← Back to the list of projects

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

← Back to messages

1.38 -C- Do we have a control meter?

Posted by Lori Byron on 20 Dec, 2013
Category: Category 1 - SSWWEP Questions and Presentations

Frank Burdick’s Log Number: 51
Submitted by: Burdick’s Log, October CAC meeting
Category (1,2,3): 1
Status: Closed
Estimated date to address: N/A

Q.  1.39 CAC October meeting - Do we have a control to other neighborhoods for the 2000 storm?
Q.51. Is there a control for the three graphs OHM put up at the October 29 SSWWE CAC meeting? Robert C. (OHM) said that the whole City can act as a control because the FDDP has not had much impact on the volume of the system citywide. If so, doesn't that contradict the premise of the FDD program--which is to reduce sewer backups and avoid overflows into the Huron? 
 
A.51., CAC October meeting. There is not an “ideal” control meter on a small upstream neighborhood without FDDs. However, the wastewater treatment plant (WWTP) is working as a suitable control district with some limitations. The limitations include changes in the system over the last 13 years such as new development (baseflow), and the fact that the flows at the WWTP may have decreased slightly themselves as a result of FDD.  Because houses with FDD comprise only about 5% of the total houses in the City, the WWTP is functioning as a suitable control, despite these limitations. It should be noted that a decrease in flows at the WWTP as a result of FDD would tend to result in the underestimation of FDD flow removals in the priority neighborhoods, when the WWTP is used as a control.

Comments

Frank Burdick on 22 Feb, 2014:

It the WWTP is used the only real "control" for the sanitary system at large:

1. What impact has the recent / on going snow fall had on the flow to the wwtp especially regarding man hole I/I and other non-FDD source of flow?

2. What can the FDD CAC / CDM tell us at to he frequency of discharges of the existing FDD sump pumps?

The purpose of this inquiry is to help narrow down the impact of  non-sump related i/i.  That is if the sump pumps are not running that frequently during this recent "melt" because of the extreme frozen ground still, is it likely that much of the I/I  ( please forgive my all caps here!) currently flowing to the WWTP, can be quantified as non fdd I/I?

Robert Czachorski on 23 Feb, 2014:

I like the idea of looking at the WWTP flow during the snow melt to see the severity of the I/I. Might it be higher when the streets are ponded? If so, might this be indicative of MH inflow? It will be an interesting check.

It is not entirely clear to me that the sanitary flow during snow melt will be completely devoid of footing flow. I heard the handyman Glen Haege on the radio the other day describing house foundations thawing the soil adjacent to the foundation allowing water to get around the basement. As the snow melts, it creates a negative grade for water flow towards the foundation. This could drive water to footing drains. It might be interesting to ask the CAC to keep an eye on their sump pump run frequency as the snow melts. Maybe CDM could provide some sump metering data during this or past melt events too.
———-

The use of caps is of course ok when it’s proper grammar. I think you know that. The use of sarcasm is disrespectful to the team and a violation of the norms. Please stop the sarcasm. It really is not needed. The entire team is working really hard and starting to come together as a strong team. Sarcastic comments are divisive and counter to the objectives of the CAC.