Mark and Evan traveled to El Paso to help the City of El Paso Parks & Recreation Department and project lead Quantum Engineering Consulting to plan a mountain bike trail running down from Franklin Mountains State Park to a multi-use path south of Interstate 10.
Local mountain bikers also provided helpful input. When finished, the trail will provide an upper loop as well as the connector, a total of 4 miles.
Aesthetics. The benefits of interacting with Nature continue to become increasingly recognized as a low-cost, effective antidote for the effects of 21st Century living. Recreating on trails improves our physical, emotional and spiritual health. By providing a positive experience, a well-designed and constructed trail encourages people to get out and move through the landscape.
Sustainability. Trails designed and built to be sustainable lighten the land manager’s load by minimizing maintenance to the level that it can, for the most part, be done by volunteers. Avoiding erosion protects resources from sediment migration, head cutting, and user-created trails taken to avoid eroded trail segments. Sustainable trails enhance the user experience by providing a relatively smooth tread for feet and tires. This is achieved primarily by ensuring, both through design and construction, that water runs across and not down the trail. Soil types – more specifically shear strength – determine the allowable grade. (Side slope grade is also a determinant because water will turn and run down a trail with a grade that is more than 50% of the side slope grade.) Decomposed granite is highly erosive, and maximum grade may be as little as 3%; solid bedrock, the other extreme, can be fall-line grade since erosion takes place on a geologic time scale.
All of the above objectives are incorporated as “positive control points,” places the trail needs to go if at all feasible. (Trailheads and intersections for connectivity are examples of positive control points.)
Negative control points, areas to be avoided, include sensitive habitat, cultural sites, and physical features that make construction impossible or excessively expensive.
Construction feasibility. Southwest Trail Solutions approaches design with an eye toward minimizing construction costs where possible. Our extensive experience in trail building in a wide variety of terrain enables us to assess not only if a trail can be built, but how it might be built; if we have a choice between a labor-intensive option and one that can more easily be built without compromising sustainability, aesthetics and user experience, we will recommend the latter.
Primary Route
Constraints. The possibility of future development to the south created a boundary that eliminated some options, but for the most part, these did not affect the route-finding process. The exception is the approach to the gas line road at the southern end, where it forced the trail into the flood plain of a major arroyo. Should a May election preserve this area for open space, we have provided a short (0.15 mile) alternative route to connect to the road.
Description. The route provides a loop option at the upper end and a single, 2.52-mile descent to the gas line. A second route, north of the primary trail, is a .88-mile connector to the primary trail that could be combined to make a 1.68-mile loop back up to the Lower Sunset Trail.
Existing roads and trails in the area showed a good capacity to avoid erosion over a long period of time; soils along the route, with a high percentage of rock content, indicated that grade limitations could easily be sustainable with an average grade of 10%, with shorter runs of 18-20% if needed – and with care in construction.
Route Description. Northbound, from the gas line the trail follows the arroyo for approximately 750 feet, then climbs gently, contouring a side slope before crossing a side drainage. The trail then climbs in a contour – beginning with two climbing turns – that averages approximately 6%, with one short (60 feet) section of 14%. At the point, it turns in a more easterly direction the trail has an average grade of approximately 10% as it climbs to the upper plateau, with a maximum grade of approximately 14% for a short run – about 100 feet. On the plateau the trail levels off to a 2-3% average grade. It drops down into another drainage with a 400-foot descent of 6%, then climbs at a 5% grade, with a short 14% segment, to the ridge top plateau. From there it follows the ridge, with grades varying from 0-10%, but mostly below 5%, all the way to the intersection with the Lower Sunset Trail.
Because this trail is accessible by vehicle from the park, it will provide an opportunity for bicyclists to make shuttle runs for downhill riding.
Secondary Route
Description. While in El Paso the Southwest Trail Solutions team laid out an alternate upper route to link up with Lower Sunset Trail that stays closer to the original concept alignment and avoids potential conflict with the El Paso Water Open Space. The route descends from the Lower Sunset Trail .34 miles north of the intersection with the main route. It drops into a drainage and climbs back out; the climb distance is approximately 1,100 feet, but after the first 200 feet, where the grade is around 10%, the grade is gentle, 2-4%. The total distance of this loop, including Lower Sunset, is 2 miles.
The secondary route can serve as a standalone replacement for the upper leg of the primary route, or if the budget allows it could be built alongside the primary route to allow for additional loop options both from the Lower Sunset Trail and from the bottom of the primary route.