Off the beaten path: a park's accessible trails take a path outside their original design.

For Prairie Creek Redwoods State Park, building trails that are accessible to hikers with disabilities was just the start of its history of easily traversable pathways. An initial design eight years ago has paved the way for the future of the park's trails and set an example for other parks.

Working with the non-profit organization Whole Access, the North Coast Redwoods District of the California Department of Parks and Recreation sponsored a multi-disciplinary Trail Design Charette, a brainstorming group, in Eureka, Calif., in 1998. The five-day synergistic problem-solving session focused on developing a process for evaluating and designing recreational trails to determine the greatest amount of accessibility without adversely affecting the natural and cultural resources of the land.

The extensive review of two trails led participants to a functional design plan. The initial section of Prairie Creek Trail was completed in 1999 and the majority of Foothill Trail was finished in 2003, for a total of about two miles of accessible trails in the park. The redesign of these two trails earned the Trail Design Charette the 2002 Harvey Bell Memorial Award, given by the Western Trail-builders Association.

But the completion of the group's design wasn't enough for Prairie Creek Redwoods State Park. Since then, an additional seven miles of trails have been made accessible, for a total of nine accessible miles throughout the park.

The park's management learned quickly that trail accessibility is an ongoing process, involving adaptive management and subtle refinement rather than major changes.

Karl Knapp, a trail construction specialist and charette team member, says that the park's updated trail design was important to the future of accessible trails because of its intersection with the U.S. Access Board-proposed trail guidelines. "The charette was actually taking place during the timeframe that the committee was drafting the proposed guidelines."

Knapp says that continuing trail accessibility programs, in the manner that Prairie Creek did, makes an impact on the community. "In California state parks, there is a desire to improve as many trails to meet the proposed guidelines as possible," he says. "I think getting as many different environments out there that are doing their best to meet the proposed guidelines and seeing how it works is important."

John McGovern, executive director of the Northern Suburban Special Recreation Association and Access Board member explains that the guideline proposal process is still in the works. "In 1997, the Access Board appointed a federal advisory committee to address outdoor developed recreation areas. The committee met through mid- to fall of 1999, and our job on the committee was to reach consensus and pass it on to the board about how to make trails, beaches, picnic areas, campsites and camping amenities accessible," McGovern explains. "I think it's safe to say that we did not reach consensus. As a result, we turned a final report into the access board that all of us did not agree with. That's part of the reason why the Access Board hasn't issued this either as an advanced notice of proposed rulemaking or as a notice of proposed rulemaking."

McGovern says that because there are no final guidelines, it is up to individual agencies to determine a "best practices" plan for their situation. This can be achieved by looking not only at the proposed guidelines, but also examples of accessible designs other parks have implemented.

The trails in Prairie Creek Redwoods State Park are a trend-setting example. The advantages of the park extend beyond the benefits to park visitors with disabilities. Of the 75 miles of trails in the park, park officials observe that the nine miles of accessible trails are the most heavily used. But users who haven't done their research won't know that the trails were specially designed by a council of accessibility specialists--part of the trails' dual purpose is to look as natural as their surroundings.

That natural look masks the extensive work that went into their construction. While an example of good design, the trails are also a model for the challenges that accessible designs can present. The two trails first tackled by the charette team were totally inaccessible at the beginning of the process with numerous maintenance and resource degradation issues.

"The most difficult part of the design was the fact that you were dealing with extensive reroutes and an environment that was moist and wet," Knapp says.

Prairie Creek Trail closely followed a stream and meandered through a broad and heavily forested stream valley. The trail was flat in some places and as steep as a 36 percent grade in others. These grades, as well as steps and bridges with step approaches presented obstacles to accessibility. Natural factors, such as roots protruding into the trail bed and water-saturated tread surfaces also created obstacles and barriers.

Foothill Trail was located on a steep hill slope and ran through an old-growth redwood forest, winding around both standing and fallen giant trees.

Grades as steep as 59 percent, severe cross slopes, narrow tread widths, drop-offs, steps and bridges with step approaches presented significant obstacles to accessibility. Foothill Trail was also plagued with similar root problems and wet surfaces.

The trails' reconstruction meant attention to detail, most of which involved realigning the trail so that the grades were accessible to visitors that are disabled. And rather than taking away from the nature of the park, designers made the trails' surfaces a mix of shale and native soils.

The charette helped identify the commonalties between good trail design and accessible design. It also showed that the conflicts between those two disciplines could be solved or mitigated with simple design and construction solutions that already exist and are commonly used by trail designers and builders. Finally, it defined a process for re-designing existing trails or designing new trails to maximize accessibility, protect resources and provide sustainable trails. This process can be applied universally to all trails regardless of their location or conditions.

Through the charette process, implementing the extensive construction of the trails and continuing the trail efforts beyond the initial concept has made the park a model of accessibility success. But the park staff looks beyond its past successes to the future. After all, they have nine miles down and 64 to go.

Commonalties Between Accessibility, Resource Protection & Sustainable Trail Design

1. Curvilinear alignment produces a good sustainable trail and more moderate linear grades.

2. Moderate linear grades have less erosion, greater sustainability and higher access potential.

3. Firm, stable and uniform tread surfaces promote good sheet drainage, reduce tread deformation, soil saturation and improve access.

4. Tread surfaces with a good coefficient of friction provide a safer and more pleasurable hiking experience and improve accessibility.

Solutions and/or Mitigations to Maximize Resource Protection and Sustainable Trails

1. Linear trail grades are kept moderate--between five and eight percent, with short runs up to 10 percent.

2. Layout of trail maximizes side hill construction to provide a fuller native trail bench for better durability, drainage and sustainability.

3. Trails located on flat terrain are turn-piked to provide drainage and protect tree roots.

4. Trail structures such as retaining walls, bridges and drain lenses are kept to a minimum and are used to protect resources and maintain good linear grades.

5. Trail cross slope is kept at five percent but may be up to eight percent depending on the linear grade, tread width and type of tread surface.

6. Edge protection is provided when conditions warrant it, and is installed in a manner to facilitate sheet flow. Native vegetation and natural features such as rocks and logs can serve as edge protection.

7. Trail tread widths are designed to be a minimum of 36 inches and are widened only to mitigate conditions affecting accessibility.

8. Tread surfaces need only to be firm, stable and have a good coefficient of friction.

9. Mobility assistive devices that have a greater capability of traversing recreation trails need to be made available.

Solutions and/or Mitigation to Maximize Accessibility

1. Increasing the tread width and improving the coefficient of friction of the tread surface to mitigate steeper linear grades.

2. Widening the tread width, improving the tread surface and or providing edge protection to mitigate combinations of steeper linear grades, higher cross slopes and changes of directions.

3. Widening the tread width and or installing edge protection mitigate locations with a steep drop-off.

4. Trail tread surfaces are well-shaped, compacted and constructed on fuller benches to provide better firmness and stability.

5. Native soils are augmented with crushed shale rock when additional strength and firmness is required.

6. Tread surfaces are constructed to be uniform but have enough roughness and texture to provide a good coefficient of friction.

7. Trail structures that create barriers are eliminated such as steps, water bars and open culverts.

8. Trail tread widths are designed to be a minimum of 36 inches.

9. Tree roots protruding into the trail tread are covered with native soils or a combination of crushed shale rock and native soil.

10. Rocks protruding into the trail tread are removed or covered with native soils or crushed shale rock.

11. Vertical obstructions are either removed or mitigated by installing features that warn trail users that are visually impaired.

Web extra: Read about the problems that can exist when trying to manage resource protection, trail sustainability and accessibility. www.nrpa.org/p&r