By Wendy Wert
Sewer Leaks Editor
On April 24, the Los Angeles Basin Section (LABS) of California Water Environment Association (CWEA) held the annual installation banquet. The featured speakers at the event, Joe Houghton and Dave Haug, presented an overview of the Clearwater Program.
The Sanitation Districts of Los Angeles County (Districts) manage a wastewater treatment system that serves over 5 million people in Los Angeles County. The Districts’ system includes 11 wastewater treatment plants, two tunnels extending from Carson to White Point on the Palos Verdes Peninsula, and four outfall pipelines that run along the ocean floor and discharge treated wastewater offshore. Projected population growth in the service area combined with existing infrastructure constraints such as design life, capacity, and condition led the Districts to develop the Clearwater Program.
The Clearwater Program is a Districts-wide strategic planning effort that requires partnering among teams of professional engineers, scientists, and environmental consultants from multiple disciplines. Because this infrastructure is a vital component of community health, welfare, and sustainability, a key to the programs success is the commitment to public outreach and stakeholder participation. This was demonstrated on April 16, 2008 when the Clearwater Program was recognized for exceptional achievement in Public Outreach at the state level by the California Water Environment Association.
A portion of the Districts mission is to provide environmentally sound, cost effective wastewater infrastructure. In order to ensure environmental responsibility the Districts must assess the condition of it facilities. The existing tunnels under the Palos Verdes Peninsula were built in 1937 and 1958 and have not been inspected in almost 50 years. The existing outfall system has reached its design capacity, therefore both tunnels must be operated constantly. A new tunnel and ocean outfall would provide additional capacity and redundancy that would support system inspection and maintenance activities. In addition, seismic reliability would be improved.
Multiple alignments within the area of consideration (shown above) are being researched and analyzed by engineers. The possible new tunnel and ocean outfall could be located anywhere in this region. There are two reasonable corridors for the outfalls: the Palos Verdes Shelf, around 1-1/2 miles offshore, and the San Pedro Shelf, approximately 6 miles beyond the
breakwater. The estimated cost to construct a tunnel/outfall in today’s dollars would be $1 billion to $2 billion.
Public meetings, workshops and hearings are an integral part of the facilities planning process. This on-going effort is expected to result in a decision point at the end of 2009. If the decision is made to construct a new tunnel and ocean outfall, the final design process will take approximately 3 years, followed by 8 years for construction. The entire project could be completed in 2020.