Mitigation of Project Impacts 

The Woronoco dam is located below 95% of the habitat suitable for spawning Atlantic salmon on the Westfield River.  That is, only 5% of the available Atlantic salmon habitat of the Westfield River lies below the Woronoco dam and it cannot be reached by upstream migrants because of the first dam on the river.  Thus, the MA Division of Fisheries and Wildlife (MADFW) traps returning adult salmon in a trap and truck system to stock obtain eggs to stock salmon hatcheries.  After spawning, the fry are placed in the upper tributaries of the river.  (MADFW’s report of June 4, 2004 provides details about the actual number of spawning units of stream habitat and their location on the Westfield River).  After 1-3 years in the upper tributary habitat, the smolt must migrate down river to the Connecticut River and thence return to the Atlantic for the ocean phase of their life cycle.  Four of the five dams on the Westfield River have active downstream fish passage facilities in operation.

Woronoco's entrance to its new fish passage facility being installed in the 3/4" bar spaced trash racks

Indian River is the fifth dam on the Westfield River.  It was licensed by FERC and will soon have a similar fish passage system.  Each passage facility must undergo tests to demonstrate its effectiveness for passing smolt and adult eels.  In its July 10, 2003 letter commenting on the Indian River hydro project, MADFW stated that while “the applicant sees no incremental impact to wildlife as a result of restoration and operation, the Division believes that addition of another operating hydroelectric project on the Westfield River will have impacts on fish and wildlife.  Even a well constructed downstream fish passage system will not be 100% effective – leading to some loss of downstream migrants.  And while the installation of an upstream ellway will be an asset, adult ells are very difficult to guide around turbines and significant losses could be experienced.”  Indian River grants that no fish passage is perfect, nor is an unimproved dam effective in passing 100% of downstream migrating species on the river.  The MADFW comment singles out wildlife impacts, but does no give examples of ineffective passage facilities.  During discussion held on site, no examples of impacts on fish or wildlife resources was suggested.  Instead, consultation focused on how to make downstream passage for Atlantic salmon a more effective mitigation and where to install up and down river eel passage facilities, as well as pointing out that only one Atlantic salmon was trapped at the first dam on the river in each of the last three years.  We agree completely with the focus of the resource agencies, namely, to make the entire river system easier for fish passage, especially focusing on smolt migrating down river to the sea and back up river in future generations to rebuilt natural spawning for the Atlantic salmon.

Woronoco passed more than 2000 juvenile eels upstream in 2010.  It's middle ladder is the longest in NE.

As recommended during site consultation, the location and design of discharge flows into the bypass for habitat maintenance is best determined once the Indian River plant is operating. Both the USFWS and MADFW recommend that Indian River conduct a flow study the first field season following project start-up to determine the suitable discharge to protect the resources in the bypass reach.  The average river flow at the dam is 618 cfs and the installed hydraulic capacity is only 543 cfs.  On average, 55% of the river water spills over the dam without going through the turbines and probably more in the past due to manual setting of wicket gate openings where cycling the pond may have been a problem. 

This plant will be automatically  operated in a run-of-river mode. When inflow is equal to or less than the hydraulic capacity of the power plant, generating flow is throttled to maintain a stable impoundment elevation above the dam, plus a constant by-pass flow and discharge through the fish passage as seasonally required.  Flows greater than the hydraulic capacity plus the bypass and fish passage discharges will be spilled over the dam. This plan is similar to the Woronoco plant (FERC License 2631), three miles downstream of Russell dam, where automatic pond level controls regulate turbine flow.  Similar controls are installed at Indian River, including halting generation when inflow into the impoundment is less than the total of (1) the minimum capacity of the smallest turbine, plus (2) the fishway flows, plus (3) any additional bypass flow required as discharge into the bypass reach.

In correspondence with USFWS, Engineer Dick Quinn about the Indian River's design, he proposed locating 2 downstream fish passage facilities for Atlantic salmon smolt installed in the trash racks on each side of the two intake gates leading to a still tank with two 32" diameter outflow pipes to carry fish from the passage facility directly to the tailrace.  Forebay designs include a stop log gate upstream of the trashracks, which allows the intake works to be dewatered without draining the head pond.

Smolt passage effectiveness test with 60 radio tagged hatchery test fish

Another risk for fish passage comes from the trashracks.  Hydro operators think of racks as deterrents preventing fish mortality, but resource managers view racks not as screens, but as a point where fish could be hung up on the racks. The trashrack structure creates a filtering barrier between the river and the penstock intakes preventing debris (and most fish) from entering the penstocks and being hurt by the turbines. Trashracks span the entire 44-foot width on the river side of the gatehouse.  Velocity tests are made to detect any hot spot where the velocity is greater than 2 feet per second (fps).  The racks have only 3/4" bar openings to prevent infiltration and the rack supports are shaped to prevent a velocity increase at support points behind each trashrack.

ii.  Agency Recommendations for Indian River

Key recommendations provided by both MADFW and USFWS to mitigate impacts on fish resources include:

Project will furnish upstream and downstream passage for American eels designed in consultation with FWS and MADFW within 1 year of exemption issuance (DWF 7/804).

 The project will provide downstream fish passage for Atlantic salmon adults and smolts. The passage is to be designed in consultation with FWS hydraulic engineers. The facility concept was designed by FWS, see Appendix D.  It is similar to the design operating and soon to be tested at Woronoco Hydro (FERC 2631) and will operate from April 1 to June 15 and Nov. 1 to Dec. 31.  MADFW says within 1 year, USFWS says at start-up.

 The project shall participate in the trap and truck program for restoration of the Atlantic salmon on the Westfield by paying ¼ of the cost of the program that moves adult salmon from a trap at the first dam on the Westfield River (FERC 2608) to spawning habitat above the fourth dam (FERC 2986).

 The project will have to construct upstream anadromous fish passage facilities at this project when and on a schedule proposed by the FWS and/or MADFW.  Until a bypass discharge plan has been completed, 50 cfs will be discharge to the bypass reach, including the flow used for the fish passage facilities on each side of the dam.

Fish pass through the 32" diameter discharge pipe and drop into the Woronoco plunge pool to pass the dam

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