The official groundbreaking to rebuild the Lake Delhi dam is being held Thursday.
The dam collapsed under pressure from flood waters in July of 2010. The nine-mile long lake drained, sending debris rushing down the Maquoketa River.
The estimated cost of rebuilding the dam is $11.9 million. The state, county, and Lake Delhi residents are chipping in to fund it.
The plans also include a new, larger spillway that is expected to handle future flood waters.