Winnicut River Watershed: The Thompson Brook Fish Passage Project

The Problem

With the discovery of young of the year brook trout in Thompson Brook in the summer of 2009, GBTU was given a tremendous opportunity to make a difference in cold water fisheries in Southeast NH. With the removal of the Winnicut Dam, a head of tide dam built back in the 1950s, the Winnicut River became the first free flowing major tributary of the Great Bay Estuary. There have been mills and dams inhibiting fish passage on the Winnicut since the 1660s. For the first time in 350 years diadromous species like Rainbow Smelt, shad, river herring (Alewives and Blueback), American eels and yes, brook trout, will have access to some of the 37 miles of riverine habitat that the Winnicut watershed offers. Not all of that water is accessible, however. Road crossing culverts prevent fish passage at many locations in the watershed. An extensive study, published just after the Winnicut Dam removal, by the New Hampshire chapter of The Nature Conservancy (TNC) showed that there were 11 key road crossings that impeded fish passage. One of those culvert crossings is at the lower portion of Thompson Brook, not far from its confluence with the main stem of the Winnicut River, and only a mile above the dam removal site at the head of tide. This blockage to fish passage is the closest to the head of tide listed of the 11 key impediments listed in the TNC report.

The Thompson Brook culvert, (culvert 2 in the TNC report), which crosses at Winnicut Road in Greenland, is a six foot wide corrugated round pipe culvert, installed over 35 years ago. The culvert is perched several inches on its downstream side, and in normal flows is very shallow and does not contain any river rocks to slow the flow within its 38 foot length. The culvert also significantly narrows the normal width of the stream from what would normally be fifteen to twenty-five feet wide to only six. This narrowing and the perching has lead to significant focusing of flow at its downstream exit, and created a large scour hole with poor stream bottom substrate. In short, this culvert completely disrupts stream continuity, and thus severely limits upstream access to the 1.7 miles of the predominately wooded Thompson Brook stretch. This area would be important habitat for eels and currently supports the wild brook trout found there. Without access to the watershed, this population of wild brook trout will not thrive due to the limited habitat and food necessary for the normal growth and lifecycle.

The Thompson Brook Culvert Outflow

The Solution

To solve this fish passage problem this culvert must be replaced with a structure that restores the connectivity to this section of the brook. New stream crossing regulations and standards are now in place in New Hampshire that allow for the normal bankfull width of streams to be restored as well as additional room for riparian connectivity as well. These regulations also specify that if more than an acre of wetland is upstream of a crossing that any new stream crossing structure must have a professional engineer stamp to ensure proper design and safety concerns in case of high water conditions. As a rough estimate, this 6 foot diameter culvert will, when redesigned, have to accommodate a 15 to 25 foot wide stream. This span would likely require more than another corrugated culvert as its replacement. Even a concrete box culvert might not be enough. This type of engineering and construction can be expensive!

During the grant application preparation, letters of support were given by the town of Greenland, the Greenland Conservation Commission, the Winnicut Watershed Coalition, the Piscataqua Region Estuaries Partnership, both of the culvert abutters, NH Fish & Game Department, and NH DOT! Dr. Thomas Ballestero, of the UNH Stream & Watershed Restoration Institute, has agreed to work on the project as its engineer and has also promised an in-kind match of $5000 in physical monitoring needed for the project. There are a lot of organizations and people that want to see this project go forward.

The Project

GBTU members met with NH F&G biologists, stream restoration specialists, and the TU National New England Regional Culvert Director early in December 2010. The result of that meeting was a commitment for GBTU to pursue grant money to get the engineering, permitting and eventual fish passage restoration started. As of February 7, 2011 GBTU has applied for two grants, either of which would allow the design work to begin and result in a professionally stamped crossing design with permitting completed by the end of the grant term of roughly one year. After that construction of the new crossing would need to be tackled, with estimated cost in the $200,000 range.

This commitment would also include supporting the monitoring of the fish before and after fish passage construction, restoring the riparian zone in the area of construction, as well as restoring the stream bed. GBTU will be applying for more grants and developing relationships with several state agencies including NH DES, NH DOT and of course NH F&G, during this process. All of these federal grants require a non-federal match which is usually a 1:1 match. This match does not have to be cash, although it can be. Work applied toward the project, both professional and volunteer can be donated and used as what is called "in-kind" match. Currently an hour of your volunteer, non-professional labor is worth about $20.85. Professionals can apply their usual rates for services toward this match as well. Equipment usage and donations can also be applied. Utilizing in-kind match large grants can be realized.

Call to Action

In our two prior surveys, it was clear that stream restoration and land conservation were the two highest priorities of our membership. However, outside of river cleanups and occasional donations to land conservation and dam removals, GBTU members have had little opportunity to participate in real stream restoration projects. It appears that is about to change.

In anticipation of one of our grant applications meeting with success, we will need to raise funds to pay for PIT tags and PIT tag detectors to monitor fish as they utilize the watershed, hopefully, down to the and including the tidal waters of the Great Bay Estuary. We will also eventually need to do some riparian work at the new crossing site which will require materials and manpower. We will also need a core group of dedicated volunteers to help align new partners in this project and capture additional in-kind match for the larger grants needed to actually build the new crossing. In short, we need you!

If you would be able to give some volunteer time, please sign up on one of the lists passed around at the chapter meetings or contact the GBTU Winnicut Watershed Coordinator, Joe Conklin (flydudeme@yahoo.com). If you cannot volunteer for whatever reason, please donate some money to the cause by going to the Thompson Brook Project PayPal Donation button below. You do not need to have a PayPal account to donate. All funds donated will be used on the Thompson Brook Project, and be utilized as a match for one of our grants. Don't like to do it online? Send us a check instead. If you donate $25 it will actually mean the project will see at least $50, $50 given means at least $100 for the brook trout of Thompson Brook, and so on. Every hour of volunteer time you give, whether helping Joe align partners in the project or planting trees and shrubs along the brook, translates into $20.85 of in-kind match and at least $41.70 toward on the ground restoration work. If only 5 members give 4 hours that translates into $417 of in-kind match which really means at least $834 toward the project.

The Big Picture

Restoring fish passage and habitat for the fish that would utilize Thompson Brook is a small but important first step in reversing the negative impact we have had on our region's waterways over the past several hundred years. Little by little projects like this amount to restoring a brook, which improves a river, which enriches a watershed. Healthy vigorous watersheds feeding Great Bay help to restore the estuary. Restoring the estuary benefits everyone for generations to come. It doesn't take much if we all give just a little. Let's all be a big part of the solution!

Donate to the Thompson Brook Project