1. City of McCall Sanitary Sewer I&I Study Community Stewardship for Economic Benefits Nathan Stewart, PE, City Engineer Matt Neukom, PE, Project Manager March 20, 2013

2. Collection System Overview 40 miles of sewer main 13 lift stations 300 million gallon winter storage pond

3. Winter Storage Pond

4. Historical Approach to I&I Reduction $1.8 million spent since 2000 –Sewer main replacement –Manhole repairs –Engineering and analysis No system for tracking success vs. failure of improvements

5. Historic Sewer Flows at WWTP Pipe Manholes Winter Storage Pond Million Gallons City Flow at WWTP Average 2009 to 2011 WWTP Flow

6. 2011…New Staff = New Ideas! City Engineer and Horrocks assigned to problem Goals: –Where is I&I coming from within City? should repairs happen first? –How can we track success of repairs? –How can we do this all on a budget?

8. Example of Inflow

9. Where is I&I Coming from within the City? FIRST!: Need accurate sewer collection mapping, identify lift station catchments THEORY: High flow from lift stations in spring will identify areas where I&I is significant Is this a “practical” approach? –Available, accurate data

10. Approach to Analysis

11. Results Average 2009 to 2011 WWTP Flow, Water Use and I&I

12. Results Result: I&I = 37% of wastewater –Assumptions and accuracy Problems –Costs Electricity ~$2,000/yr O&M is negligible –Capacity Lift station alarms: 5 and 7 WWTP Capacity –Exceeded in study period = 10 days Winter Storage Pond

13. Infiltration Analysis – Spring Water use – monthly Pumped volume – monthly

14. Inflow Analysis - Fall 2009 2010 2011

15. Where is I&I coming from? 41% 43%

16. Next Step: Nighttime Monitoring Nighttime manhole observations Recommendations –Manhole repairs –Explore high flow areas –Future visual survey or camera

17. Looking Ahead Reduce I&I by 50% Gain Treatment Capacity

18. Looking Ahead Increase water use 30 years Match existing flow Peak moves to summer

19. Tracking Success of Repairs Model by hand I&I “Accounting System” –GIS integrated data SCADA pump data Water use Rainfall/snow events Automated data file links Asset management program?

20. City of McCall Sanitary Sewer I&I Reduction - Tasks and Schedule 201220132014 Description Winter Spring Summer Fall Winter Spring Summer Fall Winter Spring Summer Fall Winter 1 Infiltration Survey – Nighttime 2 Inflow Survey - Smoke Test 3Manhole Cover inserts 4Manhole Repair leaks 5 I&I Accounting 6 Identify Sump Pumps 7 Remove Sump Pumps 8 Sewer main/service repairs 9 PACP Ratings (manhole/pipe) Next Steps

21. Questions?