Academic Journal of Architecture and Geotechnical Engineering, 2026, 8(1); doi: 10.25236/AJAGE.2026.080103.
Boyang Zou
School of Civil and Environmental Engineering, The University of New South Wales, Sydney, Australia
Urbanization exacerbates flood risk because of the augmentation of hard surfaces. The study assesses the effects of full urbanization on the small campus runoff contributing to the Village Green at the University of New South Wales (Sydney) and the role of an on-site detention basin in peak flow attenuation. The semi-distributed rainfall-runoff model was developed in the ARR 2019 event-based structure in the HEC-HMS platform, and a 1% AEP, 2-hour duration storms were run using the entire set of ten rainfall temporal pattern ensemble members. Peak increases at the critical rainfall pattern from 6.18 to 16.55 m³/s (with an augmentation of 168%), and time to peak drops from 2.50 to 1.83 hours in the post-development scenario. Using the MDA method, a subsequent staged outlet (600mm orifice, and 5m overflow weir with 1.8m crest) resulted in peak outflow of 5.95m³/s, capitalizing on approximately 18,500 m³ of effective storage, fully restoring peak-flow equity. Detention will prove highly effective at restoring peak-flow equity, but the temporal pattern of rainfall will play a fundamental role in designing the structure.
Urban Hydrology, Rainfall-Runoff Modelling, Detention Basin, Design Storm, HEC-HMS
Boyang Zou. Urban Hydrology Modelling Assignment: HEC-HMS Assessment of Urbanisation and Detention Basin Performance. Academic Journal of Architecture and Geotechnical Engineering (2026), Vol. 8, Issue 1: 20-27. https://doi.org/10.25236/AJAGE.2026.080103.
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