Asset Management Plan –Kerb and Gutter

Kerb and Gutter

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This Supporting Section should be read in conjunction with Council’s Asset Management Plan, the Asset Management Policy (which sets out Council's philosophy of asset management) and Council’s Asset Management Strategy (which provides Council with a clear direction and goal for managing the community's $1.185 billion (as at June 2010) worth of assets).

The condition of Council’s assets has been audited as part of the asset inspection regime, rated against the asset condition reference sheet and captured in Council’s electronic mapping system. The condition of all Council’s assets is rated from excellent to very poor. The colours on the following map indicate the condition of the asset, as detailed in the below table.

1 Excellent Dark Green

2 Good Green

3 Average Yellow

4 Poor Orange

5 Very Poor Red

Map – Condition The following map indicates the condition of kerb and gutter from excellent to very poor across the Wagga Wagga Local Government Area (LGA) and the table highlights the proportion of the network in each condition.

Excellent 19.9% 125,073m

Good 53.1% 333,875m

Average 22.7% 142,738m

Poor 2.7% 16,809m

Very Poor 1.6% 10,241m

1 Current Asset Base

Kerb and Gutter

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Kerb and Gutter

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Size of the NetworkCouncil’s kerb and gutter network measures approximately 629km and is located throughout the city of Wagga Wagga and in the rural villages of Tarcutta and Uranquinty. The network is made up of:

barrier/semi-barrier kerb

mountable kerb

traffic island kerb

200mm stone kerb and

flat spoon drain (common across intersections)

Challenges of the NetworkOne of the biggest challenges facing this network, much like footpaths, is the damage caused by trees, in particular their roots.

Kerb and gutter which is cracked allows stormwater to ingress the road and footpath and nature strip. This ingress of water can cause structural damage to those assets in close proximity to the kerb and gutter, adding to the liability of each of these other assets.

In addition, the cracks and misalignment can impact on the effective movement of water into the stormwater system. Movement of the kerb and gutter and the subsequent misalignment can also become a trip hazard to members of the community.

Kerb and Gutter

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Condition Ratings Reference Sheet The condition of kerb and gutter is audited against a rating scale which ranges from excellent to very poor. This scale is used as the basis of all assessments of kerb and gutter by Council’s Surveillance Team. The rating scale forms the Condition Rating Reference Sheet below.

2 Condition Assessment

Kerb and Gutter

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Risk and Condition Ratings IndicatorsCouncil also uses Risk and Condition Rating Indicators to determine a prioritised works schedule for the maintenance, renewal and replacement of large asset categories. These indicators are used in addition to the Condition Ratings Reference Sheet to enable further analysis of the worst sections of the asset class.

The Indicators are used to develop an overall Works Schedule Priority Rating for each individual asset or section of an asset.

The first stage considers the risk the condition of the asset poses to the community based on location, road classification and estimated pedestrian and traffic volumes. The following table details the Risk Rating Indicators for the kerb and gutter network.

Kerb and Gutter Risk Rating Indicators - Based on Location and Road Type

Weighting Location

1.2 Commercial Precincts (Central Business District, shopping malls)

1.1 Community Precincts (schools, churches, hospitals, clubs, community centres)

1.0 Residential Areas

Weighting Road Type/Traffic Volume

1.3 Arterial Road or Highway

1.2 Sub Arterial/Regional Road

1.1 Collector/Distributor Road

1.0 Residential Road

The second stage of the process considers the Condition Rating Indicators. The following indicators are considered for each section of kerb and gutter:

cracking

misalignment and

ponding

The more deteriorated a section of kerb and gutter is, the higher the rating for cracking, ponding and misalignment. Each section of kerb and gutter is rated against the Condition Rating Indicators detailed in the below table.

Kerb and Gutter

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Kerb and Gutter Condition Rating Indicators

Score Cracking Misalignment Ponding

1 No cracks No misalignment No ponding

2 Isolated fine cracking Isolated misalignment <5mm

Minor ponding in channel only

3 Block cracking 3-5mm Misalignment 5-15mm up to 30% of length

More significant but in channel

4 Block cracking 20-50% of section

Misalignment 15-50mm over 50%

Ponding encroaching pavement <30%

5 Block cracking more than 50%

Misalignment 50mm over 50%

Significant ponding encroaching pavement >30%

The results of the Risk and Condition Rating Indicators analysis are combined to give an individual section of asset a Works Schedule Priority Rating. For example a section of kerb and gutter could be rated as follows:

Kerb and Gutter XYZ

Condition Rating (CR) 4

Cracking (C) 4

Misalignment (M) 5

Ponding (P) 3

Location (L) 1 (Residential)

Road Type (RT) 1.1 (Collector)

Works Schedule Priority Rating Formula

(CR + C + M + P)L x RT

Works Schedule Priority Rating

(4 + 4 + 5+ 3)1 x 1.1 = 17.6

The Work Schedule Priority Ratings for sections of kerb and gutter are then ranked from highest to lowest to produce prioritised schedule of works for maintenance, replacement and renewal of the network.

Kerb and Gutter

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Intervention LevelsTo guide Council’s response to customer requests a set of reactive triggers has been developed for each asset category. These triggers are called intervention levels and include expected response times. The following tables detail the intervention levels and response times for maintenance of the kerb and gutter networks.

Kerb and Gutter Intervention Levels

Lift <30mm Monitor only

Lift 30 – 100mm Inspected within a week. Corrective action taken within one month.

Lift > 100mm Section of kerb and gutter replaced ASAP (if delays are expected the section should be made safe during the delay period).

Condition Inspection RegimeThe condition and risk of the kerb and gutter network will be assessed simultaneously as part of the Condition Inspection Regime. This inspection will audit the condition of the section of kerb and gutter against the Condition Rating Reference Sheet and also assess the risk based on location and usage. The entire kerb and gutter network will be audited every three years.

The inspections will be in the form of a GPS audit routine for all kerb and gutter in the Wagga Wagga LGA. The inspections for the kerb and gutter network should audit the following:

cracking misalignment and ponding

Ad hoc inspections will be conducted in response to customer requests, on a needs basis and where the asset degrades due to un-foreseen or unusual circumstances, like a storm event. These inspections are done onsite by trained Surveillance Officers and the results are captured in Council’s electronic mapping system (ArcGIS).

Kerb and Gutter

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3 Life Cycle ManagementLife cycle management details how Council plans to manage and operate the asset category at the agreed level of service while minimising life cycle coststhroughout the useful life of the asset.

For most local government assets there are four key phases to the life cycle, namely: acquisition, operation and maintenance, renewal, and disposal.

Costs occur in each phase of the asset life cycle. It is important to attribute these life cycle costs to each phase to allow for effective decision making about how the asset will be managed.

The life cycle costs of assets include:

initial capital investment

operation and maintenance

refurbishment and renewal

administration, overheads and taxes

depreciation

capital use rate charges or rate of return and

disposal of the asset at the end of its useful life

The initial capital or investment cost of a new asset is a significant cost and often dominates the decision as to whether to acquire the asset or expand the infrastructure network. However, it is important to include all the costs associated with each phase of the asset life cycle, including ongoing operation and maintenance, future renewal and disposal.

Kerb and Gutter

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Target Maintenance EventsThere are no target maintenance events associated with the kerb and gutter network annually. The maintenance associated with kerb and gutter is in response to Intervention Levels.

Renewal A detailed work plan for the renewal of the kerb and gutter is developed annually to support this Asset Management Plan. This renewal program is prioritised based on condition and risk.

Disposal Currently, Council includes the cost to dispose of an asset in the unit rate of that asset type. As Council moves towards strategic asset management this cost will be captured separately. The Asset Management Plan will be updated to reflect this change as it occurs across the asset types.

Kerb and Gutter

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4 Level of Service The Asset Management Plan for 2011 has been developed based on data collation, research outcomes and the results of Council’s internal stakeholder engagement process.

The next stage of the process is to ask the community to identify which asset condition is satisfactory to them. This will begin with an extensive community consultation process. The consultation will be in the form of a community survey which will be conducted online, at community gatherings, through focus groups and stakeholder meetings. The survey will use new technology, be based on images and a simple selection process. The outcomes of the consultation will form the foundation for true community engagement to occur in relation to the management of infrastructure across the Wagga Wagga LGA, in particular the development of agreed levels of service, supported by Council and the community.

As Council gathers data from the community about the level of service for each asset category the outcomes will be integrated into the Asset Management Plan.

Until the outcomes of the community engagement are known Council will provide costings to achieve an average condition for each asset category and use this as the satisfactory level of service.

Kerb and Gutter

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5 Financial ConsiderationsThe following graph details the proportion of the kerb and gutter network in each condition.

Council’s current liability in relation to the infrastructure network is the sum of all asset units which have a condition rating of poor and very poor. The current liability of the kerb and gutter network is $13,300,000 (in 2010 dollars). The following table provides the details of the kerb and gutter current liability.

Asset Condition Amount Estimated Cost in 2010 dollars

4 – Poor 16.8km $8,300,000

5 – Very Poor 10.2km $5,000,000

Total Current Liability 27km $13,300,000

Projected Annual Maintenance CostsThe projected annual maintenance budget for the kerb and gutter network is estimated to be $257,400 (in 2010 dollars). It is a first principle estimate and is expected to vary as Council continuously develops its asset management process and strategies. The following table provides further details of the projected estimated costs associated with maintaining the kerb and gutter network.

Kerb and Gutter

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Required Increase to Annual Maintenance Budget perAdditional UnitAs the asset base increases it is important to ensure that the annual maintenance budget also increases. The kerb and gutter maintenance budget should increase by $0.41 per additional lineal metre of kerb and gutter infrastructure.

Kerb and Gutter

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6 Assumptions There are some generic assumptions made in the management of assets in Wagga Wagga City Council, these are found in the Asset Management Plan. In addition, the following assumptions have been made in relation to the kerb and gutter network:

The liability and asset value based on an internal unit rate to replace the asset. The unit rate is subject to variation as it decreases as the quantity of kerb and gutter installed increases.

All kerb and gutter that is replaced will be done so in line with the Engineering Guidelines.