Cardno has completed the flood mitigation strategy for the proposed 415 ha Spring Mountain Precinct master planned urban development. Given the topographic constraints of the site and the incised nature of Spring Mountain Creek, an on-line detention strategy was adopted as opposed to a conventional off-line arrangement. As part of this strategy, three cascading high embankment (6-9 m high) on‐line detention basins, a major sports field and a lake system have been proposed to provide flood control functions. This case study describes the approach used to model and optimise these flood controls based on a linked one and two‐dimensional unsteady flow model (TUFLOW). The paper also discusses the suitability of high embankment on‐line detention basins and the critical hydraulic design considerations, such as the dissipation of outlet velocity through discharge‐control orifices, inlet and screen head losses, pipe blockage and embankment failure. An analysis of embankment failure and pipe blockage assessed the potential failure scenarios to determine the impact on the development and downstream properties. The results demonstrate that with appropriate hydraulic design and risk considerations, high embankment on‐line detention basins can be effective flood controls for incised creek systems.
THis was a poster presentation