Hydraulic modeling of mussel habitat at a bridge-replacement site, Allegheny River, Pennsylvania, USA

摘要: Abstract The Allegheny River in Pennsylvania supports a large and diverse freshwater-mussel community, including two federally listed endangered species, Pleurobema clava (Clubshell) Epioblasma torulosa rangiana (Northern Riffleshell). It is recognized that river hydraulics morphology play important roles mussel distribution. To assess the hydraulic influences of bridge replacement on habitat, metrics such as depth, velocity, their derivatives (shear stress, Froude number) were collected or computed. objectives project to evaluate data at reference site compare those findings bridge-replacement site. used support statistical analysis, which establishes correlations between count hydraulics, numerical model forecast habitat based statistics. ArcGIS was selected manage generate grid compute area statistics for 3319, 4.9-m × 4.9-m cells (cell) total count, shear number. Wilcoxon Rank Sum test indicated no significance variables; however, trellis graphs account spatial variability set. For flow conditions measured, per cell greatest sections where (1) velocities range from 0.061 0.21 m/s, (2) stresses 0.48 3.8 dyne/cm 2 , (3) numbers 0.006 0.04. Based targets established, results suggest an additional 2428 m 30-percent increase suitable could be generated replacement-bridge when compared baseline condition associated with existing same location. study did not address substrate, acid mine drainage, sediment loads tributaries, surface-water/ground-water exchange habitat. Future studies include methods quantifying channel–substrate composition distribution using tools hydroacoustic echosounders specifically designed calibrated identify bed populations, surface-water ground-water interactions, high-streamflow event.