C. In-stream Restoration for Salmonid Habitat

Morning Session – 8:30AM-10:30AM
Washington/York Room (2nd floor)

Session Co-Chairs:

Maine is home to the only remaining populations of wild Atlantic salmon (Salmo salar) in the United States as well as the most extensive distribution and abundance of wild brook trout (Salvelinus fontinalis). These coldwater fish populations face a large suite of threats to survival, many of which are compounded by the impacts of climate change. Sufficient access to suitable habitat is necessary for the long-term sustainability of wild populations. Restoration efforts have been focused on restoring habitat connectivity past dams, culverts, and other restrictions. Once longitudinal connectivity is restored, however, focus can shift to improving habitat quality, including in-stream flow conditions, water quality and temperature, lateral connectivity with flood plains, and habitat complexity. In-stream restoration work builds resiliency, providing the capacity for stream habitats to withstand changing environmental conditions including drought and extreme temperatures. Assessing past land use history helps identify threats and impacts to in-stream habitats and informs restoration priorities to ensure that there is enough suitable habitat for coldwater salmonids in the foreseeable future for sustainable populations. This session will focus on the need for ecosystem-based assessment of habitat suitability and recent in-stream restoration projects.

Session Overview

Session Abstracts

Presenters are indicated in bold font.

Habitat Restoration in the Machias River Watershed – The effects of the log drive era

A pdf of this presentation is available. Please contact Steve Koenig with any questions.

Steven D. Koenig
Project SHARE

SHARE has been engaged in on-the-ground habitat restoration in the Downeast Rivers for two decades. In developing the restoration program, we established collaborations, identified threats, and acquired the training needed to implement restoration actions. Over the years we have been documenting the land use history and connecting it to what we see as the condition of the Machias River. Sources have included: direct observations on the river, discussions with the “older” generation, historic maps, historical references, plus a trove of information archived in the Special Collections at the University of Maine-Orono. Today we will go back in time and link the settlement of Machias and the log-drive era to the current state of the river and the threat assessment for Atlantic salmon recovery.

Headwater Stream Diagnostics for Watershed Management Decision-Making in Maine’s Deglaciated Landscape

Sean M.C. Smith1,2, Neil Thompson3, Cade King4, Hayden Libby5, Morgan Oehler6, Angie Casella4, Sam Roberts4, Bea Van Dam2
1. Senator George J. Mitchell Center for Sustainability Solutions
2. School of Earth and Climate Sciences, University of Maine
3. University of Maine Fort Kent
4. Ecology and Environmental Sciences Program, University of Maine
5. Dept. of Civil and Environmental Engineering, University of Maine
6. Dept. of Civil and Environmental Engineering, Virginia Tech

Substantial attention has been given to development and implementation of protocols for assessing fluvial systems and detection of changes to stream conditions over time. Headwater stream conditions influencing cold water fisheries habitat and water quality in rural Maine have not been as extensively evaluated as other locations where stream assessment and classification protocols have been developed. More knowledge and information is necessary to consistently diagnose headwater stream conditions in the region to predict the implications of past, present, and future disturbances from civil infrastructure, large-scale forest harvest activities, and climate change. Questions about the effects of watershed disturbances on stream conditions have inspired recent efforts to quantify and interpret headwater (1st to 3rd order) tributary conditions in Maine. Our ongoing research focuses on the Smith Brook drainage network in the Fish River watershed of Aroostook County with interest in customization of approaches to diagnose stream conditions, detect changes, identify drivers of change, and guide watershed management decisions. The recent project has included participation of six students working on watershed mapping, stream reference site measurements, watershed modeling, and data analysis. Outcomes are arranged to evaluate applications of existing stream classification systems in the region, customize diagnostic data acquisition and analyses, and support stakeholder engaged management decision-making processes. This presentation will summarize our preliminary observations and results, and identify data and knowledge gaps that currently constrain diagnoses of stream channel conditions, assessments of dynamics in response to watershed and climate changes, and strategies for stream restoration.

A Stream Habitat Assessment Pilot Study on the West Branch of the Sheepscot River

A pdf of this presentation is available. Please contact Bill Bennett with any questions.

Bill Bennett1, Jen Noll2, Melissa Cote3
1. US Fish and Wildlife Service
2. Department of Marine Resources
3. Midcoast Conservancy

The Sheepscot River Watershed is home to twelve species of native sea-run fish including the southernmost genetically unique population of returning wild Atlantic salmon (Salmo salar) in the United States. The removal of Coopers Mill Dam in 2018 and partial dam removal at Head Tide Dam in 2019 restored fish passage to much of the watershed and Atlantic salmon’s native rearing and spawning habitat. With these barriers gone, an increased understanding of on-the-ground habitat conditions and factors impacting watershed processes is needed to develop a strategic approach that restores the watershed in a holistic manner for these imperiled species. To address this, a pilot project is being undertaken in the West Branch Sheepscot, major tributary of the Sheepscot River, to assess habitat quality and describe factors limiting Atlantic salmon populations. Geospatial analysis was conducted of this subwatershed to test different methods to classify and map characteristics that affect stream and floodplain habitat. Following this spatial analysis, 12 reaches were assessed to groundtruth modeled conditions and identify how a reach deviates from reference conditions. Our initial assessment found that water temperature and depth were the greatest limiting abiotic factors to salmonid abundance in these reaches. Factors likely contributing to these conditions include droughts resulting from climate change, and historic anthropogenic modification of the river, including the reduction of wood load, increased stream width, and reduction of pool depth and frequency.

Narraguagus River Process-Based Restoration Project

A pdf of this presentation is available. Please contact Mark Jordon with any questions.

Mark Jordan1,2, Christopher Federico3, William Bennett4
1. Jordan Environmental Engineering
2. University of Maine, Earth and Climate Sciences
3. Project SHARE
4. US Fish & Wildlife Services

From the time of early European settlement in Maine, through the early twentieth century, the Narraguagus River watershed experienced intensive timber harvests and river modifications that resulted in a significant loss of Atlantic salmon habitat. The combination of the removal of boulders and large wood from the river, and the use of splash dams that released large torrents of water to facilitate log drives, resulted in river segments that are over-widened and heavily armored. These river segments lack quality habitat due to 1) a lack of depth and flow complexity, 2) elevated water temperatures caused by a combination of a large width to depth ratio, insufficient shading, and reduced connections to hyporheic flow, and 3) increased risk of predation resulting from a lack of plant cover. This talk will outline how Project SHARE, through a multi-disciplinary collaborative effort, undertook a demonstration river restoration project. The presentation team will address the determination of location, design, construction and resulting impact of the intervention. The project included three large engineered logjams, constructed floodplains, numerous combined boulder/log clusters and the re-connection of several floodplain channels to the main channel. This site was selected based upon temperature data indicating cold-water inputs within the area, local disconnected off-channel habitat, and a relatively high river gradient. The design closely follows the principles of process-based river restoration and included several multi-disciplinary workshops. The construction in 2022 was accomplished using all local, natural materials and a local contractor. The project has resulted in improved aquatic habitat and floodplain connectivity.