In order to address flooding, the City of Miami Beach is investing over $650 Million in various infrastructure improvements, over an estimated span of 10 years. The infrastructure improvements include installing larger pipes, building pump stations, raising roads, and constructing seawalls to ensure that the roads do not flood in future tidal and rainfall events.

Temporary pumps have been deployed to mitigate King Tide events in low areas of the City, such as Upper North Bay Road, Orchard Park, Indian Creek, Tatum Waterway, and other North Beach neighborhoods. However, these measures only attenuate localized street flooding and are unsustainable practices for major storm or tidal events.

At its January 27, 2020 Commission Workshop on Resilience, the Public Works Department offered the Commissioners a presentation on temporary pumps (see attached) that depicts citywide locations where temporary pumps were to be deployed.

Two scenarios were offered to the Commissioners for discussion: a 14 pump deployment (which would allow for some standing water to remain, as recommended by the Urban Land Institute) or a 28 pump deployment (which would provide a higher level of service), to be tested for a period of six months, at a cost of $454,000 and $890,000, respectively.

At its February 18, 2020 meeting, the Land Use and Sustainability Committee (LUSC) held a discussion regarding properties in areas that continuously flood during rain events or King Tides. While there is a resilience program that will identify these needs, many neighborhoods will not be improved until a later date. Committee members inquired whether there was an interim solution for such homes, perhaps with the inclusion of blue/green initiatives. The Public Works Department offered alternatives to be considered for discussion.

At the end of the discussion, the Committee resolved to bring forth a plan that includes a list of locations where blue/green infrastructure solutions may be applied. The plan would also include a high-level cost estimate and funding alternatives for the locations. Upon finalizing the BGSI practices, the Administration was requested to bring  back the plan to the Committee. It was noted that this plan would be in addition to the proposed 14 pump deployment.

At the May 6, 2020 meeting of the LUSC, Public Works presented its members a blue/green infrastructure (bioswale) pilot program for consideration. The target area for this pilot program was to be a residence in the LaGorce Neighborhood, an area known to flood during heavy rain due to its low-lying elevation.

BLUE/GREEN INFRASTRUCTURE

A typical blue/green infrastructure installed within the right-of-way is a manmade swale (bioswale) typically vegetated and/or mulched with engineered soils below the surface.  It can improve water quality by allowing water to collect naturally in the bioswale depressions and drain through the engineered soils beneath the surface rather than passing into storm sewers.  It may be designed to capture the first 1.5 inches of rainfall during storm events.

The City is considering implementing a pilot project as means to test the efficacy and value of this type of technology.

A bioswale can provide the following benefits and limitations:

The request to approve the pilot program was scheduled to be presented at the June 24, 2020 City Commission.  However, following the LUSC motion on May 6, 2020, the owners of the residence selected for the pilot program decided not to proceed.  The residents stated the bioswale would not fully address their flooding issues. 

Public Works staff evaluated a second residence in the North Bay Road neighborhood, also known to flood.  Following discussions with the property owners, they too declined to participate in the City's bioswale pilot program. No other affected property owner has expressed a desire to participate.

On September 11, 2019, the City Commission approved the development of a bioswale pilot project within the West 59th Street right of way, between Alton Road and Biscayne Bay via Resolution No. 2019-30950.  Its design and permitting has been completed.  City staff is currently coordinating its bidding and award process.  The construction of the bioswale is scheduled to start in March 2021 and completed in September 2021.  Once installed, Public Works staff will be testing its efficacy and providing recommendations on whether additional bioswales should be considered for low-lying areas.

Results from the 2019 Resident Survey show that 50% of residents rated efforts to manage stormwater drainage and flooding as excellent/good, and 59% of residents rated stormwater and drainage improvements as excellent/good.  In order to continue maintaining excellent standards in this area, the City continues to consider blue-green initiatives to alleviate flooding.

The Administration recommends proceeding with the bioswale pilot on 59^th Street and evaluating additional locations, on a case by case basis, as residents express interest in participating in a bioswale pilot program.