The Green Values Stormwater Toolbox aims to help people evaluate sustainable design opportunities. It is based on extensive research into the long-term costs and effectiveness of green infrastructure approaches. Its results are still approximations based on research-based assumptions of green infrastructure performance, soil types, cost ranges, and other key factors.
The calculator was designed based on the hydrology of the Great Lakes region, so the results would be different for other regions with different rainfall patterns. However, the calculator can be used to get a general sense of how green infrastructure might work in other areas.