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→Example calculation
===Example calculation===
===Example calculation===
A [[stormwater planter]] with footprint of 8 x 1.5 m is planned to received runoff from an adjacent rooftop. The initial design for the planters includes 750 mm depth of filter medium, 50 mm rock mulch, and a further ponding of 300 mm. The underdrain pipe will be embedded into high performance bedding or similar, with a strip of geotextile over the top to prevent migration of the filter media into the pipe. The lab test states that the medium has a hydraulic conductivity of 25 mm/hr.
<math>Q_{max}=50 mm/hr\times A_{p}\times \left (\frac{\sum d}{d_{m}} \right )\times 3.6 \times 10^{-3}</math>
<math>Q_{max}=25 mm/hr\times 12 m^{2}\times \left (\frac{\1.1 m}{0.75 m} \right )\times 3.6 \times 10^{-3}</math>