From: Jennifer Cline
Sent: Tue Sep 01 14:01:22 2015
To: Lee, Rob
Subject: RE: RFP for CCTV question
Importance: Normal
Thank you,
Jennifer Cline, P.E. | Public Works Director
Licensed in OR, WA
117 N Molalla Ave. | PO Box 248 * |Molalla, OR 97038
O: 503.759.0218 | F: 503.829.3676
From: Lee, Rob [mailto:roblee@BrwnCald.com]
Sent: Tuesday, September 01, 2015 1:56 PM
To: Jennifer Cline <jcline@cityofmolalla.com>
Cc: Dan Zinder <dzinder@cityofmolalla.com>
Subject: RE: RFP for CCTV question
Jennifer,
Please see the attached GIS package that includes the CCTV layer.
Let me know if you have any questions. Per our discussions, when I see the RFP, I’ll add in language regarding a contract ceiling and looking for ways to make the package as attractive to bidders as possible. I’ll also forward contact info for a few firms I know to do good inspection work.
Thanks,
Robert Lee
Brown and Caldwell
T 503.977.6625 | C 503.828.7542
From: Lee, Rob
Sent: Monday, August 24, 2015 4:14 PM
To: 'Jennifer Cline'
Cc: Dan Zinder
Subject: RE: RFP for CCTV question
Jennifer,
Here’s a quick summary of the basin prioritization based on the flow meter data
Basin Prioritization for Smoke-Testing
In terms of locations, here are peaking factors (peak flow rate compared to the average flow rate immediately preceding the storm) for the bigger storm on March 15.
· Flow Meter 2, Tolliver – 5x peaking factor
· Flow Meter 3, Pool and Sp’aah – 6x peaking factor
· Flow Meter 4, Grange – 10x peaking factor
· Flow Meter 5, Heintz – 6x peaking factor
· Flow Meter 6, Shirley – 9x peaking factor
· Flow Meter 7, Hwy 213 – 3x peaking factor
· Flow Meter 8, Molalla Ave – 6x peaking factor
The results make sense. The meters higher up in the system (e.g., Grange, Heintz, Shirley, Molalla) will have a flashier response since the flows have a shorter time of concentration to the meters and do not have as much time to attenuate. The meters lower in the system that meter a larger area (e.g., Pool and Sp’aah, Tolliver) have a lower peaking factor.
Based on the results, I would prioritize the following basins for smoke-testing.
1. Flow Meter 4, Grange – 10x peaking factor
2. Flow Meter 6, Shirley – 9x peaking factor
3. Flow Meter 5, Heintz – 6x peaking factor
4. Flow Meter 8, Molalla Ave – 6x peaking factor
5. Flow Meter 3, Pool and Sp’aah – 6x peaking factor
6. Flow Meter 2, Tolliver – 5x peaking factor
7. Flow Meter 7, Hwy 213 – 3x peaking factor
Hwy 213 would be the lowest priority. It has the lowest peaking factor and actually had the lowest amount of sustained rainfall-derived infiltration (i.e., how much the flows elevated even once the rain stopped) of all the meter sites (see attached PDF as an example of how much Grange jumps up and stays up following a storm event).
CCTV
For CCTV, the thinking is not quite the same. While CCTV will identify defects in the sewers and there’s a general correlation between infiltration and age of pipe, CCTV is important to identify O&M defects (e.g., blockages), structural defects (e.g., collapses), or possibly cross-connections with the storm sewers. However, a city starting an inspection program will often start with the highest consequence of failure pipes (i.e., the pipes that will have the worst impacts if they fail). This generally means, in order of priority:
1. The largest pipes (e.g., the TL and BC trunks)
2. The hardest to access pipes (e.g., pipes that are in stream corridors that will be a nightmare to get to if they collapse)
3. Pipes under arterials or major roadways (e.g., Mollala Ave or Hwy 213)
4. For a City with I/I issues like Molalla, then we could start to tackle TL_A, TL_B, and TL_C.
5. Oldest pipes or known problem areas. I recall Garrett telling us he had concerns about BC_A3 and TL_D as well, though these were not easily flow metered so we don’t have data on how much I/I they allow into the system.
We normally recommend a basin-by-basin approach (e.g., inspect all of TL_C before moving to TL_B), but if a city has limited funds, we might prioritize the AC or CSP and skip the PVC in areas. This doesn’t mean the PVC cannot have O&M or structural issues, but we recognize the structural issues are more likely in the older concrete and asbestos cement pipes.
I just received updated GIS layers from Dan, I’ve created a rough figure (attached) that shows the recommendations for inspecting the highest priority sewers. In fact, that’s how I’d write the RFP, to get as much pipe inspected without exceeding a set contract ceiling. However, the figure shows ~70,000 LF. Under today’s CCTV prices, you might not be able to inspect that much if you preclean all the pipe.
See the attached for prices we just received from firms on CCTV’ing 50,000 LF in Newport, OR. CCTV prices per foot (total, includes mobilization, traffic control, cleaning, inspection) range from $1.62 to $2.79 per LF. These prices are quoted to us under a professional services contract, so they are not prevailing wage prices. I’m not sure how that will affect pricing. For our project in Newport, Brown and Caldwell will be reviewing the video, identifying immediate structural or O&M needs, making longer term recommendations, and updating the systematic CCTV program we created for them last year. That will add about $1/LF on top of the CCTV firm’s costs. We could do the same for Molalla, or even provide the methodology for how you might identify those things in-house and we could just perform some spot checking in the field and during the review.
I plan to get all of this with greater detail into that tech memo summary I’m working on. However, I know you needed the recommendations. Let me know if you’d like to discuss over the phone rather than by e-mail.
Robert Lee
Brown and Caldwell
T 503.977.6625 | C 503.828.7542
From: Jennifer Cline [mailto:jcline@cityofmolalla.com]
Sent: Friday, August 21, 2015 11:49 AM
To: Lee, Rob
Cc: Dan Zinder
Subject: RFP for CCTV question
Hi Rob,
Assuming the following:
· CCTV inspection is approximately $1.25 incl. mob & traffic control support,
· the work to be completed totals less than $100,000.00,
· estimating between 70,000-75,000 LF of sewer line to be inspected.
What basins do you recommend to prioritize for the contractor to complete this fiscal year?
Thank you and have a great weekend.
Jennifer Cline, P.E. | Public Works Director
Licensed in OR, WA
117 N Molalla Ave. | PO Box 248 * |Molalla, OR 97038
O: 503.759.0218 | F: 503.829.3676