NORTH QUEENSLAND
THE REINVENTION OF THE AYR DRINKING WATER SUPPLY TO MEET WATER QUALITY AND RESILIENCY BENCHMARKS Nick Wellwood Burdekin Shire Council Cal Paige Burdekin Shire Council Tayla Heuir Burdekin Shire Council Coralie Mannea Burdekin Shire Council
The drinking water for Ayr, Brandon and Alva has been historically supplied via a network of connected Bore Fields since approximately 1966. The treatment train associated with this drinking water has been historically low, while still meeting Australian Drinking Water Quality guidelines, due to the historical quality of the ground water in the Burdekin Delta. In recent times contamination of the drinking water was detected in the Principal Bore Field from external sources, which caused many bores to be switched off to meet drinking water health targets. This also resulted in an unbalanced network from the loss of the bore fields and placed additional network pressure on trunk mains not previously used for distribution from other bore fields in the catchment. The resiliency of the total network was called in to question, including water storage, trunk distribution capacity and future treatment
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trains. This resulted in a reanalysis and modelling subsequent of the total network and staged upgrade of trunk mains, Scada Controls, reservoir storage and pressure balance. Construction of these augmented works for the water supply network is now underway, including the design of future treatment works to future proof drinking water supply for several townships in the Burdekin. The details of the network analysis, design, trunk main route selection, bore field upgrade, control systems and reservoir storage analysis and structural design are outlined in this paper. This is the story of ‘The Reinvention of Ayr Drinking Water Supply’ and the many challenges faced on this journey. Executive Summary The potable drinking water of Ayr, Brandon and Alva has been historically supplied via a network of connected borefields since approximately 1966. The treatment train associated with this drinking water has been historically low while still meeting Australian Drinking Water Guidelines, due to the historical high quality of the groundwater in the Burdekin Delta. In recent times, since April 2018, PFAS was detected in the principal borefield coming from external sources which caused many of the bores within the Nelson’s Borefield to be switched off to meet drinking water health targets. This also resulted in an unbalanced network from the loss of this
ENGINEERING FOR PUBLIC WORKS | DEC 2021
centralised borefield and placed additional network pressure on trunk mains not previously used from other borefields in the catchment. The resiliency of the total network was called into question including water storage, trunk distribution capacity and also the need for future treatment options. This resulted in a reanalysis and modelling and a subsequent total network upgrade of trunk mains, SCADA controls, reservoir storage and also pressure balancing mechanisms. Construction of this augmented works for the water supply is now well underway including the design of a future treatment plant to future proof the drinking water supplies for several townships within the Burdekin Shire local government area. This paper sets out the details of this analysis of the network, design elements, trunk main selection, borefield upgrade, control systems, the reservoir storage and also the future filtration staging to meet drinking water requirements for the Ayr catchment. This is the story of the ‘Reinvention of the Ayr Drinking Water Supply” and the challenges faced on this journey. Introduction The drinking water for Ayr, Brandon, Alva and also the remainder of the Burdekin Shire has been historically provided by a series of connected borefields that connects into the Burdekin Delta Aquifer. They effectively provide a ‘slow sand filtration’ of
