B r a z o s R i v e r A u t h o r i t y POSSUM KINGDOM LAKE GATE OPERATIONS

B r a z o s R i v e r A u t h o r i t y Page 2 Morris Sheppard Dam at Possum Kingdom Lake Completed in 1941, the Morris Sheppard dam is 2,700 feet long and 190 feet high. The dam consists of nine crest "roof weir" type gates, each approx. 74 feet long and 13 feet high for the passage of floodwaters. Each gate passes approximately 9,600 cubic feet per second (cfs) of water when open.

B r a z o s R i v e r A u t h o r i t y Page 3 As a water supply lake, the Morris Sheppard dam is designed to hold water up to the top of the dam gates; whereas, a flood control lake would tower as much as 50 feet above the top of the lake’s conservation pool. Built before the days of computerized, electronically- operated hydraulic gates, the bear-trap type gates are operated manually – much as they were when the dam was originally built. Gates are accessed via a catwalk that runs the length of the gate area (top of photo).

B r a z o s R i v e r A u t h o r i t y Page 4 When a gate is open, water flows over the top, falling approx. 190 feet to the river bed below.

B r a z o s R i v e r A u t h o r i t y Page 5 Foam is created by the churning of the water as it reaches the riverbed below. Here the gate is beginning to rise, causing an indention in the flow of water.

B r a z o s R i v e r A u t h o r i t y Page 6 As the gate is raised, the rate the water travels over the dam begins to slow. A stream of water released from a low flow gate may be observed in the background (left).

B r a z o s R i v e r A u t h o r i t y Page 7 When the gate is fully raised, water flow stops.

B r a z o s R i v e r A u t h o r i t y Page 8 To complete the gate closure, a member of the operations team must descend to the top of the gate to lock it in place.

B r a z o s R i v e r A u t h o r i t y Page 9 Since the gates are accessible only via catwalk, the operator must move to the top of the dam gate to manually engage each of the ten locks across the top.

B r a z o s R i v e r A u t h o r i t y Page 10 To ensure the operators’ safety, a body harness is attached to a safety wire running the length of the dam gate.

B r a z o s R i v e r A u t h o r i t y Page 11 By standing on top of the gate, the operator manually accesses the lever locks.

B r a z o s R i v e r A u t h o r i t y Page 12 An operator has to repeat this procedure each time a gate is opened or closed.

B r a z o s R i v e r A u t h o r i t y Page 13 Once each lever is locked, the operator returns to the catwalk on the opposite side of the dam.

B r a z o s R i v e r A u t h o r i t y Page 14