Modifications to Lake Tanglewood Dam and Spillways: Compliance through Innovation

Lake Tanglewood is located 12 miles southeast of Amarillo, Texas on the Prairie Dog Town Fork of the Red River. The primary safety concern related to Lake Tanglewood Dam is Palo Duro State Park, which is located approximately 10 miles downstream of Lake Tanglewood. Much of the area in the park that is used for camping and other outdoor activities is in the river canyone, and access to and egress from camp sites is provided by roads which may become impassable during floods. A sudden breahing of Lake Tanglewood Dam and the resulting flash flood, would therefore, have a very high potential for causing loss of like in the park.
According to the Texas Natural Resource Conservation Commission (TNRCC) design flood criteris, Lake Tanglewood Dam is classified as as intermediate-sized, high-hazard structure. The TNRCC design flood criteria specifies the percentage of the probable maximum flood (PMF) a structure must pass based on hazard and size classification. The PMF is designed as the flood that can be expected from the most severe combination of meteorological and hydrologic conditions that are possible in the region. The TNRCC criteria stipulates that intermediate-sized, high-hazard structures must safely pass the full PMF even without overtopping.
More than half of the 3,000 square mile watershed above Lake Tanglewood consists of flat upland plateaus with numerous depressions called playas. The playas provide flood storage for the region and do not contribute runoff unless they are filled, which rarely occurs. There are two major dams above Lake Tanglewood, Umbarger Dam on Tierra Blanca Creek and Lake Bivins Dam on Palo Duro Creek. Cont.