Adjacent to Allied Waste’s Mussel Rock Transfer Station, the site sits on the coast near the Pacifica-Daly City border. According to a staff report, the site’s upkeep is crucial, because it sits within a landslide-prone area. Maintenance is necessary, staff said, because ground movement and erosion could cause buried waste to be released into the ocean.
The maintenance contract was awarded to the Stoloski & Gonzalez Construction Company of Half Moon Bay, whose $567,675 bid was the lowest among four firms. Staff said the contractor has completed other construction projects at the Mussel Rock site as recently as 2010.
Director of Public Works John Fuller said the city’s primary concern with the project is to make sure groundwater is not contaminated by the landfill. He said although the site is in a geologically unstable area along the San Andreas fault, it’s unlikely that buried garbage could escape from the site into the ocean.
“The chances of actual garbage getting into the ocean are really, really slim,” Fuller said.
Fuller said the landfill, which dates to the 1950s, was closed in 1978 under a Regional Water Quality Control Board order. Groundwater samples are taken monthly and recent monitoring has revealed no potential effects on the environment, he said.
Another important element of the property, he said, is the construction and maintenance of the landfill’s gabion walls, which Fuller likened to large baskets made of heavy chicken wire and filled with rocks. The bottom of the landfill, which reaches near the shoreline, is protected by boulders that must periodically be replaced due to wave action.
According to Fuller, one of the most important aspects of the new contract will be the addition of new boulders to reinforce the bottom of the site. He said the boulders would weigh as much as 4 tons each. While the city is planning to study the feasibility of relocating the landfill to a less environmentally sensitive site, Fuller said many factors need to be considered. Some potential concerns would include environmental impacts with the use of trucks, as well as possible impacts on nearby neighborhoods due to the trucks.
Fuller said another issue is that the landfill, which is covered with soil and vegetation, has become an open space that residents are accustomed to using like a park.
The location is popular with dog walkers and paragliders, he said, and Daly City is proposing various improvements designed to make the site more parklike. Fuller said likely improvements would include benches, picnic tables, new signage and changes to the parking lot to accommodate people with disabilities.