The Sacramento Weir opened its gates Jan. 10 to reduce water levels in the Sacramento River, but now those gates may begin closing as early as Monday. Thirty-five of the 48 gates are open. The weir acts as a bridge between West Sacramento and Interstate 5 on Old River Road. Most bridges are over water, but this one is blocked with 1,824 wooden planks — each six feet long, one foot wide and four inches thick.