4: Context

• 4.1 Statutory and Management Plans
  • 4.1.1 National Capital Plan
  • 4.1.2 The Lake Burley Griffin Management Plan 1995
• 4.2 National Water Quality Guidelines
• 4.3 Existing Management Practices
• 4.4 Recent Incidences of Elevated Bacterial Levels
  • 4.4.1 Responses During Elevated Bacterial Counts

The context in which the Water Quality Management Plan (WQMP) has been prepared includes:

• requirements to manage the water quality of the Lake with the aspirations of the statutory plans such as the National Capital Plan and the Lake Burley Griffin Management Plan relating to the Lake and to water quality generally;
• compliance under the National Water Quality Management Strategy (NWQMS), and ANZECC/ARMCANZ (2000), for establishing quality standards, monitoring water quality and reporting pollution incidents;
• existing Lake management practices; and
• recent reported incidences of elevated levels of bacterial activity in the Lake and concern about the health consequences and impacts on Lake-based recreational events.

4.1 Statutory and Management Plans

4.1.1 National Capital Plan

Water quality management is identified as an important management issue in the National Capital Plan. Broader water quality objectives of the NCP are generally consistent with the National Water Quality Management Strategy guidelines, and they are covered in Section 1.2 of the NCP, a copy of which can be obtained from the Authority's Web page at www.nationalcapital.gov.au.

The object of the NCP is to ensure 'that Canberra and the Territory are planned and developed in accordance with their national significance'. Lake Burley Griffin is defined in the NCP as part of the Central National Area. It is a Designated Area under the provisions of the Australian Capital Territory (Planning and Land Management) Act 1988, being an area having the special characteristics of the National Capital.

A most significant aspect of the NCP is the National Capital Open Space System (NCOSS), which exists to protect the nationally significant open-space framework, visual backdrop, and landscape setting for the National Capital. The management of water resources as a part of NCOSS comes under two categories:

1. The Murrumbidgee and Molonglo River Corridors; and
2. Lake Burley Griffin

The land use policies associated with the above water resources allow certain functions, such as nature conservation and recreation, along the foreshores and river corridors (ie places where water quality is an important management issue).

4.1.2 The Lake Burley Griffin Management Plan 1995

In relation to the management of the Lake, the National Capital Plan (NCP) recommended the preparation of a management plan for the Lake (Appendix J of the NCP).

The Lake Burley Griffin Management Plan was developed in 1995 (LBGMP1995) through extensive public consultation. The broader objectives of the water quality management of the Lake were derived from this plan which specifically identified the following key requirements:

• Promoting the ornamental and visual values of the Lake as intended by the NCP.
• Maintaining the Lake as a viable and stable ecosystem, which encourages the development of plant and animal species in order to protect the ecological, aesthetic and scientific values of the Lake and its foreshores.
• Having an acceptable "quality of flow" regime that enables the Lake to be utilised as a water quality control pond to maintain, as far as practicable, downstream water quality and flow.
• Maintaining acceptable water quality to support the recreational and commercial functions of the Lake.

Broader aspects of the management issues are covered in the LBGMP1995, many of which can be related to this Water Quality Management Plan (WQMP). This WQMP should consequently be read in conjunction with the LBGMP1995.

In terms of water quality monitoring, the LBGMP1995 recommends the following:

Types of Water Quality Programs

The LBGMP1995 identified the types of water quality programs necessary to address water quality issues as:

• Monitoring for baseline performance to determine how the water quality of the Lake is performing against management objectives or guidelines, and establishing long term goals.
• Monitoring for specific periods at specific sites from a public health and safety viewpoint, particularly in relation to primary and secondary contact recreation.
• Intense monitoring for specific events or specific parts of the Lake with a view to improving the understanding of Lake process.

The Zoning of the Lake for Activities

The LBGMP1995 directs the management of water quality to be based on a 'best practicable means' approach aimed at satisfactory water quality objectives for different parts of the Lake in accordance with designated water use. The designated uses of different parts of the Lake have been derived from the water quality considerations and they limit the nature of the recreational activities permitted in a particular area.

Based on water quality considerations, the Lake is divided into five regions:

• Molonglo Reach. This is the section of the Molonglo River from Dairy Road to East Basin Pavilion. Zoned for primary contact water recreation activities.
• East Basin. This extends from Molonglo Reach to Kings Avenue Bridge. Secondary contact water sports only are permitted here. This section of the Lake is relatively shallow, so it is subject to high turbidity in windy conditions and has poorer water quality than other parts of the Lake. Wall structures are in place around much of this area to discourage incidental primary contact with the water.
• Central Basin. This is the section between Kings Avenue and Commonwealth Avenue. It is a secondary contact area, and normally reserved for water activities where the emphasis is on passive recreational use.
• West Lake and Tarcoola Reach. This is the area from Commonwealth Avenue to Kurrajong Point, and is the principal recreational area of the Lake, supporting both primary and secondary contact water sports.
• Yarramundi Reach. This section supports rowing events and other water spectator sports and is zoned for secondary contact but primary contact is also permitted.

The above framework forms the basis of the Authority's current Water Quality Program with the necessary enhancements added over the period since the LBGMP1995 was prepared. The monitoring programs are designed to support the Lake's activities, including public health and environmental management considerations as well as the monitoring of the on-going performance of water quality.

4.2 National Water Quality Guidelines

This Water Quality Management Plan (WQMP) is based on the National Water Quality Management Strategy guidelines, entitled Australian and New Zealand Guidelines for Fresh and Marine Water Quality (2000) (ANZECC/ARMCANZ, 2000).

The Guidelines provide an authoritative template for setting up water quality objectives and limiting values for all Australian waters.

These Guidelines were prepared according to the National Water Quality Management Strategy (NWQMS) and are aimed at helping the community, catchment managers, and water authorities protect water quality.

The Lake Burley Griffin Management Plan 1995 identified a number of broader principal values for the Lake to reflect management objectives of that plan. From those values, several environmental values have been derived for the purpose of this WQMP.The applications of ANZECC/ARMCANZ (2000) for each of these environmental values are shown below:

Recreational Water Quality Criteria

The philosophical approach of ANZECC/ARMCANZ (2000) generally recommends a risk-based assessment for decision-making for water quality objectives, depending on local environmental conditions.

A planned update of ANZECC/ARMCANZ (2000) will incorporate the outcomes of the review of recreational water quality health criteria by the National Health and Medical Research Council (NHMRC).

The NHMRC is currently revising its current guidelines on recreational use of water, based on the recommendations contained in World Health Organisation (WHO) Draft Guidelines for Safe Recreational Water Environment: Coastal and Fresh-water (1998) which adopts a strong risk-based approach.

Consequently the WQMP was developed consistent with the direction from ANZECC/ARMCANZ (2000).

When the Guidelines for Recreational Use of Water ANZECC/ARMCANZ (2000) is revised, it will take into account the assessment of risk to public health in the use of recreational water, an assessment of the indicators of pollution, the level of exposure associated with the recreational activity and a number of other factors.

It is expected that the risk-based approach will provide a more effective set of management guidelines.

4.3 Existing Management Practices

The Lake is managed by several programs that are structured according to a series of functions and operations requiring different skills and experience. Depending on those requirements, functions are managed by different programs contracted to external agencies.

A brief summary of Lake Programs are outlined below. The various aspects of water quality criteria relating to those functions are also outlined.

The functions identified above contribute to the maintenance of an acceptable quality of water in the Lake. The operation and maintenance of the Lake and Dam can significantly influence the quality of water in the Lake. The regular cleaning of decaying or green debris and pollutants in the water body and along the foreshores minimises undesirable water quality conditions.

The Authority manages comprehensive water quality programs to test and report on a range of physical, biological and chemical properties. The quality of the water is measured against the parameters for the protection of aquatic ecosystems and recreational water quality as set out by ANZECC/ARMCANZ (2000).

4.4 Recent Incidences of Elevated Bacterial Levels

A concern in the past has been elevated bacterial levels at certain times of the year. These events tend to happen in late summer and early autumn periods with bacterial levels reaching a bloom condition for a short time (typically ten to fifteen days) before counts return to normal levels. The occurrence of such events has been sporadic in the past. However, the frequency of such events has probably increased, with at least one to two events recorded in each of the last two years (Lawrence, 2001).

These conditions necessitated the closure of recreational beaches and, in some cases, closure of the whole Lake, even though no evidence was found to suggest that the elevated counts were caused by any sources of faecal pollution. Warnings about the risks of using the Lake were also issued.

Unexpected changes in water quality can severely disrupt lake-based recreational and commercial activities and cause inconvenience to prospective attendees. Effective management of bacterial problems is imperative to support aquatic sports all year around, including nationally significant events that are important to the National Capital.

4.4.1 Responses During Elevated Bacterial Counts

During periods of elevated bacterial counts, the initial responses have primarily focused on protecting the public from health risks associated with possible faecal contamination. Sanitary surveys, additional confirmation testing, and assessment of alternate indicators have also been carried out. No evidence has been found to suggest that the elevated counts were caused by any sources of faecal pollution.

However, due to the elevated counts of bacteria, the appropriate management measure has been Lake closure, despite inconvenience to the users of the Lake and particular inconvenience to commercial operations. In recognising the concerns, the Authority also:

• Invited the Cooperative Research Centre for Freshwater Ecology of the University of Canberra to undertake a study of the bacterial problems to ascertain whether or not they represented actual faecal pollution in the Lake (Lawrence, 2001). The study included a review of the appropriateness of the management responses.
• Commenced research works to identify causes of or environmental conditions responsible for the growth of bacteria including whether or not these bacteria were likely to pose a risk to human health.
• Developed management strategies to address water quality problems to protect public health and minimise adverse impacts on users resulting from Lake closures.