August 2, 2012
Paul Ducheney
Superintendent – Hydro
Holyoke Gas and Electric Department
99 Suffolk Street
Holyoke, MA 01040-5082
Dear Paul,
The Connecticut River Watershed Council, Inc. (CRC) is writing in response to HG&E’s July 2, 2012 draft “Application for Non-Capacity Amendment of License.” CRC is a member of the Cooperative Consultation Team (CCT), and we have been an active participant in the path to design downstream fish passage for shortnose sturgeon (SNS).
Some of the key elements of the design as agreed upon and outlined in the application for license amendment are summarized as follows:
• Installation of a new angled bar rack in front of the turbines, with 6-inch rack bars and a 2-inch clear space.
• Solid overlays will be placed on the rack over units 1 and 2 on the full width of the rack down to a bottom elevation of 95 ft.
• Solid overlays will be added on the horizontal section of the rack just upstream of the weir and on the adjacent sloping portion of the rack next to the dam, down to the third structural member (as shown in Figure 1 in the February 2010 narrative for new CFD runs 21 and 22. Note the committee decided this was preferable than Figure 2).
• A cut-off wall will be added between the weir and the Unit 1 intake to prevent fish from entering the low velocity eddy in that region.
• HG&E proposes to install a new turbine at Hadley Unit 1. The unit proposed has a radial clearance of 0.085 inches, thicker entrance edges for the runner blades, and a smoother operation during high flow, new wicket gates to provide smoother passage through stationary water passage components.
• A potential flow allocation plan under the inclined rack configuration was distributed to us dated March 2012.
• At the downstream end, plunge pool will be designed according to revision 3 as modeled in CFD model Run L dated June 2011.
Proposed downstream fish passage enhancements
The current angled bar rack design is the best attempt over the course of more than five years of studies, designs, modeling, and comments by HG&E, their consultants, and the CCT. A design for passage through a low level outlet was eliminated due to costs. The present design has not been tested in the field, so we do not know for sure that sturgeon will find and use this passage route, and we also only have estimates of passage survival.
The overlays for the bar rack are described in the text of the draft application, but not really shown in the Exhibit F drawings.
The plunge pool at the downstream end looks promising in CFD analyses, and will likely result in improved downstream passage and survival for those fish that do make it into the weir.
As we have discussed in meetings, we have concerns related to lateral flow to the weir, flows across the depth of the water column, success in regard to getting sturgeon to swim to the surface in order to reach the weir, impingement and entrainment of eels (2” rack spacing is likely too big for eels), and fish reaction to the corner near the weir entrance. Despite what you have written up in Exhibit E, the radio tracking studies did not shed any light on how SNS currently interact with the project, and the radio tags were not able to be used on the age fish most likely to be moving downstream.
Some of our concerns will be addressed with post-construction monitoring, if coupled with changes that are deemed possible and likely to improve matters. In particular, we will be looking to ensure that what is put in place will ensure safe and effective passage for all diadromous fish, including eels.
Proposed upstream fish passage enhancements
CRC supports the proposed upstream fish passage enhancements, which include (i) removal of the projecting concrete wedge; (ii) a lateral narrowing of the then remaining fishway entrance back to the existing width; and (iii) removal of spillway construction entrance ramp. CFD analysis suggests these changes may enhance fish entering the upstream passage facilities.
Page 1 of the Exhibit F drawings appears to show the projecting concrete wedge still in place. This should be removed.
We also were under the impression that there would be a slanted ramp to the fishway entrance (on the downstream end) that would accommodate bottom swimmers such as SNS. No such ramp is mentioned or drawn. We expect to see this change in the final submission to FERC.
Proposed work at Hadley Unit 1
We have no specific comments on the replacement of Hadley Unit 1 other than our understanding is that the new unit will have characteristics that make survival more favorable for fish that are entrained into the works during downstream passage. Description of what is planned should be more detailed in the license amendment application to verify the benefits of the new unit.
Amendments to the Comprehensive Operations and Flow Plan (COFP)
CRC accepts the proposed changes to the COFP.
Schedule for Proposed Modifications
We appreciate the schedule provided in Exhibit C, particularly the development of a plan to monitor operations after construction. We also need to see a commitment from HG&E that, if the consultation team and HG&E agree that the study results indicate changes need to be made to the new structures, then HG&E will make modifications to improve fish passage and/or survival.
Thank you for the opportunity to comment on the draft license amendment application.
Sincerely,
Andrea F. Donlon, M.S.
River Steward
