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Pressure from Ofwat and higher customer expectations mean that water companies are raising their game with regard to sewer asset management. John Hateley of Severn Trent Water reveals how linking CCTV data to GIS with InfoWorks helped the utility transform its hydraulic analysis

Pipework at Barnhurst

sewage works

efficiently is GIS. It not only allows them to see the location of their assets – it reveals where they are failing. Ten years ago, GIS was more or less a mystery. It was used mainly by

major software companies, many of whom did not understand their customers’ needs and therefore did not always deliver a useful product. Some companies and councils had such bad experiences with these early systems that they are still wary of GIS.

Drainage plan

Severn Trent Water (STW)’s 2000 Drainage Area Plan (DAP) programme included a major CCTV program, which was expected to produce a considerable quantity of data to be managed. This programme proved a turning point in the company’s use of GIS. It had GIS details of its sewers but nothing that could link the CCTV data to them. Fortuitously, MWHSoft had developed InfoNet and Severn Trent had been using the software purely to hold CCTV data. Now, the company could incorporate it into the data cleansing and validation element of the DAP model build process. This meant InfoWorks could be used for hydraulic analysis. Since then, the company has continued to develop its use of InfoNet. It now holds details of nearly 300,000 surveys, all referenced to the pipe surveyed. This data is used to formulate the company’s June return, asset inventory and price review submissions. When STW is being audited and the auditor requests details on the pipes surveyed during the year, InfoNet can quickly provide a list, a very impressive capability. The Ofwat reporter for STW’s June Return 2008 noted: “The incorporation

of its CCTV into the InfoNet system is commendable. It should enable STW to make use of the benefits of the data produced for Drainage Area Plans.” InfoNet has become more than simply a GIS-based data cleansing tool

and CCTV database; it can also be used as a proactive management tool for company assets. At Severn Trent, InfoNet has been used as part of the Periodic Review 2009 (PR09) process. When shown the data held in InfoNet and the work the company had undertaken to program maintenance, one of the reporters said: “We believe that the company’s use of this software and the further applications that they are investigating for its use, for example maintenance scheduling, is industry leading.”

30 Water & Wastewater Treatment May 2010

Optimising sewer assets


ata underpins water company records and must be gathered accurately and in a form that can easily be turned into usable information. The key to managing these companies’ assets more


The first InfoNet application STW used was the CCTV tool. The company has a CCTV framework that uses InfoNet for data management. Once it identifies the pipes to be examined, it simply emails the contractors an InfoNet Snapshot file of the sewer records and the pipes to be surveyed. The contractors send their survey data back in the same format. The data is validated and stored in a central repository. In AMP4, STW surveyed over 6,000km of sewers, with one person managing the entire process in-house. The company has built on this early work. Over the past two years, it has

begun to manage its proactive cleansing and rehabilitation program in the same way. This effort aims to reduce the number of pollution and internal flooding incidents by reducing the number of blockages and collapses. Sewers with the highest risk of creating pollution or internal flooding are identified and prioritized. Contractors are then given a list of these sewers in InfoNet Snapshot format. When the contractors survey the sewers, they record the condition, undertake cleansing if necessary, and report the condition after treatment. The company knows the exact condition of its assets before it intervenes as well as the condition after the intervention, with all data recorded in InfoNet. This enables the company not only to measure the improvements made, but determine which areas need to be re-cleansed. The structural condition of the sewers is also assessed, and a

Rolando Justa, managing director of Herrenknecht Mexico

rehabilitation programme is produced and managed in the same way. Finally, InfoNet is central to the process of enabling Severn Trent to keep track of its contractors’ work and its cost.

Future intervention

In AMP5 (2010-2015), the company aims to take its activities one step further, using InfoNet to assist with the intervention decision-making process. The software uses SQL to analyze CCTV surveys and chooses the appropriate intervention type, whether a local repair or full-length rehabilitation, based on the defects found. MWHSoft has ensured that many features the industry will need in the

future are already part of InfoNet, particularly scheduling, pipe repair and cleansing tools. Further enhancements are in the pipeline. One recent development is flow and depth monitoring. InfoNet has always been able to hold Time Varying Data, but STW has not needed it. However, going forward, flow and depth monitoring will be an increasingly important part of pollution strategies. These processes will produce a great Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56  |  Page 57  |  Page 58  |  Page 59  |  Page 60  |  Page 61  |  Page 62  |  Page 63  |  Page 64