Estimated soil use impacts in the Araranguá river basin through the use of the hydrologic modeling technique

Abstract

The objective of this research was to apply the hydrological model SWAT under different soil use scenarios to evaluate water availability through space and time in the Araranguá watershed. The scenarios evaluated were: I) Current soil use, that is, mostly rice cultivation in paddy fields; II) Agriculture land replacement by forestry; and III) Agricultural land replacement by bare soil. The results obtained indicate that SWAT was efficient in modeling water distribution in the Araranguá basin. Moreover, it was verified that the average daily flow of water in the Araranguá
basin occurred in the bare soil scenario. These results are supported by the reduced water infiltration and increased runoff verified in this scenario. Nevertheless, the bare soil scenario presented the highest number of days in which the estimated daily water flow (Qsim) of the basin was below the actual minimum flow through 95% of the time (Q95). The forestry scenario, in its turn, presented the lowest occurrence of Qsim < Q95 events, suggesting it may support a more stabilized water flow in the Araranguá basin throughout the year.