Imagine one low-elevation trail for bikers, joggers and hikers starting at Eaton Canyon Nature Center, crossing Altadena and sloping back down through the Rose Bowl to link up with paths through the Arroyo Seco.

Imagine the same path linking to a paved traffic-less bikeway that runs all the way to Long Beach and a second path for runners, dog walkers and everybody else.  Access to the trail system would be every couple of blocks, allowing residents everywhere a way to move between towns without getting in their cars.

It would link to other existing trails in Altadena, including the ones at the Cobb Estate, Millard Canyon and in nearby areas like Eaton Canyon and Hahamongna Park.  Other future trail linkages to the San Rafael Hills and La Canada Flintridge could also be possible.

That's the dream of the Emerald Horseshoe, a plan that is being pushed by several conservancy and open-space groups, including the Altadena-based Arroyos & Foothills Conservancy. (To get a feel for the individual issues on parts of the Emerald Horseshoe, please check our interactive map.)

The project has many, many obstacles to overcome to become a reality, and nobody wants to speculate on when it might actually be completed or how much it might end up costing.  Even finishing the Altadena Crest Trail, which would be the backbone of the Emerald Horseshoe through Altadena, is not guaranteed to happen.

Still, the conservancy has a plan for more than 20 miles of trails that includes dedicated bikeways, gardens, a bike plaza in Pasadena and even the possible restoration of river habitats along the Eaton Wash.  The goal may not ultimately be attainable, but it is great goal to have, said Nancy Steele of the Arroyos & Foothills Conservancy.

"It's kind of the role of the non-profit to put out a big vision," said Steele. "It's the government's role to see how well it can translate that vision to reality."

Progress and challenges on the Altadena Crest Trail

The conservancy took a big first step earlier this month when it announced the purchase of a three-acre lot in the Rubio Canyon area, where there is a gap in the trail.  The lot was slated possibly to be developed.  The conservancy is now seeking to raise $50,000 to help buy the remaining 18 acres it needs to complete that part of the trail.  The total cost of the acreage will be $600,000.

Through Altadena there are other gaps.  One of them in the area between the top of Fair Oaks Avenue and the Chaney Trail runs through a lot of private property.  The trail used to exist there decades ago, said local trail activist Lori Paul, but was never officially marked and fell into disuse.  Now reviving it will require the participation of local property owners.

"Some of the owners do not want a public trail coming through their property," said Paul, who lives right at the edge of the so-called "Skylane Gap."

She said she tries to point out to reluctant neighbors that most of the trail use will be by people who live right along it but fears that there is too much opposition to the idea.

The third major gap in Altadena is in the La Vina neighborhood, where some trails do exist, though there is a gap.  The possibility for that gap being closed drastically improved last spring after the local neighborhood association agreed to settle a lawsuit to block access to the trails.

Jan Takata, of the county's CEO office, said a settlement is being finalized, and once it is finished, the county can begin plans for trail construction.  That could happen as soon as this Spring.

Opening up the Eaton Wash

The even more challenging parts of the project may come outside of Altadena.  The bike and jogging trail segment that would run from just south of the Eaton Canyon Nature Center all the way to an existing bike corridor that starts in El Monte would run through the Eaton Wash, a concrete-lined channel that is operated by county flood control authorities.

The wash is already lined by access paths that would only need to be improved, but they are currently locked behind gates and only accesible for county engineers and those who are daring enough to climb the tall fences to get inside.

The frustrating thing is that if the county would agree to open the wash, it would be very easy to convert to a trail, said Holly Thompson, the planner who developed the plans for the conservancy.

When asked to describe the single biggest obstacle to the project, Thompson's answer was: "in a word, the county."

Takata said he believes the project would be a difficult one for the county to work on.  There are safety concerns about people getting into the channel during a potential flood, and concerns about private property that backs up to the wash.

"It's difficult logistically, because it is basically just a small culvert," Takata said.

At the same time, he added, county officials are not definitively opposed to the prospect of a trail.  There has never been any formal request to study the issue, he said.

Bike Plaza or On-Street Route?

There are other problematic issues with the eastern segment along the Eaton Wash.  The wash disappears underground just north of the 210 Freeway and resurfaces on the back end of a strip mall on the southern side of Colorado Boulevard.

The conservancy's plan calls for a bike plaza in that area that would not only provide a direct off-street path for bikers and joggers, but also a nice landscaped area with a bike shop, ample bike parking and an artificial creek.

Unfortunately, the site where the plaza would be is privately owned, though it is currently an empty parking lot.

Pasadena planners who are working on the project see an on-street segment as more likely, with signage that directs trail users through what would be a gap of about mile.  It would require those bikers and joggers to cross through a heavily-developed commercial stretch north and south of Colorado Boulevard, then head into a residential neighborhood before picking up the trail again.

The idea of a plaza is a great one, said Loren Pluth, the Pasadena planner who oversees Pasadena's contribution to the project.

"It's possible, but the question is where the funding comes from," Pluth said. "This is certainly the plight of every urban trail."

Pluth is already looking ahead to improving the street segment of the project.  He said the city is applying for a grant for that section that could go towards signage and other improvements that would be consistent with an on-street solution.

Bikers in the Arroyo Seco

The west side of the trail system through the Arroyo Seco would also pose some problems for trail users.  Mountain bikers coming down from the hills of Altadena would not be able to cross through the Pasadena section as it is currently constituted.

Users can currently traverse Hahamongna Park and enter the Brookside Golf Course through an access point in the Devil's Gate Dam.  Then comes the heavily-used area around the Rose Bowl, which thousands of joggers and cyclists already use every day.

But south of that is a dirt trail that connects through Brookside Park and into South Pasadena.  It is not well-marked, and bikers are not allowed to use it.

For bikers to gain access one day would require either a paved bikeway or a change in city of Pasadena rules that ban the use of bicycles on dirt paths, Pluth said.

The biggest obstacle

While many involved in the project have named the county government as an obstacle, for others it is landowners reluctant to have trails near their homes.

In addition to the Skylane Gap, concerns have been raised about parts of the Eaton Wash in Pasadena and areas in San Marino that back up to people's backyards.

But as with many government projects, the biggest obstacle could be funding, said Julianna Delgado, a Cal Poly Pomona professor who has done work on regional trail systems in the county, including the Emerald Horseshoe.

She said that if the project had a committed source of funding, she believes many of the concerns over the trail would quickly disappear.

"The physical challenges, the terrain, the materials, are all surmountable," Delgado said. "And politically, there is a lot of support for open space."