Cost-benefit considerations for bioretention

General cost etimation methods can be used by site planners to compare the relative construction and maintenance costs for structural BMPs. However, it is recommended that construction and maintenance budgets should be based on site specific information. Once the construction plans are created, designers could use the table below and the cost estimation worksheet. The table below lists the site components that are specific to bioretention practices. Not included in this table are those cost items that are common to all construction projects, such as mobilization, traffic control, erosion and sediment control, permitting, etc.

This table shows cost Components for Bioretention Practices
(Link to this table)

Implementation Stage	Primary Cost Components	Basic Cost Estimate	Other Considerations
Site Preparation	Tree & plant protection	Protection Cost ($/area) x Affected Area	Removal of existing structures, topsoil removal and stockpiling
	Clearing & grubbing	Clearing Cost ($/area) x Affected Area	Removal of existing structures, topsoil removal and stockpiling
	Topsoil salvage	Clearing Cost ($/area) x Affected Area	Removal of existing structures, topsoil removal and stockpiling
Site Formation	Excavation / grading	4-ft Depth Excavation Cost ($/acre) x Area (acre)	Soil & rock fill material, tunneling
	Hauling material offsite	Excavation Cost x (% of Material to be hauled away)	Soil & rock fill material, tunneling
Structural Components	Under-drains	Under-drain cost ($/lineal foot) x length of device	Pipes, catch-basins, manholes, valves
	Inlet structure	($/structure) or ($/curb cut)	Pipes, catch-basins, manholes, valves
	Outlet structure	($/structure)	Pipes, catch-basins, manholes, valves
	Liner	Liner cost ($/square yard) x area of device)	Pipes, catch-basins, manholes, valves
Site Restoration	Filter strip	Sod cost ($/square foot) x filter strip area	Tree protection, soil amendments, seed bed preparation, trails
	Soil preparation	Topsoil or amendment cost ($/acre) x Area (acre)	Tree protection, soil amendments, seed bed preparation, trails
	Seeding	Seeding Cost ($/acre) x Seeded Area (acre)	Tree protection, soil amendments, seed bed preparation, trails
	Planting / transplanting	Planting Cost ($/acre) x Planted Area (acre)	Tree protection, soil amendments, seed bed preparation, trails
Annual Operation, Maintenance, and Inspection	Debris removal	Removal Cost ($/acre) x Area (acre) x Frequency	Vegetation maintenance, cleaning of structures
	Sediment removal	Removal Cost ($/acre) x Area (acre) x Frequency	Vegetation maintenance, cleaning of structures
	Weed control	Labor cost ($/hour) x Hours per visit x Frequency	Vegetation maintenance, cleaning of structures
	Inspection	Inspection Cost ($) x Inspection Frequency	Vegetation maintenance, cleaning of structures
	Mowing	Mowing Cost ($) x Mowing Frequency	Vegetation maintenance, cleaning of structures