Building Texas coastal defenses could top $26 billion

Decades from now and at a cost of more than $26 billion, the Texas Gulf Coast from Beaumont to Brownsville could lie behind a protective chain of natural and man-made structures designed to reduce the impact of rising sea levels and potent tropical storms on one of the nation’s most important economic engines.

The region included in the study includes nearly one-quarter of the state’s population including metropolitan Houston and is home to nearly one-third of the country’s oil refining capacity. Texas gulf ports handle more than 15% of the nation’s cargo and the Houston Ship Channel is a vital link in the global movement of crude oil.

As a result of global warming, relative sea level change are increasing the vulnerability of existing coastal defense systems. Damage from hurricanes and tropical storms could become more severe as wind speed is projected to increase with higher sea levels and rising ocean temperatures.

(Read “What works: Marshland restoration.”)

The Coastal Texas Protection and Restoration Feasibility Study was launched by the U.S. Army Corps of Engineers in 2014 to evaluate large-scale coastal storm risk management and ecosystem restoration actions.

The storm surge structure at Galveston Bay would have an 800-foot opening for ship traffic that could be closed during a storm. Source: Texas A&M Foundation

If authorized and funded by Congress, later project phases would include pre-construction engineering and design, construction and operations and maintenance stretching to the middle of the century and beyond.

The report notes that the Texas coast is vulnerable to tropical storms and hurricanes whose impacts are devastating to coastal communities. Among a wide array of risks, the study identified three primary risks as drivers for investment in costal storm risk management and ecosystem restoration on the Texas coast: hurricane storm surge, coastal erosion and relative sea level change.

Those risks are not unique to Texas.

Nationwide, sea-level rise and flooding threaten around $1 trillion in national wealth held in coastal real estate. Florida could lose more than $300 billion in property value by 2100, according to a study by the state legislature that was released in July.

In April, researchers from the U.S. Geological Survey, the University of Illinois at Chicago and the University of Hawaii, wrote that sea-level rise will “radically redefine” coastlines through this century.

Sunny day flooding at high tide is becoming more common in Miami as sea levels rise. Starting next July, contractors building publicly financed projects within Florida’s coastal building zone must complete a sea level impact projection study.

They said that for many coastal regions, projections of global sea-level rise by the year 2100 (anywhere from 0.5–2 meters) are in line with what currently are considered to be extreme but short-lived water level rises due to storms. The researchers said that their findings “underscore the need for immediate planning and adaptation to mitigate the societal impacts of future flooding.”

Coastal regions are not the only areas where Americans may face a greater flood risk. Although the Federal Emergency Management Agency classifies 8.7 million properties as having a substantial risk of flooding, a new approach by a group called the First Street Foundation identifies nearly 14.6 million properties with the same level of flood risk. That means nearly 6 million households and property owners have previously underestimated or been unaware of their current risk. The Foundation’s model suggests the number of properties with substantial risk grows to 16.2 million by 2050.

Coastal damage near Galveston in the aftermath of Hurricane Ike. The proposed coastal defenses could reduce such losses by an estimated $2.8 billion a year.

The recommended Texas coastal plan includes a combination of ecosystem restoration and and coastal storm risk management features that are intended to work together to reduce the risk of coastal storm damages to natural and
man-made infrastructure and to restore degraded coastal ecosystems.

The plan is divided into three groupings:
• A Coastwide ecosystem restoration plan to restore degraded ecosystems that
buffer communities and industry on the Texas coast from erosion, subsidence
and storm losses. This includes a combination of projects at eight locations along the coast, and proposes 114 miles of breakwaters, 15 miles of bird rookery islands, 2,000 acres of marsh, 12 miles of oyster reef and almost 20 miles of beach and dune.
• On the lower Texas coast, a beach restoration measure on South Padre Island is proposed to include 2.9 miles of beach nourishment and sediment
management. The plan proposes beach nourishment on a 10-year cycle.
• On the upper Texas coast, the Galveston Bay Storm Surge Barrier System is
proposed as a system with multiple-lines-of-defense to reduce damage to
communities, critical petrochemical and refinery complexes, Federal navigation channels, and other existing infrastructure in and around Galveston Bay from storm surge.

The proposed upper Texas coast defenses separate Galveston Bay from the Gulf of Mexico to reduce storm surge volumes entering the Bay. Components include:
• The Bolivar Roads Gate System across the entrance to the Houston Ship
Channel between Bolivar Peninsula and Galveston Island ;
• More than 40 miles of beach and dune segments on Bolivar Peninsula and West Galveston Island that work with the Bolivar Roads Gate System to form a continuous line of defense against Gulf of Mexico surge; and
• Improvements to an existing 10-mile-long Seawall on Galveston Island.

Galveston Bay defenses are designed to enable the system to manage risks that are the result of any additional Gulf surge that overtops the Gulf line of defense. The Bay defenses also would provide resiliency against variations in storm track and intensity and relative sea level change. Bay defense components include:
• An 18-mile Galveston Ring Barrier System that would impede bay waters
from flooding neighborhoods, businesses and critical health facilities within
the City of Galveston;
• Two surge gates on the west perimeter of Galveston Bay to reduce surge volumes that push into neighborhoods around the critical industrial facilities that line Galveston Bay; and
• Home elevations or flood-proofing, to further reduce Bay-surge risks along the western edge of Galveston Bay.

The study has an estimated construction cost of $26.13 billion. It said that if damages from storms were distributed equally across the 50-year period of analysis, the planned measures could reduce average annual damages by $2.28 billion a year.

An artist’s concept of a flood barrier that could be closed to protect Galveston Bay and key energy infrastructure near Houston from floods and storm surge.

Author: David Wagman

I live in Colorado where I write about a wide range of topics, and get outside regularly to hike, bike, garden and walk the dog!