 62 runoff events
occurred. Results showed that the thinned vegetation promoted the reduction in the runoff, with a effective
precipitation of 9.0% for the catchment cover with native vegetation and 5.6% for the catchment with thinned
vegetation. The influence of the land cover was also observed at the peak discharge. The thinned vegetation
showed a peak discharge equal to 3.73 L s^-1 ha^-1 while the native vegetation showed a peak discharge equal to 4.42 L
s^-1 ha^-1 with a difference around 15.6%. The rise groundcover due to the thinning of vegetation led to a reduction of
runoff and decrease the peak flows. Results point out that thinned vegetation is a adequate management practice
for production pasture and water retention capacity of soil wich promotes the conservation of natural resources.