Television and cinema writer/director/producer Jessica Yu has in the past done imaginative media-mixed documentaries about offbeat outsiders, In the Realms of the Unreal: The Mystery of Henry Darger and Protagonist. The former fencing champion turns mainstream in technique and current-events theme now with Last Call at the Oasis.

Inspired by The Ripple Effect by Alex Prud’homme (who appears), the hour-and-three-quarters comes from Participant Media, parent company for Food, Inc. and Davis Guggenheim’s An Inconvenient Truth and Waiting for Superman. This new one offers no surprises in a mixture of graphics, maps, animated cartoons, old footage including boosterism, present-day visuals, and interviews. The award-winning Al Gore vehicle boasted a highly personal subtheme and was successful by riding the coattails of that skilled, personable speaker. Toned down from Julia Roberts’ brassy representation, the real legal consultant Erin Brockovich-Ellis is as much spokesperson as any in Yu’s film, given the most time but also, like the former senator and vice president, a persuasive presence.

In contrast to, say, the Flaherty school of narrative story, the current breed of advocacy journalism non-fictions is argumentative. They present one side of the question in assuming that their point is incontrovertible. In reality, they preach to the choir, and it is doubtful that unbelievers are proselytized.

That argument maintains that clean water is a finite quantity, at present recyclable only to a degree, but that burgeoning populations, wasteful individual and group use, climate change, corporate greed and short-sighted venal governmental bureaucracies have pushed the planet to the tipping point. In this century, “blue gold” will become more valuable than black gold petroleum, wars will be waged over it and millions die for lack of what Westerners take for granted.

Irma Salina’s 2008 Flow/For Love of Water covered the same territory but concentrated on the recent, lucrative bottled-water phenomenon. Yu’s film spreads itself thin in casting a wider net, one which does, notwithstanding, certainly consider that particular business. In fact, its more humorous moments detail attempts to brand and advertise bottled recycled sewage, with Jack Black as shill to overcome the “yuck factor” as effectively as has Singapore.

Short scenes show baptism in the shriveled, polluted River Jordan and Third World women head-balancing jerricans of brown water contrasted with Western shoppers lugging boxes of the bottled stuff. Images show drought and livestock bones and retreating mountain snows, along with deeper consideration of strapped farmers and cattlemen in catastrophic dry Australia, a foretaste, it is said, of what is to come in this hemisphere.

Though numerous bottled-water companies are European, the biggest user-waster is the United States. Cleveland’s flaming Cuyahoga River appears for seconds, as do other stagnant non-streams like the Rio Grande, but more time is given to Las Vegas’ fountains and green watered lawns as Lake Mead shrinks, hydroelectric Hoover Dam is threatened, underground water tables/aquifers are depleted, and the desert gambling Mecca desperately projects intra- and interstate pipelines.

California, however, sets the glaring bad example, as Steinbeck’s Central Valley loses its countrywide agricultural supremacy. Much of the fault lies with methane-based agribusiness techniques, chemical dumping, and defanged supervisory agencies like the EPA. Individual villains are noted, like businessman and former vice president Dick Cheney and his Halliburton Company’s hydraulic fracking for natural gas, which process poisons trillions of gallons of wastewater and (according to an external source) “has a greenhouse gas footprint larger than that of coal.”

Among specialists who participate in both the Salina and Yu films is biologist Tyrone Hayes, whose male laboratory frogs turned hermaphroditic from water containing runoff Atrazine, the most profitable pesticide in this country. That University of California-Berkeley professor-activist has been bullied and threatened; while Brockovich-Ellis does not bring that up in her warnings about deadly hexavalent chromium in small towns or before Congressional committees, she continues to inform and advocate across the country.

Technology has brought immeasurable benefits but also grave perils. With global population to exceed nine billion before mid-century, Sustainable Development Goals, SDGs, need implementation now, not tomorrow. Moderns speculate that Mayan Chichén Itzá and Khmer Angkor Wat fell victims to population growth coupled with water mismanagement. LCO sounds today’s clarion call, though one wishes it and its brethren would devise new screen formulae to blow that trumpet.

(Released by IDP/ATO and rated “PG-13" for some disturbing content and brief strong language.)