• water management
  
  • Water overview
  • Legislation and policies
  • Water data online
  • Water access and trade
  • Water sharing plans
  • Water for the environment
  • Water quality
  • Water Compliance
  • Across the State
• vegetation
  
  
  • Vegetation overview
  • Native vegetation in NSW
  • Plantations
  • Private Native Forestry
  • Vegetation Compliance
• soils
  
  
  • Soils overview
  • Soils in NSW
  • Soils data online
  • Soil survey
  • Maps for land managers
  • Soil Conservation Schemes
  • Acid sulfate soil
  • Salinity
• wetlands, coast and floodplains
  
  • Coast and floodplains overview
  • The coast
  • Estuaries
  • Floodplains
  • Wetlands

• Facts about Wetlands »»
• Wetland Management in NSW »»
• What is Wetland Management?
• Why Manage a Wetland?
• The NSW Wetlands Policy
• Protection for Wetlands in NSW
• Some Specific Wetland Management Issue and Management Responses
• How do the New South Wales Water Reforms relate to Wetlands and their Management in NSW?
• Tips on How you can be involved in Wetland Management in NSW?
• The Wetland Recovery Plan
• Managing Wetlands on Your Property
• Wetlands and Activities in Your Area »»

• Site search:

Home > Water Management > Water for the environment > Wetlands > Wetlands

Wetlands

Some Specific Wetland Issues and Management Responses

• Introduction
• Some Specific Wetland Issues
  • Grazing
  • River Regulation
  • Wetland Water Regimes
  • Acid Sulfate Soils
  • Wetlands and Salinity
  • Water Quality
  • Mosquitoes
• Some Specific Wetland Management Responses
  • The Wise Use Concept
  • Wetland Rehabilitation
  • Wetland Monitoring
  • Constructed Wetlands
• Some other References & Further Reading

Introduction

In order to manage wetlands effectively, it is necessary to have adequate knowledge of the major issues that do or have the potential to impact on wetlands, the flora and fauna communities within them, and the people living around them. Some issues and management responses relating to wetlands are described below.

Some Specific Wetland Issues

Grazing

Grazing in wetlands is extremely widespread in NSW. Wetlands can provide valuable grazing land for domestic animals. They have also been utilised as drought refuges when other areas have dried out. Unfortunately the impact of domestic livestock on the ecological processes in wetlands is poorly understood. The challenge is to use the grazing benefit without permanently degrading its ecological values. Overgrazing by livestock can degrade the value of the wetland through trampling vegetation, compacting soil, disturbing sediments in water and increasing nutrient levels.

The grazing of wetlands needs to be of low enough intensity to ensure that the impacts on wetland flora are minimised and that organic matter is retained. If grazing is determined to be an appropriate part of the management of a wetland, then a grazing regime can be developed. A suitable grazing regime may include a stocking rate less than carrying capacity to minimise impacts on grazing sensitive indigenous species.

Further Reading

Brock, Margaret. A (2000). How do water regime and grazing alter the reproductive capacity of aquatic plants? LWRRDC, UNE, DLWC & EA.

Department of Conservation and Natural Resources (1993). Draft Technical Paper. Livestock Grazing in Wetlands. Implications for Management. Department of Conservation and Natural Resources, Wetlands Unit, Melbourne.

River Regulation

River regulation structures such as major water storages, inland diversion schemes, locks and weirs have modified the hydrology and water regimes of wetlands. The effects of river regulation vary according to a number of factors including the distance downstream, local hydraulic moderations and the structures present.

Impacts on wetlands as a result river regulation are compounded by land uses such as flood control and runoff works, land clearing, river management works (desnagging, dredging), drainage works and modification to groundwater (DWR, 1991; NSW Water Resources Council, 1993)

River regulation impedes essential biophysical functions and modifies flow patterns and flooding characteristics. Generally, the range and size of regulated flows in comparison with channel capacity is higher upstream. The frequency and duration of flows in the regulated range have been increased in most wetlands (DWR, 1991). Where the frequency and duration of regulated flows have been increased, permanent swamps have been created. Where flows have been excluded, wetlands are also significantly modified. So, for example, a shallow open water or rush wetland may eventually turn into forest habitat (DWR, 1991). There are three main factors that usually cause decreased flow into wetlands. They are a reduction in catchment area, diversion of flows and harvesting of unregulated flows (Keyte, 1994).

As a result of changed flow patterns, flood peaks are reduced, river levels stabilised, and the ecology of some sections of channels changed from flowing to still (NSW Water Resources Council, 1993). The frequency of low-level inundation is increased as a result of releases for downstream uses. This in turn reduces small and medium sized floods and leads to erosion of rivers and channels (Pressey et al., 1984, Brereton, 1994). Seasonal flows may be modified through irrigation extractions in summer and tributary flooding in winter. Flows are affected immediately downstream of major storages as well as further downstream, although to a lesser degree (DWR, 1991).

The majority of major rivers in NSW are regulated. Rivers with storage capacities significantly larger than yearly discharge are the Murrumbidgee, Upper Murray and Gwydir Rivers. The Murrumbidgee River has a regulated flow not much less than its total annual discharge, thus indicating a high degree of regulation (King, unpubl.).

The Murray River is the most regulated river in New South Wales. Approximately 42% of the total wetland area along the Murray River is above the level of regulated flow. This restricts the supply of water in periods of surplus. The frequency of high flows along the Murray have been reduced by 50%. The construction of weirs along the Murray has lead to the permanent inundation of approximately 35% of the wetlands. Of the water available for use, approximately 91% is committed for human use (Pressey, 1986; Walker, 1992).

Weirs

Pool areas in weirs and locks can lead to the permanent inundation of wetlands upstream of major water storages. Weirs result in raised water levels, ponding of flows and the establishment of permanent connections to adjacent lentic wetlands. Flow regimes of coastal and inland rivers and streams are affected downstream of impoundments. Weirs and in-channel structures can alter flow characteristics such as velocity, water quality, depth and wetted area which influence habitat values (NSW Water Resources Council, 1993).

Storages

Wetlands are sometimes used as storage sites for drainage water before it is released onto other sites or to a river channel. Stored drainage water degrades wetlands through reduced water quality, reduced diversity of macrophytes and benthic fauna and inhibition of seed germination and seedling growth.

Essentially, natural wetlands should not be used as off-river storages as this results in changes to the inundation patterns of wetlands. Sudden and rapid changes in water levels in wetlands have a number of serious impacts, e.g. waterbird breeding cycles can be interrupted or cut short. Wetlands currently used as off-river storages should ideally have an inundation pattern as close to the natural flow patterns as possible (DWR, 1994).

Irrigation

Natural inflows into wetlands may be affected by irrigation supply systems. As a result of diverting water for irrigation purposes there may be a net loss of flow volume downstream of the irrigation areas, thereby affecting natural inflows into wetlands (DWR, 1991).

Water Use

The use of water from wetlands for domestic, industrial and agricultural purposes can lead to water level drawdown and premature drying. Urban, industrial or agricultural wastewater entering wetlands may contain pesticides, heavy metals, oils and nutrients. Although many wetlands act as efficient filters, sudden increases in large amounts of nutrients and wastes can degrade water quality and the flora and fauna the wetlands support.

Floodgates

The establishment of floodgates can prevent the refilling of wetlands. This is most evident in tidal wetlands where outflow of floodwaters is not restricted but tidal exchange is. Impacts of floodgate controls include a decline in mangroves, interruption to fish passage, the loss of organic detritus, loss of seagrass beds and a decrease in the diversity and abundance of estuarine fauna (Pressey and Harris, 1988).

References & Further Reading

Brereton, G.J. (1994). "An Investigation into the Impact of Erosion in the Southern Macquarie Marshes. Natural Resources Management Strategy Project". Macquarie Marshes Management Strategy Stage 1. Biophysical Investigations. Department of Water Resources, Macquarie-Western Region.

Department of Water Resources (1991). Draft Report of the New South Wales Murray Wetlands Working Group. Department of Water Resources Technical Services Division, Parramatta.

Department of Water Resources (1994). Wetland Management: Interim Instructions for DWR Staff. DWR, Parramatta, NSW.

Keyte, P.A. (1994). Lower Gwydir Wetland Plan of Management - 1994 to 1997. Report by NSW Department of Water Resources for the Lower Gwydir Wetland Steering Committee, Sydney.

King, A.M. (Unpublished). Status Overview of NSW Wetlands. Department of Water Resources Environmental Studies Unit, Parramatta, NSW.

Kingsford. R. (2000). Ecological impacts of dams, water diversions and river management on floodplain wetlands in Australia. Australian Journal of Ecology (2000) 25, 109-127

New South Wales Water Resources Council (1993). The New South Wales State Rivers and Estuaries Policy. NSW Government.

Pressey, R.L. and Middleton, M.J. (1982). Impacts of flood mitigation works on coastal wetlands in New South Wales. Wetlands (Australia), 2: 27-44.

Pressey, R.L., Bell, F.C., Barker, J., Rundle, A.S. and Belcher, C.A. (1984). Biophysical Features of the Lachlan-Murrumbidgee Confluence, Southwestern New South Wales. NSW National Parks and Wildlife Service.

Pressey, R.L. (1986). Wetlands of the River Murray Below Lake Hume. River Murray Commission Environmental Report 86/1.

Pressey, R.L. and Harris, J.H. (1988). "Wetlands of New South Wales". In The Conservation of Australian Wetlands. (Eds A.J. McComb and P.S. Lake). pp.35-57. Surrey Beatty and Sons Pty. Ltd.; WWF Australia.

Walker, K.F. (1985). A review of the ecological effects of river regulation in Australia. Hydrobiologia, 125: 111-129.

Walker, K.F., Hillman, T.J. and Williams, W.D. (1978). The effects of impoundment on rivers: an Australian case study. Verh. Int. Verein. Limnol., 20: 1695-1701.

Walker, K.F. (1992). A Review of the Ecological Effects of River Regulation in Australia. Department of Zoology, University of Adelaide, Adelaide.

Wetland Water Regimes

Policy Context - Principle 1 of the NSW Wetlands Management Policy 1996.

Natural hydrologic processes promote optimal wetland functioning, thereby preserving significant wetland values. As such, the management of wetlands often evolves around hydrologic or ecological processes that are linked to hydrology.

Seasonality, frequency, duration and depth of inundation comprise the water regime of a wetland. These factors may vary significantly from wetland to wetland depending on factors such as wetland type and location. The characteristics of a water regime may also vary along the length of the same river.

The plants and animals that live in many wetlands are adapted to wet and dry cycles. Many of the chemical processes which support life in these wetlands are also triggered by alternating wet and dry periods. If these patterns are disturbed, the wetland may be degraded (DLWC, 1996).

The productivity of wetlands can be adversely affected as a result of altered water regimes. Prolonged inundation decreases the rate at which organic material is broken down and may result in changes to the composition of plant species. For example, re-establishing and/or maintaining the flooding and drying cycle is an integral part of reed swamp management. Several species of flora and fauna have adapted over thousands of years to the cycle of flooding and drying. Changes to this process may result in the loss of species and alter the composition of plants and animals.

The management of wetlands needs to consider the state of wetlands when dry as well as when flooded. This involves identifying the differences between wet and dry periods, for example, the formation of salt crusts, species composition, etc. It is important to remember that some wetlands, particularly in arid areas may only function for a short period of time.

References & Further Reading

Brock, Margaret. A (2000) How do water regime and grazing alter the reproductive capacity of aquatic plants?. LWRRDC, UNE, DLWC & EA.

Brock, M. A. (1998). "Are aquatic plant seed banks resilient to water regime alteration? Implications for the Paroo River System. Pp 1129 - 138 In Kingsford, R.T. (Ed) Free Flowing River: the ecology of the Paroo River. National Parks and Wildlife Service, Sydney.

Brock, M. A., Smith, R.G.B. and Jarman, P.J. (1999). Drain it, dam it: alteration of water regime in shallow wetlands on the New England Tableland of NSW. Wetlands Ecology and Management 7: 37-46.

Casanova, M.T. and Brock, M.A. (2000). How do depth, duration and frequency of flooding influence the establishment of wetland plant communities? Plant Ecology 147: 237 - 250.

Crossle, K. and Brock, M.A. (in prep). Water regime, propagule type and plant species richness: the importance of dry times for wetlands.

Department of Land and Water Conservation (1996). The NSW Wetlands Management Policy. NSW Government, Sydney.

Roberts, J. and Marston, F. (2000). Water regime of wetland and floodplain plants in the Murray-Darling Basin. CSIRO Land and Water, Canberra. Technical Report, 30/00.

Warwick, N.W.M. and Brock, M.A. (in prep). The effect of timing, depth and duration of flooding on the growth and reproduction in wetland plants.

Acid Sulfate Soils

Acid sulfate soils occur naturally on the low lying coastal floodplains of the NSW coast. However, they contain iron sulfides (mainly pyrite), which when disturbed and exposed to air can release sulfuric acid into groundwater and surface water. Acidic water can cause fish kills, reduce farm productivity, release heavy metals from contaminated sediments, pollute water, impact on human and animal health, damage infrastructure such as bridges, and can dramatically alter the ecological character of wetlands and estuaries.

In July, 2000, The National Working Party on Acid Sulfate Soils released the Australia National Strategy for the Management of Coastal Acid Sulfate Soils. The Strategy provides a framework for governments, industry and the community to manage development on these soils.

For more information on Australia National Strategy for the Management of Coastal Acid Sulfate Soils or on acid sulfate soils in general please refer to NSW Agriculture's Acid Sulfate Soils Information Page.

Environmental Protection Authority (1995). Environmental Guidelines for Assessing and Managing Acid Sulfate Soils, Environment Protection Authority, Sydney.

Wetlands and Salinity

Salinity is a threat to the health and productivity of many catchments, and to the rural and urban communities that live in them. The NSW Government has recently released its Salinity Strategy outlining the way forward for salinity management in NSW. As a part of this process the Department has produced a report on the "Potential Environmental Consequences of Increasing Dryland Salinity on Streams and Wetlands Within the Murray - Darling Basin in New South Wales". This report is part of a larger report which deals with "Salinity Predictions for NSW Rivers in the Murray - Darling Basin" (DLWC 1999).

Salinity and the Great Cumbung Swamp

Salinity and the Gwydir Wetlands

Salinity and the Macquarie Marshes

References & Further Reading

Department of Land and Water Conservation (1999). Potential Environmental Consequences of Increasing Dryland Salinity on Streams and Wetlands within the Murray - Darling Basin in New South Wales. From: Salinity Predictions for NSW Rivers in the Murray - Darling Basin.

Water Quality

Policy Context - Principle 4 of the NSW Wetlands Management Policy 1996.

Water quality is an important consideration in wetland management. Wetlands have the ability to "treat" polluted water by absorbing excess nutrients and sediments. However, wetlands filled with unacceptably high levels of pollutants will become severely degraded. Management practices should therefore consider the effect of water quality on the total value of the wetland. For example, salinity, turbidity, nutrients, dissolved oxygen, pesticides, acidity and chemicals will impact on the flora and fauna in the wetland.

Mosquitoes

Wetlands are aquatic habitats for a variety of vertebrate and invertebrate fauna. Amongst the vertebrate fauna, mosquitoes are of particular importance because they present a pest disease potential for nearby human communities. Wetlands can be managed to minimise mosquito problems.

There are hundreds of species of mosquitoes in Australia. In south eastern Australia there are approximately 120 known species, although probably less than 20 of these are of any concern as pests or carriers (vectors) of disease to humans.

Mosquito biology and ecology can vary with species, and different species can occupy different environmental niches within a single wetland. Mosquitoes require a body of water for the development of their immature stages (larvae and pupae), although the nature of the habitat and the duration of the association vary and are often characteristic of the species.

The nature of a wetland, its form and vegetation, will determine to a great extent the nature of the mosquito fauna. Most mosquito-borne pest and disease problems depend on mosquito abundance, contact with humans and environmental factors such as temperature and humidity. The hazard and risk from mosquitoes and pathogens can therefore be gauged to some extent by surveillance.

More information on mosquitoes and wetland management can be found in the Department's Constructed Wetlands Manual available through the Department's information Centre on telephone: 02 9228 6333 or at info@pnr.nsw.gov.au or on the NSW Health website.

References & Further Reading

Department of Land and Water Conservation. (1998). The Constructed Wetlands Manual. Volume 1. DLWC, NSW.

Some Specific Wetland Management Responses

The Wise Use Concept

The wise use concept was defined at the 3rd Meeting of the Conference of the Ramsar Contracting Parties held in Regina, Canada, in 1987 (Recommendation 3.3), as "the sustainable utilization of wetlands for benefit of humankind in a way compatible with the maintenance of the natural properties of the ecosystem".

Wise use activities can be varied in nature, ranging from very little or no resource exploitation, to active resource exploitation as long as it is sustainable. It must be recognised, however, that very few wetlands are not currently being utilised by local populations in some way. Wetland management should be adapted to specific local circumstances, sensitive to local cultures and respectful of traditional uses. Management therefore is not a universal concept that can be broadly applied; rather, it needs to be adapted to suit local conditions (Ramsar Bureau Website, 2000).

Wetland Rehabilitation

Policy Context - Principles 2 and 7 of the NSW Wetlands Management Policy 1996.

Wetland Rehabilitation (sometimes referred to as 'Restoration') is defined by Whitaker (1998) as:

• Activities carried out in or around natural wetland areas that improve the function and ecological status of: an identified species; a recognised habitat; and/or the general wetland environment.
  
  
• Activities that reduce the gap between the advantages that wetlands provide today and the advantages that they could or should be providing.
  
  
• A part of wetland management just as a person's recovery (rehabilitation) from illness or injury, is a part of their healthy lifestyle management. Rehabilitation is not a replacement for conservation.

Rehabilitating wetlands involves identifying the natural processes of the wetland and minimising or decreasing threatening activities. Any works undertaken to improve the status of a wetland should be simple and introduced slowly so that a minimum amount of disturbance occurs.

The process of rehabilitation involves, but is not limited to:

• assessing existing condition;
  
  
• identifying the sources of water;
  
  
• identifying the water regime of the wetland in terms of seasonality, frequency and duration of inundation, etc.; and
  
  
• consideration of the activities which need to be undertaken to rehabilitate the wetland. For example: excluding grazing; slashing or mowing firebreaks around the perimeter of grassland or woodland wetlands which are not grazed; establishing and maintaining an open area for native ground cover plants and for native wildlife to graze; control pest animals and plants; fencing, earthmoving, blocking drains to divert chemical laden water away from the wetland; determining flora and fauna requirements; considering the "do nothing" option of management in areas where the natural processes will re-establish the wetland (Richardson, 1998).

A number of successful wetland rehabilitation projects have been carried out across NSW. Others are currently underway. Further details on these projects can be found in the "Wetlands and Activities in your Department Region" pages of this site.

For SEPP 14 - Coastal Wetlands Department of Urban Affairs and Planning (DUAP) has developed guidelines for the development of Wetland Restoration Plans. The guidelines explain how to go about preparing a plan to restore a wetland area that has been damaged or destroyed through land clearing, drainage and/or filling. Further details are available on DUAPs website.

References & Further Reading

Collins, C. (2000). A guide to wetland rehabilitation for community groups in NSW. WetlandCare Australia, Ocean Watch and NSW State Wetland Action Group.

Department of Land and Water Conservation (1996). The NSW Wetlands Management Policy. NSW Government, Sydney.

Leadbitter, D. (Ed). (1995). Reversing the Trend - restoration, rehabilitation and re-creation of wetlands. Wetlands (Australia). Journal of the Coast and Wetlands Society Inc, Sydney.

Richardson, R. (1998). Unpublished Report. Wetland Management Technical Manual: Water Management. DLWC, Sydney.

Streever, W. J. (1997). Trends in wetland rehabilitation. In Wetlands Ecology and Management 5: 5-18. Kluwer Academic Publishers.

Whitaker, M. (1998). Issues and Recommendations Relating to Wetland Rehabilitation in NSW: Discussion Paper prepared for the State Wetland Action Group under the National Wetlands Program.

Wetland Monitoring

Policy Context - An identified outcome of Principle 9 of the NSW Wetlands Management Policy 1996.

Monitoring is the process of measuring change in ecological character in any wetland over a period of time (Ramsar Bureau Website, 2000).

Monitoring is an ongoing part of wetland management. The condition of wetlands can be assessed by checking environmental conditions and matching these with management aims and objectives. In a wetland environment, many different attributes can be monitored depending on the purpose of the monitoring project.

Attributes include (taken from Green, 1998):

• Hydrology - impact of structures, frequency of inflows, duration of inundation, depth of inundation, outflows, duration of dry periods;
  

• Fauna - macroinvertebrates, waterbirds, frogs, fish, species diversity, species abundance, species distribution, important species, breeding events;
  
  
• Vegetation - species diversity, species abundance, species distribution, growth, health and important species;
  
  
• Water quality - pH, turbidity, algal counts, temperature, dissolved oxygen;
  
  
• Landuse - within a wetland or within the catchment;
  
  
• Geomorphology;
  
  
• Aquatic habitat - diversity of habitats, bank stability, landuse changes;
  
  
• Soils and substrate - texture, organic matter, nutrient status; and
  
  
• Groundwater.

The results obtained through monitoring can help managers to prioritise management actions and keep track of the health of the wetland.

DLWC is involved in the monitoring of wetlands throughout NSW. Specific details can be found on the "Wetlands & Activities in your DLWC Region" pages of this site.

Green, D. (1998). Wetland Monitoring Workshop. In Proceedings of the Department of Land and Water Conservations Wetlands Conference and Workshop, 28-30 April, 1997, Myall Shores, Myall Lakes National Park.

Constructed Wetlands

Policy Context - Principle 5 of the NSW Wetlands Management Policy 1996.

Wetlands are increasingly being created in urban and rural residential developments to improve wildlife habitats and the quality of storm and waste water, as well as producing a pleasing environment for local residents. When wetlands are designed and constructed correctly they can reduce the levels of nutrients, litter, sediments, pathogens, heavy metals and hydrocarbons in water. While the NSW Wetlands Management Policy covers only natural wetlands, the Government recognises the existence and use of constructed wetlands in other ways. In September 1998, the Minister for Land and Water Conservation launched the Constructed Wetlands Manual, a blueprint for constructed wetlands and the first of its kind in Australia. The result of three years research and development by the Department, the manual draws together the expertise of the constructed wetlands industry. The manual aims to reduce some of the high costs associated with this type of project and produce a better functioning wetland. (DLWC, 1999).

While constructed wetlands fulfil an important role in improving water quality, they cannot replace all the values of natural wetlands. For this reason, they should be seen as a way of enhancing existing wetland systems, not replacing them (DLWC, 1996).

The Manual should be read in conjunction with the NSW Wetlands Management Policy and Action Plan, and the Wetland Policy of the Commonwealth Government of Australia. Copies of the Constructed Wetlands Manual can be purchased through the Department's Information Centre on 9228 6415 or info@dnr.nsw.gov.au.

References & Further Reading

Department of Land and Water Conservation (1996). The NSW Wetlands Management Policy. NSW Government, Sydney.

Department of Land and Water Conservation. (1998). The Constructed Wetlands Manual. Volume 1. DLWC, NSW.

Some other References & Further Reading

Briggs, S.V. (1988). Guidelines for management of inland wetlands in southern New South Wales. Wetlands (Australia), 8(1): 1-2.

Bacon, P., Ward, K., Craven, P., Harper, M. and Bone, B. (1994). "Floodplain land-use issues in the Murray-Darling Basin". In Murray-Darling Basin Floodplain Wetlands Management. Proceedings of the Floodplain Wetlands Management Workshop. 20-22 October, 1992. (Eds T. Sharley and C. Huggan) pp. 42-52. Murray-Darling Basin Commission, Canberra.

Department of Land and Water Conservation (1996). The NSW Wetlands Management Policy. NSW Government, Sydney.

Lugg, A. (1993). Wetland Management: Guidelines for Local Councils in the Murray Region of NSW. Murray Wetlands Working Group, NSW.

McComb, A.J. and Lake, P.S. (1990). Australian Wetlands. Collins/Angus and Robertson Publishers, NSW.

Pressey, R.L. and Harris, J.H. (1988). "Wetlands of New South Wales". In The Conservation of Australian Wetlands. (Eds A.J. McComb and P.S. Lake). pp.35-57. Surrey Beatty and Sons Pty. Ltd.; WWF Australia.