Thesis (M.A.)--University of Colorado at Boulder, 2006
The goal of this study is to assess the relationship between the density of New Zealand mud snails (NZMS) and sediment transport in Boulder Creek, CO. Dimensionless shear stress, tau*, was estimated at three sites using a one-dimensional flow model. Frequency of sediment entrainment was evaluated for two values of critical dimensionless shear stress, tau* c. Changes in NZMS populations with discharge were determined and compared to average and lateral estimations of stress. While the data suggests there may be trends in the relationship between NZMS density and sediment transport, it is not clear that sediment transport governs the density and location of the NZMS. If the snails do use areas of lower stress as refugia, only flows that completely mobilize the bed (tau* > 1.5 tau c*) may reduce the NZMS population in Boulder Creek. Such flows occur one to two days/year at sites where snails are present
