The Puente Hills Predicament: The story of a landfill

The Puente Hills Predicament: The story of a landfill

Sara Weir
FOR THE QC

The local Puente Hills Landfill was approved as the site for a new park in 2016, just three years after it closed in October 2013. The plans to build a park on top of the landfill are long-term, and, although it has been two years, there is still plenty of work to be done. One reason for the wait are the issues of building on top of a landfill. 

The Puente Hills Landfill is a historical site in its own way, as it contains building rubble from the Rodney King riots and from major earthquakes, according to the article “Closing America’s Largest Landfill, Without Taking Out the Trash” by Liyna Anwar for National Public Radio. Whether or not the landfill is actually the largest in the United States depends on who you ask. Anwar reports that the waste reached over 500 feet tall before being covered with a layer of dirt to seal it in. 

Although closed and covered with dirt, the landfill is still used for gas-to-energy power generation. This process pumps gases produced by the waste — mainly methane — and burns it to create steam-generated power, as explained on the website for the Sanitation Districts of Los Angeles Country, lacsd.org. 

 Puente Hills Landfill

Puente Hills Landfill

The leakage of both natural gases and leachate, or contaminated liquid that drains from landfills, is one concern for construction of a park. In his article for the San Gabriel Valley Tribune, “LA County approves plan to build ambitious Puente Hills Landfill Park,” Steve Scauzillo says that amenities at the park such as baseball fields are “not acceptable” because it would be necessary to water these fields, which could result in “waste tainted leachate that would seep into the water table.” In other words, the groundwater could be contaminated if liquids or gas seep through the landfill. Lacsd.org’s PDF on the landfill said that the site was chosen because it is not directly above a water supply. However, if any leaks make it past the barriers under the landfill, it is possible they could make their way into a nearby water supply regardless. 

Another issue with building on top of a landfill is the potential for the ground to shift as the waste settles. According to Scauzillo, while the western deck of the Puente Hills Landfill is apparently ready for construction, developers expect the southern and eastern decks to settle up to 125 feet in the next 25 to 30 years. Thus, as Terry Kanakri explains in her article “The Transformation of the Puente Hills Landfill,” the park will be “built in phases over the next 30 years,” while the first park area is set to open in just two years. Developers will have to adjust their plans over the next few decades to deal with a turbulent environment.