Stream Crossings: Continuity at the Junction of Two Linear Ecosystems

Arnie Capute, Krystina Lincoln, Michaela Levine, Martin Strenk

Environmental Planning ­ ENVI 302 Fall 2015

Professor Sarah Gardner

TABLE OF CONTENTS

1. Introduction 1.1 Project Goals 1.2 Clients and Interested Parties 1.3 Project Background 1.4 Technical Considerations 1.5 Massachusetts State Standards 1.6 Economic Considerations of Culvert Replacement 1.7 Relevant Laws and Policies 1.8 Culvert Failures in Williamstown

2. Methods 2.1 Components of Surveying a Culvert

2.2 Survey Strategy 2.3 Evaluation Matrix 2.4 Challenges and Practicalities of Stream Crossing Replacements

3. Results

4. Recommendations

5. Acknowledgements

6. Sources

7. Appendix

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1. INTRODUCTION

1.1 PROJECT GOALS

Our initial goal for the project focused on surveying all 14 of the priority culverts in

Williamstown, MA, to contribute to the North Atlantic Aquatic Connectivity Collaborative

(NAACC) region­wide database. After collecting data on some of these unsurveyed culverts, we

decided to focus on a stream where improving one or a few culverts would make the largest

contribution to connectivity and restoring the health of a larger length of stream ecosystem, due

to the time constraints on our project. Ultimately, we recommended two specific culverts for

replacement based on an evaluation matrix that analyzed structural integrity, ecological integrity,

and availability of state infrastructure funds. However, due to the formal and time consuming

nature of such a proposal, we cannot formally recommend culverts for replacement to the state.

Nevertheless, our work will go to both the Berkshire Environmental Action Team (BEAT) and

the Williamstown Conservation Commission, who can act upon our recommendations on a

longer time scale.

1.2 CLIENT AND INTERESTED PARTIES

The clients for this project are Elia del Molino, a representative from Berkshire

Environmental Action Team who is also a local coordinator for the North Atlantic Aquatic

Connectivity Collaborative (NAACC), Williamstown officials, and Williamstown Conservation

Commission.

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Elia’s goals for the project centered on increasing the NAACC database of surveyed

stream crossings in Berkshire County. Our contribution to the region­wide dataset will help the

NAACC locate the most critical stream crossings. Ultimately, high priority culverts can be

replaced with better designs, increasing habitat connectivity, and maintaining structural integrity,

which will prevent culvert failures in the future. In the near future, Elia will be working with the

Berkshire Regional Planning Commission to prioritize culverts for replacement in each

Berkshire town, and our contributions to the dataset will increase the accuracy of these

recommendations.

Our team also worked with Williamstown officials to address infrastructure concerns in

Williamstown. By working with Jason Hoch (Town Manager), Andrew Groff (Town Planner),

Tim Kaiser (Director of Department of Public Works), and the Conservation Commission, our

team sought to balance the goals of all involved parties by crafting proposals for crossing

replacements.

1.3 PROJECT BACKGROUND

The North Atlantic Aquatic Connectivity group (NAACC) is a collaboration of a few

dedicated organizations whose goal is to become a cohesive and comprehensive group working

towards the betterment of infrastructure to support road­stream crossings. The current state of

stream­road crossings is far from ideal for both humans and organisms that live in these biomes.

After Hurricane Irene hit the Northeast region, MassDOT gave a grant to Adams and North

Adams amounting to over $200,000 to repair roads and culverts in the area (Jessen). Much of

this flooding was due to insufficient infrastructure at road­stream crossings that was destroyed,

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washed out, or simply could not handle such severe storm conditions and thereby caused even

more flooding. This is avoidable to a degree if proper crossings are put in place rather than

insufficient solutions that cannot handle high flow conditions and need to be replaced after major

storm events. The NAACC is addressing the dire need for an improvement of this infrastructure

not only for the implications an upgrade will have for people and their towns in terms of flood

resilience, but also to improve the aquatic connectivity in the region, better allowing aquatic

organisms to travel throughout the streams. The NAACC consists of a core team, which is

UMass, The Nature Conservancy,United States Fish and Wildlife Service, the Unites States

Forest Service, the Vermont Fish and Wildlife department, and a work group. The work group

consists of 13 states (CT, DE, MA, MD, ME, NH, NJ, NY, PA, RI, VA, VT, and WV), their

corresponding departments of transportation and natural resource agencies, the United States

Forest Service, the National Oceanic and Atmospheric Administration, the United States Fish

and Wildlife Service, and some various other conservation services. A large goal of the NAACC

is to survey the culverts and to prioritize culverts because of insufficient funding to get all

crossings up to the desired standard of the group. In order to prioritize, comprehensive surveys of

each culvert in a region must be taken, several scoring systems are then used to analyze these

surveys, the data must then be imputed to the online database, and then these results are used to

prioritize and suggest culverts to be repaired.

Part of the process in prioritizing the surveyed culverts is the ecological impact that the

connectivity, or lack thereof, is having on the various species in that area. Because connectivity

is far from the norm, Maine has 60% of the surveyed crossings listed as partial or complete

barriers, aquatic organisms are facing many challenges. Aquatic organisms must have access to

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the appropriate habitat, especially given that man made environmental impact can change stream

ecology quickly (Jackson 21). Aquatic organisms have to move through streams for various

different reasons­­some have daily movements searching for food while others have migratory

patterns specifically for breeding (Jackson 22). If stream connectivity is not maintained, an

essential area for many different species may become unfit for the purpose it used to serve.

When this happens, usually the simplest option is to go to a more fit part of the stream, but if a

large culvert that is perched is blocking the way the species cannot move on and will inevitably

die off. The dying off of individuals in a species is not of great concern, but it is important to

ensure the reproductive potential of the species as a whole by allowing access to breeding

grounds and inviting both immigration and emigration to ensure genetic diversity. Conservation

biologists have different estimates of minimum population size needed to maintain the viability

of a population for both the short and long term, but even if a population is small, and therefore

not considered viable, it can still survive if it is connected to a larger regional population

(Jackson 22). Lacking connectivity is obviously not a good situation for the fish to be in and this

fragmentation of habitat is often caused by insufficiently built infrastructure at road­stream

crossings.

In addition to fragmentation certain types of crossings can also cause habitat degradation

in several ways. Firstly, the culverts that are commonly used in crossings provide little to no

habitat in the culvert. The main reason for this is because substrate does not get into the pipe and

it just has a round metal bottom. This can be avoided if the culvert is partially placed in the

ground or substrate is added (Jackson 24). In addition to the culvert degrading the habitat by

replacing natural habitat, culvert installation and positioning can also alter the habitat negatively.

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Soil erosion and pollution will commonly runoff into streams during construction, after

installation from the disturbance, and from traffic along the road (Jackson 24). The positioning of

the culvert can also physically alter the biome. For example, water freefalling from the culvert

outlet could possibly cause a scour pool to form where one did not always exist. Aquatic biomes

are often very fragile so these pollutants and environmental alterations can cause extreme

hardships of the organisms living there. There are millions of road­stream crossing in the 13 state

area that the NAACC works in with an estimated 1.2 million solely in New York state, so it is

obvious that the area is in dire need of an infrastructure improvement for the sake of improving

these biomes. The organisms in this area include the; North Atlantic salmon, Eastern brook

trout, blacknose dace, salamanders, Blanding’s turtles, as well as terrestrial species that are

affected.

1.4 TECHNICAL CONSIDERATIONS:

Sizing and Durability

Properly constructed and designed culverts are essential for passing water during storm

events and reducing maintenance costs incurred through damage over time. Road crossing

structures need to accommodate both expected high flows and debris swept into the river during

storm events. Culvert designs typically use a minimum of a 20­year storm event for sizing and

some may be designed to manage the capacity of a 100­year storm based on local regulations and

sensitivities. Due to uncertainty in hydrological estimates and changing land use patterns, culvert

size and capacity should be conservative (BLM).

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Figure 1. Bureau of Land Management’s estimate for culvert size based on drainage area, slope, and vegetation conditions. Local conditions should be taken into consideration when sizing culverts.

The type of material used is generally based on cost, but metal and concrete are generally

more durable than plastic (BLM). The durability of materials is essential for decreasing the

average annual cost or lifecycle cost of the culverts. The culvert should also be designed so that

the flow of the stream is aligned with the structure and that the road is aligned perpendicular to

the stream (BLM). This increases the stability of the structures and its long­term viability.

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1.5 MASSACHUSETTS STATE STANDARDS

Culverts and bridges are typically designed with the sole aim of safely moving traffic and

facilitating the movement of water, sediment, and natural debris, which often unintentionally

damages the ecological health of the stream. In response to concerns over habitat fragmentation

due to hindered wildlife passage at stream crossings, the “Massachusetts River and Stream

Crossing Standards” were developed in 2004 to achieve fish and wildlife passage, in addition to

traditional goals of structural integrity, the movement of people, and hydraulic adequacy, at

crossings (MassDOT). The standards were developed using a “stream simulation” design

approach in which the structure is designed to mimic the natural channel throughout the crossing,

maintaining the connectivity of the stream and continuity of the ecosystem (MassDOT). These

standards, developed in partnership with the River and Stream Continuity Project, apply to all

new road crossings and repairs. If an existing crossing is assessed to support a reasonable degree

of wildlife passage, then options for improving that structure may include an in­kind replacement

(MassDOT). A stream crossing structure that meets the standards facilitates the movement of

fish and aquatic organisms, maintains the continuity of the aquatic and benthic elements of river

and stream ecosystems through the use of appropriate substrates and hydraulic characteristics,

and facilitates the movement of wildlife species that use riparian areas through the crossing.

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Figure 2. Diagram of a culvert meeting the general standards.

There are two sets of standards: general standards, which should be applied to all new

structures and repairs where possible, facilitate the movement of aquatic organisms and some

terrestrial wildlife, and the optimum standards, which should be applied to areas that play a

significant role in habitat connectivity, provide for the passage of both aquatic and terrestrial

organisms. The general Standards require the implementation of either an open bottom structure

or a culvert embedded to a minimum of 2 feet to provide a natural stream substrate that matches

the undisturbed upstream and downstream substrates (RSCP). In addition, the structures should

avoid constriction causing increased velocity and depth. To avoid constriction and maintain the

stability of the culvert/bridge, the structure should be a minimum of 1.2 times the bankfull width

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in diameter. In floodplains, it may be necessary to widen the structure further to facilitate the

conveyance of water and maintain the structure’s stability. Banks should be present on both sides

of stream within the structure, matching the natural channel conditions, to further support its

structural integrity and provide space for the passage of terrestrial wildlife. Finally, the general

standards require that the structure have an openness ratio (measured as the cross sectional area

divided by the structure length) of at least 0.82 feet to allow the passage of small terrestrial

animals (RSCP). In comparison, the U.S. Army Corps of Engineers requires an openness ratio of

0.25 (U.S. Army Corps of Engineers). The optimum standards provide for fish passage, stream

continuity, and passage of all terrestrial wildlife. While many of the standards are the same, the

optimum standards prohibit the use of culverts and require the use of a bridge to minimize

impacts on the stream channel and provide more space for the passage of wildlife. The optimum

standards require that the structure have a minimum height of 8 feet and an openness of 1.64 feet

(RSCP). Optimum standards are applied to crossings in stream corridors linking areas of

significant habitat, including river and stream segments identified by the Natural Heritage and

Endangered Species Program (NHESP) through the “BioMap2” project.

1.6 ECONOMIC CONSIDERATIONS OF CULVERT REPLACEMENT

The Chapter 90 Funding Program

Massachusetts Department of Transportation Chapter 90 Program is one potential source

for completing culvert renovation/replacement projects. This program provides 100%

reimbursement to projects that involve the “maintenance, repair, improvement and construction

of town ways and bridges, which qualify under the State Aid Highway Guidelines” (MassDot).

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The main requirement for a culvert project to be considered for Chapter 90 funding is that the

given project must be in conjunction with a roadway resurfacing project with a minimum of ¾

inches course and a continuous length of at least 500 feet (MassDot). This essentially means that

a culvert renovation/replacement would not qualify for Chapter 90 funding on its own, but

instead, must be tied in with a pre­existing need for substantial repaving in the given area.

In our discussions with Jason Hoch, the town manager, he suggested that Chapter 90 is

often the best bet for receiving adequate funding, so in the second phase of our survey practices,

we increased our focus on the condition of the roadway. Just as we will not be submitting any

formal recommendations for replacement, we will also not be involved in the actual application

process for Chapter 90 funding as it is a lengthy process which extends beyond our time frame,

and since it is a reimbursement program, the actual application for funding does not take place

until after construction begins. Our role was merely to identify culverts and roadway water

passages that are priorities based on structural integrity and ecological benefit, and then make a

conclusion as to whether the roadway itself needs repair and could apply for Chapter 90.

Cost Benefit Analysis

When installing a culvert there are funding and other considerations that are important to

analyze thoroughly. Often the initial costs are given too much weight in the decision of what

type of culvert to install and the operation, maintenance,

and replacement (OM&R) costs are not given enough thought

(Economics of Culvert Replacement). The process that should

be used to determine the best type of culvert to construct is the life cycle cost analysis. This

method takes all costs throughout the life of a culvert into account, including OM&R, time, and

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financial assistance available (Brovia). Cost and funding are often the leading concerns, so

cheap, unsatisfactory, and high maintenance culverts are often installed, which often end up

being more costly over its lifespan than the proper culvert. There are funding sources that will

subsidize culverts to improve wildlife connectivity, for example, the Wildlife Incentive Program,

will cover 90% of installation costs of a culvert if it meets their environmental standards

(Economics of Culvert Replacement). This subsidy not only incentivizes better stream

continuity, but as a result, culverts are built bigger and, therefore, less maintenance is needed

over time, lowering total life cycle costs.

Figure 3: Life Cycle cost analysis of unsatisfactory/undersized culverts in red against proper culvert costs, in green, over the span of 25 years. It is important to note that there is no subsidy for the proper culvert taken into account and the expected life for the proper culvert far exceeds the 25 year timespan that an unsatisfactory culvert is expected to last (USDA)

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According to a study done by the Transportation Research Board, there are fairly accurate

expected lifespans for culverts of different materials. They found that concrete culverts are the

longest lasting with lifespans of 70­100 years, where plastic and metal culverts general have

expected lifespans of 50 years when properly installed with adequate spacing (Brovia). This

study then looked at several different culvert installations and found that in the 7 case studies

they analyzed, all culverts that failed had exceeded their expected lifespans. These failures

caused hours of delay in detours for many travelers as they were on busy roads, $265,000 to $8

million in replacement costs, and none of these culverts even had planned maintenance in the

near future (Brovia). Because emergency replacement is more costly than planned maintenance

and repair, there are advantages to maintaining culverts instead of only replacing them when they

fail. Because of this, the Transportation Research Board looked into a culvert installation firm

that had a maintenance program and found that they have yet to have a culvert failure. Their

program, simply enough, has employees conduct surveys of their culverts every 2 years and then

when a deficiency is found it is either fixed or replaced (Brovia). Because of this program, the

company has a much lower lifetime cost for each culvert because there are no emergency

replacements. All of these analysis unfortunately do not take the environment into account, but

there is a correlation between strong properly built culverts and stream connectivity, and there

are incentive programs to push for more stream connectivity. The end results indicate that strong

culverts and high environmental quality come hand in hand so the incentives are aligned in this

case.

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1.7 RELEVANT LAWS AND POLICIES

State Level

Extensions of waterways that supply drinking water, habitat, and flood control, culverts

are subject to the statewide “Wetlands Protection Act” and “Water Quality Certification for

Discharge of Dredged or Fill Material, Dredging and Dredged Material Disposal in Waters of the

United States Within the Commonwealth” regulations (MassDOT). The Massachusetts 401

Water Quality Regulations outline standards requiring permits for any dredging or filling

activity, which would pertain to culvert construction and any armoring measures at outlets. Also,

the regulations call for structural techniques that prevent storm water from overriding the natural

channel and introducing pollutants. Pipes and culverts must be designed to manage storm water

as such (Massachusetts 401 Water Quality Regulations). Additionally, these regulations outline

when a permit or application is required for any roadway projects.

The Wetlands Protection Act must be considered when evaluating culverts and again

during the replacement process. Poorly designed culverts that severely restrict flow may lead a

wetland to develop in the area around the stream. While this wetland was not originally a natural

feature, any alteration to it would require review under the Wetlands Protection Act (MassDOT).

The Massachusetts DEP equally considers benefits of full river restoration against potential harm

to the wetland resource, so culvert replacement proposals should not be deterred by the

MassDEP review.

The Massachusetts Endangered Species Act (MESA) prohibits the taking of rare species

and protects their habitats. “Take” is defined in reference to animals as “harass, harm, pursue,

hunt, shoot, wound, kill, trap, capture, collect, process, disrupt the nesting, breeding, feeding or

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migratory activity” (Energy and Environmental Affairs). If a project is located within a Priority

Habitat of Rare Species, as defined by the Natural Heritage & Endangered Species Program, then

the proponents of the project must file with the NHESP and undergo MESA Project Review. For

a project to receive a Conservation and Management Permit during a MESA Project Review, the

applicant must demonstrate the project will impact an insignificant portion of the local

population of the affected species and design and implement a conservation plan that provides a

long­term net benefit for the affected species (Energy and Environmental Affairs). Thus, if a new

culvert project is proposed in a Priority Habitat of Rare Species, then the culvert must be

designed to have minimal to no impact on the connectivity of the ecosystem.

Federal Level

The New England District of the U.S. Army Corps of Engineers (USACE) issued the

Massachusetts General Permit (MGP) in 2010 to expedite the review of activities with minimal

impacts on the aquatic environment. The MGP includes the “General Condition 21. Stream

Crossings and Work,” which requires that all crossings be designed to withstand high flows and

not disrupt life­cycle movements of those species native to the stream. The Condition requires

that new stream crossings and replacements meet the “Massachusetts River and Stream Crossing

Standards” to qualify for Category 1, no application required, activities. Replacement crossings

in high­quality stream segments (including, those designated by NHESP) are not eligible for

Category 1 approval. For projects that do not meet Category 1 approval, the least ecologically

damaging designs are required (MassDOT). The Corps must issue an individual permit for

Category 2 projects, which do not meeting the conditions. The USACE also issued the

Massachusetts Department of Transportation a Comprehensive Permit for Bridges covering

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repair, replacement, and reconstruction unless the project spans more than 5,000 square feet of

vegetated wetlands or waters, the project affects a federally listed endangered species, the bridge

intersects the 10­year flood elevation, the bridge constricts flow, there is a dam or other

obstructing element within the footprint of the project,the bridge does not span 1.2 times the

bankfull width, and the bridge does not meet the “Stream Crossing Standards” (MassDOT).

1.8 CULVERT FAILURES IN WILLIAMSTOWN

Culvert failure is not an unfamiliar problem in Williamstown. Many of the culverts are

undersized and therefore prone to flooding during extreme storm events. After a torrential rain

event in May, 2013, the current Williamstown Town Manager reported road closures and

hundreds of thousands of dollars in damage due to failed culverts ("Torrential Rain Closes,

Damages Williamstown Roads"). Water Street, Green River Road, and Routes 2 and 7 were all

underwater at points of the storm, which indicated undersized culverts that should have

accommodated the high water flow and kept the water within the stream banks. Additionally,

undersized culverts are prone to blockage during these storm events when debris is mobilized

and transported.

During Tropical Storm Irene, a culvert failure along Route 2 near the Spruces mobile

home park contributed to “the worst flood in recent memory” (Dravis, 2014). This culvert

failure, in conjunction with flooding from the Hoosic River, led to the complete destruction of

the mobile home, which culminated in its condemnation (Dravis, 2014). Ultimately,

Massachusetts Department of Transportation undertook the culvert replacement project, which

totaled $192,000 (Stafford). The replacement project installed three, three foot pipes in the area

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which previously only had one three foot pipe. Additionally, MassDOT installed a swale to ease

the pressure of high flows (Dravis, 2013). Further conversation with Jason or Williamstown

Conservation Commission members will inform our team about the process of culvert

replacement in times of crisis.

2. METHODS

2.1 COMPONENTS OF SURVEYING A CULVERT

We have assessed road­stream crossings throughout the Williamstown area through the

completion of a previously established NAACC Stream Crossing Survey Data Form at each

passage site evaluated (see appendix). After completing field and online training, we conducted

our own surveys of stream crossings in teams of 2 people.

Stream crossing structures can be classified into seven different types: round culvert,

pipe arch/elliptical culvert, open bottom arch culvert, box culvert, bridge with side slopes, box

bridge with abutments, and a bridge with side slopes. Crossing structures are commonly built

from metal, concrete, plastic, wood, rock, or fiberglass. After identifying the culvert type, the

width, height, length, water width, and water depth are measured at the inlet, where water enters

the structure, and outlet, where water leaves the structure (see Figure 4).

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Figure 4: Types of stream crossing standards showing where measurements should be taken (“NAACC Stream Crossing Survey Data Form”).

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At the inlet, the surveyor accesses the inlet type and inlet grade. An inlet can have

wingwalls, angled walls that funnel water flow into the structure, and/or a headwall, a vertical

wall where the water enters the structure. If the structure is a pipe culvert, the inlet can be

projecting if the inlet is not flush with the road embankment. Structures that are mitered to the

slope are flush to the slope of the road embankment. The inlet grade refers to the elevation of the

stream bottom as it enters the structure. The structure is at grade when the stream bottom is at the

same elevation as the stream bottom upstream of the structure; the structure has an inlet drop

when the water falls into the structure due to a decrease in elevation; and the structure is perched

when the structure bottom is above the water surface at the inlet.

The surveyor also accesses the outlet grade as either at stream grade, when there is no

significant elevation change between the structure and the channel downstream, a free fall, when

the outlet structure is raised above the stream bottom so that water drops vertically when exiting

the structure, a cascade, when flows steeply downward over rock or other hard material at the

outlet, or a freefall into a cascade. The surveyor also notes whether the structure is clogged or

has armoring. The presence and size of a scour pool, which forms from high flows exiting the

crossing causing the width, length and depth in the area directly outside the outlet is at least

twice that of the natural stream.

The NAACC survey also examines the interior conditions of the crossing structure. The

surveyor looks for any physical internal structures such as baffles, weirs, or fencing, and any

physical barriers such as accumulated debris, deformation of the structure, internal free falls, or

dry areas. The survey also evaluates the structure for the presence of a substrate, the substrate

coverage in the structure, the substrate type, and the appropriateness of the substrate in regards

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the upstream and downstream substrate quality. In addition, the surveyor notes the presence or

absence of dry passage in the structure.

Additionally, the survey examines flow conditions. The crossing is aligned when the flow

of the stream enters the crossing at an angle less than 45 degrees, and the crossing is skewed

when the flow enters an angle greater than 45 degrees. The surveyor also notes whether the

velocity of the water in the crossing structure matches the upstream and downstream velocities.

The flow is evaluated for constriction based on the width of the crossing in relation to the

bankfull width of the upstream channel. All surveys should be conducted at typical low flow

conditions for safety purposes.

Finally, the survey provides a space for identifying the crossing with the road, GPS

coordinates, crossing code, and location description. The survey includes pictures of the inlet,

outlet, upstream, and downstream reaches. The survey form also provides space for additional

comments about the structure and its location.

2.2 SURVEY STRATEGY

After completing training, the research team targeted unsurveyed or unmarked culverts

for evaluation. These 8 surveys were added to the NAACC database of stream crossings. Once

most crossings in Williamstown were surveyed, we decided to evaluate previously surveyed

culverts to propose a multi­culvert repair that would reconnect significant habitat. Several

culverts along Sweet Brook had already been surveyed and were calculated as a significant or

moderate barrier to aquatic passage. These crossings were surveyed again and examined for

additional criteria including road quality, development density, and structural integrity.

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Repairing culverts along one stream that can support a robust aquatic ecosystem is more

beneficial to wildlife than repairing a small culvert that contains a small mountainside drainage.

In addition, repairing a culvert upstream when a downstream culvert may be impassible does not

provide any ecological benefit. Thus, targeting one stream that has significant barriers to passage

allows the Town to cost effectively invest resources to reconnect the largest stretch of linear

ecosystem possible

2.3 EVALUATION MATRIX

To begin balancing the varying goals that may drive culvert replacement, we constructed

a rubric, or matrix, which would assign numerical values to relevant properties of a stream

crossing (Table 1). We identified three overarching goals that could drive a crossing

replacement: ecological connectivity, hazard mitigation, and funding availability. With these

comprehensive goals, the rubric can address the ecological impacts of a culvert replacement,

while considering the structural importance and funding feasibility of such a project.

Additionally, the rubric is structured so certain characteristics can be weighted more than others

depending on the interest of the client. Higher scores represent higher priority for replacement.

Our rubric included a “Value” column that can be adjusted to weight specific goals over

others. For our purposes, we attempted to normalize that Impacts Rating, the maximum of which

varied from trait to trait. In our iteration of the rubric, the maximum impact rating for each

section was normalized to 1 with the value multiplier.

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Table 1: Stream Crossing Evaluation Rubric with Scoring Ranges

Goal 1: Ecological Connectivity Value Impact Rating

IEI Score 0.023440 0­42.66281 (Berkshires)

Barrier to Passage Rating .2 0­5

NHESP Status .5 0­1

BioMap 2.0 Status (Aquatic Core layer) .5 0­1

Linear Ecosystem .33 0­3

Goal 2: Hazard Mitigation Value Impact Rating

Flood Plain Status 0­1

Structural Integrity 0­3

Development Density 0­3

Goal 3: Funding Availability Value Impact Rating

Potential Chapter 90 Status 0­1

Structural Integrity 0­3

Traffic 0­1

Development Density 0­3

Ecological Connectivity

The first goal ­ ecological connectivity ­ addresses ecosystem health and environmental

traits that may increase the importance of a crossing replacement. The IEI (Index of Ecological

Integrity) score was created by the Critical Linkages project to evaluate crossings for predicted

impact on ecological integrity, if they had were updated to have sufficient passage. A high IEI

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score indicates the greatest improvement to ecological integrity (McGarigal et al., 2012). The

raw IEI score was placed into the evaluation matrix (see Figure 5).

Figure 5. Williamstown culverts with their IEI delta scores. Top 1% in the Berkshires is a score greater than 42.662810, top 5% is a score greater than 24.537955, top 10% is a score greater than 16.59998, top 20% is a score greater than 7.791426 (data from "Conservation Assessment and Prioritization System.").

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The Barrier to Passage score is calculated by an algorithm in the NAACC database

("North Atlantic Aquatic Connectivity Collaborative"), effectively synthesizing and interpreting

field data. NAACC data is shown in Figure 6. The rubric assigns values as follows:

Table 2: Barrier to Passage Values

Barrier Level Value

Severe 5

Significant 4

Moderate 3

Minor 2

Insignificant 1

Full Passage 0

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Figure 6. NAACC calculated Barriers to Passage in Williamstown (data from "North Atlantic Aquatic Connectivity Collaborative”).

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A culvert is given an NHESP score of (1) if it lies within an area (see Figure 7) classified

as “Priority Habitats of Rare Species.” If the crossing does not lie within this area, is is given a

score of (0). The NHESP Priority Habitats of Rare Species data layer is available from MassGIS

("MassGIS Data ­ NHESP Priority Habitats of Rare Species").

Figure 7. NHESP designated Priority Habitats in Williamstown, the known geographical extent of all state listed rare species (data from "MassGIS Datalayers").

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Each culvert was scored in the same fashion by referencing the BioMap 2.0 Aquatic Core

Habitat data layer (Figure 8). Also developed by the NHESP, “Aquatic Cores are designed to

protect 10 MESA­listed fish, 17 non­listed fish, as well as 145 MESA­listed species with all or a

portion of their life cycle in aquatic habitats” ("MassGIS Datalayers").

Figure 8. BioMap2 aquatic core habitat as designated by the NHESP for Williamstown are shown in green (data from "MassGIS Data ­ NHESP Priority Habitats of Rare Species").

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The linear ecosystem score reflects the size of the stream, representing the capacity for

the flow to support fish and other wildlife. Streams are scored as follows: large river (3), main

river (2), small creek or brook (1), unnamed (0). These values reflect the amount of potential

habitat upstream of the crossing.

Hazard Mitigation

The second goal­ hazard mitigation­ is designed to measure the impact high flow or flood

conditions would have on the surrounding area. The three categories observed were; floodplain

status, structural integrity, and development density. These three factors took into account the

damage that could occur with a culver failure. Floodplain status prioritizes the frequency of

floods in the area rather than the severity of the flood. This measure was scored as a binary ­ a

crossing was given a 1 if within the FEMA Designated 100 Year Flood Zone, or a 0 if not

(Figure 9). This part of the rubric assigns values as follows:

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Figure 9. FEMA designated flood zones. Zones A and AE are areas within the determine 100 year floodplain. Zone AH experience ponding during 100 year flood events. Zones V and Ve experience velocity hazards during the 100 year flood. Zone D is an area of undetermined hazard, and x500 is an area that floods during the 500 year flood (data from "MassGIS Datalayers").

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In the field, each crossing was judged based on structural integrity, considering the

urgency of replacement. Values were assigned according to Table 3.

Table 3: Structural Integrity Values

Barrier Level Value

Desperate 3

Poor 2

OK 1

New 0

In the field, crossing environment was evaluated as presented in Table 4. This was scored

considering the amount of structures in the immediate area, and served as a proxy for potential

damage in a high flood event.

Table 4: Development Density Values

Barrier Level Value

High (6+) 3

Medium (4­5) 2

Low (1­2) 1

No Development 0

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Funding Availability

The last goal in the rubric ­ funding availability­ uses the same metrics for development

density and structural integrity as presented above, but adds traffic frequency and chapter 90

funding availability. Both of these are measured on a binary scale, either yes or no. In discussion

with Andrew Groff, we determined if each crossing was on a town or state road, as only town

roads are Chapter 90 eligible. If a crossing was eligible for funding, we gave it a score of 1, if

not, a score of 0. Our rubric focuses on evaluating only town roads, and some sections of Route 7

and Route 43 are owned by the town rather than the state. We assumed that these roads would

have higher levels of traffic than other town roads, and scored such crossings with a 1.

Other Elements that may Impact Replacement

Our rubric does not take the cost of replacement into account. While this is a critical

factor when considering crossing replacement, cost of replacement can vary within hundreds of

thousands of dollars. Ultimately, this would require professional evaluation, but cost scales

roughly proportionally with size (Kaiser).

The rubric also did not consider the loss of fishing spots or swimming holes, which could

disappear with a properly sized culvert. While this may be important to the town for community

based reasons, it did not fit into our ecological and structural goals.

2.4 CHALLENGES AND PRACTICALITIES OF STREAM CROSSING REPLACEMENTS

While culverts should work towards stream habitat connectivity, there are several

practical considerations from the town’s perspective that should be taken into account in the

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planning of replacement projects. Crossing replacements can have both upstream and

downstream effects, even if the replacement mets stream crossing standards. Undersized culverts

can create upstream wetlands, and a replacement project could favor wildlife connectivity while

destroying these wetlands. Tim Kaiser, the Williamstown Director of Public Works, pointed out

that upstream undersized culverts may fail, causing local flooding in a sparely populated area

while preventing further flooding in a downstream area that would incur greater damage. This

was not considered in our rubric.

Additionally, the NAACC database may calculate a crossing as a barrier to passage

when, in fact, there are fish on both sides of the culvert. Culvert replacement may lead to the

destruction of tail water scour pools that act as fishing or swimming holes, which the public may

react negatively toward. Our matrix did not consider this aspect, in an attempt to be as qualitative

as possible.

3. RESULTS

The rubric was scored for each culvert our team surveyed, along with several culverts

along Sweet Brook (highlighted yellow) that were surveyed previously. Full results are seen in

Table 5. Higher scores indicate that replacing the culvert would have a greater benefit for each

subgoal. IEI scores were not available for culverts that were not in the NAACC database, so for

these crossings (highlighted orange) we estimated an IEI score by examining crossings upstream

and downstream. Barrier to passage scores were also unavailable for new and unsurveyed

culverts. We did not attempt to give theses culverts a barrier to passage score. This should be

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considered when interpreting our results and the matrix should be updated when the NAACC

completes the algorithm needed to calculate a barrier to passage score. The three crossings with

the highest score in each subtotal are highlighted.

Goal 1: ecological connectivity

value

xy4264083773224566

xy4263787373227511

xy4268231673201872

xy4268319473189697

xy4263757773276136

xy4264340473233440

xy4267721173259892

xy4267777673257123

xy4267920173251637

xy4268030173242330

xy4268349473246058

xy42650357323713

xy42644877323495

IEI score

0.02343

0.06075

0.00032

0.08180

0.03516

0.14112

0.00909

0.10006

0.29436

0.07949

0.06322

0.03516

0.03516

0.03516

passage 0.2 0.6 0.8 0.6 0.6

core habitat 0.5 0 0.5 0 0 0 0.5 0.5 0.5 0.5 0.5 0 0 0

NHESP 0.5 0 0.5 0 0 0 0.5 0 0 0 0 0 0 0.5 linear ecosystem

0.33

0.33 0.67

0.00

0.00

0.33 0.67

0.33

0.33 0.33 0.33

0.00

0.33

0.00

subtotal 0.39 1.67

0.08

0.04

0.47 1.68

1.53

1.93 1.51 1.50

0.04

0.37

0.54

Goal 2: hazard mitigation

flood plain 1 0 1 0 0 0 1 0 0 0 0 0 0 0 structural integrity 1 1 1 1 3 1 1 2 2 0 1 3 2 1 development density 1 1 1 1 1 1 0 1 1 1 0 1 0 0

subtotal 2 3 2 4 2 2 3 3 1 1 4 2 1 Goal 3: funding availability

chapter 90 1 1 0 1 0 1 0 1 1 1 1 1 0 0 structural integrity 1 1 1 1 3 1 1 2 2 0 1 3 2 1

traffic 1 0 1 0 0 1 1 0 0 0 0 0 1 1 development density 1 1 1 1 1 1 0 1 1 1 0 1 0 0

subtotal 3 3 3 4 4 2 4 4 2 2 5 3 2

Total 5.39 7.67

5.08

8.04

6.47 5.68

8.53

8.93 4.51 4.50

9.04

5.37

3.54

Table 5: Completed Evaluation matrix for each Crossing (designated by crossing code)

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4. RECOMMENDATIONS Based on the results of the evaluation matrix, we recommend the following three culverts

in Williamstown, MA for replacement. While they may not have the highest ecological scores,

they are the most practical for replacement based on funding availability and structural condition.

We recommend updating the crossing xy4267777673257123 (Figure 10) on Sweet Brook

and Woodcock Road to meet “Massachusetts River and Stream Crossing Standards.” The

crossing had an overall score of 8.93, the highest overall score on Sweet Brook. The crossing

also had the highest ecological score of all of the crossings we surveyed at 1.93, due to its high

passage score, significant barrier, its location in a Biomap2 core habitat, and significant IEI

score. The structure was rated as structurally poor and Chapter 90 funding is available.

Figure 10: Culvert xy4267777673257123 at Sweet Brook and Woodcock Road crossing.

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We also recommend updating the crossing xy4267721173259892 (Figure 11) to meet

the standards. The crossing is located downstream from the previously recommended culvert on

Sweet Brook and Woodcock Road. The overall score for this crossing is 8.53. This culvert is also

in the Aquatic Core habitat. The culvert is rated as structurally poor and Chapter 90 funding is

available. Both this culvert and the culvert upstream had significant free falls at the outlet. We

suggest repairing both of these culverts on Sweet Brook to connect a significant length of linear

ecosystem. Providing full passage at these two stream crossing will likely improve the overall

ecosystem health of Sweet Brook.

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Figure 11: Culvert xy4267721173259892 at the Woodcock Road Outlet.

The Williamstown DPW may also be interested in culvert xy4268349473246058 on

Oblong Road. The culvert had an overall rating of 9.04, the highest of all the crossings we

surveyed. While this crossing only had an ecological score of 0.04, the culvert has a hazard

mitigation score of 4 and funding availability score of 5, the highest score of all the culverts for

these subgoals. The culvert is in desperate need of repair and Chapter 90 funding available. The

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crossing’s outlet (see Figure 12) is very clogged and the road is collapsing. The inlet is also

severely constricted with signs of erosion. Despite its low ecological connectivity score, we

recommend repairing this culvert due to the severity of its structural instability.

Figure 12: Culvert xy4268349473246058 on Oblong Road outlet.

Recently the NAACC has updated its database and experts are still working to develop an

algorithm to calculate “Barrier to Passage” scores. When this information becomes available it

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should be integrated in the matrix for all crossings. For this project, the rubric only considered

this element for the Sweet Brook crossings, which had been surveyed previously.

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5. ACKNOWLEDGEMENTS

We would like to thank the following people for both their guidance and time

throughout this project:

Sarah Gardner

Elia del Molino

Carrie Banks

David Dethier

Andrew Groff

Jason Hoch

Tim Kaiser

ENVI 302 classmates

Williamstown Conservation Commission

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6. SOURCES

Brovia, Pam. “Good Culverts Gone Bad” Public Works Magazine. Available http://www.pwmag.com/bridges/good­culverts­gone­bad.aspx

“Chapter 90 Program” Massachusetts Department of Transportation Highway Division.

Accessed http://berkshirecountyhighway.org/chapter_90/default.html.

"Conservation Assessment and Prioritization System." Conservation Assessment and Prioritization System. N.p., n.d. Web. 03 Dec. 2015. http://www.umasscaps.org/data_maps/data.html

“Culvert Use, Installation, and Sizing” The Bureau of Land Management. Available

http://www.blm.gov/bmp/low%20volume%20engineering/J_Ch8_Culvert_Use_Installation_&_Sizing.pdf.

“Design of Bridges and Culverts for Wildlife Passage at Freshwater Streams” Massachusetts

Department of Transportation Highway Division. December 2010. Dravis, Stephen. "Route 2 Drainage Project Won't Change Flooding at Spruces."

IBerkshires.com. 14 Aug. 2014. Web. 26 Oct. 2015. Dravis, Stephen. "Williamstown, MassDOT Talk Flooding & Road Work."

IBerkshires.com. 27 Sept. 2013. Web. 26 Oct. 2015. Hoch, Jason. Personal interview. 27 Oct. 2015. Jackson, Scott D. "Ecological Considerations in the Design of River and Stream Crossings."

UMass Amherst. 2003. Web. 26 Oct. 2015. Jessen, Klark. “MassDOT Grants: Tropical Storm Irene Repairs.” MassDOT.gov. 22 Dec. 2011.

Web. 26 Oct. 2015. “Massachusetts River and Stream Crossing Standards” River and Stream Continuity

Partnership (University of Massachusetts Amherst, The Nature Conservancy, Massachusetts Division of Ecological Restoration­Riverways Program American Rivers), March 2006. www.streamcontinuty.org.

"MassGIS Datalayers." Administration and Finance. Web. 03 Dec. 2015.

http://www.mass.gov/anf/research­and­tech/it­serv­and­support/application­ serv/office­of­geographic­information­massgis/datalayers/layerlist.html

"MassGIS Data ­ NHESP Priority Habitats of Rare Species." Administration and Finance.

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Commonwealth of Massachusetts, Oct. 2008. Web. 03 Dec. 2015. http://www.mass.gov/anf/research­and­tech/it­serv­and­support/application­serv/office­of­geographic­information­massgis/datalayers/prihab.html

“NAACC Stream Crossing Survey Data Form.” NAACC. 24 May 2015. "North Atlantic Aquatic Connectivity Collaborative." NAACC. Web. 3 Dec. 2015.

www.streamcontinuty.org. “Openness Ratio Spreadsheet.” New England District, U.S. Army Corps of Engineers.

http://www.nae.usace.army.mil/Portals/74/docs/regulatory/ StreamRiverContinuity/OpennessRatioSpreadsheet.pdf.

Stafford, Scott. "Route 2 Culvert Project in Williamstown Nears Completion." Berkshire Eagle

Online. 25 Aug. 2014. Web. 26 Oct. 2015. “Regulatory Review” Executive Office of Energy and Environmental Affairs. Natural

Heritage and Endangered Species Program. http://www.mass.gov/eea/agencies/dfg/dfw/natural­heritage/regulatory­review/.

Kaiser, Tim. Personal interview. 17 Nov. 2015. “The Economics of Culvert Replacement, Fish Passage in Eastern Maine” National

Resource Conservation Service. http://www.nrcs.usda.gov/wps/PA_NRCSConsumption/download?cid=nrcs143_009452&ext=pdf

"Torrential Rain Closes, Damages Williamstown Roads." NorthAdams.com. 30 May 2013. Web.

26 Oct. 2015. McGarigal K, BW Compton, SD Jackson, E Plunkett, and E Ene.“Critical

Linkages Phase 1: Assessing Connectivity Restoration Potential for Culvert Replacement, Dam Removal and Construction of Wildlife Passage Structures in Massachusetts”. 13 July 2012. Report to Massachusetts Department of Transportation and The Nature Conservancy. 28 pgs.

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APPENDIX

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