Effects of Spatial Data Acquisition on Determination of a Gravel-Bed River Geomorphology.

Bed irregularities of water bodies play a significant role in many hydraulic and river engineering experiments and models. Accurate measurement of river geomorphology requires great fieldwork effort. Optimizing the dataset size of measured points will reduce the time and costs involved. In this study, the geomorphology of a gravel bed river reach was measured using different spatial acquisition methods. Digital elevation models were created for each measurement method and the volumes of under/overestimation were calculated. The results show that the sampling methods had more effect on the accuracy of the interpolated geomorphology than the density of the measured points. By choosing an optimized sampling method, the measurement efforts decreased to less than 50%, with negligible errors of around 15 m³ and 10 m³ over and underestimation, respectively, in a water body area of around 2200 m². These findings help to provide more accurate geomorphological data with less effort as inputs for experimental and numerical models to derive better results. [ABSTRACT FROM AUTHOR]