Monitoring the sediment loading of Itaipu Lake and modeling of sheet and rill erosion hazards in the watershed of the Parana River: an outline of the Project
The Itaipu hydroelectric project, the worlds largest, did not have a problem with sediment loading initially and was expected to have a life of +300 yr. Since, landuse change from forest to crops increased sediment to the lake. This change caused a reduction in quality of aquatic habitat, reduced capacity, and shortened the project life. To determine the extent of sedimentation and target areas producing sediment, a study began to monitor sediment flux, and model the watershed to determine those areas to concentrate conservation efforts. A methodology was developed which includes: 1) Monitoring major tributaries with a network of gauging stations and turbidity meters. 2). Measuring stage height and developing calibration curves relating height to discharge. 3). Measuring turbidity and calibrating to sediment load. These measurements will be digitally recorded and allow computation of water and sediment flux hourly to the lake. Modeling will use the Revised Universal Soil Loss Equation (RUSLE) in a Geographic Information System (GIS). RUSLE erosivity (R) will be collected from a network of climatic stations, erodibility maps (K) from existing data, topographic (LS) data from digital elevation models (DEM) and cropping and management (C and P) from remote sensing and field plots. These parameters will allow predicting erosion spatially in a GIS. Monitoring will be compared to predictions on smaller watersheds to calibrate the RUSLEIGIS model. The calibrated model will be used to develop erosion potential maps for the watershed. The impact of this project is a prediction of the effect that land-use change has had on the project life and areas can be targeted for conservation efforts to protect the project life.