At an age when many people are well into retirement, Garry Stone, 74, and Julian Larrouy, 78, have decided it is time to turn over their duties as stewards of what is arguably Nevada's most precious resource - water.Stone retired July 31 after 28 years as the U.S. federal watermaster. Larrouy is in the process of training his replacement as deputy watermaster for the East Fork of the Carson River, a position he's held since 1989.Stone and Larrouy stood on a bridge over the Carson River in the bright October sunshine recently and put their combined 113 years of water …