Modeling fish habitat condition in ice affected rivers

Abstract

Hydro-morphological conditions in rivers can change significantly with the presence of ice. These changes can affect fish habitat, which can have important effects on fish mortality during the winter months. It is important to consider thermal-ice processes and their interactions with channel morphology in fish habitat models. In this paper, a review of wintertime fish habitat preference is presented and used to develop recommendations for habitat suitability curves for the winter period. A case study was used to illustrate the importance of considering the winter period when determining changes to fish habitat due to river restoration efforts. The impact of the dam removal on fish habitat quality for both open water and ice affected conditions were evaluated using existing water habitat suitability curves as well as the developed winter curves. River conditions were simulated with a two-dimensional hydro-thermal-ice-sediment river dynamic model coupled with an IFIM and PHABSIM type fish habitat suitability model. The model considers thermal-ice as well as sediment and bed change conditions in rivers to allow for more detailed habitat suitability evaluation than previous models. Simulations show habitat quality will improve for both open water and ice affected conditions in the restored reach of the St. Regis River.