Making a strong business case for green infrastructure

The proposed 10-hectare (25-acre) water garden is located in the Fillmore neighborhood within the broader Gentilly Resilience District in New Orleans. Mirabeau Water Garden aspires to become both an example of sustainable water management for the lowland flood-prone areas of the city, as well as an educational destination for residents who wish to learn about water storage, filtration, and...

This analysis evaluated the financial, social, and environmental benefits of the proposed site design against the baseline “do-nothing” scenario over a 50-year period using a 3-percent discount rate. The lifecycle financial net present value (NPV) for the project from the city’s perspective was found to be US$16.7 million, which is defined as the incremental project costs net of...

Autocase automatically values the TBL impacts of numerous ecosystem services. In the past, some ecosystem services were not valued automatically by Autocase, and so values were generated externally from the model. By incorporating these new analytics to Autocase’s functions, there has arisen new abilities to apply these methodologies to a broader range of projects in need of TBL-CBA.

The low-lying area of Filmore, formerly marshland, is comprised of soils that need water to remain stable. Without it they oxidize, consolidate, and subside. The area where Mirabeau Park will be located has subsided approximately 1.5 meters (5 feet) below sea level over the years. Data taken from NASA’s Jet Propulsion Lab illustrates the yearly subsidence around New Orleans, showing the...

The additional 658 trees and 5,000 shrubs in the garden will provide carbon sequestration benefits. The carbon stored and sequestered is valued by multiplying by the social cost of carbon, which is approximately $43/tonne in 2017. Carbon stored and sequestered provides a benefit of $12,579 in present value terms over the life of the project.

Given that the purpose of the park is for flood reduction, the majority of the benefits are generated by reduced flood risk. Nevertheless, significant value is provided by other eco-system services throughout the project’s life. By including these ecosystem services in the analysis – and valuing these co-benefits in dollar terms – the business case can be made for GI in...

Eric Bill is vice president of economics at Autocase, based in New York. The article is based on the conference paper "National Green Infrastructure Challenge – 100 Resilient Cities Rockefeller Foundation – New Orleans Mirabeau Water Gardens Triple Bottom Line Cost Benefit Analysis,” presented in May 2019 during the...