Tom,

I read this report.  One thing they will do differently when they rebuild the dams is drive steel sheet pilings thru the center of the earth berm the entire length of the dam.  This will prevent static fluidization of the sand particles, which was the primary failure mechanism.  There will also be much more armoring of the wetted faces of the earth berm with rip rap to make it more resistant to erosion from high water and overtopping.  The new flood gates will have > 2X the flow capacity vs. the old flood gates to prevent the lake levels from getting so high.  But, there were also human errors that contributed to the dam failures.  The investigation into these human errors is ongoing.  The final report is due in about 8 months.  Our class action lawsuit is stalled out awaiting this report since it will assign liability.

There is a bill going thru the Michigan State Legislature to provide ~ M$500 for dam safety.  Of that, ~M$300 would be earmarked for repair/replacement of the 4 dams.  The rest of the funds would go towards more rigorous and frequent dam safety inspections and regulations.  The bill is currently stalled out in committee.  If it were to pass in its current form, my property taxes wouldn’t increase by 4X.  But, at the moment, I’m looking out my dining room window at the Tittabawassee River and a mud flat where my lake used to be and waiting for a massive property tax bill next year.  If I were convinced there is going to be a lake again, I would have to spend ~K$19 to replace my dock, steps, and seawall to bring it back to preflood condition.  But, who wants to spend thousands of dollars to have a dock overlooking a mud flat?

Thanks for forwarding the report.

Roger Pihlaja
S/V Dynamic Equilibrium

Sent from Mail<https://go.microsoft.com/fwlink/?LinkId=550986> for Windows

From: Tom Van Heule<mailto:tom.vanheule at intrinsicprograms.com>
Sent: Wednesday, September 22, 2021 6:01 PM
To: The Rhodes 22 Email List<mailto:rhodes22-list at rhodes22.org>
Subject: Re: [Rhodes22-list] Edenville and Sanford Dam Failures

I meant megoalthic...

On Wed, Sep 22, 2021, 5:00 PM Tom Van Heule <
tom.vanheule at intrinsicprograms.com> wrote:

> "we would never build a damn like this today"
>
> How would the monolithic have done it?
>
> A tease,
> Tom
>
> On Wed, Sep 22, 2021, 3:26 PM Lowe, Rob <rlowe at vt.edu> wrote:
>
>> This is mainly addressed to Roger, but some others maybe interested.  As
>> a civil engineer, it certainly is of interest to me.
>>
>> The American Society of Civil Engineers recently release their report on
>> the dam failures at Edenville and Sanford.  A couple of stories on their
>> findings.
>>
>>
>> https://www.asce.org/publications-and-news/civil-engineering-source/civil-engineering-magazine/article/2021/09/static-liquefaction-likely-caused-edenville-dam-failure-report-says
>>
>>
>> https://www.asce.org/publications-and-news/civil-engineering-source/article/2021/09/22/failures-at-edenville-and-sanford-raise-concerns-about-other-us-dams?utm_medium=email&utm_source=rasa_io&PostID=38199516&MessageRunDetailID=6486574554
>>
>> Seems like the plausible root cause was uncompacted sand used in the dam
>> while the specifications called for the sand to be compacted.
>>
>> Non-compacted sand allowed it to liquify when the water pressure on the
>> soil got too high.  A video shows the initial failure.  I had not seen this
>> video until I read this report.  Notice the dam fails from inside the dam
>> and then the water breaks through.  The dam was not overtopped as
>> originally thought.
>>
>> https://www.youtube.com/watch?v=Hc3u_CHVHJ8
>>
>> Some of these earthen dams are over 100 years old and were built before
>> engineers understood the engineering properties of soils.  We would never
>> build a dam like this today.
>>
>> Rob
>>
>>