Improving the Multi-Objective Performance of Rainwater Harvesting Systems Using Real-Time Control Technology

Abstract

Abstract:Many studies have identified the potential of rainwater harvesting (RWH) systems to simultaneously augment potable water supply and reduce delivery of uncontrolled stormwater flows to downstream drainage networks. Potentially, such systems could also play a role in the controlled delivery of water to urban streams in ways which mimic baseflows. The performance of RWH systems to achieve these three objectives could be enhanced using Real-Time Control (RTC) technology to receive rainfall forecasts and initiate pre-storm release in real time, although few studies have explored such potential. We used continuous simulation to model the ability of a range of allotment-scale RWH systems to simultaneously deliver: (i) water supply; (ii) stormwater retention; and (iii) baseflow restoration. We compared the performance of RWH systems with RTC technology to conventional RWH systems and also systems designed with a passive baseflow release, rather than the active (RTC) configuration. We found that RWH systems employing RTC technology were generally superior in simultaneously achieving water supply, stormwater retention and baseflow restoration benefits compared with the other types of system tested. The active operation provided by RTC allows the system to perform optimally across a wider range of climatic conditions, but needs to be carefully designed. We conclude that the active release mechanism employing RTC technology exhibits great promise; its ability to provide centralised control and failure detection also opens the possibility of delivering a more reliable rainwater harvesting system, which can be readily adapted to varying climate over both the short and long term.

A Critical Evaluation of the Water Supply and Stormwater Management Performance of Retrofittable Domestic Rainwater Harvesting Systems

“…The metrics chosen for performance analysis evaluated both objectives of the RWH system: water supply and stormwater management. Relevant metrics were taken from Xu et al [11] and represented both volumetric (efficiency) and frequency characteristics. The water supply metrics were as follows:…”

“…The long-term stormwater management of domestic systems designed for water supply is unclear.Other studies have conceptualised the systems' performance through modelling either at an allotment, neighbourhood or catchment scale. Xu et al [11] modelled the ability of three types of allotment-scale RWH systems to simultaneously deliver the dual benefits discussed above in addition to river baseflow restoration. Using a historic 11 year rainfall dataset, they defined six metrics (the efficiency and frequency of water supply, baseflow and retention) to quantify system performance.…”

“…Campisano and Modica [14] illustrated that their mass-balance approach proved unreliable for the evaluation of water supply and retention for small tanks when daily time steps were used in conjunction with high water demand values, concluding that inaccuracies may occur unless higher temporal resolution analyses are adopted. Although an hourly time step is appropriate for retention studies, it does not permit the modelling and interpretation of the detention performance of stormwater management devices [15].In terms of modelling, current research typically utilizes demand that is based on metered or stochastic household data [11][12][13]. This may not be representative of demand from actual RWH systems which might only be linked to one (downstairs) toilet in a household.…”

“…In terms of modelling, current research typically utilizes demand that is based on metered or stochastic household data [11][12][13]. This may not be representative of demand from actual RWH systems which might only be linked to one (downstairs) toilet in a household.…”

Advanced Operating Technique for Centralized and Decentralized Reservoirs Based on Flood Forecasting to Increase System Resilience in Urban Watersheds

“…In addition, NSMs combined with the same type of NSMs (operation technique with operation technique) have been suggested [1,16]. The operation technique applied in this study (mixed NSMs) suggests NSMs mixed with a different type of NSMs (the operation of drainage facilities based on a flood forecasting technique) [17,18]. Table 1 shows the classification of NSMs with RTC in UDSs.…”