An artist’s rendering of a revitalized Kapalama Canal imagines an idyllic urban park: wide sidewalks, a graceful bridge, people walking and picnicking along the canal’s banks, boaters paddling on its waters.

It’s a vision city officials hope to sell at a community workshop in Kalihi tonight.

It’s a wonderful idea, of course. Currently, the scruffy area, bordered by a mix of warehouses and small businesses, has little to recommend it. The most prominent feature along the canal is a chain-link fence recently installed to prevent homeless people from camping there and dumping offal into the water.

As with any public project, the problem lies in execution. Plans for the “linear” park go back decades. In the 1950s, said Irene Fujimoto, past president of the Kalihi-Palama Community Council, “it was one of our biggest projects.”

Times and circumstances have changed. Community-organized cleanups aren’t enough. Today’s plans are necessarily ambitious, but the city likely doesn’t have the resources or ability to make them a reality on its own.

Turning the 4,000-foot stretch of grassy streambank into a vibrant, pedestrian-oriented gathering place will require the cooperation and, more important, the contributions of the area’s stakeholders, especially the two biggest ones: Honolulu Community College and Kamehameha Schools.

It should be worth the effort. The Kapalama rail transit station will be close to the canal, and the transit-oriented development (TOD) plan for the station is the most ambitious for the three rail transit stations in the vicinity — Middle Street, Kalihi and Kapalama.

The plan includes “a new high-intensity mixed-use district” that will add “residences, public facilities, and neighborhood shopping, with the tallest heights and highest building intensities surrounding the station.”

The Kapalama Canal park would serve as the “major open space” for all this development. So it needs to be as attractive as the artist’s vision, and match the scale and scope of the redeveloped area surrounding it. And because a new park, properly designed and executed, would make the area an attractive place to live and spend money, the companies and organizations who stand to benefit should contribute to the park’s cost and development.

The new park would draw rail riders to the area for shopping and recreation. But more important, it would serve local residents living in new affordable-housing projects near the station that TOD planners should ensure are built.

Thus far, the city’s efforts to encourage development of affordable housing near train stations has been halting or nonexistent. For instance, the planned Mana‘olana condominium-hotel tower, located near the Ala Moana rail station, would contain no affordable housing at all. Yet the project would use interim transit development policies to gain exceptions to height and density requirements, possibly in exchange for 20 affordable rental units within a mile of the Ala Moana station or up to $3 million in in-lieu fees.

The city will need to be less forgiving and more aggressive in working with developers to build affordable housing in the Kalihi area, especially near the Kapalama Canal.

And while a beautiful new promenade would attract more people, there’s a legitimate concern that some of those people will be homeless citizens with tents and shopping carts.

“Who doesn’t want it to be beautified, but are we preparing a place for the homeless to be more comfortable?” asked Shirley Hilton, owner of Kahala Pacific Floors, whose store is next to the canal.

Fear of the homeless should not dictate public planning. Nonetheless, the city and its private partners will need to ensure that the park is used for its intended purpose, perhaps through nightly closures or rules similar to those enforced in Waikiki.

The community workshop is scheduled for 6 p.m. today at Palama Settlement Dining Hall, 810 N. Vineyard Blvd.