Author(s): Oscar Jimenez; Carlos Rodriguez; Nils R. Olsen
Linked Author(s): Carlos N. A. Salinas-Rodriguez, Nils Reidar B. Olsen, Óscar Jiménez
Keywords: Ngostura power plant; Reservoir sedimentation; Numerical model; Flushing
Abstract: This paper describes the sedimentological studies for the Angostura Power Plant, Costa Rica. The plant, in operation since October 2000, is located in the middle basin of the Reventazon River, and has a reservoir of about 15×10 6 m 3. The river up to the project site has a drainage area of 1,463 km 2, with large slopes and high precipitation, exceeding 6,000 mm in some areas, which results in a heavy sediment production. Since the initial planning studies, very detailed surveys were carried out to quantify the sediments entering the future reservoir. This information helped to design a strategy for handling and routing the sediments including operational procedures, definition of suitable bottom outlets, definition of flushing procedures and appropriate monitoring of the reservoir. One of the most important topics of these studies was the computation of the sediment deposition pattern along the reservoir, which has a very complex geometry. For this, several procedures were employed, from empirical methods to a fully 3D hydrodynamic model able to compute the flow and suspended sediment fields. These computations were carried out back in 1994 and at that time several shortcomings of the computation were evident. Currently, with the development of wetting/drying algorithms, the use of unstructured grids, and more efficient numerical techniques, many of these problems have been overcome. Nevertheless, the results were useful in planning the future operation of the reservoir. Prototype measurements for the first years of operation are reported.
Year: 2004