Restoring Aquatic Connections in Maine

Water is not the only thing that flows through Maine's rivers and streams - they are essential travel routes for many species. Even the smallest seeps that extend far from the nearest river can form a clear path for fully aquatic species, such as salamanders or brook trout. Species that can exit the water - like turtles and beavers - also use these routes as a means to move from A-to-B..

The movement of life through rivers and streams is essential to both aquatic and terrestrial ecosystem health. Migrating fish bring much needed nutrients and energy from deep, otherwise unreachable lakes, ponds, or oceans far upstream into wetlands, forests, and mountains. If a seed drops from a tree to the water below, it could catch a ride and be planted miles downstream - an efficient system, until a poorly designed culvert is plunked mid-channel.

Aquatic connectivity has been severed across Maine. However, Stream Smart practices are being applied at projects throughout the state and miles of river and stream habitat are beginning to re-open. Check out some great examples below of how far upstream Maine has come in the era of restoring stream connectivity!

The undersized, perched culvert was removed and replaced with a new crossing, meeting Stream Smart design standards. The 10.5-foot-wide, concrete, open-bottom arch culvert allows for uninterrupted stream flow, restoration of the natural stream channel, better flood resistance, improved infrastructure, and access to over two miles of upstream habitat for aquatic wildlife.

The majority of this project ($200,000) was funded by the Maine Municipal Stream Crossing Upgrade Grant Program ($125,000). Maine Outdoor Heritage Fund (MOHF) provided a $35,000 grant, and The Maine Chapter of The Nature Conservancy (TNC) donated $19,800. The town of Dixmont contributed $11,900 cash and nearly $10,000 in in-kind services and equipment. Merry Gallagher, MDIFW Native Fish Conservation Biologist, and Alex Abbot, Stream Restoration Specialist, volunteered their services to assist the town in seeing this project to completion. The Dixmont Conservation Commission oversaw the project, volunteered many hours of time and expertise, and persevered for five years to finally make the project happen. Dirigo Bridge Company of Madison built and installed the new crossing and provided valuable expertise and support to the town.

Rather than rebuild fish passage for the Veazie and Great Works dams, both were removed in their entirety and completely restored connectivity for aquatic species in the Lower Penobscot River. At the same time, negotiated changes changes were made at upstream dams that boosted power generating capacity and improved fish passage.

Howland Dam was not removed but received a fish passage alternative. Traditional fishways are artificial lifts and ladders - this one is essentially a naturalized stream channel constructed around the dam. It features a natural substrate bottom with multiple riffles and pools throughout, allowing for resting places as fish move their way upstream.

The benefits of these restoration efforts were almost immediately realized. The abundance of alewives and blueback herring passing through dramatically increased from a few thousand to over six million. This has major ecosystem benefits, such as increased nutrient flow, a steady food source for predator species, and providing cover for migrating Atlantic salmon from predators. Furthermore, the owner of Milford Dam, which sits upstream of Great Works Dam, installed a fish lift in 2014. These collective efforts opened hundreds of miles of habitat and has transformed the Penobscot River and its tributaries.

An important note about connectivity is that it may also come with risks and that strategic approaches may be necessary to handle unintended consequences. For example, removing dams and other barriers may unintentionally allow invasive species such as Northern Pike to spread. Anticipating and managing these effects is essential to native fish restoration.

The following map provides more examples of projects that are restoring aquatic connectivity across the state. These are locations that have been funded by the Municipal Stream Crossing Upgrade Grant program administered by Maine Department of Environmental Protection (2014-2022) and Maine Department of Transportation (2023-current) which focus primarily on culverts and bridges.

If you are interested in contacting Stream Smart to attend a workshop or create a project in your town, please email conserve@maineaudubon.org or call 207-781-2330 ext. 219.

Beginning with Habitat equips Maine communities, landowners, and conservation partners with information and tools to protect, restore, and connect important habitats and ecosystems in a changing climate. Housed within the Maine Department of Inland Fisheries and Wildlife, Beginning with Habitat staff work with species experts, ecologists, and conservation partners to translate biodiversity information into conservation action at both a local and statewide scale.

The Maine Stream Habitat Viewer is an interactive map viewer on the Beginning with Habitat website. This map viewer allows you to view wetlands, road crossings, aquatic barriers, and habitat ranges of priority aquatic species in Maine. You can download a custom map for a designated location by selecting layers of interest. This is a free resource to the public that allows you to stay informed about aquatic habitat data near you.  Click this link to open the map viewer.