For Messalonskee Stream Hydro, pursuing LIHI certification was initially about market access, but the process unexpectedly helped reshape how the project’s four hydropower sites engaged with their rivers, ultimately leveraging certification to transform compliance into lasting environmental practices.

Messalonskee Stream Hydro, LLC, is a private hydropower company that operates four sites along the Messalonskee Stream: Union Gas (1.5 MW), Rice Rips (1.6 MW), Oakland (2.8 MW), and Automatic (0.8 MW). All four projects operate as run-of-river, particularly when inflow from the upstream Messalonskee Lake (Snow Pond) storage dam is sufficient.

In 2010, the company took the first steps toward earning a Low Impact Hydropower Certification, with the primary goals of qualifying for the Massachusetts Renewable Portfolio Standard (RPS) and selling Renewable Energy Credits (RECs).

However, as the process progressed, a critical environmental consideration emerged that Messalonskee Stream Hydro would need to address to meet certification requirements.

Bridging the Gap Between Operations and Ecology

While water quality was poor in the past due to discharges from former mills, septic systems, and agricultural and urban runoff, the projects were in compliance with regulatory requirements—meeting minimum flows, water quality, cultural resources, and recreation requirements.

Still, LIHI’s assessment identified a significant need to enhance fish passage across sites.

In the densely populated region of Waterville, Maine, the Messalonskee Stream passes through residential neighborhoods, agricultural pastures, and urban areas, as well as a narrow gorge, before converging with the Kennebec River at Petty’s Rips.

The stream and river are home to a range of migratory and resident fish species and to diverse aquatic invertebrates that are unique to the region's water systems. The river corridor is also an important local resource, providing trails and fishing access for residents and students who attend the local college.

Other dams on the Kennebec and Sebasticook Rivers (another tributary) had already installed eel passage facilities, and it was increasingly a recommended practice by resource agencies. These combined pressures made it clear that a more proactive, coordinated approach would be needed to address fish passage across projects.

Adopting Adaptive Management and Infrastructure Improvements

Messalonskee Stream Hydro worked alongside resource agencies to facilitate safe passage for American eels. LIHI served as an advisor, cooperatively working with Messalonskee and the agencies to craft a solution that worked for all parties.

Upstream eel ladders were designed and installed at all four projects. Monitoring confirmed they were working — and the agencies took notice.

“I commend you on designing and installing a passage at this very difficult site…I am pleased with the number of eels that passed upstream…and the passage efficiency,” said a representative of the Maine Department of Marine Resources regarding the Oakland installation.

Downstream passage was initially managed by trapping and trucking eels, but this approach proved only partially successful, prompting the implementation of nighttime shutdowns in 2020. Though the temporary losses in generation and revenue were unavoidable, Messalonskee Stream Hydro agreed to shut down operations at all four projects from 6 pm to 2 am from September 1 through October 30. Project infrastructure at Union Gas was also modified to provide a downstream passage route from Messalonskee Stream into the Kennebec River.

“Engaging with LIHI can be a positive experience that results in a win-win for all parties involved. It is always worth speaking with them to evaluate your project. While operations may be impacted, working with LIHI can ensure that a project owner can still focus on maximizing generation while also being a steward for the river,” stated a representative from Messalonskee Stream Hydro.

As a result, the interventions yielded safe, timely, and effective passage for American eels.

Since Messalonskee Stream Hydro's initial application, its projects have been successfully certified and recertified multiple times, demonstrating the project's commitment to compliance and continued environmental performance.

Lessons from Messalonskee Stream

This case highlights how LIHI certification can function as more than a market mechanism. Instead, its criteria can help drive meaningful ecological outcomes. By fostering collaboration and adaptive management, the certification process enables hydropower operators to move beyond baseline compliance toward long-term river stewardship.

At the beginning of the certification process, Messalonskee Stream Hydro merely wanted to gain market access. In turn, the project helped improve fish passage, strengthened relationships with resource agencies, and developed a more resilient approach to operating within a complex river system.