FYI
Jennifer Cline, P.E.
City of Molalla
Public Works Director
O: 503.759.0218
F: 503.829.3676
"From: Lee, Rob [mailto:roblee@BrwnCald.com]
Sent: Friday, November 21, 2014 1:34 PM
To: Jennifer Cline
Cc: Phillip Bender; Garrett Edmunds; Heather Penni; Dan Huff; jonpatrick1@live.com; Dan Zinder
Subject: RE: GanttChart_I&I Removal.xlsx
Jennifer,
Flow Meters
Each meter roughly runs about $3500 - $5000. General rule of thumb for I/I prioritization is 15,000 to 25,000 LF per meter, so for 30 miles of pipe we’re talking 7 meters. Since there are some interties and we’ll want flows getting to the WWTP, I think 8 meters is a decent start from a budgetary standpoint. For small diameter lines that surcharge, I would recommend two particular meters for purchase:
· ISCO 2150 AV meter (www.isco.com)
· Sigma 930 or 950 AV meter (www.hachflow.com)
A third company, ADS, has good technology but they are a full-service company. They will sell the equipment for you to own so they can be treated as a manufacturer, but their support after purchase isn’t up to the same level as the above two firms that are purely manufacturers.
· ADS Flow Shark (www.adsenvironmental.com)
Project Schedule
I’ve put together a Gantt Chart (see attached) per your Excel file. However, I made four minor revisions and 1 staffing comment:
1. I’ve updated basin names per version 2 you sent yesterday.
2. I’ve added an activity for MACP/PACP training (standard inspection training). To become officially trained and certified can be expensive and time consuming (depending on the number of staff), but we can provide training and QC oversight that will at least get your staff using the standardized processes without the actual certification.
3. I removed the manhole repairs activity, as the manhole work should be prioritized by the leakiest basins and, depending on the technology used to rehab the pipes, the manholes will be either damaged or replaced during the pipe rehab. So if I/I abatement is performed at the basin level (which is generally the most cost-effective methodology), then waiting on the manhole repairs may be the best option.
4. I added hydraulic/hydrologic modeling to the flow monitoring activity. This won’t delay the final report but will give the City a much clearer idea of where the leakiest basins are as well as if any pipes require upsizing during the peak storms.
5. The schedule is aggressive, depending on City staffing. I’m assuming the City will self-perform the activities.
a. Flow monitoring: 2 people, 20% of their time. Depending on the number of flow monitors, you can install 2 per day and then maintain 4 per day bi-weekly. 2 people per flow metering crew, so 2 people for 2 days every 2 weeks.
b. Manhole inspections: 2 people, 50% of their time. These can be done by a single person but if traffic is an issue, we recommend at least a 2 person crew. 10-12 manholes per day, so per your schedule, that’s 2 people half-time on manhole inspections.
c. CCTV inspections: 2 people, full time.
d. Smoke-testing: 2 people, full time.
Staffing
I haven’t resource loaded your Gantt Chart, but my rough calculations show you’ll keep 2 staff busy 75% of their time on flow monitoring and manhole inspections (Jan to April). During smoke-testing, you’ll need another 2 people busy (July to Sept), and during CCTV, another 2 people (July to Nov). Even if the City can provide almost full-time staff for the I/I program, keep in mind the additional need of ~2 FTE during the July to Sept time frame.
I’ll forward the MACP manual and an example manhole inspection form shortly.
Robert Lee
Brown and Caldwell
T 503.977.6625 | C 503.828.7542
From: Jennifer Cline [mailto:jcline@cityofmolalla.com]
Sent: Thursday, November 20, 2014 12:55 PM
To: Lee, Rob
Cc: Phillip Bender; Garrett Edmunds; Heather Penni; Dan Huff; jonpatrick1@live.com; Dan Zinder
Subject: RE: GanttChart_I&I Removal.xlsx
See my comments below in Red.
Jennifer Cline, P.E.
City of Molalla
Public Works Director
O: 503.759.0218
F: 503.829.3676
From: Lee, Rob [mailto:roblee@BrwnCald.com]
Sent: Thursday, November 20, 2014 8:45 AM
To: Jennifer Cline
Cc: 'Phillip Bender'
Subject: RE: GanttChart_I&I Removal.xlsx
Jennifer,
I’ll get this in MS Project today, but some comments as I’ve reviewed the activities:
1. Flow Meters
a. Can we accelerate the purchase of the flow meters? It’d be better if these can get in the ground by early/mid-January. Yes, I can have Garrett start working on this next week. Do you have 3 or more vendors/manufactures that you prefer we purchase these from? If the purchase is over $10,000 we will need 3 bids plus council approval. I’m not familiar with the costs associated with the flow meters.
b. Unless your staff has the availability to easily accommodate flow monitoring, I wouldn’t recommend keeping them in the ground from April to July. Unless there are unusual flow patterns, non-rainy days during the wet-season (e.g., Jan-Mar) will help characterize the wet-season constant infiltration and you’ll only need a few weeks in the summer to characterize dry weather flows and baseline (365 days-a-year) infiltration. Ok I was thinking, we should collect enough data to show the trend through the wet to dry season. Our system does tend to be flashy with rainy weather events. We could do Dec through April? Please adjust the gantt schedule to reflect change in duration.
c. If meters cannot be procured and installed earlier, I would think the flow monitoring could be deferred until Dec-15 to Mar-16. This will likely only delay the final I/I analysis by a couple-few months anyway.
d. A rain gauge will be essential to correlate flow data with actual rainfall. I believe we have a rain gauge at the WWTP the track our rainfall, I was planning on verifying this otherwise we can purchase a rain gauge for the shop.
2. Smoke-Testing
a. Great that the City’s planning on this – one of the lower-cost activities with potential for good results.
b. If there are suspected cross-connections and the City’s committed to smoke-testing and removing the cross connections prior to next winter, there could be some substantial benefits to deferring the flow metering until next winter. We can discuss this further this afternoon.
3. Manhole Inspections and CCTV
a. While it would be great to get the entire City inspected this coming year, if you are concerned about budget at all, in many cases this work can be prioritized and scheduled according to known I/I issues. If we can get the flow monitors in early enough and do a rough analysis on the data, that’s the best way to prioritize the inspections. In other words, inspect the leakiest and oldest basins first.
§ I recall from our previous discussions, ML_D and ML_F being of high concern, with ML_G being a newer subdivision.
b. I would factor in some time to populate GIS based on the data. Some fields would include:
§ Date Inspected
§ Material and Diameter
§ Structural rating
§ Operational rating
c. For the MH and CCTV work, if the City’s not already utilizing NASSCO (National Association of Sanitary Sewer Companies), I would recommend using NASSCO’s Pipeline Assessment Certification Program (PACP) and Manhole Assessment Certification Program (MACP) so that defects are coded according to an industry standard. This removes some of the subjectivity when comparing past with current inspections as well as between different CCTV operators. Do you have a specific form? There are inspection forms included in the template appendix A, do these forms meet the NACP and MACP codes?
4. Other activities that could be added:
a. Spatial (GIS) development of maintenance issues and causes:
§ Reported problems in the collection system (e.g, FOG, roots, structural issues) and corrective action taken with dates
b. Hydrologic modeling – since DEQ regulates communities per the 5-year 24-hour wet-weather event, and assuming we actually only see this even once every five years, modeling will predict what I/I contribution during that peak event. We can discuss this more, but keeping flows contained (e.g., no predicted overflows under these extreme conditions) will be an important part of any I/I removal plan.
The map looks great. It’ll be important to understand how the system (particularly the intertie between ML and BC_B) actually operates during peak flows, but I think you’ve done a great job with the delineation.
I’m in the field today but back in the office by around the lunch hour. Feel free to call if you want to discuss prior to our meeting today.
Robert Lee
Brown and Caldwell
T 503.977.6625 | C 503.828.7542
From: Jennifer Cline [mailto:jcline@cityofmolalla.com]
Sent: Wednesday, November 19, 2014 7:26 PM
To: Lee, Rob
Cc: 'Phillip Bender'
Subject: GanttChart_I&I Removal.xlsx
This does not include the period to make the repairs necessary. This would most likely be budget over the next 5-10 years depending on severity and ability to include lateral improvements.
Jenn