Field observations and modeling of mountain stream response to control dams in Venezuela

摘要

In February 2005, intensive rainfall took place along the Avila Mountain in the Vargas State, Venezuela, over the same area affected by the 1999 catastrophic debris flows. Flash floods and small scale debris flows were generated again in some of the streams, causing flooding of water and sediment in the urban areas. The damage was minimized due to sediment control dams that were built after the 1999 event. This paper describes the main characteristics of the February 2005 floods and the effects on the sediment control dams built in Vargas State. A mathematical model, developed for simulation of flow and sediment transport in mountain streams, is applied to reproduce the deposition patterns and grain size distribution changes upstream of sediment control dams. A hypothetical case is presented to show the applicability of the model. The paper also illustrates the process of sedimentation at some of the dams and the attempts to use the numerical model to reproduce the observed data.