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Hydro dams’ owner must address erosion

Federal agency orders Great River Hydro to revise reports

—Federal regulators say the owner of three Connecticut River hydroelectric dams needs to take another look at erosion issues.Great River Hydro is seeking renewed Federal Energy Regulatory Commission (FERC) licenses to operate the Wilder, Bellows Falls, and Vernon hydro dams. As part of that process, the Massachusetts-based company had submitted two years of erosion-monitoring data.But in a recent decision, federal officials said the company’s analysis was “incomplete and inconsistent with what was required in the approved study plan.” The commission ordered Great River to submit revised erosion reports by Nov. 15.That’s good news for Connecticut River Conservancy. The Greenfield, Mass.-based nonprofit had been critical of Great River’s studies and wants more information on the hydro dams’ possible effects on riverbank erosion.“This might help us make better recommendations about how we want them to operate in the future,” said Andrea Donlon, a river steward at the Conservancy.Jennifer Griffin, a Great River staffer who handles federal licensing and compliance, said the company is “still reviewing the contents of the FERC letter and determining a response but cannot offer any details at this time.”Griffin also noted that the company has 30 days to decide whether to ask the commission to reconsider its request.

13 properties

—Earlier this year, Great River Hydro acquired 13 hydroelectric properties on the Connecticut and Deerfield rivers. Great River, which is a subsidiary of Boston-based ArcLight Capital Partners, paid TransCanada nearly $1.07 billion for the properties.TransCanada already had been pursuing relicensing for the Wilder, Bellows Falls, and Vernon dams for several years. Those licenses are due to expire at the end of April 2019.Soon after Great River took control of the dams, an administrator said the company wouldn’t miss a beat in the relicensing process. In fact, federal regulations required Great River to submit a voluminous relicensing application by May 1 — less than two weeks after becoming the property owner.Due to that tight time frame and the complexity of the process, some environmental studies associated with relicensing aren’t yet finished. But a Great River Hydro representative in June said the company had wrapped up all erosion studies.Erosion has been a hot-button issue in communities where some say river fluctuations from hydroelectric operations have impacted riverbanks much more than natural flows would have.Connecticut River Conservancy had been among several nonprofit and governmental entities that took issue with Great River’s erosion studies in connection with the federal relicensing process.In comments filed with the federal commission in May, the conservancy — which enlisted an engineering consultant to review Great River’s studies — said the company “failed to rely on generally accepted scientific methods” and “otherwise reached conclusions that the science, data, or evidence do not support.”It fell to FERC to weigh such objections against Great River’s reports. And commission staff, in a determination issued July 21, sided in part with Great River.For instance, federal officials rejected calls for the company to perform additional statistical analysis of its erosion data. And the commission declined to compel Great River to collect additional groundwater data as it relates to erosion.

Work to be done

—But FERC did send Great River back to the drawing board in several respects, including:• The commission says Great River must file a revised study report in November analyzing “critical sheer stress” — defined as the point at which the force of a river picks up sediment — and near-riverbank water velocities at 21 monitoring sites.The company also is supposed to consider potential connections between those two issues and the hydro dams’ operations.The ruling appears to validate concerns expressed by the Connecticut River Conservancy and the New Hampshire Department of Environmental Services. Those organizations had argued that Great River’s study method “fails to capture the complexities of the erosion processes,” according to federal documents.• FERC also wants Great River Hydro to revisit its measurements of river velocities.The company measured velocities at six monitoring sites and found that, “under normal project operation,” river flows were below the speed required for erosion.But federal officials say Great River should gather information about riverbank water velocities associated with multiple water elevations — not just normal dam operations. Also, the company must submit an analysis of river velocities at its 15 other monitoring sites.“Accurate velocity assessments are necessary to determine the conditions under which sediment is transported from bank areas,” the FERC order says.• In its revised November report, Great River also is supposed to include more information about the relationship between observed erosion and riverbank characteristics including soil types.FERC notes that “stream bank erosion may be more likely to occur with certain soil types” when subjected to fluctuations in water elevations.Even after Great River Hydro submits its revised erosion reports, there will still be a long way to go in the relicensing process. In a meeting in Westminster earlier this year, a Great River representative described the process as lengthy, complicated, and expensive.But Donlon said the conservancy and other participants in that process want as much accurate information about the dams and the river as possible.Donlon acknowledges that there are river issues Great River Hydro doesn’t control. But, she added, “we want to know what effect they’re having on the part they can control.”

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Originally published in The Commons issue #420 (Wednesday, August 9, 2017). This story appeared on page A1.

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