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Triple Bottom Line (TBL) Assessment Model


The Triple Bottom Line (TBL) approach has been adopted by a number of different groups within the infrastructure planning industry, and a range of methodologies and techniques have been developed. AECOM produced a unique tool (the TBL Assessment Model) that can be used to assess and compare the social, economic and environmental impacts of different development proposals. It is an Excel-based tool that was created for the San Francisco Public Utilities Commission (SFPUC) to assess the impacts of the new $6.8 billion Sewer System Improvement Program (SSIP).


As well as producing a reliable and resilient system, the SSIP aimed to provide a variety of other benefits, such as achieving environmental sustainability while maintaining ratepayer affordability. The TBL Assessment Model was used to compare all these different aspects and to support the development of alternative designs that would better fulfil the original aims.


TBL is a decision-making tool that helps to standardise the way in which diverse projects are assessed. It also allows managers to carry out project evaluations more quickly than using traditional methods. The graphical output is clear and informative, and can be used to report or communicate the range of benefits or impacts effectively, to a range of stakeholders.



Some information on AECOM’s Sustainable Economics page – http://www.aecom.com/What+We+Do/Economics/Practice+Areas/Sustainable+Economics

Project summary for San Francisco’s Stormwater and Sewer Management Program – http://www.dsdic2014.hk/abstract/A4-3.pdf

Vimeo video about the SFPUC case study – https://vimeo.com/58054980