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City of Ann Arbor SSWWEP - Citizens Advisory Committee Coordination — City of Ann Arbor

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Permanent flow gauges

Posted by Vince Caruso on 7 Oct, 2014
Category: No category

Maybe I’m missing something but as per my past comments at the last meeting and previously, and Judy’s comments here, I would like to see some statement of the need for permanent gauges.

As was agreed in the last meeting by OHM cost have come down greatly for this to the $500 to $800 range with radio data collection long and life batteries.

Preventing the kind of failure we found in the Glendale area with three blocked SS lines could be prevented along with many SS basement flooded.

Gauging could alert the city to problems well before they cause loss of property and hardship, not to mention save the city money. Money that could pay for the gauges many times over I would suspect.

I would have liked to see TOAG comments on this option, and would have expected same if they were in the material they received from this CAC.

Gauging for both SS and SW seem well over due given advancements in the field and use in other communities.

I do understand that some consultants do not like permanent gauging as they can be a major Cash Cow for them but times have changed.

$200,000 for temporary gauges could have installed over 200 permanent gauges just from this contract, and the city has had many similar to this in recent years.

Thanks,
Vince

Comments

Robert Czachorski on 7 Oct, 2014:

Thanks for your comments, Vince

In section A6c of the Executive Summary (posted to Basecamp the other day), the third recommendation is:

"Install a series of permanent meters in critical sanitary sewer system areas to provide a long-term record of sanitary system performance."

I am not sure what type of metering you are describing for $500 - $800.  Perhaps you are referencing stage recorders that might be used for stormwater that don't require going into a sewer environment.  The most common flow meters used for sanitary sewer metering by ISCO, Hach, ADS, etc, tend to cost about $3000 - $5000 each. Open channel flow measurement in a sanitary sewer continues to be one of the most challenging places to make a measurement of flow.

Vince Caruso on 8 Oct, 2014:

Thanks for the note on A6c and for putting it in the ES. Sorry I missed it.

From a previous CAC meeting I mentioned the current cost of flow/level gauges and I thought you concurred on my estimate of $500-$800. Maybe you misunderstood my comment.

Mostly interested in level gauges at this time as they may be more doable and give the most bang for the buck.

I will research the issue further but have good evidence from an ACWG member that these are the amounts he sees on trips to many water related conventions in the state in the recent years and from information found on the web.

Thanks,
Vince

Robert Czachorski on 8 Oct, 2014:

Ok.  Level-only monitoring is far easier and less expensive than "flow" metering, which requires a measurement of the velocity of the flow.  Velocity is the tricky and expensive part.