The estimate of maximum rainfall intensity is of great concern in agricultural projects such as the use of terraces for erosion control, dams, and soil water drainage. Rainfalls can be characterized by their intensity (mm h-1), duration time (min), and return period (years). One of the analyzed models has been used for estimating the maximum rainfall intensity to be applied in dimensioning such agricultural structures, for a given return period and storm duration. The time of concentration in small watersheds, frequently between 60 and 120 min, has been used as duration of storm in the estimate of intense rainfalls. For such a duration time, there are other models that can better estimate, and, consequently, be more reliable than the basic model. Thus, this work analyzed two other models used for estimating intense rainfall: an exponential and a linear model, and both were compared to the basic model. Data of annual-daily-maximum rainfall for Lavras, Minas Gerais - Brazil, from 1914 to 1991, were used to derive the models. The data were transformed into rainfall intensities, for recurrence periods varying from 2 to 100 years, and duration times between 5 to 1,440 min. The proposed exponential model provided a better estimation of intense rainfalls, with lower errors, for duration times varying from 5 to 240 min. Therefore, it can be recommended for application in watershed projects, whose time of concentration is included in this time interval. The basic model showed to be more applicable for duration times greater than 240 min, while the linear model did not provide reliable estimate of intense rainfalls for Lavras.
precipitation; hydrology; soil conservation