Costing Low Impact Stormwater Devices

Éva-Terézia Vesely Michael KrausseAndré TaylorEarl Shaver

Institute for Sustainable Water Resources

Windows of Opportunity for Low Impact Design

STORMWATER INFRASTRUCTURE

Age Distribution

Typical Lifetime

REPLACEMENTinfrastructure inertia

lock in effects / path dependency

windows of opportunityto explore alternative design

Assessing Alternative Design Options

A shift in our approach to stormwater management will be easier accepted if proven necessary and feasibile.

Tools:

- Life Cycle Costing

- Life Cycle Assessment

- Cost Benefit Analysis

Life Cycle Costing

Australian and New Zealand Standard (AS/NZS 4536:1999)

Life cycle costing is the process of assessing the cost of a product over its life cycle or portion thereof.

Life cycle cost is the sum of acquisition and ownership costs of an asset over its life cycle from design stage through manufacturing, use, maintenance and disposal.

Life Cycle Costing

Costs and the Phases of the Life Cycle (AS/NZS 4536:1999)

Life Cycle Costing in Use

• Comparisons

• Design improvement

• Cost sharing

• Budgeting

• Financial sustainability

Estimating the Cost Elements

(Emblemsvåg, J. 2003. Life Cycle Costing: Using Activity Based Costing and Monte Carlo Methods to Manage Future Costs and Risks, John Wiley & Sons, New Jersey.)

•Analogy method

•Parametric method

•Engineering method

•Cost Accounting method

Calculation Models

• Deterministic – a single value

• Stochastic – probability distributions

• Fuzzy – linguistic expressions & fuzzy sets

(Boussabaine, A. and Kirkham, R. 2004. Whole Life Costing: Risk and Risk Responses, Blackwell, Oxford.)

The New Zealand Experience

COUNCILS:

• Category 1: “Yet to implement”

• Category 2: “Have some data, but lack resources to extract it”

• Category 3: “Data available but …"

The ARC-MUSIC Initiative

February 2005:

“Life Cycle Costing in the Context of Low Impact Stormwater Design” workshop

New Zealand Life Cycle Costing Project

NZ LCC Project

Steps:

1. Draft and refine the data collection protocol

2. Gather costing data

3. Analyse data and define costing relationships

4. Compare the NZ and Australian datasets

5. Code relationships in MUSIC version 4

6. Report findings of the project

7. Launch MUSIC version 4 and conduct training

LCC Data Collection Form

The Goal: to record NZ cost data in a comprehensive and consistent manner.

LCC Data Collection Form

The form:consistent with the intent and terminology of the AS/NZS 4536:1999.

It covers:A. Description of the stormwater treatment measureB. Key design detailsC. Cost Elements

i.) Acquisitionii.) Routine Maintenanceiii.) Corrective Maintenanceiv.) Decommissioning

D. Document control

LCC Data Collection Form

Cost Elements: - real cost- without GST- in the financial year in which they occurred- C (conceptual cost), E (engineer’s estimate), A (actual cost)

The cost of land is exluded from the acquisition cost (but it is included as a separate question in the form).

It explores:- variation of the routine maintenance costs over the first few years- details on corrective maintenance costs- unusual cost elements and circumstances

Where to from here?

GATHER COSTING DATA

ANALYSE COSTING DATA

NZ LCC MODULE in MUSIC version 4

UPDATE

Acknowledgements

The authors are grateful to stormwater professionals from around New Zealand for sharing their

experience.

Further thanks to all those who participated in the ‘LCC in the context of Low Impact Stormwater

Design’ workshop and to the ARC for initiating and co-ordinating the NZ LCC project.