USING GIS TO LINK COMPREHENSIVE CCTV INSPECTION DATA TO COLLECTION SYSTEM PLANNING AND MANAGEMENT

After being plagued for years by chronic sewerage surcharges and basement back-ups, the City of Columbus, Ohio knew they needed to provide relief to the residents of the Livingston-James neighborhood. To determine the most cost-effective way to solve these persistent problems, the Department of Public Utilities' Division of Sewerage and Drainage (DOSD) retained CDM to perform a detailed study of the wastewater and stormwater infrastructure in the 13-square-mile area. This project included the cleaning and assessment of over 700,000 feet of sewer pipes, ranging in diameter from 8 inches to 66 inches. This assessment entailed the recording of pipe conditions using digital closed caption television (CCTV) cameras as an aid in the evaluating the conditions and the building of a detailed computer model to evaluate proposed solutions. The goal of this project is to identify locations and causes of public and private sources of inflow and infiltration (I/I), structural pipe defects, operation and maintenance (O&M) defects and provide conceptual designs to reduce I/I, improve the sewer system performance and minimize basement flooding.The initial phases of this 2 ½ year project are completed. Only the evaluation and recommendationphases remain. The focus of this paper is to detail a few of the innovative data gathering and application techniques developed and applied to complete this project in an effective and efficientmanner.The initial (data gathering) phases of the project compiled interior sewer still images, CCTV video, complaint and condition databases, rainfall, sewer flow and depth data from gauges and monitors, and additional performance data from derived from computer modeling using PC-SWMM modeling software. All this data was then linked by a comprehensive geographic information system (GIS). This innovative combination of tools is expected to support the City's I/I program long after this assessment is finished.Some of these innovative "tools": software, hardware and field techniques employed or expected tobe employed include:Digital CCTV and cleaning of over 700,000 linear feet (130 miles) of 8" to 66" sanitary sewers and creating a single GIS-linked NASSCO PACP databaseFlow monitoring at over 30 locations and rainfall monitoring at 7 different locationsSWMM modeling with RTK Analysis of all pipes in the areaApplication of Gauge-adjusted Radar Rainfall dataPrivate I/I Investigations: Dye Testing of a large sample of private drains, laterals, downspoutsand foundationsWet-weather quick response investigations with CCTV to understand and visually observe flooding and I/I problems and verify model predictionsManaging all CCTV data on external hard drives for ease of transferal and useProviding the City's sewer maintenance crews with photos and maps of collapsed pipes within hoursof inspectionUsing query tools and GIS to create maps that summarize the types & locations of defects and how sewer defects (roots, cracks, collapses, infiltration) correlate to other system characteristics such as age, complaints, flooding, & I/IUsing a 3D viewing environment to assess the potential impact of mainline HGL on basement backup issuesUsing the database, CCTV Video, GIS Tools, and digital photographs to develop a program to help solve lateral root problemsUsing criticality and pipe ratings to help prioritize future CIP programs such as pipeline rehabilitation and O&M programs such as chemical root control and grease control programsDeveloping decision flow charts to determine the correct future course of action for all pipes within the system