Investigating Urban Stormwater Collection for Potable use; a Feasibility Study for Gloucester, NSW

Kellner, Nicholas (2021) Investigating Urban Stormwater Collection for Potable use; a Feasibility Study for Gloucester, NSW. [USQ Project]

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KELLNER Nicholas dissertation_redacted.pdf

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During the prolonged drought across most of 2018 and 2019, Gloucester’s water supply, the Barrington River ceased flowing. This led the council to source water from another local source via water trucks. Council are currently upgrading existing infrastructure within the network and are looking to investigate other potential alternatives.

Background research of urban stormwater collection indicated that high rates of pollutants within urbanised areas make the collection of stormwater impracticable, with high costs for treatment to drinking water requirements. Most collection schemes target collection for non-potable sources and are centred around larger cities. Pollutants were found in high concentrations with most studies within cities. Wetland treatment presents the most practical and cost-effective option for pollutant treatment. Gaps in literature led to the concept of a feasibility study for collection of urban stormwater for Gloucester, a small rural town on the Mid North Coast of New South Wales for potable use and to assess its feasibility as a whole.

To assess feasibility water samples were collected and tested, catchments were modelled to assess runoff yield and a concept design was completed for a wetland. Stormwater samples were tested for metals, suspend solids and nutrients, testing indicated that pollutants concentrations were within normal to low ranges for typical stormwater.

Assessment of the topography of Gloucester indicated that large scale collection of multiple catchments was difficult, a smaller catchment was chosen based on topography. This catchment was 20Ha and a parametric study was completed using MUSIC software, the study assessed how rainfall, pervious losses and reuse affect the total annual outflow of water. The study found that only rainfall and soil capacity affect total outflow with any significance. The average yield found from the site indicated that approximately 100 megalitres of water can be collected from the site each year, approximately 35% of the Gloucester annual demand. During dry periods up to 10% of the annual demand can be met.

A concept wetland design was completed and sized according to available space and average rainfall values to ensure an amount of stormwater storage within the wetland. The wetland was sized at 6000m2 with a 300m2 sediment basin. The wetland was assessed using MUSIC software for typical pollutant values and average rainfall indicating that reductions through the wetland able to produce pollutant reductions of 90% in total suspended solids and between 50% and 60% for nitrogen and phosphorus removal, these reductions meet water sensitive design requirements and reduce pollutants to approved drinking water requirements.

This study was able to determine that with the right catchment parameters and rainfall values urban stormwater can be a feasible alternative to existing supplies. Water collected from mostly residential areas with pervious areas of mostly clay based soils ensure that the runoff is of suitable quality and with a large enough quantity to provide an alternative.

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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: Nahar, Kamrun
Qualification: Bachelor of Engineering (Civil)
Date Deposited: 03 Jan 2023 03:36
Last Modified: 26 Jun 2023 01:35
Uncontrolled Keywords: drought, stormwater collection, potable, feasibility, catchment, wetland, rainfall, pollutant

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