Implications to stormwater management as a result of lot scale rainwater tank systems: a case study in Western Sydney, Australia

Abstract

Rainwater tanks are increasingly adopted in Australia to reduce potable water demand and are perceived to reduce the volume of stormwater discharge from developments. This paper investigates the water balance of rainwater tanks, in particular the possible impacts these tanks could have in controlling the stormwater discharge volume. The study collected water quantity data from two sites in the Hawkesbury City Council area, New South Wales, Australia and utilised the collected data in a simple water balance model to assess the effectiveness of rainwater tanks in reducing the stormwater discharge volume. The results indicate that a significant reduction in discharge volume from a lot scale development can be achieved if the rainwater tank is connected to multiple end-uses, but is minimal when using irrigation alone. In addition, the commonly used volumetric runoff coefficient of 0.9 was found to over-estimate the runoff from the roof areas and to thereby under-estimate the available volume within the rainwater tanks for retention or detention. Also, sole reliance on the water in the rainwater tanks can make the users aware of their water use pattern and water availability, resulting in significant reductions in water use as the supply dwindles, through self-imposed water restrictions.

Effect of Climate Change on Reliability of Rainwater Harvesting Systems for Kabarole District, Uganda

“…This is within the typical ranges of 0.8-0.95 for roof catchments used in similar studies [12,[25][26][27][28]. However, Van der Sterren et al [29] found out that a runoff coefficient of 0.9 tended to over-estimate the runoff from roof areas, hence the adoption of a runoff coefficient of 0.8 for this study. The roof area was varied in 5 increments from 20 to 200 m 2 .…”

“…This is within the typical ranges of 0.8-0.95 for roof catchments used in similar studies [12, 25-183 28] . However ,Van der Sterren et al, [29] found out that a runoff coefficient of 0.9 tended to over- Harvested runoff volume was estimated as:…”

Reliability and Cost Analysis of a Rainwater Harvesting System in Peri-Urban Regions of Greater Sydney, Australia

“…They carried out the financial viability analysis of the RWHS in single and multi-family buildings and found that in single-family households, an expected payback period would be between 33 and 43 years depending on the tank size, and for a multi-family, building a payback period would be as high as 61 years for a 20 m 3 tank. In Australian studies by van der Sterren et al [10][11][12], it was found that although RWHS would be very useful in providing required water in peri-urban regions of Sydney, water quality would not always meet the required standard in relation to heavy metals and pathogens.…”

Recent Advances in Modelling and Implementation of Rainwater Harvesting Systems towards Sustainable Development

“…In remote regions, RWH contributes towards meeting one of the targets of Sustainable Development Goals (ensuring availability and sustainable management of water and sanitation for all). In urban areas, the rainwater harvesting (RWH) system is generally used as an alternative water supply means for the non-potable purposes (e.g., toilet flushing, laundry, irrigation and car washing), and for control of stormwater [3,4]. The RWH system is also used as a water source for small scale agricultural needs in both urban and rural areas.…”