The international common term for "sponge city" refers to the construction of a low-impact rainwater system, which refers to the cities acting like a sponge, which can absorb, store, infiltrate, and purify runoff rainwater on the spot or nearby when there is rainfall, replenish groundwater, and regulate water circulation. And release, utilize the water under certain conditions like droughts and water shortages, thereby making water migration activities in the city more natural. The core concept of sponge city is to solve flood problems on the spot, using a flexible and recyclable water management method to allow the city to digest rainwater instead of transferring water to other places. The key to building a sponge city is to protect and restore the original rivers, lakes, wetlands, private ponds and other natural "sponges" that have water collection and conservation functions; on the other hand, to create artificial wetlands, rain gardens, and rainwater through scientific planning, and the artificial "sponges" such as sunken green spaces and green roofs store and digest rainwater on site.

The IoT Monitoring System of Tianzheng high tech integrates the concept of smart cities into sponge cities construction. By integrating a variety of new and accurate sensing and measurement equipment, it is reasonably distributed to various "sponge" monitoring sites, using the Internet of Things, cloud Information technologies, cloud platforms, big data, and edge computing, to coordinate the various centralized or distributed energy, green facilities, and sponge city construction facilities, thereby making the construction and management of sponge cities efficient and intelligent.

System composition

The smart sponge city IoT monitoring system consists of four parts: collection layer, transmission layer, application layer and display layer.

Collection layer:

It mainly consists of devices such as flow velocity sensor, water level sensor, rainfall sensor, water quality sensor, infiltration rate sensor, soil moisture sensor, air temperature and humidity sensor, and video capture camera. Its main function is to collect real-time online flow, velocity water level, rainfall, soil moisture, permeability, air temperature, humidity, and the water quality information of the sponge monitoring station.

Transport layer:

Transmission of all collection devices is composed of Lora long-distance wireless communication and GPRS (4G/3G/2G) network. The collection nodes are deployed wireless technology with Lora IoT. The wireless communication distance between the nodes and the central point can reach 2500M-8000M, which can greatly reduce the equipment purchase cost and construction cost of multiple "sponge" monitoring sites in same city or an area.

Application layer:

The intelligent sponge city Internet of Things monitoring system based on "deep thinking brain" is used to monitor, analyze, warn, manage and support decision-making in whole process of the sponge city through cloud platform, big data, edge computing and other advanced technologies. So as to achieve the functions of sponge city performance assessment index evaluation, urban drainage/rainfall online monitoring, flood control emergency command and dispatching decision support, black and odorous water body supervision decision support and sponge facilities joint dispatching decision support.

Display layers:

It is mainly composed of display devices such as LED screens/LCD screens, supporting remote scheduled data updates. Its core function is to quickly and realistically display the operation of smart sponge cities to the public, achieving the purpose of publicity.