The Threat of Flooding in Coastal Communities Rises as Sea Level Rise Lifts Water Tables

When Tropical Storm Eta soaked South Florida with torrential rains in November, many property owners far inland were shocked to see streets and homes flood in their neighborhoods. Experts say that the extreme flooding was due to the enormous amount of rain that fell on land already saturated by heavy rains that fell in October. They also said that the nearly 75-year-old canal system built to drain what had for been Everglades swamplands was unable to cope with the volume of water.

Sea level rise was part of the problem, too. The drainage canals rely on gravity to transport water from land to sea. As sea levels rise, the difference in height between water on and under the land and the ocean is becoming narrower. As a result, floodwaters don’t flow as quickly downslope to the sea, and, during extremely high tides, sea water actually tries to rush inland through the canals.

Another reality of the canal system is that if the region is experiencing higher than normal “king tides” during a storm, authorities who oversee the drainage system have to close gates to keep seawater from rushing up the canals. During heavy downpours, floodwaters can get caught behind the gates and, with no place to go, they accumulate and flood the land.

Sea level rise poses another less obvious threat that’s right under our feet. As the sea rises, water pressure causes it to migrate inland underground through porous rock and/or soil. The pressure from the salt water, which is heavier than fresh water, forces the fresh water upward, effectively raising the water table.

This can have several negative effects. When the water table rises, it saturates the land. When it rains, the water that falls cannot be absorbed by the soil and flooding results. Another negative effect is that the groundwater itself can rise up to the surface and create flooding.

An even nastier effect of rising water tables is that floodwaters can, as was experienced in South Florida, flow into the wastewater treatment system through manhole covers and broken pipes greatly increasing the flow to wastewater treatment facilities. This influx of water can cause the facilities to lose efficiency or fail all-together. The higher water tables can also cause on-site septic systems to fail. Both problems can result in the release of stinky, and potentially infectious sewage into floodwaters and onto the land.

The flooding Eta brought to South Florida isn’t unique to the region, and it illustrates a problem that many coastal communities and real estate owners are coping with now or will confront soon as seas continue to rise.

Many coastal communities from Florida to Oahu are racing to cope with the problem of sea level rise-induced rises in water tables. A superb article by Grace Mitchell Tada titled “The Rising Tide Underfoot” recently published in Hakai Magazine discusses in detail how rising seas are threatening Oahu, Hawaii. As Dolan Eversole, a management coordinator with the University of Hawaii Sea Grant College Program, told the reporter: “Sea level rise does not look like the ocean coming at us. It looks like the groundwater coming up.”

In South Florida, seawater is migrating inland through porous limestone. In Oahu, it moves through basalt rock. The end result is the same. According to the article, higher water tables are wreaking havoc, flooding residential neighborhoods and commercial and industrial areas. It’s also threatening critical infrastructure, such as roads, pipes that carry fresh water, wastewater, and gas, and underground wires that carry electricity and information.

As the groundwater rises, it also has the potential to release and spread toxic substances, such as oil and chemicals, deposited in the soil, which could lead to environmental catastrophe.

As sea levels continue to rise, groundwater issues will pose an even greater threat to at-risk communities.

Owners and buyers of residential and commercial real estate in coastal areas can’t ignore the threat posed by sea level rise-heightened water tables. The flooding can not only damage their property, it can make driving and communicating difficult, it can cause a spike in maintenance costs and in tax and insurance rates, it can discourage buyers from entering the market, which will drive down prices, it can discourage tourism and other business activity, and it could ultimately lead to lenders and insurers pulling out of the local market altogether, which would be the death knell for a healthy real estate economy.

Unfortunately, there is no easy way to combat rising water tables. For example, if you construct sea walls or natural berms, the seawater can easily migrate under and behind them through the porous rock and soil. With this in mind, owners and buyers of real estate in areas at-risk of rising water tables, need to perform due diligence and determine the level of the threat — has it happened in the past, is it happening in the present, and/or how far in the future will it happen. This information is critical when you decide if you can handle the risk and whether it’s worth taking on to begin with.

Tropical Storm Eta Gives South Florida Homeowners a Wake Up Call: Climate Change and Sea Level Rise Flooding are for Real

Tropical Storm Eta made landfall in the mid-Florida Keys, but it left a lasting impression on homeowners 90 miles to the north in South Florida. Many who owned real estate inland away from the coastline in what they thought were high and dry neighborhoods in Palm Beach County, Broward County, and Miami-Dade County woke up on Monday, November 9, to flooded homes, streets and businesses. Climate experts are already saying the devastation is a result of a dangerous confluence of soils already saturated by repeated rain events in October, a tropical storm with heavy rains super-charged by climate change, and a drainage system based on gravity that’s operating less efficiently due to sea level rise.

Bryan Norcross, a hurricane specialist at Local 10 in Miami, said the region has experienced this type of flooding before, just not in recent years. “I’ve been dealing with hurricanes since the 1980s and that’s evolved into discussing how climate and hurricanes fit together,” he said in an article posted on the station’s website. “The fact that sea level is rising and rising a little more than just a half an inch, an inch at a time, that makes our drainage system work more poorly.” In other words, when there’s less difference between the elevation of water pooling on land and water in the drainage canal system and ocean level, the harder it is for the system to move water off the land and into the ocean.

In an opinion piece titled “Historic Eta flooding in Florida areas thought to be drier proves we’re all vulnerable,” Miami Herald columnist Fabiola Santiago described what it was like living in a neighborhood that flooded. She said the experience at her home in Miami Lakes, an inland community she thought was not vulnerable to flooding, was like living on an island. Even if a resident’s house and street weren’t flooded, they were still impacted by the flooding because they couldn’t travel far before they encountered a flooded street.

“If your street didn’t flood,” she wrote, “you still couldn’t get out of your neighborhood because other thoroughfares did flood. Streets were dangerously deeper than they seemed at first.” She also worried that she would lose power and/or internet service due to the flooding.

Santiago’s final paragraphs are a cautionary tale for all who are considering purchasing real estate in coastal areas vulnerable to or now experiencing sea level rise flooding: “Global warming is real folks, not just a concept put out there that only concerns the scientists. Eta’s rains are here to show us just how up close and personal climate change can get in all of South Florida.”

Touring storm damage in my own city in southern Palm Beach County, I saw many streets that normally experience sea level rise flooding, especially in the fall “king tide” months, flooded to a higher level than I’d ever witnessed. Streets that residents needed to travel to get from their homes were bisected by floodwaters rendering them useless. This is a major frustration to many property owners in my area. Experts say property values in areas that experience sea level rise flooding are already appreciating at a slower rate than properties that don’t.

Tropical Storm Eta’s nasty surprise is a reminder to all property owners and buyers that they need to perform due diligence and know the risk of flooding to homes and businesses so they can make an informed decision regarding real estate ownership. It’s also a reminder that they can’t just focus on a given property or neighborhood, flooding in the wider community and region can also impact their ability to get around town and the costs of maintenance, insurance, and taxes, as communities are forced to invest ever more in efforts to prevent flooding events.

Video: A Failed Sea Wall, Sea Level Rise Flooding & You

Coastal cities and towns are taking different approaches to sea level rise flooding. Some communities are ignoring the problem and hoping it will just go away, which is irresponsible considering that the burning of fossil fuels continues to warm the Earth, ice sheets in Greenland and Antarctica continue to melt, the ocean continues to expand, and sea levels continue to rise at an accelerating pace. Some communities are acknowledging the problem but are waiting for it to hit a critical point before they respond — which might be too late. And still others are taking the responsible approach and planning and implementing projects to fend off the floodwaters, but even this approach, as you’ll see in the video, is not risk free.

To protect their property and jobs, buyers, sellers, owners and real estate agents need to know how their community of interest is tackling the challenges posed by sea level rise flooding. And, as this video about a well-intentioned but failed sea wall project in my South Florida community attests, if local government officials are up to the job.

My city clearly illustrates the available options and consequences of which approach a coastal community takes to dealing with sea level rise flooding. Within a half-mile stretch along the Intracoastal Waterway near our downtown core, we have: 1. A section of sea wall currently being raised to protect a roadway, critical infrastructure and million dollar townhouses; 2. A section without a raised sea wall that chronically floods for the four or five month king tide period between September and January with devastating consequences for several property owners; and 3. A section of sea wall that was raised a few years ago that has structural faults that are allowing floodwaters to inundate a park.

As you can see, the city’s approach to managing sea level rise-driven flooding runs the gamut of what’s possible in all coastal communities: Try to protect the property, let it flood, or make an attempt to stop the flooding that, unfortunately, fails. All have lessons for buyers, sellers, owners and real estate agents.

If the improved section of sea wall manages to hold back the floodwaters, then the the city may have found a viable solution — at least on a short-term basis. Sea level rise isn’t ending any time soon. (It’s also important to note here that South Florida is built on porous limestone which can allow sea water to flow under sea walls rendering them ineffective.) The section that’s being allowed to flood shows what can happen if a city doesn’t take on the sea level rise challenge, but the waters, as waters do, continue to rise. And the section with the failed sea wall shows the very real and expensive consequences of a well-intended approach that failed.

The failed section of seawall is falling short for two easily visible reasons: 1. Engineers left a yard-wide gap in the seawall so the cruise boats could easily be serviced — which, even with protective measures installed after the fact, allows floodwaters to course through into the park; and 2. Floodwater bubbles up in joints on the park side of the sea wall, indicating some kind of structural failure. Bottom Line: A failed sea wall is as good as no sea wall at all. Property behind it will still be inundated.

With seas continuing to rise, and mere inches of it posing a threat to property, structures, roads and critical infrastructure, it’s clear that buyers, sellers, owners and real estate agents can’t afford to ignore the problem. They need to know: 1. How their community of interest intends to take on the sea level rise challenge; 2. How the plan, if any, will impact their property; 3. Whether or not the plan makes sense; and 4. If local officials are up to implementing the plan and taking corrective measures if it fails.

Without this level of knowledge, buyers, sellers and owners could be floored when floodwaters show up on their street or at their doors and they’re hit with higher maintenance costs, higher insurance premiums, higher taxes and, if applicable, association fees. They could also have to park a block from their home, take off their shoes and socks, and wade through the floodwaters to reach their doors.

Video: King Tide Season: The Sea Level Rise Stress-Test

King tide season returned to coastal communities this week, and with it came the king tide/sea level rise flooding that periodically inundates roads, real estate and whole neighborhoods. This video, produced for SeaLevelRiseRealEstate.com, features a discussion of the many ways the king tide months — roughly from September-January — provide the perfect stress-test to give real estate buyers, sellers, owners and agents a sense of how well their communities are battling against sea level rise flooding. It also gives them a read on the level of risk sea level rise flooding poses to their property of interest.

As ice sheets in Greenland and Antarctica continue to melt and the ocean heats and expands due to global warming, sea levels are gradually rising. Add the many inches of sea level rise accumulated over the last hundred years or so to the ancient king tides — higher than normal tides due to the unique alignment of the sun and moon in the fall — and you have a recipe for disaster.

Coastal communities all over the world face a greater threat of flooding during this period In the U.S. this can lead to an enormous amount of property damage as well as damage to roads, water pipes, sewer pipes and other critical infrastructure. The end result is that property owners in affected areas can face higher carrying costs, including expensive repairs, insurance premiums, and taxes as communities implement plans to stave off the flood waters.

During the king tide period, buyers, sellers, owners and real estate agents need to take the time to see what’s actually happening in their communities, find out how much worse it could get, study what their local government intends to do to mitigate the flooding, and reach a dry-eyed understanding of how this will impact their carrying costs and property value. This information will help them to make informed decisions regarding real estate transaction.

Properties Miles Inland Can Still Be Subject to Sea Level Rise-Driven Flooding

When we think of properties at risk of sea level rise flooding, we usually picture properties near beaches. Due to Florida’s unique coastal geology, some areas of the state bust that myth. They’re home to real estate that experiences sea level rise-related flooding miles inland.

How is this possible? Many communities on the Florida peninsula are built on porous limestone instead of granite bedrock. As the seas rise, the salt water is able to migrate inland through the limestone. When it meets fresh groundwater trying to flow to the sea, water pressure pushes the fresh groundwater up. As a result, when it rains, the land is too saturated to absorb the runoff, so it pools (floods) on the lowest land.

Miami-Dade County’s sea level rise task force noted in a 2016 report that this dynamic will make it more difficult for the existing network of drainage canals to protect inland properties from flooding.

Government officials in some locations are struggling with the problem. In some cases they’re able to improve the drainage system. In others, they’re not.

A solution they’re increasingly turning to is using federal funds to buyout properties that flood repeatedly. After the properties are purchased, they’ll turn the land into parks and fields that can store excess runoff. This approach, they say, is less expensive than repeatedly repairing properties that flood.

Miami-Dade County and Brevard County together are in the process of purchasing about two dozen inland properties that experience chronic flooding. Overall, Florida state officials have earmarked more than $44 million for buyouts across the state. As sea level continues to rise, this is likely just the beginning of the buyouts.

Not all homeowners are pleased with the buyout program. WLRN, a local public radio station that serves South Florida, canvassed at-risk inland neighborhoods and found homeowners had several concerns. In an article posted on the station’s website, the owners said they didn’t want their property values to decline because buyers were worried about the threat of flooding. They also said they worried that empty lots left after the houses were razed would give the wrong impression that every nearby property was at risk of flooding and further erode the value of their homes.

The hidden threat of sea level rise-driven flooding miles inland from the coast is a powerful reminder to real estate buyers to perform due diligence before submitting an offer on a property. They need to determine whether a property or neighborhood currently floods or if it will flood any time soon. The answer will impact the carrying costs, value and live-ability of the property that caught their eye.

Challenges Facing Southeast Florida — Ground Zero for Sea Level Rise Flooding — Described in Exhaustive BBC Report

With its low elevation and proximity to lots of water on all sides and underfoot, Southeast Florida is clearly ground zero for sea level rise flooding. The BBC recently published an exhaustive report on the current status of sea level rise in the region — that includes the Florida Keys all the way north through Miami, Fort Lauderdale and West Palm Beach — and the challenges of controlling the inundation. The report makes fascinating required reading for anyone investing in residential and commercial real estate in coastal areas that are threatened by surging tides.

The BBC report, written by Amanda Ruggeri, is full of fascinating facts about sea level rise. Among them:

  1. Current predictions are that sea level could rise by up to 10 inches in the region by 2030 and 5 feet by 2100.
  2. Each additional inch of sea level rise can have a substantial affect on coastal real estate.
  3. The region has more people at risk from sea level rise than any other state, and Miami, specifically, has more financial assets at risk than any other major coastal city in the world.
  4. Cities in the region are already making changes to infrastructure to address sea level rise flooding, including raising roads and seawalls and installing hundreds of tidal valves and pump stations.
  5. Despite the efforts to hold back the sea, experts recognize that they will not be able to save every property and neighborhood from flooding.
  6. Every community faces different challenges. Governments, homeowners, business owners, taxpayers, insurers, developers, engineers and planners are going to have to work together to decide how to address sea level rise in their communities.
  7. Each community is an intricate puzzle where making a change to one piece of infrastructure, such as raising a segment of seawall or roadway, can lead to the unintended flooding of neighboring properties.
  8. Reaching consensus can lead to clashes over proposed solutions, costs, potential impacts and private property rights.
  9. Among the encouraging signs is that in the absence of federal and state leadership, county and local governments are forming regional partnerships to address sea level rise in a coordinated fashion.
  10. Among the discouraging signs is that finding funding sources for the hundreds of millions of dollars worth of projects needed to hold back the rising tides is difficult.

While the BBC report provides a broad, holistic view of how Southeast Florida is tackling sea level rise flooding, real estate buyers, owners and agents still need to invest time and effort evaluating how rising tides are impacting their properties and communities before making decisions. Sea level rise is already resulting in increased property maintenance costs, taxes, insurance and association fees in some areas. It’s also hurting the rate of property value appreciation and forcing extreme measures, such as road abandonment and property buy-outs.

As the polar ice caps continue to melt and the oceans expand due to global warming, these sea level rise is going to challenge more and more coastal residents.

Are Dredging and Beach Replenishment Effective Ways to Protect Real Estate Against Sea Level Rise?

In this video, a massive dredger scours sand and mud from the seafloor off Delray Beach, Florida, and pumps it onto the land where it’s used to replenish the eroded beach. The $8 million project is intended to rebuild the beach for tourism and to protect millions of dollars in real estate.

Every year, cities along the Atlantic, Pacific and Gulf of Mexico coastlines spend millions of dollars on beach nourishment projects. In my hometown, Delray Beach, Florida, a massive offshore dredger just started pumping slurry — sand and water — onto the seriously eroded beach to replenish it. The $8 million project is expected to last weeks. (You can see how it works by watching the video I created of the project.)

This type of dredging to replenish a beach has benefits and costs. In our case, the cost of beach replenishment is easily offset by the tourist dollars it attracts to the community. Without a beach, it’s unlikely people would come here and spend money to stay in hotels and dine and shop in the bustling downtown district. The beach also lures real estate buyers into purchasing single family homes, townhouses and condos.

Beyond the economic advantages, the replenished beach also acts as a barrier that protects valuable real estate from storm surges and erosion.

Despite the many positives, beach replenishment has some downsides. It can be harmful to marine animals and shore birds. If the causes of erosion aren’t (or can’t) be addressed, it will have to be repeated on a regular basis. And it can be expensive; and the costs are growing, especially in areas where sand is not in abundance and it has to be trucked in.

Sea level rise is sure to exacerbate the challenges faced by towns that rely on sand replenishment to maintain their beaches. Every inch of sea level rise increases the force of tides and wave action on beaches. The higher and more powerful storm surges that come with climate change and sea level rise will also be problematic.

For now, most cities and towns that rely on beach replenishment appear committed to the practice to protect their tourism trade and valuable real estate. Whether they will be able to foot the bill when the seas get higher and their beaches require more frequent nourishment projects is an X factor that all real estate buyers and owners in coastal areas prone to erosion need to consider.

FEMA’s Updated Flood Maps Will Impact Flood Insurance Premiums in South Florida

The Federal Emergency Management Agency (FEMA), which administers the National Flood Insurance Program, has been touring South Florida to inform real estate owners about how proposed flood maps based on the latest data will impact their flood insurance premiums.

Owners whose property is included in flood zones will pay higher premiums under the new maps that will take effect in 18 months to two years. Experts recommend that they purchase flood insurance now, before insurance premiums spike under the new designation. If they act now, they will not have to pay the substantially higher rates new policy buyers will have to pay as their existing policies will be grandfathered in when the zones change.

The new maps aren’t all bad news. With the new data removing some properties from flood zones, some lucky owners may actually see a reduction in flood insurance premiums.

People involved in real estate in coastal areas need to keep in mind that FEMA maps don’t consider future sea level rise or king tide flooding. Buyers especially need to perform due diligence to find out if a property experiences sea level rise flooding or may experience flooding in the period they expect to own it. Not knowing a property’s flooding status could result in a loss of property value and higher carrying costs, including maintenance, flood insurance, taxes and condo and homeowners association fees.

Local governments have officials who can help property owners who missed the FEMA meetings to decide what to do next.

Real Estate Buyers Need to Be Aware of Sea Level Rise’s Impact on Infrastructure

Buyers of real estate in coastal areas don’t just need to know if the property of interest experiences sea level rise flooding. They also need to know how salty floodwaters are impacting critical infrastructure.

Case in point: Fort Lauderdale, Florida. For decades, officials there have raided the city’s sewer and water budget to fund other projects. Without critical maintenance, the system is collapsing. Last month alone, breaks in a pipe caused 126 million gallons of sewage to course down a neighborhood street and into a river.

In 2017, an engineering firm gave the city an 800 page report that said $1.4 billion worth of work that needed to be completed on the leaky wastewater treatment system to stop the sewage spills. Experts said part of the problem is that the system has aged beyond its useful life. Another problem is that sea level rise is immersing metal pipes in salty water which is causing them to corrode and fail.

Fort Lauderdale isn’t alone in confronting this costly challenge. Miami, too, has a failing wastewater treatment system that has led to spills and huge fines. Many other cities all along the Atlantic, Pacific and Gulf coastlines are bound to get hit with similar problems as their infrastructure is invaded by rising seas.

One thing Fort Lauderdale and Miami have in common is the struggle to find money to make the needed repairs. The only options are higher taxes or bond issues. Either way, property owners are bound to get soaked.

The timing of these costs couldn’t be worse. In addition to the need to upgrade their wastewater treatment systems, both cities need to spend hundreds of millions of dollars to raise roads and pipes and build barriers and pumps to hold back the ocean.

In the end, buyers need to take future tax hikes into account when they’re considering whether or not to purchase real estate in areas impacted by sea level rise flooding. This issue is discussed in detail in “7 sea Level Rise Real Estate Questions.”

Influential South Florida Newspaper Calls for Federal and State Leadership on Sea Level Rise

As South Florida and the Keys recover from a difficult season of king tide sea/ level rise flooding, the Sun Sentinel published an editorial earlier this month that listed the many challenges the region is already facing from flooding and the many ways federal and state leaders are failing to adequately address the problem.

Among the concerns are neighborhoods that were flooded for months during the fall because higher seas gave the floodwaters nowhere to drain, commercial flood insurance premiums jumping 18 percent a year in parts of the Keys that may put them completely out of business in five years, and threats to corals, birds and fish due to warmer ocean temperatures and acidification in a region that depends on the natural world for tourism.

The newspaper’s editors commended the Southeast Florida Regional Climate Change Compact, which is comprised of South Florida and Keys county governments and governing bodies overseeing over 100 cities and two Native American tribes in the region, for demanding action now to take on the challenges posed by sea level rise flooding. They also commended Gov. Ron DeSantis for sending his chief resilience officer, Julia Nesheiwat, to the 11th annual climate summit held this fall in Key West, even if he had to cancel his appearance at the last minute due to “extenuating circumstances.” But they’re critical of Florida Senators Rick Scott and Marco Rubio for making zero effort to attend or send representatives to help them address the problems. (Maybe they’ll overcome their climate change denialism when more of South Florida real estate is inundated.)

What’s clear from the editorial and out every-day experience in the region is that South Florida and the Keys need strong federal and state leadership and financial assistance to address sea level rise flooding NOW. Ignoring the threat rising flood waters pose to our way of life won’t make them go away. We’re at the front line of the battle against sea level rise, but other coastal communities in the U.S. are starting to wake up to the same siren.