Use of GPS, Sonar, Acoustic Doppler, and 2D Hydraulic Modeling for Evaluating Changes in Riverine Habitat with Discharge

In this study, the latest riverine surveying techniques were used to gather data for use in a two-dimensional hydraulic model (RMA2) for the purpose of evaluating the changes in physical habitat with discharge. Global positioning systems (GPS) and sonar were used to map the bathymetry of a 4km stretch of river and Acoustic Doppler Profiler (ADP) data were used for calibrating the model. The two-dimensional model output was then used to create maps of meso-habitat for comparison against local fish abundance. Results suggest that integration of GPS and sonar is well suited to the collection of large accurate bathymetric data sets over large spatial domains in a relatively short period of time. Additionally, the ability to collect depth-averaged velocity with an ADP proved crucial to collecting a model calibration data set in deep fast moving water. While it was found that two-dimensional hydraulic modeling represented a significant improvement in the ability to map features related to physical habitat, specifically depth-averaged velocity and depth; the additional time and financial resources needed for this type of modeling were equally significant.