Brock Reservoir: Sharing the cost, sharing the reward

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Brock Reservoir

(The story below is built around a recorded interview with key members of the Brock Reservoir team: Chuck Cullom, Central Arizona Project; Bill Hasencamp, Metropolitan Water District of Southern California; David Palumbo, Bureau of Reclamation; and Colby Pellegrino, Southern Nevada Water Authority.)

Water can be a contentious topic in the West and especially the Colorado River. But at a time when many were gearing up to fight over the Colorado River, a group water managers came together and showed that collaboration is a powerful strategy to achieve a solution that works for everyone. In this case, it was the collaboration of the Bureau of Reclamation (BOR), Southern Nevada Water Authority (SNWA), Metropolitan Water District of Southern California (MWD) and Central Arizona Project (CAP) who came together to build Brock Reservoir. The team funded and constructed the first Colorado River infrastructure project designed solely to conserved water in the Lower Basin.

Brock Reservoir is an off-stream storage reservoir located near Calexico, in Imperial County, California. The reservoir is on the All American Canal which diverts Colorado River water from Imperial Dam, the last major diversion in the United States before the River flows into Mexico. Brock Reservoir stores water that has been released from Lake Mead, about 300 miles upstream of Imperial Dam, to meet downstream water orders that are cancelled after release from Lake Mead. The water orders take about 5 days to flow from Lake Mead to Imperial Dam, and frequently water orders change due to local precipitation. Brock Reservoir temporarily captures water released from Lake Mead and arriving at Imperial Dam but no uses for delivery since rain has reduced demands. Prior to construction of Brock Reservoir, this water was not put to beneficial use by either country, and was wasted.

When SNWA was having some supply concerns in the early 2000s, they saw the project as an excellent way to address their issues by reducing system losses and conserving this water. SNWA, working with BOR, evaluated the opportunity to conserve the lost water, benefit Lake Mead, and create a temporary water supply called Intentionally Created Surplus (ICS) from the conservation.

“Seeing that our demand in the Las Vegas Valley was going to continue to grow, we needed a bridge resource to get us from our Colorado River resources to whatever new water resources we might need to develop,” said Colby Pellegrino, SNWA Colorado River Programs Manager.

At the same time, California was experiencing a drought and MWD asked if they could join; CAP then followed suit.

“Solutions are better developed from a broader group of participants,” said Chuck Cullom, CAP Colorado River Programs Manager.

Together, the team with diverse interests worked out the project details. BOR would oversee the project, which included solving engineering challenges related to the location.

“It’s sand, constructing that reservoir in the sand…and then we have seven miles of canal and a siphon that goes under an interstate that our water conveyance groups designed in our technical service center in Denver,” said David Palumbo, BOR Deputy Commissioner of Operations.

On the financial end, 2/3 of the project was funded by SNWA, and 1/6 each by CAP and MWD.

In return, each entity would get intentionally created surplus (ICS) credits in Lake Mead; 400,000 acre-feet for SNWA and 100,000 acre-feet each for CAP and MWD.

“It’s cost effective and it has been probably the single biggest reason that we’ve stayed out of shortage all these years by saving this water every year and keeping it in Lake Mead,” said Bill Hasencamp, MWD Colorado River Resources Manager.

Brock Reservoir has reduced lost water in the Lower Colorado River system by approximately 60,000 acre-feet per year. This is equivalent to almost 1.0’ in Lake Mead that was being lost every year. In addition, the project has created ICS which CAWCD is using to mitigate the impacts of DCP on CAP water users. The project will continue to provide conservation benefits for the life of the facility, expected to extend for more than 50 years. All in all the project is a success for the partners and for all Colorado River water users in the United States and Mexico.

Read the complete transcript from the interview.