General cost estimation 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


Bioretention device cost estimate worksheet.
Link to this table

Project Title
Owner
Location
Project Number
Date
Description Units Quantity Unit Cost Total Estimated Price
Site Preparation
Tree removal - up to 12" diameter each $350.00 $0.00
Clear and grub brush square yard $1.50 $0.00
Tree protection - temp. fence lineal foot $3.00 $0.00
Topsoil - 6" depth, salvage on site square yard $4.50 $0.00
Site Formation
Excavation - 4' average depth square yard $10.00 $0.00
Grading square yard $1.50 $0.00
Hauling off-site square yard $5.50 $0.00
Structural Components
Underdrain - with pea gravel and geotextile lineal foot $30.00 $0.00
Inlet structure each $1,500.00 $0.00
Outlet structure each $2,500.00 $0.00
Site Restoration
Filter strip square yard $0.00 $0.00
Soil preparation square yard $30.00 $0.00
Seeding - above outlet elevation square yard $0.50 $0.00
Planting - below outlet elevation square yard $30.00 $0.00
Mulch square yard $5.00 $0.00
Subtotal $0.00
10% Contingencies $0.00
Subtotal $0.00
Apply MN Location Factor $0.00
TAL CONSTRUCTION COST $0.00
Annual Operation and Maintenance
Debris removal per visit $50.00 $0.00
Weed control per visit $50.00 $0.00
Sediment removal per yeart $500.00 $0.00
Replace planting media square yard $12.00 $0.00
Replace plants per plant $5.00 $0.00
Mow filter strips per visit $50.00 $0.00
Erosion repair square yard $75.00 $0.00
Inspection per visit $125.00 $0.00
Subtotal $0.00
Apply MN Location Factor $0.00
TOTAL ANNUAL O&M COST $0.00
Minnesota Location Factors
Bemidji 0.963
Brainerd 1.003
Detroit Lakes 0.962
Duluth 0.991
Mankato 0.990
Bemidji 0.963
Minneapolis 1.035
Rochester 0.983
St. Paul 1.000
St. Cloud 1.002
Thief River Falls 1.042
Willmar 0.961
Windom 0.935

Note: Suggested unit costs are based on RS Means prices for Spring, 2005, then factored into an area basis based on typical design features for Constructed Wetlands BMPs. To be used for preliminary cost estimation



Related pages

This page was last modified on 24 February 2016, at 15:00.

Minnesota Pollution Control Agency | 651-296-6300, 800-657-3864 | Assistance | Web site policy