The City of Miami Beach operates a Citywide Stormwater Management System that collects, conveys, and disposes of stormwater runoff from public rights-of-way. The primary function of this system is to facilitate travel along thoroughfares while maintaining a safe and livable condition for the City’s residents and visitors. Recently, the City has undertaken a significant capital program that upgrades the system to account for sea level rise and climate change.

During the development of its capital program, the City consulted numerous subject matter experts (including the Urban Land Institute) and developed a holistic stormwater management strategy -- one that attenuates flooding while mimicking nature’s water cycle. The strategy provides the framework for a sustainable approach to stormwater management. It includes the raising of roadways to minimize sunny day flooding and incorporates green infrastructure that replenishes the freshwater lens and mitigates the transport of excessive nutrient loads onto Biscayne Bay. However, in order to accomplish these and other key goals, the strategy promotes the use of green spaces that allow water to temporarily pond and percolate into the ground.

While this strategy provides numerous benefits, it requires our residents and stakeholders to live with water. This may mean living with minor ponding to promote the replenishment of the freshwater lens.

In an effort to better understand our most flood prone areas, define where flood mitigation would be most effective, and identify areas that are living with water, the Public Works Department uses a data driven approach to measure the efficacy of the stormwater system, analyze flood events, and make improvements.

In 2019, the Chief Resilience Officer and Senior Resilience Analyst worked with the Public Works Department and Environment and Sustainability Department to develop an internal PowerBI Stormwater dashboard, where customer complaints, work orders related to flooding, tide levels, and additional data are entered.  The intent is to provide a holistic view of the event: one that illustrates areas where flooding presented a significant challenge within the City and also identifying where flooding is avoided.

At its May 26, 2020 meeting of the Land Use and Sustainability Committee (LUSC), a Power Point was presented by City staff describing this data. Following the presentation, Commissioner Samuelian expressed an interest in obtaining a flooding scorecard tool utilizing flooding data over time to help with policy decisions related to road raising and drainage due to sea level rise, tidal flooding and rain events.

The envisioned scorecard would provide data and indicators as to the history and extent of flooding in neighborhoods across the City.  The scorecard could include data presented visually through maps that allow users to compare flooding over time and in various areas. Users would have the ability to track flooding year after year and separate areas with stormwater improvements from those that have not yet been improved.

Public Works and the Chief Resilience Officer have discussed the scope with engineering firms to determine a fee for the project.  The consulting firms with expertise in this field that were originally considered are: Avanti, In-Situ, Johnson Controls, CES, and AECOM.   After conducting initial meetings with the firms, it was determined that two firms came closest to meeting the City's needs: AECOM (which were representing Kisters), and CES utilizing the SMARTCOVERS technology.  These two firms have submitted ballpark estimates for the development of a scorecard as well as procuring and installing flood level sensing equipment.  

In an effort to normalize pricing, the quotes obtained from both firms included the same number of sensors.  Both estimates include the installation of a total of 65 flood level sensing equipment throughout the City (five per neighborhood). While these sensors do not cover the entire City, as originally anticipated, it provides a representative analysis of all neighborhoods while minimizing costs.

The equipment includes solar powered cameras and sensors capable of operating remotely through cellular and internet services. Data would be presented through a web-based portal. Both options include a one-time furnishing and installation cost and incur a yearly operating cost. Below is a table showing a summary of both estimates:

Both technologies were purported to provide accurate and reliable water level measurement.

Results from the 2019 Resident Survey show that 50% of residents rated efforts to manage stormwater drainage and flooding as excellent or good. In order to continue maintaining excellent standards in this area, the City intends to continue to use a data driven approach to measure the efficacy of the stormwater system.

Collecting empirical data is essential to an accurate flooding scorecard. The technologies proposed by both consultants would help collect such data. However, in order to provide a truly comprehensive scorecard, more sensors would be needed. This would increment the price substantially. Additionally, significant resources would be required to maintain the sensors and analyze the data - resources that are not currently available.

Perhaps most importantly, the benefits from this scorecard were determined to be limited to refining previous studies. Flooding across the City of Miami Beach has been analyzed and documented, both from a rainfall and an elevation perspective. In order to obtain more precise knowledge, many more sensors would need to be installed throughout the City, at an additional cost.