− | Below are capital and life cycle cost estimates for the three [[bioretention]] configurations over 25- and 50-year time periods. The estimates of maintenance and rehabilitation (life cycle) costs represent net present values. Operation and maintenance costs are predicted to represent between 25 and 30% of total life cycle costs over the 25-year evaluation period, and increase to between 38 and 46% of total life cycle costs over the 50-year period, due to filter media bed rehabilitation costs assumed to be required after 25 years of operation. | + | Below are capital and life cycle cost estimates for the three [[bioretention]] configurations over 25- and 50-year time periods. The estimates of maintenance and rehabilitation (life cycle) costs represent net present values. Operation and maintenance costs are predicted to represent between 25 and 31% of total life cycle costs over the 25-year evaluation period, and increase to between 38 and 46% of total life cycle costs over the 50-year period, due to filter media bed rehabilitation costs assumed to be required after 25 years of operation. |