MAKING THE MOST OF WATER RESOURCES AS FEATURED IN AUSTRALIAN CONSTRUCTION FOCUS - JUNE 2012 EDITION

Transcription

1 MAKING THE MOST OF WATER RESOURCES AS FEATURED IN AUSTRALIAN CONSTRUCTION FOCUS - JUNE 2012 EDITION

2 2 JUNE ISSUE 2012

3 AUSTRALIAN CONSTRUCTION FOCUS 3 Making The Most Of Water Resources Mitchell Water Conserving and managing water is one of the greatest challenges facing Australia today, according to Melbourne-based Mitchell Water. The company has worked hard over the years to become Australia s premier dedicated water pipeline design and construction contractor... By John Boley Water is our most precious resource, says Mitchell Water, which lays claim to the title of Australia s largest dedicated water pipeline contractor. The company, with its head office in Melbourne, has the capacity to perform the design, survey, environmental and cultural management as well as the construction of pipelines, water storages, pump stations, controls and communications. Conserving and managing this resource is one of the greatest challenges facing Australia today, according to the company. Mitchell Water has worked hard over the years to become Australia s premier dedicated water pipeline design and construction contractor. We understand the importance of achieving defined targets in terms of cost, time and quality. We are dedicated to assisting our clients in obtaining access to, or disposal of water and ensuring the highest standards of construction whilst minimising impact on the natural environment, our client s activities, landholders and the greater Australian community. Over the past 30 plus years of operation Mitchell Water has delivered many firsts in terms of new machines and procedures. The nature of the pipeline business dictates that innovation is needed to stay ahead of the competition as well as meet targets without adversely affecting the environment, safety of employees and the general public while also not reducing the level of quality of constructed works. Over the past 30 plus years of operation Mitchell Water has delivered many firsts in terms of new machines

4 and procedures for pipeline installation. One such innovation is the patented bedding and padding system. This unique system enables Mitchell Water to use primarily excavated materials and not have to import materials. The system allows the excavated sub-soil to be sieved to the required particle size and placed around the pipe as padding and bedding material. The Wimmera Mallee Pipeline Project has been the largest water distribution project in Australia s history... By their very nature, long distance cross country pipelines can have an enormous impact on the environment and cultural heritage of an area. With this mind Mitchell Water has always been at the forefront of effectively managing the environmental and cultural integrity of the areas in which it works. Mitchell Water is accredited to ISO and its Environmental Management System is constantly evolving to meet current best practice, and adapting to deal with changing

5 EQUIPMENT IN-HOUSE Mitchell Water s impressive equipment roster includes roundabout trenchers developed and patented by Mitchell Water Australia. They are up to 300 mm wide and 1200 mm deep for neat, narrow trenching through clays and rock. They produce a powder fine material, possess high production rates and are GPS guided for horizontal and vertical grading. Modified Vibratory Ploughs, also developed by the company, feature trenchless construction, can install HDPE up to 125 mm diameter and 1200 mm deep, require no surface grading, cause no soil erosion or sinkage, are GPS guided for horizontal and vertical grading and are ideal for sensitive areas or protected vegetation. The Swiftpipe, as the modified vibratory plough is known, is able to work from 600 mm minimum cover down to 1.4 metres deep. The current Swiftpipe plough can plough from 63 mm pipe up to 315 mm pipe. Smaller diameters come on rolls, but once the pipe diameter exceeds 125 mm we use butt fusion welding to string lengths together and plough it in just the same as if it was on a roll. The Swiftpipe was a great asset during construction of the Wimmera Mallee Pipeline, with over 2,000 km of pipe laid using the Swiftpipe method; proving its advanced vibratory technology not only increased the speed of construction, but also contributed to reduced costs and adhered to the strict environmental protection requirements. The company also has many Bucket Whee l Trenchers and Vermeer Trenchers, which provide the backbone for larger diameter projects. Mitchell Water has recently imported new hydraulic trenching machines to make the fleet even more efficient and flexible. Trenchers are fitted with fully automated GPS level and grade controls.

6 environmental conditions. A case in point was the massive Wimmera Mallee Pipeline Project, where Mitchell Water encountered and appropriately dealt with more than 1,600 ecological and cultural hold points and over 300 waterway crossings. Through preventative actions and well structured work practices the majority of these areas have often been restored to better than their original condition, according to the company, with no real evidence of a pipeline ever having been constructed through them. Many of the hundreds of cultural heritage sites which we managed had previously been unidentified. The Wimmera Mallee Pipeline Project has been the largest water distribution project in Australia s history. The pipeline system will supply 9,000 rural properties and 36 towns over an area of two million hectares, enabling sustainable management of water resources for the large agricultural region of Western Victoria. The initial proposal was for all seven Supply Systems to be completed over a 10 year time frame starting in 2006, but due to the continuing drought conditions and regional water storage capacities dropping below 10 per cent for several years, the project was fast tracked and completed within four years. Mitchell Water Australia was awarded five of these seven contracts. The company had many challenges to overcome, including major river crossings, a large number of cultural heritage sites and thousands of landholders with whom to liaise. All these challenges were managed, Mitchell Water reports, with great success, and the company duly received commendations from the Department of Primary Industries, the local Land Councils and the client. The scope of works for Supply System 1 & 7 included design and construction of approximately 1,400 km of MSCL and PVC pipelines ranging from 1,016 mm to 50 mm, nine pump stations, eight water storage tanks and four earthen storages. To ensure quality results on such chal- SALT INTERCEPTION In mid-2009, Mitchell Water won a contract from SA Water on behalf of the Murray-Darling Basin Authority to construct the Murtho Salt Interception Scheme Disposal and Collector Mains, one of a series of such projects. The groundwater pumping to a salt management basin project entails approximately 38 kilometres of PVC and PE pipelines ranging from 250 mm to 400 mm diameter and associated fittings, and was due for completion this year. River Murray Operations is responsible for ensuring the River Murray s water resources are maintained and enhanced through the efficient operational management of Salt Interception Schemes. SA Water manages these schemes on behalf of the Murray-Darling Basin Authority. Salt interception schemes are large-scale pumping schemes that divert saline groundwater and drainage water before entering rivers. In most cases, a bore and pump system extracts the groundwater and pumps it to a salt management basin some distance from the river. Salt is a natural part of Murray-Darling Basin landscapes and rivers. The groundwater systems close to the River Murray hold more than 100,000 million tonnes of salt. The salts come from the weathering of rocks, from ancient oceans and from salts deposited by rainfall (cyclic salt) over millions of years. All of this salt must necessarily find its way into the river before reaching the sea; typically the river delivers around two million tonnes of salt per year to the sea. The Basin s flat terrain, low rainfall and high evaporation rates contribute to increased salt concentration across the landscape. Land clearing and irrigation has increasingly mobilised salt (into the landscape and river systems). Compounding this has been the increasing proportion of river flows being diverted for irrigation, industrial and urban uses. There is now less flow in the river to dilute inflows of saline groundwater. Since 1988, New South Wales, Victoria and South Australia, together with the Australian Government, have funded the construction of salt interception schemes that prevent approximately half a million tonnes of salt from reaching the River Murray every year. Salt interception schemes, together with other actions such as improved irrigation practices and river dilution flows, have reduced the salinity in the River Murray by approximately 200 EC (Electrical Conductivity, a measure of salinity) per year at Morgan in South Australia.

7 lenging projects, Mitchell Water maintains its own fleet of trenching, pipe installation and backfilling equipment which has been specifically developed for use in constructing water infrastructure, some of it to unique and patented designs. Mitchell Water maintains its own fleet of trenching, pipe installation and backfilling equipment which has been specifically developed for use in constructing water infrastructure. For example, the company says its pipe bedding screening and compaction equipment offers enormous cost savings and environmental, health and safety benefits. Ownership of the plant and equipment gives Mitchell Water the flexibility, and our clients the assurance, that each project can quickly draw on the plant most suited to the conditions to optimise the work practices, therefore achieving the highest possible production rates and earliest completion of the project. Mitchell Water

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