Costing Low Impact Stormwater Devices Éva-Terézia Vesely Michael Krausse André Taylor Earl Shaver Institute for Sustainable Water Resources

Windows of Opportunity for Low Impact Design STORMWATER INFRASTRUCTURE Age Distribution Typical Lifetime REPLACEMENT infrastructure inertia lock in effects / path dependency windows of opportunity to 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 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 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 measure B.Key design details C.Cost Elements i.) Acquisition ii.) Routine Maintenance iii.) Corrective Maintenance iv.) 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.