Ammonoosuc River Assessment

One of the most beautiful rivers and treasured trout streams in New Hampshire, the Ammonoosuc rises at Lake of the Clouds on the shoulder of Mount Washington, and flows 60 miles through seven towns to its confluence with the Connecticut River in Woodsville.

The Ammonoosuc is recognized through the state’s Rivers Management and Protection Program. Its river towns (Carroll, Landaff, Bethlehem, Littleton, Lisbon, Bath, and Haverhill) have appointed citizens to the Ammonoosuc River Local Advisory Committee.

The project: To assist these towns and the Local Advisory Committee in understanding the river, the Connecticut River Joint Commissions worked with Dr. John Field of Field Geology Services to conduct a geomorphic assessment. This scientific study searched for riverbanks threatened by erosion, causes of channel instability, and places where floodplain conservation or riverbank restoration could lead to a healthier river.

Dr. Field and his staff walked the entire length of the river with a hand-held computer, noting bank height, erosion, presence of riprap, channel migration evidence, riparian buffer condition, invasive plants, and much more. This information was used to create maps of erosion hazards for each of the seven towns through which the river flows.

Study results: “It’s clear that most of the Ammonoosuc River offers excellent habitat and is in beautiful condition, with little severe erosion,” reports Dr. Field. “The worst flooding and erosion problems,” he continued, “are where the river valley suddenly widens or narrows, where tributaries enter, and especially where the channel has been artificially straightened.” By studying old maps and comparing them to valley shape, he has discovered places where people actually moved the river in the late 1800s and early 1900s. Examples are against the hillside east of the Littleton meadow and also between Salmon Hole and Lisbon village.

Such straightening, for log drives, to “get the river out of the way” of the railroad, or for other now-forgotten reasons, can have expensive consequences today. One effect is the erosion at the Lisbon Middle School soccer field, easily visible from Route 302.

Public outreach and floodplain conservation: North Country Council and the Ammonoosuc River Local Advisory Committee have helped their towns in using the study results and maps as they develop a river corridor management plan to guide future development. The Ammonoosuc Conservation Trust, a partner in the project, worked with interested landowners to consider conservation in places that could help ensure a stable river with high quality habitat.

Maps, Reports and Publications
Project Summary – start here to learn more about this project
Ammonoosuc River Corridor Planning Guide (large file size – 5.91 MB)- learn more details about restoration techniques and priority restoration sites

Field Geology Services presented the study results to local officials in each of the riverfront towns – the slideshows from each town are posted here. (Please note the large file sizes of these PDF slideshows.)
Carroll (4.45 MB)
Bethlehem (4.74 MB)
Littleton (5.38 MB)
Lisbon (6.76 MB)
Landaff (5.86 MB)
Bath (5.22 MB)
Haverhill (5.54 MB)

Final Technical Report – (file size is 2.31 MB) – appendices are available upon request from CRJC

Support for this project came from the Upper Connecticut River Mitigation and Enhancement Fund of the New Hampshire Charitable Foundation and from NH DES for Watershed Assistance for High Quality Waters.

Contact CRJC

Connecticut River Joint Commissions
10 Water Street, Suite 225
Lebanon, NH 03766
Phone: (603) 727-9484

Email: contact@crjc.org
- or - pcrocker@uvlsrpc.org