TIN Model of Water Reservoir Bottom and Assessment of Model Accuracy

Abstract

Natural and anthropogenic processes are causing changes in topography of water reservoir bed. These changes are connected to the income and outcome of the sediment to the water reservoir, so the water depth and total reservoir volume changes too. Knowledge of topography of the water reservoir bed and its changes can be useful for calculation of total actual amount of the sediment, for calculation of the actual volume of water in current water level, or it can be used for creation of  area-capacity curves of the reservoir. This paper deals with the possibility of the creation of TIN (triangulated irregular network) model of the water reservoir bed and also for the assessment of the accuracy of the created TIN model. The idea of accuracy assessment is the evaluation of differences between modeled cross sections and the real elevations of the reservoir bed. Input data are the points collected with the GPS and depth measuring with the level staff (contact measuring) and the points collected with the GPS receiver and sonar during sailing in the reservoir (non-contact measuring). Then the data are processed in the ArcGIS 9.3 software and the TIN model of the reservoir bed is created. The cross sections of the model and the real elevations of the reservoir bed are created in the AutoCAD 2009 software. This method is demonstrated in the swimming pool in TopoľÄany. Bottom of the swimming pool is plain with good possibility to estimate real elevations of the points at its surface. The comparison of the modeled cross sections with the real bottom elevation offers evaluation of the accuracy of the method that can be obtained in the field work in the proper water reservoirs (fish ponds, irrigation reservoirs, etc.).

Keywords: TIN model creation, TIN model accuracy, water reservoir bottom topography