Sponge City: Using the “One Water” Concept to Improve Understanding of Flood Management Effectiveness

Abstract

Urban flood-related issues are substantial in China, arising from rapid construction of megacities over decades with insufficient flood control, all being made worse by climate change. Since Sponge City (SC) options are primarily effective at maintaining the water balance at the surface, flooding continues. In response, the One Water concept is used to demonstrate the need to respond to dimensions beyond SC and shown herein to have potential to reduce the impacts of major storms (e.g., suppress 100-year flooding to a 25-year flooding equivalent). However, climate change causes more intense storms, indicating the intensity of the 100-year storm will increase by ~0.23% annually over the next 70 years. Hence, given sufficient SC options, the 100-year storms may only be effectively reduced to a 50-year storm, at best by SC options. “One Water” is utilized as a concept to demonstrate structured thinking about how each dimension of the hydrologic cycle can be employed to consider the degree of interconnection, allowing improved assessment of various components of the hydrologic cycle and SC options. Examples are used to demonstrate how the concept of One Water links the array of components of the hydrologic cycle together, generating a holistic view of urban water resource security.

A Sustainable Environment Requires Sustainable Water – A Review of Some Water Issues to Learn From

“…This results in only minor amounts of irrigation water travelling to deep groundwater, resulting in declining deep groundwater levels. With an improved understanding of the interconnections between various hydrologic components, it is now realized that the practices shown above for extensive irrigation for decades were catastrophically detrimental to local groundwater resources (Jiang and McBean, 2021).…”

“…Further enhancements reflecting components of climate change also need to be considered and incorporated into long-term planning, to ensure the success of the sustainability of water quantity issues can be managed. An important aspect of the One Water approach is that it is an effective means of portraying to politicians/non-technical people as to how the planning elements for the future can be depicted to improve their understanding of how issues need to be addressed (Jiang and McBean, 2021).…”

Perception of sponge city for achieving circularity goal and hedge against climate change: a study on Weibo

“…Nature-based solutions for sponge city have been promoted as sustainable solutions for urban stormwater management and addressing the urban flooding problem (Fu et al, 2022). To improve the assessment of the hydrological cycle and sponge city's options, Jiang and McBean (2021) used the concept of "One Water" to demonstrate structured thinking about how each dimension of the hydrological cycle could be used to study the degree of interrelationships. Some scholars discussed the relationship among water elasticity, resources, treatment, ecology, waterscape and management modules based on sponge cities to solve urban water problems and human livability (Wang et al, 2021a).…”

“Green structures” for effective rainwater management on roads

“…As it is shown, the downpours are one of the most important disturbances. The problem is getting worse due to global warming (Feng Kong et al, 2021;Jiang et al, 2021), which cause more often and strong precipitations. Together with the rapid urbanization (Feng Kong, 2021;Jiang et al, 2021) and, especially, uncontrolled building, the city flooding events occur too often and require special measures.…”