Comment on City chips away below Coit Tower to stabilize hill’s slope

In 2012, part of the hill collapsed, sending several colossal boulders down the northern slope of Telegraph Hill and into the parking lot of the condominium building at its base. “This is a unique area — it was an undocumented quarry in the 1800s, and they would blast the hillside indiscriminately,” said Rinaldi Wibowo, the project manager at Public Works overseeing the work. The work took on extra urgency last week, when two separate rock slides occurred — one inside the project site and another near the project area — from the recent rains. No one was injured, but San Francisco Public Works spokeswoman Rachel Gordon said the first slide sent more than a ton of rocks onto Chestnut Street below. “We know at some point the (stabilization work) has to be expanded to other areas, but these are the resources we have at this point,” she said, adding that the city focused on portions of Telegraph Hill where the worse slides have occurred in the past. In recent weeks, crews from GeoStablization International, or GSI, which the city hired to do the dangerous work, have been “scaling” the steep cliff — workers rappel down to chip any loose chunks of rock and vegetation from the hillside. The resulting crashing rocks, which can be heard for blocks around, are stopped at the bottom by chicken wire and bales of hay. The cost of the project is being split between Public Works, the Recreation and Park Department and the Department of Building Inspection. “I want to be out here to reinforce the need to take care of this,” he said, adding that the 2012 rock slide — which crushed a car but caused no injuries — was “very scary for residents” in the adjacent condominium complex.