Bunntransport i Vekveselva: Et felteksperiment for å undersøke egnetheten til passive integrerte transpondere i fjellelver

Abstract

This  thesis  addresses  the  difficulties  related  to  measuring  of  bedload  transport  in  steepmountain rivers. It is important to learn more about how eroding particles move in rivers because of the problems countries like Norway might face with increasing flood events in the future. The main focus for this thesis is to study the bedload transport in Vekveselva in Trollheimen, Norway. The problems to be discussed are (1) which of the tracer methods, passive integrated transponers or visuall tracers, give the best data for analyzing bedload transport, and (2) if the methods used in this investigation are able to determine if the two theories, size-selective or equal mobility, best describes the bedload transport in Vekveselva. Other methods used are impact sensors, pebble counts and grain distribution analysis. The results were difficult to interpret due to three major flood events during the summer of 2010 causing the loss of many tracers. Still there is reason to conclude that which the literature suggests; (1) that passive integrated tranpondertags gives a bigger percentage of recaptures of tracers than with visual tracers and therefore more data to analyze at a later stage, and (2) that size selective is the main form for bedload transport during low flow and equal mobility is more relevant during flood events.