Nick Bouwes, ELR
Carl Saunders, ELR
Joe Wheaton, USU
Pete McHugh, ELR
Eric Wall, ELR
Chris Jordan, NOAA
The ability to predict the effects of stream restoration or extrapolate knowledge gained to new situations is highly dependent on the degree to which a model represents actual mechanisms. Ecohydraulic fish habitat models that are mechanistically based have successfully predicted fish location and abundance. In ISEMP and CHaMP, we developed a monitoring protocol that allows for the use of net rate of energy intake (NREI; energy gains through capture and consumption of drifting invertebrates minus energy cost through swimming to maintain a foraging position) models, where temperature and food availability (drift) is used as supporting information to hydraulic models to estimate habitat quality and carrying capacity.
The NREI model uses a foraging model that incorporates depth, velocity and prey abundance (drifting invertebrates) to predict prey encounter rates, capture success, and consumption rates at locations throughout the modeled hydraulic environment of a reach. Bioenergetics models then estimate gross rate of energy input (GREI) from prey consumed and swimming costs (SC) at the focal velocity under a given temperature, with GREI-SC=NREI. To estimate carrying capacity, the highest NEI value on each modeled cross section is compared to a user-defined NEI threshold and locations meeting or exceeding the NEI threshold (e.g., NREI>0) receive a fish. A minimum distance between fish is set by the fish territory size. Placement proceeds downstream until the last location has been evaluated for fish placement, with carrying capacity equal to the sum of all fish in the reach
Findings and Uses
Data collected using the CHaMP protocol has allowed for application of a Net Rate of Energy Intake (NREI) ecohydraulic model to:
- Predict potential improvements to carrying capacity as the result of restoration actions,
- Help identify types of restoration actions and areas where such actions can be most cost-effective, and
- Allow for eventual extrapolation to the network scale to help determine the most cost-effective restoration actions and where to apply them.
This approach can be upscaled to address population-level predictions, and was recently used in overall life-cycle assessment of steelhead population persistence following a large-scale restoration effort in the Middle Fork of the John Day River in Central Oregon (Wheaton et al. 2017).
Wall, C. E., N. Bouwes, J. M. Wheaton, S. N. Bennett, W. C. Saunders, P. A. McHugh, and C. E. Jordan. 2016. Design and monitoring of woody structures and their benefits to juvenile steelhead (Oncorhynchus mykiss) using a net rate of energy intake model. Canadian Journal of Fisheries and Aquatic Sciences:1-12.
Wall, C. E., N. Bouwes, J. M. Wheaton, W. C. Saunders, and S. N. Bennett. 2015. Net rate of energy intake predicts reach-level steelhead (Oncorhynchus mykiss) densities in diverse basins from a large monitoring program. Canadian Journal of Fisheries and Aquatic Sciences.
Wheaton, J. M., P. McHugh, N. Bouwes, C. Saunders, S. Bangen, P. Bailey, M. Nahorniak, E. Wall, and C. Jordan. 2017. Upscaling Site-Scale Ecohydraulic Models to Inform Salmonid Population-Level Life Cycle Modelling and Restoration Actions – Lessons from the Columbia River Basin. Earth Surface Processes and Landforms: n/a-n/a.