For those who may have eagerly anticipated this I apologize for the delay.
Part 2 of the blog covers some activities in the Gulf an on the East Coast.
The Port of Houston was closed for several days after Hurricane Harvey and both it and Houston itself did not suffer damage from sea rise or storm surge because they are located several miles inland from the Gulf of Mexico. Houston’s flooding was caused by heavy rainfall which resulted in significant “shoaling” (become shallow) with silt being deposited in the Port Channel. The channel and therefor the port was closed for several days while dredges removed it.
Galveston however is right on the Gulf of Mexico. The Houston Chronicle notes a Texas A&M report that if a hurricane like 2017’s Irma hit Galveston head on the property damage could be at least $31 billion just for residential property. Damage to the port and commercial property was not estimated. After Hurricane Ike (2008) hit the area Professor William Merrill suggested that a 17 foot high barrier about 60 miles long from Galveston Island to Bolivar Peninsula <map> similar to projects built in the Netherlands (The Oosterscheldekering Dam would reduce the damage from a storm surge to, about $6 billion – a reduction of more than 80 percent. The estimated cost of $12 billion would pay for itself after one event. There was interest in looking at the feasibility but the financial crisis made any kind of expenditure impossible.
After this past Hurricane season they might have a better chance. State officials asked for the money to be included in post-Harvey Federal disaster assistance. That didn’t happen and it’s not likely that the cost would be included in the overall spending fund Congress has to pass. However it might get into the Infrastructure Program. The Tribune article quotes local U.S. Representative Andy Weber is quoted saying “This is foolish for us to just keep paying for these disasters over and over and over again How about something to prevent this from happening on the next go around?” The Texas General Land Office and the Army Corp of Engineers are doing a joint study which is expected to generate possible construction recommendations by this summer.
According to the World Digital Library more than 450 recorded tropical storms and hurricanes have reached Florida’s shores since European exploration began, more than any other state.
Miami is the fourth largest city on the Atlantic seaboard behind New York, Baltimore and Washington DC (Chesapeake Bay is open to the ocean). Parts of it, particularly Miami Beach, are subject to daytime flooding at high tides About 2,000 homes are constantly at risk from just tidal flooding and 5,000 from a Category 1 hurricane. . Sea level rise and flooding risks will worsen over the next decade.
Although daytime floods often produce only a foot or two of standing saltwater, they are straining life in many areas by killing lawns and trees, blocking neighborhood streets, backing up storm drains, polluting supplies of freshwater and sometimes stranding entire island communities for hours by overtopping the roads that tie them to the mainland.
On December 29th Bloomberg published an article discussing sea rise risk form the Miami area. They linked to a study produced jointly by individuals from University of Colorado and Penn State taking aim the risk discount that the residential market will take on eventual seven percent losses from sea rise. They have focused on the residential market and feel that this analysis will affect the riskier views on commercial markets due to proximity to potential flooding.
As reported in VOA.com “by 2030, we could be seeing it 30 to 40 days a year,” Keren Bolter, climate and policy analyst with the South Florida Regional Planning Council, said. “And by 2060, we could be seeing it almost every single day at high tide. In order for a city to keep track of this creeping disaster 70-plus volunteers are out daily measuring flooded areas to see where there are just saltwater puddles and where streets become streams. They also track potentials for toxic or infectious conditions.
At the other end of the spectrum, Miami’s residents in 2015 approved a $400 million general obligation bond for elevating its roads, re-building its seawall, installing more pump stations, and improving its drainage systems. In addition the city also mandates that new buildings be constructed five feet above current sea levels, and set restrictions on developing in the city’s floodplain. (
NEW YORK CITY
The nation’s largest city is located with two rivers emptying directly into the ocean and one densely populated island. The National Academy of Sciences has a report on Impact of climate change on New York City’s coastal flood hazard. It predicts that the maximum potential for sea rise from now to 2100 is over five feet.
In January 2017 New York because the first major city in the US to publish a preliminary version of Climate Resiliency Guidelines. The New York Port Authority did publish guidelines a few years earlier but theirs is primarily a description of the decision making tree, who does what. The city documents is for “managing uncertainty/”
The guidelines were prepared by the Mayor’s Office of Recovery and Resiliency in conjunction will all departments that are involved in capital projects. Its “primary goal is to incorporate forward-looking climate data into the design of all City of New York capital projects. The Guidelines provide a consistent methodology for engineers, architects and planners to design facilities that are resilient to changing climate conditions.” It is to be used from the initial RFP to the final design. The key issues covered are planning across the useful life and adjustments for increasing heat, increasing precipitation and sea rise projections for which are included for the 2050’s and 2080’s..
New York is the first American city to arrange with FEMA to redraw their Flood Insurance Risk Maps that show where 100 and 500 year floods are likely to occur. As a reminder a 100 year flood zone means there’s a one percent change of a certain intensity flood occurring in a year. Generally mortgage lenders and property insurance companies will require properties within the 100 year flood zone to carry flood insurance. For the most part the insurance is backed by the US government’s National Insurance Risk Program which, as of 2017 is $26 billion in debt.
At the cost of $64 million the city is instating 25 ton doors at the entrances of tunnels between Manhattan and Brooklyn to avoid the flooding that occurred during Hurricane Sandy. They also have temporary barriers for subway tunnel and passenger elevator entrances where flooding occurred that install in 30 minutes as well as fabric covers for selected stairwells. Joseph Lhota, MTA manager was quoted in a Business Insider video “This is not something you go to Home Depot or go to Lowes that you can buy off the shelf. It needed to be made to make sure that it was completely sealed.”
The Army Corps of Engineers is looking at a storm surge prevention project that would protect the Port of New York as well as both Hudson and East Rivers by building a long barrier similar to the proposed Galveston and exiting Rotterdam schemes. The cost is estimated at $25 billion.
Running Google Alerts for “sea rise” and ocean flooding has identified a number of other locations for both coasts, flooding on the East and shoreline deterioration on the West. It also reminds us that other parts of the world are experiencing similar events such as in Paris where the Seine overflowed its banks.
There are many small communities on both Coasts who are addressing their sea rise risks in small ways. The third part of this blog will be a list of those.