Changes

==Life Cycle Costs==

==Life Cycle Costs==

Below are capital and life cycle cost estimates for the two [[Infiltration trenches|infiltration trench]] 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 38% of total life cycle costs over the 25-year evaluation period, and increase to 51% of total life cycle costs over the 50-year period, due to increased levels of litter removal, replacement of filter cloth and disposal of collected sediment (every 4 - 8 years), cleaning out the catchbasin and the [[Oil and Grit Separator|Oil and Grit Separator/Hydrodynamic Separator]] annually, as well as flushing inlet, distribution and outlet pipes every 10 years.  

Below are capital and life cycle cost estimates for the two [[Infiltration trenches|infiltration trench]] 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 37 and 39% of total life cycle costs over the 25-year evaluation period, and increase to 52% of total life cycle costs over the 50-year period, due flushing of inlet, distribution and outlet pipes every 10 years.