Desalination and waste water treatment plants can replenish groundwater and slow the sinking of U.S. coastal cities and ports, according to Randy Truby, President, RL Truby & Associates and a former President of the International Desalination Association.
Truby was the keynote speaker at the Storms, Flooding & Sea level Defense 2024 Conference produced by the Propeller Club of Northern California and the Society of American Military Engineers that took place on November 12, 2024.
DEFENDING SINKING CITIES & PORTS
Truby spoke on the topic: “Desalination Strategies to Replenish Water Tables and Reduce Coastal Subsidence”
Truby cited an article published in the science magazine ‘NATURE’ which describes the combined impact of global sea level rise (projected 0.25-0.3 meters by 2050) and the sinking of coastal land areas (coastal subsidence).
The Virginia Tech authors of the report expressed concern that the combination of these forces will accelerate the impact of Sea Level Rise as coastal cities and communities are sinking and as sea levels rise.
The study’s authors argued for more wastewater treatment and ocean desalination to pump water back into water tables so as to slow the impact of subsidence that is sinking U.S. coastal cities and ports:
“The sea level along the US coastlines is projected to rise by 0.25–0.3 m by 2050, increasing the probability of more destructive flooding and inundation in major cities. However, these impacts may be exacerbated by coastal subsidence—the sinking of coastal land areas—a factor that is often underrepresented in coastal-management policies and long-term urban planning. In this study, we combine high-resolution vertical land motion (that is, raising or lowering of land) and elevation datasets with projections of sea-level rise to quantify the potential inundated areas in 32 major US coastal cities. Here we show that, even when considering the current coastal-defence structures, further land area of between 1,006 and 1,389 km2 is threatened by relative sea-level rise by 2050, posing a threat to a population of 55,000–273,000 people and 31,000–171,000 properties. Our analysis shows that not accounting for spatially variable land subsidence within the cities may lead to inaccurate projections of expected exposure. These potential consequences show the scale of the adaptation challenge, which is not appreciated in most US coastal cities.”
That study can be found here: https://www.nature.com/articles/s41586-024-07038-3
Truby noted the threat “may not be appreciated by planners and stakeholders.”
The study focused on 32 coastal cities and ports and found the sinking impact greatest among cities and ports adjoining the Gulf of Mexico.
