Blog Post

Against the backdrop of intensifying global climate change and accelerating urbanization, extreme rainfall events occur frequently, and the phenomenon of "cities turning into 'lakes' after rain" is common. Rainwater is no longer just simple "natural precipitation" but a core issue related to urban safety, ecological health, and resource sustainability. As a systematic solution for overall rainwater management, stormwater engineering planning is by no means a "simple assembly" of traditional drainage facilities. Instead, through scientific layout, technological integration, and ecological coordination, it serves as a crucial link to achieve "orderly drainage, efficient utilization, and ecological friendliness" of rainwater, and its importance has permeated every dimension of urban operation.​

I. Resisting Waterlogging Disasters: Building the "First Line of Defense" for Urban Safety​

Urban waterlogging not only causes traffic paralysis and property losses but also may threaten the lives of residents. Scientific stormwater engineering planning is the core guarantee for resisting waterlogging. In traditional urban construction, the model of "prioritizing above-ground development over underground infrastructure" and "focusing on drainage while neglecting storage" has led to a continuous increase in hardened pavement and a constant reduction in natural infiltration space. Rainwater quickly converges into runoff, far exceeding the carrying capacity of drainage pipe networks. In contrast, professional stormwater engineering planning starts from the full chain of "source emission reduction - process control - systematic management". By accurately calculating the regional rainfall intensity, catchment area, and pipe network load, it rationally arranges source emission reduction measures such as permeable pavement, green roofs, and bioretention facilities, and matches them with process control projects like rainwater storage tanks and flood discharge channels. This builds a drainage system featuring "combination of drainage and storage, and separation of fast and slow runoff", fundamentally reducing the risk of waterlogging.​

Take Shenzhen, a pilot sponge city in China, as an example. Through systematic stormwater engineering planning, a rainwater management system centered on "rain gardens + underground storage tanks" was built in Longhua District. Data shows that when the area was hit by a once-in-50-year rainstorm, the duration of road waterlogging was reduced from 4 hours (before the planning) to less than 30 minutes, and the waterlogging depth was controlled below 15 centimeters, effectively ensuring the normal operation of regional traffic and residents' lives. This case fully proves that stormwater engineering planning can transform "passive flood resistance" into "active defense", building a solid barrier for urban safety.​

II. Activating Water Resources: A "Green Path" to Solve Urban Water Scarcity​

Global water scarcity has become a major bottleneck restricting urban development. However, rainwater, as a clean and renewable water resource, has been seriously undervalued in terms of its recycling potential. Stormwater engineering planning integrates the full-process technology of "collection - purification - reuse", which can convert the previously wasted rainwater into a usable "second water source", effectively alleviating the pressure on urban water supply and realizing the recycling of water resources.​

In the industrial sector, rainwater reuse systems built through stormwater engineering planning can use purified rainwater for workshop floor cleaning, equipment cooling make-up water, etc., reducing the dependence of industrial water use on municipal water supply. According to statistics, a large manufacturing park achieved an annual recycled rainwater volume of 120,000 cubic meters through stormwater engineering planning, accounting for 35% of the park's total non-production water consumption, and saving the enterprise more than 800,000 yuan in water fees annually. In the civil sector, stormwater engineering planning can be combined with the layout of residential communities and public green spaces to use rainwater for green irrigation, road sprinkling, landscape water replenishment, etc. For instance, a residential community in Beijing, through a planned and constructed rainwater reuse system, achieved a 60% proportion of rainwater in its annual irrigation water consumption. This not only reduced the consumption of municipal greening water but also lowered the property management costs of the community. Stormwater engineering planning turns "heaven-sent water" into a valuable resource, providing a practical solution for the sustainable use of urban water resources.​

III. Protecting the Ecological Environment: A "Balancing Link" for Maintaining the Symbiosis between Cities and Nature​

In the process of urbanization, a large amount of hardened pavement has replaced natural vegetation, disrupting the natural cycle of rainwater: rainwater cannot infiltrate through the soil to replenish groundwater, leading to a drop in the groundwater level and soil desertification; at the same time, untreated rainwater runoff, carrying pollutants (such as road oil stains, pesticide residues, domestic waste, etc.), is directly discharged into rivers and lakes, causing water pollution and damaging the aquatic ecosystem. Guided by the core principle of "respecting nature and following nature", stormwater engineering planning restores the urban rainwater cycle and protects the ecological environment by building an ecologically sound rainwater management system.​

In terms of groundwater replenishment, facilities such as permeable pavement and bioretention facilities arranged in stormwater engineering planning allow rainwater to infiltrate slowly into the ground, replenishing groundwater reserves. Data shows that in urban parks, the annual groundwater replenishment volume in areas with permeable pavement is more than 40% higher than that in areas with traditional asphalt pavement, effectively alleviating the problem of declining urban groundwater levels. In terms of aquatic ecological protection, facilities like pre-ponds and constructed wetlands in stormwater engineering planning can filter, adsorb, and degrade pollutants in rainwater runoff, reducing the amount of pollutants entering rivers. For example, around the ancient city moat in Suzhou, a 5-kilometer-long ecological buffer zone and constructed wetland were built through stormwater engineering planning. After treatment, the compliance rate of rainwater quality when entering the river reached 92%, the transparency of the river water increased by 30%, and the number of aquatic organisms such as fish and shrimp increased significantly, effectively restoring the aquatic ecosystem. Stormwater engineering planning ensures that cities no longer "separate" themselves from nature during development but coexist harmoniously with the ecological environment.​

IV. Empowering Urban Sustainable Development: An "Invisible Engine" for Enhancing Urban Comprehensive Competitiveness​

The sustainable development of a city requires not only economic growth but also the balance of environmental quality, residents' quality of life, and long-term development potential. Stormwater engineering planning is an important support for promoting urban sustainable development. On the one hand, scientific stormwater engineering planning can enhance the resilience of urban infrastructure, reduce economic losses caused by issues such as waterlogging and water scarcity, and provide a stable environmental guarantee for urban industrial development. On the other hand, the ecological improvements brought about by stormwater engineering planning (such as more green spaces, clear water bodies, and humid air) can enhance residents' sense of well-being and strengthen the city's attractiveness to talents and enterprises.​

In the long run, stormwater engineering planning can also help cities save a large amount of later governance costs. Under the traditional model, cities often invest funds in reconstruction passively after suffering from waterlogging and water pollution, which is not only costly but also unsustainable in effect. In contrast, stormwater engineering planning avoids problems from the source through scientific early-stage layout, realizing "one-time investment and long-term benefits". For example, a new district in Shanghai carried out systematic stormwater engineering planning at the initial stage of construction. Although the initial planning and construction costs were 15% higher than those of the traditional model, in the subsequent 10 years, the economic losses of this district caused by waterlogging and water pollution were 60% lower than those of unplanned areas, and the benefits brought by water resource recycling increased year by year, showing significant comprehensive benefits. Stormwater engineering planning has become an important indicator for measuring urban governance capabilities and comprehensive competitiveness, injecting sustained impetus into the long-term development of cities.​

Conclusion​

Stormwater engineering planning is by no means an isolated engineering design but a systematic project related to urban safety, resource utilization, ecological protection, and sustainable development. Faced with the dual challenges of climate change and accelerated urbanization, attaching importance to and promoting scientific stormwater engineering planning can not only solve the current problems of waterlogging, water scarcity, and ecological imbalance faced by cities but also lay a solid foundation for the future development of cities. As a professional service provider focusing on the field of stormwater engineering, we have always believed that through precise planning, innovative technology, and high-quality services, every city can have a safer, greener, and more sustainable rainwater management system, safeguarding the resilience and vitality of the city.