Thinking Like a Sponge
Intense weather events are calling attention to not just local but worldwide water crises caused by climate. Coastal inundation, community disruption, dislocation and recovery are problems that we seem increasingly unable to withstand. The concept of “sponge cities” are a revolutionary planning tool to integrate urban design with water management strategies such as ground conditions, road and construction patterns and more, to create responses to rapidly changing coastal conditions.
In the south Atlantic, the coincidence of warm ocean water and humid air temperature, wind and evaporation creates weather phenomenon known as tropical cyclones or hurricanes, enhanced over the past decade by changing climate circumstances into intense weather events that threaten the islands of the Caribbean, the southern eastern coast of the United States, with erratic paths of high winds and seas that inundate, flood, and flatten coastal communities mostly unprotected and today especially vulnerable as these storms increase in strength, frequency, and consequence. Recently, Hurricane Ida provided an exemplary demonstration of the power of such events, to come ashore at New Orleans, move inland, and then north east, to extend its path of devastation and dislocation, millions left without power, coastal communities inundated, and calculations of cost of recovery in the millions.
Ida was a two-headed hydro-event, first as it accelerated in the Gulf of Mexico with its gale force winds and waves, challenging dikes, levees, pumps, and other mitigation protections, and destroying property and people without discrimination. But its second strike was unexpected, and even more destructive, as it passed over New Jersey and New York City without mercy, flooding basements and subway stations, with sudden death for far too many unsuspecting and unprotected. In 2019, Hurricane Sandy had shown New Yorkers what these newly invigorated natural events could do to test protections in the city, after which steps were taken to anticipate and construct additional barriers and systems of protection. Ida proved that this effort was not enough, and shortly after Mayor Bill DeBlasio announced another “plan” as if, too late, he could deny the wind and water that will certainly come as climate impacts continue to be ignored or inadequate.
These important urban centers, built for accessibility to rivers and ports, conducive for trade and as centers of industry, are no longer safe and secure: fishing facilities and grounds, coastwise manufacturing, industry, and refining, urban and sub-urban communities existing often at or even below sea level are simply not able to withstand the power of these natural event, even more so should frequency and intensity of climate-induced storm and sea level rise continue to amplify as predicted.
What to do? What do these new evolving conditions imply for the future. How does salt water inundation and flood affect underground freshwater aquifers, infrastructure maintenance and improvement, the financial and social viability of an economy at risk by new water conditions, patterns, and succeeding events? It is going to demand an entirely new level of analysis and planning, construction methods and materials, and innovation to contain, treat, and otherwise manage the hydraulic organization of every community. To not do so, with the evidence provided by Katrina and Ida, is an irresponsible step toward decline.
These problems are not exclusive to the eastern United States, but are part of a worldwide water crisis caused by climate, yes, but also by unsustainable consumption, irrigation, pollution, and all the other challenges to hydraulic society.
Enter the simple sponge, an ubiquitous marine organism, asymmetrical and varied, a living entity adapted for the maximum efficiency of water flow, to absorb, store, and recycle fluid from which nutrition and sustainability are derived. There is wisdom and solution there.
As an example, consider Dagang, a town in the Nansha District, Guangzhou Province, China, a city vulnerable to flood disasters from heavy rainfall, offshore tide level, and the continuing effects of typhoons, the Pacific Ocean version of hurricanes. The city decided to experiment with what was called the “sponge city” concept, an innovative analysis of the ground conditions, soil absorbability, road and construction patterns, and integrated urban design driven by the necessity to manage water both retroactively (to mitigate existing conditions) and proactively to design or re-design adaptation to projection of future conditions. Dagang retained the Danish Hydraulic Institute, an international design enterprise that has developed proprietary software to incorporate numerous layers of physical, social, and financial data for a systems analysis approach to revolutionary planning. I have discussed their work often as I believe it is the most compelling planning tool for adequate, necessary, creative response to the urban problems that beset us. DHI has used the approach for local solutions as well as massive regional studies and recommendations that transcend historical reality, geopolitical boundaries, and inter-related, integrated socio-economic conditions.
The remnants of Ida passed south of where I live, with intense rainfall, no wind, saturated soil, and record erosion and water volumes in the streams and rivers, overland, over the roadways and through the culverts and the storm drains, overwhelming the limited sanitation and treatment facilities and water control systems now under-designed for the climate change defined conditions we face. My town might do well to think of itself as a sponge city, might do well to understand the regional solutions that will be required to absorb these challenges. The old methods will not serve. We need to recognize the flow of water — the freshwater ocean continuum — as the primary organizing principle for successful community. We need to adapt through invention; we need to start thinking like a sponge!
PETER NEILL is founder and director of the World Ocean Observatory, a web-based place of exchange for information and educational services about the health of the world ocean. He is also host of World Ocean Radio, upon which this blog is inspired. World Ocean Radio celebrates 12 years this year, with more than 600 episodes produced to date.