Drainage and Basin Failure Impact Modelling for Collinson-Mckinnon Catchment - Edmonton, Cairns.

Abstract

The Collinson-McKinnon catchment is located within the Cairns Regional Council in the locality of Edmonton, approximately 15 km south of the Cairns CBD. The catchment varies from steep, densely vegetated bushland in the upper portion progressively becoming moderate, then flat moving downstream. Development within the catchment is on-going, with rural-residential and residential subdivision in the middle of the catchment and rural agricultural land at the downstream extent. The dominant, constructed features on the floodplain include the Bruce Highway and McKinnon Creek Detention Basin. Water Modelling Solutions was commissioned by Council to develop a suite of hydrological, hydraulic and water quality models to ARR 2019 guidelines to support development of a Drainage Management Plan for the Collinson-McKinnon Catchment and Failure Impact Assessment for McKinnon Creek Detention Basin. This paper explores the application of ARR 2019 for catchments in North Queensland and compares differences in outcomes to ARR 1987. The findings show that the 2019 IFD is lower than the 1987 IFD for rare events but similar for frequent events. The paper also steps through achieving a reduction to zero PAR for McKinnon detention basin despite significant siltation occurring within the basin since construction.