This section explains the steps needed to calculate a life cycle cost for each type of stormwater treatment device that MUSIC can model. This section assumes that a MUSIC model has already been created using the method explained in Creating a Stormwater Treatment Train.
A detailed explanation of each step in MUSIC’s life cycle costing process is provided for Constructed Wetlands. As this process is similar for other types of treatment device, only additional steps and device-specific advice is provided for each of MUSIC’s other treatment device types.
Regardless of the type of treatment device, the first step should be to define the base year for costing (i.e. the date for which all costing results will be relevant to). In most cases, this will be the year that the costing analysis is being done. To define the base year for costing, choose Costing from the Settings menu. The following screen should appear.
Manually adjust the ‘base year for costing’ if necessary.
You can edit the default Real Discount Rate and Annual Inflation Rate values in the Life Cycle Costing Properties dialogue if necessary. For definitions of each of these terms, refer to Introduction To Life Cycle Costing or place the cursor on each term and a brief explanation should appear.
- Note that the choice of real discount rate can make a significant impact on the calculated life cycle cost. Care should be taken when choosing this value.
- For up-to-date values for the ‘real discount rate’ and ‘annual inflation rate’, contact experienced local stormwater asset managers, or agencies that specify discount rates for the urban water industry (e.g. the Essential Services Commission in Victoria and the Independent Pricing and Regulatory Tribunal of New South Wales).
The Span of Analysis entry in MUSIC’s Life Cycle Costing Properties dialogue is only relevant when life cycle costing is to be done for a stormwater treatment train (i.e. for a MUSIC model with more than one treatment device). In this case, it is recommended that the value be set equal to the longest life cycle of any of the treatment devices in the treatment train. As this is usually unknown at this point in the costing analysis process, it is recommended that the value be kept at the default value (i.e. 50 years) and adjusted towards the end of the process, if necessary. For more information, see Stormwater Treatment Trains.