On the edge of the Central Valley is the center of California's water system: the Sacramento-San Joaquin River Delta, where the state's two largest rivers meet.
A plan to restore the Delta by channeling water down south has long been a priority for Governor Jerry Brown's administration. Despite its various names and strategies, the project has been riddled with controversy since Brown first assumed office in the late '70s.
“If we don’t have the project, the Delta will fail, water will not be available and California will suffer devastating economic consequences," the governor said recently at a conference hosted by the Association of California Water Agencies.
The plan to divert Delta water to Southern California faces backlash from Valley farmers and some environmental groups. Generally, farmers believe it could threaten their water supply. Environmentalists against the project think it would do more harm than good to the native ecosystem.
The administration's $15.5 billion plan (some estimate the cost will reach $67 billion) involves building two massive underground tunnels -- 40 feet wide and stretching 30 miles in length.
Supporters of the project, now called the California WaterFix, say the state's water system is outdated and unstable. The cost of doing nothing, supporters say, would be catastrophic. 
"If we had an earthquake that collapsed the levees on the Delta, that would have a huge impact on our state," California Water Program Director at the National Heritage Institute Jerry Meral said. Meral is a former top water official for Brown.
The Delta is home to a variety of wildlife, including 20 endangered species like the Delta smelt. It's also a resource for recreation and the backbone of an annual $500 million agriculture industry.
Currently, the State Water Resources Control is holding its first meetings to consider issuing permits to break ground on the Delta tunnels project.
There's two reasons why the project could be doomed if construction doesn't start this year.
One reason is the lack of financing for further environmental reviews.
"Frankly, we're out of money," General Manger of the Metropolitan Water District Jefferey Kightlinger said.  "None of us are inclined to go back to our boards of directors and ask for more money just to keep an endless study loop going."
The review process up to this point has primarily been paid for by potential project beneficiaries (state water contractors) and partially by the federal government.
Reason number two is the political will to get the project done.
The Brown and Obama administrations support the tunnels project. No matter which party is elected to the presidency in November, the plan will stall as we go into 2017 and the new team needs to get up to speed. Kightlinger said a change in administrations typically causes up to a two-year delay.
The 2016 election year poses other threats, with possibly two measures appearing on the November ballot asking voters to decide the tunnels' fate.
One of the measures is by a wealthy Stockton farmer, Dean Cortopassi, who spent millions on a ballot initiative that would require voter approval for any state issuance of bond money for projects exceeding $2 billion in cost. Like the tunnels.
Another measure has been proposed by Delta-area lawmakers (all Democrats) that would require a vote on any sort of Delta water conveyance system.