Determinação do Tempo de Concentração em uma microbacia hidrográfica utilizando traçador salino: estudo de caso da bacia hidrográfica do Igarapé Sapucajuba

Abstract

To determine the time of concentration (tc) of watershed, several practical methods have been developed, which are mostly empirical. However, determining this response time is difficult as these methods are often used indiscriminately through their incorrect application to their validity field. Thus, the present work aimed to determine the time of concentration for the watershed of stream Sapucajuba, from field measurements, with the aid of saline tracer (sodium chloride - NaCl) and by testing 08 empirical methods, which select morphometric characteristics of the watershed, being subsequently compared to the value measured in the field to verify which methods would be more suitable to be applied in the basin. To determine tc in the field, initial tests were carried out to determine some parameters such as test time, instantaneous measurement interval and concentration of the tracer solution. In general, the underestimated methods or the value of the time of concentration, overestimated, thus, a leakage of the water body, being the most suitable methods for tc estimates, those of Come the Chow, DNOS and Kirpich, because it found percentage errors of 9.51, 12.13 and 19.92%, respectively, compared to the time of concentration measured in the field.