Of the five areas of contamination in the Basin, the Baldwin Park Operable Unit (BPOU) is considered the most significant because of the geographic size and degree of contamination. For this reason, the United States Environmental Protection Agency prioritized this area for investigation back in the late 1980’s. By 1994, there was a general consensus on the technical approach including a financial arrangement whereby sales from the water produced by the treatment plant would be used to offset the costs of the project. However, just as designs were being prepared, the discovery of perchorate prompted a complete reevaluation of cleanup plans.
In 1999, due to the critical need for immediate action, the San Gabriel Basin Water Quality Authority (WQA), the Main San Gabriel Basin Watermaster (Watermaster) and the Upper San Gabriel Valley Municipal Water District joined resources and began implementation of the plan by constructing the first facility to treat both perchlorate and n-nitrosodimethylamine for drinking water at the La Puente Valley County Water District (LPVCWD) well site. Following the success of the LPVCWD project, WQA prescribed additional early actions that built on the LPVCWD project development model.
In 2002, eight of the 20 BPOU Potentially Responsible Parties entered into a comprehensive project agreement with WQA, Watermaster and local purveyors to fund the prescribed 22,000 gpm cleanup. The agreement formed the BPOU Project Committee which meets monthly to manage the projects.
As of 2007, the construction of the various projects is mostly complete and the Project Committee is looking at ways to optimize and reduce the 30-year operating costs with emerging technologies.