April 04, 2014
Late last year (December 19, 2013) I took a trip with Scott Craig, from the Maine Fisheries Resource Office, out to West Branch Brook in the Narraguagas river watershed. With plenty of snow on the ground, we ditched the truck and packed our survey gear in on sleds.
The uppermost portion of the Narraguagas River watershed, the Beddington Lake Hydrological Unit, is one of the highest priority watersheds for Atlantic salmon restoration in all of Downeast Maine. For the last two years, SHARE has been gearing up to address it’s restoration with the support of local landowners.
We’ve completed a road-crossing inventory of the entire Beddington Lake watershed with funding provided from the American Recovery and Reinvestment Act, and of all the sites identified, a culvert on the intersection between the 30-00-0 road and West Branch Brook looks to be the most significant project in the watershed. We set out with our gear to conduct a preconstruction survey of the site, helping us to assess what was currently there, and to determine what our final design will look like.
Based on the data we collected and observations made previously, it appears that the culvert is located on top of a remnant dam. Aside from making passage more difficult for the aquatic organisms that inhabitat that stretch of the river, the culvert affects the stream hydrology, resulting in increased water temperatures, diminished sediment and nutrient transport, and maintenance issues. At more than 8 feet deep, the plunge pool at this site is impressive to say the least…
Based on our survey, the culvert is set near the correct elevation. However, considering the size of the plunge pool and the presence of a sediment wedge upstream, the evidence indicates that the existing culvert is undersized. At high water events, the culvert acts like a firehose, scouring out the plunge pool downstream, and holding back water upstream, causing sediment to drop out of the water column.
By replacing the culvert at this site with a structure that conforms to stream simulation design standards, we’ll open access to nearly 9 miles of contiguous upstream habitat, and 170 units of habitat. Aside from Atlantic salmon, these efforts will benefit Brook trout, Sea Lamprey, American eel, Alewife, and Blueback herring populations.
Funding was provided by a grant from the Association of US Delegates to the Gulf of Maine Council on the Marine Environment (GOMC #13-10, with assistance provided by Scott Craig of the Maine Fisheries Resource Office.