One child welfare caseworker is a particularly lucky duck this year, having won the grand prize 2012 Chevy Sonic in the 14th annual Duck Race at River Forks Park Saturday. Event organizer Sue Van Volkenburg said it was a fitting end to the race, since the $92,000 raised goes to prevent child abuse and child welfare workers are “on the front lines” of child abuse prevention. The winner’s identity won’t be known until Monday, since the winning ticket was bought by Court Appointed Special Advocates of Douglas County. Director Susan Knight said CASA put the name of a child welfare …