The draining of Lake Dunlap has left shallow muddy water and a muddy bank that was underwater until a partial dam collapse on the south end of the lake on Tuesday morning. Much of the water has drained into the Guadalupe River. The water levels have fallen dramatically.Photo: Billy Calzada, Staff / Staff photographer Daryl Payne, bottom, and Mark Worley work to clear debris from the newly exposed bank of Lake Dunlap on Payne's property on Wednesday afternoon, May 15, 2019. A partial dam collapse on the south end of Lake Dunlap on Tuesday morning has caused much of the lake to drain into the Guadalupe River. The water levels have fallen dramatically with Photo: Billy Calzada, Staff / Staff photographer “Aging structural steel” is believed to have caused equipment to fail at a 91-year-old dam, which prompted Lake Dunlap to drop to alarmingly low levels, the Guadalupe-Blanco River Authority said Thursday evening. The authority said it’s committed to finding a way to replace spill gates at all its aging dams but noted that this depends on its ability to secure funds for the improvements, which will cost millions of dollars.