May 1, 2017


Honorable Kimberly D. Bose Secretary

Federal Energy Regulatory Commission

888 First Street, NE

Washington, DC 20426


Re:     Northfield Mountain Pumped Storage Project No. 2485-063

Turners Falls Project No. 1889-081

Connecticut River Conservancy Comments on FirstLight Study Reports filed March 1, 2017; Request for Study Modification to Require Compliance with the RSP. 


Dear Secretary Bose,

The Connecticut River Watershed Council, Inc. (CRWC), now doing business as the Connecticut River Conservancy (CRC), is a nonprofit citizen group established in 1952 to advocate for the protection, restoration, and sustainable use of the Connecticut River and its four-state watershed.  We have been participating in the relicensing of the five hydropower facilities on the Connecticut River since the beginning of the process in late 2012.  We have reviewed the set of Study Reports that were posted by FirstLight on March 1, 2017.  CRC attended the study report meeting held on March 16, 2017.  Below are our comments.

Study No. 3.3.5  Evaluate Downstream Passage of American Eel

The Study Report neglected to note that Unit 1, one of the four turbine units at Northfield Mountain, was taken out of service on August 31, 2015 and returned to service on February 17, 2016 (letter from FirstLight filed with FERC on March 2, 2016).  The report should have made note of this as a deviation from the Revised Study Plan (RSP) dated August 14, 2013, and also in assessing entrainment results from Northfield Mountain.

Pages 4-19 to 4-21 of the report indicate that Northfield Mountain operations potentially entrain a high percentage of fish (2% entrained plus 37% entering an “unknown state”).  Project operations may be a significant threat to eels, and should be mitigated under the new license.

Study No. 3.3.10  Assess Operational Impacts on Emergence of State-Listed Odonates (2nd year)

This study was not conducted as provided for in the approved study plan.  The RSP reassured stakeholders that the many years of existing data in the Turners Falls impoundment could be used to assess project effects, as listed below:

  1. The first objective of the study as written in the Revised Study Plan (RSP) dated August 14, 2013, was, “Synthesis of existing data, supplemented with field surveys, to characterize the assemblage structure and emergence/eclosure behavior of odonates in the project area.”
  2. The RSP on page 3-238 stated, “To some extent, a thorough review of existing information will provide adequate biological information for an impact assessment using the hydraulic model…, but field observations are planned to fill critical knowledge gaps by conducting surveys in both the Turners Fall Impoundment and downstream from the Turners Falls Dam.”
  3. Task 1 of this study as listed in the RSP was to gather existing information on species composition in the proposed study reaches and to summarize the life history and ecology of these species.
  4. Section 4.1 in the Interim Report for Study 3.3.10 dated April 2015, stated, “Information on the odonate assemblage in the project-affected reaches of the Connecticut River will be gathered from publications, reports, and relevant case studies. Experts who were involved with the dragonfly studies in the Turners Falls Impoundment in the 2000s have been contacted to provide expert opinion and in some cases unpublished data. The life history and ecology, and particularly emergence and eclosure behavior, of these species and species groups will be summarized in the final report.”

The synthesis of existing data has never happened and was not presented in any study report submitted thus far.  The entire report uses only the “supplemental” field surveys from Barton Cove, the bypass reach, and below Cabot Station.  At the study report meeting held in March, FirstLight’s consultant explained that the existing data was not sufficient for the impact assessment.  This was not explained in the study report

To better understand the type of information available in previous studies, CRC obtained copies of the following reports from the Massachusetts Natural Heritage and Endangered Species Program (NHESP).  We will not be divulging information about specific species and locations in this comment letter.

  1. Martin, 2006. Impact of bank stabilization technique, boat wake, water level rise, and predation on the mortality rate, and eclosure success of odonate nymphs in Gill, MA: Results of the 2006 Field Season. Prepared for the Massachusetts Natural Heritage and Endangered Species Program.
  2. New England Environmental, Inc., February 29, 2008. 2007 Year-End Report, Dragonfly Studies Within the Turners Falls Pool, Connecticut River, Bank Stabilization Projects. Prepared for FirstLight Hydro Generating Company.
  3. New England Environmental, Inc., January 30, 2009. 2008 Year-End Report, Dragonfly Studies Within the Turners Falls Pool, Connecticut River, Bank Stabilization Projects. Prepared for FirstLight Hydro Generating Company.
  4. Martin, 2010. The Transition Zone: Impact of Riverbanks on Emergent Dragonfly Nymphs. Implications for Riverbank Restoration and Management.  PhD dissertation at Antioch New England.


The following list includes reasons why a synthesis of previous studies would be useful for relicensing:

  • A synthesis of existing data could compare how the species found in the field sites 2014-2016 compare with those found in the impoundment at monitoring sites 2001-2008 and other years, which would give the stakeholders an understanding whether or not the study captured the species that are present in the study area.
  • A synthesis of existing data could compare how the abundance of species found at the field sites 2014-2016 compared against the previous study years, which documented a wide range from year to year.
  • A synthesis of existing data could compare how the distance to eclosure observed at the field sites 2014-2016 compared to the distances measured at monitoring sites 2001-2008. This is especially important because previous studies never measured height above water to eclosure, so we need to know if the distances are within a range that has been observed in other studies.
  • A synthesis of existing data could summarize the mortalities observed of species due to project operations and boat wakes, and compare that to the risk assessment results of this study. For example, in 2008, one mortality of Gomphus vastus from project operations was noted but Table 3.6-4 does not indicate a risk in the Turners Falls impoundment.

Moreover, the study includes the following areas of flawed analysis.

  1. The RSP on page 3-241 stated that, “In addition, the influence of water level, habitat characteristics (substrate, vegetation cover, elevation), and weather conditions on emergence distance will be determined using correlation and regression analysis.” Correlation and regression analysis never took place.  The study reported eclosure substrate by species (see Table 3.4-1) but didn’t indicate how emergence distance (or height, as the study became focused on) varied by substrate.  This is important because, for example, the Turners Falls impoundment had no observations upstream of Barton Cove and previous studies had shown that emergence distance varied by substrate and by location upstream or downstream of the Northfield Mountain tailrace (Martin, 2010).  One of the operational effects of Northfield Mountain since it began operation has been an increase of erosion in the impoundment, which has led to a greater prevalence of banks lacking vegetation than elsewhere in the study area and repaired banks, making rip rap more common in the impoundment than elsewhere in the study area.  As such, this study report did not adequately assess operational impacts in the Turners Falls impoundment.
  2. Page 5-209 of Study Report 3.2.1 (April, 2017 version), states, “Based on these data, the rate of rise and fall of the water level based on boat waves is approximately 0.2 to 0.66 feet per second (or 720 to 2400 feet per hour over the limited range of wave from crest to trough). This can be compared with the rate of rise and fall of the TFI fluctuations that are generally on the order of a few tenths of a foot per hour. The rate of change in water level for boat waves therefore ranges from about 1,000 to 10,000 times larger than for TFI fluctuations caused by variability in flow or hydropower operations. Compared against high rates of water level fluctuation that occur less frequently, the ratio of boat wave induced change to TFI level induced change would be smaller than the factor of 1,000 times. Compared against the low rates of TFI water level change that occurs more frequently, the ratio would be even greater than the factor of 10,000. This demonstrates that boat waves are orders of magnitude more intense in terms of rapidity of change of water level than TFI fluctuations caused by variability of flow or hydropower operations.”

The rationale for the 0.23 ft/hour “correction factor” used in this study is not explained and does not seem to be based on data from Study 3.1.2.  Moreover, it completely underestimates the instantaneous nature of impact – a boat wake immediately increases the river height; it is not averaged over an hour.

  1. The 2009 Dragonfly Studies Report on Figure 8 shows the average height of boat wakes on weekends versus weekdays for the years 2006, 2007, and 2008. Weekday boat wakes ranged in height between an average 2.51 inches in 2007 to 6.10 inches in 2008.  Weekend boat wakes ranged in height between an average 3.90 inches in 2007 to 6.70 inches in 2007.  Comparatively, the December 2016 Study 3.3.10 Study Report added a correction factor of 0.23 ft (or 2.76 inches) to the MHR-95% (the 95th percentile Maximum Hourly Rate of Change in ft/hr).  The MHR-95% used in Study 3.3.10 varied by HEC-RAS transect, but was in the range of 0.66 to 0.89 ft/hour or (7.92 to 10.68 inches/hour). It appears that the boat wave height used in Study 3.3.10 is underestimating the impact on odonates from boat wakes.
  2. A note at the bottom of Tables 3.6-6 and 3.6-7 indicates that Transect 2895 was not used in the boat wake analysis because it is located in Barton Cove, a no-wake zone. This is interesting, given that Study 3.1.2 cited “boat wakes” as being a main cause of erosion in Barton Cove.
  3. To analyze risk, we are mainly concerned about whether the eclosure height in the 2-hour period falls within the maximum elevation change of this 2 hour period. To look at this, averages of rates of change over years do not represent a “worse-case scenario.”  A low summer flow combined with 4 turbines generating at Northfield Mountain would represent a worse case scenario.  The HEC-RAS transect closest to Northfield Mountain, 25845, is listed as having a maximum hourly rate of change of 0.74 ft/hour.  Over a 2-hour period, this would be 1.48 ft.  I scanned through the logger data for Study 3.3.9, and found an example date of July 2, 2014 in which the logger located 1 km downstream of the Northfield Mountain tailrace (a similar location to HEC-RAS transect 25845) measured at 181.22 ft at 14:30 and at 183.08 at 16:30, a difference of 1.86 ft.  It would be better to model the largest 2-hour change in elevation over the study period, that represents the 95th %.

CRC recommendations:  We request the following modifications to the study report under 18 CFR §5.15(d)(1).  We recommend that FirstLight prepare an addendum to the study report that includes the following modifications:

  1. A summary of existing data and comparison of existing information against the risk assessment results in Study 3.3.10.
  2. A revision of the risk assessment methodology that shows the likelihood of impact based on water level changes during the critical time period (usually 2 hours), not a critical rate of change. For example, Table 3.3-2 shows the median vertical crawl heights for species groups.  Using the Gomphus group for example, 5% critical height percentile was 1.69 ft.  To analyze potential impacts from operational fluctuations, take the maximum hourly rate of change, say 0.89 ft/hour at transect 2895.  If we assume an eclosure time of 2 hours, then this would be 1.78 ft over two hours.   This would imply that there could be an impact.  Add on top of that an instantaneous boat wake (of something based on existing data, like 0.66 ft) for a maximum impact of operational and boat wave impact of 2.44 ft.
  3. The boat wake analysis needs to be based on a number shown in existing studies and reflecting an instantaneous water level change, not averaged over an hour.
  4. FirstLight either needs to analyze the impacts to odonates from boat wakes in Barton Cove, or revise the erosion causation study to eliminate the impact of boat wakes in this area.

Study No. 3.3.19  Evaluate the Use of an Ultrasound Array to Facilitate Upstream Movement to Turners Falls Dam by avoiding Cabot Tailrace

The RSP stated that in task 2 of this study, “The CFD modeling will be coupled with the telemetry results, passage counts, and environmental variables (water temperature, river flow) to understand which conditions are preferable for guiding migrating fish to the entrances.”  A revised study plan dated January 2016 stated, “Environmental and operational data will be recorded and reported during each test period to understand which conditions are preferable for guiding migrating fish to the entrances.” The January 2016 RSP indicated on page 7 that environmental data included temperature data, and operational data included hourly Montague USGS gage flows, Cabot Station hourly discharges, Station No. 1 hourly discharges, and Turners Falls Dam spill flow.  CRC could not find any analysis of temperature, Station No. 1 discharges, or Turners Falls Dam spill flow in the report (a regression model compared fish movement with Cabot generation, Montague gage flow, and bypass flow).  The report looked at the impact of the ultrasound array on fish passage numbers on the Cabot ladder only, whereas the RSP had said that the study would aid in the understanding which conditions are preferable for guiding migrating fish to the “entrances,” not one entrance.

CRC recommendation:  The study report should have reported these deviations from the RSP, indicating the rationale.  FirstLight should explain the rationale for the deviations in its response.  FirstLight should also discuss what information can be presented to stakeholders to aid in the understanding of conditions that are conducive to successful entrance and passage at the three fish ladders.

Study No. 3.3.20  Ichthyoplankton Entrainment Assessment at the Northfield Mountain Pumped Storage Project

The Executive Summary fails to mention that the real reason the study was done a second season is that the 2015 study was started mid-way through the shad spawning season, such that the peak spawning was missed.

The report in section 4.1 states, “There does not appear to be a trend with river flow and entrainment density,” citing a comparison of the daily organism densities with daily average flow at the Montague USGS gage.  This comparison is meaningless and does not comply with the RSP and is not “generally accepted practice in the scientific community.”  The number of entrained shad eggs and larvae would be related to the number of pumps operating at Northfield Mountain and the river flow coming from upstream.  The average flows at Montague do not have a close relationship with the flow happening during the pumping at Northfield.

The FERC study plan determination dated January 22, 2015 stated, “River discharge could potentially affect estimates of both ichthyoplankton densities and entrainment rates.  For example, if the same number of adult shad spawn at high flow conditions and at low flow conditions and produce identical numbers of eggs and larvae at both conditions, the resulting high flow ichthyoplankton density estimate may be lower than the low flow estimate because the additional water associated with high river flow conditions “dilutes” the eggs and larvae. Similarly, river discharge may affect entrainment rates because a given level of pumping at the Northfield Mountain Project may remove a larger proportion of available water at low flow conditions than at high flow conditions. Including river discharge in the analyses of ichthyoplankton density and entrainment rates would require minimal additional cost (section 5.9(b)(7)) and could inform the development of license requirements (section 5.9(b)(5)). Therefore, we recommend that FirstLight include river discharge in its analyses of ichthyoplankton density and entrainment rates.”

CRC commented in 2016 that this analysis was lacking in the 2015 report in our May 2, 2016 letter (we also submitted a corrected version of this letter on May 3, 2016) letter and again in a response on June 8, 2016, specifically asking for Vernon flows.  FERC concurred in their Study Plan Determination dated June 30, 2016, stating that, “Therefore, as required by the January 22, 2015, letter, FirstLight should include river discharge in its analyses of 2015 and 2016 ichthyoplankton density estimates and entrainment rates in its supplemental report for the 2016 study.”

The river flow analysis was a topic of discussion at the study report meeting held on March 16, 2017.  FirstLight stated that the level of effort to do an accurate assessment of upstream river flow and project operations on shad egg and larvae entrainment was too high.  FirstLight has had two years to sort out that issue and recommend a solution to stakeholders, and this was the first time we heard of this difficulty.

CRC recommendation:  The Report on page 1-3 states that a future filing will include an estimate of ichthyoplankton entrainment for FirstLight’s proposal to expand the Upper Reservoir’s Operating Range.  As part of that filing, CRC recommends that FirstLight include the flow analysis as required by FERC.  Otherwise, we have two data points from 2015 and 2016, and we will have to make our own conservative assumptions on impact of project operations and flows.

Study No. 3.8.1  Evaluate Impacts of Modes of Operation on Flow, Water Elevation, and Hydropower Generation

This study deviates from the approved RSP in several ways.


  1. The RSP said that the study report would include, “a table comparing annual and monthly baseline generation with the same for the various production runs. The net loss/gain and percentage loss/gain will be computed relative to the baseline model.”  The report shows annual generation, but no monthly information has been given.


  1. The RSP said that, “For select periods, hourly hydrographs will be developed for the baseline model and compared with the same for a select number of Production Runs.” The report showed the observed vs. calibration and baseline run results for only the period 7/19/2002 to 7/26/2002.  We have no idea what the rest of the year looks like.


The report states that Production Runs will be completed later in the relicensing process.  For now, the report compares the baseline and calibration runs with the actual results from 2002.  CRC is concerned that the model runs show large deviations from the actual data:


  • The monthly flow duration curves (Figures 4.1-2 through 4.1-5) show large differences.


  • Figure 5.2-2 indicates a large difference (between 1,000 and >2,000 MWh) between observed and modeled Cabot Station baseline runs during all times of day. Figure 5.2-3 indicates a large (1,000 to 2,000 cfs) difference between observed (2002) and modeled Station 1 power output during all times of day.


  • The timing and maximum and minimum flows for the day differ between the modeled runs and the calibration and baseline runs. For example, in Figure 5.1-5, later in the day on July 24, there is a 8,000 cfs difference between the observed (2002) and the modeled peak flow.  This is just as important, or more so, than the flow duration curves of Figure 5.1-1 and 5.1-2.   Assessing certain impacts using the model is likely to be inaccurate.


With regard to the representative years of 2002 and 2009, FirstLight has not presented any data that help us understand if these years are representative of current or future operations.


CRC recommendation:  FL should prepare an addendum that shows more time segments than one week in July and analyzes the model on a monthly basis so we can have more confidence in the model’s ability to perform scenarios with relative accuracy.  Stakeholders need to have a sense of the model’s ability to accurately model the magnitude and timing of bypass flows, hydropower releases and river levels in the impoundment and downstream of Cabot Station.


CRWC requests that these studies be modified pursuant to 18 C.F.R. § 5.15(a) and (d) (1) to fully address these comments.  We appreciate the opportunity to provide comments on the studies submitted on March 1, 2017.  I can be reached at or (413) 772-2020 x.205.



Andrea F. Donlon

River Steward