Use of telemetry in the development and application of biological criteria for habitat hydraulic modeling

Abstract

Habitat hydraulic modeling has arisen as the preferred tool for the prescription of ecologically acceptable flow regimes for projects that are striving to alter or reduce natural river flows. The biological/habitat components of these models are criticized and require more development. A research study was conducted on the West Salmon River, Newfoundland, Canada, to examine the influence of temporal and spatial elements of habitat selection on habitat hydraulic modeling. Juvenile Atlantic salmon (Salmo salar) were surgically implanted with radio transmitters and habitat selection was determined over varying flows, seasons, and on a diel basis. Experimental manipulation of flows simulated ‘peaking flow’ power generation allowing characterization of micro-habitat selection (depth, velocity, substrate) on a seasonal basis and in relation to flow variation. Habitat criteria (preference indices) were determined over the range of experimental conditions and used in simulations of weighted usable area (WUA). Curves derived at different flows had a large influence on WUA maxima, WUA trends in relation to discharge, and on spatial distribution of habitat suitability. This study has demonstrated the utility of telemetry in collection of data for development of temporally and spatially explicit habitat criteria. The study has also demonstrated the sensitivity of habitat hydraulic simulations to the selection of habitat preference indices.