Safe Trestles
A Search for Balance
Introduction
In thinking about the future of the Trestles, there are many legitimate, but competing, issues to consider and choices to make. For starters, there are the issues of preservation, access, safety, enhancement and economy. Within the broad category of preservation though, there are many variations -- preservation as it existed before the arrival of Europeans? As it was a hundred years ago? As it is today? And when considering access, is it access for the hardy? For the handicapped? For the multitudes?
In our design, we have attempted to understand these concerns and to find an appropriate balance among them, while knowing that no specific choice we have made will satisfy everyone. We do hope, however, that everyone will find something in the design to appreciate and perhaps even to inspire.
Response to the Design Goals
1) Provide safe access between the drop-off point, the railroad, and the beach.
We propose a low profile, accessible, solution: a path making a gradual descent from the Old Highway, closely following the contours of the land, and crossing the railroad track at grade level. Finally, a raised boardwalk spans the wetlands to arrive at Lowers.
2) Restore and protect the coastal wetlands that have been damaged by foot traffic.
The wetlands lie squarely across any reasonably direct route from the old highway to Lowers. A path that addresses this issue by routing traffic around the wetlands would need to ensure that visitors stay on the path, especially at the railroad crossing. Although this might be done with an elevated railroad crossing or the construction of barriers to the wetlands, we rejected these solutions as unjustifiably expensive and/or visually obtrusive to Trestles' natural setting.
Instead, our approach is simply to make staying on the path more convenient than hiking through the wetlands. We have moved the trail head at the Old Highway to the northwest, which both lowers the starting elevation and makes the entry point more convenient for the majority of visitors, who come from that direction. The path follows the natural contours of the land as it gradually descends through the coastal sage scrub (the most robust of the vegetation zones) for most of the descent. When it gets to the wetlands, there is a direct path to Lowers over a raised boardwalk. Between the railroad and the beach, we follow the route that people have already voted for with their feet, as evidenced by the shortcuts created in the dry season.
The use of raised boardwalks over wetlands has a long history and has been shown to have no negative long term impact on the vegetation or fauna. The boardwalk can be constructed without heavy equipment compacting the wetlands soil, by advancing the equipment along the partially built boardwalk as it is extended.
This new path, without modifications, would open up a new potential threat to the wetlands. Not everyone coming down the path wants to go to Lowers; Middles is also popular. The proposed path crosses the railroad track 350 feet west of the current crossing. Reaching the railroad crossing and turning east, people going to Middles might be tempted to create new shortcuts through the wetlands, just as they previously did when going to Lowers.
We address this potential problem by providing a short connection between the new and old paths just north of the railroad tracks. If someone is heading for Middles and isn't limited by accessibility concerns, they will naturally take the fork to the old path because it goes in the direction they are going. When the old path reaches the railroad track, it is far enough east to not tempt people to cut through the eastern stretch of the wetlands. This can be seen by the fact that historically, no dry-season shortcuts to Middles have been created.
3) Provide opportunities for viewpoints and education.
The Trestles is an astounding place. It provides its own views. The route we have chosen has a shifting panoramic view as it descends, but there is no need to add architectural structures specifically to create view points.
What we have done is provide observation platforms at several points along to way that double as rest areas for those with disabilities and as places for educational opportunities.
We have not, in general, attempted to select the educational content. However, we do think our design creates an unique opportunity to raise public awareness of complex ecological issues. Our design pictures the use of bamboo in a non-structural role. We propose the use of a locally growing bamboo-like plant, Arundo Donax which is native to the Mediterranean, as a substitute for some of the bamboo.
In many ways similar to the Eucalyptus tree from Australia, Arundo Donax was brought into California in the nineteenth century for its perceived economic value, but has since become an exotic weed that threatens the native flora and fauna. Both have been removed (at great expense) from the Trestles Wetlands Natural preserve, but this has been a controversial action. The incorporation of Arundo Donax at one of the educational areas would serve as an introduction to an awareness-raising presentation of the variety of ecological and political issues that need to be considered when transporting biological material from one area of the world to another.
4) Provide solutions for accessibility, including ADA compliant facilities.
Accessibility is not an issue only for the handicapped; access is needed for everyone. The accessibility needs of a bicyclist towing a surfboard on a trailer are different from those of either a pedestrian or a wheelchair user.
The two accessibility issues that most affected our overall design are the difference in elevation between the Old Highway and the beach, and the need accommodate a large variety of transportation modes. We considered many variations of mechanized lifts, but in the end rejected them on the basis of the expense of construction, operation and maintenance. We also considered various forms of switchbacks, but rejected those because of the wide tuning radius needed by a bicyclist towing a surfboard trailer. In the end, we settled on a path that descends at a rate never exceeding a 20:1 (5%) slope and without any sharp turns. This required that we move the trail head to the northwest of its current location, which both decreased the elevation and lengthened the horizontal distance. This is a robust approach to keeping the slope at 5%. Although we worked from the USGS topographic data, if a more accurate survey shows that the route needs adjustment to maintain the desired slope, the trail head can be moved farther down the Old Highway.
As for recognizing the differing needs of pedestrians, wheelchair users, bicyclists carrying a surfboard under the arm, bicyclists towing a surfboard on a trailer, etc., we felt a need to widen the width of the path well beyond the four feet minimum specified in the competition design rules. The US Department of Transportation's accessibility guidelines Designing Sidewalks and Trails for Access says that a shared-use path, as this is, should be at least 10 feet wide. Given that a very common mode of transportation is a bicyclist with surfboard, often carried or mounted on the side of the bicycle, there is a good argument for making the path even wider than 10 feet. But that would increase both construction costs and visual impact, and we settled on 10 feet.
Numerous other accessibility issues guided the more detailed design, such as
• Level rest stops
• 42" edge protection
• Slip resistant surfaces
• Cross-wise planks
• Signage for accessibility
• Familiar railroad crossing gates
• Accessible restroom and water fountains
Cost effectiveness
We accomplish this through the use of readily available materials, and straightforward construction techniques, including standard lumber dimensions, simple shading devises, and more.
Other Objectives
• Incorporate the pilings throughout the design, to echo the Trestles' history.
• Keep the solution as low to the earth and unobtrusive as possible, in an effort to not detract from the natural beauty of the area.
• Veer the path back and forth slightly, to add to the feeling of adventure/discovery/exploration many of the surfers have indicated is part of the Trestles' intrigue.
Our Process
To facilitate this effort in design collaboration, we developed a grassroots plugin for a multi-user, online, virtual environment. With this technology, we were able to focus a very diverse range of ideas into a naturally evolving process ranging from comprehensive text-based research to 2D plan diagrams and on into immersive 3D virtual models designed and built on a replica of the project site.
The virtual replica we have developed will not disappear after this competition is complete, but will live on as an evolving virtual model of the real life site, echoing each new development and opportunity as the project comes to life. This mirror rendition of the project site will enable many people from around California and the world to experience the local site and conditions as it evolves, further expanding the outreach, awareness and support for this project. In addition to the virtual counterpart, we have also introduced a web-based 2D portal that communicates with the virtual model. In this way, those who cannot or do not care to access Second Life, will still be able to join the team and lend their specific knowledge and support.
We believe that our design should be reviewed and further refined with direct input from all the passionate stakeholders personally invested in this project. Our entire design process has been collaborative and fluid, and we have no illusions that we have reached the optimal trade-off among the many practical and aesthetic considerations. We can only achieve excellence by incorporating more local knowledge and experience into the design.
Concluding Remarks
This submission is the end result of a group of individuals collaborating using open tools and open methods. With the exception of a visit to the site, the entire design process was conducted over the Internet. The group is open to anyone who believes in developing the collaborative process.
Our group is diverse and includes people from many professions and walks of life. Most of the group members are not professional architects.
Collaboration is in our DNA. If our design is chosen as a finalist, new members will be welcome to join the team. Our goal is simply to produce the best possible design.
The virtual model is located here: http://maps.secondlife.com/secondlife/2ND%20LIVE/183/91/22
