What are the main issues and countermeasures for urban rainwater collection?

Rainwater harvesting refers to the purposeful use of rainwater collection equipment within urban areas to convert rainwater into usable water resources and utilize it directly or indirectly. The utilization of urban rainwater resources plays an extremely important role in solving urban water issues and has become a widely-recognized topic of concern across the globe.

Advancing rainwater collection is of great significance and holds immense development potential. Promoting the resource utilization of urban rainwater, an important unconventional water source, can effectively alleviate urban water shortages and the associated ecological environmental issues. China faces severe urban water scarcity, with statistics showing that nearly 400 out of the 657 cities are experiencing water shortages, including 110 cities with severe water scarcity.

In response to the common practice of over-extracting groundwater in water-scarce cities to ensure water supply, numerous solutions have emerged. This over-extraction has led to various ecological issues such as land subsidence, seawater intrusion, and desertification. According to the Ministry of Land and Resources, the cumulative land subsidence in areas exceeding 200 millimeters nationwide covers 79,000 square kilometers, with more than 50 cities experiencing land subsidence, and the area of seawater intrusion exceeds 3,000 square kilometers.

Rainwater collection measures provide water as one of the city's crucial unconventional water sources, promoting the rational utilization of water resources. It not only effectively increases water supply and directly eases the acute water shortage, but also improves the urban ecological environment by nurturing and replenishing the city's groundwater.