The section on integrated stormwater management outlines a cost estimation method which site planners could use to compare the relative construction and maintenance costs for structural best management practices. These curves are excellent for purposes of comparison; however, it is recommended that construction and maintenance budgets should be based on site specific information. Utilizing the cost estimation worksheet below will allow designers to avoid over or under estimation of fixed costs.

Infiltration trench and infiltration basin cost estimate worksheet.
Link to this table

Project Title
Project Number
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
Infiltration area protection - silt fence lineal foot $2.00 $0.00
Topsoil - 6" depth, salvage on site square yard $4.50 $0.00
Site Formation
Excavation - 6' depth square yard $8.00 $0.00
Grading square yard $1.50 $0.00
Hauling off-site - 6' depth square yard $10.00 $0.00
Structural Components
Inlet structure each $1,500.00 $0.00
Multi-stage outlet structure each $2,500.00 $0.00
Site Restoration
Sod filter strip lineal foot $1.50 $0.00
Soil preparation square yard $5.00 $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 $2.00 $0.00
Subtotal $0.00
10% Contingencies $0.00
Subtotal $0.00
Apply MN Location Factor $0.00
Annual Operation and Maintenance
Replace planting media square yard $12.00 $0.00
Debris removal per visit $50.00 $0.00
Mow filter strips per visit $50.00 $0.00
Sediment removal per year $500.00 $0.00
Replace plants per plant $5.00 $0.00
Erosion repair square yard $75.00 $0.00
Gate / valve operation per visit $125.00 $0.00
Inspection per visit $125.00 $0.00
Subtotal $0.00
Apply MN Location Factor $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

The table below lists the specific site components that are specific to infiltration 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.

Summary of infiltration practices cost components.
Link to this table

Implementation Stage Primary Cost Components Basic Cost Estimate Other Considerations
Site Preparation Tree & plant protection Protection Cost ($/acre) * Affected Area (acre) Removal of existing structures, topsoil removal and stockpiling
Infiltration area protection Silt fence cost ($/’foot) * Perimeter of infiltration area
Clearing & grubbing Clearing Cost ($/acre) * Affected Area (acre)
Topsoil salvage Salvage Cost ($/acre) * Affected Area
Site Formation Excavation / grading X-ft Depth Excavation Cost ($/acre) * Area (acre) Soil & rock fill material, tunneling
Hauling material offsite Excavation Cost * (% of Material to be hauled away)
Structural Components Vault structure (for underground infiltration) ($/structure) Pipes, catchbasins, manholes, valves, vaults
Media (for infiltration trenches) Media cost ($/cubic yard) * filter volume (cubic yard)
Geotextile Geotextile cost ($/cy) * area of trench, including walls
inlet structure ($/structure)
Overflow structure ($/structure)
Observation well ($/structure)
Site Restoration Soil preparation Topsoil or amendment cost ($/acre) * Area (acre) Tree protection, soil amendments, seed bed preparation, trails
Seeding Seeding Cost ($/acre) * Seeded Area (acre)
Filter strip Sod cost ($/square foot) * filter strip area
Planting / transplanting Planting Cost ($/acre) * Planted Area (acre)
Annual Operation, Maintenance, and Inspection Sediment removal Removal Cost ($/acre) * Area (acre) * Frequency (1 time per 5 years) Vegetation maintenance, cleaning of structures
Debris removal Removal Cost ($/acre) * Area (acre) * Frequency (2 time per year)
Inspection Inspection Cost ($) * Inspection Frequency (6 times per year)
Mowing (for some vegetative filters) Mowing Cost ($) * Mowing Frequency (6 times per year)

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This page was last edited on 25 August 2016, at 21:14.


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