Water Safety

Redwood Landfill and Recycling Center's top priority is to ensure the protection of Petaluma Marsh. We have a number of systems in place to ensure that we protect the natural beauty and ecological diversity of our area. These include a natural clay liner and a comprehensive leachate collection and removal system. Our water protection systems are regulated by the state of California through the San Francisco Regional Water Quality Control Board.

Natural Clay Liner

In recent years, landfills have used synthetic liners to separate waste from the ground beneath the waste. These liners must meet specific standards regarding permeability to ensure the protection of the soil. Redwood Landfill is built on top of a natural clay liner that averages 20 to 40 feet in depth. The Regional Water Quality Control Board has determined that this natural liner meets and/or exceeds, the applicable permeability requirements designed to protect water quality.

Leachate Containment

Redwood, like most landfills, produces a substance called leachate. Leachate is similar to the liquid that sometimes collects in your home garbage pail. It is the natural precipitation from household waste materials and other liquid. Leachate is unpleasant, and can be unsafe in concentrated forms. In more than four decades of independent water quality monitoring, there has never been evidence of a leachate leak at Redwood.

Redwood's leachate collection and removal system includes an extensive network of trenches, pipes, and pumps that gather leachate and convey it to an engineered impoundment on site.

To prevent any leakage of leachate from the landfill into groundwater or other surface areas, Redwood has constructed a sophisticated and highly protective fluid containment system. Our system is tested by an independent water quality testing lab that collects and tests samples from groundwater wells on a quarterly basis. We are pleased that decades of regular testing have confirmed that no leakage is occurring. Oversight of the testing and results from these tests are reviewed and on file with the San Francisco Regional Water Quality Control Board.

Compaction and Upward Gradient

The physical nature of the landfill, combined with Redwood's engineered containment system, ensures that the liquid from the landfill does not migrate into the surrounding environment. In fact, brackish water contained in the underlying clay actually is pushed up from the clay beneath the landfill rather than seeping downward. This occurs because as the weight of the landfill compacts the clay liner underneath, creating a very slow upward flow of water into the waste. The water in the landfill is then collected in trenches that surround the perimeter of the landfill footprint. The slough and bay are protected as a result. As a further safety measure, and as required by the regulatory agencies, wells beyond the perimeter of the landfill are regularly monitored to ensure that the natural environment is not impacted.