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Expert says Edenville failure "could have been avoided," cites seepage, insufficient spillway capacity
Summary
William Sturtevant, a dam-safety engineer called as a plaintiffs' expert in Krieger v. EGLE, testified that the Edenville (Wixom Lake) dam failure was preventable and that excessive reservoir pressure, inadequate spillway capacity and internal seepage/piping were principal causes. He reviewed FERC and state materials, HEC‑RAS modeling and the part
William Sturtevant, a professional engineer with decades of dam‑safety experience, told the Michigan Court of Claims on Sept. 16 that the Edenville (Wixom Lake) dam failure "could have been avoided" and that excessive water pressure on the earthen embankment — combined with inadequate spillway capacity and internal seepage — produced the conditions that led to collapse. Sturtevant, the plaintiffs' primary expert at an evidentiary hearing, said he reached that conclusion after reviewing the FERC part 12D files, the dam's probable‑failure‑modes analyses, HEC‑RAS routing models and other engineering reports.
Sturtevant described the engineering mechanism he said caused the failure: rising pore pressures inside the embankment (the phreatic surface) elevated as reservoir levels rose, allowing seepage to mobilize granular embankment material and create internal erosion or "piping." He said that process can lead to progressive loss of material, formation of a sinkhole-like conduit and then a rapid, catastrophic breach — a sequence he characterized as the most likely pathway at Edenville. "My opinion is the failure could have been avoided, with some changes to what happened out on the dam prior to the flood event," Sturtevant said. "There was too much pressure on that dam. It couldn't hold." (William Sturtevant, direct testimony.)
Why it matters: Sturtevant testified that two engineering controls that would have reduced risk were (a) increased spillway capacity to pass larger inflows and (b) lower reservoir levels while permanent repairs were planned and executed. He told the court that operating gates fully and constructing an auxiliary spillway or downstream berms (buttresses) would have reduced loading on the embankment. He also stressed the value of seepage monitoring — piezometers and weirs — and noted the unusual, multi‑foot cyclic swings in piezometer readings he found in the records as evidence of poorly compacted granular zones inside the embankment.
Documentation and methods: Sturtevant said he relied on the FERC records (part 12D inspections and PFMA work), HEC‑RAS unsteady flow analyses, consultant reports and historical construction records. He described the PFMA (probable failure modes analysis) process and testified that the Edenville PFMA identified embankment overtopping and internal seepage/piping as Category‑1 concerns that required further analysis. He also reviewed geotechnical borehole reports, stability analyses and a gate‑operation test report prepared by Spicer Group that concluded gates could not be safely operated by portable a‑frames under emergency conditions. Sturtevant described the significance of the spillway capacity numbers in those documents: the licensed facilities could not pass the inflow design flood the state requires for a high‑hazard dam, he said.
What he recommended (on the record): draw the reservoir down to the sill or run‑of‑river for safe, controlled repair work; make gates fully operable (including using cranes/A‑frames in controlled conditions), and construct engineered downstream buttresses or an auxiliary, low‑velocity spillway to protect the downstream slope. He also urged comprehensive stability, seepage and hydrologic studies prior to returning the reservoir to high pool.
What Sturtevant did not do: he said he did not inspect the site in person for this case; his opinions relied on documentary materials and accepted dam‑safety engineering procedures. He testified that his conclusions were formed after reviewing hundreds of pages of FERC and state materials and after running a methodology consistent with the U.S. Department of Interior and Association of State Dam Safety Officials guidance.
Hearing status: Sturtevant completed direct and cross examination on Sept. 16; later in the day the court heard separate challenges to his testimony and to whether the case should be dismissed as a matter of law. The court did not rule from the bench on those motions at the conclusion of the day's arguments.
Ending: Sturtevant's testimony tied technical files and models to concrete engineering mechanisms — seepage, pore‑pressure rise and overtopping — and framed several near‑term actions the plaintiffs say could have reduced the failure risk. The Court of Claims continues to receive briefing and oral argument on the admissibility of expert testimony and on dispositive motions.
