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Chapter 10
Roadside Management and Maintenance: Beyond Vegetation

Highway agencies manage over six million hectares (17 million acres) of land in the U.S., approximately one percent of states with more dense road networks. [N] Due to the tendency of the highway system to follow streams, coastlines and other natural landscape features, this land is often located within, over, and/or adjacent to many environmentally sensitive resources.

All ROWs are managed with the general goal of providing for safe and reliable transport. In most all ROW scenarios, active management is needed to create specific vegetation and related environmental conditions. [N] Roadside management objectives vary with the zone that is being addressed. Typically the gravel shoulders of roads are maintained as a vegetation-free area, to allow surface water drainage off the pavement and into the drainage ways. Off the shoulder, an operation zone of grass or small trees and shrubs is maintained through mowing to allow for visibility of signs and traffic at interchanges and curves. Large trees are removed for safety in case vehicles accidentally leave the road. Herbicides are used very selectively for control of noxious weeds and sometimes for brush control. A wider buffer zone beyond that area is commonly maintained in natural or native, low-maintenance vegetation.

Common objectives for management of the ROW include:

  • Managing the immediate shoulder for use as a recontrol zone for errant vehicles and to inhibit weeds from growing into the pavement.
  • Preserving sight distances for reading signs and for cornering.
  • Offering space for utilities.
  • Screening on-coming traffic on divided highways.
  • Maintaining slope stability, encouraging drainage of water off the roadway, protecting water quality, protecting habitat for wildlife and preserving or restoring native plant communities.
  • Maintaining open space, green corridors, or a refuge for biodiversity. 
  • Protecting roadside areas against infestation and spread of noxious weeds.
  • Keeping vegetation back from the edge of the road to improve visibility of wildlife and reduce chance of road kill.
  • Providing on-site area for wetland mitigation.

This chapter focuses on non-vegetative environmental stewardship practices for management of the ROW.

10.1. Environmental Enhancement Practices and Partnership Efforts

10.1.1 Water Quality Retrofit Programs

Most DOTs have developed or utilize existing design manuals for runoff control and stormwater quality. Increasingly, DOTs have to decide where stormwater quality retrofits may be sufficiently valuable to implement, and in what order these investments should be prioritized. In addition to extensive design guidance available in both manual and on-line formats, a number of BMP selection and evaluation systems are emerging. NCHRP 25-20(01) " Evaluation of Best Management Practices for Highway Runoff Control" is designing a BMP effectiveness and evaluation system that will be available in late 2004.

MDSHA's Water Quality Improvement and Retrofit Program

MDSHA's NPDES program was implemented as part of mandated EPA regulations; however, the program's many activities have exceeded the regulatory requirements due to MDSHA's environmental policy to go beyond the basics and explore new ways to implement environmental stewardship in the context of the sensitive Chesapeake Bay Watershed. The agency leadership and staff have become very active in advancing the cause of the environmental protection through technology development and enhancement. Funds have been provided and partnerships have been forged to leverage the state dollars and maximize the best management practices (BMPs) at an unprecedented level.

As part of the agency's environmental quality improvement efforts, MDSHA has implemented a very structured improvement program for the 1,500 stormwater management facilities owned by MDSHA, with inspection teams of trained staff who identify further environmental improvements that can be made. MDSHA has complimented this work by mapping the entire state for opportunities for retrofitting BMPs, for pollution prevention and stream restoration beyond requirements, and for development of a plan for systematic implementation of those improvements.

The grade-based rating system for stormwater management facilities include an inventory, database, and photo record of all facilities statewide and their maintenance status. Under the rating system, those graded A or B are considered functionally adequate. As of late 2003, between 73 and 75 percent of MDSHA stormwater were functionally adequate (A=everything fine, working fine, no maintenance required, B= minor maintenance, need mowing or trash removal), leaving approximately 25 percent needing maintenance or retrofitting to achieve functional adequacy. MDSHA aims to have 80 percent or more of their stormwater management facilities rated functionally adequate by 2006, and 95 percent of facilities by 2010.

With continuous improvement as an inherent strategy, the NPDES team has accomplished many major goals since its inception in 1999:

  • Developed NPDES Strategic and Timeline Plan to guide the overall implementation effort.
  • Developed several pilot projects to streamline the integration of technology into the field data collection and analysis process.
  • Established field inspection protocols and tools for data collection, including a Standard Procedures Manual to streamline the database development, inspection protocols, and training program for inspecting stormwater management facilities.
  • Established auxiliary programs and management structures to support the goals of the NPDES program.
  • Partnered with several local jurisdictions in their watershed assessments and restoration efforts - MDSHA is now partnering on eight different watershed improvement plans
  • Constructed multitude of stormwater retrofit and enhancement projects throughout Maryland with immediate benefits to the environment. Many more are underway.
  • Developed many cutting edge technologies for stormwater management such as Low Impact Development (LID) for highway environment and out-of-kind stormwater mitigation such as stream restoration.
  • Developed the nation's first and only Visual and Environmental Quality Guidelines for Stormwater Management Facilities. Implementation of the draft guidelines already resulted in facilities that benefited from this context-sensitive approach.
  • Developed a Geographic Information System (GIS) for drainage infrastructure.
  • Developed Geographic Information Management System (GIMS) for systematically inspecting and maintaining the performance of stormwater management facilities.
  • Initiated efforts to develop new state-of-the-art BMP remediation technology.
  • Developed a work delivery system using operating and capital programs.
  • Developed a flow chart for SWM facility remediation action along with cash flow estimates.
  • Developed a budgetary cash-flow estimation system with the help of pilot projects.
  • Developed training for designers on stormwater management based on data found in the inspection program.
  • Performed Discharge Characterization of stormwater to analyze quality of highway runoff.
  • Prepared a report on MDSHA's on-going Public Education and Outreach Programs and initiated new efforts (Environmental Responsibility Booklet, Cable-broadcast video, informational presentations).
  • Established Pollution Prevention Teams at all 35 MDSHA Maintenance Facilities to implement the Stormwater Pollution Prevention Plan in an environmentally responsible manner - includes pollution prevention training to personnel.
  • Customized pollution prevention plans and strategic retrofit plans for all MDSHA maintenance facilities to systematically upgrade them to perform at an environmentally acceptable level.
  • Initiated technology transfer and guidance to other Maryland Department of Transportation (MDOT) modals.

The Managing for Results (MFR) portion of MDSHA's business and stewardship plan is being used to measure the progress and success of the NPDES program and define timelines and milestones for the numerous elements of the program. Using the MFR approach, progress is measured every month for each of the major elements, and every six months for all the elements of the program. An example of this is the tracking of the required number of source identification efforts that needed to be completed: The strategic plan as well as the MFR goals called for measurable completion of work in specified counties by a prescribed date. Another example is the stormwater management retrofits that needed to be completed by December 2003. The retrofit completion progress was tracked every month and new strategies were developed continuously. As a result, this requirement was exceeded by 300 percent. Individual projects, such as watershed retrofits, stormwater improvements and watershed partnerships that are generated as a part of the program are managed using MS Project and milestone reviews.

For maintenance facilities, the discharge sampling of the outfalls is a direct method for measurement of success, which is defined based on state and federal requirements. As a stewardship measure, MDSHA tracks implementation of strategic upgrades to the facilities identified during the pollution prevention plan development and needed changes in systems identified by the independent inspection program.

Charts are developed for all the major programs to visually demonstrate successes and progress. Once a year, an annual report summarizing all the activities, including compliance with the NPDES program is prepared and submitted for review to the Maryland Department of the Environment (MDE). So far, every report was thoroughly reviewed and approved by MDE, which means MDSHA remains in compliance and is actually being commended for showing stewardship by exceeding the permit requirements. A copy of the recent annual report is attached.

Outfall Categorization and Improvement at Florida and Washington State DOTs

In the late 1990s WSDOT and FDOT developed systems for categorizing and improving outfalls. [N] In the case of WSDOT, assessing which projects provide the best return on investment in terms of environmental effectiveness and pollution reduction. WSDOT's system included a condition indexing methodology and support program that enables users to quickly evaluate and compare projects and generate benefit-cost ratios for projects. [N]

Further information on outfall improvements is available in descriptions of WSDOT's program, as well as that of Oregon DOT, in section 3.5, Culverts and Fish Passage.


10.1.2 Wetland Enhancement
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PennDOT Staff Partner to Enhance Local Wetlands

PennDOT construction and maintenance workers are involved in a pilot program to improve eight wetlands in the state's District 9 territory. In 1995, the six-county region was chosen as the lead for PennDOT's wetland banking program to help save the state's natural resources. Working with several organizations - including EPA, the Army Corps of Engineers and FHWA - PennDOT and the agencies are identifying wetland enhancement sites, some of which may serve as compensation for past and future wetland impacts. The largest restoration area thus far is a 40-acre site prepared by PennDOT staff. In the summer of 2000, PennDOT workers, with assistance from the state's game commission, removed all of the drains and constructed berms to hold in water. Workers planted trees, warm-season grasses and thick, shoulder-high shrubs and brush to attract wildlife. The game commission donated bird, duck and bat "boxes" (houses). Ducks, pheasants, shorebirds, turtles, deer, muskrats and other species are flourishing in restoration area and predators such as coyotes, foxes, and an assortment of snakes have returned. The project cost less than $3,500 per acre to complete; the agency estimated the project would have cost an extra $1.4 million if a contractor had been assigned to do the work, as $100,000 per acre is a going price. Schools became involved in the planting, saving taxpayer dollars, and students return to the area on field trips. [N]


10.1.3 Terrestrial Habitat Enhancement
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Native habitats and populations of native cavity nesting birds have been in long-term decline across the country. Loss of suitable nesting sites and competition from non-native birds are the major factors in these population declines. Some DOTs are taking this problem on by trying to enhance the habitat under DOT ownership. These extend from large-scale efforts to help state resource agencies and the governor's office implement greenway plans in Maryland, Florida, and Pennsylvania, to DOTs placing nesting platforms for ospreys in the right-of-way.

NYSDOT's Guidance for Placing Nest Boxes in ROW

NYSDOT has estimated that the agency owns and maintains approximately one percent of the state's land area and thus that the DOT has the potential to enhance nesting opportunities for native cavity nesting birds through well-considered design and placement of nest boxes. Nest boxes must be of the appropriate type, placed in suitable habitat and monitored on a regular basis during the nesting season, as failure to consider these factors can result in inadvertently enhancing nesting opportunities for non-native birds and further erosion of the ecological niches of native species. NYSDOT developed a bulletin on Nest Boxes for Native Cavity Nesting Birds that provides basic information and recommendations regarding the proper use of nest boxes on and adjacent to NYSDOT property. The guidance provides Attachment A: Reference and Attachment B: Internet Sites for Nesting Box Designs.

NYSDOT Region 6 environmental and maintenance staff developed a program that involves a federally licensed bird bander and volunteers to manage a roadside trail of 15 artificial nest boxes. NYSDOT maintenance workers constructed nest boxes for the American Kestrel and installed them on the support posts of existing large expressway signs. Environmental staff and volunteers regularly monitor the boxes and NYSDEC biologists band the hatchling kestrels to collect scientific information.

DOT Bat Boxes

Bat roost enhancement projects for roadways can often be conducted onsite. Commercially produced bat houses are available that can accommodate up to tens of thousands of bats. Retrofitting options for bridges are discussed in section 7.2, Avoiding and Minimizing Impacts to Fish and Wildlife and Enhancing Habitat

Best practices for constructing or buying bat houses are outlined below, excerpted and summarized from The Bat House Builder's Handbook, based on 12 years of bat house research conducted across the U.S, Canada, and the Caribbean. [N]

  • Design - All bat houses should be at least 2 feet tall, have chambers at least 20 inches tall and 14 inches wide, and have a landing area extending below the entrance at least 3 to 6 inches (some houses feature recessed partitions that offer landing space inside). Taller and wider houses are even better. Rocket boxes should be at least 3 feet tall and have at least 12 inches of linear roost space. Most bat houses have one to four roosting chambers-the more the better. Roost partitions should be carefully spaced 3/4 to 1 inch apart. All partitions and landing areas should be roughened. Wood surfaces can be scratched or grooved horizontally, at roughly 1/4- to 1/2-inch intervals, or covered with durable square, plastic mesh (1/8 or 1/4 inch mesh). Include vents approximately 6 inches from the bottom of all houses 24 to 32 inches tall where average July high temperatures are 85º F or above. Front vents are as long as a house is wide, side vents 6 inches tall by 1/2 inch wide. Houses 36 inches tall or taller should have vents approximately 10 to 12 inches from the bottom.
  • Construction - For wooden houses, a combination of exterior plywood (ACX, BCX, or T1-11 grade) and cedar is best. Plywood for bat house exteriors should be ½-inch thick or greater and have at least four plies. Do not use pressure-treated wood. Any screws, hardware or staples used must be exterior grade (galvanized, coated, stainless, etc). To increase longevity, use screws rather than nails. Caulk all seams, especially around the roof. Alternative materials, such as plastic or fiber-cement board, may last longer and require less maintenance.
  • Wood Treatment - For the exterior, apply three coats of exterior grade, water-based paint or stain. Available observations suggest that color should be black where average high temperatures in July are less than 85º F, dark colors (such as dark brown or dark gray) where they are 85 to 95° F, medium colors where they are 95 to 100º F and white or light colors where they exceed 100º F. Much depends upon amount of sun exposure; adjust to darker colors for less sun. For the interior, use two coats dark, exterior grade, water-based stain. Apply stain after creating scratches or grooves or prior to stapling plastic mesh. Paint fills grooves, making them unusable. Darker colored bat houses are recommended in northern climes.
  • Sun Exposure - Houses where high temperatures in July average 80º F or less, should receive at least 10 hours of sun; more is better. At least six hours of direct daily sun are recommended for all bat houses where daily high temperatures in July average less than 100º F. Full, all-day sun is often successful in all but the hottest climates. To create favorable conditions for maternity colonies in summer, internal bat house temperatures should stay between 80º F and 100º F as long as possible.
  • Habitat - Most nursery colonies of bats choose roosts within 1/4 mile of water, preferably a stream, river or lake. Greatest bat house success has been achieved in areas of diverse habitat, especially where there is a mixture of varied agricultural use and natural vegetation. Bat houses are most likely to succeed in regions where bats are already attempting to live in buildings.
  • Mounting - Bat houses should be mounted on buildings or poles. Houses mounted on trees or metal sidings are seldom used. Wooden, brick, or stone buildings with proper solar exposure are excellent choices, and locations under the eaves often are successful. Single-chamber houses work best when mounted on buildings. Mounting two bat houses back to back on poles is ideal (face one house north, the other south). Place houses 3/4 inch apart and cover both with a galvanized metal roof to protect the center roosting space from rain. All bat houses should be mounted at least 12 feet above ground; 15 to 20 feet is better. Bat houses should not be lit by bright lights.
  • Protection from Predators - Houses mounted on sides of buildings or on metal poles provide the best protection from predators. Metal predator guards may be helpful, especially on wooden poles. Bat houses may be found more quickly if located along forest or water edges where bats tend to fly; however, they should be placed at least 20 to 25 feet from the nearest tree branches, wires or other potential perches for aerial predators.
  • Avoiding Use by Other Species and Waste Accumulation - Wasps can be a problem before bats fully occupy a house. Use of 3/4-inch roosting spaces reduces wasp use. If nests accumulate, they should be removed in late winter or early spring before either wasps or bats return. Open-bottom houses greatly reduce problems with birds, mice, squirrels or parasites. Furthermore, guano does not accumulate inside.
  • Timing - Bat houses can be installed at any time of the year, but are more likely to be used during their first summer if installed before the bats return in spring. When using bat houses in conjunction with excluding a colony from a building, install the bat houses at least two to six weeks before the actual eviction, if possible.
  • Importance of Local Experimentation - It is best to test for local needs before putting up more than three to six houses, especially comparing those of different darkness and sun exposure.

DOTs have contributed to bat conservation and recovery through assisting mine gating efforts. Sealing abandoned mines without first evaluating their importance to bats is one of greatest threats to North American bat populations, which use caves as hibernacula.

Bridge Related Enhancements

Techniques to minimize construction and maintenance impacts on bats are discussed at length in Chapter 7 on Practices in Bridge Construction and Maintenance. Impacts to birds and practices to benefit birds are discussed in that section as well, to a lesser extent. Practices that benefit ground-nesting birds are discussed in Chapter 9, in particular, those related to Reduced Mowing in section 9.5.

Reduced Mowing at DOTs to Conserve Resources, Bird Habitat, and Native Species

As part of their Integrated Roadside Vegetation Management or other conservation plans Colorado DOT, Iowa DOT, Mn/DOT, WisDOT, NYSDOT, and Utah DOT have implemented mowing reductions to conserve resources and benefit native species. In most cases, these programs preserve habitat for ground-nesting birds and other native species by limiting mowing to one mower width along the roadway. For more information see Chapter 9 of this report.

Iowa DOT Roadside Native Species Restoration Program in Maintenance

While many state DOTs have begun to mandate use of native species when revegetating construction sites, Iowa DOT has extended their landmark IRVM program to revegetate approximately 2,200 acres annually of targeted roadside areas not connected to any construction projects. Another 3,200 acres of roadside on construction sites are seeded annually with native grasses and forbs. The state's transportation commission actively supports the program.


10.1.4 Identifying and Implementing Aquatic Connectivity (Fish Passage) Improvements
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Oregon DOT Culvert Retrofit and Replacement Program Agreement

In 2001, the Oregon Department of Transportation (ODOT) and the state Department of Fish and Wildlife (ODFW) signed a Memorandum of Understanding (MOU) that repairing or modifying ODOT-maintained culverts is a priority for the agencies that will take decades to resolve. The ODFW completed culvert inventories for the entire state of Oregon in 1999 and found that 96 percent of the barriers identified were culverts associated with road crossings. The project also identified high priority culverts for fish passage remediation.

ODOT has an ongoing program of culvert installation and maintenance, with the goal of making all ODOT culverts passable to fish. After research monitoring results demonstrated the effectiveness of baffle and weir designs in culverts, ODOT modified their culvert replacement programs to use these designs, significantly reducing the cost of improving fish passage at ODOT culverts. The designs improve fish passage by slowing water velocity and raising stream elevations to reduce entry jump heights or backwater culvert outlets. Use of retrofit designs are allowing culverts that are otherwise in good physical condition to be retrofitted until their service integrity is compromised, at which time they will be replaced with designs that more fully meet fish passage criteria and standards. Use of retrofits allows many more culverts to be remediated each year, increasing the scope and pace of ODOT's contribution to salmon recovery in Oregon. The baffle and weir retrofits provide ODOT an alternative to fish ladders, which have become increasingly problematic for ODOT from a maintenance standpoint.

According to the MOU, ODOT will continue internal education regarding the needs and requirement of fish passage and prioritize its resources and culvert modification needs on an annual basis, demonstrating good faith in addressing culvert passage problems. On replacement culvert projects, ODOT will strive to simulate a natural stream and will determine if changes in culverts result in flows detrimental to fish passage. ODFW is supporting ODOT's efforts by providing the master inventory of culverts that do not provide adequate passage, along with technical assistance on educational activities, design, and construction techniques.


10.1.5 Installation/Improvement of Public Fishing Access
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NYSDOT Public Access Enhancement and Partnership

NYSDOT has been exploring and extending the highway system's larger role of connecting people and places of interest. Looking out for these needs, the NYSDOT Niagara County maintenance staff took the lead in forming a partnership with local business, the NYS Office of Parks Recreation and Historic Preservation and the New York State Department of Environment Control, to provide a public fishing access site and picnic area at a popular salmon and trout stream - Keg Creek. Anglers formerly parked haphazardly along the state highway and traversed a very steep, slippery and dangerous ravine to fish for Lake Ontario's world famous migrating trout and salmon. This created a safety problem for passing motorists and for the anglers themselves. NYSDOT maintenance crews designed and constructed a paved parking area, a series of wooden stairs and a picnic area with lumber donated by a local company and tables donated by the State Parks Department. [N]


10.1.6 Extending Highway Maintenance Activities to Bicycle Trails
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Under the "Livable Delaware" Plan, Delaware DOT is extending Highway Operations Maintenance Policy to care for an increasing number of bicycle paths and sidewalks. Until the recent past, there have been relatively few bicycle paths and sidewalks within the state's right-of-way. Public input was relatively minor, requests for service were handled individually, and actions were very specific to satisfy only the scope of the complaint being responded to.

DelDOT assessed the current situation and is implementing the following practices for bicycle paths: [N]

  • For those bicycle paths which have been, or will be created within the paved surface of the roadway, and designated by paint striping, cleaning and repair of these facilities will be accomplished within the existing established procedures and policies governing highway sweeping and pot hole repair.
  • Develop policy guiding frequency of cleaning and standards defining an acceptable level of maintenance where bicycle paths are constructed as separate, stand-alone facilities.
  • Obtain specialized equipment not currently in the Department's inventory or contracted services to properly maintain separate paths. Existing equipment is designed for roadway service and is too large and heavy to be utilized on stand-alone bikeways without damaging the physical structure of the path.

DelDOT noted that sidewalks located within the state's right-of-way along maintenance numbered roadways outside of municipal boundaries have long been given minimal attention, and that no standards or policies define frequency of cleaning or serviceability. Where failures occur, they are not addressed unless significant public input is received. DelDOT has formed a committee to develop overall maintenance policies for sidewalks outside of subdivisions in general.

The committees for bicycle paths and sidewalks were appointed by the Directors of Highway Operations, Pre-Construction, and Planning since planning and design considerations must be considered in development of an adequate and rational maintenance policy; e.g., where a sidewalk and/or bicycle path is placed relative to the roadway will have significant impact on the ease of cleaning and maintaining the facility, requiring that these long-term activities be fully considered in the project development phase. The Delaware Bicycle Council, County governments, and numerous municipalities are feeding into the process.


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Continue to Section 10.2 »
Table of Contents
Chapter 10
Roadside Management and Maintenance: Beyond Vegetation
10.1 Environmental Enhancement Practices and Partnership Efforts
10.2 Protection of Historic and Other Cultural Resources
10.3 Maintenance in Wetlands
10.4 Maintenance Near Waterbodies
10.5 Maintenance of Structures for Wildlife
10.6 Maintenance of Stormwater Facilities
10.7 Maintenance of Roadside Public Facilities
10.8 Management of Portable Sanitary/Septic Waste Systems
10.9 Maintenance of Shoulders and Roadway Appurtenances
10.10 Sweeping and Vacuuming of Roads, Decks, Water Quality Facilities, and Bridge Scuppers
10.11 Maintenance Stewardship Practices for Slopes, Drainage Ditches, Swales, and Diversions
10.12 Erosion and Sediment Control in Maintenance
10.13 Recycling in Roadside Maintenance Operations
10.14 Preserving Air Quality in Maintenance and Operations
10.15 Painting Operation Stormwater BMPs
10.16 Road Waste Management
10.17 Stockpiling, Spoil Disposal or Placement of Inert Fill
10.18 Maintenance of Soils
10.19 Emergency Actions
10.20 Field Review of Roadside Maintenance Operations
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