Project Summary

The Salmon Trout River (STR) is the only river on the south shore of Lake Superior known to sustain a reproducing coaster brook trout population. Related studies demonstrate that brook trout tend to select spawning sites, based on the presence of groundwater discharge into the river. The results of these studies also suggest that groundwater presence is vital to the reproductive success of CBT. Previous studies of the STR have characterized the life history strategies and ecology of CBT, but to date no study has investigated the influence of groundwater on CBT spawning habitat in the STR. We hypothesize that spatial distributions of groundwater inflows through river-bottom sediments are a critical factor in the selection of spawning sites.

In this study, high-resolution data collection methods are implemented to quantify the interaction between the groundwater and surface water in order to verify the presence or absence of groundwater discharge into the river at sites that support a reproducing population of coaster brook trout. By independently inverting temperature and pressure measurements the exchange of water between groundwater and surface water can be simultaneously analyzed, permitting a more precise estimate of groundwater velocity.