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

Abstract

Abstract:In large cities, rainwater tanks are used to save mains water, but in peri-urban and rural areas, rainwater tanks are used as a sole water supply for many households, as these regions often do not have any other means of water supply. This paper investigates the performance of a rainwater harvesting system (RWHS) in peri-urban regions of Greater Sydney, Australia. Considering the daily rainfall data over the entire period of record at ten different locations, it has been found that a 5 kL tank can meet 96% to 99% of the demand for toilet and laundry use depending on the location in Greater Sydney regions. However, in the driest year, a 5 kL tank can meet 69% to 99% of toilet and laundry demand depending on the location. Based on the results of life cycle cost analysis, it has been found that a 5 kL tank has the highest benefit-cost ratio (ranging from 0.86 to 0.97) among the eight possible tank sizes examined in this study. Interestingly, for a 5 kL tank, with a combined use (i.e., toilet, laundry and irrigation), the current water price in Sydney needs to be increased by 3% to 16% to achieve a benefit-cost ratio exceeding one. A set of regression equations are developed which can be used to estimate reliability using the average annual rainfall data at any arbitrary location in the peri-urban regions of Greater Sydney. The method presented in this paper can also be applied to other Australian states and other countries to estimate water savings and reliability of a RWHS using daily rainfall data. OPEN ACCESSWater 2014, 6 946

Economic Analysis and Feasibility of Rainwater Harvesting Systems in Urban and Peri-Urban Environments: A Review of the Global Situation with a Special Focus on Australia and Kenya

“…For example, in Australia from December to February, Perth has less than 6 days with more than 1mm of rainfall [49]. In Sydney, Mean Annual Rainfall (MAR) varies from 743 mm in Campbelltown to 1325 mm in Hornsby [24], only about 50 km away. In Kenya MAR ranges from 760 mm+ on the coast to 1780 mm+ in the highlands and less than 250 mm in the northern desert areas [104].…”

“…They also proposed constraints for the use of hourly, daily and monthly time intervals based on the storage fraction of the RWH system (a function of roof area, tank size and annual rainfall). Daily, let alone hourly data, however, is not always available, and for ease of calculation Hajani et al [25] developed a set of regression equations using MAR data to estimate reliability and water savings anywhere in the peri-urban regions of Greater Sydney, Australia. Developments in satellite estimation of rainfall data where there is little or no ground data available [107][108][109][110] may also become a powerful tool in estimating potential yield, water savings and hence financial viability of a RWH system.…”

“…Londra et al [105] made a comparison between the daily water balance method and the dry period demand method, which is based on meeting demand for the longest annual average dry period, and found that in all cases studied, the dry period demand method leads to a smaller tank. Hajani et al [25] used a daily time step to build a water balance simulation model and noted that the type of behavioral model used could also affect yield-i.e., that the yield-before-spillage (YBS) could overestimate the water savings by 10%-15% in comparison to a yield-after-spillage. After detailed behavioral analysis Fewkes et al [106] advised using the Yield-After-Spillage (YAS) model for design because it gives a conservative estimate.…”

Performance of a RBSN under the RCP Scenarios: A Case Study in South Korea

“…Therefore, similar approaches have been applied to determine the optimal-sizing of a rainwater storage system, such as an analytical equation for storm-water detention [10], a general storage-reliability-yield (SRY) relationship [11], and a method with different results depending on the scenario [12], or a dimensionless method [12]. On the other hand, the regional performance of RWHS has drawn great attention as it is necessary to comprehend how regional characteristics, such as social and natural components, affect the performance of a RWHS [13][14][15][16][17].…”

Assessing Marginalized Communities in Mexico for Implementation of Rainwater Catchment Systems

“…Experience using DRWHS varies largely from country to country, from local initiatives by users or fiscal incentives for new buildings to large national programs or even programs in small islands lacking other water resources [1,[13][14][15][16][17][18][19][20]. In this case, this research aims to establish a methodology that helps to identify municipalities with the greatest potential for using this technology and promote further implementation of national public policies in support of communities lacking water services.…”