Comparison of Watershed Macroscale Approaches against Microscale for the South Fork Clearwater River, Idaho

We analyzed relationships between Index of Fish Density (IFD) and man-made disturbances, watershed parameters, habitat parameters, water quality parameter, and climate parameters for the 61 HUCs (Hydrological Unit Code) at the macroscale for the South Fork Clearwater River basin in Idaho and 15–20 reaches for Red River and Newsome Creek within the South Fork Clearwater River Basin. Assessment results show that consideration of only the watershed-wide parameters and man-made disturbances is inadequate and yields uncertain results. On the other hand, focusing on a specific stream site alone does not account for all significant parameters. Incorporating both fine and coarse scale parameters in any assessment model will improve the correlations and lead to better results.