What's abundant yet scarce, free yet costly, makes us yearn when we can't get enough but grouse when there's too much around?Water, of course.Some homeowners might think nothing of letting their lawn sprinklers spray aimlessly into the gutter following a downpour, but Texas planners and policymakers are considerably more focused when it comes to long-term management of this precious resource.And thank the rain gods they are.With drought becoming a persistent problem, even in December there are counties -- including Tarrant -- imposing burn bans to prevent wildfires from devouring dry winter grasses on these uncharacteristically warm days.Predicting parched periods is less of an exact science than predicting water needs. Those are growing as Texas adds people, but getting ready for them takes years of preparation and is expensive no matter what option gets pursued.The population of North Texas is expected to double by 2060. And by that time, the Tarrant Regional Water District estimates, the 11-county area it serves (including the cities of Fort Worth, Arlington and Mansfield) will need 400,000 acre-feet per year more than the current supply.One acre-foot is about 325,000 gallons, so that forecast is a mighty hydration challenge.The TRWD has collaborated with Dallas Water Utilities on a $2.3 billion pipeline to bring water from East Texas reservoirs. But a project timeline on the TRWD website shows construction starting in 2014, with startup not completed until 2021.Efforts to haul water from Oklahoma have ground through litigation since 2007. If the U.S. Supreme Court agrees to hear arguments in the case, that would be a temporary move in North Texas' favor. But it would mean more months, if not years, before there's a resolution.The key issue in dispute is whether a water-use compact among Texas, Oklahoma, Arkansas and Louisiana bars Oklahoma from passing laws that prevent the Tarrant Regional Water District from taking water from a Red River tributary on the northern side of the state line.A federal district court and the 10th U.S. Court of Appeals in Denver ruled against the TRWD. But last week, the U.S. solicitor general, whose office represents the federal government at the Supreme Court, urged the justices to take up the case -- and sided with TRWD's interpretation."The better reading of the compact is that a state may divert a portion of its share of ... water from outside of its boundaries, at least when necessary to exercise its 'equal right' to excess water in that sub-basin," the solicitor general's brief said. (bit.ly/VJZ1Rg)"This case implicates important state interests protected by an interstate compact, and the court of appeals' decision has potentially great practical consequences for the availability of water in a major urban area in Texas. Those concerns justify this Court's review."As the SG points out, though, even if TRWD persuades the justices that Oklahoma's water agencies are wrong, issues such as how much TRWD might be able to get and when would have to be determined, possibly in lower court proceedings.But North Texas isn't alone in its thirsty search. Even Lt. Gov. David Dewhurst considers water a worry that requires legislative attention in 2013. He recently said diverting $1 billion from the rainy-day fund to create a new water development bank could assist municipalities in constructing reservoirs to meet demands."We're going to need to double our potable water supplies in the state of Texas," he told a Dallas Regional Chamber audience Nov. 29.Environmentalists argue that the cheapest option is using less water, and that must be part of the solution.Meanwhile, the University of Texas at Arlington is trying to build support for an Urban Water Institute that can study such regional water issues as the economic impact of water prices, the Star-Telegram's Bill Hanna reported Sunday.Water might be too dull for water-cooler chat, but it's too important to be taken for granted.