Miami Beach Stormwater Infrastructure Adaptation
The City of Miami-Beach is taking action to protect Miami Beach roads, sidewalks, storm drains, and other key infrastructure from sea-level rise and flooding by installing pumps, raising roads, and protecting the city with seawalls. The project seeks to guard both critical resources like the City’s water and power supply as well as roads and property from flooding. The City is in the process of investing an estimated $500 million for this project that is slated to last six more years. Funding comes from local taxes and 84% increase in stormwater fees. Miami Beach is also lobbying for additional state and federal support.
Miami Beach, home to about 90,000 permanent residents and many more visitors, is already experiencing tidal flooding that overwhelms its gravity-based drainage system. The City sits on one large barrier island and a number of manmade islets. During high tides, water can infiltrate the limestone underneath the island and overwhelm storm drains, causing water to flood streets, sidewalks, and buildings. Numerous King Tides in the last few years have resulted in widespread flooding that made roads impassable. Sea-level rise is expected to increase the frequency of flood events.
In response, Miami Beach released an updated stormwater management master plan in 2012 that considered how sea-level rise would impact stormwater infrastructure over the next 20 years and how it would impact the city’s sea wall heights over the next 50 years. The plan relied on sea-level rise guidance from the United States Army Corps of Engineers (Engineering Circular 1165-2-212: Sea-Level Change Consideration for Civil Works Programs). The plan prioritized capital improvements aimed at ensuring Miami Beach modernized their existing systems for flood control and water quality. In 2013, under a new commission and mayor, Miami Beach moved even faster to revamp the City’s plumbing system, raise sea walls, and increase the elevation of roads by as much as six feet.
Additionally, in 2013 the City of Miami Beach endorsed a Regional Climate Action Plan, which was produced through the Southeast Florida Regional Climate Change Compact (“Compact”), a collaborative effort between Broward, Miami-Dade, Monroe, and Palm Beach Counties to coordinate mitigation and adaptation activities across county lines. This plan further highlighted the importance of road elevation and investments in water infrastructure, identifying these actions as high priority for the city. The compact also developed a standard set of sea-level rise projections for the region intended for both short and long-term planning purposes. The most recent analysis (October 2015) projects that the region will see 6-10 inches of sea-level rise by 2030 and 14-27 inches by 2060.
The work to elevate roads creates some engineering challenges. Miami Beach must reconcile elevating roads with the elevations of existing development. For example, if elevated roads end up sitting above existing buildings’ entryways, the city must also take action to prevent those properties from flooding. Additionally, Miami Beach must import sands from the Florida mainland, since dredging the nearby Biscayne Bay is prohibited, making the project more costly.
Miami Beach prioritized roadways for improvements based upon areas that previously flooded and a number of these projects are already underway. To expedite implementation, the city used emergency authority to waive the public bid process. The city expanded a design-build contract they had with a contractor to conduct stormwater improvements along 18th and 20th street, including the reconstruction of a water main, the replacement of a pump station, adding more injection wells, and building a gravity storm sewer system. In 2014, this project was expanded by $4 million to allow for more work on elevating roads. In an effort to get the work done quickly, the city also waived the public process in 2014 when contracting for work to improve four pump stations at 6th, 10th, 14th, and 17th Streets, a new sanitary sewer main, a new water main and service line, and upsizing sections of the storm water drainage system. The contract also involves elevating roadways by two feet and constructing new sidewalks, gutters, street lighting, and driveway reconstruction.
This Adaptation Clearinghouse entry was prepared with support from the Federal Highway Administration. This entry was last updated on January 28, 2016.
- City of Miami Beach, Florida
- Best practice
- Case study