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Legislative Assembly for the ACT: 2003 Week 9 Hansard (28 August) . . Page.. 3442 ..

(3) There were about 3700 individual lengths (manhole to manhole) of sewer main and 1600 house connection branch lines that required emergency maintenance during 2002/2003.

(4) The basis for replacing sewers is customer service level rather than simply economics. Mains are replaced when their condition is responsible for frequent and ongoing interruptions to service and when the service level cannot be improved effectively by repair or some form of routine maintenance.

(5) Currently about 3.5 to 5 km of mains are being found each year that can be said to have reached the end of their useful life on the basis given above (that is, their condition is responsible for frequent and ongoing interruptions to service and the service level cannot be improved effectively by repair or some form of routine maintenance). Sewers in need of replacement have been found widely distributed over the whole system and in all but the newest suburbs. Even in the older areas the mains system is still in reasonable structural condition. Typically only two or three contiguous manhole-to-manhole lengths are replaced at any one time. In any given year lengths of sewer in several different suburbs across Canberra are replaced.

(6) The sewer replacement program is ongoing. Generally any mains that are identified as needing replacement in any one year are put into the following year's program. In cases where replacement is urgent they are added to the work in the program for the current financial year.

(7) Based on current assessments of the sewer network condition and the frequency of repeat service interruptions there are about 25 km (or about 500 manhole to manhole sections) of mains within 5 years of being replaced. One cannot be specific about the location of these mains because they tend to be distributed widely over the system and the assessment of the number or length needing replacement in the future is based on a statistical analysis of trends in the system rather than on an advance list.

(8) Replacement of these sewers will be done under the ongoing program for replacement. This program is designed to keep pace with the replacement needs of the system as described above, and is adjusted from time to time to ensure that a backlog does not develop.

(9) The Department of Urban Services has a stormwater maintenance contract with ActewAGL, which requires the contractor to respond to stormwater issues within a given response time. This contract includes the maintenance and operation of the above ground and below ground stormwater networks and many small dams.

(10) Water from the Urban stormwater network is filtered through gross pollutant traps which remove much of the floating debris and sediment. There is a gross pollutant trap located at the tail of each of the Urban catchments. These gross pollutant traps are inspected and cleaned if required after each rainfall event.

(11) Stormwater pipes are designed and built for a 100 year life, but like most assets the life can be extended if properly maintained. The major sources of pipe damage is tree roots, new construction projects and poor construction practices. Stormwater pipes do not have the corrosive chemicals found in sewage and commonly exceed the design life.

(12) There was not significant development in Canberra until the 1930's, this took place around the City, Reid, Ainslie, Turner, Barton and Kingston areas. Many of the pipes in

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