Cost-benefit considerations for filtration
Cost estimates that site planners can use to compare the relative construction and maintenance costs for structural best management practices are excellent for purposes of comparison. However, it is recommended that construction and maintenance budgets should be based on site specific information. Utilizing the table below and cost estimation worksheets for either bioretention or surface sand filter will allow designers to more accurately estimate the cost of a filtration BMP.
Cost components for filtration practices.
Link to this table
| Implementation Stage | Primary Cost Components | Basic Cost Estimate | Other Considerations |
|---|---|---|---|
| Site Preparation | Tree & plant protection | Protection Cost ($/acre) x Affected Area (acre) | Removal of existing structures, topsoil removal and stockpiling |
| Topsoil salvage | Salvage cost ($/acre) x Affected Area (acre) | ||
| Clearing & grubbing | Clearing Cost ($/acre) x Affected Area (acre) | ||
| Site Formation | Excavation / grading | X-ft Depth Excavation Cost ($/acre) x Area (acre) | Soil & rock fill Hauling material material, tunneling |
| Hauling material offsite | Excavation Cost x (% of Material to be hauled away) | ||
| Structural Components | Under-drains | Under-drain cost ($/lineal foot) x length of device | Pipes, catchbasins, manholes, valves, vaults |
| Vault structure (for media filters) | ($/structure) | ||
| Media (for media filters) | Media cost ($/cubic yard) X filter volume (cubic yard) | ||
| Inlet structure (for vegetative filters | ($/structure) | ||
| Outlet structure (for vegetative filters) | ($/structure) | ||
| Site Restoration | Filter strip | Sod cost ($/square foot) x filter strip area | Tree protection, soil amendments, seed bed preparation, trails |
| Soil preparation | Topsoil or amendment cost ($/acre) x Area (acre) | ||
| Seeding | Seeding Cost ($/acre) x Seeded Area (acre) | ||
| Planting / transplanting | Planting Cost ($/acre) x Planted Area (acre) | ||
| Annual Operation, Maintenance, and Inspection | Debris removal | Removal Cost ($/acre) x Area (acre) x Frequency (2x / 1yr) | Vegetation maintenance, cleaning of structures |
| Sediment removal | Removal Cost ($/acre) x Area (acre) x Frequency (1x / 5yr) | ||
| Gate / valve operation | Operation Cost ($) x Operation Frequency (2x / 1 yr) | ||
| Inspection | Inspection Cost ($) x Inspection Frequency (6x / 1 yr) | ||
| Mowing (for some vegetative filters) | Mowing Cost ($) x Mowing Frequency (4x / 1 yr) |
- Overview for filtration
- Types of filtration
- Design criteria for filtration
- Construction specifications for filtration
- Assessing the performance of swales
- Assessing the performance of sand filters
- Operation and maintenance of filtration
- Calculating credits for sand filter
- Calculating credits for swale
- Cost-benefit considerations for filtration
- References for filtration
Surface sand filter 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 - 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 | ||||
| Underdrain - with pea gravel and geotextile | lineal foot | $400.00 | $0.00 | |
| Inlet structure | each | $1,500.00 | $0.00 | |
| Sand filter media - 18" depth | square yard | $15.00 | $0.00 | |
| Outlet structure | each | $3,000.00 | $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 | |
| 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 | |
| Mowing | per visit | $150.00 | $0.00 | |
| Sediment removal | per yeart | $500.00 | $0.00 | |
| Gate / valve operation | per visiit | $125.00 | $0.00 | |
| Erosion repair | square yard | $75.00 | $0.00 | |
| Inspection | pper visitt | $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