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What is a wetland?Wetlands are areas of permanent or periodic/intermittent inundation, with water that is static or flowing fresh, brackish or salt, including areas of marine water, the depth of which at low tide does not exceed 6 metres. To be classified as a wetland, the area must have one or more of the following attributes:at least periodically, the land supports plants or animals that are adapted to and dependent on living in wet conditions for at least part of their life cycle, or the substratum is predominantly undrained soils that are saturated, flooded or ponded long enough to develop anaerobic conditions in the upper layers, or the substratum is not soil and is saturated with water, or covered by water at some time. Examples under this definition include: areas shown as a river, stream, creek, swamp, lake, marsh, waterhole, wetland, billabong, pool or spring on the wetlands Regional Ecosystems (REs) or as defined by the Environmental Protection Agency Because of the great diversity of wetlands it is necessary to divide them into broad ‘groups’ or ‘types’. For the purposes of distinguishing these different wetland types, a classification system is required. One of the broader groupings of wetlands is based on systems (marine, estuarine, riverine, lacustrine, palustrine and spring).
System DefinitionsRiverine wetlands describe all wetlands and deepwater habitats within a channel. The channels are naturally or artificially created, they periodically or continuously contain moving water, or form a connecting link between two bodies of standing water.Lacustrine wetlands are large, open, water-dominated systems (for example, lakes) larger than 8 hectares. This definition also applies to modified systems (for example, dams), which possess characteristics similar to lacustrine systems (for example, deep, standing or slow-moving waters).Palustrine wetlands are primarily vegetated non-channel environments of less than 8 hectares. They include billabongs, swamps, bogs, springs, soaks etc, and have more than 30 percent emergent vegetation.Spring wetlands occur where groundwater flows out of the ground forming pools or streams.
Marine wetlands include the area of ocean from the coastline or estuary, extending to the jurisdictional limits of Queensland waters (3 nautical mile limit). Estuarine wetlands are those with oceanic water sometimes diluted with freshwater run-off from the land.
Why are wetlands important?Each wetland system has its own uniqueecosystem of plants and animals that depend on the wetland for food, waterand shelter.Wetlands are vital to Australia. They protect our shores from wave action,reduce the impacts of floods, absorb pollutants and provide habitat for animalsand plants. Wetlands are important in other ways as well. They purify waterand are important for recreational activities. They form nurseries for fish andother freshwater and marine life and, because of this, they are critical toAustralia's commercial and recreational fishing industries. In the tropics,wetlands are vital waterways that reflect the health of the catchments.Wetlands may also be areas of great beauty where people enjoy the sceneryand gather for recreation. They also bear historical significance with somehaving high cultural value. In particular, many wetland areas throughoutAustralia are important to Aboriginal people. Consideration of these historicaland cultural relationships is a fundamental part of wetland management.Wetlands are under pressure. Since European settlement, many have beenaltered or destroyed for land uses such as urban development and agriculture.Of those that survived, many are now being degraded by land clearance,filling, stock grazing, dumping of refuse and littering. Surface water runoffcontaminated by fertilisers, pesticides, herbicides, detergents and petroleumproducts is changing the natural balance of wetlands.To protect and conserve wetlands we need to understand them and learn howto manage them wisely. A great deal of work is already being done toconserve and manage wetlands in Australia.
Why are wetlands protected?Over 50% of our wetlands have been significantly affected throughdegradation or loss since European settlement. For example, catchmentsadjacent to the Great Barrier Reef have been extensively cleared andmodified for urban development, aquaculture development and agriculturalactivities such as cattle grazing and cropping. The protection of wetlands iscritical to help ensure the survival of the Great Barrier Reef.Who protects wetlands?The preservation and rehabilitation of wetland areas is a major environmentalpriority for the Australian and Queensland Government’s Reef Water QualityProtection Plan. Communities, industries and governments are workingtogether to raise awareness of the effects of wetland clearing and to helpprotect wetland areas for the future. A number of community projects havebeen developed to help prevent the decline of these important environments.For information about how you can become involved in a wetland protectionproject in your area, contact your local Council or your local Regional NaturalResource Management Group at http://regionalnrm.qld.gov.au/about/regional
Site descriptionFrom WetlandLinkThe Bohle Wetlands Rehabilitation Project was established in 2005 through the signing of a Memorandum Of Understanding between the Department of Environment and Resource Management (DERM) and Conservation Volunteers Australia (CVA). The agreement provides a framework for cooperation between both parties to deliver on common objectives in relation to the rehabilitation of the wetland site. The project site is a Wildlife habitat corridor along the Bohle River. It is characterized as a Riparian Corridor with minor drainage lines. The wetland and river are a part of a system composed of mangrove estuaries, saltpans, brackish sedgelands and freshwater swamps running from Harvey’s Range to the ocean. The site lies approximately 12kms due west of the Townsville CBD. It can be found whilst travelling north along the Bruce Highway on the left side immediately before the Bohle River bridge. The 8.1 ha wetlands site is situated within the Bohle River Catchment which covers approximately 355 km2. See Bohle Wetlands Rehabilitation Site Map.The wetlands system within the site holds significant value as it contributes to the health of the Bohle River. This wetland system plays a vital role in removing nutrient loads and pollutants from the waterway that has the potential to flow into the ocean. This is achieved by the plant species that are present within the site absorbing and filtering out all the pollutants and then slowly allowing the cleaned water to be released back into the Bohle River system. The Natural Habitat Quality of the wetland site is listed as a Disturbed Habitat and its Conservation Value is currently undefined. However the area is a declared fish habitat area - Management 'B' under the Queensland Fisheries Act and it is also a recognized habitat for various bird and mammal species as well as estuarine crocodiles.
Catchment From WetlandLink The Bohle River catchment area is approximately 355km2 (Maunsell McIntyre, 2000). It drains most of the Coastal Plain to the west of the Townsville city and connects as far as Alice River and Black River catchments. The Bohle River catchment is the first coastal stream of the Northern Beaches area of Townsville. The Main source to the Bohle River is the Pinnacle Range which reaches up to 730 m high (Maunsell McIntyre, 2000) . The characteristics of the catchment are rapidly changes due to the westward expansion of Townsville and surrounding residential areas.
Climatic and seasonal changes From WetlandLink • The climatic conditions of the site have been sourced from the Bureau of Meteorology (2009) and show the temperature and rainfall averages distributed over the calendar year. • The highest average temperatures are recorded between December and February reaching 31.4 °C with the lowest temperatures of 13.6°C occurring in July. Rainfall trends mirror the temperature trends showing maximum levels falling in the summer months between December and March with the driest periods occurring in winter months. • The most extreme flood event at Bohle River occurred on January the 10-11, 1998 resulting from ex-tropical cyclone ‘sid’. The ‘sid’ event caused disastrous flooding to all streams between the Bohle River and Bluewater Creek. The total rainfall recorded over the 5 day period was in excess of 1000mm which is close to the Townsville annual average rainfall (Maunsell McIntyre, 2000). Flooding • The Bohle River drains most of the immediate coastal plains immediately west of the Townsville City area and the flood plain adjoining the Bohle River channel is subject to flooding. • Flooding is the result of large scale rainfall events. The Bureau of Meteorology (2008) has provided a rough guide to assessing the likelihood of flooding within the Bohle River Catchment. The guide includes: • Minor to Moderate Flooding: Average catchment rainfall in excess of 200mm in 24 hours may result in stream rises and the possibility of minor to moderate flooding developing in the Bohle River. • Major Flooding: Average catchment rainfall in excess of 400 mm in 24 hours is likely to result in significant stream rises with major flooding for the Bohle River. • The Bureau of Meteorology has been recording flooding events since 1986 and the Bohle River has reached major flooding status five times; 1991, 1997, 1998, 2000 and in 2007. These results would indicate that the Bohle River Catchment reaches a major flooding event every 5.5 years.
Vegetation types From WetlandLink • Based on information sourced through ‘independent studies’ of the region, vegetation communities are characterized by mosaics of vegetation comprised of species tolerant of poorly drained conditions notably Eucalyptus varieties such as the Eucalyptus platyphylla and Eucalyptus crebra woodland varieties. • It is seen that the presence of weed species on the Bohle wetland site can be managed by coordinating various management techniques at crucial times of the year. • Weed species identified for immediate action to be taken on managing their presence include: • Hymenachne amplexicaulis • Cryptostegia madagascariensis • Ziziphus mauritiana • Parkinsonia aculeate • Panicum maximum • See comprehensive species list at http://wiki.wetlandlink.com.au/mediawiki/index.php/Vegetation_types
Bird species From WetlandLink • The Bohle River wetland is one of the best places in Townsville to easily observe local and migratory bird species. In August 2009 there were 57 different bird species identified at the site. The most recent survey in November 2009 found 39 different species however there has been a fire sweep through the area recently which have contributed to the reduction in observed species. The following bird species list is collated from observations between January 2003- November 2009. • See comprehensive bird species list http://wiki.wetlandlink.com.au/mediawiki/images/3/36/Bohle_wetlands_birdlist.pdf
Fish species From WetlandLink • The Bohle River is ecologically and economically significant as it contains large fish habitat areas, important for the fishing industry and the local community. • The Bohle River has some small deepwater perennial ponds and natural riparian vegetation in its middle reaches (figure 34). Schools of mullet and tarpon have been observed and the area is used by juvenile barramundi. Further upstream, fish become stranded in the pools during prolonged dry periods and fish rescues by Sunfish have included the above species as well as mangrove jack and some freshwater species including rainbow fish, flyspecked hardyhead and empire gudgeons. Upstream impacts include improved drainage and past inputs from a secondary treated sewage treatment plant that has recently been upgraded to tertiary treatment. In-stream impacts include nutrient run-off from both the sewage treatment plant and residential areas, invasive aquatic weeds such as pistia, water hyacinth and para grass. The water quality remains acceptable for fish and the area is important remnant in-stream habitat within the district (Lukacs, 1996). Tilapia are known to inhabit some section of the river (pers obs Veitch). Risks or threats to the Bohle River: • 1. Urban development as Thuringowa City expands. • 2. Changes to river hydrology from urban and industrial development. • 3. Invasive aquatic weeds including pistia, water hyacinth and para grass. • 4. Tilapia and potentially other non-native fish species.
Revegetation Project Conservation Volunteers Australia looks to maximize the involvement of community based volunteering in long term rehabilitation efforts at the Bohle site. Primary activities focus on the implementation of on-ground works to reduce the presence of invasive weed species in order to revegetate the riparian corridor and wetlands. This will significantly increase biodiversity, wildlife habitat as well as reduce the potential of fires. • On ground activities include: • Removing various weed varieties; Class 2 Weeds of National significance as well as herbaceous and understorey species. Methods implemented to remove these weed species consist of an integrated approach and include hand pulling, brush cutting, applying herbicides and increasing competition through planting. • Revegetation activities focused on increasing plantings around the wetland body that include major plantings of over 10,000 native plants. • Environmental monitoring; data is collected on a variety of environmental indicators that reflect the impacts of CVA’s work including flora surveys, bird surveys as well as physio-chemical water quality testing, macro-invertebrate surveys and fish sampling. • The project involves community education and interpretation to promote the values of the site and to contribute to project outcomes. Community members are welcome to volunteer to protect and restore the Bohle Wetlands site every Wednesday and every second Sunday. Come along and see the great progress that has been achieved since May 2005. For more information on how to get involved in volunteering or site information please contact Scott Fry on 0427 533 002 begin_of_the_skype_highlighting 0427 533 002 end_of_the_skype_highlighting or sfry@conservationvolunteers.com.au.
Problems facing the Bohle Wetlands In the freshwater sections, weed invasion, particularly rubber vine and chinee apple, but also aquatic weeds such as Pistia stratiodes (pistia) and Eichhornia crassipes (water hyacinth), has degraded the aquatic habitat. Rubbish is extensive, soil erosion is prevalent, riparian vegetation has been cleared, and pollutants from upstream (e.g. a sewerage treatment plant) is resulting in the eutrophication of the river. A large wet season flush will improve the waterway, but ongoing pollution and degradation by weeds and erosion (riverbank, sheet and rill) will continue. In the tidal reaches, stormwater from industrial developments, the clearing of riparian zones, illegal boat access points, fishing pressures, weed invasion and soil erosion have similarly resulted in the degradation of the river. Recent land subdivision in the catchment (e.g. "Willows") and future development (e.g. the Woolcock St extension) is likely to place further pressure on the river, with increased surface drainage and land clearing changing the catchment’s characteristics (e.g. hydrology, water quality). However, given the current poor state of the river, there may be some benefit derived from catchment development. If the TCC and TSC can guide development with the goal of also improving the Bohle River (through implementing weed control and tree planting programs, providing adequate riparian buffers for the river, installing pollution mitigation devices such as litter traps and constructed wetlands, and developing a sense of community ownership of the resource), a net gain can be made from further development. Conversely, if development proceeds without such goals in mind, the risk of completely degrading the river’s natural values is high.
General Information of Bohle wetland -Wetland Habitat Pro-forma Wetland Sample Site 1.5 Bohle River - near Woolcock St extension Grid Reference No. DU692684 Wetland Type Classification (after Blackman et al., 1992) Simple wetland aggregation Biogeograhic Region Brigalow Belt (North) Land System Landform Pattern/Element Ecological System/Subsystem Riverine/Lower perennial Class/Subclass Aquatic Bed/Floating vascular Dominance Type Pistia stratiodes Water Regime Intermittently exposed Water Chemistry Fresh Soil Organic Special Modifiers Associated vegetation Eichhornia crassipes, Salvinia molesta Size channel ~ >10m Management Issues Exotics, eutrophication, fire, litter Conservation Value Low Recommended Action 1. Investigate possibility of rehabilitation (e.g. litter clean-up, weed control) 2. Seek advice on biological control of floating exotic species. 3. Improve water quality through adequate wastewater treatment and stormwater management
General information of Bohle River • Wetlands of the TCC LGA: Report No.96/28 • Australian Centre for Tropical Freshwater Research Page 21 • Wetland Habitat Pro-forma • Wetland Sample Site 1.4 Bohle River - downstream of Bruce highway • Grid Reference No. DU697718 • Wetland Type Classification • (after Blackman et al., 1992) • Simple wetland aggregation • Biogeograhic Region Brigalow Belt (North) • Land System • Landform Pattern/Element • Ecological System/Subsystem Estuarine/Intertidal • Class/Subclass Streambed/Mud • Dominance Type Avicennia marina • Water Regime Regularly flooded • Water Chemistry Mixohaline • Soil Organic • Special Modifiers • Associated vegetation Bruguiera sp.,Ceriops tagal • Size channel ~ <20m • Management Issues Streambank erosion, fishing pressure, exotics, • access tracks • Conservation Value Low-Medium • Recommended Action 1. Implement water quality monitoring program. • 2. Investigate possibility of rehabilitation (e.g. • litter clean-up, weed control) • 3. Establish management plan in conjunction with • stakeholders (e.g. DoE, landholders) • 4. Conduct fish surveys to determine populations • and sustainable harvest levels.
Townsville City Council Meeting Scenario:- The Townsville City Council has received plans for a development project on the Bohle Wetlands. It includes a set of units overlooking the wetlands and a cultural centre for visitors. This centre will inform tourists and locals of the importance of protecting these wetlands, explain its indigenous significance and provide guided tours. The class will be divided into the following groups:- Conservationists- want no development- leave the wetlands untouched Developers- want to build unit complex overlooking the wetlands Aboriginal Elders-want cultural centre to explain cultural significance Recreation Users-want areas for controlled fishing, swimming and picnicking Your group must 1. Brainstorm and record points supporting your lobby group and also record points others might raise to defeat your cause ( so you are prepared to argue against them). Elect 1-2 spokepersons. All have notes ready to support your case. At the meeting write down notes to defend your position and be prepared to speak when the floor is ‘opened ‘ for debate. 2.The meeting will follow the format of the mayor putting forward the proposed development and then 1-2 persons (elected) from each group will have their say for 3 mins. The floor will then be opened for debate and the mayor will call upon members with their hands up to add to the debate. Order will be controlled by the mayor and he/she will ensure fair arguments from all sides involved. No speaker can talk for more than 2 mins at this time. 3. The mayor and 6 councillors will be from another class. At the end of the meeting they will have a secret vote to decide what development, if any, should occur.
Townsville City Council Meeting Lobby Group: _______________ Members in the group: ________________________________________________ Your proposal for the Bohle Wetlands: ____________________________________ Elected spoke persons:_______________________________
