Analysis of Phreatic Levels in Riparian Forest and Pasture in an Agricultural Watershed, Santa Catarina, Brazil

Abstract

This study analysed the short-term behaviour of groundwater levels under two different conditions, riparian forests and pasture, in Concordia watershed, Lontras, SC, Southern Brazil. Data referring to 3 piezometers were used. PZMC is installed in a riparian forest and PZ2127 and PZ3 in pasture areas. PZ2127 is located near the watershed's outlet. Water levels of the river outlet installed near PZ2127 were also used. Storm events were selected considering the historical record, from 23 April 2012 to 2 September 2015. Water levels that exceeded 60% of the maximum amplitude recorded in all piezometers were the criteria for the storm event selection. Ascension and recession coefficients were calculated for the entire duration of each event, for phreatic levels and water levels, at 2 h intervals. The difference between water and phreatic levels peaks was calculated. Decay of the mean coefficients of ascension and recession can be observed as consequence of the increase of distance and depth. Ascension movements are faster than recession movements for piezometers and water level. This result is important to develop the knowledge about local hydrological processes that involves phreatic aquifers, in view of watershed management.