Flooding in Metro Detroit inevitable despite pump outage, consultants say
Detroit — Flooding in Metro Detroit following June rainstorms would've been bad even if pump houses on Detroit's east side had been working properly when the downpour hit, two consultants told the Great Lakes Water Authority board on Wednesday.
The assessment from consultants Ed Hogan of Wade Trim and Dave Hitz of Brown and Caldwell was provided to board members as part of a preliminary update on an internal investigation into rain events on June 25 and 26 that water authority officials have characterized as a "1000-year storm."
Hogan said the initial model results show the basement flooding "was similar to what would have occurred under more ideal circumstances."
"There's no question that the intensity of this rain event, and the duration of the intensity of this rain event was such that there was going to be extensive basement flooding," Hogan added.
Hogan noted the water authority subscribes to two weather forecasting services: Weather Sentry, which augured "a little bit more than an inch" over June 25 and 26 and the National Weather Service Probabilistic Forecast, which predicted 1.6 inches between June 24 and 27.
The rain, he said, was much more than that. The system is designed for 1.8 inches of rain in one hour, but it got six inches in three hours. The rainfall resulted in tens of thousands of flood claims and a presidential disaster declaration.
The presentation comes two days after GLWA's interim CEO Suzanne Coffey gave a tour of the two Detroit pumping stations impacted by outages during the June rain, noting the internal review would examine what took place in the days ahead of the storms and the impact it had on operations.
Hogan, during Wednesday's Zoom meeting, showed that Wayne County flood claims were widespread, in every corner of Detroit, and from the Grosse Pointes to the east to about Dearborn Heights to the west. From Eight Mile to the Detroit River.
"Nobody was spared in that thing," noted John Zech, GLWA's board chair and Wayne County's representative on the board.
The final report is not yet complete and wasn't provided to the board ahead of Wednesday's meeting, prompting some aggravation among members.
"I'm not happy the board was not given the presentation before the meeting," said Brian Baker, Macomb County's representative on the regional six-member board. "That to me is unacceptable. This board needs this information beforehand."
Detroit Water and Sewerage Department Director Gary Brown agreed, and questioned the value of the preliminary update.
"Hopefully in the future the board gets documents beforehand instead of live at the meeting," added Brown, who also is one of two Detroit representatives on the board. "I'm not sure we should be putting information out until it's completely vetted."
Wednesday's meeting was Coffey's first since taking the post. She replaces Sue McCormick who announced her resignation in . The update, Coffey told members, was her attempt at transparency.
More: As GLWA CEO resigns, more details of Detroit pump station outage emerge
The internal probe, once complete, is expected to answer whether there's anything the authority could have done to prevent sewer backups in the June storms and others in the weeks that followed.
The Conner Creek Pumping Station in Detroit faced electrical outages during the June rainstorms leaving enough power for only three of its eight storm pumps to operate.
The Freud pump station was down five of eight pumps when rain hit June 25. The issues there were tied to an outage first reported to have occurred June 23 but later revealed to be June 22. Power wasn't restored to that station until June 30.
GLWA also is conducting an external investigation into how the outages occurred. No timetable for the final report has been given.
The outside investigation, led by attorney Jeffrey Collins and assisted by engineering firms AECOM and Applied Science, will focus on pumping stations, power supply and power redundancy, procedures and employees.