Lower Lakes, Coorong and Murray Mouth

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Ramsar habitat mapping

Given the international importance of the Lower Lakes wetland system, a habitat condition study was commissioned in February 2010 to document the impact of the drought. A stratified repeated measures study design was used to compare the 2010 condition of the Lower Lakes wetlands to a baseline condition assessment of the same wetlands that was undertaken in 2003 (Seaman 2003).

The objective of this study was to assess the impact of drought on wetland condition within the Lower Lakes area. The project also assessed the relative benefit of intervention management strategies by comparing managed versus non-managed wetlands.

The study found that intervention management techniques that were applied preserved wetlands but those sites that were not managed suffered a decline in condition and in some cases a change in vegetation community. A clear example of a management intervention that contributed to habitat condition being maintained is Turvey’s Drain, located near Milang at Lake Alexandrina. Turvey’s Drain has a reed bed (Typha sp.) vegetation association which was managed as a fish refuge during the drought and due to the artificial watering that this drain received throughout the drought the condition of the wetland habitat was preserved, whereas a similar wetland habitat in Tolderol Reserve that had the same Ramsar classification received no artificial watering and consequently the wetland dried out and the vegetation community changed from a reed bed (Typha sp.) to a terrestrial habitat dominated by introduced grasses and samphire. This example illustrates changes that occur in condition and communities when water levels are reduced in the Lower Lakes.

Similarly, Narrung Wetland received artificial watering via pumping from Lake Alexandrina whilst under the management of the Narrung Wetland Management Plan (Bjornsson 2006). The Coorong–Tatiara Local Action Plan and the SA Murray–Darling Basin Natural Resources Management Board managing Narrung Wetland were concerned about the potential loss of the seed bank through rainfall germination and prolonged drought conditions. Seed banks play an essential role in the persistence of wetland plant species during adverse conditions such as drought, therefore ensuring the seed bank remained viable was an immediate management action necessary to maintain a resilient wetland. Hence, given that the duration of the drought period was unknown, the Coorong–Tatiara Local Action Plan and the SA Murray–Darling Basin Natural Resources Management board chose to proactively manage Narrung Wetland to ensure the seed bank was not lost. The strategy they applied included fencing the wetland, obtaining an environmental water allocation to deliver environmental water to the main wetland basin via pumping water from Lake Alexandrina and implementing a revegetation program. When assessing the site, revegetation and environmental water added diversity and structure and a viable seed bank, thus the site was assessed to be in good condition compared to its 2003 degraded condition. Hence, this case study exemplifies the benefits of management interventions in protecting wetland systems.

Acid sulfate soil and water quality monitoring

Soil monitoring

Acid sulfate soil monitoring was carried out by CSIRO on behalf of the SA Murray–Darling Basin Natural Resources Management Board in 2009–10 to investigate representative environments in Lakes Alexandrina and Albert and assess the implications of lowering and rising water levels in the Lower Lakes in relation to the development of acid sulfate soils.

Following on from this 2009/10 monitoring, CSIRO has continued acid sulfate soil monitoring of the Lower Lakes as part of DENR’s Murray Futures Program. This will be effective for understanding how soils change over time and the hazard they pose to ecosystems and human health. The surveys can assist in highlighting high-risk or hotspot areas, and will inform the need for, and effectiveness of, management actions (e.g. limestoning) necessary to mitigate acidification risks.

Monitoring locations include Currency Creek, Finniss River, Narrung, Waltowa, Loveday Bay, Dunns Lagoon, Boggy Creek system and Tolderol.

Community acid sulfate soil monitoring

In 2009–10 a community acid sulfate soils monitoring program occurred due to community concern about the ecological, economic and recreational impacts of the degradation of the Lower Lakes. The program coordinated by the Lakes’ Remediation Project Officer is the recruitment of community volunteers to monitor acid sulfate soil changes along the lakes’ shoreline. The volunteers are using an Acid Sulfate Soil Field Guide specifically adapted by CSIRO Land and Water for easy use. The field guide outlines a systematic protocol for sampling site selection, sampling methodology, soil description and field testing (pH and electrical conductivity (EC)).

Water quality monitoring

The Lower Lakes region monitoring program includes continuation of ambient water quality monitoring within the Lower Lakes region and event-based monitoring covering:

a. response monitoring associated with known hotspot areas including:

• the Goolwa Channel Water Level Management Project

• the Lake Albert Water Level Management Project

• lake margins around in Lake Alexandrina such as Boggy Lake, Loveday Bay, Salt Lagoon, Dunns Lagoon and creeks on Hindmarsh Island

b. groundwater (sediment porewater) monitoring using piezometers within Lakes Albert and Alexandrina and the tributaries to help assess the risks of acidic groundwater reaching the lakes

c. benthic ecological monitoring in relation to acid sulfate soils to assess impacts and recovery.

The overall objectives are to use the monitoring data to make informed management decisions by:

• providing early warning of changes to water quality and ecology in the Lower Lakes that indicate imminent acidification

• validating hydrodynamic and alkalinity trigger prediction models and more accurately predict changes that occur as the result of low flows, low lake levels and acid sulfate soil re-wetting (via rainfall or inflows)

• assessing the impacts of low inflows, changes in lake levels and acid sulfate soils on the ecological communities in the region

• examining the effectiveness, or any adverse impacts, of implemented management actions over time.

Bioremediation study

This study is led by Southern Cross University as part of the Murray Futures Program. The aim is to measure the impact of carbon additions through the lake stabilisation program in facilitating sulfate reduction.

Goolwa Channel Water Level Management Project

An extended period of low inflows from the River Murray negatively impacted the ecological condition of the Coorong and Lower Lakes (CLLMM) region. As part of the CLLMM region, the Goolwa Channel and its associated tributaries (Finniss River and Currency Creek) experienced significant declines in water levels, exposing vast areas of sulfidic sediments. When exposed to air, sulfidic sediments can produce acid sulfate soils which can release acidity in the form of sulfuric acid as well as toxic quantities of iron, aluminium and other metals into the water column.

In order to mitigate the risk of acidification, the Australian Government through a Ministerial Council decision constructed a temporary earthen regulator in the Goolwa Channel as a part of the Goolwa Channel Water Level Management Project. This regulator allowed the inundation of acid sulphate sediments in Currency Creek, Finniss River and the Goolwa Channel west of Clayton. Inundation of the sediments with freshwater prevents exposure and prevents acidification of the aquatic environments.

Year 1 of the Goolwa Channel Water Level Management Project monitored the response of water quality, phytoplankton, zooplankton, macroinvertebrates, vegetation, fish and birds to the construction of the Clayton regulator in August and September 2009, the subsequent rise in water levels and the changing environmental conditions within the Goolwa Channel. A final synthesis report on this first year of monitoring is now available.

A Goolwa Channel Water Level Management Project ecological monitoring review workshop was held in July 2010 and its recommendations were used to design the ecological monitoring activities for year 2. As the Clayton regulator was breached in September 2010 as a result of greater than expected inflows, the objectives of year 2 ecological monitoring are different to that of year 1, instead monitoring the response of biota to the breach and subsequent reconnection to Lake Alexandria and the change in environmental conditions within the Goolwa Channel. Southern bell frogs were added to the biota being monitored.

Barrage release monitoring

As a result of greater than expected rainfall and inflows into the CLLMM region in winter and spring 2010, the first barrage flows since 2006/2007 began on 4 September 2010. A joint monitoring process between DENR and Department for water has led to the biotic response to these flows being monitored in the Murray Mouth and Coorong regions from November 2010. Biota, parameters and processes being monitored include water quality, nutrients, phytoplankton, zooplankton, fish, birds, macroinvertebrates, recruitment and connectivity.

Department of Environment and Natural Resources Long-term Plan adaptive management and monitoring

Adaptive management

Coorong, Lower Lakes and Murray Mouth Projects are developing a structured adaptive management process through which the proposed goals, objectives and management actions of the CLLMM Long-term Plan can be implemented through all future scenarios.

Adaptive management uses both existing and developing knowledge and understanding to assist with identifying what can be done to address issues or threats affecting the site, how proposed management action(s) might achieve this, and why. This is then documented and forms a management plan or roadmap. By utilising the learnings from an effective and well-planned monitoring framework, input from community and scientific reference groups and targeted research to fill key knowledge gaps, future decisions for the site will be improved as the information upon which decisions are based is improved, resulting in the best possible outcomes for the site.

Adaptive monitoring

A whole-of-site Ecological Monitoring Framework and Plan will be expanded on and developed in order to: quantitatively assess changes in ecological character; assess the impact of management actions on biota and processes; and assess whether management actions are achieving their targets and objectives. The vision of this work is to develop a whole-of-site ecological monitoring framework and plan for the Coorong, Lower Lakes and Murray Mouth region for 2010–15 that integrates existing agency and community monitoring, in particular The Living Murray Condition Monitoring program, to document any ecological changes to inform the management of the site.

The framework aims to develop an adaptive ecological monitoring process through reviewing existing monitoring programmes in the region. This review has identified priority ecological monitoring requirements for 2010–11 that have the capacity to undergo review and adaptation for extension beyond 2011.

Gap analysis on current ecological monitoring activities in parallel with discussions with stakeholders identified several common themes including: increasing contractor stability through funding availability and commitment; the necessity of objective-driven ecological monitoring programmes; the importance of monitoring processes as well as biota. The importance of developing a synthesis of monitoring components for an overall understanding of biotic and process response to management actions and changing environmental conditions.

Key biota and process monitoring gaps not included in The Living Murray program but required for whole-of-site management identified include: mammals; reptiles; zooplankton; recruitment; and connectivity; as well as specific gaps for biota presently monitored (such as samphire communities as part of vegetation monitoring in the region).

In order to ensure that such monitoring gaps are filled and that monitoring informs management decisions and actions, four monitoring themes have been identified:

1. Condition/baseline monitoring will determine the current ecological condition of the biota of the CLLMM region and provide baseline data for biota and processes to inform on the ecological character of the site and limits of acceptable change that will feed into the adaptive management framework for the site. Most condition/baseline monitoring for 2010–11 will align with current TLM icon site condition monitoring.

2. Investigative monitoring will identify reasons for localised changes in ecological condition or departures from the established baseline and also identify potential methods for re-establishing the desired ecological condition. Investigative monitoring is a short-term and localised action.

3. Emergency response monitoring will be initiated in response to trigger levels identified through condition/baseline monitoring in order to assess the environmental response to the emergency (such as an acidification event) and any mitigation actions. Like investigative monitoring, emergency response monitoring is a short-term and localised action.

4. Intervention monitoring identifies that any intervention action should have its own specific monitoring programme designed to assess whether the intervention action is achieving its stated ecological objectives.

In following the Wilkinson framework, the monitoring framework and plan highlight the necessity of an overall monitoring synthesis component, as well as regular reporting requirements for each monitoring aspect, in order to create an integrated, holistic whole-of-system understanding of the monitoring programme. The regular reporting, as well as the overall synthesis, will feedback into both the adaptive monitoring and the adaptive management processes.

The adaptive monitoring framework identified in the plan ensures that the outcomes and deliverables produced by monitoring programmes are used to inform both further monitoring in the region and the adaptive management process. Priority monitoring activities identified under each of the four monitoring themes in the framework and plan will be commissioned for a maximum of one year, with an ongoing review component compulsory during the year. This will allow the adaptation of the monitoring programme for further years, if required, in order to inform all management decisions and actions and to assess that the programmes’ objectives are being met.

Information provided through regular reporting and the monitoring synthesis is fed into the adaptive management process through the governance structure of the CLLMM Project identified in the framework. Therefore the adaptive monitoring framework feeds into every stage of the adaptive management framework and underpins the critical processes of planning management actions and developing the research priorities for the region for the period of 2010–15. The proposed monitoring initiatives described will require approval from the Australian Government before implementation.

1 Tom Trevorrow (2010). Murrundi Ruwe Pangari Ringbalin ‘River Country Spirit Ceremony: Aboriginal Perspectives on River Country’.

2 The long-term Cap equivalent is a type of average and takes into account different characteristics of water entitlements in New South Wales, Victoria and South Australia and their reliability. The measure of water recovery creates a common unit on measure, thus allowing equitable comparison of a broad range of water recovery measures.

3 Will be published in 2014.

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