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One Highway, Two Culverts, Four Organizations and Lots of Baby Brook Trout

Updated: Jun 6, 2022

The Restoration of the Ballard Brook Culverts By: Linden Rayton

As early as 2006, New Hampshire began investigating the sustainability of its culverts, also known as stream crossings, under the multi-agency New Hampshire Stream Crossing Initiative campaign. Many volunteers traversed our state, surveying stream crossings and grading them for ease of wildlife passage and flood control. This has resulted in the spectacular online Aquatic Restoration Mapper (ARM), which highlights stream crossings in need of repair, as well as displaying lots of other interesting stream crossing data from around the state.

A culvert can need repair for many reasons. The two major ones are restoring wildlife passage and allowing good water flow. Many of our decades-old pipe culverts are not good at allowing water to flow naturally, which has resulted in water pooling at either end of culverts. When large flood waters move through, these pools, plus the narrow pipe, make for a destructive combination which can result in multi-thousand dollar road repairs. Just as water can’t travel naturally though these pipes, neither can fish. Many species of fish spawn in the cold, clear upper reaches of watershed tributaries. Here in the Warner River area, one of those fish is the beautiful and prized native brook trout (Salvelinus fontinalis), which so happens to be our state freshwater fish. Brook trout likely used to occupy every watershed in New Hampshire, and were common from eastern Canada to Georgia. Now they are only present in about half the watersheds of New Hampshire, and are considered a species of “Special Concern” by the state because of their value as a game fish and their need for clean, healthy waterways- so their presence is an excellent indicator of ecosystem health. Brook trout can only jump about 15”. If the difference between a culvert ledge and the stream below (known as the “outlet perch”) is greater than that, brook trout are unable to pass through the culvert.

A casual glance at the ARM shows that many of the culverts within our Warner River Local Advisory Committee oversight are both in need of repair, and a high priority of the state. This is because of the population of wild native brook trout in several tributaries of the Warner River. One of these is Bartlett Brook, which passes under I-89 through two culverts which were built 50+ years ago and never designed to naturally pass the full water’s worth of Bartlett Brook. Over the years, this had resulted in an outlet perch on each culvert that was too high for brook trout and other species.

The DOT alerted us that they were going to begin work on repairing these culverts in summer 2020. Because of the permit they had, they were required to work with NH Fish & Game (F&G) to restore the culvert to full water-and-fish passage, a partnership that ended up involving multiple agencies and the NH F&G Fish Habitat Program, a fish habitat restoration account funded by percentages of fishing license fees. The pictures in this article are taken from Fish & Game’s Facebook page, from a post on Aug. 25, 2020. (You can also view additional interesting photos within ARM by finding Bartlett Brook and clicking on the two culverts under I-89.) They show the incredible work that ended up transforming these culverts, the result of hard work on the parts of the DOT, F&G, Weaver Brothers Construction Company and noted restoration expert Tom Ballestero of the UNH Civil and Environmental Engineering Dept. (Thank you Tom- and Go Wildcats! Proud alum over here.)

By the time construction was finished in August, the brook flowed perfectly into the culverts and out again- no waterfalls anywhere. Several constructed weirs (small dams, in this case made of round boulders) led the stream in a fish “ramp” down away from the first culvert and then again through and past the second, and on toward the Warner River. And the fish noticed. As John Magee, Fish Habitat Program Manager, notes in his post, within only four hours of streamflow being restored, baby brook trout were observed ascending much of the downstream fish ramp! When F&G employees returned to survey the fish species upstream present two weeks later, they found not only brook trout but also blacknose dace, fallfish and white sucker! All had successfully navigated the new and improved ramp of the downstream culvert and were well on their way to accessing the cool and clear waters of upper Bartlett Brook.

These repaired culverts are a wonderful addition to our Designated River watershed. We are so grateful to the work of dedicated professionals like John Magee, Tom Ballestero, and all the other employees of F&G, DOT and the Weaver Brothers Construction Company who made this sustainable culvert possible. And we are happy that we, as the Warner River Local Advisory Committee, can be a small but important cog in these project types; reviewing permit applications carefully, urging environmental restoration and river health; cheering it on when it happens; and, for some of us, getting out to then go fish for some healthy adult brook trout, members of a population whose “neighborhood” just got a lot bigger.

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