Costs of living shorelines versus other approaches

Living Shorelines Tech Transfer WorkshopBreakout session #5October 9, 2019 10:15a to 12:15p

Time Agenda

10:15 Welcome and intro

10:20 Participant intros Name, location, affiliationWhy you chose this sessionOne primary topic/question you’d like to have addressed

10:35 Tom Ries, President, Ecosphere Restoration Institute

10:55 Discussion Primary topic/question list Challenges and lessons learned related to LSL costs Solutions and how to implement them

12:05 Session wrap-up Summarize findings for post-lunch report

Products List of primary topics/questions List of challenges (prioritized) List of lessons learned List of solutions

Costs of Living Shorelines Depends on Multiple Factors

Eroded Natural Shoreline – Example 6’ X 100’● Vegetation Only● Short-term Protection (Fiber Log®)● Sediment Stabilization (Coconut Mat)● Sediment Stabilization (GeoWeb®)● Permanent Protection (sills – oyster bags/rock)● Access (land verses water)

Vegetation Only – Freshwater / Estuarine

Herbaceous $0.50/2”plug* 12” 600 - $300Shrubs $3.00/1-gal* 24” 150 - $450Trees $9.00/3-gal* 36” 67 - $603

• Plant material only – volunteer installation

• Example: Honi Hanta Girl Scout Camp, Bradenton, FL

Short-term Protection (Fiber Log®)

16” height 40 gage $ 90.00/100’ roll16” height 50 gage $140.00/100’ roll

Ex: River Cove Park LS

Sediment Stabilization Options (Coconut Mat)

6’ X 100’ mat $ 90.00/100’ roll

Ex: Stewart Middle School LS

Sediment Stabilization Options (GeoWeb®)

6’ X 100’ mat $ 90.00/100’ roll

Ex: Stewart Middle School LS

Permanent Protection (sills – oyster bags)

Oyster Bags $15-bag (7-bag pyramid) $320/ft

Ex: Bermuda Bay LS

Permanent Protection (sills – rock)

Rock 2’ base X 1’ height $100/linear foot

Ex: Stewart Middle School LS

Vegetation Only – Honi Hanta Girl Scout Camp

120 linear feet @ $28K ($233/linear foot)

Fiber Log® w/Vegetation @ River Cove Park

600 feet @ $ 30.00/linear foot ($18K)

Stewart Middle School Coconut Mat & GeoWeb®

1,800 linear feet @ $180K ($100/linear foot)

Bermuda Bay (sills – oyster bags)

430 feet @ $14,500 ($32/linear foot)

Safety Harbor (sills – rock & oyster bags)

80’ Rock & Oyster bags @ $150K ($1.8K/linear ft)

MAINTENANCE COST COMPARISON

Category Installation LifespanCost ($/ft)a

Atlantic and Gulf Coasts FloridaInstallation Maintenance Installation Maintenance

Green

Planting Indefinite $45-$225 10% $15-$45 10%

Oyster bags Indefinite $45-$90 10% $30-$40 10%

Living shoreline Indefinite $120-$700 10-20% $75-$500 10-20%

Hard

Revetment/rip rap 20+ years $500-$1500 50-100% $465-$1400 50-100%

Breakwater 20+ years $200-$1000 50-100% $200-$900 20-100%

Bulkhead 20+ years $265-$1022 50-100% $240-$800 50-100%

Retaining wall 20+ years$1000-$3370

50-100%$1200-$2775

50-100%

Table Range of costs to construct and maintain common shore-parallel erosion control installations. Compiled by Randall W. Parkinson (Atlantic and Gulf Coast) and Tom Ries (Florida).

Costs of Seawall Enhancements Depends on Multiple Factors

● Depth● Sediments● Energy Types (wakes, fetch, 1° direction, etc.)● Construction Access● Materials (oyster bags, rock, etc.)● Infrastructure

Design & Permitting Alternative SeawallShallow Water/Low Wake $17,625 $18,250 Shallow Water/High Wake $19,250 $19,250 Deep Water/High Wake $19,250 $19,250 Deep Water/Low Wake $15,250 $15,250

Construction Alternative SeawallShallow Water/Low Wake $64,100 $110,300 Shallow Water/High Wake $83,500 $131,100 Deep Water/Low Wake $107,960 $171,100 Deep Water/High Wake $135,120 $141,100