GARANCE BURKECADIZ, Calif. (AP) â¿¿ Off historic Route 66 in the heart of the California desert the barren landscape of dry scrub and rock abruptly gives way to an oasis of tall green trees heavy with lemons and grape vines awaiting next month's harvest. Some believe this lush farm in the unlikeliest of places also sits atop a partial solution to Southern California's water woes. By tapping into an aquifer the size of Rhode Island under the 35,000-acre Cadiz ranch, proponents say they can supply 400,000 people with drinking water in only a few years. If the plan sounds familiar, it is. A decade ago, Los Angeles' Metropolitan Water District narrowly rejected it when it faced widespread environmental opposition. A scaled back version has resurfaced with a greener pitch, momentum from five water agencies and what the company claims is better science to win over skeptics. "Do we need additional water supplies? Yes. Do we need groundwater storage? Yes," said Winston Hickox, a Cadiz Inc. board member who headed the California Environmental Protection Agency. "The question is 'OK, environmental community, what are your remaining concerns?' I don't know." But conservationists including the Sierra Club remain worried. Critics say the company has misrepresented the size of the aquifer and that mining it could harm the threatened desert tortoise, bighorn sheep, as well as the nearby Mojave National Preserve which has some of the densest and oldest Joshua tree forests in the world. Concerns over rare desert species were also echoed by state Department of Fish and Game biologists in March. Conservationists also worry tampering with an aquifer in a place where water is so scarce could cause dust storms. "There's a lot of unknowns here but we think this project has the potential to adversely affect air quality, draw down water resources and alter the flow of groundwater beneath the Mojave Preserve," said Seth Shteir with the National Parks and Conservation Association, which plans to scrutinize an environmental review of the project, expected to be released this month.