By Mike S Payton, Contributing Reporter
MIAMI BEACH, FLORIDA – The City of Miami Beach released the ‘Business Case Analysis of the Stormwater Program: Mid-Point Update’ on September 24th and reported positive results. The business case examines the economic costs and benefits of the investment decision the city, and its residents are making.
Jimmy L. Morales, City Manager, wrote in a letter to the commission, “I am pleased to share that we are halfway through the business case analysis of the stormwater program. […] While routine updates have been provided at the Sustainability and Resiliency Committee, preliminary results of initial modeling tasks are in.”
Miami Beach is investing hundreds of millions of dollars in infrastructure improvements to reduce flood risk, and assessing the stormwater program, including drainage systems, pump stations, and road elevation.
Through a business case they aim to assess the ability of targeted investments to reduce direct impacts from flooding, as well as impacts of recurrent flooding on property values and insurance rates.
To help in the effort, the city has been working with a national climate adaptation planning consultant, ICF, to gather data, create models, and combine information to understand the economic impact of reducing flood risk.
The business case employs three types of modeling; Risk models which are used by insurance companies, Stormwater and drainage models used by engineers, and Economic models are used to understand relationship between certain variables and property values.
Halfway through the business case analysis the modeling tasks are now complete, and the city has preliminary results to share.
In the letter to the commission, the report is that in terms of risk, without investments, storm surge losses increase. Also there was confirmation that public infrastructure investments reduce flooding levels.
The economic model using actual home sales data over a fifteen-year period found that home prices have increased by 8.6 percent to 11.5 percent for each one-foot increase in average parcel elevation.
Also home prices are higher for parcels with more elevated surrounding roads. In the model, home prices increased by 4.9 percent to 14.1 percent for each one-foot increase in nearby road elevation.
The letter to the committee also provided a case study, with the economic model applied to the Sunset Harbour neighborhood in South Beach, analyzing the area before the road raising project (pre-2017) to after the project’s completion (post-2017).
The conclusion was that the value of condominium units within 0.1 miles of Sunset Harbour increased in total value by approximately $41 million or 12 percent. The neighborhood has also avoided potential damage from tidal flooding due to road elevation. Since 2017, the tide levels would have resulted in flooding 44 times.
In July the Miami New Times reported that the Department of Environmental Resources Management (DERM) is concerned about Miami Beach’s stormwater pumps. Following an April 25th meeting, DERM directed the city to “submit a design for a system that can meet County and State water quality criteria.”
When asked if there were there any surprises at this point, Deputy Resilience Officer, Amy Knowles offered by email, “This is a robust analysis based on data and modeling, (the models are outlined in the LTC).”
Also adding, “This is a mid-point update of preliminary results. The city is pleased to have preliminary data about the economic value of stormwater improvements. This will be another way to communicate the value of the public infrastructure improvements to reduce risk. We are looking forward to sharing the final results with the community.”
Among the study’s next steps will be to identify individual adaptation actions a homeowner can take to protect their property and the individual benefits the homeowner may see.
Another step will be to examine the benefits and costs of public investments to the stormwater system across an illustrative neighborhood in the southern part of the city.
Finally, the study will provide a city-wide view of the benefits and costs of stormwater investments. The full report will be complete in early 2020.