Author(s): T. Moriyama; K. Morishita; S. Izumi; K. Nishiyama; R. Watanabe; Y. Musashi
Linked Author(s):
Keywords: Smart rainwater tank; Rainwater grid; Urban river; Flood control
Abstract: The rapid expansion of urban areas has resulted in widespread forest and paddy field destruction that increases the risk of flash flooding at times of heavy rainfall. However, it is difficult to construct dams or huge rainwater storage facilities in some catchment areas. In response to this, we propose the use of smart rainwater tanks (SRTs) equipped with water level sensors, outflow monitoring, and water pump controls. In our design, SRTs will be connected via a network that will make it is possible to collect monitoring data and issue pump control commands to individual tanks. These connected tanks will make up a rainwater grid system (RGS). When a flood warning is issued by self-organized map (SOM), which is one of pattern recognition techniques, issues a flood warning, a pre-discharge command is sent to this RGS after which the pumps of each smart tank will automatically begin discharging stored water to free up space for impending rainfall. We intend to install this system in the Hii River Basin of Fukuoka City, Fukuoka Prefecture, Japan where 106 200-liter tanks have already been installed for flood control purposes. These 200-liter tanks are capable of slightly reducing water levels on the river channel at the peak times of heavy rainfall and are also suitable for use in our grid system experiment. Since residents cannot be relied upon to perform pre-discharges at the appropriate time, this 106-tank system will be equipped with an automatic pre-discharge function. Additionally, collected data will be gathered via an Internet cloud system that will allow residents to comprehend how the RGS is functioning and how much rainwater has been captured. It will also be possible to monitor rainfall amounts using this RGS since it functions as a high-density rain gauge. This is important because rains over 100 mm/hr sometimes cause serious attenuation of the reflectivity of rainfall cell monitored by X-band multi-parameter weather radar networks such as the XRAIN network operated by the River Bureau of the Ministry of Land, Infrastructure, Transport and Tourism (MLIT). A prototype SRT system has been installed at Oginoura Garden Suburb, which is a maisonette-type housing complex, where its functions are now being tested. The SRT system makes it possible to monitor the water level of rainwater tanks, used water quantities, and water discharge amounts. The SRT system can also control water discharge amount by operating pumps via the Internet. Because this type of RGS is expected to be integrated with smart meters and treated as a part of the smart house, smart city, and smart grid concepts, this research can be seen as representing a first step toward achieving those future goals.
Year: 2014