Dear Shajie, Thank you for sharing this video. This is very informative and useful for design of storm water networks, but based on the outflow controls and upstream flood we can decide the orifice plate size. how can we design size of hydro brake? is there any hydraulic spread sheet or in any hydraulic model? Also time at 13.59 you are talking about volume of storage in network, for modelling purpose HB is integrated with the any design suites? to check storage volume differences? Thanks,