Proterra Group
Sewer Maintenance Hole Survey & Condition Assessment, NSW

Client Name

Wingecarribee Shire Council

Value

$50,000 - $100,000

Service

Asset Management

Duration

2022
The Challenge
Wingecarribee Shire is located in the Southern Highlands of NSW and contains six (6) sewerage schemes located at Bowral, Mittagong, Moss Vale, Berrima, Bundanoon and Robertson. The sewer network comprises approximately 645.5km of sewer mains and 10,934 manholes of varying age and condition. Council required Proterra Group to undertake sewer manhole inspections and condition assessment on identified manholes within the Shire as well as the identification of condition and damage including evidence of inflow and/or infiltration.

The sewer manholes included in this project were identified as having an increased level of risk of inflow and infiltration during flood events. Manholes were also selected where key-level information was missing and, if collected, could improve the accuracy of Council’s asset register.
The Solution
Proterra Group undertook sewer manhole inspections and condition assessment on identified manholes, including survey and identification of condition and damage, as well as evidence of overflow and/or infiltration.
All inspections were undertaken from ground level with colour photographs of the condition provided with attribute data and photos clear enough to show the condition identified for future desktop review.
Information was gathered using Council’s online mapping system, ArcGIS Portal. Proterra Group also managed the delivery of all notification letters where all properties where a manhole inspection was to take place at least 48 hours prior to the intended time of commencing works.

Client Contact

Tim Bell - Coordinator Water Assets

Local Buy Contract

No
Delivery Team
Dan Whitehouse, David Mitchell, Maddy Lee, Matthew Ezzy, Brok Whale
The Benefit
Experienced field inspectors utilised RTK GPS technology for detailed GPS field surveys using the software component Magnetic Field, with our in-house GIS officer consolidating survey data within the ESRI suite. Survey data capture included lid elevation, depth and invert levels in AHD.

For this project, field staff documented defects and identified conditions and damage, including evidence of surcharge, a common issue experienced in the area. The majority of assets were located within private properties, with Proterra Group documenting and providing Council with any comments received from residents.
The Result
Council provided an existing set of incomplete data that was quality checked and updated by Proterra GIS and field officers, this included updating survey points for assets and providing additional asset information, inclusive of, manhole attribute data, recorded features and defects.

Ultimately, Council was provided with a more accurate understanding of how the sewer network was functioning, and up-to-date spatial and condition data that allowed for a more complete dataset. Supplied data will allow Council to accurately model the existing sewer network and identify sections requiring upgrade or attention.
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