In 2019, a vertical lift gate failed in Lake Dunlap reservoir, which provides water for Calpine’s 1,029 MW natural gas-fired, combined-cycle Guadalupe Power Plant (Guadalupe). This gate failure caused significant water loss in Lake Dunlap, potentially threatening Guadalupe’s capability to generate power. Weston performed a water intake resiliency analysis to quickly determine whether Lake Dunlap was still a secure source of water for Guadalupe by analyzing reservoir infrastructure, threat of invasive species, and water supply constraints due to drought. To gather the necessary information, Weston conducted interviews; reviewed as-built drawings and drought-management plans; analyzed the intake and pumping station; evaluated the effect of discharge from the nearby wastewater treatment plant; and investigated the effect of invasive Zebra mussels found in Lake Dunlap. The results yielded findings that Lake Dunlap was still a reliable source of water for Guadalupe. Moreover, discoveries made during the analysis, such as anticipated increases in water discharged from the nearby wastewater treatment plant, offset concerns of drought for long-term water security for Guadalupe.