River Assessment & Restoration

Findings of Fluvial Geomorphic Assessments

A fluvial geomorphic assessment seeks a scientific understanding of how a river's watershed and human land use affect the river channel. Rivers are constantly adjusting to many changes, from dam building or breaching to road and railroad building and even deglaciation. Understanding how these changes alter the width, depth, and form of a river channel is essential for identifying potential problems in a river system and identifying long-term solutions for channel instability.

Fluvial Geomorphology Assessment of the Northern Connecticut River, VT & NH, 2004 

Bank Stabilization Implementation and Assessment of the Connecticut River near Colebrook and Groveton, NH, 2006

Fluvial Geomorphology Assessment of Northern Connecticut River Tributaries, 2006 (Mohawk & Upper Ammonoosuc Rivers)

River Assessments and Reports

Studies sponsored by CRJC with Field Geology Services, with support from the NH Department of Environmental Services, Upper Connecticut River Mitigation & Enhancement Fund, and National Oceanic & Atmospheric Administration

Connecticut & Lower Mohawk Rivers, Colebrook

Ammonoosuc River

Erosion Maps of Northern River Towns

The erosion maps posted here were created for CRJC by Dr. John Field of Field Geology Services, based on his 2004 assessment of 85 miles of the Connecticut River in northern New Hampshire and Vermont. Each town has received a large planning scale version of these maps, showing erosion and riverbank condition.

(Note: Mapping software is not necessary to view or print these maps, although Adobe Acrobat Reader must be installed on your computer.Download it for free.

Guide to maps (large file):
Causes and Management of Bank Erosion on the Upper Connecticut River

 

Vermont Erosion Maps

Canaan (northeast, north, central, south)
Lemington (
north, central, south)
Bloomfield (
north, central, south)
Brunswick (
north, central, south)
Maidstone (
north, south)
Guildhall (
north, south)
Lunenburg (
north, central, south

 

New Hampshire Erosion Maps

Pittsburg (central, south)
Clarksville (
north, central, south)
Stewartstown (
north, central, south)
Colebrook (
north, south)
Columbia (
north, central, south)
Stratford (
north, central, south)
Northumberland (
north, central, south)
Lancaster (
north, central, south)
Dalton (
north, south)

Fluvial Geomorphology Assessment of the Northern Connecticut River, Vermont and New Hampshire 
Field Geology Services, October, 2004

A fluvial geomorphic assessment of 85 miles of the northern Connecticut River between Murphy Dam in Pittsburg, NH downstream to Gilman Dam between Gilman, NH and Lunenburg, VT has identified the major natural and human factors controlling channel morphology and causing bank erosion.

Final Report
selected appendices
Phase 2 Cross-Sections of 18 Reaches
Options for Restoration at the Colebrook Industrial Park

Bank Stabilization Implementation and Assessment of the Connecticut River near Colebrook and Groveton, New Hampshire. Field Geology Services, 2006

Continuing efforts to address bank erosion problems along the Connecticut River have led to the permitting of a bioengineering project at the Colebrook Business Park, a detailed assessment of bank instability at the Northumberland Cemetery, and production of erosion hazard maps for each town in the study area.

Bank instability at the Northumberland Cemetery is related to: 1) the breaching of the Old Wyoming Dam 3.0 miles downstream of the cemetery; 2) the breaching of Nash Stream Bog Dam in the Upper Ammonoosuc watershed; and 3) the resulting sand bar development on the Connecticut River at the Upper Ammonoosuc River confluence.

Final Report
Phase 3 Survey Data
Hydraulic Modeling Results
Bioengineering Design Specifications, Colebrook Business Park
Conceptual Restoration Designs, Northumberland Cemetery

Fluvial Geomorphology Assessment of Northern Connecticut River Tributaries (Mohawk & Upper Ammonoosuc Rivers)
Field Geology Services, January 2006

A fluvial geomorphic assessment of the Mohawk and Upper Ammonoosuc Rivers, tributaries to the Connecticut River in northern New Hampshire, has identified the major natural and human factors controlling sediment delivery to the Connecticut River mainstem where bank erosion threatens the Colebrook Business Park (adjacent to the Mohawk River) and Northumberland Cemetery (adjacent to the Upper Ammonoosuc).

Final Report
selected appendices
Lower Mohawk River Conceptual Design Options 
Mill Brook Conceptual Design Options

Restoration of the lower Mohawk River alluvial fan was completed in the fall of 2009.

 

Mohawk River Stream Restoration

Restoration planning on the lower Mohawk River, near its confluence with the Connecticut River in Colebrook, has led to a project aimed at long-term resolution of erosion at the Colebrook Business Park. This erosion is caused by sediment deposited at the mouth of the Mohawk after the channel was artificially straightened decades ago. Restoring the alluvial fan on the lower Mohawk, using engineered log jams and diversions, will help capture gravel and other sediment from the river's upper watershed before it can enter the Connecticut. Other benefits include waterfowl and aquatic habitat restoration.