Issue Profile
Regulation of Dams

Contact: (207) 287-7688


Through Maine's history, its waterways have been home to thousands of dams. The earliest dams provided water power for sawmills and grist mills. Later came dams to run tanneries and textile mills, to control log drives and to power pulp and paper mills. In the last century, massive new dams were built to generate electricity, to regulate river flows, and to hold drinking water supplies.

Today, many of these dams are gone, victims of floods, changing economics, and neglect. But many dams remain, having become an integral part of our landscape and our society.

State policy-makers and local land owners have long been concerned with how these dams have been maintained and operated. Various laws have been passed over the years to regulate dams in one way or another. These laws have dealt with issues of registration, abandonment, water level and flow control, dam safety, and permitting of construction and repair activities.

Several significant changes have been made to these laws by recent Maine Legislatures. This Issue Profile explains how dams are regulated and provides references for further information.

Do dams have to be registered?

No. As of October 13, 1993, dams do not need to be registered with the DEP.

Can dams still be abandoned?

No. Under previous laws, abandonment was linked to non-registration; if an owner failed to properly register a dam, then the dam was deemed abandoned, and ownership transferred to the State. Because dams no longer need to be registered, they can no longer be legally abandoned.

All of the dams previously abandoned to the State have been awarded by DEP to new owners.

What happens if an owner no longer wants a dam?

Effective July 4, 1996, a dam owner may petition DEP for release from dam ownership or water level maintenance. The owner must then consult with shorefront property owners, town and Indian officials, and others to see if anyone wants to take ownership of the dam.

If no new owner is found, ownership may be assumed by one of several state agencies based on an assessment of the public value of the dam. Otherwise, DEP is required to order the dam owner to release the water from the dam.

Nothing prevents a dam owner from requesting compensation for the dam and associated water rights. However if a request for compensation prevents the transfer of the dam to a willing new owner, the current owner is not entitled to receive a water release order.

Doesn't the release of water from a dam harm the environment?

It may impact existing surroundings. However, state law essentially concludes that if no one who has an interest in the public and private resources affected by a dam is willing to own it, then the dam should no longer be operated to hold back water. The affected environment will then revert to its natural condition.

Can water levels and flows be regulated?

In most cases, levels and flows can be regulated; these include federally "grandfathered" hydro dams which, prior to July 4,1996, had been exempt from all state and federal regulation,.

Upon petition, DEP will hold a public hearing and issue an order establishing a water level regime and minimum flow requirement for the impounded body of water. (Municipalities may assume this authority from DEP by enacting a local water level control ordinance.)

In setting water levels and flows, DEP will evaluate impacts on public access and safety, fish and wildlife habitat, water quality, erosion, public and private water supplies, and power generation.

Dams that are exempt from the water level petition process include: hydropower dams subject to the jurisdiction of the Federal Energy Regulatory Commission; dams on boundary waters regulated by the International Joint Commission; and dams otherwise regulated under State law (such as the dams within the Cobbossee Watershed District).

More information on the petition process is available in the DEP publication "Regulation of Water Levels and Minimum Flows."

Do dams have to be maintained by their owners?

There is no law on the books requiring that a dam be maintained in good condition. Obviously, if a water level order or permit has been issued, it will be necessary to maintain the dam so as to comply with the permit or order. Also, MEMA can require that a dam be maintained or operated in a certain way if necessary to protect public safety. Otherwise, a dam can fall into disuse and disrepair until it either breached or is rebuilt by the owner. A private owner may be liable, however, for property damage or loss of life due to dam failure. (NOTE: Effective July 4, 1996, government agencies and municipalities are exempt from liability under the Maine Tort Claims Act from any claim for damages resulting from the construction, ownership, maintenance or use of dams.)

What about dam safety?

In 1989, the Legislature enacted a dam safety statute which is administered by the Maine Emergency Management Agency. This law focuses on identifying and regulating those dams posing a risk of loss of life or substantial property damage in the event of failure.

Questions about dam safety should be directed to MEMA at 72 State House Station, Augusta, ME 04333, (207) 624-4400.

Are there other laws regulating dams in Maine?

Yes. Construction or repair of a dam may be subject to regulation under one of several other state laws. These include: the Natural Resources Protection Act (for non-hydropower dams); the Maine Waterway Development and Conservation Act (for hydropower dams); and the Land Use Regulation Law (for dams in unorganized territories).

What activities at non-hydropower dams need a permit?

Generally, the construction, repair or alteration of a non-hydropower dam, as well as any associated dredging, draining, filling or soil disturbance, that occurs in, on, over or adjacent to a "protected natural resource" needs a permit. Protected natural resources include rivers, streams, brooks, great ponds, coastal wetlands, certain freshwater wetlands, and areas of significant wildlife habitat.

Maintenance and repair of less than 50 % of existing non-hydropower dams is exempt from permitting provided that certain standards are followed. These standards require that proper erosion control measures are taken, that the repair does not block fish passage, and that there is no additional intrusion into the water body.

More information on this permitting process is available in DEP publications on the "Natural Resources Protection Act."

What activities at a hydropower dam need a permit?

A hydropower project is any dam and associated structures that uses the flow of water to generate electrical or mechanical power or that stores and releases water to benefit power generation at downstream dams.

A permit is needed for the construction or reconstruction of a hydropower project, or for the structural alteration of a project in ways that change water levels or flows above or below the dam.

Examples of activities requiring a permit include: the building of a new power generating or storage dam; the rebuilding of a dam that once generated power; the addition or alteration of flashboards that changes water levels above the dam; and the installation of additional or enlarged turbines that changes flows below the dam.

Normal maintenance and repair of existing and operating hydropower dams is exempt from permitting if the activity does not involve dredging or filling in a waterway and does not diminish water quality.

DEP is the permitting agency for hydropower activities in incorporated municipalities, while activities in unorganized territories are permitted by the Land Use Regulation Commission.

More information on this permitting process is available in the DEP publication "Regulation of Hydropower in Maine."

How else are hydropower dams regulated?

Most hydropower dams are subject to federal regulation. Licenses are issued for water power projects for up to 50 years; at expiration, a dam may be relicensed or taken over by the federal government. Exemptions are issued in perpetuity for the development of small-scale projects using an existing dam or natural water feature.

All projects are subject to DEP terms and conditions designed to ensure that project operation will meet state water quality standards, including chemical and habitat standards as well as designated uses.

Where can I get more information?

For more information, contact the Bureau of Land Resources at the DEP office nearest you.

For dams in unorganized territories, call or write the Land Use Planning Commission, 22 State House Station, Augusta, ME 04333, (207) 287-3200.