ABSTRACT
Step-pool mountain streams are unique bed morphologies exhibiting high spatial variability in flow parameters. Accurate velocity measurement at different sections in the stream stretch is required to develop better flow resistance models, which has applications in flood inundation modelling and construction of artificial fish passes. The present study is based on the field study conducted in a 100 m stretch of step-pool mountain stream in Meppadi, Wayanad, Kerala State, India. The study compares the velocity measurements obtained using an Electromagnetic Current Meter (OTT MF-Pro) and an Acoustic Doppler Velocimeter (Sontek FlowTracker2). A maximum percentage error of 28% and maximum error of ± 0.44 m/s is found between the instruments considering the sections inclusive of steps, step lips, base of steps, pools and cascades. Excluding the points of high self-aeration (base of steps), the maximum percentage error and maximum error reduced to 20% and ± 0.21 m/s, respectively.
