First surface water augmentation project via indirect potable reuse (IPR) permitted in the State of California, providing a local, sustainable drinking water solution
At a glance
East San Diego County is one step closer to providing their community with a reliable new drinking water supply. The project will transport purified water from the new East County Advanced Water Purification (AWP) treatment facility to Lake Jennings, located in the arid eastern portion of San Diego County. It provides a new local, sustainable drinking water solution while also reducing energy consumption and operating costs. The project will also convey wastewater supply to the City of San Diego (City) during peak flow periods and transport the brine/centrate generated at the AWP to the City for treatment and disposal.
The challenge
San Diego County does not have an economical groundwater supply; in this area groundwater is scarce and located deep in their aquifer, leaving residents and businesses to rely on imported water, state aqueducts, and the Colorado River. Currently the County transports their water supply from up to 500 miles away, and with the rising costs of energy to import the water, it is important to reduce their reliability and diversify their supply.
The new water recycling, advanced purification and solids handling facilities, pipeline, and pump station, is the first project permitted for surface water augmentation via IPR in the State of California. Water will be recycled, purified further, discharged into Lake Jennings; a local water reservoir, and then get treated again at the Helix Water District’s Levy Treatment Plant to become drinking water, creating a local sustainable water supply to meet the demand for up to 30% of the County’s drinking water and reduce their dependence on imported water.
Our response
The project is being delivered in five separate progressive design-build packages. GHD teamed with Orion Construction as the designer of record and were awarded Packages 2 and 4.
Package 2 is the design of a 10-mile, 24-inch welded steel product water transmission pipeline, dechlorination facility, where the water must be treated before it is discharged into Lake Jennings, and a subaqueous outfall pipeline and diffuser manifold in Lake Jennings.
Package 4 includes approximately 9-mile section of an overall 12-mile brine/centrate pipeline that will run from the AWP treatment facility to the City’s trunk sewer for treatment and disposal. This Package also includes rehabilitation of an existing 48-inch parallel wet-weather bypass pipeline that serves to convey additional wastewater supply to the City for treatment and disposal during peak flow periods or in the event of an AWP treatment facility shutdown. As part of this project, we are using the existing 48-inch pipeline as a casing and pulling through the smaller brine/centrate and wet-weather bypass pipelines using the sliplining construction method.
We are partnered with Orion Construction; our previous experience working together on over 30 design-build projects ensured confidence in our ability to complete these packages efficiently and on schedule.
The impact
As a result of the project, the East San Diego County community will not only have a new sustainable drinking water source, it will also create energy to reduce their operating costs to provide more competitive rates to their customers.