Monroe County, Florida Resolution 028-2017 - Interim Road Design Standards

In 2017, as a result of severe tidal flooding from king (i.e. exceptionally high) tides in 2015 and 2016 and increasing sea-level rise estimates, Monroe County, Florida—a low-lying area covering the Florida Keys and Everglades—adopted interim design standards specifying minimum road elevation requirements.1 The design standards are largely informed by recommendations included in the County’s Final Report for the Monroe County Pilot Roads Project: The Sands and Twin Lakes Communities (Final Report) which examined nuisance flooding in Key Largo and Big Pine Key, where king tide flooding was highest. The primary purpose of this elevation standard is to create more resilient roadways and to ensure continued road access in communities facing immediate and growing climate change and sea-level rise challenges. The County formally adopted the recommended interim standard through Resolution 028-2017, approved on January 18, 2017.

The Final Report, which included input from community stakeholders, developed design options for road elevation and stormwater drainage management. The design options, which included 6, 12, 18, and 28 inches of road elevation, were based on 20-year historical trends as well as the Intergovernmental Panel on Climate Change’s (IPCC) high sea-level rise scenarios. It ultimately recommended an interim design standard specifying that road flooding should not exceed 7 days annually over the course of the road’s design life, accounting for anticipated sea-level rise out to 2040. The Final Report also included a draft ordinance building on the St. Johns County “environmentally challenging locations” concept, which would allow disinvesting in roads found to be untenable.

In addition to the Final Report, the County was also influenced in its adoption of new design standards by the GreenKeys! Sustainability Action Plan—a comprehensive 5-year roadmap on how best to approach the worsening issues of sea-level rise and climate change, which the County signed on to earlier in 2017. The GreenKeys! Plan estimated that 144 to 188 miles of County roads could be subject to nuisance flooding by 2030. It also acknowledged that important recent legal cases had arisen around flooding and levels of road service on road, such as Jordan v. St. Johns County.2 

As a result of the Final Report, the Monroe County Board of County Commissioners approved  the start of analysis of all 300 miles of County roads in an effort to identify those that are at the highest risk of tidal flooding. This analysis will include updated Lidar data to provide improved road elevation information since the County’s existing elevation data was collected aerially, which can be up to 6 inches off. The Board also approved budgeting to design raised road elevation of 5 inches for 0.3 miles in Key Largo and 11 inches for 0.34 miles in Big Pine, which is estimated to cost $400,000-$450,000. (Construction, which is not yet budgeted, for these elevations is estimated at $3.55 million.)

Publication Date: January 18, 2017

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