Franklin Conservation District


River Corridor Mapping Method for the North River Watershed, Colrain

Through a recent Innovation Grant from the MA Executive Office of Energy and Environmental Affairs, the Franklin Conservation District (FCD) has been able to undertake an important project to benefit the Deerfield River watershed. FCD has partnered with Field Geology Services to develop a protocol to identify river areas most susceptible to erosion and apply it to the North River watershed in the Town of Colrain. This river corridor mapping will provide a cost-effective tool for towns, state and federal agencies to identify vulnerable locations at a municipal, parcel-level scale. Protecting those areas along the river where erosion is most likely to occur will improve ecological function, limit downstream flooding and sediment loading, and increase community resiliency to future climate change.

The North River, a tributary of the Deerfield River, suffered some of the worst damage from Tropical Storm Irene in 2011, including severe erosion of agricultural fields, streambanks, landslides, road washouts and damage to bridges. Severe bank erosion continues to threaten Colrain community wells and public wells for Shelburne and Buckland that are located in Colrain.

To place this storm in context, UMass researchers have estimated that sediment discharged from the Deerfield River in one day exceeded, at least 10 to 40 years’ worth of normal sediment discharge and accounted for approximately 40 percent of the total sediment discharge from the Connecticut River resulting from Irene.1  They also reported that Irene caused the most severe erosion of any flood in the historic record. They attribute this extreme erosion to the fact that at the time of the storm soils were saturated due to higher than normal rainfall. The researchers conclude that the potential for highly erosive storms is growing as wetter conditions increase due to climate change.2

Towns affected by Irene have worked to repair damages, but staff and financial resources of our small, rural towns are very limited. Communities would benefit from help to identify areas that are most susceptible to erosion in future events. They would also be helped by strategies and tools to protect and restore these locations.

The goal of this project is to develop and pilot an innovative river corridor mapping tool that will identify areas susceptible to erosion and channel migration and help prioritize river and floodplain restoration projects and river corridor protection opportunities. A key objective of the project is to develop a tool that can be applied in communities across the Commonwealth and beyond. It will also inform the development of a new paradigm for river restoration; namely, land conservation of erosion and flood-prone areas.

A great need exists for an efficient method for identifying the area along a river that is most susceptible to erosion due to long-term channel migration or sudden shifts in channel position resulting from log jams, ice jams, or catastrophic flooding. Federal, state, and local officials need such information to identify at-risk infrastructure, but existing methods are either too coarse for detailed planning or too time consuming and expensive to be of practical use for most towns experiencing frequent erosion-related damages to infrastructure. Protecting those areas along the river where erosion is most likely to occur over long time periods – decades to a century -- has the added benefit of improving ecological function, limiting downstream flooding and sediment loading, and increasing community resiliency to future climate change.

Field Geology Services will develop and test a method for delineating river corridors that will be of practical use to municipalities and will significantly reduce costs compared to current methods.  The focus area in the North River watershed will include reaches where erosion threatens public wells for Colrain, Shelburne and Buckland, areas of great concern for the communities and FCD.

The North River represents an excellent location to conduct a pilot study for this method because the significant erosion damages experienced during Tropical Storm Irene in 2011 led to several studies attempting to identify at-risk areas and potential restoration projects to reduce future damage. The data collected during these studies will provide a means for checking this approach for delineating corridors before extending the work, as part of future projects, to the greater Deerfield watershed and beyond.

Field is delineating river corridors by using remote sensing data (e.g., aerial photographs, topographic maps, and LiDAR) to determine the outer limits of river migration in the past as evidenced by abandoned channels, oxbows, crescent-shaped edges of low terraces, and other visible features indicating where the river has been in the past.  Mapping tools are used to draw a line along these outer limits to define the river corridor on either side of the river channel. The corridor limits are being refined by viewing historical aerial photographs and topographic maps that may show previous locations of the channel before such evidence became less distinct with time. The corridor limits established from remote sensing data are being field checked for accuracy.

The identification of river corridors will also reveal those areas most likely to experience rapid changes during a flood and thus highlight high priority areas for conservation and protection from future development.

Land conservation must be viewed as a new paradigm in river restoration. The current focus on engineering projects leads to immediate but often unsustainable improvements in river function that are locked in place and unable to adjust to future climate change.  Corridor mapping provides a framework for identifying a new class of restoration project that allows rivers to more freely migrate through portions of a corridor thus increasing resiliency to climate change and protecting downstream areas with at-risk infrastructure. 

Franklin Conservation District’s river corridor mapping and protocol are being further advanced by the Franklin Regional Council of Governments’ work to create tools to accompany the mapping in the form of a model River Corridor Protection Overlay Zoning District Bylaw and a River Corridor Easement being developed in partnership with the Franklin Land Trust.

These three pilot projects – river corridor mapping, a model river corridor protection overlay district and model river corridor easement tool form a complete toolkit to create an effective and efficient model for natural resources conservation that can be applied throughout the Commonwealth. FCD will work beyond the grant period to engage communities in working with the mapping protocols and the associated land protection tools for river corridor management.



1 Yellen, et al., 2014.Source, conveyance and fate of suspended sediments following Hurricane Irene. New England, USA. Geomorphology v. 226, p. 124-134.

2Yellen, et al., 2016. Historically unprecedented erosion from Tropical Storm Irene due to high antecedent precipitation. Earth Surf. Process. Landforms, Wiley Online Library, DOI: 10.1002/esp.3896.

 


 

Sawmill River Implementation Project: An Ecosystem Approach to Restoration

Why this project?

The Franklin Conservation District (FCD) is working with the Town of Montague to improve the water quality and habitat of the Sawmill River.

FCD was awarded a s.319 grant by the MA Department of Environmental Protection (with funds from the U.S. Environmental Protection Agency) to address long-standing problems of the river. With these funds a portion of the Sawmill River will be restored to a more natural stream channel which will decrease bank erosion and the river's sediment load to improve water quality and wildlife and aquatic habitats.

Photo: Vanasse Hangen Brustlin (VHB)

The Sawmill flows through forested, steep terrain in its upper reaches and in the lower reaches through cropland, pasture, forest, residential and commercial areas. Over the past thirty years, towns in the Sawmill River watershed have been plagued by numerous problems associated with the river. Flooding from storms and seasonal high water flows have damaged farmland and private property. Sediment has accumulated beneath bridges, threatening bridge safety, and eroding stream banks imperil roads. Water quality, fisheries and wildlife habitat have been harmed by increased sediment loads and bank scouring.

Photo: Vanasse Hangen Brustlin (VHB)

For several decades communities have attempted to apply "quick fixes" to these problems. Stream bank stabilization and dredging projects were undertaken to repair catastrophic damage to roads, bridges and agricultural areas. While these emergency responses were necessary at the time, they did not provide long-term solutions. Each time one problem was fixed, other problems emerged.

Toward restoration

In 2005 a restoration plan was developed based upon a three-phase geomorphic assessment that was used to analyze health indicators of the river's ecosystem. A team of stream restoration consultants from Vanasse Hangen Brustlin, Inc. and Field Geology Services used the data and findings to develop conceptual solutions for flooding, erosion and sedimentation using natural stream channel principles.

Now this team of consultants are working with FCD, the Town of Montague and state and federal agencies to finalize restoration plans for an approximately 1,700 foot reach of the Sawmill west of Route 63. The project site is on land owned by the MA Division of Fisheries and Wildlife which recently signed a License Agreement with FCD to conduct the river restoration on the property.

Project site in yellow: Courtesy VHB

What will the restoration do?

The proposed design will allow the river to connect with its floodplain. A series of strategically placed rock cross vanes, log vanes and root wads will help direct some of the river's flow into existing side channels and away from eroding stream banks. These "bioengineered" methods will help create a more natural stream channel with the pool-riffle-run-glide structure that is beneficial for trout and other aquatic life. By directing some of the flow into side channels, less sediment will be carried in the main channel, thus improving water quality in the reach.

Proposed Concept Design

The restoration will also improve habitat for two state-listed Species of Concern, the Brook Snaketail Dragonfly (Ophiogomphus aspersus) and Longnose Sucker (Catostomus catostomus).

Brook Snaketail Dragonfly (Ophiogomphus aspersus) and Longnose Sucker (Catostomus catostomus)

What is happening now?

The team from VHB has submitted permit applications to local, state and federal agencies along with proposed final designs. These agencies will review the documents, conduct site visits and accept public comment. When all permits have been received, a construction contractor will be hired to do the work. Our goal is to have the restoration completed by late summer of 2012.

Will this project fix all the Sawmill's problems?

The short answer is, no. This project is a first step toward a longer term goal of doing more restoration of the Sawmill River. It will also be an important demonstration of the use of bioengineered methods, which while widely used in other parts of the Northeast, have had limited application in Massachusetts.

Where can I obtain more information?

For more information please contact Deborah Shriver, Franklin Conservation District Grant Administrator via email at: debbieshriver@gmail.com or phone 413-665-8142. Check back on this site for updates.

Update - August 28, 2012

The Franklin Conservation District has recently finalized a contract with SumCo Eco-Contracting, LLC of Salem, MA to do the Sawmill River restoration. The firm was among five which submitted bids for the project. Work is set to begin in the week after Labor Day and will last approximately one month.

We'll post photos as construction gets underway.