After completion, the $230m, 110 million-gallon storage facility will be the largest underground reservoir in the Western US.

Situated between the 134 and 5 freeways near Griffith Park, the new reservoir will replace the storage once provided by the Silver Lake and Ivanhoe reservoirs.

Its technology and design will enhance LADWP’s ability to manage the quality and reliability of the water stored there.

The Headworks Reservoir project will allow the city to move water from the Silver Lake and Ivanhoe reservoirs, and address state and federal water quality compliance deadlines.

Upon completion of Headworks West in 2018, both concrete structures will be buried under two to three feet of soil and native vegetation.

Apart from underground storage, the site will feature a 4MW hydroelectric power plant.

Los Angeles Mayor Eric Garcetti said: "The time to invest in the next generation of water infrastructure is now — and we are seizing the moment."

"The security of our water future depends on creating more local storage, and I am proud to say that we are putting shovel to dirt on this landmark project."

LADWP general manager, Marcie Edwards said: "This project is an example of the many infrastructure improvements we are undertaking throughout the city in order to continue providing our customers with reliable, quality water well into the future."

"It is one of the vital components in our efforts to replace aging infrastructure, meet our regulatory obligations to ensure the finest drinking water for our customers, and ensure the reliability of our water service."