Restoring Stream Connectivity in the Machias River Watershed: A Cooperative, Watershed-Based Focus Area Approach to Salmonid Restoration on a Landscape Level

Project SHARE (Salmon Habitat and River Enhancement) has organized aquatic habitat restoration work intended to improve Atlantic salmon and Eastern brook trout populations in the Downeast Maine. The overreaching goal of the restoration strategy is to improve aquatic and riparian habitat conditions on a watershed scale. The restoration thought process is based on correction of stream process rather than technical modifications of a site-specific reach to achieve short-term habitat improvements. Recognition that stream process begins in small headwater streams that influence the entire downstream water course provides the basis for a top-down approach. Therefore, the restoration strategy intends to identify and address multiple habitat threats at many relatively small restoration sites on a watershed scale. Working within the context of SHARE’s mission and authority, specific goals are to increase watershed connectivity (including fish passage), increase instream habitat complexity, decrease anthropogenic sedimentation inputs, and mitigate anthropogenic changes in water chemistry (pH, temperature). Identification of high priority sub-watersheds and threats assessment within selected focus areas allows limited resources to be focused in a manner that improves the potential for long-term success and benefit to the resource. It is generally recognized that dams and culverts can present barriers to both upstream and downstream fish passage. Less obvious disruptions of the continuum of stream ecological processes have not reached a similar level of mainstream awareness among land-use planners, regulators, and conservation groups. Road-stream crossings have been identified as a principle impact to stream connectivity and subsequently to salmon recovery in the Machias River watershed. Working cooperatively with landowners, state and federal agency partners, SHARE has replaced 100+ undersized round culverts with open bottom arch culverts and has decommissioned 10+ road crossings in the Machias River watershed. It is generally recognized that most of the dams on the Machias River were removed at the end of the log drive era. However, SHARE has documented the existence of 50+ historic dam sites in the Machias River drainage. In most cases the sites do not present impairment to fish passage. However, remnant structures and the reservoirs associated with the sites do present an anthropogenic impact to channel morphology that continues to affect hydrology, sediment transport and water temperature. We will present an overview of the Machias Watershed restoration strategy including: watershed prioritization, identified threats, symptoms of altered stream connectivity, and habitat restoration efforts to date.