Desempenho de sistemas drenantes para fins agrícolas.

Abstract

The purpose of this research was to evaluate the hydraulic performance of different subsurface drainage systems under laboratory controlled conditions, using a sand tank horizontal physical model. The drainage systems were composed by the following materials: smooth PVC pipe for sewage, with nominal diameter of 50.0 mm and opened area of 23,0 cm2 ; Drenoflex corrugated flexible PVC pipe, with nominal diameter of 65,0 mm and opened area of 23,0 cm2 ; Kananet corrugated flexible polyethylene pipe of high density from the Kanaflex, with nominal diameter of 75,0 mm and opened area of 110,0 cm2 ; and the envelopes made of old tire, zero crush and pulp of sugar-cane. The factorial statistical arrangement was used, where the nine treatments with three repetitions each, involved all combinations between drainage pipe and envelope. The evaluation of the drainage systems performance was based on typical parameters proposed in the literature. Respecting to inlet hydraulic head, all drainage systems were classified as bad. Considering the ratio between the inlet and total hydraulic head, the obtained results weren't satisfactory. Regarding the entrance resistance factor, it was verified for all drainage systems very good performance. The envelope of old tire presented larger entrance resistance. Also, it was verified that the smaller values for the entrance resistance were obtained with the use of zero crush envelope, followed by the envelope in the pulp of cane-sugar. All drainage systems the larger and smaller flow were obtained with the use of zero crush and pulp of sugar-cane, respectively.