Water Journal : Water Journal August 2011
technical features 78 AUGUST 2011 water hydraulics refereed paper Field-test results demonstrate that the basic model is shown to lose considerable prediction accuracy, particularly the negative surge pressure wave at Shaft 11C. However, as the magnitude of the negative surge pressures predicted at WP0369 are quite comparable, it does demonstrate that such a model is suitable to approximate surge mitigation requirements prior to further detailed refinement. Conclusions The key conclusions are: • It is feasible, at least in a system dominated by large surge mitigation devices such as the surge vessels in this system, to have a highly simplified model capable of determining reasonably accurate solutions to feed into more detailed analysis. • Significant efficiencies can be obtained without significant loss of accuracy by utilising a properly simplified model of a complex and computationally demanding system, provided it is understood how a simplified model might achieve appropriate results, and a robust procedure is undertaken to ensure compatibility. • Proper software selection is important, and consideration should be given to the required functionality. For example, in this case the complexity of the network and the compatibility of HAMMER and HYTRAN with InfoWorks via EPANET made them the most suitable tools for the work. While WATHAM was a highly useful water hammer program for simpler systems, at the time the work was undertaken it was unsuitable for such a complex network. • It is demonstrated that a simple model (such as WATHAM) provides an experienced engineer with a method to verify more detailed surge modelling results. • It has been demonstrated that modelled results are compatible across software packages; however, there are significant advantages to some applications (HAMMER in this case), particularly with a detailed multiple scenario system such as this, in having a model that performs both a steady state solution and the associated transient analysis. Models not capable of this require some effort in developing a steady state solver and an intermediate method to import that data into the transient model. • The results from the cut-down models in both HAMMER and HYTRAN are consistent with results of the field testing. This should provide confidence that desktop water hammer studies will match transient events that may occur as a result of operation or equipment failure. Disclaimer These materials contain information of a general nature and are provided for discussion purposes only. The conclusions drawn are specific to the circumstances of this project only and should not be taken in any way as representing engineering or procurement advice. KBR does not warrant the accuracy, completeness or currency of the information in these materials. Any person who uses or relies on these materials does so entirely at their own risk. Acknowledgements The authors would like to acknowledge the design input, review and support of several SWC and WDA staff, notably: Robert Lus, Christopher Moore, Paul De Sa and Bruce Maunder, all of SWC. The Authors Robert Wilson (email: robert.wilson2@ kbr.com) is a Principal Water Resources Engineer and Project Manager in KBR's Sydney office. Kresho Zic (email: kreho. firstname.lastname@example.org) is KBR's Chief Technical Advisor for Water Resources and is based in the Perth office. Ben Leonard is a Mechanical Engineer based in KBR's Perth office. References Bentley Systems, 2008: Bentley HAMMER V8 XM Edition User's Guide, Bentley Systems Incorporated, Haestad Methods Solution Center, Watertown, CT, USA. Lawgun N, 2008: Hytran Water Hammer Software Manual, Hytran v3.7.1-5, Hytran Solutions, Pakuranga, Auckland, New Zealand. Sydney Water, 2010: Quarterly Drinking Water Quality Report, 1st July 2010 to 30th September 2010, Version 2. presented at Roof Water Harvesting means rain water is harvested from rooftops in new residential subdivisions and transported through pipes to an existing raw water storage. From there it is treated and becomes part of the drinking water supply. The Warrnambool demonstration site is located at Russell Creek Residential Estate, on the corner of Whites and Aberline Roads, and at the Marrakai Estate on Wangoom Rd. • The project is believed to be the frst of its kind in Australia. • It provides a working demonstration of a more sustainable approach to water management by using the new catchment" of roof area created in population growth areas. " ROOF WATER HARVESTING ...because it's too good to waste! TMB 8294 Roof Water Harvesting Toolkit Interested in Roof Water Harvesting in your area? Log on to www.wannonwater.com.au or call 1300 926 666 to request a toolkit. Funding has been provided through the Australian Government's Water for the Future initiative and the Victorian State Government, allowing the demonstration site to be established and the regional harvesting principle to be explored in other areas of Australia.
Water Journal September 2011
Water Journal July 2011