SANITARY SEWER EVALUATION SURVEY (SSES) PLAN Prepared for Hampton Roads Sanitation District December 2008 Revised March 2009 Hampton Roads Sanitation District Table of Contents SSES Plan – March 2009 Submittal TABLE OF CONTENTS TABLE OF CONTENTS..................................................................................................................................................I LIST OF TABLES......................................................................................................................................................... IV LIST OF FIGURES....................................................................................................................................................... IV LIST OF ACRONYMS................................................................................................................................................... V 1. INTRODUCTION.....................................................................................................................................................1-1 1.1 Purpose of the SSES Plan............................................................................................................................1-1 1.2 SSES Plan Approach....................................................................................................................................1-2 2. SANITARY SEWER SYSTEM ANALYSIS..............................................................................................................2-1 2.1 Excluded Sanitary Sewer Assets..................................................................................................................2-1 2.2 Review of Historical Records........................................................................................................................2-1 2.2.1 Review of Available SSES Related Inspections................................................................................2-1 2.2.2 Summary of Past Sanitary Sewer Rehabilitation Efforts...................................................................2-2 2.3 Analysis of Sanitary Sewer System Data......................................................................................................2-2 2.3.1 Sanitary Sewer Overflow (SSO) Analysis .........................................................................................2-3 2.3.2 Pump Run Time Analysis..................................................................................................................2-3 2.3.3 Pump Station Wet Well Levels..........................................................................................................2-5 2.3.4 Infiltration/Inflow Hydrographs ..........................................................................................................2-6 3. SSES SCREENING AND PRIORITIZATION..........................................................................................................3-1 3.1 Material Risk of Failure.................................................................................................................................3-1 3.2 Force Main Screening...................................................................................................................................3-1 3.2.1 Segmentation....................................................................................................................................3-2 3.2.2 Failure History and Likelihood of Failure...........................................................................................3-3 3.2.3 Consequence of Failure....................................................................................................................3-3 Screening Approach .....................................................................................................................................3-4 3.3 Pump Station and Pressure Reducing Station Screening.............................................................................3-5 3.3.1 Screening Approach .........................................................................................................................3-5 3.3.2 Screening Results.............................................................................................................................3-8 3.4 Gravity System Screening ............................................................................................................................3-9 3.5 Preliminary Condition Assessment Report ...................................................................................................3-9 4. SSES FIELD ACTIVITIES.......................................................................................................................................4-1 4.1 Field Investigation Approach ........................................................................................................................4-1 4.1.1 Force Main Condition Assessment – Investigation Approach...........................................................4-2 4.1.2 Pumping Facility Condition Assessment – Investigation Approach ..................................................4-3 Gravity System Condition Assessment – Investigation Approach ................................................................4-4 4.2 Procedures for Condition Assessment Activities ..........................................................................................4-5 4.3 Force Main Condition Assessment ...............................................................................................................4-5 i Hampton Roads Sanitation District Table of Contents SSES Plan – March 2009 Submittal 4.3.1 Condition Assessment of Remaining Force Mains ...........................................................................4-6 4.3.2 Assessment of Force Main Appurtenances ......................................................................................4-6 4.3.3 External Pipe Inspections .................................................................................................................4-6 4.3.4 Cathodic Protection...........................................................................................................................4-6 4.3.5 Force Main Condition Assessment Documentation ..........................................................................4-6 4.4 Pumping Facility Condition Assessment.......................................................................................................4-7 4.4.1 Pumping Facility Condition Rankings ...............................................................................................4-9 4.4.2 Pumping Facility Condition Assessment Form..................................................................................4-9 4.5 Gravity Sewer Condition Assessment.........................................................................................................4-11 4.5.1 Assessment Standards for Gravity Sewer System .........................................................................4-11 4.5.2 Gravity Sewer Asset Identification ..................................................................................................4-13 4.5.3 Manhole Inspections.......................................................................................................................4-13 4.5.4 CCTV Inspections...........................................................................................................................4-16 4.5.5 Smoke/Dye Testing.........................................................................................................................4-16 4.6 Final Condition Assessment Report............................................................................................................4-17 4.6.1 Pumping Facilities...........................................................................................................................4-17 4.6.2 Gravity System ...............................................................................................................................4-18 4.6.3 Force Main System.........................................................................................................................4-18 4.6.4 Rehabilitation Plan..........................................................................................................................4-18 4.7 Find and Fix................................................................................................................................................4-19 4.8 Private Source of Infiltration and Inflow (I/I)................................................................................................4-19 5. SSES PLAN IMPLEMENTATION ...........................................................................................................................5-1 5.1 Preliminary Condition Assessment Report ...................................................................................................5-1 5.2 SSES Field Activities ....................................................................................................................................5-1 5.3 Final Condition Assessment Report..............................................................................................................5-1 5.4 SSES Plan Implementation Schedule...........................................................................................................5-1 APPENDIX A: HRSD SEWER SYSTEM MAPS ......................................................................................................