af» NORMANDEAU City of Nashua
AFA ASSOCIATES June 18, 2019
ENVIRONMENTAL CONSULTANTS Page 8
e Determine the flow field conditions which exist in and around the fishway entrances and create a
series of color contour maps of velocity magnitude at a range of discharges for comparison with known
fish swim capabilities.
Agency Recommended Approach:
e Collect necessary data (bed topography, water velocities, water depth) under a range of discharges
and assemble a 3-D computational fluid dynamics model.
Suggested Approach:
© Push back on conducting 3D CFD modeling of the Project fisnways unless one of the proposed passage
studies indicate a lack of safe, timely and effective passage.
Study: Downstream American Eel Passage Assessment
Requestor: NHFGD
Requestor Goal & Objectives:
¢ Quantify the movement rate and relative proportion of eels passing via the various routes at the
project.
e Evaluate instantaneous and latent mortality and injury of eels passed via each potential route.
Agency Recommended Approach:
e Evaluate the timing and route of downstream passage for adult eels at Mine Falls using radio-
telemetry.
e Evaluate turbine passage mortality for adult eels using the turbines, downstream bypass and spillway
with the HI-Z balloon tag methodology.
Suggested Approach:
® Push back on conducting a HI-Z balloon tag study. Downstream passage survival for adult eels will be
considered as part of the Desktop Impingement/Entrainment Survivability Assessment.
e Push back on additional telemetry evaluation of eels at Mine Falls until results from the Alden-DOE
bypass effectiveness study results are available. It is my understanding that eels used in that
experiment will be radio-tagged and should provide some insight into egress from the power canal.
Study: Desktop Impingement/Entrainment Survivability Assessment
Requestor: City of Nashua
Requestor Goal & Objectives:
e Provide a description of physical characteristics of the Mine Falls Project (including forebay
characteristics, intake location and dimensions, approach velocities, and rack spacing).
e Analyze target species for factors that may influence vulnerability to entrainment and mortality.
e Assess the potential for impingement and entrainment for target species.
e Estimate turbine passage survival rates.
e Estimate total project survival considering all passage routes for target species at the Project.
Suggested Approach:
