Inflatable flashboards meet historic dam

A hydropower project in Lowell, Massachusetts won the right to replace wooden flashboards with an inflatable pneumatic crest gate system -- and now seeks to modify provisions requiring specific actions to mitigate impacts on historic properties.

The Lowell Hydroelectric Project is located on the Merrimack River.  While the project does not occupy any federal land, it is located within the administrative boundary of the Lowell National Historical Park.

On July 6, 2010, project licensees Boott Hydropower, Inc., and Eldred L. Field Hydroelectric Facility Trust filed an application to amend the license for the Lowell Hydroelectric Project.  The licensees requested authorization to replace the existing Pawtucket Dam’s wooden flashboards with a pneumatic crest gate system, and to change the configuration of the wooden flashboard system while the new crest gate system is being constructed.  Also called "inflatable flashboards", a pneumatic crest gate system allows the dam operator to increase or decrease the effective height of the flashboard system remotely.

The application was contested. Among other things, Pawtucket Dam is listed on the National Register of Historic Places as part of the Lowell Park and two historic districts, one of which is a National Historic Landmark.  Participants in the license amendment case disagreed about whether it is acceptable to alter the crest control structure on top of the dam and whether the effects of
doing so can be adequately mitigated.  Some concern related to the visual impact of the inflatable flashboards, relative to the project's historic context.

But in 2013, the Federal Energy Regulatory Commission issued an Order Amending License allowing the licensee to replace the wooden flashboards with a pneumatic crest gate system.  The Commission found "that the proposed pneumatic crest gate system can be installed without unacceptably altering the dam or adversely affecting the park and historic districts."  The Commission therefore granted the licensees’ amendment request, subject to additional conditions.
 
Those conditions included a paragraph in the Order requiring the licensees to take certain actions "to mitigate any adverse effects on historic properties of installing the pneumatic crest gate system."  These license required consultation with the Massachusetts State Historic Preservation Officer and the Lowell National Historical Park to the extent possible.  The conditions also included specific measures including interpretive exhibits, a design for the compressor house featuring "materials and colors that are compatible with the historic fabric of the adjacent architecture, to ensure that the compressor house resembles nineteenth century buildings in Lowell," color and appearance requirements for the inflatable flashboard system.

But National Park Service subsequently indicated its willingness to waive these design-related mitigation requirements.  According to a February 2, 2016, letter from the National Park Service, "it is National Park Service's policy not to make new construction look historic in appearance."  Two days later, the licensee applied to the FERC to remove these mitigation requirements.  That application notes that eliminating these requirements "decreases material ordering time and crest gate system installation time for this long-awaited improvement."

Comments on the application, motions to intervene, and protests are due by April 11, 2016.