1 NASHVILLE’S PROGRAM REMOVES 3.6 BILLION GALLONS OF I/I George Kurz, P.E., DEE Gregory Ballard, P.E. (Metro Nashville) Paul Stonecipher, P.E. * Master Sewer Growth Plan * A significant portion of this work was conducted with CTE-AECOM as part of the Nashville Overflow Abatement Program

2 OBJECTIVE of Metro’s Project Demonstrate the significant, positive value and effectiveness of trenchless sewer rehabilitation for infrastructure renewal and environmental protection.

3 I/I & SSO ALTERNATIVES BIGGER IS BETTER (Increase Plant and System Capacity) REHABILITATE AND RECAPTURE (Goal in Nashville is 50% Reduction) MIX OF REHAB, EQUALIZATION, ADDITIONAL CAPACITY

4 1970’s Legacy LEAK – BY – LEAK APPROACH (or find-and-fix) –MANY DEFECTS NOT ADDRESSED –ESTIMATED VOLUME BASED ON “SNAPSHOT” –FLOW “MIGRATION” IGNORED

5 GROUNDWATER MIGRATION ACTIVATES NEW LEAKS LEAK "DRY" DEFECT (POTENTIAL LEAK) REPAIR LEAK

6 FIX THE PROBLEM – DON’T BAND-AID THE SYMPTOM

7 Now: “COST-EFFECTIVE” REHABILITATION SYSTEM APPROACH –ACCOUNTS FOR MIGRATION –VOLUME MEASURED –FLOWS PROJECTED TO DESIGN EVENT –MULTIPLE RAINFALL EVENTS –WET & DRY WEATHER

8 MEASURES OF EFFECTIVENESS Reduction of I/I Reduction of Overflows (and concurrent water quality improvement)

9 NATIONAL TRENDS WERF - study of trends of I/I reduction in 44 utilities: “Unfortunately, none of the information between projects was comparable...”

10 OTHER MAJOR PROGRAMS PROGRAM SYSTEM (miles) FLOW (mgd) REHAB (miles) I/I REDUCTION (% or mgd) Miami-Dade3, (W) 152 mgd Atlanta 1,600 s 139 E180 5 mgd E Birmingham_Jeff Co3, W Jacksonville, FL3, W296 Nashville2, ~9.9mgd W - Web,, s - separate, E - EPA DMR

11 LACK OF INFORMATION Holds our industry back Discourages investment in infrastructure renewal Hinders environmental improvements

12 SUCCESSFUL TRENCHLESS REHABILITATION Based on actual field results in Nashville, TN Largest published database for measured I/I reduction in the US Analyzed 94 miles of rehabilitation (295 miles total - ~ 12% system) I/I cut in half 123 overflows eliminated EPA commends stream improvements

13 27 Areas Analyzed 94 Miles Rehabilitated 50 % + I/I Reduction 1/3 + of Total Work in Nashville RESULTS IN NASHVILLE

14 BEFORE-AFTER PROJECT EVALUATION 50% Reduction

15 NASHVILLE MEASURED RESULTS 3.6 billion gallons I/I eliminated annually 49.6% Annual I/I eliminated 53% 24-hour, 5-year I/I reduction 52.2% Peak-hour, 5-year I/I reduction For the 27 areas (94 miles) analyzed so far:

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17 Nashville Overflow Abatement Program 157 Potential SSO Locations Identified Since 1990 Active Overflow =

18 Nashville Overflow Abatement Program 34 Active Overflows & Watch list Locations (As of January 2005) Active Overflow =

19 Governor’s Ceremony Graphic Courtesy of Tennessee Department of Environment and Conservation

20 EPA & Governor’s Deposting Ceremony November miles “de- posted” Many segments on 303d list removed or no longer attributed to collection system failure

21 STANDARDIZED APPROACH (summary highlights) DESIGN STORM (e.g. 5-YEAR, 24-HOUR EVENT) STATISTICAL CRITERIA FOR QA/QC DEFINE RAINFALL EVENT (e.g. 10 HRS DRY PREV.) USE MAXIMUM NUMBER OF EVENTS IN PERIOD MINIMIZE ANALYST BIAS (SELECTIVITY)

22 STANDARDIZED DESIGN TOTAL SYSTEM APPROACH  GOAL: “CONTAINMENT” FOR FLOWS FROM 5- YEAR, 24-HOUR RAINFALL  POLICY: ALL SERVICE LATERALS CONNECTED TO THE REHABILITATED PIPES WILL BE RENEWED TO THE EASEMENT LINE OR THE PROPERTY LINE ALL MANHOLES CONNECTED TO REHABILITATED PIPES WILL BE RENEWED

23 REHABILITATION IS ASSUMED TO ONLY APPLY TO A FRACTION OF THE SYSTEM SO: We must have a way to identify and select the appropriate – failing parts of the system for rehabilitation. *** Random “Find & Fix” until “enough” I/I has been removed is not a STRATEGY ! ***

24 Strategy for Application of Products is as Important as Product Quality Product Effectiveness is Equal (no leaks where applied) Therefore: Concentrate Effort to Defeat Migration Dry Defects on Video May be Wet Weather Leaks Some Defects May Not be Visible on Video Pipe Segments: “Connect-the-Dots”

25 FLOW MONITORING IS A KEY TOOL Target and prioritize basins Correctly interpret hydraulic conditions Conduct model calibration Monitor post-rehabilitation to verify project effectiveness

26 SYSTEM APPROACH ACCOUNTS FOR MIGRATION VOLUME MEASURED FLOWS PROJECTED TO DESIGN EVENT MULTIPLE RAINFALL EVENTS WET & DRY WEATHER

27 SUCCESSFUL REHAB FACTORS EXTENSIVE FLOW MONITORING LATERAL RENEWAL TO EASEMENT “TARGETING” - LINING SELECTED BY OBSERVED DEFECTS, AGE, PROXIMITY, MIGRATION POTENTIAL, SURFACE WATER PERFORMANCE (AIR) TEST LINE & LATERAL

28 Total System: Pick Priority Area WORK ON THE TOP PRIORITY AREA - - AND KNOCK IT OUT !!!!

29 STRATEGIC GOALS MET I/I REDUCTION SSO REDUCTION STREAM IMPROVEMENT

30 Small City Example Population ~400 Treatment capacity 150,000 gpd CDBG Rehabilitation Project Sewer line slip lining Manhole repair

31 Small City Example

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33 ANALYSIS OF DAILY PLANT FLOWS (Sep 2005 – Nov 2006) average plant flow (gross average of all days) Total plant flow in period ADF - Base Flow (average of 7 lowest consecutive days) I/I in period (Total flow minus base flow for period) 0.295I/I per inch rain (I/I divided by period rainfall) normalized I/I per year (I/I for 365 days for annual average rain)

34 Better Estimate of RDII using cumulative rainfall and incremental increase of influent flow – more realistic projection of I/I and has better correlation factor Typical Plot of daily flow related to daily rainfall – poor correlation factor

35 Module #2 Exercise What are your: »Challenges »Obstacles »Barriers to reducing I/ I?