The last time Tom Fayram walked on water, Lake Cachuma was just a mud puddle. Today, Cachuma is half full, thanks to this season’s extravagant deluge. But even amid this newfound aquatic abundance, Fayram ​— ​as the county’s official water czar ​— ​might find the ability to walk on water an occupational necessity in the months to come, given the challenges ahead. At Tuesday’s Board of Supervisors meeting, Fayram was gently pummeled for presenting a highly preliminary report on a proposal to allow Santa Barbara County water agencies to secure an additional 12,000 acre-feet a year in state water entitlements.