A Hitchhiker’s Guide to Private I/I: Innovative GIS, Modeling and Field Techniques for Achieving Cost-Effective I/I Reductions from Private Laterals and Sewers

摘要

The Hampton Roads Sanitation District (HRSD) is considering a comprehensive private propertyinfiltration and inflow (I/I) abatement program that will rehabilitate private sewers within thesurrounding cities and counties (Localities) in an effort to eliminate Sanitary Sewer Overflows(SSOs). At the heart of HRSD’s proposed private property program is accurate estimates of theamount of private infrastructure in the system and the associated I/I contribution from theseassets, and cost-effectively prioritizing and performing the rehabilitation work. GIS and Exceltools were built to perform spatial queries and frequency analyses, algorithms were developed topredict the footage of sewer on every private parcel, and an innovative process was developed toestimate the cost effectiveness of the private I/I program. Several pilot projects were initiated toevaluate investigative techniques for private laterals, including an innovative wet weathersimulation test; refine the cost-effectiveness of the program; develop public outreach materials;and establish technical standards for performance of the work.