This month we are highlighting the challenges cities face when it comes to water, too much and too little. In the case of Monroe County, FL this means addressing the current and future challenges brought by sea level rise. Rhonda Haag, the Sustainability Director of Monroe County, shares with us how her community is adapting.
Monroe County, encompassing all of the Florida Keys, is a low-lying chain of islands stretching more than 120 miles from Key Largo to Key West. Many of these islands are barely above sea level and because of the many hundreds of miles of shoreline, the County is considered by many to be ground zero for experiencing the impacts of sea level rise and other aspects of global climate change.
Over the past 100 years, the level of the sea has risen about 9 inches. Even this amount of sea level rise has been felt throughout the Keys. Many upland forests, which depend upon fresh water for their existence, are shrinking along their low-lying edges and becoming dominated by more salt-tolerant plants. Mangroves are taking over from pine trees, gumbo limbos and other upland plants. Key deer and other freshwater-dependent wildlife species, many of which are listed as threatened or endangered, are slowly losing access to the marshes and water holes that supply them with drinking water. There are no local fresh water resources that serve Monroe County’s 75,000 citizens and 2 million annual visitors. The fresh water supply is brought down by pipeline from a wellfield on the mainland in neighboring Miami-Dade County to the north. Predictions of a changing climate include wider climate extremes – dryer droughts and wetter wet seasons – which will complicate the already delicate balance of aquifer recharge and extraction from this and other wellfields.
Not only are the islands’ coastlines experiencing the effects of the rising sea, but the very surface on which the homes and roads are built is composed of porous limestone that allows the waters to rise up slowly in low-lying regions even deep in the interiors of islands. In addition, the 500 canals that exist throughout the County are another opportunity for the rising seas to flow into streets and yards.
Given its unique vulnerabilities to sea level rise, as well as its international exposure as a premier tourist destination, Monroe County has an opportunity to demonstrate leadership on this issue through the implementation of key policies, practices and investments that will prepare the County for the impacts of climate change. As a result, the County is acting now to establish local policies, initiatives and projects to combat the future effects of climate change and make the County more resilient to sea level rise.
In Monroe County’s STAR submission, sea level rise and “nuisance flooding” were identified as two of the core areas of local climate adaptation concern. What are the major vulnerabilities these two areas pose to the County?
With increasing sea level rise, more localized flooding is inevitable in our island community. Currently, this tidal flooding results in seawater inundating street ends and low lying areas. The National Oceanic and Atmospheric Administration establishes certain levels called “nuisance flooding” whereby the mean high water is exceeded by a certain level. In the Keys, this point is slightly higher than a foot above that highest high tide of the day. Our modeling has helped us predict how much nuisance flooding from sea level rise we will see in the future. But some of our predictions in later years (such as 2060) are showing that the sea level rise impacts are of such a frequency that they will no longer be just a “nuisance” and will become a static condition with weekly or even daily flooding. This modeling of our habitat shows us how much landscape will shift due to that saltwater inundation and in particular, our modeling also shows us where our roads are vulnerable. This data collection effort was a centerpiece of our STAR submission because our goal was to create a robust vulnerability analysis so we can plan for the future.
Monroe County recently updated elevation maps that show the effects of local sea level rise, using sea level rise predictions provided from the Southeast Florida Regional Climate Change Compact (“Compact”). The Compact projects a sea level rise of 9 to 24 inches in the next 50 years (predicted on a 2010 baseline). The data shows that even using the conservative estimate, many streets in the County can expect to see significant nuisance flooding on a regular basis.
Monroe County communities have already been experiencing regular flooding from storm water ponding and tidal inundation, a concern that will likely be exacerbated by expected increases in sea level rise. This was highlighted in October 2015, when during the fall King Tide events, up to 16 inches of tidal flooding occurred in the streets of a Key Largo neighborhood and remained for 3 weeks, unable to recede even during periods of low tide.
To help plan for these situations in the future, the County is now moving forward with two roadway demonstration projects, one in the lower Keys and one in the upper Keys. These projects will help determine the type of actions that could be taken to maintain an appropriate level of service along roadways within the two communities. They will include future flood risk from sea level rise and integrate storm water, tidal flooding and road design features to prepare for additional tidal flooding in the future. These innovative projects will also help define alternative levels of service for consideration by the County that account for future tidal risk. Levels of service include whether the County will be able to consistently maintain its roads and avoid flooding adjacent property owners- what we must balance in the future. Once acceptable levels of service are defined, possible strategies for those roadways will include cost estimates.
The project is organized to develop a full understanding of inundation, both currently and longer term – followed by the development of engineering responses and policy recommendations.
When did Monroe County start planning for sea level rise and what were the first steps?
Monroe County has taken a leading role in the regional effort to combat climate change. The County has devoted resources to sustainability planning initiatives since 2007. Other nearby communities in Florida also recognize the risk climate change poses to their citizens, infrastructure, and economies. Monroe County partnered with Miami-Dade, Broward, and Palm Beach Counties in 2010 to develop and sign the Compact. The Compact represents a new form of regional climate coordination designed to allow localities to set the agenda for adaptation while providing an efficient means for state and federal agencies to help with technical assistance and support.
Other milestones in recent years include:
- In 2012, the Monroe County Board of County Commissioners (BOCC) approved a sustainability staff person to address sustainability and climate change. The department launched its new Sustainability website in 2015.
- In 2013, the County developed the Monroe County Community Climate Action Plan which outlines a course of action for the County to minimize climate change impacts and increase the sustainability of communities within the Florida Keys.
- In December 2015, the County hosted the regional 7th Annual Climate Leadership Summit, with the City of Key West, Islamorada and Marathon as co-hosts. This Summit focused on climate-related collaboration, outreach and preparation activities that the 4 Compact Counties and subscribing municipalities are preparing for and implementing. Over 450 guests attended the event.
- In January 2016, the County BOCC hosted a full day public workshop to review the recently completed draft GreenKeys! Sustainability Action Plan that will help the County prepare for the uncertain effects of future sea level rise.
The County is intent on making the entire community more resilient, and in the process protecting the homes, economic vitality and unique quality of life that the island communities offer. Resources are limited however, so as a community, the County will need to make some choices about priorities. The GreenKeys! Sustainability Action Plan will help prioritize projects and the funding for them.
Climate change models predict varying levels of sea level rise, how is Monroe County planning for these different scenarios? How do you prioritize needed investments depending on the different scenarios?
Inundation levels for today will change given projected future sea level rise values identified in the GreenKeys! planning effort. The primary intent of the demonstration projects discussed above is to develop an understanding of how those sea level rise projections will impact inundation in two pilot communities. The specific efforts to be completed under the project include:
1) Utilize sea level rise values for 2030 and 2060 to identify rates of change that can be applied by decade to define the timeframe of future inundation; and
2) Develop inundation levels that reflect those future values and identify how they may impact the inundation in each of the two pilot communities.
The data gathered will be combined to determine an estimate of probability of flooding for the two neighborhoods, as well as the water levels associated with each of those probabilities as a means of providing data by which important policy decisions on levels of service delivery can be made in the future.
Staff will discuss policy issues with County officials to identify appropriate targets for inundation levels based on alternatives to be developed by the Project Team. This discussion would include the identification of various levels of flooding and how often a roadway should be allowed to be inundated, as well as what design features and costs should be considered in alleviating those future conditions. The outcome will be the identification of design options that could reduce or eliminate flooding. All scenarios will be correlated to the October 2015 King Tide event so people have a physical understanding of how alternative scenarios will actually compare.
The County’s response and how decisions may be made will be dependent on how the County prioritizes those improvements for implementation County-wide and any regulatory framework actions that can be taken. This project serves as a pilot effort to begin making similar decisions based on future sea level rise projections.
What infrastructure investments has the County made so far and what will be the biggest infrastructure needs related to sea level rise be in the coming decades?
The GreenKeys! Sustainability Action Plan efforts cost $200,000, which included preliminary inundation modeling to help the County understand the effects of sea level rise on its roads, bridges and facilities. The County is now moving forward with a $450,000 effort to update its elevation data, using mobile LIDAR data to replace the existing less-accurate aerial elevation data on record. This data will assist the County in setting levels of services for its infrastructure. The County can then begin to design its roads and facilities to withstand the impacts of sea level rise.
The total design costs will depend on the level of service the County selects, based on its needs and available resources. The needs are great, and the potential expenditures even greater. The County has more than 300 miles of roads, all ground level. It also has many public facilities located throughout the 100 mile length of the County, many of which may need flood proofing if not already elevated. Preparing its infrastructure to continue to meet the needs of its residents and many visitors will be an ongoing challenge during the coming decades.
How will sea level rise affect the average citizen and how is the county engaging them?
The County’s GreenKeys! Sustainability Action Plan contains strategies and recommendations that are meant to help guide the County and its residents in becoming more sustainable and more resilient over time. The Plan seeks to engage the community and build resilience in the face of challenges, including climate change, sea level rise and even economic crises. More than 15 public meetings were held throughout the Keys during the development of the Plan, where residents were invited to learn about sea level rise and how it could affect their homes and businesses. The County had a very active MindMixer public engagement website where numerous suggestions were made. The Plan was made available for public comment for over 60 days. A full day workshop was held where the public attended. There were numerous other Commission briefings and presentations to homeowners associations, chambers of commerce and other organizations. Detailed modeling was done for select neighborhoods so that residents could see street by street the inundation that could be expected.
The County will continue to host public meetings and conduct other public outreach on a continuous basis so that its residents can remain aware of the coming changes and what the County is doing to prepare.