In a decision bursting with symbolism, the California State Water Resources Control Board recently announced its intention to draw down the main water supply reservoir for a half-million people to only 12 percent of capacity by September 30. Lake Folsom on the American River — the main water source for Roseville, Folsom, and other Sacramento suburbs — will plummet to 120,000 acre feet by that date, according to a forecast by the water board, which announced the plan at an unusually lively Sacramento workshop on June 24.

The artificial lake will therefore be only months away from turning into a dreaded "dead pool," a state in which a reservoir becomes so low it cannot drain by gravity through the dam's outlet. Such an outcome would leave area residents scrambling for water — if recent predictions of an El Niño weather pattern fizzle and rain fails to appear later in 2015. If that were to happen, then Folsom could be a harbinger for the rest of California.

Indeed, as the American West lurches through its fourth summer of an historic drought, numerous major reservoirs are at or near historic lows relative to the time of year. New Melones Reservoir on the Stanislaus River in Calaveras and Tuolumne counties, which was only 16 percent full as of last week, appears likely to meet the same fate as Folsom this year. A study by UC San Diego's Scripps Institution of Oceanography in 2008, three years before the current drought began, warned that the nation's largest reservoir, Nevada's Lake Mead (which supplies much of Southern California), has a fifty-fifty chance of running dry by 2021.

State and federal water management officials have contended that the current state of emergency has come to pass due to a natural disaster beyond their control. Water board member Steven Moore has called the drought "our Hurricane Sandy." In April, after Jerry Brown stood on a Sierra summit barren of snow and announced the state's first-ever mandatory water restrictions, an official press release from the governor's office asserted that for "more than two years, the state's experts have been managing water resources to ensure that the state survives this drought and is better prepared for the next one."

But according to critics, the opposite is true. One of the main reasons that California's reservoirs have plummeted to nearly cataclysmic lows, they say, is that federal and state water managers sent enormous quantities of water in recent years to senior water rights holders, especially water districts that supply agribusinesses in the dry San Joaquin Valley. "Much the way Congress and federal regulators gave Wall Street a huge legal pass and billions in bailout money for crashing the US and global economies last decade, so does the State Water Resources Control Board coddle state and federal water projects and their thirsty contractors for managing their water supplies to the point that the systems on which they depend are themselves circling the drain," said Tim Stroshane, a water policy analyst for the conservation advocacy group Restore the Delta.

Stroshane notes that, in 2012, the first year of the drought, the US Bureau of Reclamation and California Division of Water Resources (DWR), which manage the Central Valley Project and State Water Project, respectively, awarded full water allocations in the hopes that 2013 would be a wet year. And while the projects slashed allocations to zero in 2014-15 for so-called "junior water rights contractors," senior water rights holders have still received close to their full allotments.

From December through April, the Bureau of Reclamation and DWR pumped 1.25 million acre-feet of water from the Sacramento-San Joaquin River Delta into California's southern canals and reservoirs, thereby depleting an already limited cold water supply in Lake Shasta and other Northern California reservoirs.

Despite the current dire situation, California water officials have continued to defend their management practices during the drought. "The water we provide has been essential to agriculture and municipalities throughout the state, and we've cut back as much as we can to maintain the supply," said Doug Carlson, a spokesperson for the state Department of Water Resources, in a recent interview.

But a growing cadre of environmentalists, fishermen, indigenous people, academics, and even some farmers contend that the basic problem is the dramatic over-allocation of California's rivers. In 2012, Stroshane authored a study of the Sacramento and San Joaquin river systems that determined water rights claims amount to five times more water than what actually flows through these rivers and their tributaries in an average year. A 2014 UC Davis study reached virtually the same conclusion regarding the state in its entirety.

And at the heart of this extreme over-allocation problem is the state's archaic water rights system, which was created more than 160 years ago. This outdated patchwork of rules and legal loopholes creates perverse incentives to pump scarce water supplies, especially if favored elements of the state's powerful agribusiness sector are the ultimate beneficiary. Moreover, aspects of the system are so complex and counterintuitive that many Californians have no idea how it really works. "People understand there are big oil companies that control the political economy of oil," Stroshane said. "They understand less about who controls the water in their own rivers, even where they live. It's incredibly important to understand that."

Although California's dysfunctional water rights system, much like its tax system, has long been considered a political third rail, the historic drought is prompting increasing calls for proposals that would finally address it. And some say that perhaps the best legal mechanism available for untangling the state's water woes is a process called adjudication: a legal framework that has contributed to saving fish and the environment on the Klamath River in Southern Oregon and would determine who really has valid water rights in California, how much water can be used, who has priority during shortages, and even whose water use is reasonable and whose is not.