To help ensure the safety of surrounding communities, the Guadalupe-Blanco River Authority (GBRA) in Texas has begun a systematic drawdown of the Guadalupe Valley Lakes. Third-party engineering assessments have determined a drawdown is the only available option for minimizing the risks associated with the aging dams.
GBRA has coordinated with the Texas Parks and Wildlife Department to devise a plan designed to minimize impacts to the environment. The dewatering began at the southern-most lake, Lake Gonzales, on Sept. 16, and continues upstream to Meadow Lake, Lake Placid and Lake McQueeney. The drawdown is expected to take three days per lake, with the dewatering of all lakes completed by the end of September, barring any unforeseen delays.
“Safety is our top priority. We understand this is an unpopular decision, but one that we feel is unavoidable given the dangers associated with these dams,” said GBRA General Manager and Chief Executive Officer Kevin Patteson. “GBRA is committed to working closely with the lake associations and the community to mitigate the impact of this difficult, but necessary decision.”
The dams, which form the recreational lakes along the Guadalupe River and impound water for hydroelectric generation, have surpassed the end of their useful life at more than 90 years old, GBRA says. Despite regular maintenance — including significant repairs to the dams following the floods of 1998 and 2002 — assessment by engineering firm Black & Veatch has indicated the original structural steel components at each of the dams are compromised.
After the spillgate failure at Lake Wood in 2016, Freese and Nichols Inc. identified the cause of the failure and GBRA began emergency repairs to address this issue at other dams. While the failures at Lake Wood and Lake Dunlap were both due to deterioration of original steel components, the failure at Lake Dunlap was attributed to an entirely different issue than the failure at Lake Wood, intensifying concerns surrounding the unpredictability of spillgate failures.
Ensuring the long-term sustainability of the dams is a community endeavor. GBRA is working in partnership with the Guadalupe Valley Lakes lake associations and affected residents, as well as city and county officials, to determine the best course of action for identifying, funding and completing the necessary replacement of the dams.
GBRA was established by the Texas Legislature in 1933 as a water conservation and reclamation district. GBRA provides stewardship for the water resources in its 10-county statutory district.