In the heart of China’s Greater Bay Area, a battle is unfolding between urban development and natural hydrology. As cities expand, the delicate balance of water flow, infiltration, and evaporation is disrupted, posing significant challenges for water resource management and flood mitigation. A recent study led by H. Liu from the University of Hong Kong’s Department of Civil Engineering sheds light on how topography and land use changes are reshaping hydrological processes in adjacent watersheds, offering crucial insights for the energy sector and urban planners alike.
Liu and his team developed an integrated surface-subsurface hydrological model using the Simulator for Hydrologic Unstructured Domains (SHUD) to compare two subtropical watersheds with distinct terrain and land cover. The model, calibrated with real-world data, simulated various hydrological processes, providing a comprehensive view of water movement and its response to changes in slope and urbanization.
One of the key findings is the significant impact of slope on hydrological processes. In mountainous areas, the correlation between slope and annual surface runoff, infiltration, and subsurface flow is consistently high. However, at lower elevations, the relationship weakens, indicating that other factors come into play. “In flatter watersheds, the rise in surface runoff is proportionally less than the increase in impervious areas,” Liu explains, highlighting the buffering capacity of these areas against urbanization. But this capacity is not infinite. As annual rainfall intensity increases, so does the vulnerability of these watersheds.
For the energy sector, these findings are particularly relevant. Urbanization often goes hand in hand with increased energy demand, and understanding how water resources are affected is crucial for sustainable development. As Liu points out, “coordinating land use planning and water resource management is essential for mitigating flood risks and ensuring sustainable development.” By providing a robust analysis of land use and land cover change (LULCC) effects on watershed hydrology, the Integrated Surface-Subsurface Hydrological Model (ISSHM) enables predictive approaches to optimizing urban management.
The study, published in Hydrology and Earth System Sciences (Hydrologie und Erdsystemwissenschaften in German), underscores the importance of considering both topography and land use changes when planning urban development. As cities continue to grow, so too will the demand for water and energy. By understanding how these factors interact, we can better prepare for the challenges ahead and ensure a more sustainable future.
The research by Liu and his team is a significant step forward in this direction. By providing a detailed analysis of hydrological processes in response to LULCC, the ISSHM offers a powerful tool for urban planners and energy sector professionals. As we look to the future, this kind of interdisciplinary research will be crucial in shaping sustainable development strategies. The energy sector, in particular, stands to benefit from a deeper understanding of these hydrological dynamics, as it seeks to balance growth with environmental responsibility. The insights gained from this study could inform the design of more resilient infrastructure, the implementation of effective water management strategies, and the development of sustainable energy solutions. As cities continue to expand, the lessons learned from these two adjacent watersheds in the Greater Bay Area could resonate far beyond their borders, influencing urban planning and water resource management on a global scale.
