Table 3 Unit cost and benefit of marsh-fronted seawall in $2023USD

From: Marsh restoration in front of seawalls is an economically justified nature-based solution for coastal protection

Category

Source

$2023USD

Units

Costs

Marsh planting costs

 All

USACE, 201561

2.82

($/planting(1))

Marsh capital costs (Marshland creation, stabilization)(2)

 Low

Narayan et al.21

1.54

($/m2)

 Medium

Oppenheimer et al.64

9.37

($/m2)

 High

Linham et al.59

9.68

($/m2)

Other costs

Contingency

 All

USACE, 201561

25%

(of capital cost)

Engineering and design

 All

USACE, 201561

12%

(of capital cost)

Construction management

 All

USACE, 201561

10%

(of capital cost)

Marsh maintenance costs

 All

Linham et al.59

0.15

($/m2/year)

 All

USACE, 201561

0.50%

(of capital cost)

Benefits

Reduced seawall heightening

 Low

Linham et al.59

1129

($/m/m)

 Medium

Linham et al.59

8064

($/m/m)

 High

Linham et al.59

22,643

($/m/m)

Environmental services

 Low

FEMA, 202231

2.55

($/m2/year)

 Medium

Jin et al.65

4.19

($/m2/year)

 High

Jin et al.65

4.51

($/m2/year)

  1. (1) A planting is a plant plug, which consists of one or more germinated and grown salt marshes. The unit cost accounts for the purchase of plant plugs and labor installation on the marshland.
  2. (2) Marsh creation and stabilization is the ground and earthworks preparation to grow salt marsh habitat.
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