Dam Failure Case Study: Sugar Creek Watershed Dam No. L-44 (Oklahoma, 2007)

​​​​​​​In August 2007, tropical depression Erin swept across Oklahoma. In the drainage area above Sugar Creek Watershed Dam No. L-44, it is estimated that over eight inches of rain fell in about six hours causing activation of the earth-cut auxiliary spillway. Flows from the spillway were discharged beyond the toe of the earth embankment but returned after encountering the embankment of County Road 1310 located downstream. This unusual flow condition in combination with failure of the right spillway dike and backwater from debris plugging the culvert under County Road 1310 led to significant erosion of the downstream slope of the dam. Ultimately, the erosion advanced through more than half of the width of the dam embankment crest. Had spillway flows continued much longer, the dam would have failed due to erosion and instability of the remaining embankment material.