Lamoille River Corridor Plan Johnson to Cambridge Lamoille County, Vermont February 22, 2017

Prepared by:

Lamoille County Planning Commission P.O. Box 1637, 52 Portland Street Morrisville, VT 05661

With assistance from:

Bear Creek Environmental, LLC 149 State St., Suite 3 Montpelier, Vermont 05602

Lamoille River Corridor Plan

TABLE OF CONTENTS 1.0 INTRODUCTION ...... 1 2.0 LOCAL PLANNING PROGRAM OVERVIEW ...... 2

2.1 RIVER CORRIDOR PLANNING TEAM ...... 2 2.2 GOALS AND OBJECTIVES OF THE PROJECT ...... 2 2.2.1 State River Management Goals and Objectives ...... 2 2.2.2 Local Goals and Objectives ...... 3 3.0 BACKGROUND WATERSHED INFORMATION ...... 3

3.1 GEOGRAPHIC SETTING ...... 3 3.1.1 Watershed Description...... 3 3.1.2 Political Jurisdictions ...... 3 3.1.3 Land Use ...... 3 3.2 GEOLOGIC SETTING ...... 6 3.3 GEOMORPHIC SETTING ...... 7 3.3.1 Description and Mapped Location of the Assessed Reaches ...... 7 3.3.2 Longitudinal Profile, Alluvial Fans, and Natural Grade Controls ...... 9 3.3.3 Valley and Reference Stream Types ...... 9 3.4 HYDROLOGY ...... 10 3.4.1 USGS Gage and/or Stream Stats Information ...... 10 3.4.2 Flood History ...... 10 3.5 ECOLOGICAL SETTING ...... 12 4.0 METHODS ...... 14

4.1 FLUVIAL GEOMORPHIC AND HABITAT ASSESSMENT PROTOCOLS ...... 14 4.1.1 Phase 1 Methodology ...... 14 4.1.2 Phase 2 Methodology ...... 14 4.1.3 Bridge and Culvert ...... 14 4.2 QUALITY CONTROL/QUALITY ASSURANCE PROCEDURES ...... 15 5.0 PHASE 1 AND PHASE 2 ASSESSMENT RESULTS ...... 15

5.1 PHASE 1 RESULTS ...... 15 5.1.1 SGAT ...... 15 5.1.2 SGAT, Remote Sensing, Local Knowledge, and Field Verification ...... 16 5.1.3 Lamoille River Report Impact Rating Methodology and Reach Results Summary ...... 16 5.1.4 Watershed Land Cover/Land Use- Step 4.1 ...... 16 5.1.5 Corridor Land Cover/Land Use- Step 4.2 ...... 17 5.1.6 Riparian Buffer Width- Step 4.3...... 17 5.1.7 Channel Modifications- Step 5.4 ...... 17 5.1.8 Dredging and Gravel Mining History- Step 5.5 ...... 18 5.1.9 Depositional Features- Step 6.3 ...... 18 5.1.10 Meander Migration/ Channel Avulsions- Step 6.4 ...... 18 5.1.11 Meander Width Ratio-Step 6.5 ...... 18 5.2 PHASE 2 RESULTS ...... 19 5.3 BRIDGE AND CULVERT ASSESSMENT ...... 23 6.0 STRESSOR, DEPARTURE AND SENSITIVITY ANALYSIS ...... 25

6.1 DEPARTURE ANALYSIS AND STRESSOR IDENTIFICATION ...... 25 6.1.1 Hydrologic Regime Stressors ...... 25 6.1.2 Sediment Regime Stressors ...... 25 6.1.3 Reach Scale Sediment Regime Stressors ...... 26 6.1.4 Channel Slope Modifiers ...... 27 6.1.5 Boundary Conditions and Riparian Modifiers ...... 27 6.1.6 Constraints to Sediment Transport and Attenuation ...... 28 6.2 SENSITIVITY ANALYSIS ...... 30

7.0 PRELIMINARY PROJECT IDENTIFICATION AND PRIORITIZATION ...... 31

7.1WATERSHED-LEVEL OPPORTUNITIES ...... 32 7.2 REACH-LEVEL OPPORTUNITIES ...... 34 7.3 PREVIOUS SITE LEVEL RESTORATION EFFORTS ...... 46 7.4 PROPOSED SITE LEVEL RESTORATION OPPORTUNITIES ...... 46 7.5 NEXT STEPS ...... 56 8.0 GLOSSARY OF TERMS ...... 57 9.0 REFERENCES...... 60

EXECUTIVE SUMMARY Lamoille River Corridor Plan Johnson to Cambridge, Vermont

The Phase 2 stream geomorphic assessment study area focused on 6 stream reaches between the Railroad Street in Johnson and Pumpkin Harbor Rd in Cambridge Village. The Lamoille River HUC 1 has a watershed size of 182 square miles at the downstream end of the study area in Cambridge, Vermont. The combined length of the river reaches assessed is approximately 15 miles. The Lamoille River within the study area flows east to west through the Towns of Johnson and Cambridge. The Lamoille continues to flow westerly downstream of Cambridge and eventually joins Lake Champlain in Milton at an elevation of 95 feet above sea level.

The Lamoille River reaches from Johnson to Hardwick were previously assessed and documented in a companion report (2010) entitled “Lamoille River Corridor Plan - Hardwick to Johnson, Vermont.”

Four of six assessed reaches in the Lamoille HUC 1 study area (R08, R09, R11 and R13) were found to be in fair geomorphic condition. One reach, R12 was assessed as good geomorphic condition (based on administrative judgment) and one reach, R10 was assessed as poor condition. Geomorphic condition is determined based on the degree (if any) of channel degradation, aggradation, widening, and planform adjustment. Degradation is the term used to describe the process whereby the stream bed lowers in elevation through erosion or scour of bed material. Aggradation describes the raising of the bed elevation through an accumulation of sediment. The planform is the channel shape as seen from the air. Planform change can be the result of a straightened course imposed on the river through different channel management activities or a channel response to other adjustment processes such as aggradation and widening. The most common adjustment processes in the Lamoille River study area between Johnson and Cambridge are widening, aggradation and planform adjustment as a result of historic degradation within the channel.

Lamoille River The main stem of the Lamoille River is experiencing high rates Johnson to Cambridge of bank erosion. The bank erosion has been accelerated due Watershed Size 182 sq. miles to land use activities and channel and floodplain modifications. Significant channel straightening, bank armoring, berming, and Length of Assessed 15 miles floodplain encroachment have occurred within this river Reaches system both on the main stem and major tributaries. Along Phase 1 by LCPC 2005 much of the main stem, the river channel is currently migrating laterally to recreate a new floodplain at a lower elevation to Phase 2 by BCE 2006 dissipate energy and become more stable. As the river works toward a more stable equilibrium, the communities of Johnson Bridge and Culvert 2006 and Cambridge have the opportunity to reestablish floodplain Survey by BCE vegetation and protect the river from further encroachments through the adoption of fluvial erosion hazard zones. Phase 2 Focus Main Stem Site specific projects are identified for the Lamoille River main Most Common Widening, stem in the river corridor plan. The project strategy, technical Active Adjustment aggradation feasibility, and priority for each project are listed by project Process and Planform number and reach. High priority projects include river migration corridor easements and floodplain restoration projects to Total Number of 12 provide attenuation of sediment and floodwaters, riparian Potential Projects buffer improvement areas, and the replacement of undersized Number of Potential 4 bridges and culverts. Municipal Projects A floodplain restoration project was completed on the Number of Potential 8 Lamoille main stem by the Vermont Agency of Natural Landowner Projects Resources in 2008. One of the project sites; R11, is located within the section between Johnson and Cambridge. The project reconnected floodplain access by lowering the old rail bed.

Lamoille River Corridor Plan Johnson to Cambridge Lamoille County, Vermont

1.0 INTRODUCTION

This river corridor plan includes the Lamoille River main stem from Johnson to Cambridge, Vermont. The River Corridor Planning effort was sponsored by the Lamoille County Planning Commission (LCPC) with funding provided through a grant from the Agency of Natural Resources (formerly) Clean and Clear Program and LCPC’s Emergency Management Planning Grant from the Vermont Department of Emergency Management and Homeland Security. The Vermont Department of Environmental Conservation (DEC) River Management Program provided technical expertise and shared quality control/quality assurance responsibilities with Bear Creek Environmental (BCE). The River Corridor Plan (RCP) followed the Vermont Agency of Natural Resources River Corridor Planning Guide (Vermont Agency of Natural Resources, 2007a). Information for the RCP came from the DEC, the Vermont Center for Geographic Information (VCGI), and field data collected by Bear Creek Environmental, LLC.

The primary objective of the RCP is to use stream geomorphic assessment data to identify and prioritize river corridor protection and restoration projects within the Lamoille River watershed in the Towns of Johnson and Cambridge. A planning strategy based on fluvial geomorphic science (see glossary at end of report for associated definitions) was chosen because it provides a holistic, watershed-scale approach to identifying the stressors on river ecosystem health. The stream geomorphic assessment data can be used by resource managers, community watershed groups, municipalities and others to identify how changes to land use alter the physical processes and habitat of rivers. The Vermont Stream Geomorphic Assessment Protocol includes three phases: 1. Phase 1- Remote sensing and cursory field assessment; 2. Phase 2 – Rapid habitat and rapid geomorphic assessment to provide field data to characterize the current physical condition of a river; and 3. Phase 3 – Detailed survey information for designing “active” channel management projects.

A Phase 1 Stream Geomorphic Assessment following Agency of Natural Resources Protocols was completed for the Lamoille River by LCPC in 2005. The LCPC then retained Bear Creek Environmental to perform Phase 2 Stream Geomorphic Assessments and Bridge and Culvert Assessments of select reaches of the Lamoille River during 2006, including the reaches focused on in this report in the towns of Johnson and Cambridge. These stream geomorphic assessments provide information about the physical condition of the Lamoille River watershed and the factors that influence the stability of these systems.

River Corridor Plan Page 2 Lamoille River from Johnson to Cambridge Lamoille County Planning Commission 2.0 LOCAL PLANNING PROGRAM OVERVIEW

2.1 RIVER CORRIDOR PLANNING TEAM

The river corridor planning team for the Lamoille River watershed was comprised of the Lamoille County Planning Commission, the Agency of Natural Resources, Bear Creek Environmental, local municipalities and landowners. This planning effort was sponsored by the Lamoille County Planning Commission. Funding for the project was provided through grants from the Vermont Agency of Natural Resources and the Vermont Department of Emergency Management and Homeland Security. Staci Pomeroy from the Vermont River Management Section of the Vermont Agency of Natural Resources (VANR) provided technical guidance for this project.

2.2 GOALS AND OBJECTIVES OF THE PROJECT

The LCPC, as part of the grant with the Agency of Natural Resources, hired Bear Creek Environmental, LLC to conduct a Phase 2 geomorphic assessment for the Lamoille River from Johnson to Cambridge. LCPC developed the River Corridor Plan with assistance from Staci Pomeroy of the Vermont River Management Program. The primary objective of the River Corridor Plan is to use the Phase 1 and 2 Assessment data to identify and prioritize river corridor protection and restoration projects within the study area. Bridge and culvert data collected during the Phase 2 Assessment were used to identify structures that have the potential to fail because of channel adjustments, are having a geomorphic impact on the stream, or are impeding aquatic organism passage.

2.2.1 State River Management Goals and Objectives

The State of Vermont’s River Management Program has set out several goals and objectives that are supportive of the local initiative in the Lamoille River watershed from Johnson to Cambridge. The state management goal is to, “manage toward, protect, and restore the fluvial geomorphic equilibrium condition of Vermont rivers by resolving conflicts between human investments and river dynamics in the most economically and ecologically sustainable manner” (Vermont Agency of Natural Resources, 2007a). The objectives of the Program include: fluvial erosion hazard mitigation; sediment and nutrient load reduction; and aquatic and riparian habitat protection and restoration. The Program seeks to conduct river corridor planning in an effort to remediate the geomorphic instability that is largely responsible for these problems in a majority of Vermont’s rivers. Additionally, the Vermont River Management Program has set out to provide funding and technical assistance to facilitate an understanding of river instability and the establishment of well-developed and appropriately scaled strategies to protect and restore river equilibrium.

River Corridor Plan Page 3 Lamoille River from Johnson to Cambridge Lamoille County Planning Commission 2.2.2 Local Goals and Objectives

A community-based river corridor management plan provides many opportunities for enhancing and restoring the Lamoille River Watershed. Some of the local goals are listed below:  Identify watershed, floodplain and channel impacts along each priority reach  Evaluate geomorphic condition and habitat condition  Identify stream channel adjustment processes  Conduct bridge and culvert assessments  Verify valley walls identified in Phase 1 assessment  Participate in public meetings to inform local stakeholders of study findings  Identify potential stream restoration projects.

3.0 BACKGROUND WATERSHED INFORMATION

3.1 Geographic Setting

3.1.1 Watershed Description

BCE was contracted to conduct Phase 2 Assessments on selected reaches of the Lamoille River watershed (Figure 1), including those between the Railroad Street Bridge in Johnson and the “Wrong Way” Bridge in Cambridge. The Lamoille River HUC 1 watershed is 182 square miles at the Wrong Way Bridge in Cambridge, Vermont, the most downstream reach break (Figure 2). The Lamoille River watershed drains from approximately 1350 feet elevation at East Greensboro, Vermont, westerly through the spine of the northern Green Mountains and empties into Lake Champlain at the Sand Bar National Waterfowl Management Area at approximately 95 feet above sea level. The study area included in this report focused on the 6 stream reaches between the Railroad Street Bridge in Johnson and the Wrong Way Bridge in Cambridge (Figure 2).

The upper-most reach in the study area (R13), which begins in Johnson, is approximately 62 feet higher in elevation than the lowest reach (R08) in Cambridge. All reaches assessed in the Phase 2 investigation have a channel slope of less than 1 percent.

3.1.2 Political Jurisdictions Phase 2 and RCP project reaches for the study area are located in Lamoille County Vermont within the Towns of Johnson and Cambridge. This portion of the Lamoille River watershed falls under the jurisdiction of the Lamoille County Planning Commission.

3.1.3 Land Use

The study area is dominated by forested land, however agricultural and urban land uses are subdominant within the watershed (Figure 3).

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Figure 1: Project location map

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Figure 2: Detailed reach location map for Phase 2 Assessments and RCP

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Figure 3. Land cover and land use for Mid-Lamoille River Watershed

3.2 Geologic Setting The Lamoille River watershed is located within the Green Mountain Geo-physiographic Province. The Green Mountains were uplifted during the Taconic orogeny about 455 million years ago (Doolan, 1996). The bedrock underlying the study area of the Lamoille watershed primarily includes the Moretown member of the Missisquoi Formation in the eastern part of the watershed. The Moretown member of the Missisquoi Formation is comprised of quartzite and quartz-plagioclase granulite separated by thin layers of minerals and also phyllite and schist. The Stowe Formation is located in the center of the watershed and is comprised of quartz and chlorite phyllite and schist with abundant segregations of granular white quartz. Located within the Stowe formation in this area is greenstone and amphibolite. On the western side of the study area, the Hazens Notch Formation is dominant. The Hazens Notch Formation is an interbedded carbonaceous and non- carbonaceous schist that grades to quartzite and gneiss (Doll, 1961).

The Green Mountains and adjacent valleys have been covered with ice during historic glacial periods. The last large ice sheet, the Laurentide Ice Sheet, covered all of New England and advanced up the Lamoille River Valley. As the climate warmed, the glacier slowly retreated

River Corridor Plan Page 7 Lamoille River from Johnson to Cambridge Lamoille County Planning Commission and glacial lakes were dammed in the Lamoille River valley. Following the retreat of the ice sheet, the Lamoille River and its tributaries began eroding the glacial and lake sediments that were left behind (Wright, 2003).

Based on Natural Resource Conservation Service (NRCS) soils information the dominant surficial geology of the study area within the Lamoille River watershed consists of alluvial deposits. The downstream end of the study area is predominately glacial outwash (ice- contact deposits) and the upstream end of the study area is mostly glacial till. The study area is comprised of soils with erodibility ranging from slight (R10 and R11) to severe (R12). Three of the six assessed reaches (R08, R09, and R13) had moderately erodible soils. Where there are highly erodible soils there is a higher potential for sediment input to the stream channel.

3.3 Geomorphic Setting 3.3.1 Description and Mapped Location of the Assessed Reaches The Phase 2 study focused on 6 stream reaches on the main stem of the Lamoille River within the Towns of Johnson and Cambridge from the Railroad Street Bridge in Johnson downstream to the Wrong Way Bridge in Cambridge. The combined length of the stream reaches assessed is approximately 15 miles (Figure 2).

The Lamoille River watershed was divided into reaches for the Phase 1 and Phase 2 Stream Geomorphic Assessments. Each reach represents a similar section of the stream based on physical attributes such as valley confinement, slope, sinuosity, bed material, dominant bedform, land use, and other hydrologic characteristics. Each point represents the downstream end of the reach. The hydrological unit code (HUC) 1 portion of the watershed (from Johnson to Cambridge) is included in this corridor plan. A separate corridor plan was prepared for the HUC 2 part of the watershed that includes the Lamoille River from Hardwick to Johnson. Corridor plans have been prepared for major tributaries of the Lamoille River within the HUC 1 watershed under the direction of the LCPC. These subwatersheds (see Figure 4) are listed below with a reference to the river corridor plan or phase 1 report.  Brewster River Corridor Plan – Fitzgerald Environmental Associates, LLC (2015)  Foote Brook Phase 1 and 2 Report – LCPC and Bear Creek Environmental, LLC (2010)  Gihon River Corridor Plan - LCPC and Bear Creek Environmental, LLC (2009)  North Branch Lamoille River Phase 1 Geomorphic Assessment completed by Bear Creek Environmental, LLC in 2008 (no Phase 1 Report completed)

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Figure 4. Geomorphic Assessments Completed in the Lamoille River (HUC1) Watershed

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3.3.2 Longitudinal Profile, Alluvial Fans, and Natural Grade Controls Only one natural bedrock grade control, Ithiel Falls was noted in R12. The steepness of the valley side slopes was determined using a combination of a topographic map and the soils layer.

3.3.3 Valley and Reference Stream Types Reference stream types are defined as stream channel forms and processes that would exist in the absence of human-related changes to the channel, floodplain, and/or watershed. Stream and valley characteristics including valley confinement, and slope determined from digital USGS topographic maps were used to determine the stream type. The reference reach characteristics were later refined during the windshield survey and Phase 2 Assessment. Reference reach typing was based on both the Rosgen (1996) and the Montgomery and Buffington (1997) classification systems.

Table 1: Reference Stream Type

Stream Type Confinement Valley Slope Bed Form

A Narrowly Very steep > Cascade Confined 6.5 % A Confined Very steep 4.0 - Step-Pool 6.5 % B Confined or Semi- Steep Step-Pool confined 3.0 – 4.0 % B Confined, Semi- Moderate to Plane Bed confined or Steep Narrow 2.0 – 3.0 % F Semi-confined Moderate to Bedrock Gentle <2.0 % C or E Unconfined Moderate to Riffle-Pool or (Narrow, Broad Gentle Dune-Ripple or Very Broad) <2.0 % D Unconfined Moderate to Braided Channel (Narrow, Broad Gentle or Very Broad) <4.0 %

Table 1 shows the typical characteristics used to determine reference stream types (Vermont Agency of Natural Resources, 2005). Reference stream types for the assessed reaches within the project area are summarized in Table 2. The majority of the stream reaches are “C” stream types which tend to have unconfined valleys and gentles slopes. Reach R12 has a similarly gentle valley slope, but has a semi-confined valley with a reference stream type of “F”.

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Table 2: Geomorphic Setting of Assessed Reaches

Reach Reference Confinement Valley Bed Form ID Stream Type Slope R13 C Narrow 0.1 Riffle-Pool R12 F Semi-confined 0.2 Bedrock R11 C Very Broad 0.0 Riffle-Pool R10 C Very Broad 0.08 Dune-Ripple R09 C Broad 0.0 Dune-Ripple R08 C Broad 0.1 Riffle-Pool

3.4 Hydrology 3.4.1 USGS Gage and/or Stream Stats Information

In order to better understand the flood history of the Lamoille River, long term data from the U.S. Department of the Interior, U.S. Geological Survey (USGS) gauge on the Lamoille River in Johnson, VT were obtained (USGS, 2007). Ninety-three years of record are available for the Lamoille River gauge at Johnson, VT which provides a continuous record of flow from 1912 through to the present.

The near-term record for the Lamoille River shows that a 25-year flood event has been exceeded three times over the period of record (1973, 1995 and 2011). The long term record on the Lamoille gauge shows major flood events also occurred in the years 1912, 1936, 1983 and 1997. The graph below (Figure 5) provides a flood frequency analysis for the Lamoille River gauge.

3.4.2 Flood History

Between 1995 and 1998 Vermonters suffered nearly $60,000,000 in flood damages; much of these losses were avoidable. Through Vermont’s history, flood waters on the Lamoille River have destroyed property on numerous occasions. Precipitation trend analysis suggests that intense, localized storms, which can cause flash flooding, are occurring with greater frequency.

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Figure 5. Flood frequency analysis for Lamoille River at Johnson, VT

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3.5 Ecological Setting The Lamoille River watershed between Johnson and Cambridge lies almost exclusively within the Northern Green Mountains biophysical region (Figure 7). This region is characterized by Thompson and Sorenson (2005) as having high elevations and cool summers. The Green Mountains have a strong influence on the weather resulting in an abundance of precipitation in the form of both rain and snow. Northern hardwood forest is the dominant community in this biophysical region. The Northern Green Mountains provide important habitat for both aquatic and terrestrial animals. According to Thompson and Sorenson (2005), the Green Mountains offer extensive habitat for black bear, white- tailed deer, bob cat, fisher, beaver and red squirrel. Birds such as Blackpoll Warblers, Swainson’s Thrush and the rare Bicknell’s Thrush nest in the high elevation forests. Deer wintering areas identified by the Vermont Department of Fish and Wildlife (Figure 6) are common adjacent to the Lamoille River in Johnson and Cambridge. Concentrated areas of wetland (included in the Vermont Significant Wetland Inventory) exist within the Long Trail State Forest in Belvidere and Eden, in the Babcock Reserve owned by Johnson State College and in North Hyde Park.

Public lands include within the Lamoille watershed between Johnson and Cambridge include:

 Long Trail State Forest  Babcock Nature Preserve  Mount Mansfield State Forest  Green River Reservoir State Park  Johnson Town Forest

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Figure 6. The ecological setting of the Lamoille River Watershed between Johnson and Cambridge

River Corridor Plan Page 14 Lamoille River from Johnson to Cambridge Lamoille County Planning Commission 4.0 METHODS 4.1 Fluvial Geomorphic and Habitat Assessment Protocols

4.1.1 Phase 1 Methodology

A Stream Geomorphic Assessment process is divided into three phases, based on VANR protocols. Phase 1, the remote sensing phase, involves the collection of data from topographic maps and aerial photographs, from existing studies, and from very limited field studies called “windshield surveys” (Vermont Agency of Natural Resources, 2005). The Phase 1 assessment provides an overview of the general physical nature of the watershed.

The Phase I assessment followed procedures specified in the Vermont Stream Geomorphic Assessment Phase 1 Handbook (Vermont Agency of Natural Resources, 2005), and used version 4.53 of the Stream Geomorphic Assessment Tool (SGAT) GIS extension. All assessment data were recorded on the Agency of Natural Resources (VANR) Phase I data sheets and were entered into the VANR Data Management System (DMS).

4.1.2 Phase 2 Methodology

The Phase 2 assessment of the Lamoille River followed procedures specified in the Vermont Stream Geomorphic Assessment Handbook Phase 2 (Vermont Agency of Natural Resources, 2007b). All assessment data were recorded on the Agency of Natural Resources Phase 2 data sheets, and were entered in to the VANR Stream Geomorphic Assessment data management system (DMS). The Phase 1 database was updated using the field data from the Phase 2 assessment in 2006.

The parameters and protocols used for undertaking each of the above steps are outlined in the Phase 2 Handbook (Vermont Agency of Natural Resources, 2007b). The entire length of each Phase 2 reach was walked to determine segment breaks. Bank erosion, grade control structures, bank revetments, debris jams, depositional features, stormwater inputs, flood chutes and other important features were mapped within all segments.

4.1.3 Bridge and Culvert The Bridge and Culvert Assessment and Survey Protocols specified in the Vermont Stream Geomorphic Assessment Handbook (Vermont Agency of Natural Resources, 2007b) were followed. All assessment data were recorded on the Vermont Agency of Natural Resources (VANR) Bridge and Culvert Assessment – Geomorphic and Habitat Parameters data sheet, and were entered into the VANR Data Management System (DMS).

The bankfull channel width from the regional curve was used to determine the expected bankfull width in the vicinity of a particular structure. Latitude and longitude at each of

River Corridor Plan Page 15 Lamoille River from Johnson to Cambridge Lamoille County Planning Commission the structures was determined using a Garmin Etrex Vista GPS unit. The assessment included photo documentation of the inlet, outlet, upstream, and downstream of each of the structures.

4.1.4 River Corridor Plan

Bear Creek Environmental (BCE) used SGAT version 4.53 to index features that were mapped during the Phase 2 assessment. BCE also indexed locations where riparian buffers are less than 25 feet on either side of the channel using SGAT version 4.56 based on orthophotography from 2003. LCPC reviewed and updated the indexed features based on 2013 aerial imagery.

The Vermont Agency of Natural Resources River Corridor Planning Guide (2007a) was followed to generate a series of stressor maps. These maps were created using indexed data from the Phase 1 and Phase 2 Stream Geomorphic Assessments along with existing data available from VCGI, including roads, buildings and driveways. The stressor maps were then used to identify potential project locations that have few constraints to channel adjustment.

4.2 Quality Control/Quality Assurance Procedures

To assure a high level of confidence in the Phase 1 and 2 SGA data, strict quality assurance/quality control (QA/QC) procedures were followed by BCE. These procedures involved a thorough in-house review of all data as well as automated and manual QC checks with the DEC River Management Program.

In 2006, BCE completed its own in-house QA review after all the Phase 2 data were entered into the Data Management System (DMS) and the Phase 1 data were updated. The Phase 1 DMS and ArcView shapefiles were updated by BCE based on the Phase 2 field assessment work during the Phase 2 QA/QC process in 2006. The DMS and the ArcView shapefiles for the Lamoille River Phase 2 study were submitted to Staci Pomeroy of the VANR for a Quality Assurance review in March 2007. Some minor revisions were made by BCE to the DMS following this review.

5.0 PHASE 1 AND PHASE 2 ASSESSMENT RESULTS

5.1 Phase 1 Results

5.1.1 SGAT Using the Stream Geomorphic Assessment Tool (SGAT), numerous parameters were calculated including: valley width, length, and slope; channel length and slope; stream confinement; sinuosity; and reference channel width. Based on this data, reference stream types were classified according to characteristics of the valley, geology, and climate of the stream. The reference stream type describes the natural channel tendency of channel form and process in the absence of human-related changes to the channel.

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5.1.2 SGAT, Remote Sensing, Local Knowledge, and Field Verification Using a combination of SGAT, remote sensing, local knowledge, and windshield surveys (field verification) the following parameters and their respective impacts were inventoried and/or calculated, and assessed:

• Valley side slopes • River corridor delineation • River corridor and reach land use and land cover • Riparian buffer condition • Hydrologic groups • Soils and geology influences • Alluvial fans • Grade controls • River corridor development • Bank armoring • Bridge and culverts • Flow regulation and water withdrawal • Channel modifications • Flood plain encroachments • Dredging and channel mining history • Depositional features • Meander migration • Meander width ratio • Stream wavelength • Debris jam potential • Dominant bed form and materials

5.1.3 Lamoille River Report Impact Rating Methodology and Reach Results Summary

Phase 1 Parameters highlighted for data interpretation:

 Watershed Land Cover/Land Use  Corridor Land Cover/Land Use  Riparian Buffer Width  Channel Modification  Depositional Features  Meander Migration  Bridge and Culvert Survey-using Appendix G datasheet

5.1.4 Watershed Land Cover/Land Use- Step 4.1 Lakes, wetlands, and perennial vegetation play an important role in a watershed by storing water and trapping sediment, which helps reduce flood peaks and maintain summer base flows in rivers and streams. Urban development and cropland typically

River Corridor Plan Page 17 Lamoille River from Johnson to Cambridge Lamoille County Planning Commission increase the peak and change the duration of stormwater and sediment runoff events. Recent orthophotos were used to evaluate this parameter.

High impact rating scores indicate 10% or more of the reach watershed is crop and/or urban. Reach R13 was the only reach that recorded high impact ratings for watershed land use land cover. However, all of the other reaches had impact ratings of at least 8%.

5.1.5 Corridor Land Cover/Land Use- Step 4.2 Land use/land cover within the stream corridor is particularly important with respect to sediment deposition and erosion during annual flood events. Wetlands, ponds, and perennial vegetation moderate stormwater and sediment runoff, while impervious surfaces within urban areas and the exposed soils found in cropland have the potential to increase watershed inputs.

High impact rating scores indicate 10% or more of the reach corridor is crop and/or developed. All six reaches included in this assessment resulted in high impact rating scores. The scores ranged from 18.3% to 52%.

5.1.6 Riparian Buffer Width- Step 4.3 The riparian buffer is the area of land directly adjacent to the channel along the channel’s banks and floodplain that is covered with native woody vegetation and largely unmanaged. Riparian buffers protect and enhance water quality, fish and wildlife habitats, aesthetics, and recreational values associated with streams. Streams without riparian vegetation often experience high rates of lateral erosion and may see such large increases in sediment that they undergo major adjustment of channel dimension, pattern, and profile. Orthophotos were used to estimate the percent of each buffer width category along the right and left banks.

High impact rating scores indicate that 75% of the reach has little or no buffer (0-25 feet) on one or both banks. All six reaches included in this assessment resulted in high impact rating scores for riparian buffer width.

5.1.7 Channel Modifications- Step 5.4 Channelization is the process of changing the natural path of a river through activities such as windrowing and straightening. A channelized stream may degrade, or cut down vertically into its bed and cause the channel to lose access to its floodplain. The sediment resulting from the degradation process is re-deposited downstream of the channelized area. This results in aggradation, or building up, of the channel bed in this downstream area. Aggradation can result in channel widening, bank instability, and other channel responses, most of which are detrimental to both riverside land and aquatic habitat. Interviews with natural resource professionals, and review of orthophotos and topographic maps were used to examine this parameter.

High impact rating scores indicate that greater than 20% of the reach had been channelized. All reaches except R12 resulted in high impact scores. The percent of channelization for these high impact scores ranged from 25.4% to 94.6%.

River Corridor Plan Page 18 Lamoille River from Johnson to Cambridge Lamoille County Planning Commission 5.1.8 Dredging and Gravel Mining History- Step 5.5 Dredging and mining gravel bars from a channel may initiate a channel evolution process. Such activities straighten and steepen the channel and cause the river to cut down and erode its bed. The stream channel eventually aggrades with sediment supplied from upstream reaches as headcuts in the streambed move up-valley. Information and records from DEC’s Stream Alteration Engineer was used to determine the relative frequency and volume of gravel extraction.

High impact rating scores indicate that the reach was historically used for commercial gravel mining and/or dredged for flood remediation. None of the assessed reaches had a high impact rating score for this parameter

5.1.9 Depositional Features- Step 6.3 An unvegetated bar is sign that the bar was recently formed and is growing. Mid-channel bars, large unvegetated point bars, and delta bars may indicate an increased sediment load (from upstream) and the high likelihood that the streambed is actively aggrading and/or undergoing rapid lateral movement. The sediment sources for these bars may be from bank failures or the degradation of the channel upstream. It may also be from upland watershed sources. Orthophoto interpretation and windshield surveys were used to evaluate this parameter.

High impact rating scores indicate numerous, large unvegetated mid-channel, point and/or delta bars present. Reaches R08, R10, and R11 resulted in high impact scores.

5.1.10 Meander Migration/ Channel Avulsions- Step 6.4 Some amount of lateral migration is natural in most alluvial stream systems, but the rate of migration may be increased in streams due to changes in the sediment supply and/or sediment transport capacity of the channel.

Comparisons of paths of the channel from similarly scaled orthophotos of different years were used to identify channel migration, bifurcation, and/or avulsions. Channel migration occurs as the channel erodes its outer banks on meander bends. Bifurcation describes when the stream has split into two or more active channels. An avulsion describes a channel plan form change due to meander cutoffs.

High Impact Rating scores indicate frequent occurrences of channel migration, bifurcation, and/or channel avulsions along the reach. R11 was the only reach that resulted in a high impact score.

5.1.11 Meander Width Ratio-Step 6.5 The meander belt width is the horizontal distance between the opposite banks of fully developed meanders. Unconfined, gravel-based streams in shallow-sloped valleys that are in regime have belt widths generally in the range of 5 to 8 times the width of the channel. Higher values may indicate that the stream, possibly due to an increase in fine sediment, has started to aggrade and become more sinuous, decreasing its channel slope as it migrates laterally. Lower values may indicate that the stream has become straighter and steeper, possibly degrading its bed and losing access to its floodplain.

River Corridor Plan Page 19 Lamoille River from Johnson to Cambridge Lamoille County Planning Commission

Orthophotos and topographic maps were used to determine the reach’s average belt width.

High impact rating scores indicate the meander width ratio is less than 3 or greater than 10, well outside the 5-8 range of reaches within regime. Reaches R08, R12 and R13 resulted in high impact ratings. The abnormally low meander width ratios of these reaches indicate a history of channel straightening, leading to degradation, incision and loss of floodplain access.

5.2 Phase 2 Results

Functioning floodplains play a crucial role in providing long term stability to a river system. Natural and anthropogenic impacts may alter the delicate equilibrium of sediment and discharge in natural stream systems and set in motion a series of morphological responses (aggradation, degradation, and widening and/or planform adjustment) as the channel tries to reestablish a dynamic equilibrium. Small to moderate changes in slope, discharge, and/or sediment supply can alter the size of transported sediment as well as the geometry of the channel; while large changes can transform reach level channel types (Ryan, 2001). Human- induced practices that have contributed to stream instability within the Lamoille River watershed include:

 Forest clearing  Channelization and bank armoring  Removal of woody riparian vegetation  Floodplain encroachments  Urbanization  Poor road maintenance and installation of infrastructure  Loss of wetlands

These anthropogenic practices have altered the delicate balance between water and sediment discharges within the Lamoille River watershed. Channel morphologic responses to these practices contribute to channel adjustment that may further create unstable channels.

Geomorphic Evaluation

The geomorphic condition for each Phase 2 reach is determined using the rapid geomorphic assessment (RGA) protocol, and is based on the degree of departure of the channel from its reference stream type (Vermont Agency of Natural Resources, 2005). The reference condition for each of the Phase 2 reaches was previously identified in Table 2. 4 of 6 assessed segments (R08, R09, R11 and R13) rated in the fair category for geomorphic condition. Reach R10 rated as poor for geomorphic condition. Figure 7 illustrates the geomorphic condition of the streams in relation to the watershed. Of the 6 reaches assessed on the main stem of Lamoille River, every reach had total impact scores of 18 or greater out of a possible score of 32. A total impact score greater than 18 is considered high. As part of this assessment, land use, encroachments, and buffer condition are analyzed

River Corridor Plan Page 20 Lamoille River from Johnson to Cambridge Lamoille County Planning Commission within 150 feet on each side of the river. Residential and agricultural land use within the river corridor accounted for the majority of these high impact scores on Lamoille River. Detailed reach summary data are provided in Appendix 1. Reach R12 did not receive a full geomorphic assessment because the channel is bedrock dominated.

The most common adjustment processes in the Lamoille River are widening and planform migration as a result of historic degradation within the channel. Degradation is the term used to describe the process whereby the stream bed lowers in elevation through erosion, or scour, of bed material. Aggradation is a term used to describe the raising of the bed elevation through an accumulation of sediment. The planform is the channel shape as seen from the air. Planform change can be the result of a straightened course imposed on the river through different channel management activities, or a channel response to other adjustment processes such as aggradation and widening. Channel widening occurs when stream flows are contained in a channel as a result of degradation or floodplain encroachment or when sediments overwhelm the stream channel and the erosive energy is concentrated into both banks.

River Corridor Plan Page 21 Lamoille River from Johnson to Cambridge Lamoille County Planning Commission

Figure 7: Phase 2 Geomorphic Condition of the Lamoille Watershed from Hardwick to Johnson

River Corridor Plan Page 22 Lamoille River from Johnson to Cambridge Lamoille County Planning Commission Table 3. Stream Type and Channel Evolution Stage

Segment Entrenchment Width to Reference Existing Channel Active Number Ratio Depth Stream Stream Evolution Adjustment Ratio Type Type Stage Process Aggradation Degradation R08 8.74 29.27 C C III Widening Planform Aggradation Degradation R09 6.67 24.86 C C III Widening Planform Aggradation Degradation R10 11.89 25.22 C C III Widening Planform Aggradation Degradation R11 14.18 25.08 C C III Widening Planform R12 Reach Not Assessed – Bedrock Aggradation Degradation R13 1.13 35.19 C F III Widening Planform Bold Red lettering - denotes extreme adjustment process (score <=5) Bold Black lettering – denotes major adjustment process (score >5<=10) Black lettering (no bold) – denotes minor adjustment process (score >10<=15)

Habitat Evaluation

Table 4 below shows a comparison of the habitat condition based on the Rapid Habitat Assessment (RHA) and the geomorphic condition based on the Rapid Geomorphic Assessment (RGA). For 4 of 6 assessed segments, both the RHA and the RGA resulted a fair rating, implying that the ecological health of the Lamoille River from Johnson to Cambridge is closely related to the geomorphic condition of the stream. In general several of the study reaches lacked a strong riffle-pool bedform and the diversity of habitat features that this brings. Many reaches involved in the study had major intrusion into their river corridor from Route 15 and other major roads and many had inadequate riparian buffers due to historic and /or recent land clearing.

Table 4. Comparison of RHA and RGA for Phase 2 Reaches

Segment Score RHA Score RGA Rating RHA Rating RGA Number R08 0.41 0.41 Fair Fair R09 0.41 0.47 Fair Fair

River Corridor Plan Page 23 Lamoille River from Johnson to Cambridge Lamoille County Planning Commission Table 4. Comparison of RHA and RGA for Phase 2 Reaches

Segment Score RHA Score RGA Rating RHA Rating RGA Number R10 0.43 0.43 Fair Poor R11 0.39 0.44 Fair Fair R12 Not Assessed – Bedrock R13 0.40 0.36 Fair Fair

5.3 Bridge and Culvert Assessment

A watershed-wide bridge and culvert inventory and assessment was conducted to determine if stream crossings were contributing to localized streambank erosion, sedimentation, and impaired fish passage. Six bridges/arches were included in the assessment of stream crossings conducted with the Phase 2 field work in 2006. The geomorphic and habitat data for this bridge and culvert assessment were collected following the VANR protocol.

Bridge spans and culvert diameter measurements were compared to calculated bankfull width measurements. The bankfull width, also known as the channel forming flow, is directly related to watershed drainage area. The bankfull flow is the discharge at which the majority of erosion and deposition takes place. Undersized bridges and culverts are not designed to accommodate both flow and sediment. During flood events large point bars can consequently deposit upstream of undersized bridges and culverts. During catastrophic flood events crossings can become outflanked, taking out large sections of roads and driveways. Significant sediment discharges to waterways can result. Sedimentation of the river poses water quality and aquatic habitat concerns. Of the six bridges assessed, only one (R09) was less than 80% of the bankfull width.

All bridges assessed are owned by the State of Vermont. In order to assist VTrans with priorities for replacement or retrofit of the structures, a priority list was generated using the information and photographs taken during the assessment. The bridge span as a percentage of the channel width was used as a first cut in prioritizing the structures for replacement. The following categories were used as a second cut to determine project priorities for stream crossings.

High Priority: Bridges and culverts with spans of approximately 50 percent of the bankfull width or less, which are significantly impeding natural sediment transport or are blocking aquatic organism passage (AOP).

Moderate Priority: Bridges and culverts with spans less than 50 percent that are not causing significant geomorphic instability or blocking AOP and structures with spans greater than 50% that are causing instability and/ or impeding aquatic organism migration are also in this category.

Low Priority: Stream crossing structures that are not included in either of the two categories above. River Corridor Plan Page 24 Lamoille River from Johnson to Cambridge Lamoille County Planning Commission Table 5 below provides a summary of the stream crossings assessed within the study area. There were 6 bridges assessed as part of the Phase 2 assessment and no culverts. Two bridges located in R09 were assigned a moderate priority for replacement/retrofit. One of these, the Cambridge Junction covered bridge, is a historic burr arch structure that was renovated in 2004 and 2015. Since its historic character would preclude replacement, retrofit of the bridge abutments might be considered to reduce impacts. The other bridge is a railroad bridge on the Lamoille Valley Rail Trail. In the winter of 2015-2016, ice jams knocked down wooden piers supporting one side of the railroad bridge and that portion of supported by the piers was removed. There are currently plans to replace and retrofit the bridge in the near future. The bridge over Rt 108 in Jeffersonville has been replaced (2014) since the field data collection; therefore it is not recommended for replacement. The other bridges not recommended for replacement are relatively new bridges in good condition, with percent channel widths of greater than 100%. The “Wrong Way” bridge in Cambridge was assigned a low priority for replacement because it had a percent channel width of 180% and there were no signs of its impact on the river.

Table 5. Lamoille River from Johnson to Cambridge Stream Crossing Structures Reach/ Structure No. Structure Road % Phase 2 Notes Priority for Segment Type Name/ Channel Replacement No. Location Width

R08 200030002008022 Bridge Route 15 180 Flooding reported in Low vicinity of bridge; known locally as the “wrong way” bridge. High degree of bank erosion. R08 200030002108022 Bridge Route 15 105 Some deposition NR upstream; newer bridge in good condition R08 200027002108022 Bridge Route 108 100 Deposition and scour NR upstream, none downstream. Bridge replaced in 2014 R09 100802002908021 Bridge Cambridge 72 Deposition and scour Low Junction Rd upstream, historic covered bridge, recently renovated. R09 700000000108023 Bridge LVRT 92 Upstream scour, Plans for Bridge downstream replacement deposition. currently underway R13 200030003308062 Bridge Vermont 135 Deposition upstream NR Route 15 and downstream; new west of bridge, good Johnson condition; sharp bend near Hogback at downstream side Road NR1 : Structure not recommended for replacement.

River Corridor Plan Page 25 Lamoille River from Johnson to Cambridge Lamoille County Planning Commission 6.0 Stressor, Departure and Sensitivity Analysis

Stressor, departure and sensitivity maps are presented here as a means of displaying the effects of all significant physical processes occurring within the Lamoille River stream network from Johnson to Cambridge that were observed during the Phase 1 and Phase 2 Stream Geomorphic Assessments. These maps also provide an indication of the degree to which the channel adjustment processes within the watershed have been altered, at both the watershed scale and the reach scale. The analysis of existing and historic departures from equilibrium conditions along a stream network allows for the prediction of future alterations within the watershed. This is helpful in developing and prioritizing potential protection and restoration projects.

6.1 Departure Analysis and Stressor Identification

6.1.1 Hydrologic Regime Stressors

The hydrologic regime is the timing, volume, and duration of flow events throughout the year and over time and is characterized by the input and manipulation of water at the watershed scale. When the hydrologic regime has been significantly changed, stream channels will respond by undergoing a series of channel adjustments. The land use within the watershed plays a role in the hydrology of the receiving waters. The percentage of urban and cropland development within the watershed are factors which change a watershed’s response to precipitation. The most common effects of urban and cropland development are increasing peak discharges and runoff by reducing infiltration and travel time (United States Department of Agriculture, 1986).

The dominant watershed land cover/land use within the Lamoille watershed is forest. Only one of the 10 reaches within the study area, R13, resulted in a watershed land cover/land use impact rating of high (10% or more is crop and/or urban). Analysis of hydric soils located where current land uses are agricultural or urban indicates some minor loss of wetland attenuation. Historical deforestation in the study area may also have contributed to historic incision.

The study area has a modest network of roads as shown on page 1 of Appendix 2. Stormwater inputs within the Lamoille River watershed are mapped on page 2 of Appendix 2. Extensive road networks can contribute significantly to increased flows within a river resulting both from increased runoff and stormwater ditching. According to Foreman and Alexander (1998), increased peak flows in streams may be evident at road densities of 3.2 miles/ square mile. Five of the 6 subwatersheds in the study area have road densities less than 3.0 miles/square mile, while one (R09) has road densities greater than 3.0 miles/square mile.

6.1.2 Sediment Regime Stressors

The sediment regime is the quantity, size, transport, sorting and distribution of sediments. The sediment regime may be influenced by the proximity of sediment sources, the hydrologic regime, and the specific morphology of the valley, floodplain, and stream. The Sediment Load Indicators Map (Page 3 of Appendix 2) shows the

River Corridor Plan Page 26 Lamoille River from Johnson to Cambridge Lamoille County Planning Commission distribution of sediment load indicators in the Lamoille River watershed from Johnson to Cambridge at the watershed scale. Mass wasting sites were identified during the Stream Geomorphic Assessments in segments R-11 and R-13. Localized areas of bank erosion and depositional features (steep riffles, mid channel bars, delta bars, flood chutes, and/or avulsions) are prevalent. The concentration of depositional features increases in the further downstream reaches.

6.1.3 Reach Scale Sediment Regime Stressors

The previously discussed alterations to flow and sediment load at the watershed scale serve as a pretext for understanding the timing and degree to which reach scale modifications are contributing to field observed channel adjustment. When the valley, floodplain, channel and channel boundary conditions are modified, a stream may change the way sediment is transported, sorted, stored and distributed. The stressors that alter these conditions either increase or decrease stream power and or increase or decrease the resistance of its boundary conditions. This is helpful for determining why a reach is under adjustment and what types of management activities will be beneficial in returning the stream to equilibrium conditions. The primary stressors in each segment of the study area are identified in Table 6. Increases in stream power are represented in Table 6 with bold print, while plain text is used for decreases. The stressors were given a rating of moderate, high and extreme (see legend at bottom or table).

Table 6. Lamoille River from Johnson to Cambridge Hydrologic and Sediment Load Stressors Watershed Input Stressors Reach Modification Stressors Boundary Stream Power Resistance River Bold=increase Bold=increase Segment Hydrologic Sediment load Plain=decrease Plain=decrease Historic Degradation Reduced riparian Erosion (H) Straightening (H) vegetation (H) R08 Wetland loss Depositional Features (H) Encroachment (H) Armoring (H) Historic Degradation Reduced riparian Wetland loss Depositional Features (M) Straightening (H) vegetation (E) R09 A Road Density Erosion (H) Encroachment (H) Armoring (H)

Historic Degradation Reduced riparian Erosion (H) Straightening (M) vegetation (H) R10 D Wetland loss Depositional Features (M) Encroachment (H) Armoring (H)

Historic Degradation Reduced riparian Depositional Features Straightening (H) vegetation (H) R11 C Wetland loss Erosion (H) Encroachment (H) Armoring (H)

Natural Grade R12 B Not assessed Not assessed Control Not assessed

River Corridor Plan Page 27 Lamoille River from Johnson to Cambridge Lamoille County Planning Commission Table 6. Lamoille River from Johnson to Cambridge Hydrologic and Sediment Load Stressors Watershed Input Stressors Reach Modification Stressors Boundary Stream Power Resistance River Bold=increase Bold=increase Segment Hydrologic Sediment load Plain=decrease Plain=decrease

Historic Degradation Reduced riparian Depositional Features Straightening (H) vegetation (E) R13 A Wetland loss Erosion (H) Encroachment (H) Armoring (M) * Shading indicates segment was not assessed during Phase 2 assessment

M = Moderate  Stormwater Inputs and Depositional Features 2-5 per mile; Road Density 3-4 mi/sq. mi.  Straightening, Bank Armoring, Erosion, and Encroachment 5-20%  Urban 5-10%; Reduced Riparian Buffer 5-20% H = High  Stormwater Inputs and Depositional Features >5 per mile; Road Density 5-6 mi/sq. mi.  Straightening, Bank Armoring, Erosion, and Encroachment >20%  Urban 10-20%; Reduced Riparian Buffer 20-50% E = Extreme  Reduced Riparian Buffer >50%; Urban >20%

Primary stressors increasing the sediment load include erosion and reduced riparian vegetation (causing further erosion). This leads to deposition of sediment loads downstream. A high degree of straightening and armoring increase the stream’s energy, leading to further erosion. Multiple encroachments such as roads and development are exacerbating the impacts, as they often require armoring for protection.

6.1.4 Channel Slope Modifiers

Results from the Lamoille River watershed from Johnson to Cambridge indicate that primary stressors include extensive straightening of the channel along with road crossings and encroachments (see Channel Slope Modifiers map on page 4 of Appendix 2). The majority of the channel straightening within the study area was associated with Route 15 and the Lamoille Valley Railroad, both of which run parallel to the river, and farm fields within the river corridor.

Although there is no documented gravel mining and dredging of the channel within any of the assessed reaches, it is likely that some dredging may have occurred during the straightening process in areas where the channel has been modified.

6.1.5 Boundary Conditions and Riparian Modifiers

Riparian buffers provide many benefits. Some of these benefits are protecting and enhancing water quality, providing fish and wildlife habitat, providing streamside shading, and providing root structure to prevent bank erosion. Two stream segments, R10 and R11 had over 70 percent of the reach with little or no buffer on at least one bank. Most

River Corridor Plan Page 28 Lamoille River from Johnson to Cambridge Lamoille County Planning Commission other segments had intermittent locations with riparian buffers less than 25 feet. These stream reaches which lack a high quality riparian buffer are at a significantly higher risk of experiencing high rates of lateral erosion.

6.1.6 Constraints to Sediment Transport and Attenuation

Successful river corridor restoration and protection projects depend on a thorough understanding of the sources, volumes, and attenuation of flood flows and sediment loads within the stream network. If increased loads are transported through the network to a sensitive reach, where conflicts with human investments are creating a management expectation, little success can be expected unless the restoration design accommodates the increased load or finds a way to attenuate the loads upstream (Vermont Agency of Natural Resources, 2007a).

Within a reach, the principles of stream equilibrium dictate that stream power and sediment will tend to distribute evenly over time (Leopold, 1994). Changes or modifications to watershed inputs and hydraulic geometry create disequilibrium and lead to an uneven distribution of power and sediment. Large channel adjustments observed as dramatic erosion and deposition may be the result of this uneven distribution and may continue.

The sediment regime departure map (Page 6 of Appendix 2) shows the Phase 1 reference stream sediment conditions for each reach within the stream network. These reference type streams use available floodplain access as a means to store sediment within the watershed. The majority of the stream network has a reference sediment regime of a Coarse Equilibrium (in=out) & Fine Deposition. The bedrock dominated reaches generally have a Transport sediment regime.

Changes in hydrology (such as development and agriculture within the riparian corridor) and sediment storage within the watershed have altered the reference sediment regime types for some reach segments. Two segments (R10 and R13) that were Coarse Equilibrium (in=out) & Fine Deposition type segments by reference have been converted to Fine Source and Transport & Coarse Deposition sediment regimes based on the Phase 2 Stream Geomorphic Assessment data. Fine sediment entering the stream is being transported through without being deposited as a result of channel incision and reduced floodplain access. Additionally coarse sediment storage is increased due to increased load along with lower transport capacity. One segment (R09) that was Coarse Equilibrium (in=out) & Fine Deposition by reference has been converted to an Unconfined Source and Transport sediment regime from increased sediment supply due to extreme incision and resultant widening and planform adjustment. All departures were derived from the DMS according to the sediment regime criteria established by the Vermont Agency of Natural Resources (2007a) (see Table 7 below).

The existing sediment regime for the Lamoille River watershed from Johnson to Cambridge includes reduced floodplain access, increased stream power, reduced boundary resistance, and lateral constraints at various locations throughout the stream network. Watersheds which have lost attenuation or sediment storage areas, due to human related constraints, are generally more sensitive to erosion hazards, transport

River Corridor Plan Page 29 Lamoille River from Johnson to Cambridge Lamoille County Planning Commission greater quantities of sediment and nutrients to receiving waters, and lack the sediment storage and distribution processes that create and maintain habitat (Vermont Agency of Natural Resources, 2007a). Segments and reaches of the study area that can act as attenuation assets are identified below under “Preliminary Project Identification and Prioritization” to help in designing stream corridor protection and restoration projects within the stream network.

Table 7: Sediment regime types for corridor planning (VTANR, 2010). Sediment Narrative Description Regime Steeper bedrock and boulder/cobble cascade and step-pool stream types; typically in more confined valleys, do not supply appreciable quantities of sediments to downstream reaches on an annual basis; little Transport or no mass wasting; storage of fine sediment is negligible due to high transport capacity derived from both the high gradient and/natural entrenchment of the channel. Cobble step pool and steep plane bed streams; confining valley walls, comprised of erodible tills, glacial lacustrine, glacial fluvial, or alluvial materials; mass wasting and landslides common and may be triggered by Confined valley rejuvenation processes; storage of coarse or fine sediment is limited due to high transport capacity Source and derived from both the gradient and entrenchment of the channel. Look for streams in narrow valleys Transport where dams, culverts, encroachment (roads, houses, etc.), and subsequent channel management may trigger incision, rejuvenation, and mass wasting processes. Sand, gravel, or cobble plane bed streams; at least one side of the channel is unconfined by valley walls; may represent a stream type departure due to entrenchment or incision and associated bed form changes; these streams are not a significant sediment supply due to boundary resistance such as bank armoring, but Unconfined may begin to experience erosion and supply both coarse and fine sediment when bank failure lead to Source and channel widening; storage of coarse or fine sediment is negligible due to high transport capacity derived Transport from the deep incision and little or no floodplain access. Look for straightened, incised or entrenched streams in unconfined valleys, which may have been bermed and extensively armored and are in Stage II or early Stage III of channel evolution. Sand, gravel, or cobble streams with variable bed forms; at least one side of the channel is unconfined by valley walls; may represent a stream type departure due to vertical profile and associated bed form Fine Source and changes; these streams supply both coarse and fine sediments due to little or no boundary resistance; Transport storage of fine sediment is lost or severely limited as a result of channel incision and little or no floodplain & access; an increase in coarse sediment storage occurs due to a high coarse sediment load coupled with the Coarse lower transport capacity that results from a lower gradient and/or channel depth. Look for historically Deposition straightened, incised, or entrenched streams in unconfined valleys, having little or no boundary resistance, increased bank erosion, and large unvegetated bars. These streams are typically in late Stage III and Stage IV of channel evolution. Sand, gravel, or cobble streams with equilibrium bedforms; at least one side of the channel is unconfined Coarse by valley walls; these streams transport and deposit coarse sediment in equilibrium (stream power— Equilibrium (in = produce as a result of channel gradient and hydraulic radius—is balanced by the sediment load, sediment out) size, and channel boundary resistance); and store a relatively large volume of fine sediment due to the & access of high frequency (annual) floods to the floodplain. Look for unconfined streams, which are not Fine Deposition incised or entrenched, have boundary resistance (woody buffers), minimal bank erosion, and vegetated bars. These streams are Stage I, late IV, and Stage V. Silt, sand, gravel, or cobble streams with variable and braided bed forms; at least one side of the channel is unconfined by valley walls; may represent a stream type departure due to changes in slope and/or depth resulting in the predominance of transient depositional features; storage of fine and coarse sediment frequently exceeds transport**. Floodplains are accessed during high frequency (annual) floods. Look for Deposition unconfined streams, which are not incised or entrenched, have become significantly over-widened, and if high rates of bank erosion are present, it is offset by the vertical growth of unvegetated bars. These regimes may be located at zones of naturally high deposition (e.g., active alluvial fans, deltas, or upstream of bedrock controls), or may exist due to impoundment and other backwater conditions above weirs dams and other constrictions. ** Use of the “Deposition” regime characterization may be rare, but valuable as a planning tool, where the reach is storing far more than it is transporting during some defined planning period. The extreme example would be that of an impounded reach where all of the coarse sediments and a great percentage of the fine sediments are being deposited, rather than transported downstream. This man-made condition may change, thereby changing the sediment regime, but is not likely over the period at which the corridor plan will be used.

River Corridor Plan Page 30 Lamoille River from Johnson to Cambridge Lamoille County Planning Commission 6.2 Sensitivity Analysis

Stream sensitivity refers to the likelihood that a stream will respond to a watershed or local disturbance or stressor, such as; floodplain encroachment, channel straightening or armoring, changes in sediment or flow inputs, and/or disturbance of riparian vegetation (Vermont Agency of Natural Resources, 2007b).

Assigning a sensitivity rating to a stream is done with the assumption that some streams, due to their setting and location within the watershed, are more likely to be in an episodic, rapid, and/or measurable state of change or adjustment. A stream’s inherent sensitivity may be heightened when human activities alter the setting characteristics that influence a stream’s natural adjustment rate including: boundary conditions; sediment and flow regimes; and the degree of confinement within the valley. Streams that are currently in adjustment, especially those undergoing degradation or aggradation, may become acutely sensitive (Vermont Agency of Natural Resources, 2007b).

There are many variables that are contributing to the sensitivity of the streams in the Lamoille River watershed from Johnson to Cambridge. The existing geomorphic condition and stream sensitivity of the Phase 2 assessed reaches are presented in Table 8.

Table 8. Stream Sensitivity for Phase 2 Reaches

Segment Reference Existing Stream Geomorphic Sensitivity Number Stream Stream Type Condition Type Type Departure R13 C4 F4 Yes Fair Extreme R12 Not Evaluated – Bedrock R11 C4 C4 No Fair Very High R10 C4 C4 No Poor Very High R09 C4 C5 Yes Fair Very High R08 C4 C4 No Fair Very High

The location and slope of a stream also affects its morphology and sensitivity. Streams that are transporting sediment through the channel are less sensitive than streams that are storing and responding to sediment. Additionally, flow regime and floodplain constrictions may be affecting the sensitivity of the study area. Changes in land use and land cover that increase impervious cover, peak discharges, and/or the frequency of high flows will heighten a stream’s sensitivity to change and adjustment. Confinement becomes a significant sensitivity concern when structures such as roads, railroads, and berms significantly change the confinement ratio, reduce or restrict a stream’s access to floodplain, and result in higher stream power during flood stage. The map on page 7 of Appendix 2 presents the stream sensitivity, generalized according to stream type and condition as per the VANR protocol, and current adjustments for each reach segment in the Lamoille River watershed from Johnson to Cambridge. Sensitivity ratings have not been assigned for segments that were not fully assessed during the Phase 2 study.

River Corridor Plan Page 31 Lamoille River from Johnson to Cambridge Lamoille County Planning Commission The stream sensitivity map also documents vertical channel adjustments currently going on within a reach segment. Degradation or aggradation adjustment processes are displayed on the sensitivity corridors where they were found to be actively occurring and they were not evaluated as historic. This information is helpful in prioritizing the implementation of the projects identified in section 7 of this report, as certain management actions may be influenced by these active adjustment processes. While aggradation is seen in all assessed reaches, it was noted as the major adjustment process in five of six reaches.

Table 9: Major Vertical Adjustment Process Segment ID Current Major Adjustment Process R13 Aggradation R12 No aggradation, bedrock R11 Aggradation R10 Aggradation R09 No Major Vertical Adjustment. Major Widening and Planform Adjustment noted R08 Aggradation

7.0 PRELIMINARY PROJECT IDENTIFICATION AND PRIORITIZATION

The departure and sensitivity analyses presented in Section 6.0 of this report provide beneficial background for selecting potential projects that will effectively help the channel return to equilibrium conditions by assessing limiting factors and by identifying underlying causes of channel instability. The stream reaches evaluated in this study present a variety of planning and management strategies which can be classified under one of the following categories: Active Geomorphic Restoration, Passive Geomorphic Restoration, and Conservation.

Active Geomorphic Restoration implies the management of rivers to a state of geomorphic equilibrium through active, physical alteration of the channel and/or floodplain. Often this approach involves the removal or reduction of human constructed constraints or the construction of meanders, floodplains or stable banks. Active riparian buffer revegetation and long-term protection of a river corridor is essential to this alternative.

Passive Geomorphic Restoration allows rivers to return to a state of geomorphic equilibrium by removing factors adversely impacting the river and subsequently using the river’s own energy and watershed inputs to re-establish its meanders, floodplains and equilibrium conditions. In many cases, passive restoration projects may require varying degrees of active measures to achieve the ideal results. Active riparian buffer revegetation and long-term protection of a river corridor is also essential to this alternative.

Conservation is an option to consider when stream conditions are generally good and nearing a state of dynamic equilibrium. Typically, conservation is applied to minimally disturbed stream reaches where river structure and function and vegetation associations are relatively intact.

River Corridor Plan Page 32 Lamoille River from Johnson to Cambridge Lamoille County Planning Commission

There are a number of voluntary programs available for river protection. Two of the primary programs are the Conservation Reserve Enhancement Program (CREP) and the River Corridor Easement (RCE). CREP is a program that helps protect environmentally sensitive land, decrease erosion, and restore wildlife habitat by taking land out of agricultural production. An overview of the Conservation Reserve Enhancement Program is found at http://www.fsa.usda.gov/FSA/webapp?area=home&subject=lown&topic=cep. The River Corridor Easement is designed to promote the long term physical stability of the river by allowing the river to achieve a state of equilibrium (where sediment and water loads are in balance). River corridor easements are vital for a passive geomorphic restoration approach and can also be used for conserving rivers that are in good condition (equilibrium). Rivers that are in equilibrium have access to their floodplains and therefore experience less erosion and negative impacts from flooding events. A description of each of the programs prepared by the Vermont River Management Program is provided below.

Conservation Reserve Enhancement Program  CREP can be either a 15 or 30-year contract to plant trees.  90% of the practice costs are covered with the remaining 10% either resting with the participants or could be paid by the US Partners for Fish and Wildlife. Examples of the practice costs include fencing, watering facilities, and trees. There are some costs that are capped, but generally all the practice costs can be paid through the program.  To provide additional incentives to enroll in CREP, the program offers upfront and annual rental payments for the land where agricultural production is lost during the contract period.

River Corridor Easement (RCE)  Easements are in perpetuity, meaning the agreement stays with the land forever.  A onetime payment is received by the landowner for transferal of channel management rights to a second party (a land trust).  Transferal of channel management rights means that the landowner would no longer be able to rock line river banks or remove gravel for personal use.  A RCE requires a minimum 50-foot buffer that floats with the river. No active land use is allowed within the buffer. The buffer can be actively planted or allowed to revegetate passively.  The easement does not take away the agricultural land use rights, so the landowner could continue to crop or pasture the farm land mapped outside of the buffer, yet within the corridor, for as long as the river allows.

7.1Watershed-Level Opportunities

River Corridors

Of all types of natural hazards experienced in Vermont, flash flooding represents the most frequent disaster mode and has resulted in by far the greatest magnitude of damage suffered by private property and public infrastructure. While inundation-related flood loss is a significant component of flood disasters, the predominant mode of damage is associated

River Corridor Plan Page 33 Lamoille River from Johnson to Cambridge Lamoille County Planning Commission with the dynamic, and oftentimes catastrophic, physical adjustment of stream channel dimensions and location during storm events due to bed and bank erosion, debris and ice jams, structural failures, flow diversion, or flow modification by man-made structures. These channel adjustments and their devastating consequences have frequently been documented wherein such adjustments are related to historic channel management activities, floodplain encroachments, adjacent land use practices and/or changes to watershed hydrology associated with land use and drainage.

Towns can reduce flood recovery and infrastructure maintenance costs and increase public safety by limiting development in areas adjacent to rivers with a high potential for vertical and lateral adjustment. The River Corridor zone can be thought of as the corridor a river or stream requires to redevelop or maintain equilibrium conditions over the long term. River Corridor zones also indicate which reaches have a higher propensity for severe migration during flood events. These reaches, which are given elevated ratings of “very high” or “extreme”, are high priority reaches for protection, especially when there is little existing protection afforded by wetlands or conservation easements.

The purpose of defining River Corridor zones is to minimize or prevent repeated damages to development due to fluvial erosion; and prohibit land uses and development in areas that pose a danger to health and safety. A River Corridor includes the course of a river and its adjacent lands. The width of the corridor is defined by the lateral extent of the river meanders, called the meander belt width, which is governed by valley landforms, surficial geology, and the length and slope requirements of the river channel. The width of the corridor is also governed by the stream type and sensitivity of the stream. River corridors, as defined by the Vermont Agency of Natural Resources (2008), are intended to provide landowners, land use planners, and river managers with a meander belt width which would accommodate the meanders and slope of a balanced or equilibrium channel, which when achieved, would serve to maximize channel stability and minimize fluvial erosion hazards. Information collected during the Phase 2 Assessment including reach sensitivity, reach condition, and stream type is used to develop these areas.

In January 2015, the Vermont Agency of Natural Resources published a statewide river corridors layer for the purposes of regulating development along rivers and streams for development under Act 250 or Section 248 jurisdiction. Towns have the opportunity to work with the Vermont River Management Program to further refine this layer and adopt all or portions of it to reduce conflicts within the river corridor.

Stormwater

Stormwater runoff rates are of particular concern in urbanized and agricultural watersheds because stormwater runs off from impervious surfaces rather than naturally infiltrating the soil. The cumulative effect of the increased frequency, volume, and rate of stormwater runoff results in increases in wash-off pollutant loading to streams and destabilization of stream channels. All potential restoration projects within the Lamoille watershed should be evaluated in terms of their effects on stormwater. Green Stormwater Infrastructure projects should be implemented in communities to reduce the effect of stormwater runoff on the Lamoille River.

River Corridor Plan Page 34 Lamoille River from Johnson to Cambridge Lamoille County Planning Commission 7.2 Reach-Level Opportunities

A description of each reach/segment is provided in this section along with general recommendations for restoration and protection strategies. Projects within the River Corridor Plan will be used in the Lamoille Tactical Basin Planning process to help determine where there may be opportunities and needs for project level work. As additional data and/or information is obtained on these reaches over time; project opportunities and needs may be updated. The reaches are listed from upstream to downstream. Further details about project types for each reach will be discussed in Section 7.3.

Lamoille River from Johnson to Cambridge (R13-R08)

Reach R13 Conservation Improve Riparian Buffer CREP

Lamoille River reach R13 begins in Johnson Village at the mouth of the Gihon River and flows downstream to where the valley confinement changes just above Ithiel Falls. Similar to the upstream segment R14-A, this reach has undergone significant channel straightening and historic channel degradation. The result is a floodplain elevation that is twice the bankfull height (incision ratio of 2.0). The loss of floodplain access along this reach has caused a stream type departure from a reference “C” channel to an existing “F” channel. As a result of these changes, the channel is currently undergoing major aggradation, widening, and planform adjustment in an attempt to redevelop a new floodplain at a lower elevation. Armoring and erosion were mapped along nearly 50% of each streambank.

River Corridor Plan Page 35 Lamoille River from Johnson to Cambridge Lamoille County Planning Commission

Figure 9: Reach R13 has undergone significant channel straightening and historic channel degradation.

Figure 10: R13-A has undergone historic channel degradation. Channel incision is evident downstream of Route 15 Bridge in Johnson.

River Corridor Plan Page 36 Lamoille River from Johnson to Cambridge Lamoille County Planning Commission Hay fields, crops and some residential development were noted as the dominant land uses within the riparian corridor. The buffer was highly disturbed on both sides with herbaceous vegetation as the dominant vegetation type. There are a number of programs available, such as CREP (see Section 7.0), which are available for landowners to expand the riparian buffer in an effort to improve water quality.

Plantings or riparian buffer regeneration are recommended in this reach to improve the riparian buffer. However, given the extreme historic incision and active major widening, plantings along the near bank are not recommended. Rather, plantings should take place back from the river bank and should be in areas that are not prone to active erosion.

There is a large tract of conserved land owned by the Town of Johnson in the upper part of the reach along the south bank of the Lamoille. The portion of land adjacent to the river is a mixture of recreational and industrial uses. This offers an opportunity for the Town to consider a river corridor easement for a portion of this conserved land, in order to allow the river some space to reestablish a new floodplain.

Reach R12 Conservation Improve Riparian Buffer Hogback Road Corridor Mitigation

Lamoille River reach R12 begins upstream from Ithiel Falls, west of Johnson Village, and continues for 6,114 feet to where the bedrock influenced channel again becomes a very broad alluvial valley. This reach was only partially assessed due to the significant influence of bedrock on the stream channel. Riparian buffer encroachment has occurred on the north side of the channel where Hogback Road borders the river. A series of bedrock channel constrictions is causing localized aggradation and adjustment, while at the same time lending to the long term stability of the channel through this reach.

River Corridor Plan Page 37 Lamoille River from Johnson to Cambridge Lamoille County Planning Commission

Figure 11: Bedrock channel constriction Hogback Road, within and adjacent to the Lamoille River floodplain, often sees water overtop in certain areas. There are several sections of Hogback that are close to the river and many of these sections have been armored over the years. Currently erosion is occurring upstream and downstream of adjacent riprap. The Town has recognized that they are in a cyclical pattern of repeatedly armoring eroded sections of streambank, and it might be worthwhile to employ a corridor planning approach (of river and roadway) to scope out short and long term mitigation solutions. An example of a long-term approach is to acquire the right-of-way to relocate roadway outside of the river corridor.

Currently almost 1/3 of the reach’s river corridors are within Long Trail State Forest conserved lands. Because this reach is in fairly stable condition, it would be beneficial to consider opportunities to conserve additional forested land along this reach. LCPC recommends that the Town work with partners such as the Vermont Rivers Conservancy and/or the Vermont Land Trust to scope out other conservation opportunities. Most of this reach is forested; however there is one small hayfield just downstream of the R13 reach break. The riparian buffer could be improved with additional plantings or allow the buffer to regenerate naturally here.

Reach R11 Conservation Improve Riparian Buffer CREP

Lamoille River reach R11 begins at end of the bedrock influence reach near Ithiel Falls and flows downstream through a very broad alluvial valley to the mouth of the North Branch of

River Corridor Plan Page 38 Lamoille River from Johnson to Cambridge Lamoille County Planning Commission the Lamoille River in the Town of Cambridge (east of Jeffersonville). The alluvial valley has been narrowed by the building of the railway, Route 15 and Route 109. Additionally, much of the riparian vegetation of this reach has been removed or significantly altered. Despite this changes to the Lamoille floodplain, the river has remained a “C” type gravel dominated channel with a riffle-pool bedform. Like many of the Lamoille River’s reaches, the bankfull elevation of this reach was also observed to be below the top of the streambank, indicating that some degree of channel incision has occurred (incision ratio of this reach 1.3) This incision is being followed by current existing major channel aggradation, planform adjustment, and minor channel widening as the river works to develop accessible floodplain.

Figure 12: Rip rap at toe of bank, with willow planted on top.

River Corridor Plan Page 39 Lamoille River from Johnson to Cambridge Lamoille County Planning Commission

Figure 13: Erosion and disturbance to riparian buffer.

For most of this reach the predominant land use is agricultural with only a few encroachments such as one location where the Lamoille Valley Rail Corridor abuts the river and two locations where Hogback road encroaches the river corridor. In 2007 two projects were completed along this reach to lower portions of the Lamoille Valley Rail to allow for increased floodplain access. The projects were supported by the landowners, Town of Cambridge, VTrans, LCPC, Lamoille County Conservation District, and VT ANR Rivers Program. Eighty-nine acres of floodplain access were restored as part of these efforts. If this type of land use is maintained, and residential and commercial development near the river discouraged, it will provide the Lamoille River enough room to develop adequate floodplain and to reach a dynamic equilibrium without threatening infrastructure. There is currently approximately 200 acres of farmland adjacent to the south side of the Lamoille that is conserved by the Vermont Land Trust through conservation easements in this reach. The LCPC and Towns of Cambridge and Johnson should work with the Vermont Land Trust and adjoining landowners to conserve other portions of farmland along R11. On the downstream end on the northern side of R11, there is currently an effort underway for a conservation easement with Vermont Land Trust.

Much of the riparian buffer in this reach was highly disturbed. Because this reach is not highly incised and since the agricultural uses are compatible, there are opportunities to improve the riparian buffer with passive regeneration or active planting through programs like CREP or Trees for Streams. There may also be opportunities to restore floodplain access in strategic locations. In conjunction with or separately from conservation, the LCPC should work with the Lamoille Basin Planner, Vermont Rivers Program, Lamoille County

River Corridor Plan Page 40 Lamoille River from Johnson to Cambridge Lamoille County Planning Commission Conservation District and adjoining landowners to further scope out appropriate sites for riparian improvement projects.

Reach R10 Conservation Improve Riparian Buffer

Lamoille River reach R10 begins at the mouth of the North Branch and continues downstream to a point east of Jeffersonville where the river becomes more confined. In this reach the channel slope of the Lamoille flattens, the substrate becomes dominated by fine gravel and sand particles, and the bedform changes into a ripple-dune system. A measured bankfull below the top of the riverbank indicated historic channel incision has also occurred in this reach. Major channel aggradation, and planform adjustment as well as minor widening are resulting from this historic incision. Several old oxbows were observed in the floodplain of this reach and are indicators of historic planform adjustment and possibly straightening associated with agriculture.

Figure 14: Cross section illustrating historic incision of this reach.

Although there is little development on the north side of the Lamoille in this reach, it is confined on the south side by the encroaching Rail Trail and Route 15. Because of this, it will be important to conserve as much farmland on the north side as possible and to limit development in the floodplain. As with Reach R11, LCPC and Town of Cambridge should

River Corridor Plan Page 41 Lamoille River from Johnson to Cambridge Lamoille County Planning Commission work with the Vermont Land Trust and adjoining landowners to conserve farmland along the reach; as well as looking at possible floodplain bylaws to prevent future development.

The riparian buffer is in relatively good condition along a majority of this reach; however, there is one location along the outside of a large meander bend just upstream of R10 reach break where riparian regeneration might be warranted. The LCPC should work with the Lamoille Basin Planner, Vermont Rivers Program, Lamoille County Conservation District and adjoining landowners to further scope out appropriate sites for buffer plantings.

Reach R09 Replace/Retrofit Bridge Floodplain Restoration

Lamoille River reach R09 begins where the river becomes more confined east of Cambridge Junction Road Bridge (Poland Covered Bridge) and continues to the mouth of the Brewster River, near the Route 108 truss bridge in Cambridge. Here the river continues to remain at a low slope with a sand dominated riffle-dune bedform. Incision along this reach is considerable (1.8), and is leading to a high level of widening, and planform adjustment as well as having many depositional features present. The channel evolution is currently in Stage III heading towards IV in areas where it has redeveloped floodplain.

Figure 15: Poland Covered Bridge

River Corridor Plan Page 42 Lamoille River from Johnson to Cambridge Lamoille County Planning Commission In this reach there is little development within the river corridor on the north side of the Lamoille and the land use is primarily agricultural; on the south side there is some residential development along with hayfields and a recreational Rail Trail. Current agricultural and compatible recreational uses should be encouraged, and future trailheads should be developed so as to minimize or avoid encroachment on the river. Trailhead construction plans are currently underway on the south side of the Poland Covered Bridge. On the north side of the river by the covered bridge, there may be an opportunity for future floodplain restoration and development of a canoe access with collaboration of the landowner and the Lamoille River Paddler’s Trail. Re-sloping of the bank and placement of soft stabilization methods such as tree revetments would help to restore the floodplain and protect the streambank from erosion. If a paddler’s access point is developed on the north side of the Lamoille, it should avoid any development within the floodplain and minimize development in the river corridor. These type of projects can be explored with the Lamoille Bain Planner, LCPC, and VT Rivers Program. The Poland Covered Bridge was renovated in 2015 and further retrofit/renovation is not in the plans for the near future.

Downstream of the Poland Covered Bridge are the remnants of a rail bridge that during this assessment was still intact. The bridge opening was 92% of bankfull, and it was assigned as a moderate priority for replacement as it was causing some localized instability. In the winter of 2015-2016, ice jams knocked down wooden piers supporting one side of the railroad bridge. Due to the damage and development of the Lamoille Valley Rail Trail, VAST in cooperation with VTrans has plans to replace and retrofit the bridge.

Figure 16: Railroad Bridge prior to 2015-2016 damage.

River Corridor Plan Page 43 Lamoille River from Johnson to Cambridge Lamoille County Planning Commission

Reach R08 Conservation Floodplain Restoration Improve Riparian Buffer

Lamoille River reach R08 begins at the mouth of the Brewster River and flows downstream to the “wrong-way” bridge in Cambridge and the end of the study area included in this report. Here the channel once again becomes dominated by gravel substrates and a riffle pool bedform. The channel remains a reference “C” type, however, historic channel incision has led to major channel widening, aggradation, and planform adjustment. This reach was noted as having a weak riffle pool bedform. Several areas of floodplain access exist and several flood chutes were noted.

Figure 17: Large point bar illustrating the process of aggradation and widening.

River Corridor Plan Page 44 Lamoille River from Johnson to Cambridge Lamoille County Planning Commission

Figure 18: Floodplain forest showing one location with floodplain access.

Immediately downstream of the R09 reach break the Lamoille River flows through the Village of Jeffersonville. The confluence of the Lamoille and the Brewster River is a highly sensitive location with a history of flooding. In recent years, as storms have grown in frequency and intensity, major flood events have become more common and more damaging. Heavy rain storms, tropical storms, and seasonal snow melts from the surrounding mountain slopes causing the Lamoille and Brewster Rivers to overflow, topping their banks and flooding the village of Jeffersonville.

River Corridor Plan Page 45 Lamoille River from Johnson to Cambridge Lamoille County Planning Commission

Figure 19: Major flood event in Jeffersonville, April 2011.

In response to repeated flood damages, the Village of Jeffersonville and Town of Cambridge have focused their efforts on exploring flood mitigation options, outlined as follows:

 In 2011, Jeffersonville adopted more stringent flood hazard regulations, based on the State Model 2, prohibiting future development in the floodplain. The Town and Village of Cambridge have also adopted Flood Hazard Regulations.  In 2011, the Village acquired a grant to purchase the former Jolley property, a 4.2 acre parcel located within the Special Flood Hazard Area formed by the nearby confluence of the Lamoille and Brewster Rivers. Purchase of this property will be a critical component of flood mitigation efforts for the Village, namely ensuring that this large and vulnerable portion of Jeffersonville’s floodplain remains open in perpetuity. The Village is in the process of granting a River Corridor Easement for a portion of this property.  In 2013, Milone and McBroom developed a flood model to explore a number of flood mitigation options for the Village; the Village and Town applied for grant funding to implement some key actions that will reduce flooding and associated damages, including: o Installing large culverts under Route 15 to carry flood waters from the Brewster into the Lamoille; o Replacement of the Cambridge Greenway Trail Bridge with a wider span bridge and restoring adjacent floodplain; and o Flood proofing existing buildings.

River Corridor Plan Page 46 Lamoille River from Johnson to Cambridge Lamoille County Planning Commission Plans are currently underway for the construction of the culverts, trail bridge replacement, and floodplain restoration as part of the Town of Cambridge Flood Mitigation Project. Additionally, through a grant received from the High Meadows fund, LCPC has been working with the communities of Cambridge and Jeffersonville to educate business and landowners in floodproofing vulnerable buildings in the floodplain.

Further development and implementation of these flood mitigation measures should consider potential impacts on the Lamoille and should not exacerbate the river’s instability.

Downstream of Jeffersonville, the Lamoille is confined by Route 15 in several places; however abundant farm fields provide an opportunity for conservation, and a few large hayfields on the south side of the river have been conserved by the Vermont Land Trust. The LCPC should work with the Town, Lamoille Basin Planner, ANR Rivers Program, the Vermont Land Trust and landowners to pursue conservation of additional parcels in the river corridor. There are also a few places where plantings would improve the riparian buffer.

7.3 Previous Site Level Restoration Efforts

As described above in the Reach Level Opportunities (Section 7.2), channels with disconnected floodplains are common along the Lamoille River. A large floodplain restoration project was completed in 2008 along Black Creek and Lamoille River in 2008 (please see Appendix 3 for a description of this restoration work). Six miles of former rail embankment was removed to reconnect over 200 areas of historic floodplain (Summarized in Schiff et al., 2008).

Of the ten sites selected for the restoration project within the Lamoille River study area from Hardwick to Johnson, two areas were completed along Reach M11 (Cambridge 1 and Cambridge 1b) and two others in Wolcott and Johnson (Wolcott 1 and Johnson 1).

7.4 Proposed Site Level Restoration Opportunities

River corridor easements along the Lamoille River would be beneficial for reducing armoring and straightening by transferring channel management rights to a second party (such as a land trust). The inclusion of the entire river corridor zone in a corridor easement is expensive due to the size of the floodplain of the Lamoille River main stem. In areas where land use is in conflict with the Lamoille River main stem, a narrower corridor may be defined as part of a corridor easement. Reaches R13 (Johnson), R11 (Johnson and Cambridge), and R10, R09, and R08 (Cambridge) are areas where planform adjustment has been identified as a major process. Areas with major to extreme planform adjustment are more apt to result in landowner concerns and conflicts with the river. As landowners approach the Agency of Natural Resources with their concerns and questions about armoring stream banks, this provides an opportunity to discuss the possibility of a corridor easement as an alternative.

Site specific projects were identified using the criteria outlined by the VANR in Chapter 6 Preliminary Project Identification and Prioritization (Vermont Agency of Natural Resources,

River Corridor Plan Page 47 Lamoille River from Johnson to Cambridge Lamoille County Planning Commission 2007a). This planning guide is intended to aid in the development of projects that protect and restore river equilibrium. The site level projects that were developed for the Lamoille River from Johnson to Cambridge are provided below in Table 10. The project strategy, technical feasibility, and priority for each project are listed by project number and reach. Maps of the project sites are shown in Figures 20 through 25. Projects include river corridor protection to provide attenuation of sediment and floodwaters through corridor easements, riparian buffer improvement areas, floodplain restoration and the replacement or retrofitting of undersized stream crossing structures. Information from the Phase 2 stream geomorphic assessment and VANR bridge and culvert assessment could be used to inform the Vermont Agency of Transportation and the Towns of Johnson and Cambridge, of which stream crossings are contributing to localized instability.

River Corridor Plan Page 48 Lamoille River from Johnson to Cambridge Lamoille County Planning Commission

Table 10. Lamoille River Site Level Opportunities for Restoration and Protection

Project # Segment Type of Site Description Including Project or Technical Other Social Benefits Costs Land Use Conversion Potential Partners Latitude Longitude Project Stressors and Constraints Strategy Feasibility and (Decimal (Decimal Description Priority Degrees) Degrees) #1 Passive Highly incised channel, currently Protect River Feasible to get town Flood and sediment Cost of corridor None VANR, LCPC, Town of Johnson, In Johnson Village at the mouth Restoration undergoing major aggradation, Corridor buy-in on river attenuation easements for 110 Village of Johnson, VLT, VRC of the Gihon River to just widening, and planform adjustment. through corridor overlay with acres ≈ $190,000 1 above Ithiel Falls. corridor updating state R13 easement or corridor based on 44.63367 -72.69195 adoption of ground truthing of river corridor valley walls. overlay. High priority #2 Active Multiple locations along the Lamoille. Streamside High Priority Reduce erosion, improve Cost of plantings: Hay fields to forested buffer VANR, LCPC, landowner, USFWS, Beginning downstream of Restoration Riparian buffer is narrow and/or plantings or habitat and reduce water $4,500/acre2 LCCD, Johnson Village to the R13 undermined and areas with no buffer buffer temperature 44.63463 -72.70331 reach break just above Ithiel and erosion. regeneration Falls R13 #3 Active One small hayfield just downstream Streamside Moderate Priority Reduce erosion, improve Cost of plantings: Hay fields to forested buffer VANR, LCPC, landowner, USFWS, Begins just above Ithiel Falls Restoration of the R13 reach break. The riparian plantings or habitat and reduce water $4,500/acre LCCD west of Johnson Village and buffer is sparse and there is 300’ of buffer temperature 44.64528 -72.72027 continues for 6114 feet erosion on the left bank regeneration R12 #4 Active Much of the riparian vegetation in this Streamside High Priority Reduce erosion, improve Cost of plantings: Hay fields or crop fields to forested buffer VANR, LCPC, landowner, USFWS, Begins at the end of the Restoration reach has been removed or altered, plantings or habitat and reduce water $4,500/acre LCCD bedrock influenced reach near and bank erosion is prevalent. buffer temperature 44.65074 -72.74390 Ithiel Falls to the mouth of the regeneration North Branch R11 #5 Passive Historic channel incision; current Protect River Conservation Flood and sediment Cost of corridor Corn fields to floodplain VANR, LCPC, landowner, VLT, VRC Begins at the end of the Restoration aggradation and planform adjustment. Corridor Easement Underway attenuation easement for all 398 bedrock influenced reach near through - High Priority cares ≈ $687,000. 1 Ithiel Falls to the mouth of the corridor Sites where RCE is North Branch easement recommended are 44.66589 -72.76575 R11 nearby land already conserved by VLT but easement can continue past this area #6 Active Historic channel incision; current Streamside High Priority Reduce erosion, improve Cost of plantings: Hay fields or crop fields to forested buffer VANR, LCPC, landowner, USFWS, Begins at the mouth of the Restoration aggradation, widening and planform plantings or habitat and reduce water $4,500/acre; Cost of LCCD North Branch and continues to adjustment. As well as potential buffer temperature easement for 145 just east of Jeffersonville where straightening from agriculture regeneration/ acres ≈ $250,000 1 44.66323 -72.80151 the river becomes more conservation confined. easement R10 #7 Active Considerable incision leading to a Tree planting Moderate Flood and sediment Cost of materials for None VANR, LCPC, LRPT, landowner, VLT, Begins east of Poland Covered Restoration high level of aggradation, major or bank attenuation bank stabilization and VRC Bridge and continues to the widening and planform adjustment. resloping with cost of easement for mouth of the Brewster River There is interest from landowner to soft all 207 acres ≈ R09 protect streambank. Landowner stabilization $357,000 1 44.65213 -72.81336 would like community to own and methods (tree manage. Lamoille River Paddlers Trail revetments/vein is a stakeholder due to stream access s). Corridor issues. easement. #8A Active Old railroad bridge is undersized and Replace Bridge Plans for Flood and sediment VTrans funded Unknown VANR, LCPC, VAST, VTRANS Begins east of Cambridge Restoration contributing to instability. Slated for replacement and attenuation Junction covered bridge and replacement by VAST retrofit currently 44.65172 -72.81387 continues to the mouth of the underway Brewster River R09

1 Cost of easement from Vermont Agency of Natural Resources, based on average cost of easements of $1,727 per acre. Range of cost of easements is from $0 (donation) to $4,676 per acre. 2 Cost of tree plantings was estimated from projects by Lamoille County Conservation District

River Corridor Plan Page 49 Lamoille River from Johnson to Cambridge Lamoille County Planning Commission Table 10. Lamoille River Site Level Opportunities for Restoration and Protection

Project # Segment Type of Site Description Including Project or Technical Other Social Benefits Costs Land Use Conversion Potential Partners Latitude Longitude Project Stressors and Constraints Strategy Feasibility and (Decimal (Decimal Description Priority Degrees) Degrees) #8B Active Floodplain completely filled in where Restore Low Priority Flood and sediment Moderate to high Unknown VANR, LCPC, VAST, VTRANS Begins east of Poland Covered Restoration old railroad bridge is – contributing Floodplain attenuation costs of floodplain Bridge and continues to the to geomorphic instability. Railbed restoration 44.65098 -72.81457 mouth of the Brewster River removal not a priority for community R09 due to presence of buildings #9A Active Trail bridge near the confluence of Replace bridge Plans for trail bridge Flood and sediment FEMA funded Unknown VANR, LCPC, FEMA, Town of Begins at the mouth of the restoration the Brewster and Lamoille Rivers is with higher and reconstruction attenuation Cambridge, Village of Jeffersonville Brewster River and continues undersized and blocks the flow of the longer span currently underway; to the “Wrong Way” bridge in Brewster during high flows, causing bridge to allow High priority Cambridge Village. water to back up and flood into the for greater 44.64370 -72.85856 R08 Village channel capacity, which will reduce flooding in the Village #9B Active Floodplain around the existing Trail Remove fill and Floodplain Flood and sediment Part of bridge Unknown VANR, LCPC, FEMA, Town of Begins at the mouth of the Restoration Bridge has been completely filled in restore channel restoration currently attenuation replacement, Cambridge, Village of Jeffersonville Brewster River and continues on both sides of the structure and an width and underway as part of floodplain restoration to the “Wrong Way” bridge in earthen berm exists from the former floodplain as the Trail bridge piece is ERP funded 44.64141 -72.84448 Cambridge Village. Rail embankment. part of the Trail replacement; High R08 bridge priority replacement #10 Active Flood waters from the Brewster Install two Culvert installation Flood hazard reduction and FEMA funded None FEMA, LCPC, VANR, Town of At the junction of Route 108 Restoration River back up within Jeffersonville due culverts under currently underway; flood attenuation Cambridge, Village of Jeffersonville and Route 15 to encroachment of Route 15 Route 15 on High Priority R08 either side of Route 108 to carry 44.64689 -72.83292 floodwaters from the Brewster River to the Lamoille River #11 Active The southeastern bank is eroding due Regrade bank High Priority Flood and sediment Moderate to high None VANR, LCPC, Town of Cambridge, Begins approximately 630 feet Restoration to lack of buffer. Bank erosion is and restore attenuation, water quality costs of floodplain Village of Jeffersonville downstream of Route 108 jeopardizing trail location. floodplain to improvement; recreation restoration including bridge and continues for about reduce erosion, asset protection design, materials and 44.64766 -72.82979 500 feet along the southeastern improve water implementation bank quality, and R08 protect recreation trail. #12 Active Riparian buffer is narrow, especially Streamside High Priority Reduce erosion, improve Cost of plantings: Crop and/or hayfields to forested buffer VANR, LCPC, landowner;, USFWS, Begins at Route 15 and Restoration on the left bank, and dominated by plantings or habitat and reduce water $4,500/acre LCCD continues to the “Wrong Way” herbaceous vegetation. Erosion is buffer temperature 44.64902 -72.82711 bridge in Cambridge Village. extensive on both sides. regeneration R08 #13 Passive Historic channel incision has led to Protect River Moderate Priority Flood and sediment Cost of corridor VANR, LCPC, landowner, VLT Begins at Route 15 bridge and restoration extreme channel widening, and major Corridor attenuation easement of 228.5 continues to the “Wrong Way” channel aggradation and planform through acres ≈ $395,000; bridge in Cambridge Village. change. corridor portions of southern 44.64892 -72.82759 R08 easement corridor already conserved by VLT. Possible expansion of easement. 3

3 Cost of easement from Vermont Agency of Natural Resources, based on average cost of easements of $1,727 per acre. Range of cost of easements is from $0 (donation) to $4,676 per acre.

River Corridor Plan Page 50 Lamoille River from Johnson to Cambridge Lamoille County Planning Commission

Figure 20. Proposed restoration and protection projects for the Lamoille River reach R13

River Corridor Plan Page 51 Lamoille River from Johnson to Cambridge Lamoille County Planning Commission

Figure 21. Proposed restoration and protection projects for the Lamoille River reach R12

River Corridor Plan Page 52 Lamoille River from Johnson to Cambridge Lamoille County Planning Commission

Figure 22. Proposed restoration and protection projects for the Lamoille River reach R11

River Corridor Plan Page 53 Lamoille River from Johnson to Cambridge Lamoille County Planning Commission

Figure 23. Proposed restoration and protection projects for the Lamoille River reach R10

River Corridor Plan Page 54 Lamoille River from Johnson to Cambridge Lamoille County Planning Commission

Figure 24. Proposed restoration and protection projects for the Lamoille River reach R09

River Corridor Plan Page 55 Lamoille River from Johnson to Cambridge Lamoille County Planning Commission

Figure 25. Proposed restoration and protection projects for the Lamoille River reach R08

River Corridor Plan Page 56 Lamoille River from Johnson to Cambridge Lamoille County Planning Commission 7.5 Next Steps There are many opportunities to restore the Lamoille River to a stable condition. Types of reach level and site level projects that have been identified in this plan include river corridor protection, streamside plantings, and replacement of stream crossings. On the watershed level, the development and implementation of river corridors can help to avoid conflicts regarding land use and to save money spent on flood damage and river maintenance. The Towns of Johnson and Cambridge could pursue the opportunity to work with the LCPC and the Vermont River Management Program to ground truth, further refine and adopt river corridors for areas surrounding the Lamoille River where there is a history of repeated flooding and associated damages, so as to best protect public health and safety and prevent costly property damage. The following are recommendations for next steps:

1. Complete assessments for the remaining Lamoille River major tributaries. 2. Outreach to private landowners and the public about the plan and potential restoration and protection opportunities to be completed by the State and/or LCPC. 3. Town, State, and LCPC representatives meet to discuss the various restoration and protection opportunities and set priorities for action. 4. Meetings to be held with additional partners (Lamoille County Conservation District, Department of Agriculture, Natural Resources Conservation Service, Vermont Agency of Transportation, etc.) to discuss implementation of priority projects. 5. Summary and prioritization of potential projects. 6. Add priority projects to the Vermont DEC tactical basin planning Watershed Projects Database. 7. Implementation of priority projects with project partners and landowners.

For additional information about river corridors or project development, please contact the LCPC:

Lamoille County Planning Commission P.O. box 1637, 52 Portland Street Morrisville, VT 05661 (802) 888-4548 [email protected]

River Corridor Plan Page 57 Lamoille River from Johnson to Cambridge Lamoille County Planning Commission 8.0 Glossary of Terms

Adapted from: Restoration Terms, by Craig Fischenich, February, 2000, USAE Research and Development Center, Environmental Laboratory, 3909 Halls Ferry Rd., Vicksburg, MS 39180 And Vermont Stream Geomorphic Assessment Handbook, Appendix Q, 2004, VT Agency of Natural Resources, Waterbury, VT. http://www.vtwaterquality.org/rivers/docs/assessmenthandbooks/rv_apxqglossary.pdf

Adjustment process – type of change that is underway due to natural causes or human activity that has or will result in a change to the valley, floodplain, and/or channel condition (e.g., vertical, lateral, or channel plan form adjustment processes).

Aggradation - A progressive buildup or raising of the channel bed and floodplain due to sediment deposition. The geologic process by which streambeds are raised in elevation and floodplains are formed. Aggradation indicates that the stream discharge and/or bed load characteristics are changing. Opposite of degradation.

Alluvial fan – A fan-shaped accumulation of alluvium (alluvial soils) deposited at the mouth of a ravine or at the juncture of a tributary stream with the main stem where there is an abrupt change in slope.

Alluvial soils – Soil deposits from rivers.

Alluvium – A general term for detrital deposits made by streams on riverbeds, floodplains, and alluvial fans.

Avulsion – A change in channel course that occurs when a stream suddenly breaks through its banks, typically bisecting an overextended meander arc.

Bank Stability – The ability of a streambank to counteract erosion or gravity forces.

Bankfull channel depth - The maximum depth of a channel within a riffle segment when flowing at a bankfull discharge.

Bankfull channel width - The top surface width of a stream channel when flowing at a bankfull discharge.

Bankfull discharge - The stream discharge corresponding to the water stage that overtops the natural banks. This flow occurs, on average, about once every 1 to 2 years and given its frequency and magnitude is responsible for the shaping of most stream or river channels.

Bar – An accumulation of alluvium (usually gravel or sand) caused by a decrease in sediment transport capacity on the inside of meander bends or in the center of an over wide channel.

Berms – Mounds of dirt, earth, gravel or other fill built parallel to the stream banks designed to keep flood flows from entering the adjacent floodplain.

Cascade – River bed form where the channel is very steep with narrow confinement. There are often large boulders and bedrock with waterfalls.

Channelization – The process of changing (usually straightening) the natural path of a waterway.

Culvert – A buried pipe that allows flows to pass under a road.

Degradation – (1) A progressive lowering of the channel bed due to scour. Degradation is an indicator that the stream’s discharge and/or sediment load is changing. The opposite of aggradation. (2) A decrease in value for a designated use.

Delta bar – A deposit of sediment where a tributary enters the mainstem of a river.

Depositional features – Types of sediment deposition and storage areas in a channel (e.g. mid-channel bars, point bars, side bars, diagonal bars, delta bars, and islands).

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Drainage Basin – The total area of land from which water drains into a specific river.

Dredging – Removing material (usually sediments) from wetlands or waterways, usually to make them deeper or wider.

Erosion – Wearing away of rock or soil by the gradual detachment of soil or rock fragments by water, wind, ice, and other mechanical, chemical, or biological forces.

Floodplain – Land built of sediment that is regularly covered with water as a result of the flooding of a nearby stream.

Gaging Station – A particular site in a stream, lake, reservoir, etc., where hydrologic data are obtained.

Grade control - A fixed feature on the streambed that controls the bed elevation at that point, effectively fixing the bed elevation from potential incision; typically bedrock, dams or culverts.

Gradient – Vertical drop per unit of horizontal distance.

Habitat – The local environment in which organisms normally grow and live.

Headwater – Referring to the source of a stream or river.

Head cut – Sudden change in elevation or knickpoint at the leading edge of a gully

Incised River – A river that erodes its channel by the process of degradation to a lower base level than existed previously or is consistent with the current hydrology.

Islands – Mid-channel bars that are above the average water level and have established woody vegetation.

Lacustrine soils- Soil deposits from lakes.

Meander - The winding of a stream channel, usually in an erodible alluvial valley. A series of sine-generated curves characterized by curved flow and alternating banks and shoals.

Meander migration – The change of course or movement of a channel. The movement of a channel over time is natural in most alluvial systems. The rate of movement may be increased if the stream is out of balance with its watershed inputs.

Meander belt width – The horizontal distance between the opposite outside banks of fully developed meanders determined by extending two lines (one on each side of the channel) parallel to the valley from the lateral extent of each meander bend along both sides of the channel.

Meander wavelength - The lineal distance downvalley between two corresponding points of successive meanders of the same phase.

Meander wavelength ratio – The meander wavelength divided by the bankfull channel width.

Meander width ratio – The meander belt width divided by the bankfull channel width.

Mid-channel bar – Sediment deposits (bar) located in the channel away from the banks, generally found in areas where the channel runs straight. Mid-channel bars caused by recent channel instability are unvegetated.

Phase 2 Rapid Stream Assessment – A detailed protocol for gathering scientifically sound information about the stream channel and riparian corridor that can be used for watershed planning and detailed evaluations of aquatic habitat and erosion hazards.

Planform - The channel shape as if observed from the air. Changes in planform often involve shifts in large amount of sediment, bank erosion, or the migration of the channel.

River Corridor Plan Page 59 Lamoille River from Johnson to Cambridge Lamoille County Planning Commission Plane bed – Channel lacks discrete bed features (such as pools, riffles, and point bars) and may have long stretches of featureless bed.

Point bar –The convex side of a meander bend that is built up due to sediment deposition.

Pool -- A habitat feature (section of stream) that is characterized by deep, low-velocity water and a smooth surface.

Rapid Geomorphic Assessment – Physical geomorphic parameters are measured along each reach/segment to generate a existing stream type, reach condition, channel adjustment process and reach sensitivity. The assessment is used to understand the degree of departure of the channel from its reference condition.

Rapid Habitat Assessment – Physical habitat parameters are measured along each reach/segment assessed to generate a habitat condition rating. Habitat condition ratings can be used to identify high quality habitat and to “red-flag” areas of degraded habitat for more detailed evaluation.

Reach - Section of river with similar characteristics such as slope, confinement (valley width), and tributary influence.

Restoration – The return of an ecosystem to a close approximation of its condition prior to disturbance.

Riffle - A habitat feature (section of stream) that is characterized by shallow, fast-moving water broken by the presence of rocks and boulders.

Riffle-pool - Channel has undulating bed that defines a sequence of riffles, runs, pools, and point bars. Occurs in moderate to low gradient and moderately sinuous channels, generally in unconfined valleys with well-established floodplains.

Riparian Buffer – The width of naturally vegetated land adjacent to the stream between the top of the bank and the edge of other land uses. A buffer is largely undisturbed and consists of the trees, shrubs, groundcover plants, duff layer, and naturally uneven ground surface.

Riparian Corridor – Lands defined by the lateral extent of a stream’s meanders necessary to maintain a stable stream dimension, pattern, profile and sediment regime.

Segment – A relatively homogeneous section of stream contained within a reach that has the same reference stream characteristics but is distinct from other segments in the reach.

Sensitivity – The valley, floodplain and/or channel condition’s likelihood to change due to natural causes and/or anticipated human activity.

Side bar – Unvegetated sediment deposits located along the margins or the channel in locations other than the inside of channel meander bends.

Step-pool – Characterized by longitudinal steps formed by large particles (boulder/cobbles) organized into discrete channel-spanning accumulations that separate pools, which contain smaller sized materials. Often associated with steep channels in confined valleys.

Surficial sediment/geology – Sediment that lies on top of bedrock.

Tributary – A stream that flows into another stream, river, or lake.

Urban runoff – Storm water from city streets and gutters that usually carries a great deal of litter and organic and bacterial wastes into the receiving waters.

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9.0 REFERENCES

Bear Creek Environmental, LLC. 2009. Elmore Branch River Corridor Plan: Wolcott and Elmore, Vermont. Middlesex, Vermont. 55 pp. plus Appendices

Bear Creek Environmental, LLC. 2010a. Centerville Brook Corridor Plan: Hyde Park, Vermont. Middlesex, Vermont. 64 pp. plus Appendices.

Bear Creek Environmental, LLC. 2010b. Wild Branch Corridor Plan. Wolcott, Craftsbury and Eden, Vermont. Middlesex, Vermont. 94 pp. plus Appendices.

Doll, C. G. 1961. Centennial Geologic Map of Vermont. http://www.anr.state.vt.us/dec/geo/centmap.htm. Accessed June 2010.

Doolan, Barry L. 1996. The Geology of Vermont. Rocks and Minerals, Vol. 71, No.4. Washington, D.C.

Foreman, R.T.T. and L.E. Alexander. 1998. Roads and Their Ecological Effects: Annual. Review of Ecological Systematics. Vol. 29: 207-231.

Leopold, L.B. 1994. A View of the River. Cambridge, Massachusetts.

Montgomery, David and Buffington, John. 1997. Channel Reach Morphology in Mountain Basins. GSA Bulletin. Boulder, Colorado.

Rosgen, Dave. 1996. Applied River Morphology. Pagosa Springs, Colorado.

Ryan, J. 2001. Stream stability assessment of Lamoille County, Vermont. Washington, Vermont.

Schiff, R., J. S. Clark, and B. Cahoon, 2008. The Lamoille River and Black Creek Floodplain Restoration Project. In Proceedings of: AWRA 2008 Summer Specialty Conference: Riparian Ecosystems and Buffers, American Water Resources Association, Virginia Beach, VA.

United States Department of Agriculture. 1986. Urban Hydrology for Small Watersheds. Soil Conservation Service, Engineering Division, Technical Release 55. Washington, D.C.

USGS. 2007. United States Geologic Survey website. http://waterdata.usgs.gov/vt/nwis/rt

Vermont Agency of Natural Resources. 2005. Vermont Stream Geomorphic Assessment Phase 1 Handbook: Watershed Assessment Using Maps, Existing Data, and Windshield Surveys. Waterbury, Vermont.

Vermont Agency of Natural Resources. 2006. Fluvial Erosion Municipal Guide. Waterbury, Vermont.

Vermont Agency of Natural Resources. 2007a. Vermont Agency of Natural Resources River Corridor Planning Guide to Identify and Develop River Corridor Protection and Restoration Projects. (Partially Drafted July 2007). Vermont Agency of Natural Resources, Department of Environmental Conservation, River Management Program, Waterbury, Vermont.

River Corridor Plan Page 61 Lamoille River from Johnson to Cambridge Lamoille County Planning Commission Vermont Agency of Natural Resources. 2007b. Vermont Agency of Natural Resources Phase 2 Handbook, Rapid Stream Assessment Field Protocols. Vermont Agency of Natural Resources, Department of Environmental Conservation, River Management Program, Waterbury, Vermont.

Vermont Center for Geographic Information (VCGI). 2003. Vermont Hydrography Dataset. http://www.vcgi.org/dataware/.

Vermont Center for Geographic Information (VCGI). 2004. Geologic Soils_So. Soils – Natural Resources Conservation Service soil survey. http://www.vcgi.org/dataware/.

Wright, Stephen. 2003. Glacial Geology of the Burlington and Colchester 7.5’ Quads, VT. University of Vermont Burlington, Vermont. http://www.anr.state.vt.us/DEC/GEO/pdfdocs/GlacGeoBurlwright.pdf