34 Providence Street
Portland, ME 04103
Tel. (207) 773-8190 Fax (206) 984-3086
Notice of Certification Application Filing
Jackson mills Hydroelectric Project
(FERC No. 3229)
Notice:The following description of the Jackson Mills Project has been provided to LIHIby the applicant and LIHI is reproducing it below without any representation as to its accuracy or completeness.
Portland, Maine (January 31, 2010) – The Low Impact Hydropower Institute (LIHI) announced today that Essex Hydro Associates (“Essex”) has submitted an Application for LIHI Certification for theJackson Mills Hydroelectric Project (“Project”).The project, which is located on the Nashua River holds a FERC exemption which was issued in April 1984 (FERC No. 7590) for the operation and maintenance of the run-of-river 1 Mw Project.
The Jackson Mills Project is located on the Nashua River approximately 700-feet downstream from the crossing of Route 3 (Main Street) in Nashua New Hampshire. The area in the vicinity of the project is urban in character and typical of an old New England manufacturing city. The Nashua public library is located on the south bank of the river. The former powerhouse on the north bank currently houses a restaurant, which contains some of the features of the old operation. The new powerhouse was constructed adjacent to the old powerhouse with the turbine inlet located beneath the restaurant.
The land uses along the north side of the river to the east of the restaurant are predominantly industrial and to the west they are commercial. On the south side of the river the land usage to the east of the library is predominantly urban residential with commercial uses lying to the west. Along both banks above and below the dam the vegetation consists of planted ornamentals and those types typical of disturbed ground.
The 180-foot long by 33-foot high dam is a gravity-type masonry structure with a concrete cap and a concrete extension and concrete-faced stone gravity-type abutments. Upstream and downstream fish passage is provided at the project by an Alaska steep-pass fishway and a stainless steel bypass pipe. The 40-acre impoundment has a normal maximum water surface of 116.6-feet NGVD. The Project operates in a run-of-river mode. The powerhouse which is located at the north dam abutment houses a 1 MW turbine generator.
The Nashua River has a total drainage area of 529 square miles, with 88 square miles being in New Hampshire, and 411 square miles in Massachusetts. The net drainage area available to the Jackson Mills Project is 410 square miles as 119 square miles are intercepted to supply water to the Massachusetts cities of Boston and Worcester.
For thousands of years, the watershed has been used by humans. Today it retains much of its agrarian and early industrial past while actively participating in the high technology economy of the late twentieth century. The watershed's classic New England villages now shelter those who create our current age, while its waters, wetlands, and forests still shelter many of the species that have been here since the retreat of the glaciers.
Thirty years ago the rivers of this watershed were polluted by industrial and residential discharges. The Nashua's restoration has been a model of how communities can recover a natural resource.
The facility is operated as a fully automated run of river project. At times of non-generation, the project is licensed to release an outflow equal to an instantaneous minimum of 207 cfs which is .50 cfs for the 414 square mile drainage are above the project site. When inflows fall below 207 cfs, inflow is equal to outflow.
Construction of the Jackson Mills Dam was completed in 1920. The dam is designed as a gravity-type stone masonry spillway , with a concrete cap and a concrete extension and concrete-faced stone gravity-type abutments. The height of the dam is 33 feet and the length is 180 feet. The crest elevation is 115.6 feet and the project is run with one-foot flashboards for a total hydraulic elevation of 116.6 feet.
A semi-Kaplan Turbelec turbine is installed in the powerhouse.The generating unit consists of one singe-regulated propeller-type turbine. The installed capacity of the unit is 1,100 kW.
Public Comment - We encourage public comments on this application. Specifically, we are interested in knowing whether you think this project meets our LIHI criteria. Review the program and criteria in greater detail and then review the Project’s application. Comments that are directly tied to specific LIHI criteria (flows, water quality, fish passage, etc) will be most helpful, but all comments will be considered. Comments may be submitted to the Institute by e-mail (preferred) at with "Jackson Mills Hydropower Project comments" in the subject line; by fax at (206) – 984-3086; or by mail addressed to LIHI, 34 Providence Street, Portland, ME, 04103. Comments must be received at the Institute on or before 5 pm Eastern time on March 31, 2010 to be considered. All comments will be posted to the web site and the applicant will have an opportunity to respond. Any response will also be posted