New Book Aims to Protect and Restore Fish Migrations

Rivers are a critical natural resource and an essential element for the health and survival of billions of people and countless species. Flourishing populations of migratory fish are an important indicator of a healthy, coastally connected river and a robust aquatic ecosystem as a whole. Migratory fish help to maintain a balanced food web, support productive river systems, and provide income for people around the world.

Yet many migratory fish species are severely threatened primarily due to man-made obstacles like dams and weirs, which disrupt the natural flow of rivers and prevent fish migration. When fish can’t reach their habitat, they can’t reproduce and maintain their populations.

Photo Credit: “From Sea to Source 2.0”

A new book, titled From Sea to Source 2.0, explores the challenges that lie behind restoration of fish migration in rivers around the world and provides a practical guide to promoting the protection and restoration of fish migration. The book is a unique collaboration of over 100 international fisheries professionals and supported by river managers, governments, research institutes and NGOs including World Wildlife Fund and The Nature Conservancy. Geared toward practitioners, but also a wonderful resource for the general public, the book is comprised of inspiring stories from nearly every continent on the planet. Click here to download it for free.

“Ultimately our ambition is to contribute in a positive way to making a better world and a positive difference for migratory fish, nature and humans on local and global levels by inspiring new initiatives for and with people all around the world,” as stated on www.fromseatosource.com. “Whether the challenge is simply to increase access to spawning habitats through connectivity improvements for salmon, or to maintain the livelihoods for hundreds of millions of people dependent upon fish and fisheries in the great rivers of Asia, Africa and South America, we hoped our book would help to achieve these goals.”

Princeton Hydro’s Dam Removal Expert Laura Wildman, P.E. and Fluvial Geomorphologist Paul Woodworth are proud contributors to the book, helping to write the dam removal chapter, creating a dam removal flow chart for the book, and providing multiple photos utilized in the book. Princeton Hydro is also listed as a contributing sponsor.

“We’re so proud to be part of this incredible project with so many partners globally,” said Wildman. “We envision that this book will provide a valuable resource and inspiration for those in countries and regions where the importance of restoring riverine connectivity is newly gaining momentum. We hope it will help emphasize the importance of finding balanced and environmentally informed solutions when proposing additional utilization of public trust resources such as rivers.”

Approximately 40% of all fish species in the world reside in freshwater ecosystems, contributing economic and ecological benefits and value. It’s critical that we support efforts that aim to protect migratory fish species, reconnect rivers, sustain fish passage, and preserve free-flowing rivers through removing unnecessary dams, reconnecting floodplains, managing our water use, and managing hydropower for sustainable rivers.

Education and awareness building are key first steps in protecting rivers. From Sea to Source 2.0 seeks to inform, educate and inspire those who want to know more about how to meet the challenges of restoring fish migration in rivers around the world.  The book is regarded as a crucial resource in the ongoing fight to protect and preserve the enormous value of our waterways.

Get your free copy here.

Princeton Hydro has designed, permitted, and overseen the reconstruction, repair, and removal of a dozens of small and large dams in the Northeast. To learn more about our fish passage and dam removal engineering services, visit: bit.ly/DamBarrier.

Understanding and Addressing Invasive Species

Photo from: New York State Department of Environmental Conservation, water chestnut bed at Beacon

Spring is officially here! Tulips will soon be emerging from the ground, buds blossoming on trees and, unfortunately, invasive plant species will begin their annual growing cycle. No type of habitat or region of the globe is immune to the threat of invasive species (“invasives”). Invasives create major impacts on ecosystems throughout the world, and freshwater ecosystems and estuaries are especially vulnerable because the establishment of such species in these habitats is difficult to contain and reverse.

This blog provides an introduction to invasive aquatic species, including information that will help you prevent the spread of invasives in the waterways of your community.

Defining Invasive Species

Invasive species can be defined as non-native occurring in an ecosystem that is outside its actual natural or native distributional range. Although the colonization of an ecosystem by non-native species can occur naturally, it is more often a function of human intervention, both deliberate and accidental. For aquatic ecosystems some species have become established as a result of the aquarium trade, fish culture practices and/or transport of plants and animals in the bilge and ballast water of trans-oceanic shipping vessels.

One of the primary reasons invasives are able to thrive, spread rapidly, and outcompete native species is that the environmental checks and predators that control these species in their natural settings are lacking in the ecosystems and habitat in which they become introduced. The subsequent damages they cause occur on many ecological levels including competition for food or habitat (feeding, refuge and/or spawning), direct predation and consumption of native species, introduction of disease or parasites, and other forms of disruption that lead to the replacement of the native species with the invasive species. As a result, invasives very often cause serious harm to the environment, the economy, and even human health. A prominent example is the Emerald Ash Borer, a non-native, invasive beetle that is responsible for the widespread death of ash trees.

As noted above, there are a large number of aquatic invasive species. Some of the more commonly occurring non-native aquatic plant species that impact East Coast lakes, ponds and reservoirs include:

Understanding How Invasives Spread

Either intentionally or unintentionally, people have helped spread invasives around the globe. This is not a recent phenomenon but rather something that has been occurring for centuries. “Intentional introductions,” the deliberate transfer of nuisance species into a new environment, can involve a person pouring their home aquarium into a lake or deliberate actions intended to improve the conditions for various human activities, for example, in agriculture, or to achieve aesthetics not naturally available.

Photo by: Tom Britt/CC Flickr, zebra Mussels adhered to a boat propeller“Unintentional introductions” involve the accidental transfer of invasives, which can happen in many ways, including aquatic species attached to the hull of boats or contained in bilge and ballast water. A high-profile example is the introduction of zebra mussels to North America. Native to Central Asia and parts of Europe, zebra mussels accidentally arrived in the Great Lakes and Hudson River via cargo ships traveling between the regions. The occurrence, density, and distribution of Zebra mussels occurred at an alarming rate, with the species spreading to 20 states in the United States and to Ontario and Quebec in Canada. Due to their reproductive fecundity and filter-feeding ability, they are considered the most devastating aquatic invasive species to invade North American fresh waters. They alter and diminish the plankton communities of the lakes that they colonize leading to a number of cascading trophic impacts that have especially negative consequences on fisheries. Zebra mussel infestations have also been linked to increased cyanobacteria (bluegreen algae) blooms and the occurrence of harmful algae blooms (HABs) that impact drinking water quality, recreational use, and the health of humans, pets, and livestock.

Additionally, higher than average temperatures and changes in rain and snow patterns caused by climate change further enable some invasive plant species to move into new areas. This is exemplified by the increased northly spread of hydrilla (Hydrilla verticillate), a tropical invasive plant species that has migrated since its introduction in Florida in the 1950s to lakes, rivers, and reservoirs throughout the U.S.

Regardless of how any of these invasive species first became established, the thousands of terrestrial and aquatic invasive species introduced into the U.S. have caused major ecological, recreational and economic impacts.

Measuring the Impacts of Invasives

After habitat loss, invasive, non-native species are the second largest threat to biodiversity. According to The Nature Conservancy, “Invasive species have contributed directly to the decline of 42% of the threatened and endangered species in the United States. The annual cost to the nation’s economy is estimated at $120 billion a year, with over 100 million acres (an area roughly the size of California) suffering from invasive plant infestations. Invasive species are a global problem — with the annual cost of impacts and control efforts equaling 5% of the world’s economy.”

Of the $120 billion, about $100 million per year is spent on aquatic invasive plant control to address such deleterious issues as:

  • Human health (West Nile Virus, Zika Virus)
  • Water quality impacts (Canada geese)
  • Potable water supplies (Zebra mussel)
  • Commercial fisheries (Snake head, lamprey, Eurasian ruffe, round goby)
  • Recreational activities (Eurasian watermilfoil, water chestnut, hydrilla)
  • Biodiversity (Purple loosestrife, common reed, Japanese knotweed)

Invasive species can change the food web in an ecosystem by destroying or replacing native food sources. As the National Wildlife Federation explains, “The invasive species may provide little to no food value for native wildlife. Invasive species can also alter the abundance or diversity of species that are important habitat for native wildlife. Additionally, some invasive species are capable of changing the conditions in an ecosystem, such as changing soil chemistry…”

Addressing Invasives

Our native biodiversity is an irreplaceable and valuable treasure. Through a combination of prevention, early detection, eradication, restoration, research and outreach, we can help protect our native heritage from damage by invasive species.

What Can We Do?

  • Reduce the spread
  • Routinely monitor
  • Document and report
  • Spread the word

Reducing the Spread:
The best way to fight invasive species is to prevent them from occurring in the first place. There are a variety of simple things each of us can do to help stop the introduction and spread of invasives.

  • Plant native plants on your property and remove any invasive plants. Before you plant anything, verify with your local nursery and check out this online resource for help in identifying invasive plants.
  • Thoroughly wash your gear and watercraft before and after your trip. Invasives come in many forms – plants, fungi and animals – and even those of microscopic size can cause major damage.
  • Don’t release aquarium fish and plants, live bait or other exotic animals into the wild. If you plan to own an exotic pet, do your research to make sure you can commit to looking after it. Look into alternatives to live bait.

Monitoring:
The Lake Hopatcong Foundation Water Chestnut prevention brochureInvasive plant monitoring is one of the most valuable site­-level activities people can support. Contact your local watershed organizations to inquire about watershed monitoring volunteer opportunities. For example, the Lake Hopatcong “Water Scouts” program was established to seek out and remove any instances of the invasive water chestnut species.

If you are a lake or watershed manager, the best way to begin an invasive plant monitoring project is with an expert invasive plant survey to determine which invasives are most likely to be problematic in your watershed and identify the watershed’s most vulnerable areas. Contact us to learn more.

 

Documenting and Reporting:
It’s important to learn to identify invasive species in your area and report any sightings to your county extension agent or local land manager. For example, in New Jersey there is the Invasive Species Strike Team that tracks the spread of terrestrial and aquatic invasives and works with local communities in the management of these species. Additionally, consider developing a stewardship plan for your community to help preserve its natural resources. Princeton Hydro’s team of natural resource scientists can help you get the ball rolling by preparing stewardship plans focused on controlling invasive species and protecting the long-term health of open spaces, forests habitats, wetlands, and water-quality in your community.

Spreading the word:
Many people still don’t understand the serious implications of invasive species. Education is a crucial step in stopping the spread of invasives, which is why it’s so important to talk with your neighbors, friends and family about the hazards and ecological/economic impacts of invasive species.

Also consider talking with your community lake or watershed manager about hosting an educational workshop where experts can share their knowledge about invasives specific to your area and how best to address them. Princeton Hydro’s Director of Aquatic Programs Dr. Fred Lubnow recently gave a presentation to the Lake Hopatcong Foundation titled, “Invasive Species in Watershed Management.” View it here.

 

We encourage you to share this article and spread your invasive species knowledge so that together we can help stop the introduction and spread of invasive species.

2018 NJ Land Conservation Rally

Last week, the New Jersey Conservation Foundation held its 22nd Annual NJ Land Conservation Rally, a one-day educational conference inviting people to come together around the theme of “preserving open space and farmland in New Jersey.” The conference included 26 training workshops, five roundtable discussions, exhibitors, and a thought-provoking, inspirational keynote address.

“The Nature of Americans” Keynote Address

The keynote was given by David Case, co-author of “The Nature of Americans National Report: Disconnection and Recommendations for Reconnection,” an unprecedented national study of Americans’ relationship to nature. The study, which included 12,000 adults, children between 8 and 12, and parents, reveals an alarming disconnection to nature, but also uncovers widespread opportunities for reconnecting and provides actionable recommendations to open the outdoors for all.

One key finding of the study was that many people reported having meaningful social experiences in nature, but that many people feel “authentic” nature is too far away, expensive, and inaccessible. However, connecting with nature, along with family or friends, can be as simple as going on a walk in the neighborhood or planting flowers together. As David emphasized in his presentation, if used effectively, the findings from this study can push everyone towards a better relationship with nature, which will in turn create a better tomorrow for future generations.

Scroll down to learn more about David. 

Princeton Hydro, a proud sponsor of the rally, gave two presentations during the conference: “Recognizing The Power of Dam Removal To Reconnect & Restore Our Ecosystem” and “Nonprofit Social Media Hacks.”

“Recognizing The Power of Dam Removal To Reconnect & Restore Our Ecosystem”

This presentation, which was given by The Nature Conservancy’s River Restoration Manager Beth Styler Barry and Princeton Hydro’s Director of Engineering Services Mary Paist-Goldman, P.E., posed a critical and complicated question to workshop participants: As the dams in our country age, should we continue to repair and maintain the dams or should we remove them?

The decision for dam owners and communities often comes down to several factors: current use, cost, and the potential environmental impacts and/or ecological benefits of removal. Dam removal can help restore the river and reconnect the floodplain, yet it’s often a complicated process. Beth and Mary, who are experts in dam removal and restoration, shared with workshop participants the most effective ways to approach a comprehensive, all-inclusive dam removal in New Jersey, with particular emphasis on the Musconetcong Watershed. The presentation reflected the presenters’ deep understanding of how to best restore complexity and dynamic function to river systems while incorporating the community’s concerns.

Scroll down learn more about the presenters.

Nonprofit Social Media Hacks”

Designed for social media beginners and experts alike, this presentation, by NJ Land Rally Planning Committee member Lindsay McNamara and Princeton Hydro’s Communication Strategist Dana Patterson, covered cross-channel techniques to help organizations increase engagement, event attendance, and social buzz.

The 30 participants attending the workshop received recommendations on thorough, but free social media management tools, and learned how to efficiently measure social media analytics on a regular basis, utilize apps for creating polished graphics and content for social media, develop strategies for curating content from supporters and volunteers, and the no-hassle way to add Instagram takeovers to a communications calendar.

For a free presentation download, click here! And, scroll down to learn more about the presenters.

Presenter Bios:

Learn more about Keynote Speaker David Case:
Dave launched DJ Case & Associates in 1986 based on the premise that there is a need to apply the art and science of communication disciplines to the critically important science of natural resource conservation and environmental protection. Since that time, he has worked with nearly every state and federal natural resources agency in the U.S. Dave’s early-career work as a biologist and then media personality opened his eyes to the importance of communication disciplines to achieving conservation goals. He worked for the National Park Service on a remote, forested island in Lake Michigan as part of his master’s work to study impacts of deer overabundance. But, controversy surrounding the management of the island’s deer herd gave Dave a crash course on the “people” side of wildlife management. He took a position with the Kansas Department of Wildlife and Parks and soon was appearing on weekly radio and TV programs, speaking to civic organizations and schools and learning both the art and science of communications. Dave holds a bachelor’s degree in forestry from Purdue University and a master’s degree in wildlife ecology from the University of Michigan.

Learn more about Mary Paist-Goldman, P.E. of Princeton Hydro:
Mary Paist-Goldman has nearly 20 years of experience in water resource engineering. She currently serves as Director of Engineering Services for Princeton Hydro. In her role, she coordinates all engineering services provided by the company. Her attention to detail and creative eye leads to out-of-the-box solutions to complex problems. She has expertise in the fields of stormwater management, regulatory compliance, stream restoration, dam removal, wetland mitigation, and wastewater management. She is a licensed Professional Engineer in four states.

Learn more about Beth Styler Barry of The Nature Conservancy:
Beth Styler Barry joined The Nature Conservancy in October 2016 as River Restoration Manager. She previously served as Executive Director of the Musconetcong Watershed Association, where she worked with landowners and private, state and federal partners on the removal of five dams and other restoration issues on the Musconetcong River. She is now working on the Columbia Dam Removal on the Paulins Kill and a wetlands restoration project in the Hyper Humus Wildlife Management Area. Beth has more than fifteen years’ experience in watershed education and protection issues including work with municipal, county, state and federal government partners.

Learn more about Dana Patterson of Princeton Hydro:
Dana Patterson is a passionate environmental communicator with a strong mix of diverse stakeholder engagement experience and values-based communication strategy. She recently earned her M.E.M. from Yale F&ES and has held a variety of digital media positions including Yale Program on Climate Change Communication, Yale Environment 360, and National Audubon Society. Dana has 5+ years of NGO experience empowering environmental justice communities and currently serves as Princeton Hydro’s Communications Strategist.

Learn more about Lindsay McNamara of the NJ Land Rally planning committee:
Lindsay McNamara is an environmentalist, a birder and blogger, and a member of the NJ Land Rally planning committee, Bergen County Audubon Society, and NJ Emerging Conservation Professionals. Over the last six years, Lindsay has served as a digital media specialist in the environmental nonprofit and higher education sectors. She holds a B.A. in Environmental Studies from the University of Delaware and is pursuing her M.A. in Public and Organizational Relations at Montclair State University.

This Month’s Events: March Update from Princeton Hydro

Princeton Hydro is proud to participate in a number of exciting conferences throughout March. The conferences, which take place in Pennsylvania, New Jersey and Virginia, cover a wide variety of topics centered around protecting water resources.

March 2: New Jersey Conservation Rally

The 22nd Annual NJ Land Conservation Rally is a one-day educational conference about preserving open space and farmland in New Jersey. The event consists of training workshops, roundtable discussions, a keynote speech from David Case, author of “Nature of Americans,” exhibitors, and a farmers market.

Princeton Hydro, a proud sponsor of the rally, is giving two presentations:
  • “Recognizing The Power of Dam Removal To Reconnect & Restore Our Ecosystem”
    The Nature Conservancy ’s River Restoration Manager Beth Styler Barry and Princeton Hydro’sDirector of Engineering Services Mary Paist-Goldman , P.E. will present the most effective ways to approach a comprehensive, all-inclusive dam removal in New Jersey, with particular emphasis on the Musconetcong Watershed.
  • “Nonprofit Social Media Hacks”
    Rally Planning Committee member Lindsay McNamara and Communication Strategist for Princeton Hydro Dana Patterson present ways to punch up your social media presence. The course is designed for social media beginners and experts alike, and will cover cross-channel techniques to help increase engagement, event attendance, and social buzz around your organization.

LEARN MORE & REGISTER

 

March 4 – 6: Virginia Water Conference

Held by the Virginia Lakes and Watershed Associationand the Virginia Floodplain Management Association, the Virginia Water Conference will host 400 participants, and will include exhibits and breakout sessions on topics ranging from floodplain management to dam safety to water resource engineering.

Princeton Hydro’s Dr. Fred Lubnow, Director of Aquatic Programs, and Michael Hartshorne, Senior Limnologist, are conducting a Water Quality and Quantity breakout session titled,  “A Limnological Assessment of a 250-Acre Impoundment in Virginia for the Consideration of Nutrient Inactivation.”

LEARN MORE & REGISTER

 

March 7 – 8: PA Lake Management Society Conference

The Pennsylvania Lake Management Society is hosting its 28th annual conference during which lake professionals, students, recreation enthusiasts, lakeside residents and community members will come together to explore a variety of topics related to managing lakes and reservoirs. Visit the Princeton Hydro booth to discuss the latest advancements in pond, lake and watershed management.

The conference offers a collection of professional presentations, workshops and panel discussions. Princeton Hydro is giving two presentations during the conference:

  • “Continued Management of Hydrilla in Harveys Lake, Luzerne County, Pennsylvania”
    Lead by Michael Hartshorne, Senior Limnologist, and Scott Churm, Associate: Director of Aquatic Operations
  • “Conducting a Nutrient Inactivation Treatment for Internal Phosphorus Load Control for a Small Glacial Lake in Northern Pennsylvania”
    Lead by Dr. Fred Lubnow, Director of Aquatics Programs

LEARN MORE & REGISTER

 

March 10: Schuylkill Watershed Congress

The Watershed Congress is an annual event that seeks to advance the best available information and techniques for protecting and restoring watersheds by combining science, policy, and practical applications into one program.

The one-day conference offers a keynote discussion on Landscape-Scale Forest Loss in the Delaware Basin, 21 concurrent sessions covering a broad range of watershed topics, poster sessions and exhibits. Dr. Fred Lubnow‘s breakout session, titled “Ecology/Management of Cyanotoxin Producing Blue-Green Algae in the Schuylkill River,” reviews the basic ecology of nuisance blue-green algae and how to monitor, manage and prevent cyanotoxins particularly in potable water supplies.

LEARN MORE & REGISTER

 

March 15: Land Ethics Symposium

The theme for this year’s 18th Annual Land Ethics Symposium, which is presented by Bowman’s Hill Wildflower Preserve, is “Creative Approaches for Ecological Landscaping.” The conference will focus on ways to create low-maintenance, economical and ecologically balanced landscapes using native plants and restoration techniques.

Participants can take part in presentations, for which continuing education credits are available, on topics, including Installation and Management of Stormwater Basins, Landscaping for Carbon Storage and Resilience, and Watershed Restoration. The conference also offers a variety of networking events and an exhibitor hall. Princeton Hydro, a “Friends Sponsor” of the event, will have an exhibitor table. We hope to see you there!

LEARN MORE & REGISTER

 

March 19: SAME Philadelphia Post Small Business Conference

The Philadelphia Post is hosting its 12th Annual Small Business Conference and Industry Day, which aims to promote engagement between agency, industry, and small businesses. The program consists of networking events, small business exhibits, a variety of speakers and much more.

The Society of American Military Engineers (SAME) gives leaders from the A/E/C, environmental, and facility management industries the opportunity to come together with federal agencies in order to showcase best practices and highlight future opportunities for small businesses to work in the federal market. If you’re in attendance, please stop by the Princeton Hydro booth.

LEARN MORE & REGISTER

Habitat Fragmentation – Culvert Blockages and Solutions

Capture

Culvert that is “perched” due to scour by high velocity flows through the pipe. ©Princeton Hydro.

The Bucks County Chapter of Trout Unlimited (Pennsylvania) and the Cooks Creek Watershed Association were featured in the Summer 2013 edition of Trout magazine, TU’s national publication, for their culvert inventory work in the Cooks Creek watershed.  Princeton Hydro was glad to assist via directly investigating and training of volunteers to inspect and document potential culverts in need of retrofit.  Princeton Hydro also completed design concepts and opinion of costs for two example culverts.  Identified culverts in need of retrofit will help the creek’s wild brown and brook trout.  Princeton Hydro based the training on the Vermont guidelines for rating culverts for pass-ability.  In this small watershed a total of 97 culverts were identified with 32 of them as potential barriers, and 11 identified as “high priority” in need of retrofit.

Why worry about culverts, you say?

One of the most unforeseen danger to the biodiversity in our river networks is habitat fragmentation through un-passable culverts throughout the United States.  While blockages via dams number upward of 100,000 or so, the blockages created by ecologically and biologically inefficient culverts is likely to number in the millions.   The majority of these culverts are located in headwater areas of rivers, which entail greater than 50% of most river miles in a watershed; a large cumulative impact.  As a result, native key headwater species such as brook trout (Salvelinus fontinalis) in the East and cutthroat trout (Oncorhynchus clarkii) in the West have had their historic ranges reduced to a fraction of their former extent.

Historically, culverts were designed by civil engineers to maximize flow capacity and minimize pipe size in order to create the most economical structure for developers, transportation authorities, and municipalities.  The unfortunate by-product of such a design approach is that water velocity through culverts is extremely high, often running in supercritical flow, even during base flow conditions, and the smooth and featureless surfaces in the structure make it extremely difficult to navigate.  To add insult to injury, the high velocity flows also scour and erode the stream channel immediately downstream of the culvert, leaving the pipe too high out of the new channel (“perched pipes”) for organisms to pass.  Downstream water dependent organisms cannot pass upstream to new habitat, and those populations upstream become extirpated due to downstream migration and mortality, and the lack of an ability to return or be replaced.  A study of impacts of fragmentation on brook trout is ongoing by the USGS Conte Anadromous Fish Research Center (USGS CAFRC) and others, and a study recently completed documented the impacts of fragmentation of local populations provides an informative view of the blockage potential of culverted streams.

There is hope in the re-connection of stream habitat through new research and initiatives developed since 1999.  One such approach is through the Stream Simulation design originally developed in its present form at the Washington State Department of Fish & Wildlife and adopted by the US Forest Service, US Fish and Wildlife Service, as well as others, and was also adopted shortly thereafter and refined by the University of Massachusetts, Amherst Extension (Stream Continuity model) for use in Northeastern States (initially in the Massachusetts River and Stream Crossing Standards, and then adopted in similar form by surrounding states).  Through the Stream Simulation/Continuity method, a culvert is not simply measured in terms of hydraulic efficiency, but also in terms of ecological and biological efficiency.

In the most basic terms, Stream Simulation (Continuity) requires a crossing that has a minimum width of the bankfull flow of the natural channel upstream and downstream, plus more width to allow passage of terrestrial organism passage such as reptiles and amphibians (in the UMASS model the increase in width is 20% wider than bankfull, but in the current Washington State model they use 20% plus 2 feet).  The other part of the design requirement is an opening area to length ratio to allow the maximum amount of natural light penetration into the culvert (openess ratio), as many organisms, such as fish, are too intimidated to travel through dark culverts.  Other design requirements include the use of slopes and velocities that allow for fish passage, and roughness (i.e. placement of natural substrate) to also slow down the flow.

The key challenge for the retrofitting of culverts to be more passable is cost.  As with any civil engineering project, the larger it is, the more expensive.  To replace a 36 inch diameter culvert with a 10-14 foot wide structure could increase the cost by 10-fold.  However, there are ways in completing an economic analysis to justify the costs.  For example, most culverts were historically only designed to pass storms up to the 25-year event, but in even more cases, never were sized by engineers.  A larger culvert will increase its capacity and reduce overtopping events that would require road closings and worse, cause the roadway to collapse.  Road closings require emergency management and road crews to set up detours and slowing down commerce, or worse require repetitive reconstruction efforts that, over time, may exceed the cost of installing a Stream Simulation designed culvert.

DSCN2588

Same culvert as in photograph above, after the retrofit using Culvert Simulation. ©Princeton Hydro.

Other ways of encouraging installation of these larger and passable culverts is through the permitting process.  In New England, the US Army Corps of Engineers, allows for a by-pass of a formal review for their approval if the Stream Simulation guidelines are followed. This approach can save a significant amount of time to fast-track a retrofit.  To complement the Corps’ permit facilitation process, the states of Connecticut, Massachusetts, New Hampshire, and Vermont, have developed stream crossing guidelines to meet the Corps’ permit by rule compliance.  These states have even instituted state level regulations requiring aquatic organism passage via the Stream Simulation model.

Princeton Hydro was contracted to design a culvert retrofit to replace a 36 inch diameter culvert with a 12 foot wide arch culvert on a tributary of West Brook which is being monitored as part of the USGS CAFRC research project in Massachusetts.  This retrofit will be used to assess the increase in efficiency of headwater stream accessibility by local brook trout populations.

It would appear that the Stream Simulation or Continuity model is catching on, however, there needs to be more outreach and changes to existing rules in other regions of the US.  Further studies, such as that being conducted by USGS and their partners, will determine the true benefits of increasing culvert fish passage efficiency and bolster the economics of protecting fish populations for future generations.
——-
Geoffrey M. Goll, P.E.
Vice President and Founding Partner

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