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Next Version of Executive Summary and Project Sheets for CAC Endorsement

Posted by Robert Czachorski on 16 Sep, 2014
Category: No category

Folks,
Attached for your review are the revised executive summary and action plan sheets based on the comments from the CAC at the last meeting on Wednesday September 10. Many changes have made to the documents from the discussion last Wednesday. A few changes to note:
We are asking for your concurrence on Section A of the Executive Summary and the project action plans via Basecamp.  If you are comfortable doing that, please note it here.  If you feel that additional discussion or questions need to be addressed before you can concur with it, please feel free to note that as well.  If additional discussion is needed, we would be happy to address comments here, in a phone call, or at the next CAC meeting.
Take care,
Robert

Comments

Colin Breed on 17 Sep, 2014:

Thanks Robert. I concur with the executive summary as amended.
Colin

Judy Hanway on 23 Sep, 2014:

Robert and fellow CAC members,

I have looked through the Executive Summary v6 and have the following comments/observations/questions:

I think that somewhere in the Introduction (page 2) there should be a statement that the City is responsible for the sanitary and stormwater infrastructure.

Page 3: Item c:  possibly edit the following: "After FDD, during the large storm event that occurred on June 27, 2013, there were no reports of basement backups in the five study areas attributed to the sanitary sewer system." I suggest the following (my changes in Bold): "After FDD, during the large storm event that occurred on June 27, 2013, there were no reports of basement backups attributed to the sanitary sewer system, in the five target areas.

Additionally--in this same section, should there be mention of the installation of backflow check valves? Couldn't that be part of the reason there were less basement backups in 2013 than in 1998, 2000? 

Page 3, item f: I'm still not convinced that the WWTP is adequate considering the expected growth of the City and surrounding townships. I think the report should reflect that not all CAC members agree with everything stated in this report.

Page 4, paragraph that begins " Note that a "Scenario C" was examined..." later in this paragraph there is a sentence that begins "In our evaluation of Scenario C, the extent..." My question is--who is "our"? OHM? Should the sentence read "In OHM's evaluation of ..."?

Page 5 item 5 CAC Comments on the Action Plan... I think there should be a statement that some CAC members remain unconvinced that stormwater surface flooding does not impact sanitary sewer surcharges (despite the staff answer on the Q&A log.

Page 6, "(Note that some other considerations and recommendations suggested during the course of the project are not listed because they were found to be not practical to address..." I think this sentence should say that it was OHM and City staff who made these decisions. The way the sentence is written, it implies the CAC made these decisions.

Cut Sheets:

Appreciate the clarification of "sanitary" in numerous places.
Vince's comments from September 10 seem to be missing, ie: 1. permanent metering on Project A and C. 
2. Monitoring flows going into area of Project B. Also--there was discussion amongst the CAC and City staff about a lot of pipes that converged in Project B and the possible complications this might cause.

-Judy

Charlie Fleetham on 23 Sep, 2014:

Judy - regarding your statement that you are unconvinced that the WWTP capacity is adequate to accomodate future growth, what are your assumptions/facts to support  your comment?  According to the City and OHM projections, the plant will have excess capacity for many years.  I have a similar request regarding your comment about stormwater flooding contributing to santiary sewer surcharges.  The data is not supporting this assertion. As the report will probably contain many differing points of view, I think it is important to include backup data/rationale to support arguments contrary to the data presented to date.  

Robert Czachorski on 24 Sep, 2014:

Thanks for your comments, Judy.  I concur with Charlie's questions above on the comments on page 3 and 5.  We will incorporate the other comments, and we need to have some further discussion and thought into how to handle comments like those on pages 3 and 5. 

One thing that you and the CAC might want to consider with respect to the WWTP capacity is the TOAG's evaluation and comments on the technical work. OHM presented our latest methods and findings to the TOAG last week (this was our 3rd presentation to them in this project), and they concurred with it.  The TOAG specifically concurred with the findings about the WWTP, and in fact noted that the 25 Year Frequency Event is probably conservative for the whole system, i.e. the actual flows reaching the plant would likely be less than was predicted, because large rain events typically show significant spatial variation over an area as large as the City.  For that reason, the total flow from the sanitary system is likely to be lower than what the model predicts.  The TOAG is drafting this comment in their written document. The TOAG is in the process of preparing their written document on their review, which we will share with the CAC once it is ready from the TOAG. 

The CAC might want to consider input like this from the technical experts comprising the TOAG when making comments like you have suggested on page 3.

Take care,
Robert

Robert Czachorski on 3 Oct, 2014:

Folks,

We only received additional comments from Judy, so I have revised the documents based in her input, and I am re-posting them for your review. I have attached the executive summary, a red-line version tracking changes from the previous version, and the Project Cut Sheets. I have outlined the changes below.  We will be looking for your concurrence on these at the CAC meeting next week.  Please let me know if you have any questions or comments.

Summary of revisions:

  1. Judy's input was used to revise the document, with some notes outlined below.
  2. Modified the TOAG findings in Item A2c to reflect the TOAG's recent concurrence. 
  3. Cleaned up the dangling items at the end of the recommendations.  DOM will be discussed at the meeting next week.
  4. On the Project Cut Sheets, Project D, Pittsfield Valley, the text box beneath "observations" was revised slightly to more broadly describe the available options as "storage, relief sewer, sanitary flow source removal, including FDD".

Take care,
Robert

---------------

Notes on Judy's Comments
(Judy's comments in regular font, with my notes are added in bold, italic) 

I have looked through the Executive Summary v6 and have the following comments/observations/questions:

I think that somewhere in the Introduction (page 2) there should be a statement that the City is responsible for the sanitary and stormwater infrastructure.

Done.

Page 3: Item c:  possibly edit the following: "After FDD, during the large storm event that occurred on June 27, 2013, there were no reports of basement backups in the five study areas attributed to the sanitary sewer system." I suggest the following (my changes in Bold): "After FDD, during the large storm event that occurred on June 27, 2013, there were no reports of basement backups attributed to the sanitary sewer system, in the five target areas.

Done

Additionally--in this same section, should there be mention of the installation of backflow check valves? Couldn't that be part of the reason there were less basement backups in 2013 than in 1998, 2000? 

Added the presence of check valves to the document.  As I indicated at the last CAC meeting, they were not likely the reason for less sanitary basement backups in 2013 because the sanitary sewer depths at the meters did not fill the pipes, so the check valves would not have activated.  I indicated this as well in the document. 

Page 3, item f: I'm still not convinced that the WWTP is adequate considering the expected growth of the City and surrounding townships. I think the report should reflect that not all CAC members agree with everything stated in this report.

We will be publishing the TOAG's review and comments on this matter once it is ready. In their draft report, they have concurred with the findings. We will have a discussion at the CAC meeting next week on how to handle comments like this, if you still have them after reviewing the TOAG's report. 

Page 4, paragraph that begins " Note that a "Scenario C" was examined..." later in this paragraph there is a sentence that begins "In our evaluation of Scenario C, the extent..." My question is--who is "our"? OHM? Should the sentence read "In OHM's evaluation of ..."?

Yes.  This has been revised. 

Page 5 item 5 CAC Comments on the Action Plan... I think there should be a statement that some CAC members remain unconvinced that stormwater surface flooding does not impact sanitary sewer surcharges (despite the staff answer on the Q&A log.

Similar to the comment on page 3, we will have a discussion at the CAC meeting next week on how to handle comments like this.

Page 6, "(Note that some other considerations and recommendations suggested during the course of the project are not listed because they were found to be not practical to address..." I think this sentence should say that it was OHM and City staff who made these decisions. The way the sentence is written, it implies the CAC made these decisions.

Done.

Cut Sheets:

Appreciate the clarification of "sanitary" in numerous places.
Vince's comments from September 10 seem to be missing, ie: 1. permanent metering on Project A and C. 
2. Monitoring flows going into area of Project B. Also--there was discussion amongst the CAC and City staff about a lot of pipes that converged in Project B and the possible complications this might cause.
-Judy

Permanent metering was reflected in recommendation 6c. Both projects A and B have additional metering recommended as their first action item. 

Additional metering was not added as an action item for project C, because the metering in 2013 had meters at the downstream end of the problem area right at the location of the observed high depths, so the problem area is well understood and we do not believe that additional metering is needed, as we indicated at the last CAC meeting. However, we have noted the request for additional metering by the CAC on the sheet as a "CAC comment" at the bottom.

Patricia Marten on 7 Oct, 2014:

Looking at the 6 sections, that is $450,000 for more studies.  Wondering about the city staffs' ability to more forward on these changes, which are well spelled out, rather then hire outside help.  

The Upper Mallet's Creek study, produced plans to stop flooding in the SW section of the city, but there's no money to do it right now.  Goes on a list for "later".

The city has just hired a company to study developer sewer hook up fees, for $63-69,000.   
http://www.mlive.com/news/ann-arbor/index.ssf/2014/09/ann_arbors_water_and_sewer_con.html

The amount of money, we're spending on studies seems excessive, maybe it's time to fix a few things... that have been studied.... then go forward, with more studies.  

Robert Czachorski on 7 Oct, 2014:

Thank you for your comment, Pat. A few items to keep in mind:

The Mallets study recommendations would normally get funded from the City's stormwater utility.  The long horizon on completing those Mallet's projects was due to the limited funding in the City's stormwater utility.  Projects recommended from the SSWWEP would get funded from the City's sanitary sewer rates, which is a separate utility fund with a larger annual budget.  I can't recall the numbers, but the City's CIP manager, Deb Gosselin, presented the typical process for funding sanitary projects at the May 14, 2014 CAC meeting. I recall a substantial annual budget that was allocated to performing FDDs, for example, that might be available in the future to fund projects. You might review the video and notes from that meeting on the process.  I remember walking away from the meeting thinking that funding was not an issue for the recommendations that the CAC would make.  The City would have to confirm that and speak to the details. But I do believe that they are planning on putting the 6 projects into the CIP process. Perhaps Nick can confirm this when it is appropriate to do so. 

---------

Regarding performing additional studies, if we knew right now exactly what to build to fix the problems, we would be recommending it. The nature of the issues is such that more information is needed before we can know what to build.  The TOAG has agreed with this conclusion, stating in their report:

"TOAG Members expressed support for conducting additional investigation of the target areas as the prelude to proceeding with design and construction of remedial projects. It was generally agreed that the selection of the appropriate remedial measure (i.e. storage, relief sewers, I/I flow reductions, etc.) should be deferred until more information is obtained to confirm the actual extent and severity of current and anticipated future wet weather system deficiencies in these problem areas."

To make an analogy to a health problem, the patient was not feeling well, and came in for a general physical.  The examination was performed and nothing critical or fatal was found, but a few areas of concern were identified. The Doctor is recommending that the patient see a specialist for some additional tests, before a corrective course of action is recommended.  It would not be prudent to operate right after the physical - some addition scans and tests are needed to diagnose the problem first. 

Hope this helps!

Take care,
Robert

Nick Hutchinson on 7 Oct, 2014:

Pat,

In terms of staff's ability to move forward with these project, in general we try to do as much of our work in house as we can.  We need to factor in timing, staff availability, and staff expertise in determining whether the work is done in house or with a consultant. Either way, it will be closely managed by City staff.

As Robert says above, these six projects are being entered into the current CIP process, and will be evaluated and programmed in comparison to all other projects funded from the Sanitary Sewer Fund. While I can't say for sure where they will end up, the Sanitary Fund is larger than the Storm Fund, and I anticipate they will be programmed for the near future.

Robert's medical analogy is a good one. To put in another way, we don't want to spend a million dollars to fix something that turns out to be a $100,000 problem.

Judy Hanway on 8 Oct, 2014:

Charlie and Robert asked me to elaborate on why I'm unconvinced that the WWTP capacity is adequate to accommodate future growth. To me, it's a matter of common sense. It doesn't make sense that an area can continue to grow and not eventually reach a capacity. Some of my concerns seem to be justified by certain statements in the TOAG report sent out a few days ago:

TOAG Members questioned whether the future growth projections for the City are sufficient to accommodate redevelopment projects which might generate a substantial increase in flows. In particular, the potential for high density projects such as high rise buildings in the downtown area may need to be considered.

There is a lot of building going on in all areas of the city, as well as in the surrounding townships that contribute flow to our WWTP. I know that, as far as the townships are concerned, the amount of sanitary flow is capped at certain levels, but just imagine all the flow that will be coming out of the new graduate dorm the University of Michigan is building. Jennifer Lawson has stated that people are using less water. Well, I don't think we can count on that.

Here is another comment from the TOAG report:

However, it is also true that the rainfall volume and intensity in small portions of the Service Area could be higher than what is predicted for the 25 year event, and this could create some localized problems even though the model predicts that the system could handle a 25 year event. The information that is provided to the public will need to be carefully prepared to ensure that there is an understanding that providing a Sanitary Sewer System with the capability to convey a 25 Year Design Event does not guarantee that surcharging problems will be totally controlled.

And another (my emphasis in bold):

  1. OHM Staff summarized the anticipated future flows to be delivered to the wastewater treatment plant for the two Design Scenarios, and presented information comparing these flows to the plant capacity for both treatment processes and wet weather storage units. TOAG Members acknowledged that the available capacity is expected to be adequate to handle the 25 Year Design Event wet weather flows, although it is recognized that this conclusion is based on a hypothetical wet weather hydrograph which shows that the peak wet weather influent flow rates occur over a fairly short period of time (i.e. < 8 hours). Furthermore, the simulation presumes that the Equalization Basin will be empty at the time of the storm so that all of the storage capacity is in fact available. There is no guarantee that these assumptions are correct, but it is also possible that the peak flows actually received during a 25 Year Event may be lower if the areas receiving the most intense rainfall are far enough from the wastewater plant to allow for peak flow attenuation due to the time of travel.  
Here's a question---what if the areas receiving peak rainfall are close to the WWTP?

Charlie and Robert also asked me to defend my position on stormwater flooding contributing to excessive flow in the sanitary sewers. Following is a quote from the recent TOAG report: 

...large rain events typically show significant spatial variation in rainfall volumes and intensities over an area as large as the Ann Arbor Sanitary Sewer System service area.

We all know that one area of Ann Arbor can receive significant rain, while another area might not receive any rain at all. This would certainly affect the amount of water flooding yards, covering manholes in the streets etc. 

Common sense also tells me that when yards and streets (5 lanes across) are flooded with several inches of water, a lot of that water is draining into the sanitary sewers. In addition, certain neighborhoods that were allowed to be built in wetlands, on top of existing creeks, will have water that drains into the sanitary lines--either through footing drains or cracks in the sanitary sewers.

Jim Osborn on 8 Oct, 2014:

"There is a lot of building going... that contribute flow to our WWTP....all the flow that will be coming out of the new graduate dorm the University of Michigan is building"

The present WWTP is less than 50% used for sanitary sewage flow, perhaps only 33%. The rest is rainwater. There is a lot of room for a few dorm toilets and showers, especially since the chance that these toilets will all be flushed during a heavy rain is small. 

 The WWTP is large enough, we just need to keep rainwater out of it.

I agree with Judy that one aspect of doing just that is managing the storm water system. A flooded street, and especially a yard will saturate the ground and some of this will enter the footing drains and some will enter sewer line cracks. Then Frank's favorite, cover holes.

Footing drains may cover an area of only 20 or 30 feet around a home, but flooded areas work their way into this zone, and anecdotal thoughts do not suffice, we need more data, tied with the other study.

One idea is to place power meters on sump pumps in some homes to see how much they work, and from that, measure their pumping.