River Ice in the Winnipesaukee

Public Notice sent out by email newsletter by the City Manager's Office.

Yesterday, the Franklin City Manager's Office produced and sent out an email newsletter. It discusses a potential threat of river ice and build up on the Stevens Mill Dam, a hydropower facility owned by Eagle Creek Renewables, who is now owned by Apollo Funds.

Our current understanding is that Franklin Fire Department Chief and Emergency Management Director Foss walked the area with the Dam Bureau Watershed Manager from NH Department of Environmental Services.

Mill City Park was first notified Sunday afternoon via a phone call from the City Manager. Upon receiving it, we called the whitewater park construction foreman from AJ Coleman Construction. Coleman Construction has been a phenomenal partner through this project. Within 1.5 hours (on a Sunday), the foreman was onsite looking for ways to help.

Some folks online have drawn parallels from the ice jam to our construction project. This is another demonstration of hate and/or division rather than knowledge and/or experience.

So let's break it down.

WHAT is exactly happening?

The concern expressed is that ice is getting pinned onto the Stevens Mill Dam. If enough ice was pressed against the dam, and it was large enough or it sat there long enough to freeze, the fear would be that the river could no longer flow downstream and it would "jump" its banks. This would result into flooding in downtown Franklin.

This has happened before at this location. In 2008, ice was pressed against the dam and pinned on the dam and the catwalk bridge that was suspended above the dam. This formed a wall of ice and flooded some nearby buildings. The catwalk bridge was damaged and removed in subsequent months, it no longer is installed.

WHEN?

Ice has been forming all winter. However, the newsletter went out yesterday. The City Manager called us yesterday. We don't know the date and time of the walk with NH DES Dam Bureau.

WHERE are we talking about?

The newsletter reference Stevens Mill Dam as the area of concern for potential flooding.

Whitewater park construction is happening upstream of Trestle View Park, essentially there are two "hot spots" of construction; one is under the Sanborn Bridge upstream (525 ft upstream of the Stevens Mill Dam) and another south of Mill City Park's parking lot (1,413.52 feet upstream of Stevens Mill Dam).

This round of construction is centered on two points. 525 feet upstream (or east) of the Stevens Mill Dam and 1,413.52 feet upstream.

WHY and HOW is it happening?

Some are speaking out about this as if it was an instantaneous issue, a result of a catastrophic mistake. When in reality this has been happening in front of our eyes all winter.

Ice dam and ice build up in the Winnipesaukee River (specifically the Lower Winni, the whitewater section from Cross Mill Road to Stevens Mill) happens when two conditions occur: low water and extreme cold.

The Lower Winni drops 80 feet per mile from Cross Mill Road to downtown. This is very steep. It is why the mills used to be in Franklin and it is why whitewater kayakers love Franklin. The gradient drop of the river plus normal river flows (minimum flow of the river is 250 cfs) keep ice build up at bay. This is a major reason for the January 1st release, even though it is cold the river flow and the river's force don't allow ice to form.

So why was the river below 250 cfs?

The second week in October is a dam maintenance window. It is when the Winnipesaukee River, from the big lake to the confluence with the Pemigewasset, is reduced below minimum flow to 50 cfs. It provides the opportunity for dam owners to do maintenance on their facility at a low water level.

2025 Lake Winnipesaukee Data

2026 Lake Winnipesaukee Data as of today.

NH DES Dam Bureau maintains specific data on Lake Winnipesaukee. Their published graph for 2025 identifies the watershed has been in drought conditions since August. The lake finished 2025 about 0.75 feet lower than it should have been. The regions is still considered to be in a drought.

In October 2025, NH DES identified that they would hold the 50 cfs flow for as long as they needed to with the goal of filling up Lake Winnipesaukee as quickly as they could, in hopes of controlling the lake level height per their plans and the referenced graphs.

Of course DES keeping the river at low flow was beneficial to the whitewater park construction. It was a lot less water to manage. So we weren't complaining.

About 44 days in to 2026 (February 13th), the lake level approached the planned height. It was around this point DES communicated the increase in river flow. The reason for raising the river flow is to try and hold the lake level height to the plan per the graph.

Whether you call this a traditional New Hampshire winter or an uncharacteristically cold winter, it doesn't matter. It has been cold. Cold enough for Mother Nature to create a lot of ice in the river corridor.

Put Simply.

It is not because of whitewater park construction. It is because of very cold temperatures and the river has been below minimum flow.