July 2010 - Issue #10
Web tool to get us tanked up
Story by Kellie Penfold
View articles in related topics: Sustainability & The Environment
Dr Monzur Imteaz is a glass-half-empty kind of chap. He’s not being unduly negative, he just sees wasted opportunity in not being able to fill to the top.
In particular he recoils at the thought of half-empty rainwater tanks, or worse, tanks that can’t hold any more water, just because there’s no simple tool to help people better match storage with catchment.
Water is again becoming our most precious resource – as it used to be when Australians better understood the realities of living on the world’s driest continent – and collecting urban water, in particular, is likely to become crucial for our fast-growing towns and cities.
Dr Imteaz’s interest in the re-emerging popularity of rainwater tanks – which for a period were actually banned by some municipalities – stems from his research at Swinburne University of Technology’s Centre for Sustainable Infrastructure, where he specialises in the development of stormwater as a resource.
This under-used water source and the commercial, rather than scientific, approach to capturing it is driving Dr Imteaz to develop a number of simple tools, building on the STORMKIT system he has already developed, to analyse and design stormwater systems.
“House tanks are a good example. People want to catch the stormwater collected on their own roofs, but tanks are often installed with little or no planning as to whether they are the right size. There are plenty of tanks that will never fill and there are plenty that are too small to capture all the water which is available,” Dr Imteaz says.
He says engineers and managers dealing generally with water and drainage matters either use tedious manual calculations or sophisticated, large, data-dependent programs to perform stormwater analysis and design. The advantages of a tool such as STORMKIT are its accuracy and simplicity.
STORMKIT was presented and demonstrated at the 32nd Hydrology and Water Resources Symposium, held in Newcastle in November 2009, and is now available to water managers and other users.
Dr Imteaz is now developing an internet-based tool to help householders establish rainfall capture capacity which, with suitable funding to help develop the website, could also be available this year.
Corporate and local government stakeholders regularly employ consultants to analyse the potential water catchment in urban projects, but Dr Imteaz feels that this information – often obtained at a high price – is subsequently used by just a few people, whereas a web-based tool would be available to everyone and could be used over and over again.
Using information such as contributing catchment size, tank volume, geographic location, weather conditions and the water’s intended use, his proposed calculation tool will determine the volume of water likely to be captured each year according to different rainfall scenarios.
He notes that historic rainfall figures are not much help any more. “If you look at Melbourne, it was 650 millimetres for 70 or 80 years. Yet for the past 12 years it has been 360 to 630mm. Therefore, water storages are subject to high rainfall, average rainfall and below-average rainfall.”
Near his office on the university’s Hawthorn campus are two large rainwater tanks with which Dr Imteaz has put his theory into practice, establishing their effectiveness and payback period. Applying his calculations to the capture area, he was able to measure by how much one tank was too large to readily fill, and the extent to which the other was too small to capture all available rainfall.
The point Dr Imteaz makes is that better analysis and design before constructing such facilities would significantly improve their effectiveness and cost-benefit.
Initially, the proposed tool is for stormwater capturing analysis for impervious roofs only. But it can be extended for pervious surfaces (such as golf courses and playing fields) by incorporating soil loss parameters.
While the complete development of the proposed tool depends on the success of getting funds from relevant authorities, Dr Imteaz is moving his focus to fog water – to see what value there would be in harvesting moisture created during foggy weather conditions.
