Environment, Coasts, Oceans, & Infrastructure

ASCE's Source has an article about relative sea level rise issues along much of our coastlines and what engineers ae doing in response. LINK 

What is being done in your region to adapt to relative sea level rise?

Bill Mc

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William McAnally Ph.D., P.E., BC.CE, BC.NE, F.ASCE
ENGINEER
Columbus MS
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Bill – the Source article is a good read – and nice to see diverse opinions on the issue of Global Sea Level Rise (SLR) – and its regional outlay in terms of relative sea level rise (RSLR), in particular on sinking or subsiding coasts.

You and I and other learned colleagues interacted on this and related issues before in this forum. I will add some of my own findings and thoughts based on three essays: Sea level Rise – the Science; Sea level Rise – the Consequences and Adaptation; and Warming Climate and Entropy. In all these pieces, I have quoted National Academies Publications and 2021 IPCC Working Group findings – in particular with respect to their findings and predictions in terms of probability scale.

Perhaps – one can begin by seeing the Earth System – as consisting of three subsystems – the Fluid, the Solid and the Life. And it is helpful to see the issues in terms of Stress, e.g. . . . global warming is the stress with SLR as the consequence – in turn SLR is the stress with the consequences on human livelihood in the coastal zone . . .

Although we know all these, allow me to drift somewhat to the understandings of interactive and interdependent balancing processes. Earth's Fluidity, Solidity and the Life system evolved naturally in the past – until the beginning of industrial age. Beginning at this epoch, anthropogenic factors started accelerating the Earth-Sun energy balance – unbalancing the climate. 

The significance and extent of RSLR – can best be understood from some quoted values. While SLR . . . has accelerated since the late 1960s, with an average rate of 2.3 [1.6 to 3.1] mm per yr over the period 1971–2018 increasing to 3.7 [3.2 to 4.2] mm per yr over the period 2006–2018 . . . the RSLR at the Mississippi River delta, the present SLR rates vary from +9 to +12 mm per year, far higher than the global average.

Apart from what are highlighted and discussed – in my judgment, the most crucial issue is how to address the SLR-RSLR consequential adverse effects on vulnerable coastal civil infrastructure in heavily built and urbanized areas. What mitigation and adaptation mean for these areas – in light, further of enhanced storm and wave activities – and reduction of gravity drainage hydraulic head. 

And generally in terms of coastal erosion, saltwater intrusion and enhanced pore water pressure on coastal aquifers.

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Dr. Dilip K Barua, PhD

Website Links and Profile

Thanks, Dilip. Good insights as always. Your essays are always useful.

Bill

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William McAnally Ph.D., P.E., BC.CE, BC.NE, F.ASCE
ENGINEER
Columbus MS
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Original Message:
Sent: 07-05-2026 08:04 PM
From: Dilip Barua
Subject: Relative Sea Level Rise

Bill – the Source article is a good read – and nice to see diverse opinions on the issue of Global Sea Level Rise (SLR) – and its regional outlay in terms of relative sea level rise (RSLR), in particular on sinking or subsiding coasts.

You and I and other learned colleagues interacted on this and related issues before in this forum. I will add some of my own findings and thoughts based on three essays: Sea level Rise – the Science; Sea level Rise – the Consequences and Adaptation; and Warming Climate and Entropy. In all these pieces, I have quoted National Academies Publications and 2021 IPCC Working Group findings – in particular with respect to their findings and predictions in terms of probability scale.

Perhaps – one can begin by seeing the Earth System – as consisting of three subsystems – the Fluid, the Solid and the Life. And it is helpful to see the issues in terms of Stress, e.g. . . . global warming is the stress with SLR as the consequence – in turn SLR is the stress with the consequences on human livelihood in the coastal zone . . .

Although we know all these, allow me to drift somewhat to the understandings of interactive and interdependent balancing processes. Earth's Fluidity, Solidity and the Life system evolved naturally in the past – until the beginning of industrial age. Beginning at this epoch, anthropogenic factors started accelerating the Earth-Sun energy balance – unbalancing the climate. 

The significance and extent of RSLR – can best be understood from some quoted values. While SLR . . . has accelerated since the late 1960s, with an average rate of 2.3 [1.6 to 3.1] mm per yr over the period 1971–2018 increasing to 3.7 [3.2 to 4.2] mm per yr over the period 2006–2018 . . . the RSLR at the Mississippi River delta, the present SLR rates vary from +9 to +12 mm per year, far higher than the global average.

Apart from what are highlighted and discussed – in my judgment, the most crucial issue is how to address the SLR-RSLR consequential adverse effects on vulnerable coastal civil infrastructure in heavily built and urbanized areas. What mitigation and adaptation mean for these areas – in light, further of enhanced storm and wave activities – and reduction of gravity drainage hydraulic head. 

And generally in terms of coastal erosion, saltwater intrusion and enhanced pore water pressure on coastal aquifers.

--------------------

Dr. Dilip K Barua, PhD

Website Links and Profile

The City of Charleston, South Carolina, has partnered with the Corps of Engineers to address flooding across the city peninsula from sea level rise, storm surge, and stormwater.  The proposed system consists of a raised edge at the peninsula perimeter with an interconnected integrated stormwater management system.  The city has existing low and high batteries along the water's edge which would be extended.  For more information, see Feasibility Study  

The Corps of Engineers also has a Charleston Tidal and Inland Study which will also look at flood risk to the city and areas west and south of the city.

The City of Charleston has initiated flood risk reduction strategies, including a flooding and sea level rise strategy.  Flooding & Sea Level Rise Strategy | Charleston, SC - Official Website  NOAA analysis indicates Charleston experienced high tide flooding events 2 days per year (4 hours total) in 1950, increasing to 25 days per year (42 hours total) by 2014.  High tide flooding events are projected to increase to 60-75 events per year (103 hours total) by 2051. 

Closer to home, the Town of Hilton Head has engaged consultants to develop a sea level rise and climate adaption resiliency plan to assess vulnerabilities and guide policy and infrastructure investments.  For water supply, the public service district has a reverse osmosis drinking water treatment facility which can be expanded to meet future demand including replacement of water lost from saltwater intrusion.   Beach nourishment is a part of the town's current plans every 8 to 10 years and should continue into the future.  The most recent beach nourishment, 2025-2026, consisted of 2.2 million cubic yards of sand places along 46,500 ft of shoreline. 

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Nancy Powell P.E., BC.NE, BC.WRE, M.ASCE
Hilton Head Island SC
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Thanks Nancy – I have downloaded the linked reports. Great to know all these. I remember my two field trip days, as well as the sight seeing visits – during the 1988-91 period while studying at USC.

One of the cited reports links to the 2019 'Flooding and Sea level Rise Strategy' – which is interesting in the context of this discussion – and in light of the Flood Barrier Systems Essay chalked out in my website. On 'Putting Science First' – the measured and projected RSLR are presented – the bases of USACE design study.

Among the 'Five Critical Components' of 'A Strategic Plan' – the Resources, Land Use, Outreach, Infrastructure and Governance – the used RSLR for the existing port and coastal infrastructure protection is worth mentioning here.

Compared to the 2015 project – the present 2019 design RSLR varies from 2-foot for less vulnerable structure to 3-foot for more critical long term infrastructure.

And the identified works in this sphere of activities include – Low Battery Seawall, Forest Acres Drainage, Drainage Projects, Check Valve Program and Drainage Maintenance. Interestingly, no feasibility or infeasibility of Storm Surge Barriers is mentioned.

Perhaps – this subject is covered in some regional studies of the Eastern Seaboard – but, I couldn't find any such study reference.

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Dr. Dilip K Barua, PhD

Website Links and Profile

Original Message:
Sent: 07-18-2026 04:39 PM
From: Nancy Powell
Subject: Relative Sea Level Rise

The City of Charleston, South Carolina, has partnered with the Corps of Engineers to address flooding across the city peninsula from sea level rise, storm surge, and stormwater.  The proposed system consists of a raised edge at the peninsula perimeter with an interconnected integrated stormwater management system.  The city has existing low and high batteries along the water's edge which would be extended.  For more information, see Feasibility Study  

The Corps of Engineers also has a Charleston Tidal and Inland Study which will also look at flood risk to the city and areas west and south of the city.

The City of Charleston has initiated flood risk reduction strategies, including a flooding and sea level rise strategy.  Flooding & Sea Level Rise Strategy | Charleston, SC - Official Website  NOAA analysis indicates Charleston experienced high tide flooding events 2 days per year (4 hours total) in 1950, increasing to 25 days per year (42 hours total) by 2014.  High tide flooding events are projected to increase to 60-75 events per year (103 hours total) by 2051. 

Closer to home, the Town of Hilton Head has engaged consultants to develop a sea level rise and climate adaption resiliency plan to assess vulnerabilities and guide policy and infrastructure investments.  For water supply, the public service district has a reverse osmosis drinking water treatment facility which can be expanded to meet future demand including replacement of water lost from saltwater intrusion.   Beach nourishment is a part of the town's current plans every 8 to 10 years and should continue into the future.  The most recent beach nourishment, 2025-2026, consisted of 2.2 million cubic yards of sand places along 46,500 ft of shoreline. 

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Nancy Powell P.E., BC.NE, BC.WRE, M.ASCE
Hilton Head Island SC
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It's good news that SC cities are making adjustments, Nancy. Thanks for news of those advances. It's going to be expensive, but not as expensive as doing nothing and suffering catastrophic losses. 

Bill

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William McAnally Ph.D., P.E., BC.CE, BC.NE, F.ASCE
ENGINEER
Columbus MS
------------------------------

Original Message:
Sent: 07-18-2026 04:39 PM
From: Nancy Powell
Subject: Relative Sea Level Rise

The City of Charleston, South Carolina, has partnered with the Corps of Engineers to address flooding across the city peninsula from sea level rise, storm surge, and stormwater.  The proposed system consists of a raised edge at the peninsula perimeter with an interconnected integrated stormwater management system.  The city has existing low and high batteries along the water's edge which would be extended.  For more information, see Feasibility Study  

The Corps of Engineers also has a Charleston Tidal and Inland Study which will also look at flood risk to the city and areas west and south of the city.

The City of Charleston has initiated flood risk reduction strategies, including a flooding and sea level rise strategy.  Flooding & Sea Level Rise Strategy | Charleston, SC - Official Website  NOAA analysis indicates Charleston experienced high tide flooding events 2 days per year (4 hours total) in 1950, increasing to 25 days per year (42 hours total) by 2014.  High tide flooding events are projected to increase to 60-75 events per year (103 hours total) by 2051. 

Closer to home, the Town of Hilton Head has engaged consultants to develop a sea level rise and climate adaption resiliency plan to assess vulnerabilities and guide policy and infrastructure investments.  For water supply, the public service district has a reverse osmosis drinking water treatment facility which can be expanded to meet future demand including replacement of water lost from saltwater intrusion.   Beach nourishment is a part of the town's current plans every 8 to 10 years and should continue into the future.  The most recent beach nourishment, 2025-2026, consisted of 2.2 million cubic yards of sand places along 46,500 ft of shoreline. 

------------------------------
Nancy Powell P.E., BC.NE, BC.WRE, M.ASCE
Hilton Head Island SC
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