Key I/I Reduction Plan Components

Transcription

1 MARCH 24, 2015 Brad D. Werner, P.E. Key I/I Reduction Plan Components Understanding of the Collection System Developing solid Ordinances and Policies Long-Range Plan Development Capital Project Implementation Post-Construction Investigation/Record Keeping/Tracking Financing 1

2 CMOM Definition Capacity, Management, Operations and Maintenance Uses Better manage, operate and maintain collection systems Investigate capacity constrained areas of the collection system Respond to sanitary sewer overflow (SSO events) Wisconsin Department of Natural Resources (WDNR) Administrative Code Chapter NR110 NR Definitions Infiltration "Infiltration" means water other than wastewater that enters a sewerage system (including sewer service connections) from the ground through such sources as defective pipes, pipe joints, connections, or manholes. Infiltration does not include, and is distinguished from, inflow. Inflow Inflow "Inflow" means water other than wastewater that enters a sewerage system (including sewer service connections) from sources such as roof leaders, cellar drains, yard drains, area drains, foundation drains, drains from springs and swampy areas, manhole covers, cross connections between storm sewers and sanitary sewers, catch basins, cooling towers, storm waters, surface runoff, street wash waters, or drainage. Inflow does not include, and is distinguished from, infiltration. 2

3 I & I Reduction Public Sewer vs Laterals Rehab Studies generally indicate Mainline Only: 20-25% I/I Reduction Mainline and laterals to R/W: 25-50% Reduction Mainline and laterals to home: 50-80% Reduction The Gold Standard Precast Manholes with chimney seals PVC Mainline PVC Laterals Sump Pumps / Drain Tile Mini-Storm Laterals The Collection System Basin Approach Time to Break it Down Basin Map Advantage Breakdown Collection System into reasonable sections for evaluation Monitoring and investigation of each basin s flow Rank basins based on I/I contribution Evaluate all sources of I/I Track post construction monitoring and evaluation Refinement of the I/I program, based on results Effective and organized long-range planning Enhanced and more detailed understanding of the collection system 3

4 Monitoring / Investigation Techniques Getting to know and understand your Collection System Interviews Flow Metering Smoke Testing Manholes Inspections Bottle Racks A Bottle Rack can be installed in a manhole to determine if a manhole experiences surcharging 4

5 Monitoring / Investigation Techniques Getting to know and understand your Collection System CCTV Televising Mainline Laterals Lift Stations Monitoring the Pump Run Times on Lift Stations to Track Flows Monitoring / Investigation Techniques continued Dye Flood Testing 5

6 Document Visually 6

7 7

8 Sources of Inflow/Infiltration Public System Mainline Joints Fractured Pipe Root Penetration Lateral Connections Sources of Inflow/Infiltration continued 8

9 Sources of Inflow/Infiltration continued Sources of Inflow/Infiltration continued Public System Manholes Castings Adjusting Rings Block/Brick Failures Leaking Barrel Joints Pipe Connections 9

10 MH A5-743 CASTING ROAD ADJUSTING RING BLOCKS IN CONE SECTION SHIFTED BENCH MH A5-707 HOLE IN STREET NEXT TO CASTING CASTING AT ROAD MORTAR UNDER CASTING DETERIORATING BENCH 10

11 Sources of Inflow/Infiltration continued Public System Clearwater Sources in the Right-of-way High groundwater table Sanitary sewer trench acts as French drain Usually lowest utility Water follows the trench Leaking water mains and services Exfiltration from storm sewer Sources of Inflow/Infiltration continued Private System - Laterals Joints Fractured Pipe Root Intrusion Broken Riser Rolled Gasket Pulled Joint 11

12 Sources of Inflow/Infiltration continued Private System Clearwater Sources on the Private Side Groundwater table Lateral trench acts as French drain Leaking water service No drain tile Direct or indirect connection to drain tile, No sump pump Sump pump connection to sanitary Poor surface drainage away from home Clearwater entering basement, then to the floor drain Sources of Inflow/Infiltration continued 12

13 Sources of Inflow/Infiltration continued Sources of Inflow/Infiltration continued 13

14 Sources of Inflow/Infiltration continued Back to the Basin Map Organize Data Visually GIS Advantages Layering your data Fine Tune Your Game Plan Predict the Potential for Success Develop Capital Improvement Plan 14

15 Back to the Basin Map 15

16 Ordinance and Policy Development Review of Existing Ordinance and Policies Definitions Lateral ownership/maintenance/ replacement responsibility Home to Mainline Home to R/W or Easement Acceptable pipe materials Mainline PVC, Clay, Concrete, ABS Truss, Ductile Iron Laterals PVC, Clay, Concrete, ABS Truss, Transite, Cast Iron Ordinance and Policy Development Review of Existing Ordinance and Policies Definitions Defective determination Pipe material Evidence of leaking Roots Mineral deposits Slope 16

17 Ordinance and Policy Development Replacement Ordinance / Policy Laterals Replacement order Cost Share Lateral in R/W Lateral on Private Property Limits of Lateral Reconstruction Assessment Policy Private Project Utility Assistance Ordinance and Policy Development Non-Sanitary Sewer-Related I/I Reduction Projects Sump Pumps / Drain Tile Inventory homes for working sump pump / drain tile Identify / eliminate cross-connections Require sump pump installations Require drain tile installation Annual inspection program Mini-Storm Sewer Program Provide mini-storm for sump pump discharge Assessment policy Long-range plan 17

18 Remediation Techniques for Private Services Conventional Reconstruction ADVANTAGES Proper slope Remove dips and straighten alignment Change pipe size Pipe joints and lateral connection at main Uncovers unknown problems Maximizes useful life DISADVANTAGES Expensive restoration cost to homeowner Physical constraints (garage, sheds, patios, decks, etc.) Higher overall cost with restoration Rear yard sewers / easements Sewers in alleys Sliplining Remediation Techniques for Private Services ADVANTAGES DISADVANTAGES Less restoration costs Pipe can be Schedule 40 PVC Pipe joints and lateral connection at main Rehabilitate under physical constraints Pipe size must be reduced Dips and sags remain Can not traverse bends or sudden alignment changes 18

19 Remediation Techniques for Private Services Pipe Bursting ADVANTAGES Less restoration costs Pipe joints Size option Ability to traverse bends and other alignment changes Rehabilitate under physical constraints DISADVANTAGES Dips and sags remain Remediation Techniques for Private Services Cured-In-Place Liner ADVANTAGES Less restoration costs No joints Ability to traverse bends and other alignment changes Rehabilitate under physical constraints DISADVANTAGES Connections to main Dips and sags remain Reduced effective pipe size Cost is generally substantially higher than sliplining or bursting 19

20 Private Laterals Public Projects Private Lateral Work Bid Under Municipal Contract Homeowners Notified of Non-compliant Laterals Homeowner Given 2 Options Hire their own contractor Complete under Municipal Contract Waiver of Special Assessment and Right to Enter Property 98% Participation Under Municipal Contract Private Laterals Public Projects Homeowner Advantages Municipal Contract Price Project Management by the Municipality Qualified Contractor Municipal Contract Warranty Municipal Financing Options 20

21 Private Laterals Public Projects Municipal Advantages Project Control Single Contractor vs Multiple More Efficient to Manage and Oversee Most Cost-Effective Project Documentation Records Improves Public Education on I&I Private Laterals Public Projects Post Construction Problems Contractor Defects <5% Sump Pump Runs More Basement Floors and Walls Weeping Water Running on the Basement Floor During Rain Events 21

22 Private Laterals Public Projects Typical Costs Estimated Costs for a Typical 4-inch Lateral in Conjunction with a Municipal Relay Project Lateral portion on Private Property Excavated to an Outside Home Reconnection 35 at $53/L.F. $ 1, Lateral Outside Reconnection $ Estimated Cost $ 2, Lateral portion on Private Property Pipe Burst to Home Reconnection 35 at $11/L.F. $ Lateral Reconnection in Home $ Fernco Connection $ Bend $ Cleanout $ Concrete Floor Patch $ Estimated Cost $ 1, No restoration of turf, landscaping, pavement, structures, etc. is included. Contractor shall compact and level the trench with trench spoils of restoration by the property owner. Associated Remediation Projects Storm Sewer Replacement Sump Pump Installation Mini-Storm Sewer Installation 22

23 Post-Construction Items Flow Monitoring Establish Before / After Flows Investigation of any Unresolved I/I Sources identified during Construction Modification of Long-Range Plan Record Documentation Record Drawings Document I/I Sources Removed Update GIS What We ve Learned Successful I/I Programs require doing the Complete Job Mainline Replacement Lateral Replacement to the Home Address Sump Pumps Storm Sewer / Mini-storm In order to identify problems, you need to be actively looking for problems There are very few Big Ones Band-Aids are not the answer 23

24 What We ve Learned Education Governing Bodies Customers Offer Solutions Post-Project Evaluations Develop a Long-term Cost-effective Program Annual Projects 5 10 year Plan Q A 24