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Invasive Species/Vegetation Management

Case Studies

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Listed below are examples of success stories, best practices, and/or innovative tools/approaches. This section will grow as entries are submitted or links to other sites with useful examples are provided. If you believe your agency has utilized a best practice/approach that others could learn from, please submit a short description to AASHTO (including any pertinent links) on the Share Info with AASHTO form.  Please note that currently submissions are only being accepted from governmental entities.

The following resources provide case studies on invasive species and vegetation management topics:

Colorado

Colorado Landscape Architecture Manual Provides Guidance, Best Practices

At the Colorado Department of Transportation, effective landscape architecture provides benefits beyond just a pretty view.

In fact, CDOT regards one of the major focuses of landscape architecture to be the “protection and enhancement of natural systems affected by the transportation system.”

To ensure this, the transportation agency recently issued the CDOT Landscape Architecture Manual (2014). The manual, which took about two years to write, brings together all information relevant to highway landscape design including aesthetic, sustainability, environmental, and landscape considerations. 

Glenwood Canyon is an example of Western Slope Canyons and Valleys, one of CDOT’s five designated design zones. (Photo: CDOT)

The intent of the manual is to ensure that federal and state requirements are addressed uniformly across the agency’s decentralized regions and the state’s diverse geography. “Transportation design is required to fit [in with] the existing physical environment using context sensitive design and practices,” according to Mike Banovich, a landscape architect who has been with CDOT for 25 years.

Banovich said CDOT undertook creating the manual because it recognized the need to create guidance that would “improve program quality and compliance.”

Focus on Context

The manual presents landscape architecture as a component of the entire planning and design process for transportation projects, using a multi-disciplinary approach. There is a “direct relationship” between design and place, the manual says.

With that in mind, the manual provides broad-ranging guidance on how to plan and design landscapes that appear natural, conserve water, protect resources, and are sustainable for the life of the road or highway.

The intent is to “expand transportation design decisions beyond strictly functional and engineering criteria within a Context Sensitive Solutions approach,” according to the manual.

Protecting vegetation, designing areas for new plantings, and controlling noxious weeds are key components of the landscape architect’s job and the manual discusses best practices and requirements under state and federal laws. Each of these tasks involves many variables, not the least of which are climate and geography.

Use of ‘Design Zones’

The identification of design zones is “critical to creating a relationship between transportation and landscape,” the manual said.

According to the manual, the state of Colorado encompasses five design zones:

  • High Plains (east of Denver),
  • Front Range Urban (Denver and its suburbs),
  • Southern Rocky Mountain,
  • Western Slope Basin, and
  • Great San Luis Valley (at the border with New Mexico).

“By understanding the characteristics of each zone, CDOT can design unified corridors with consistency and a recognizable sense of place in each zone,” the manual said. For example, “the road alignment should respond to the dominant land form of a zone while the plant palette should be derived from plant species native to the zone and micro-climatic conditions. Details, such as colors and textures, applied to transportation facilities could be reflective of the cultural and landscape context.”

The design zones are consistent with the ecoregions described in the Federal Highway Administration’s Vegetation Management: An Ecoregional Approach handbook, issued in 2014. The handbook defines ecoregions as areas of similar geographic, vegetative, hydrologic, and climatic characteristics, and emphasizes the use of native plants along roadsides to reduce maintenance costs, provide better erosion control, and create ecological diversity.

Native Plants a Requirement

At CDOT, a nearly four-decade-old policy requires department personnel and contractors to use native or dryland adaptable plants on all landscaping projects. To implement that policy, the manual directs landscape architects to preserve or salvage existing vegetation in the project area. If that is not practical, the area must be replanted with native species and must follow the principles of xeriscaping, a technique that reduces or eliminates the need for irrigation.

“Xeriscaping is very important [at CDOT] because Colorado is primarily a semi-arid cold desert experiencing drought and extreme weather fluctuations,” Banovich said. “CDOT’s objective is to use native plants adapted to our arid climate in non-irrigated conditions.”

Additionally, the manual directs that existing topsoil must be preserved and reused, which includes stockpiling during the construction phases of projects. Topsoil can be imported from elsewhere only as a last resort.

Threats from Invasive Species

Like many states, Colorado faces threats from invasive plant species that diminish the value of cropland, rangelands, and native habitat. The state has enacted legislation that identifies noxious weeds that are to be contained, controlled, or eliminated. Also, state law for the protection of stream-related fish and wildlife requires the department to consider noxious weed eradication while planning for construction projects in riparian zones, according to the manual. Additionally, construction equipment and stockpiled topsoil must be kept free of invasive weeds.

Vegetation planted or maintained in highway rights-of-way must not create unsafe conditions for drivers and vehicles. The manual discusses the importance of maintaining sight distances for drivers, having trees and other large plantings set back from the roadway, and avoiding conditions where too much shade can cause visual hazards or allow ice to form on road surfaces. Additionally, newly constructed features in rights-of-way should include landscape designs that minimize rainwater runoff and the need to irrigate. 

Role of the DOT Landscape Architect

In addition to laying out the standards and best practices, the manual provides information on the role of the landscape architect in the transportation department. The landscape architect is a valuable participant in projects from the early planning stages through the National Environmental Policy Act (NEPA) process and even after completion, according to the manual. Many state departments of transportation such as CDOT have landscape architects on staff.

The landscape architect’s role is “to act as the design liaison between environmental specialists and engineers…by incorporating environmental needs and requirements into the project objectives,” Banovich said. Additionally, stormwater management and water quality have “become important components” of the landscape architect’s job in recent years, Banovich said.

According to the manual, planting design concepts are a result of the landscape architect’s training in elements such as color, form, line and texture. The placements of plantings on the highway right of way serve to:

  • Protect against erosion.
  • Minimize water use through the use of native drought tolerant species, mulches, and the use of irrigation systems designed for low precipitation systems.
  • Promote stormwater reduction runoff practices via interception and root infiltration.
  • Screen undesirable views from the highway and screen highway from adjacent land owners.
  • Guide traffic.
  • Avoid root or foliage contact from deicers.
  • Minimize maintenance requirements.
  • Provide shade at scenic overlooks or at rest areas.
  • Frame and emphasize a view.
  • Screen highlight glare.
  • Mitigate impacts to surrounding communities.
  • Reduce driver monotony.
  • Provide wildlife habitat.
  • Salvage, protect or reuse existing vegetation, when possible.
  • Mitigate for wetland/riparian impacts.

Lessons Learned

For other DOTs considering creating their own landscape architecture manual, Banovich suggests obtaining “concurrence from DOT leadership” while also involving environmental resource specialists.

Additionally, it is important to “define the use of the manual in a policy objective which in turn will justify the use of the manual” as a part of the DOT’s operational procedures, Banovich said.

For more information, link to the CDOT Landscape Architecture Manual or contact Mike Banovich, RLA, CDOT Ecological Design Unit Manager, at michael.banovich@state.co.us

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Kansas

Kansas DOT Roadside Management Policy Evident as Wildflowers Bloom

The Kansas Department of Transportation’s successful roadside management policy is getting some well-deserved recognition each spring, as motorists enjoy the sight of pink evening primrose and other native wildflowers in full bloom along the state’s highways.

KDOT’s roadside management policy encourages growth of native grasses and wildflowers on more than 150,000 acres of state-owned right-of-way.

KDOT environmental scientist Scott Shields said the agency began including native wildflowers in its seed mix in 2003-2004, and began to increase its focus on the native landscape even before that.

In 2008, KDOT staff and partners from conservation groups and the Kansas Department of Wildlife and Parks formed the Roadside Vegetation Task Force to focus on best practices for managing the state’s rights-of-way.

The resulting policy calls for seed blends that include native plants and wildflowers, use of certified mulch to prevent the spread of weeds, reduced mowing, and storing and replacing topsoil disturbed during construction.                   

Mowing Policy Revised

Most recently, KDOT revised its mowing policy, a practice that saves on fuel and labor costs while benefiting the environment. Mow-outs of the full right-of-way are done only once every four years instead of every three years, and are timed so the mowing does not interfere with late fall wildflower seed propagation. For the shoulders, mowers make only one pass and let the grass grow to 12 inches before cutting.

The agency also is stressing the importance of topsoil, requiring contractors to strip and store topsoil removed during construction. This practice helps to reestablish native plants and helps to control erosion.

Other practices include spot spraying rather than broadcasting of herbicides whenever possible.

Shields said the roadside vegetation management practices have been a big success. He noted the importance of educating maintenance and construction workers so that those in the field know what to do.

“As a result of these and other practices, we’ve reduced maintenance costs, provided erosion control, taken advantage of the vegetation’s natural filtration system and beautified our highways,” Shields said.

KDOT’s Northeast Kansas District Engineer Clay Adams, who led the task force, also noted the importance of such practices.

“Together we’ve developed a wiser approach to roadside management, we’ve found a way to stretch KDOT’s maintenance budget, and we now have guidelines that will enhance the natural beauty of our state,” Adams said.

The success of the policy can be seen each spring when native wildflowers – including purple rose verbena, white and yellow ox-eye daisy and yellow Missouri primrose – beautify the roadway while providing natural erosion control and filtration and habitat for pollinators and other wildlife.

For more information on KDOT’s roadside management practices, link to KDOT’s Roadside Management Brochure or contact Scott Shields at scottsh@ksdot.org.

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Minnesota

Six State DOTs Join Forces to Build ‘Monarch Highway’

A coalition of six state transportation agencies are working together to help monarch  butterflies on their migratory journeys by establishing a continuous “Monarch Highway” stretching north-south along Interstate 35.

Departments of Transportation in Iowa, Kansas, Minnesota, Missouri, Oklahoma and Texas are working to improve habitat along the corridor in each state. The state agencies along with the Federal Highway Administration signed a Memorandum of Understanding in the spring of 2016 in which they pledged to collaboratively implement pollinator habitat best practices and promote public awareness of the need to conserve pollinators. The agencies have agreed to develop educational materials together and assist each other as they “inventory, protect, plant and manage pollinator habitats and develop strategies for pollinator-friendly seed mixes.”

Actions to preserve monarch butterflies are becoming more vital. The species has declined by 80 percent over the past two decades due to factors such as habitat fragmentation and herbicide decimation of milkweed plants, which are its larvae’s only food source. The U.S. Fish and Wildlife Service must determine by June 2019 if the monarch butterfly should be listed as endangered under the Endangered Species Act. If the species is listed, its presence throughout the I-35 corridor would trigger additional requirements for federally-funded projects.  

 
 Monarch butterfly on milkweed. Photo: U.S. Fish and Wildlife Service

“We all are already carrying out practices that benefit pollinators such as reduced mowing, targeted herbicide use, and planting native vegetation seed mixes,” said Tina Markeson, the Monarch Highway Project Chair and Roadside Vegetation Management Supervisor at the Minnesota Department of Transportation (MnDOT). “But having a multi-state effort brings added benefits.”

One of the key benefits, she said, is the ability to apply for grants as a group, which is attractive to funders looking for broad impact. Also, each state is better positioned for individual grants due to the inherent credibility that comes from participation in a collaborative project. Yet another benefit is the opportunity to discuss what works and what doesn’t. The single message focus also gives added clout and enables common educational materials to be developed at less cost.

Stepping Up Existing Efforts

Individual states have not received specific funding for their Monarch Highway work, nor is there external financial support to administer the initiative, said Markeson.  However, participants will be tweaking or stepping up what they already are doing. Her agency, for example, has been planting native seed mixes for about 25 years.  Though more expensive than non-native mixes, native plants offer multiple advantages, such as strong root systems for erosion control and water filtration, strong stalks that act as snow fences, and reduced long-term maintenance costs.

To create a baseline and determine what is needed next, each state is carrying out an internal analysis of its own current practices along I-35.  Potential actions by states may include:

  • adding or increasing milkweed in seed mixes;
  • cutting back mowing;
  • increasing plantings in targeted areas to reduce habitat fragmentation; and
  • carrying out prescribed burns as a vegetation maintenance tool.   

Geographic differences also will affect individual state approaches.  In Minnesota, for example, the I-35 corridor includes deciduous and coniferous forest as well as prairie.   One component of its approach will be to assess its current stock of flowering trees and shrubs and make pollinator-friendly adjustments as needed.  And some of its educational materials will include a reminder that other types of vegetation, not just wildflowers, are part of the solution.

The six-state group plans to step up its collaborative efforts to include regular teleconference calls and annual face-to-face meetings. The Monarch Highway Project Chair position likely will change every two years and by-laws will be developed.  Rest areas likely will be the initial focus, with demonstration plots and educational materials made available in all six states.  A mock-up of a logo is being circulated for comment, and funding opportunities are being actively explored.

To magnify their work, all six states are working in partnership with other state agencies as well as nonprofit groups.  For example, Markeson said her agency is working with the Minnesota Department of Natural Resources and the Board of Water and Soil Resources to coordinate requests for the 30 different types of seed mixes it uses across the diverse biomes found throughout the state.  And in Texas, which is responsible for almost double the number of I-35 miles found in the other states, TxDOT will draw on existing resources such as the Texas Monarch and Native Pollinator Conservation Plan.

History of Initiative

Multiple government actions have provided strong justification for the initiative.  In 2014, President Obama issued a memorandum calling for increased federal agency efforts to preserve declining pollinators. The following year, the National Strategy to Promote the Health of Honey Bees and Other Pollinators was released.  Both documents call out the I-35 corridor as a key focal point.

In addition, in 2015 the White House Office of Science and Technology Policy and U.S. DOT partnered to sponsor a summit of state transportation leaders to advance pollinator habitat.  And the Fixing America’s Surface Transportation (FAST) Act contains provisions for the U.S. DOT, in conjunction with willing state DOTs, to encourage habitat development for monarch butterflies and other pollinators. In addition to these national measures, state-specific directives call for reversing pollinator decline, such as Executive Order 16-07 issued by Minnesota Governor Mark Dayton in August 2016. 

While these recent actions have helped to create a strong framework, the roots of the Monarch Highway project actually date back several decades to another I-35 initiative.  In 1993, the FHWA provided funding to the same six DOTs to create the Prairie Passage Program, with I-35 as its backbone. 

Overcoming Challenges

Despite the pluses, Markeson said, Monarch Highway participants likely will face several challenges as they pick up the pace in 2017.  First, while they already are carrying out pollinator-friendly practices, factors such as additional staff time and a greater proportion of native seed mix investments could add to costs at a time when some state DOT budgets are shrinking.  

An additional obstacle may be that of ensuring continued commitment to maintaining the good work once it is in place.  As Markeson explained, “It tends to be easier to find funding for planting than it is for maintenance.  We have to make sure that what we are doing will be sustained.”

Yet another challenge may be to fully account for the effects of altering current practices, especially in terms of agricultural interests.  For example, some farmers who use roadside mowings for cattle feed have raised concerns about including milkweed in the seed mix.  

Advice for other DOTs

To maximize chances for success in a multi-state initiative such as the Monarch Highway, Markeson offered four tips:

  • Find an internal agency champion if possible; in this case, MnDOT Commissioner Charles Zelle has been an outspoken proponent;
  • If there is a related initiative from the past that can help provide a foundation, draw upon it;
  • Continue to exchange information with the other states to build on successes and lessons learned; and
  • Develop and maintain close communication with materials providers, in this case native seed mix producers, so that they have the incentive to develop such mixes and have them available when needed.

What’s Down the Road for the ‘Monarch Highway’?

The ultimate goal is a cost-effective, thriving transportation corridor that serves the needs of both its human and its pollinator species travelers.  But ultimate success for pollinators will depend upon a much larger realm of supporters than just these six agencies.

“Many others need to be involved as well,” Markeson said. “We will be doing our part, but dedicated efforts should be underway across the country as well as up into Canada and down into Mexico.  The rewards on many levels are indisputable.”

For more information, contact MnDOT’s Tina Markeson at Tina.Markeson@state.mn.us or access the Monarch Highway memorandum of understanding. Information on additional transportation-related efforts to protect pollinators are detailed on the FHWA’s Pollinator web page.

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Virginia

VDOT Program Aids Pollinators While Supporting Transportation Goals

The Virginia Department of Transportation (VDOT) is implementing a Pollinator Habitat Program along the state’s highway system that provides much-needed waystations for monarch butterflies and other dwindling pollinator species.  Moreover, according to agency officials, the program is entirely consistent with the department’s transportation priorities.

“Our savings on mowing costs alone will be significant,” said Diane Beyer, State Vegetation Management Planner for VDOT’s Maintenance Division. “Currently, each roadside mowing cycle costs approximately $12 million. Under the program, our goal is to reduce mowing frequency from three times a year to once a year.”

 
 Volunteers plant natives at I-95 meadow restoration. Photo: VDOT

 Under the program, Beyer explained, stretches along the state’s highways and at rest areas are being planted with native vegetation that provides food and habitat for pollinators. The multi-colored vegetation includes species such as milkweed for monarch butterflies, asters for bees, and goldenrod for birds, bees, and butterflies.  

Beyer said the program will bring multiple transportation and environmental benefits. First, the program supports VDOT’s vision of safety while providing increased habitat areas. For example, attractive roadsides have been shown to reduce driver fatigue and improve mood; and wildflower perennials and grasses are not favored by deer, a potential driver hazard. In addition, mowing only the shoulder (and allowing wildflowers to continue to bloom) still maintains line of sight and space for motorists to pull off, and it prevents encroachment of shrubs and trees.

In addition, roadside maintenance time and costs are reduced through planting of self-sustaining, native vegetation.  The vegetation stabilizes slopes and reduces erosion; increases storm water and nutrients retention due to deep roots; and reduces other vegetation maintenance costs such as invasive species control and herbicide applications.  It also provides a smooth transition to adjacent properties.

The program also contributes to the agency’s broader Integrated Vegetation/Pest Management system through reduced use of herbicides; increased erosion, sediment and stormwater runoff control; and reduction in the presence of invasive species. An additional benefit is the increase in visual aesthetics.

Besides supporting VDOT’s transportation goals, Beyer said, VDOT’s Pollinator Habitat Program also supports the Department’s MS4 program, a critical element of Virginia's stormwater management program. On a national level, it supports FHWA’s Every Day Counts initiative though what Beyer calls its “low-tech, back to basics” approach to innovation and its focus on safety. In addition, the program aligns well with the Presidential Memorandum issued in 2014 on creating a federal strategy to promote the health of honey bees and other pollinators. 

Genesis and Development

“As it happened, the inception of our program preceded the Presidential Memorandum by several months,” said Beyer.  “The timing was very helpful to us in terms building internal support for what was viewed as a very new approach to maintenance.”

The pilot program began in the fall of 2014. Four plots were planted with plant plugs in northern Virginia, each 900 square feet and containing 13 different species. These initial plantings provided Beyer and her team with a useful means of learning what works and what doesn’t.  The plantings also provided a foundation for beginning to educate agency staff and the public about the program and the reasons behind it.

In September 2015, a 15,000 square foot meadow area was planted at a rest area on Interstate 95 (a migratory flyway), also in northern Virginia.  Three smaller plantings simultaneously were installed near the rest area building. The latter plantings serve as educational stations with interpretive signage for visitors.  A total of 8,000 nectar and pollinator plants from 23 species were planted.

Also during the fall, three areas in southwestern Virginia were planted with seeds (not plants); one of the goals was to analyze which seed mixtures and types of seed planting methods work best. In this case, the areas were medians and roadsides.  And at the end of 2015, the program moved into the western part of the state for the first time.

Plants such as this aster attract pollinators on Virginia roadsides. Photo: VDOT

 Plans call for the program to be implemented statewide. In 2016, while results from the seed-planting location are gathered, the focus will be to continue to create naturalized gardens and meadows with mature plants at state rest areas. In the meantime, interpretive signage continues to be developed and installed at existing areas. Beyer said the team will integrate solutions to challenges they faced in the early months, such as ensuring continued maintenance of the plots until the vegetation is well established.

Funding and Partners

Currently, the program primarily is funded through the purchase of the “wildflower” license plate, which will continue to be offered to drivers and is supported by the Virginia Garden Clubs. Beyer said, the newly minted “pollinator” license plate currently does not financially support the program, but a bill is being introduced in the 2016 Legislative session to remedy that and direct funds to VDOT in support of the Pollinator Habitat program. 

Partners have been essential to the program’s growth, she continued. They include Virginia Dominion Power/Dominion Trust; Valley Land; White House Office of Science & Technology; Loudoun Wildlife Conservancy; Virginia Native Plant Society; and PBS Films. These groups continue to provide needed funding, labor and materials.

Advice for Other DOTs

Beyer said other state DOTs either are planning or beginning to carry out similar programs.  Examples included a corridor restoration project from Texas to Minnesota, as well as programs in Illinois, North Carolina, Ohio, and Vermont. Part of the challenge for interstate initiatives, she pointed out, is that DOTs have varying organizational structures, which can make obtaining a multiple-state green light, as well as  ongoing cross-state coordination, challenging.

Her advice to other state DOTs contemplating a similar initiative centered on two themes: education and partnering. Educating the public is important, Beyer said, but perhaps even more critical is internal agency education, especially for two groups: upper management and the maintenance team tasked with actually carrying out the work.  As partnering goes, securing early collaboration from groups such as native plants societies, Extension Services, garden clubs and wildlife organizations is key to success. They will all help with the outreach and education of the program as well.

Finally, she urged agencies not to overlook the corporate sector: it definitely needs to be included on agencies’ teams to bring key expertise, networks, and financial support to the table. Partnerships also give others a sense of stewardship in promoting and furthering the program.

“Our organizational structure is such that safety rest areas are managed centrally, making it easier to create a consistent program face. Consistency is important in that it brands the program and makes it more comprehensible and recognizable to the public and staff. Rest areas are also an excellent way for us to educate the public about the new program and the new mowing practices and gardens,” she said.

“Education, both internally and externally is a paramount necessity in a program such as this. You want to make sure everyone comprehends the 'whys' so that support comes forth from a place of knowledge and understanding," said Beyer.

She suggested that education and outreach be an integral part of a similar program, as new techniques and ideas are not always well received when staff and the public are not included in the “whys” and allowed to ask questions.

For more information, link to Virginia DOT’s Pollinator Habitat Program website or contact Diane Beyer, State Vegetation Management Planner, VDOT Maintenance Division, at Diane.Beyer@vdot.virginia.gov.

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Washington State

Reduced Roadside Mowing Policy Promises Multiple Benefits in Washington State

Reduced fuel consumption, fewer carbon emissions, better weed control, cost savings and improved habitat for pollinators are among the many benefits of the Washington State Department of Transportation’s (WSDOT) new policy to reduce mowing on the state’s roadsides.

WSDOT’s revised mowing policy, adopted in 2015, changes the focus of roadside maintenance from aesthetics in favor of a more natural approach. 

Under the revised mowing policy, WSDOT has eliminated almost all mowing that had been conducted for aesthetic reasons in areas with wide rights of way extending beyond 30 feet from the pavement edge. The change will result in a one-third reduction in mowing for non-safety-related reasons annually, according to an agency summary. 

The policy specifies that routine mowing “will generally be limited to one pass adjacent to the paved shoulder except in rare cases where a wider annual mowing swath is necessary for safety or for specifically indicated vegetation control.”

Most areas beyond the 30-foot limit that had previously been managed with routine mowing will now be designated as “naturally managed areas” and left to grow mostly naturally, unless hazard trees or designated noxious weeds need to be controlled. Certain higher profile areas will be selectively managed as meadows where all weeds are controlled and natural succession of desirable native plants is encouraged. 

 
With the new mowing policy, areas beyond the first pass will be managed for natural succession of desirable plant species. (Photo: Washington State DOT)

In a related effort, the agency is conducting a pilot study during the summer of 2015 that will be the first published research in the country to provide a cost/benefit analysis of grazing (using goats) as a mowing tool in state highway rights of way.

All of these actions are part of a multi-year strategy by the agency to create more self-sustaining and lower-maintenance roadsides that are complimentary to the surrounding native ecosystems, according to Ray Willard, Roadside Maintenance Program Manager at WSDOT. 

Benefits of Reduced Mowing

Benefits of reduced mowing include lower fuel consumption—the department expects to save approximately 2,500 gallons per year of diesel fuel for mowing equipment—and an associated reduction of 23 metric tons in CO2 emissions.

WSDOT also expects to save money in labor and equipment costs. The department will be able to divert its maintenance crews to higher priority work and also switch from using large tractors with wide mowing decks to smaller, more efficient and versatile mowers. Overall, WSDOT expects to save approximately $550,000 each year in mowing costs.

The revised policy will also provide more effective nuisance weed control in designated high profile areas. In freeway interchanges and designated scenic corridors, WSDOT will carefully coordinate mowing patterns and timing with other vegetation management treatments with the goal of removing unwanted nuisance weeds and trees and encouraging more desirable native roadside plant communities over a series of years.

Looking out for Pollinators

Another benefit of reduced mowing is improved habitat for pollinators such as honey bees and butterflies, a topic that has recently taken on national significance. In June 2014, President Barack Obama issued a memorandum directing federal agencies to take actions to protect pollinator species, including calling on the Department of Transportation to work with state DOTs to increase pollinator habitat along roadways.

Roadsides can offer pollinators improved forage for food, breeding, or nesting, and help link fragmented habitat, according to a literature review released by the Federal Highway Administration in May 2015. The report supports the development of best management practices for pollinator habitat protection and enhancement in highway rights of way.

The Transportation Research Board is also planning a webinar on promoting the practice of integrated vegetation management and managed succession over routine mowing, according to Willard, who also serves as research coordinator for TRB’s Roadside Maintenance Operations Committee (AHD50).

Federal leadership together with the agency’s executive leadership on the pollinator issue were contributing factors leading to WSDOT’s revised mowing policy, according to Willard. “What we have now is really good motivation from the top down that we should be taking a more natural approach to managing roadsides,” Willard said.

He also pointed to a recent FHWA publication, Vegetation Management: An Ecoregional Approach, which he said laid the groundwork nationwide for this new approach. The FHWA document, described in this agency article, has been distributed but not yet posted online by the agency.

System Tracks Acres Mowed

To monitor progress in implementing the new policy, WSDOT maintenance staff will be deploying the department’s new Highway Activity Tracking System (HATS).  The system allows field staff to document their vegetation management activities in greater detail using tablet computers and geographic information system mapping.

In the past, documenting the number of acres mowed was “kind of a wild guess,” according to James Morin, Maintenance Operations Manager at WSDOT. “You knew how wide the mower was and roughly how far you travelled.” But under the new system “as long as [maintenance crews] turn on their iPADs, they’ll know exactly how many acres they mowed.”

HATS will be integral to implementing the revised mowing policy because it will allow the department to document savings in terms of fuel consumption, carbon emissions and other lifecycle costs, according to Willard. 

Public and Agency Outreach

As roadsides begin to take on a more natural and less manicured appearance, people will continue to question and debate the merits of visual quality vs. environmental sustainability, Willard said. “It is important that we collect and maintain clear scientific evidence of the overall environmental benefits from mowing less,” he added

The popular desire to see neatly mowed roadsides carries over into the culture and historic practice of highway maintenance, where agencies receive positive feedback when the roadsides are mowed, Willard said.

There’s also the potential for political pressure on state DOTs to mow for aesthetics in the name of tourism, quality of life, or for the benefit of neighboring businesses, according to Willard.

To help educate the public, WSDOT is developing a four-page color print folio on the revised mowing policy and is developing similar language to feature on its website.

To help convince the agency’s staff, managers have focused on the benefits to the natural environment. “The maintenance employees take a lot of pride in a neatly cared-for roadside, so it’s really [about] shifting from seeing the roadside as a pretty thing to seeing it as a beneficial thing to the natural environment,” Willard said.

Where environmental considerations alone might not convince staff, the economic savings are also compelling, according to Morin. “If we can have a native roadside that’s high functioning, we don’t typically have as many weed issues and it doesn’t cost us as much in terms of effort or money to maintain,” Morin said.

An important factor in WSDOT’s success in implementing the new policy has been having planning guidelines and objectives that are consistent statewide, yet still offer flexibility to the local maintenance areas, according to Willard. For WSDOT this has involved updating the integrated roadside vegetation management plans for each of the state’s 24 maintenance areas to incorporate reduced mowing on a case by case basis.

Another key strategy within the new policy is encouraging local governments to “adopt” freeway roadsides through their cities if they desire a more park-like appearance.  WSDOT has developed permits to allow this type of local participation where appropriate.

Testing Goats as ‘Biological Mowers’

In a related effort to evaluate a more natural approach to vegetation management, WSDOT is conducting a pilot project using grazing goats as a mowing tool on state highway rights of way.

“Goats are basically biological mowers,” Willard said, and can perform a similar function as mechanical mowing but without burning fossil fuels and generating carbon emissions. Another advantage is that some weed seeds are sterilized as they pass through a goat’s digestive system, allowing for more effective weed control than mechanical mowing. Goats can also easily access steep and uneven terrain.

However, concerns over the use of grazing in highway applications include higher costs associated with fencing, watering and supervising the animals; liability; and potential distractions to drivers, according to an agency summary of the research.

While there has been extensive research on grazing for vegetation management and weed control over the years, the feasibility and cost/benefit of grazing in the highway right of way has not been well documented. To help do this, WSDOT is conducting field trials using goats in three different vegetation management situations and terrains around the state.

The study is testing goats for routine mowing of unwanted weeds and brush around fenced stormwater ponds at several sites near Vancouver, using goats donated by a WSDOT maintenance employee. The trials also will study water quality impacts in areas with standing water and potential outflow.

Goats clear grass and weeds near Olympia area interchange. Photo: Washington State DOT Flickr Photostream

A second site in Spokane is studying the use of goats to prevent or delay seed production in a noxious weed infestation along US 395.

Finally, the department is using goats to clear unwanted vegetation from a former homeless camp along Interstate 5 in Olympia. 

As part of the study, WSDOT will document all costs associated with labor, feed, transportation, and fencing of the goats and will issue its findings in a research report, expected in fall of 2015.

The initial finding of the research is that in general, goats have a very limited application for roadsides, according to Willard. One type of situation that may prove effective is in controlling vegetation within fenced stormwater ponds, where the animals don’t require constant supervision and don’t present a potential distraction to drivers.

For more information, link to WSDOT’s Vegetation Management Program and Pollinators and the Roadside webpages or contact Ray Willard at WillarR@wsdot.wa.gov.

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AASHTO's Compendium of Environmental Stewardship Practices, Policies, and Procedures

This compendium provides models of many successful approaches.  Of particular use are the following Chapters: Chapter 3: Designing for Environmental Stewardship in Construction & Maintenance, Chapter 4: Construction Practices for Environmental Stewardship, Chapter 9: Roadside Vegetation Management.

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FHWA Compilations

Greener Roadsides

Many successful practices are documented in Greener Roadsides, a publication produced by the Federal Highway Administration.

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