Stormwater Software - MUSIC

Taken from http://www.ecosol.com.au/music.asp


MUSIC Stormwater Management System

Introduction to MUSIC

MUSIC is an acronym for Modelling Software for Urban Stormwater Improvement Conceptualisation. It is a product of the Cooperative Research Centre for Catchment Hydrology (now eWater CRC) and the licensor is Monash University.

MUSIC provides a user-friendly decision support system that enables planners to evaluate conceptual designs of stormwater management systems to meet water quality objectives for their catchment and requirements with respect to water-sensitive urban design.

MUSIC allows complex stormwater management scenarios to be quickly and efficiently created and the results to be viewed using a range of graphical and tabular formats. This reduces the uncertainty surrounding the planning of stormwater management strategies, and may generate substantial cost-savings.

To use MUSIC you need to register and pay a fee (currently $330) to download the software. Training and support is provided by the eWater CRC.

Purpose

MUSIC is designed to simulate urban stormwater systems operating at a range of temporal and spatial scales for catchments from 0.01km2 to 100km2 and modelling time steps ranging from 6 minutes to 24 hours to match the catchment scale.

Target user

MUSIC is designed for urban stormwater engineers, planners, policy staff, consultants as well as state, regional, and local government authorities. An understanding of stormwater management principles and practices is required to use MUSIC.

Application of MUSIC to modelling GPTs

Double clicking a GPT icon within MUSIC produces a popup window that requires the following data to be input:
1. low flow bypass;
2. high flow bypass; and
3. piecewise-linear user-definable transfer functions for the GPT performance in capturing Gross Pollutants (GP), Total Suspended Solids (TSS), Total Phosphorus (TP), and Total Nitrogen (TN). In each case the independent variable is input concentration (mg/l or kg/MI) and the dependent variable is the output concentration.

The GPT inputs are independent of the flow rate, except that there are underflow and overflow limits. Flow below the underflow limit, and flow above the overflow limit, passes through with no change of concentration.

Important consideration for MUSIC user

The validity of the predictions is only as good as the validity of the input data. All GPT performance predictions are subject to uncertainty owing to the stochastic nature of environmental processes, with quantities varying chaotically with time and location. The difficulty in making repeatable measurements is illustrated in the wide range of published test results. This is not surprising considering that there can be significant differences, for example in the:

• catchment type and hydrology;
• weather conditions and events during the testing period;
• sampling regimes – frequency, timing, and location;
• composition of pollutant load;
• nutrient transport mechanisms;
• level of bonding of nutrients to suspended solids
• degradation of accumulated pollutants;
• suspended solid particle size distribution (PSD); and the size and state of the unit (i.e. how well it has been cleaned and maintained).

Consequently, when comparing different GPTs, it is important to understand that the results may have been derived in conditions that vary significantly. There is no industry-wide standard for determining the input values required by MUSIC.

Capture Efficiency of Nutriens (TP and TN)

GPTs capture are designed primarily to capture solid particles but, because they attach to these particles, nutrients are also captured. This is measured in terms of TSS capture efficiency. It follows then that GPTs with the same TSS performance will remove the same level of nutrients as along as all other conditions are the same.

The most comprehensive measurement of GPT nutrient capture in Australia was reported in Walker et. al. 1991, a document referenced in Appendix C3 of the MUSIC development team, CRC for Catchment Hydrology (revised February 2005 for MUSIC v2.1). This documents quotes “approximately 30%” TP removal and also found that although TN removal was erratic during storm events, there was “consistent removal of approximately 13% of TN during dry weather flow conditions”.

The MUSIC input data must be viewed as an overall long-term average – in the short term there are simply too many fluctuations making any conclusions largely meaningless. The long-term pollutant capture performance depends not only on the make and type of GPT but how it is managed and maintained.

If inappropriate pollutant removal practices are used to clean the GPT (such as clamshell or removable basket, where much of the sediment is returned to the unit through draining and then subsequently remobilised), it is obvious that claimed nutrient removal rates will be reduced significantly. This is one of the most significant benefits from using the vacuum method, which ensures that all pollutants are removed form the unit.

Recommendations for MUSIC input values for Ecosol units are provided at the bottom of each product page. Click for RSF 100, RSF 1000 and RSF 4000.