Environmental Engineering Reference
In-Depth Information
Table 2.2 Summary of Cost Comparisons Between Conventional and
LID Approaches
Conventional
Cost
Percent
Project
Development Cost
LID Cost
Difference
Difference
2
nd
Avenue SEA
Street
$868,803
$651,548
$217,255
25%
Aubum Hills
$2,360,385
$1,598,989
$761,396
32%
Bellingham City
Hall
$27,600
$5,600
$22,000
80%
Bellingham Bloedel
Donovan Park
$52,800
$12,800
$40,000
76%
Gap Creek
$4,620,600
$3,942,100
$678,500
15%
Garden Valley
$324,400
$260,700
$63,700
20%
Laurel Springs
$1,654,021
$1,149,552
$504,469
30%
Mill Creek
a
$12,510
$9,099
$3,411
27%
Pairie Glen
$1,004,848
$599,536
$405,312
40%
Somerset
$2,456,843
$1,671,461
$785,382
32%
Tellabs Corporate
Campus
$3,162,160
$2,700,650
$461,510
15%
Source: LowImpactDevelopment (LID)StrategiesandPractices, USEPA, 2007
a
Mill Creek costs are reported on a per-lot basis.
• At the site level, significant cost savings can be achieved from clustering,
including costs for clearing and grading, stormwater and transportation
infrastructure, and utilities.
• Installation costs can be between $4,400 and $8,850 cheaper per acre for
natural landscaping than for turf grass approaches.
• Maintenance cost savings range between $3,950 and $4,583 per acre,
per year over 10 years for native landscaping approaches over turf grass
approaches.
• While conventional paving materials are less expensive than conservation
alternatives, porous materials can help total development costs go down,
sometimes as much as 30 percent by reducing conveyance and detention
needs.
• Swale conveyance is cheaper than pipe systems.
• Costs of retention or detention cannot be examined in isolation, but must
instead be analyzed in combination with conveyance costs, at which point
conservation methods generally have a cost advantage.
• Green roofs are currently more expensive to install than standard roofs, yet
costs are highly variable and decreasing. Green roofs also have significant
cost advantages when looking at life cycle costs (e.g., building, heating,
and cooling costs).
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