Change is inevitable for the Tarrant Regional Water District board.The question is how soon.Board President Vic Henderson of Fort Worth is 75 and in his 29th year as a director. Vice President Hal S. Sparks III of Fort Worth, 72, has served 26 years. Jack R. Stevens of Azle, the board secretary and a relative newcomer with 10 years service, is 69.Along with directors Jim Lane and Marty Leonard, they have led the way in planning a system of lakes and pipelines to serve local and regional water needs for the next 50 years.But they have been less successful at nurturing younger and more diverse board leadership to continue that work for another 50 years.Henderson, Sparks and Stevens are running again for re-election May 11. The water district election will appear only on ballots inside the taxing district, which includes much but not all of Fort Worth plus Azle, Edgecliff Village, Westworth Village, Westover Hills and part of River Oaks.Generally, the incumbents argue that they should be re-elected to continue their successful projects, particularly the construction of a new $2.3 billion pipeline from an East Texas lake to be shared with Dallas Water Utilities.A growing North Texas metropolitan area will need almost twice as much water in the next 50 years, and the nearest place to find it is either East Texas or Oklahoma, where the district pursued a lawsuit for access to water under an interstate treaty.Directors also say they want to expand the board's "Lawn Whisperer" conservation campaign.For voters interested in change -- and with some good reason -- the roster of challengers is thin.Timothy Nold, 40, a Fort Worth surveyor, criticizes the board for not posting more public notices about committee meetings where action items are discussed. By the time an item comes to the board's full meeting agenda, directors often vote unanimously without debate.That's true. Directors say they comply with state law, but they could choose to give more public notice and deliberate more openly. They have not.Nold also is critical of no-bid contracts issued by the Trinity River Vision Authority, a separate agency that oversees the Trinity Uptown floodway project near downtown. Henderson and the water district general manager, Jim Oliver, also sit on the authority's board.Two other board challengers seem unprepared.Mary Kelleher, 50, a Tarrant County juvenile court supervisor, seems primarily upset with City Hall over flooding on her east Fort Worth property. She does not seem to know much about the focus or operations of the water agency.Dwayne Herring, 46, a remodeling contractor from rural Tarrant County near Eagle Mountain Lake, is running but has not registered to vote.A fourth challenger, John Austin Basham, 42, a meteorologist from Reno in Parker County, declined to be interviewed for this editorial. He does not live in the district, but his ownership of a 1,300-square-foot lot near Eagle Mountain Lake qualifies him as a candidate.Voters may choose one, two or three directors. The three with the highest number of votes win.The Star-Telegram Editorial Board recommends Vic Henderson, Hal S. Sparks III and Jack R. Stevens for re-election to the Tarrant Regional Water District board.