# Formation Mechanism and Response Strategies for Urban Waterlogging: A Comprehensive Review
## 3 Analytical Framework
### Theoretical Research  
The issue of urban waterlogging is becoming increasingly severe, and with the acceleration of urbanization, both the frequency and intensity of urban waterlogging are rising steadily. Relevant scholars have primarily focused their theoretical research on urban waterlogging mechanisms [27; 28; 29; 30; 31; 32; 33; 34], prediction models [35; 36; 37; 38; 39], risk assessment, and response strategies [28; 40; 41; 42; 43; 44; 45]. The following Sections will summarize the relevant theoretical research from these aspects. Figure 3: Percentage of different research methods. Figure 2: All articles cited from 1996 to 2024. 3.1.1. Mechanisms and Influencing Factors of Waterlogging  
The mechanisms are complex, involving various dynamic interactions, and are closely related to the process of urbanization. According to existing studies, the formation mechanisms of waterlogging can be analyzed from aspects such as land-use changes and drainage system capacity. During urbanization, changes in land use, such as the increase in impermeable surfaces, have significantly altered regional hydrological characteristics, leading to an increased risk of waterlogging. [PERSON] et al. [27] combined remote sensing and GIS technology to study the impact of urban growth on surface runoff in the Pearl River Delta. Their findings indicated that from 1989 to 1997, the annual runoff depth in the Pearl River Delta increased by 8.10 mm, exacerbating the risks in the region. [PERSON] et al. [28] found that urban expansion significantly increases the risk of urban waterlogging, emphasizing the importance of adaptive measures and spatial planning. [PERSON] et al. [29] demonstrated that land occupancy has a substantial impact on water flow resistance, quantifying the effect of increased obstacles on resistance coefficients. In highly urbanized areas, dense buildings lead to increased flow resistance coefficients and reduced water flow speeds, further worsening waterlogging conditions. Changes in flow characteristics may cause rainwater accumulation, especially in areas with insufficient or poorly designed drainage facilities. This phenomenon is particularly pronounced in urbanized regions. The mechanisms of urban waterlogging caused by rainfall and flooding factors are illustrated in Figure 5. [PERSON] et al. [30] and [PERSON] et al. [46] analyzed the impacts of global climate change and urbanization on urban waterlogging in China, proposing prevention and control strategies, such as low-impact development and sponge city construction. Figure 4: Visualization of Key Areas in Urban Flooding Research. The increase in waterlogging events is not only influenced by urban expansion but is also a result of climate change. [PERSON] et al. [31] assessed the impact of climate change on urban waterlogging in Beijing, with results indicating that waterlogging will worsen, emphasizing the need to consider the uncertainties of climate change in the design of prevention and control measures. [PERSON] et al. [32] used the regional climate model RegCM4.6 and the annual maximum method to simulate rainfall changes, concluding that climate change will exacerbate waterlogging and recommending that the design of urban drainage systems take extreme rainfall into account. Additionally, factors influencing waterlogging include the coverage and layout patterns of green infrastructure. [PERSON] et al. [33] analyzed urban governance documents, noting that cities are gradually adopting socio-ecological elements, such as floodplain restoration and green infrastructure, to enhance resilience against future extreme floods. [PERSON] et al. [34] studied the effects of green stormwater infrastructure on reducing urban rainwater runoff and found that distributed green infrastructure systems are more effective than centralized structures, significantly lowering runoff ratios, peak flow rates, and flicker indices, thereby providing new ideas for urban waterlogging management.