A Sustainable Approach to Single Lot Residential Stormwater Disposal

Robertson, Alister (2018) A Sustainable Approach to Single Lot Residential Stormwater Disposal. [USQ Project]


Urbanisation is a worldwide phenomenon which is accompanied by increased in impervious surface coverings which affects components of the water cycle, such as changed infiltration levels. Since the 1980s there has been a move toward more sustainable stormwater approaches (opposed to previous efficiency-based systems) which are commonly referred to as Water Sensitive Urban Design (WSUD) in Australia. It was identified that a missing element in current literature is a volumetric determination of the impact of urbanisation on the levels of infiltration attributable to single lot residential development and generally, the existing research does not identify the storm magnitudes under consideration.

This project developed eleven (11) duration-based, distributed-routing models to replicate gradually varied flow and precipitation infiltration and range in duration from five (5) minutes to two (2) days. Using up to date rainfall data and temporal patterns the models use a Green-Ampt derivation to quantify infiltration and kinematic equation derivation to model the overland flow and determine peak discharge rates. Each model can replicate nine (9) different storm magnitudes from frequent, twelve exceedances per year (12EY), to rare, one percent annual exceedance probability (1% AEP), rainfall events. The models also consider three (3) soil types and three (3) topographical orientations.

Where a development site is a sand soil type, infiltration should be incorporated into stormwater disposal systems. Where infiltration is not used for this soil, the predeveloped water balance experiences a loss of more than 120m3 /lot/event during a two (2) day, rare storm and for shorter more frequent storms this loss is 7m3 /lot/event. Conversely, the use of forced infiltration where soils have low absorptive capacity results in substantial increases to infiltration, this can be an increase of 2-7m3 /lot/event for relatively frequent events of up to only a few hours long. When extrapolated across a precinct, an enormous alteration to the natural water balance is the ultimate outcome, regardless of soil type.

This research has quantified the potential alteration to the natural water balance of a residential lot, considering the developed and undeveloped conditions. By implementing stormwater disposal systems which utilise a combination of direct discharge and infiltration, to replicate the original water balance of the undeveloped state, stormwater management for single lot residential development can be sustainably achieved.

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Item Type: USQ Project
Item Status: Live Archive
Faculty/School / Institute/Centre: Historic - Faculty of Health, Engineering and Sciences - School of Civil Engineering and Surveying (1 Jul 2013 - 31 Dec 2021)
Supervisors: Baillie, Justine
Qualification: Bachelor of Engineering (Honours) (Civil)
Date Deposited: 30 Aug 2022 05:22
Last Modified: 29 Jun 2023 02:30
Uncontrolled Keywords: stormwater disposal; single lot residential development
URI: https://sear.unisq.edu.au/id/eprint/40697

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