Union Electric Company d/b/a AmerenUE

The Taum Sauk breach became a pumped-storage accountability test because an automated plant kept adding water while its level instruments understated the real reservoir elevation; because the nominally independent high-level protection was physically set above lower sections of the parapet; because a narrow operating margin and no safe overflow route turned a control error into overtopping of an erosion-sensitive embankment; and because technical causation, utility-management judgment, federal penalty obligations, ratepayer treatment and later reconstruction answer different questions.