Study on behavior of ponding time based on characteristics of infiltration rate and rainfall intensity with varying return period

Abstract

Abstract Runoff management is based on two main concepts: controlling runoff discharge and managing concentration (Tc). Tc is closely related to understanding ponding time (tp), which is associated with estimating the length of tp on a land surface. The present study aims to investigate the behavior of tp due to varying infiltration rates (f) and rainfall intensities (i) with different return periods (Tr). The ponding time (tp) was derived from graph analysis of infiltration rate and rainfall intensity with Tr 2, 5, and 10 years. Infiltration measurements were conducted at 8 points using a double-ring infiltrometer. Meanwhile, rainfall data were obtained from 2010 to 2019. The observed tp (tpobs ) was derived through overlying between infiltration rate curve and rainfall intensity. In contrast, empirical tp (tpemp ) was estimated using Horton’s formula. The result confirms that the infiltration rate followed an exponential curve and varying rainfall intensities. Infiltration rates give vary in tp where the longer Tr, the faster the initial time of tp. There was fairly good consistency between tpobs and tpemp as shown by relatively high-value R2 >0.6) for Tr 2, 5, and 10 years. It indicates that the Horton’s formula has reliable to estimate tp in the study area.