Drivers headed south on Bruce B. Downs Boulevard will need to take an alternate route as they approach Fletcher Avenue as engineers fill a sinkhole that opened in the road Saturday. It was about 12 to 15 feet deep, according to the Sheriff's Office. Vehicles were being diverted from Fletcher to 22nd Street to 131st Avenue, and back to Bruce B. Downs. County and city of Tampa engineers were called to the scene to evaluate the problem and begin repairs, Sheriff's spokesman Lt. Albert Frost said. The cause was not known.