Island Feasibility Study Presentation for the Tampa Bay Regional - - PowerPoint PPT Presentation

Weedon Island Feasibility Study

Presentation for the Tampa Bay Regional Planning Council Agency

• n Bay Management –

August 9, 2018

Project Background

 SWFWMD / County Cooperative Funding

Initiative

 2012 Weedon Island Preserve

Management Plan

 Goals and Objectives

 Habitat Restoration and Improvement  Hydrologic Preservation and Restoration  Exotic and Nuisance Species Management

 Evaluate Habitat Restoration/Enhancement

Projects

 Existing and Proposed Site Conditions  Permitablitiy  Costs – Measurable Benefits

Weedon Island Preserve

 3,190-acre preserve

 Study area 1,100-acres

 Mangrove forest habitat dominates the landscape

 Maritime hammock  Salterns  Salt marsh  Scrubby flatwoods  Seagrass

 Significant cultural and historical resources present

 Shell middens  Domiciliary mounds  Sand burial mounds

Weedon Island Preserve

 Mosquito Ditching in 1950’s

1943 1958 1970

Feasibility Study

 Goals

 Habitat Restoration and Improvement

 Restore saltern, mangrove, and salt marsh communities  Improve habitats by removing upland spoil mounds and improving circulation  Natural resource management practices such as prescribed fire

 Exotic and Invasive Species Management and Control

 Reduce the extend and abundance of exotic and invasive plants

 Hydrologic Preservation and Restoration

 Improve hydrology to improve water quality and circulation

Feasibility Study

 Objectives

 Increase Wetland Habitat Area  Improve Native Wetland Plant Communities

 Removal of upland spoil mounds  Nuisance species removal  Hydrology improvements

 Decrease nuisance species cover in both upland and wetland habitats

by various methods of control

 Identify project approaches that will not adversely affect cultural and

historical resources within the study area

Feasibility Study

 Constraints

 Significant Cultural and Historical Resources  Access Issues

 Cover type  Distance from uplands or open water  Lack of survey

 Permit Complexity  Performance Criteria  Public Involvement

Restoration and Enhancement Approach

 Spoil Mound Removal  Nuisance Species Removal

 Focused, complete effort in larger areas of nuisance species  Selectively remove scattered nuisance species

 Hydrology Improvements

 Improve flushing and natural tidal regimes

Study Units

 Based on changes in community and natural features  Allow assessment of:

 Access restrictions  Cultural Resources  Permit complexity

 Low, moderate, or high ranking assigned

Study Units

Spoil Mound Removal

Study Units

Nuisance Species Removal

Study Units

Hydrology Improvements

Study Units

Fire Units

Spoil Mound Removal - Hydroblasting

 The process of moving soil with pressurized water

 Portable water pumps  Specialized hoses  Blast mounds of spoil  Direct resulting slurry into existing mosquito ditches

 Requires removal of nuisance species prior to Hydroblasting

 Follow-up recommended

 Grade lowered to that of surrounding wetland  Methodology yields mixed results

 Amount of material removed  Elevation achieved  Type of soil remaining

Photo courtesy of SWFWMD

Spoil Mound Removal - Hydroblasting

Unit ID Unit Acreage Cost Estimate (by Unit Acreage) Unit Access Restrictions Cultural Resources Permit Complexity

SMR-1 2.62 $19,925 Low Low Low SMR-2 25.18 $191,494 Low Low Low SMR-3 8.94 $67,989 Low Low Low SMR-4 5.91 $44,946 Low Moderate/Low Moderate SMR-5 8.02 $90,225 Moderate High High SMR-6 6.89 $52,398 Low High High SMR-7 6.49 $146,025 High High High SMR-8 12.35 $138,938 Moderate Low Low SMR-9 17.24 $193,950 Moderate Low Moderate SMR-10 11.27 $253,575 High High High SMR-11 20.51 $155,979 Low High High SMR-12 43.23 $328,764 Low High High SMR-13 15.34 $268,327 Low Low Low SMR-14 12.62 $220,749 Low Low Low SMR-15 18.62 $481,793 Moderate Moderate/Low Low/Moderate SMR-16 17.09 $298,938 Low Moderate/Low Low/Moderate SMR-17 16.30 $421,763 Moderate Moderate/Low Moderate SMR-18 12.47 $645,323 High Low Moderate/High SMR-19 18.63 $325,876 Low Low Moderate SMR-20 18.15 $469,631 Moderate Low High SMR-21 16.00 $414,000 Moderate Low High SMR-22 15.68 $405,720 Moderate Low High SMR-23 14.09 $729,158 High Low High SMR-24 13.90 $719,325 High Low High SMR-25 20.61 $533,284 Moderate Low High SMR-26 13.93 $720,878 High Low High SMR-27 13.74 $355,523 Moderate Low Moderate SMR-28 13.39 $234,218 Low Low Moderate TOTALS 419.21 $8,928,710 South Spoil Mound Removal Study Units North Spoil Mound Removal Study Units

 Per Mound

 Low - $1,690  Mid - $2,500  High - $5,000

 Estimated

 Mound Size  Number per Acre

 419 Acres  $8.93 M  $21,310 per Acre

Spoil Mound Removal – WIDO

 “Walk In, Dig Out” (WIDO)

 Includes temporary access roads

(Walk In)

 Spoil mound removal to create

the temporary fill

 Crane mats to reduce the

amount of fill used

 Temporary pipes to maintain

flow

Spoil Mound Removal – WIDO

 “Walk In, Dig Out” (WIDO)

 Longer-term temporary access

roads

 Removed in phases

Spoil Mound Removal – WIDO

 Long reach, amphibious

excavators

 Spoil used to selectively

fill mosquito ditches

 Or, hauled away

Spoil Mound Removal – WIDO

 Dig the access road out (Dig Out)  Removal of remaining spoil

mounds

 Restoration of temporarily-

impacted mangrove habitat

 Fill backwater ditches  Hydrology Improvements

 Improve Diurnal Flow  Deeper-water Refugia

Spoil Mound Removal - WIDO

Square Feet Acreage Spoil Mounds 83,457 1.9 13.0% Black Mangroves 381,517 8.8 59.4% Red Mangroves/Mosquito Ditches 177,000 4.1 27.6% TOTAL AREA 641,974 14.7 100% Square Feet Acreage Access Road Impacts (fill) 74,620 1.7 11.6% Mosquito Ditch Impacts (fill) 7,172 0.2 1.1% Mosquito Ditch Impacts (dredge) 170,527 3.9 26.6% TOTAL TEMPORARY IMPACTS 252,319 5.8 39.3% Square Feet Acreage Black Mangroves Not Impacted 306,198 Restored Black Mangrove Temporary Impacts 74,620 Removed Spoil Mounds 64,022 Black Mangroves (Total) 444,840 10.2 69.3% Red Mangroves/Mosquito Ditches Restored 129,360 3.0 20.2% Deeper Water Refugia 41,167 0.9 6.4% Saltern/High Marsh 26,607 0.6 4.1% TOTAL AREA 641,974 14.7 100.0% Size Cover Type % Existing Conditions

Table 4-3 Sample Work Area

Temporary Impact Quantities Proposed Conditions Size Cover Type % Size Work Area %

WIDO Results

 Restored temporary impacts  Filled backwater ditches  Removed all nuisance species’

habitat

 Hydrology Improvements

 Improved diurnal flow  Created refugia

Spoil Mound Removal - WIDO

Cost Type Cost Cost per month 42,000 Manhours 10,000 Fuel 3,500 Maintenance 4,200 Total Cost 59,700 $ Cost Type Cost Cost per month 10,000 manhours 6,000 160 hours, $15 / hr, 2.5 multiplier Fuel 1,680 Maint 1,000 Total Cost 18,680 $ Cost Type Cost Cost per month 2,315 manhours 6,000 Fuel 1,680 Maint 232 Total Cost 10,227 $ Cost Total Cost 10,000 $ 160 hours, $25 / hr, 2.5 multiplier Rate Type Front-end loader Rate Type Foreman 10% rental rate rental rate 160 hours, $15 / hr, 2.5 multiplier 24 gal/day @$3.50/gal 24 gal/day @$3.50/gal 10% rental rate

Table B-2 Equipment Cost Estimate

Rate Type Amphibious Excavator Off-Road Articulating Truck Rate Type rental rate rental rate 160 hours, $25 / hr, 2.5 multiplier 50 gal/day @$3.50/gal 10% rental rate

Spoil Mound Removal – WIDO

Cost Type Cost Amphibious Excavator 59,700 Truck 18,680 Front-end Loader 10,227 Foreman 10,000 98,607 $ 4,930 $ Cost Type Days Cost Comment Main Access Road 1.1 5,423 1000 feet per day Spur Access Road 4.8 23,666 720 feet per day Long Reach Spoil Removal 12.0 59,164 6 mounds per day Fill Ditch 1.5 7,395 240 feet per day Dredge Ditch 3.9 19,228 350 feet per day Dig Out 4.8 23,666 720 feet per day removal TOTAL 28.1 138,542 $ Cost Type Quantity temporary pipe 140 2,800 crane mats 10 5,000 TOTAL $ 7,800 Cost Type Quantity Erosion Control 10% 14,634 $ Overhead 30% 43,903 $ Mobilization 10% 14,634 $ Contingency 10% 13,197 $ 86,368 $ TOTAL 232,710 $ PER ACRE 15,831 $ Cost Other Incidentals (Reusable) Cost Construction Time per month per day

Table B-3 WIDO Cost Estimate

Equipment Plus Labor

Spoil Mound Removal - WIDO

Unit ID Size (Acre) Price per Acre Cost per Study Unit Cultural Resources Permit Complexity

SMR-1 2.62 15,831 $ $41,477 Low Low SMR-2 25.18 15,831 $ $398,625 Low Low SMR-3 8.94 15,831 $ $141,529 Low Low SMR-4 5.91 15,831 $ $93,561 Moderate/Low Moderate SMR-5 8.02 15,831 $ $126,965 High High SMR-6 6.89 15,831 $ $109,076 High High SMR-7 6.49 15,831 $ $102,743 High High SMR-8 12.35 15,831 $ $195,513 Low Low SMR-9 17.24 15,831 $ $272,926 Low Moderate SMR-10 11.27 15,831 $ $178,415 High High SMR-11 20.51 15,831 $ $324,694 High High SMR-12 43.23 15,831 $ $684,374 High High SMR-13 15.34 16,244 $ $249,183 Low Low SMR-14 12.62 16,244 $ $204,999 Low Low SMR-15 18.62 16,244 $ $302,463 Moderate/Low Low/Moderate SMR-16 17.09 16,244 $ $277,610 Moderate/Low Low/Moderate SMR-17 16.30 16,244 $ $264,777 Moderate/Low Moderate SMR-18 12.47 16,244 $ $202,563 Low Moderate/High SMR-19 18.63 16,244 $ $302,626 Low Moderate SMR-20 18.15 16,244 $ $294,829 Low High SMR-21 16.00 16,244 $ $259,904 Low High SMR-22 15.68 16,244 $ $254,706 Low High SMR-23 14.09 16,244 $ $228,878 Low High SMR-24 13.90 16,244 $ $225,792 Low High SMR-25 20.61 16,244 $ $334,789 Low High SMR-26 13.93 16,244 $ $226,279 Low High SMR-27 13.74 16,244 $ $223,193 Low Moderate SMR-28 13.39 16,244 $ $217,507 Low Moderate TOTALS 419.21 $6,739,995 Southern Portion of Preserve Northern Portion of Preserve

 419 Acres  $6.74 M  $16,078 / Acre

Similar Restoration Efforts

 Mosquito Lagoon, Canaveral National Seashore Dragline

Ditch Restoration

 St. John’s Water Management District  Volusia County Mosquito Control  National Park Service  Florida Fish and Wildlife Conservation Commission  U.S. Fish and Wildlife Service

 $1,375/Acre  District Staff  No Survey  No Material

Hauling

 40% Wetland

Acreage Restored

Mosquito Lagoon

Nuisance Species Removal

 Hydro-axe  Roller Chop  Herbicide (Bower Tract)  Quarterly maintenance events for

three years

 Foliar Spray  Basal Spray  Hack and Squirt

 Chainsaw  Prescribed Burn

Brazilian Pepper Signature

Nuisance Species Removal

 Non-ditched Areas

 Average - $273 per Acre

 Ditched Areas

 Average - $2,429 per acre

 419 Acres  $1.02 M

Cost (Total) Size (Acres) Cost (Per Acre) Referenced Project Non-Mosquito Ditched Areas 500 1 500 Foliar Spray 2000 9 222 9800 102 96 273 $ Average Mosquito Ditch Mangroves Bower Tract 9,800 initial 102 acres 100,440 3 years quarterly 110,240 $ Total 1,081 $ per acre Feather Sound 10,000 initial Feather Sound 9 acres 24,000 3 years quarterly 34,000 $ Total 3,778 $ per acre 2,429 $ Average Bower Tract Herbicide Table B-4 Nuisance Species Removal Cost Estimate FDOT District -Wide Contract Feather Sound Bower Tract

Hydrology Improvements

 Mosquito ditch filling  Dead-end ditch/berm

• penings

 Pipe desilting  Ditch dredging

Recommended Approach

Approach Size (Acre) Total Cost Price per Acre

Hydrology Improvement

• 148,348

$

• Hydroblasting

14.51 236,250 $ $16,282 Nuisance Species Removal 246.19 68,299 $ $406 Nuisance Species Removal and Prescribed Burn 262.32 73,049 $ $278 Nuisance Species Removal, Prescribed Burn, and Hydrology Improvements 6.89 19,550 $ $2,837 Nuisance Species Removal and Hydrology Improvement 63.74 287,380 $ $4,509 Walk In, Dig Out 306.11 4,742,448 $ $15,493 Walk In, Dig Out and Hydrology Improvements 27.96 520,460 $ $18,614 Walk In, Dig Out, Nuisance Species Removal, and Hydrology Improvements 6.89 146,760 $ $21,300 TOTALS 934.61 6,242,545 $ $6,679

Measurable Benefits

 Uniform Mitigation Assessment Methods (UMAM)

 Relative Functional Gain (RFG) = 132.3 units  Temporary Impacts – Functional Loss (FL) = 21.9 units  Net RFG = 110.4 units  Mitigation Bank @ $100K per Acre = $11.04 M ecological lift  Cost = $6.24 M < $11.04 M

Project Schedule

 Final Report - September 2018  Pilot Project – 27.96 acres, $454,182

 Cooperative Funding Initiative Application - October 2019  Design and Permitting – October 2020  Construction – October 2021

 Repeat (10 to 15 years)

Stakeholders

 Pinellas County  SWFWMD  Tampa Bay Estuary Program  Tampa Bay Regional

Planning Council

 USGS  Alliance for Weedon Island

Archaeological Research

 Friends of Weedon Island  Duke Power

Questions?