Mundaring Water Treatment Plant - Questions & Answers
Why is a water treatment plant needed?
The provision of a high standard and up-to-date water treatment plant for the Goldfields and Agricultural Water Supply Scheme (GAWS), which supplies water to over 100,000 people from Mundaring to Kalgoorlie, is a high priority for the Water Corporation.
Mundaring Weir has historically been the main source of water for the GAWS. The Mundaring Weir Catchment is one of the few Hills catchments that have development within its boundaries and as a result there have been problems with aesthetic water qualities (colour, taste and odour) of water from Mundaring Weir over the years.
The proposed water treatment plant is required to treat all water from Mundaring Weir, prior to disinfection, to ensure reliable compliance with the current Australian Drinking Water Guidelines and to keep pace with improving water quality standards.
Disinfection facilities have existed at Mundaring Weir for many years but the water is not filtered yet. Filtration has a major role in maintaining the disinfectant residual throughout the pipe network as it removes the organic matter from the water, which if left in the water causes the chlorine residual to decay quicker. The water treatment plant will introduce the filtration process for all water from Mundaring Weir to ensure drinking water to the current Australian standards.
How much better will the water be as a result of the water treatment plant?
Water will comply with the Australian Drinking Water Guidelines at all times.
Where will the water treatment plant be located?
The water treatment plant will be located at the Department of Environment and Conservation (DEC) Perth Hills District Office & Depot site, situated off Mundaring Weir Road.
Why was this site chosen?
This DEC depot site was chosen as the location for the water treatment plant following an extensive 18-month community consultation process. The decision was based on a Multi Criteria Analysis (MCA) sustainability assessment and the voting preferences of the community, as well as considering other economic, environmental and social criteria.
The community forum site selection process was endorsed by the majority of registered community participants taking part, and the MCA process used by the Water Corporation provided extra rigour to the consultation.
Specifically, the DEC depot site was chosen because the site is already disturbed, it is close to the existing infrastructure and the water treatment plant foot print fitted within the land boundary.
While the DEC depot site was not a unanimous choice, there was broad community and stakeholder support for the site. The general view expressed by many stakeholders and members of the community during the consultation process was that all issues associated with this site could be managed appropriately.
What will the water treatment plant look like?
The water treatment plant project is not yet at a stage where we know what it will look like.
There's a standard process the Water Corporation goes through to decide who will design, build and operate the water treatment plant before the design of the plant can be developed.
As part of this process the Water Corporation will talk with, and listen to, the community to ensure that community views are incorporated into the design wherever possible.
What is the capacity of the proposed water treatment plant?
The water treatment plant will be designed to treat up to 240 megalitres of water per day (MLD), although its initial construction will be for a capacity of 170MLD which will more than meet the current demand of up to 130MLD.
How will waste from the water treatment plant be disposed of?
The Water Corporation will work with the water treatment plant operators to minimise and dispose of process waste collected during the operation of the plant.
All rubbish generated during construction and operations will be placed in approved rubbish facilities and regularly carted away to an approved landfill site.
What chemicals are typically stored at a water treatment plant?
Chemicals required for the treatment process include chlorine, ammonia, caustic soda, florodice acid and alum. Most of these chemicals are currently used to disinfect water at the weir. The existing chemical stores below the weir will be decommissioned when the new water treatment plant is commissioned.
All chemicals will be handled and stored in accordance with national standards and guidelines, which have been developed in accordance with national and state regulations.
What site security arrangements will be in place?
The water treatment plant will be designed with security as a parameter. Storage facilities and sensitive operating facilities will be appropriately located on site within buildings and fences to ensure that the facility is secure. High level security precautions will be used to prevent damage from vandalism, theft and to protect the site.
How will the environmental and societal impacts of a water treatment plant be managed?
The Mundaring water treatment plant has been granted environmental approval by the Federal and State environmental regulators.
The Federal Department of Environment, Water, Heritage and the Arts (DEWHA) determined that the water treatment plant project was not a "Controlled Action" and that it could be managed in a "Particular Manner". This demonstrates DEWHA's confidence that all potential impacts listed under Federal environmental legislation could be managed as proposed by the Water Corporation.
The State Environmental Protection Authority (EPA) determined the project as not requiring formal assessment as it could be managed under Part V of the Environmental Protection Act (Clearing).
In addition to the formal environmental approvals processes, the Mundaring Weir Water Supply Improvement projects undertake extensive monitoring and develop management plans for all potential environmental issues.
A comprehensive environmental management system outlining the management strategies and associated action for the water treatment plant will be developed and undertaken by the Water Corporation incorporating advice from relevant agencies and key stakeholders. It will cover issues such as visual impact, noise, light, traffic, vibration and dust management and monitoring, salinity, site hygiene and fire management.
How will the heritage impacts associated with the water treatment plant site be managed?
The DEC depot site (also known as the Mundaring Weir Forestry Settlement and Portagabra) is not listed on the State Register of Heritage Places, which is maintained by the Heritage Council under the Heritage of Western Australia Act 1990. It is however on the Heritage Council of Western Australia Assessment Program, the local heritage list and the National Trust of Australia (WA) List of Classified Places.
While construction on the DEC depot site would involve some loss of heritage values due to the loss of some or all of the remaining buildings from the former forestry settlement, a heritage management strategy is being developed to address the preservation, relocation (if practicable) and the collection of photographs and drawings of the remaining buildings for archival records.
The Water Corporation recognises the historical significance of the DEC depot site and the conservation of heritage elements at the site is a priority. Plans for the water treatment plant on the DEC depot site will obtain relevant heritage approval before any construction can commence.
What impact will the water treatment plant have on the Mundaring Weir Precinct as a tourism and recreation destination?
As part of the Mundaring Weir Water Supply Improvement project, of which the water treatment plant is one element, the Water Corporation is committed to making the Mundaring Weir Precinct an even better place to visit.
Plans to establish an interpretive facility to provide a link between the new projects and the heritage values of the local area are under way. The Water Corporation is working with key stakeholders and has commissioned a Land Management Study to determine the best option for this facility.
We will also work with the community and stakeholders to identify areas for improvement in the local area. This may range from upgrades to public amenities, footpaths, stairs and roads to improving signage, landscaping and picnic facilities.
The Water Corporation intends for the plant to be sympathetic to the local environment and we will work with the community to ensure that the plant blends with the landscape as much as possible. This may include engaging the services of a landscape architect to design screening options, including vegetation, around the water treatment plant so as to ensure the plant is as unobtrusive as possible. Over time, the visual impact of the plant would diminish as trees and screening bushes establish.
The Water Corporation operates more than 200 water treatment facilities throughout the State and, by necessity, most are located close to the community they serve. Experience shows that water treatment plants generally have minimal community impact.
What will the community consultation process involve?
The Water Corporation will continue to work closely with the community and stakeholders in the planning, development and delivery of the Mundaring Weir Water Supply Improvement Project.
An extensive 18-month community consultation process to determine the best option for the water treatment plant site commenced in 2006 and concluded in 2008. A Community Reference Group was formed throughout this process.
Another Community Reference Group was formed in 2009 and continues to provide advice on the Mundaring Weir Water Supply Improvement Project and its impact on the community and users of Mundaring Weir; and to facilitate feedback to, and seek input from, the community on the Project.
In addition, community input will be sought during the Water Corporation's environmental, social and heritage assessment work for all components of the Mundaring Weir Water Supply Improvement Project. This will ensure that all possible impacts are considered and that management plans are put in place.
Will there be any further opportunity for comment on the water treatment plant proposal?
There are two major approval processes required for the water treatment plant, which include opportunity for members of the public to comment and/or lodge objections. These are environmental approval and the Preliminaries to Works process.
Environmental approvals
The water treatment plant was granted environmental approval by the Federal and State environmental regulators (DEWHA and the EPA) in December 2009. During this process members of the public were given the opportunity to comment and/or lodge objections to the proposals. No appeals were received during the appeals periods.
Preliminaries to Works
The Water Agencies (Powers) Act 1984 (WAPA) defines the water treatment plant as ‘major works’ , and therefore requires that it be subject to the Preliminaries to Works procedures stipulated in Sections 86 to 91 of the WAPA.
During this process a period of at least one month is allowed for lodgment of comments or objections in writing.
Public Notices will be placed in the Government Gazette, The West Australian and Hills Gazette specifying the times when and places at which the plans and proposals may be inspected.
When will construction of the water treatment plant begin and end?
Construction of the water treatment plant will occur between 2011 and 2013.
How else can I have a say from now on?
You can ask questions and make suggestions through a representative of the Community Reference Group (contact details are located on this website) or directly to Water Corporation Community Engagement Officer Jacqui Caldwell on jacqui.caldwell@watercorporation.com.au, 08 9420 3506 or PO Box 100, Leederville WA 6902.