The Bioretention node allows for the creation of a generic bioretention system, also known as a raingarden (Does not include the creation of tree pits and rooftop raingardens as they have separate respective nodes).
Bioretention systems detain stormwater and utilise multiple layers of soil and vegetation to filter and treat pollutants. The process of detaining stormwater also reduces peak volumes of runoff during high rainfall events. The treated stormwater can be directed to stormwater drainage systems or harvested for reuse.
Bioretentions are recommended in the following usage cases:
- Built as an end-of-line measure (typically requires a GPT or other to filter TSS and GP’s)
Bioretentions can be a high maintenance treatment measure depending on the upstream water quality. They should not be used when the water treated has high levels of sediment and litter, the system will quickly be clogged and cease to effectively function. Additionally, catchments with high flow rates should avoid this measure as the garden bed can be easily eroded. A MUSIC Bioretention node has 31 parameters which can be varied, many of them set to various values by Authority Guidelines. Building an appropriate Bioretention as per Guidelines is quite difficult and checking of parameters by Authority is near impossible. John Connor Online sets parameters as per Authority Guidelines, and only allows inputs within the appropriate values.
|Extended Detention Depth (m)
|A high Extended Detention Depth will flood the plants and kill them.
|Highflow Bypass (L/s)
|This value shows at what level of flow the water gets rediverted. Please note the diversion takes place even if the bio is not full.
|Filter Depth (m)
|Below min filter depth plants may not have enough soil to adequately grow.
|Filter Area (m2)
|This is the area of the filter, where the plants are planted
|Surface Area (m2)
|Same as or larger than the filter area. Surface area is larger depending on how steep the EDD batter is.
|Overflow Weir Width (m)
|For example this his is the perimeter of the overflow pit. This value should be proportional with the surface area. A very low overflow weir width leads to plants being flooded.
|Submerged Zone Depth (m)
|A zone under the outflow which keeps some moisture, to increase plant survivability.
*Min max input table based on typical engineering bounds and may differ depending on local authority rules