Sunset Cliffs Park is eroding, and a long-awaited plan is in development to improve the way the city catches stormwater, moves it across the fragile bluffs and pipes it into the ocean without causing further damage. But at a public forum July 20 at Robb Field, citizens expressed concerns about costs, possible conflicts with a parallel effort to develop park trails and whether much of the hardware could be eliminated through green alternatives. Nearly three dozen residents showed up to get a progress report on the so-called comprehensive drainage study, a project headed by the city’s Park and Recreation Department. They asked questions and sized up six maps that lined the walls of Jim Howard Hall, each with a different alignment of pipes, catch basins and outfalls. The final design will be selected by the department director after weighing the comments, said Paul Jacob, an associate engineer who is heading up the effort. Depending on the alternatives selected, the project could cost as much as $6.8 million, according to a report from the consultant, Dudek Environmental and Engineering Services. The problem originates from rain that hits roofs, streets and sidewalks and heads toward the ocean across the park, said Dudek’s Steve Jepsen. Existing infrastructure is either too small or in a state of disrepair, he said. The plan seeks a 50-year solution that emphasizes low-cost maintenance and sensical, by-the-book engineering practices, Jepsen said. But several citizens spoke in favor of fewer pipes and more natural measures: wetlands, containment basins, rain barrels and home landscaping. Others worried the solution was worse than the problem. “What you’ve planned here literally destroys the park, because you’re piping right through it,” said Suhail Kahlil, who chairs the Peninsula Community Planning Board. He called for an analysis on costs versus benefits. “It’s a bunch of pipes and sand bags,” he said. “That’s not comprehensive.” Jean Nathan echoed those sentiments. “We’ve all contributed to the runoff. and it’s time to treat the cliffs gently,” she said. Jepsen said the pipes would be installed using angle drilling or other trenchless technology. At the base of the cliff, new outfalls would be encased in a 6-by-6 concrete box with an energy dissipator to slow the release of water. Special texturing and coloring would help the boxes blend in with the native rock structures, he said. Belinda Smith of the Surfrider Foundation said a wetland could be used to store water instead of piping it to the ocean. “We’d like to see a lot more capture,” she said. “We’re sending such filthy water out there. It’s really a crime.” Jepsen said catch basins would filter oil and trash from the water but it would not screen out pesticides. Jim Peugh also liked the idea of a wetland for water treatment. “The park doesn‘t lose anything. You get a lot more diversity of wildlife,” he said. Jepsen said green alternatives could cost too much to maintain. “[That’s the] reason engineers like pipes and concrete. Holistic approaches — rain gardens and cisterns — are terrific, but when we design municipal facilities, we’re assuming current level of maintenance and a 50-year design life. These are principles frequently dictated [to us],” he said. Smith disagreed. “It’s easier to organize a community cleanup of a wetland than a big concrete box,” she said. Norm Allenby, a member of the Peninsula Community Planning Board, said the study should expand its vision to the entire watershed. “All I see is an approach that concentrates the flow of water and discharges it as quickly as possible to the beach,” he said. “In an urban watershed, properly designed and properly handled, there should be no runoff from a landscaped home, or campus or ballfield.” Dedi Ridenour said she didn’t like the idea of installing more stormwater pipes on Sunset Cliffs Boulevard. “It’s too fragile,” she said. “It would not protect the park. It’s a waste of money and it’s a boondoggle.” Despite the added pipes, the plan would fail to address much of the uncontrolled runoff, said Craig Barilotti, who brought a map of the park south of Ladera Street identifying around two dozen areas of concern. “It’s a real omission. And the problem is it interferes with the trails,” he said. No date has been set for the final version of the comprensive drainage study to be finalized, Jacob said. The city hopes to have the necessary permits in March for a related project to develop trails and restore vegetation in the park.