Introduction
The research seeks to establish and explain the possible causes of environmental degradation in in Yarra River, located in Melbourne, Australia.
The river has been diversely affected by human settlement at its banks from its catchment area to the end of its course.
The degradation of the Yarra River started with the clearing of the habitat around the banks followed by mining of gold around 1850’s.
Problem and Aim
Environmental degradation on the Yarra river is caused by both human and natural causes. The research aims to answer the following questions.
(i) What are the likely (or known) water pollution issues in an urbanized catchment that the Yarra River may experience?
(ii) Is there any information (published or unpublished) available on water quality of the Yarra River? Who is managing it and steps taken?
Methods
During the research, secondary methods of data were used ,especially published and unpublished investigations. There have been several researches conducted by government bodies, community development agencies as well as many departments in the universities in Australia.
Data collected from these secondary sources was used to find out what other sources of pollution are at the river Yarra, its management and steps being taken to protect the river from further pollution.
Results
Results from the studies done, show that there has been a significant change in the Yarra River from the 19th century to the present.
The river has been polluted by both natural and human causes.
Human causes are water harvesting, land use change, construction of roads, storm drain water.
Human Causes of pollution
Water harvesting. The upper part of the river provides water to the inhabitants of Melbourne, and has done so since around 1872 (Carroll, 1988).Damming and building of river channels has affected the natural course of the river. The damming prevents flood plains from getting the sediments the biota needs and may also cause salinity that can affect the agriculture.
Land use change. Over the years the people along the river Yarra have cleared natural habitats to allow farming, construction of roads and urbanization.
Construction of building and roads next to the river causes erosion. In case it rains as foundations are dug, silt flow to the river that affects many recreational activities in the river. Symonds (1982)
Faecal contamination causes pollution in the river. This happens when sewage and storm water mixes as it flows into the river. Illegal connections of sewers to drains, causes faecal contamination according to EPA Victoria (2007) screening for faecal contamination in the river Yarra (p. 23).
Untreated Industrial waste dumping in rivers is harmful to the flora and fauna in the river. Heavy metals that are found in these factories are harmful especially since Yarra river is a source of water for Melbourne.
Gold Mining started as early as 1841 according to the Quarterly registrar’s mining report (1876).A lot of heavy metals leaked into the river bed and affect the environment around the river Yarra.
Mercury that was used to separate the gold from the ore, pollutes the river and affects the Aquatic life. According to the Australian Bureau of statistics (2005), there is rising concern over the impact of mining on the natural environment. Mining has lead to a lot of heavy metal presence in the (Bell and Donnelly, 2006).
Agriculture along the river causes pollution. Farm that use pesticides and other chemicals pose a danger to the river health. These chemical are transported to the river through runoff.
Urbanization has caused pollution in the river. Pavements and tarmac in the city makes infiltration of rain water impossible. This water flows collecting household litter, oil/fuel spills from gas stations and parking lots. It also causes acidic rain due to the sulphur deposited in the air from car and factory emissions.
Dredging and bank widening of certain parts of the river for recreation, has interfered with the river course and the aquatic life ( Rutherfurd et al,2000)
Water Quality
The water quality of the river affects the recreational activities that can take place at the river Yarra. This quality is determined by the presence of microorganisms, litter, toxicants and sediments.
The presence of micro organisms like E.coli is an indicator of a pathogen in the water. Studies carried out by EPA Victoria (2007) showed that E.coli was introduced into the river through fecal contamination caused by illegal sewer connections to drain pipes.
Conclusion
The government through the ministry of water has made efforts to rehabilitate the Yarra River. Since 1970’s the river is no longer a dumping site for industrial waste and rehabilitation of the river is underway (Melbourne Water, 2006).
The ministry of water has appointed Melbourne water as the caretaker of river health in Port Philip and Western Port. It has contributed to the research done by EPA on the water quality.
It is amazing that the river that was once considered the damping site and smelly in Melbourne, has been named as ‘’a finalist in one of the world’s top environmental awards, selected from 50 rivers from 20 countries” (Mackay, 2011).The International river prize award names the best river in management and gives recognition for the restoration and sustainable management of the world’s rivers, lakes and wetlands (International river foundation, 2011 p.1).
Recommendations
The Yarra River is managed by various agencies that have different responsibilities. They are; Department of infrastructure in charge of policy coordination for strategic infrastructure along the river. Parks Victoria is in charge of Yarra waterways for recreation and navigation. City of Melbourne reenacts the policies under the council’s act concerning the conservation of the river Yarra. Department of Sustainability and Environment, provides advice on marine conservation and coastal issues.
Littering can be eliminated by placement of recycle bin in places with high number of people e.g. parks, schools, churches. Public education on recycling and use of bins to put the litter.
Better water management as discussed by Stewardson et al (1994) proposes the use of grey water in the household for gardening, porous pavements and storage water tanks to reduce the amount of surface runoff.
References
Australian Bureau of Statistics, (2005) Year Book, Australia, Issue 87, Australian Bureau of Statistics, Canberra.
Bell, F, Donnelly, L,( 2006), Mining and its impact on the environment, Taylor and Francis, London.
Carroll, B.(1988). The Upper Yarra: An illustrated History. Shire of upper Yarra, Yarra junction.
International River foundation,2011.International river award, Web.
Jutson, J. T. (1910). The structure and general genealogy of the Warrandyte goldfield and adjacent country. Proceedings from royal society of victoria,23( N.S), 516-514.
Mackay, H. 2011. Yarra a world-class river. Web.
Marriot, K.L. (1975 ). The Yarra Valley. Melbourne. Sorrette.
Quarterly Registrars mining report ,(1876). Quarterly Registrars mining report. Melbourne.
Rutherfurd, I.D.,Jerrie,K. & Marsh, N.(2000).A rehabilitation Manual for Australian Streams. Land and Water Resource research & development corporation. Melbourne.
Symonds, S. (1982). Healesville: History in the hills. Lilydale, Pioneer design studio.
Tiller, D.(1990). Mercury in fresh water environment: The contamination of water bodies in Victoria as a result of past gold mining activities. EPA report SRS90/005.
Wolman, M.G.( 1967).A cycle of sedimentation and erosion in urban river channels.