YANKTON, S.D. – A large construction contract has begun in the area below Gavins Point Dam along Lake Yankton. The project is to connect relief wells, which are at the bottom, or “toe” of the dam, that are designed to relieve excess water pressure on the earthen structure. There are 75 relief wells and numerous discharges into Lake Yankton. Of those 75 relief wells, 31 will be connected into three main discharges. This will allow for a more controlled discharge. Once the main discharges are installed, the ground will be backfilled with dirt to cover the discharge pipes and prevent any erosion.