Eau Gallie River & Elbow Creek — Muck Dredging & Environmental Restoration

July 29, 2014

• Indian River Lagoon (IRL)

o 156 miles long

o Six coastal counties

• North America’s most diverse estuary

• IRL Economic Assessment & Analysis (2007)

o $3.7 billion in benefits overall

2

Background

• Muck deposits within the IRL, the Eau Gallie River, & Elbow Creek negatively affect: o Water quality & natural resources o Shoals within the waterbodies o Navigability of the waterbodies o Recreational activities & property values

3

Project Introduction

4

Project Location

Project Overview

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Project Introduction (Overview)

a) Overview b) Background

Ballard Park

6

Eau Gallie Control Dam

a) Overview b) Background

Eau Gallie Control Dam 7

Eau Gallie Control Dam

8

9

Eau Gallie Yacht Basin

10

Waterline Marina

Project Objectives Phase I • Dredging Feasibility Study

• Conceptual Dredging Plans

• Order of Magnitude Cost Estimates

11

Project Objectives Phase II • Funding

• Final Data Collection & Permitting

• Final Plans & Specification

• Bid Documents

12

Project Objectives Phase III • Construction

13

Phase I • Dredging Feasibility Study

o Permitting

o Construction

• Conceptual Dredging Plans

• Detailed Order of Magnitude Cost Estimates

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Project Methods

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Ballard Park Boat Ramp

• Define the magnitude of the problem

• Identify desired post-dredging conditions

• Document project assumptions

• Develop a detailed scope of work

Project Permits • Dredging and DMMA construction

will require permits

o U. S. Army Corps of Engineers (USACE)

o FDEP

o City of Melbourne

o Brevard County

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Project Assumptions • Exclude mechanical dredging

• Florida Fish & Wildlife Conservation Commission (FFWCC) seasonal Manatee dredging restrictions

• May require future sediment chemistry testing

• Minimal bathymetric & geotechnical data collection for verification purposes

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Sediment Characteristics

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• Physical characteristics of muck sediment

o Average solids content of ~24%

o Specific gravity of 2.43

o Settling test results ranged from 10% to 30% after 30 days

o Muck sediment dewatering will likely require binding agents

Bathymetric & Geotechnical

• Data from 2000, 2005, & 2013 bathymetric surveys

• 30 cross sections for each top of muck layer

• Probed the muck thickness in the general vicinity of deepest probe for previously collected cross-sectional data (2000)

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Bathymetric & Geotechnical

• Created DTM for the 2000, 2005, & 2013 surveys

o Top of the muck layer for each year

o Bottom layer based on 2000 survey

• Compared the DTM data

o In 2000 average muck thickness of 7.5 ft

o In 2005 average muck thickness of 8.3 ft

o In 2013 average muck thickness of 9.6 ft 20

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Dredging Plan

Bathymetric & Geotechnical

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• Average shoaling rate of 3,300 cy/yr

• District should anticipate higher shoaling rates, especially for the 1st & 2nd maintenance dredging

o Dredging template exclusions

o Watershed is 79.5% urban & residential

o Increased currents & velocities

o Easterly winds transport muck from the IRL 23

Sediment Shoaling Rates

• Initial shoaling rate of 7,500 & 17,500 cy/yr for the first & second maintenance cycles

• Sustainable shoaling rate of 5,000 & 15,000 cy/yr

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Dredging Template

Sediment Shoaling Rates

• During dredging, in situ material will bulk due to adding water & handling the material

• Bulking factor of 1.75

• 625,000-cy dredging template requires 1,094,000-cy DMMA capacity

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Sediment Bulking Factor

• Each option involves hydraulically dredging sediments via pipeline

o Intracoastal Waterway DMMA sites

o Non-traditional dewatering at the City site

o DMMA at Florida Recyclers of Brevard site

o DMMA at the Washington Park site

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DMMA Investigation

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DMMA Site Locations

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Typical DMMA Plan

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Line Project Element FIND Sites City of

Melbourne

Florida

Recyclers

Washington

Park

1 Permitting $749,000 $514,000 $533,000 $533,000

2 Construction (Engineering) $717,500 $939,500 $857,500 $832,500

3 Construction (Contractor) $18,821,250 $15,559,750 $15,860,000 $14,938,750

4 Contingency (10%) $2,029,000 $1,701,000 $1,725,000 $1,630,000

TOTAL COST (ROUNDED): $22,300,000 $18,700,000 $19,000,000 $17,900,000

Total Project Cost Estimate

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Services (Months) FIND Sites City of Melbourne

Florida Recyclers

Washington Park

1 P-1 through P-5 10.5 10.0 10.2 11.7

2 CE-1 through CE-5 8.3 7.4 7.8 8.3

3 CE-6 through CE-7 34.2 37.4 38.4 31.1

4 C-1 through C-10 34.2 37.4 38.4 31.1

TOTAL: 53.0 54.8 56.4 51.1

Estimated Project Schedule

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Line Evaluation Factor FIND Sites City of Melbourne

Florida Recyclers

Washington Park

1 Total Project Cost 4 2 3 1

2 Total Project Schedule 2 4 3 1

3 Property Ownership 1 2 3 2

4 Construction Method 3 4 2 1

5 Maintenance Dredging Cost 4 2 3 1

Raw score 14 14 14 6

Overall Rank 2.8 2.8 2.8 1.2

Option Comparison Matrix

• Project funding & DMMA

• Regulatory agency permits

• Final construction documents

• Bidding assistance & contractor selection

• Project construction & DMMA site restoration

• Project closeout & certification

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Future Tasks

Questions?

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Estimated Project Schedule (Construction Windows)

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Services (Months) FIND Sites City of Melbourne

Florida Recyclers

Washington Park

SUBTOTAL: 53.0 54.8 56.4 51.1

HYDRAULIC DREDGING: 22.8 32.1 19.3 17.9

CONSTRUCTION WINDOWS: 18 22.5 13.5 13.5

TOTAL: 71.0 77.3 69.9 64.6

Cost Estimate – Permitting

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Line Engineering Services FIND Sites City of Melbourne Florida Recyclers Washington Park

P-1 Geotechnical & Surveying $527,000 $377,000 $391,000 $391,000

P-2 Seawall, Dock, & Shoreline Condition $72,000 $72,000 $72,000 $72,000

P-3 Environmental Impact Avoidance $30,000 $20,000 $22,000 $22,000

P-4 Booster Pump & Pipeline Routes $88,000 $13,000 $16,000 $16,000

P-5 Regulatory Agency Dredging Permits $32,000 $32,000 $32,000 $32,000

TOTAL COST $749,000 $514,000 $533,000 $533,000

Cost Estimate – Preparation & Observation

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Line Engineering Services FIND Sites City of Melbourne Florida Recyclers Washington Park

CE-1 Booster Pump & Pipeline Route

$300,000 $47,000 $65,000 $65,000

CE-2 Geotechnical & Surveying Services

$- $125,000 $150,000 $225,000

CE-3 Final Site Design $- $150,000 $175,000 $200,000

CE-4 Final Construction Documents

$65,000 $65,000 $65,000 $65,000

CE-5 Bidding Assistance Contractor Selection

$18,000 $18,000 $18,000 $18,000

CE-6 Construction Observation

$325,000 $525,000 $375,000 $250,000

CE-7 Project Closeout & Certification

$9,500 $9,500 $9,500 $9,500

TOTAL COST: $717,500 $939,500 $857,500 $832,500

Cost Estimate – Construction

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Line Contractor Services FIND Sites City of

Melbourne Florida Recyclers Washington Park

C-1 Site Acquisition (BCPA Assessment) $- $730,000 $1,160,000 $820,000

C-2 Mobilization / Demobilization $2,750,000 $2,610,000 $1,870,000 $1,870,000

C-3 Site Construction $- $1,250,000 $2,600,000 $3,200,000

C-4 Mitigation & Monitoring (Wetland Impacts) $- $- $- $277,500

C-5 Booster Pump Water Collection System $180,000 $56,000 $80,000 $80,000

C-6 Hydraulic Dredging $10,373,750 $9,132,500 $8,316,250 $8,003,750

C-7 Dredging Flocculants & Coagulants $937,500 $1,406,250 $468,750 $312,500

C-8 Dredge Offloading $1,955,000 $- $575,000 $-

C-9 Final Disposal of Dredged Material $1,875,000 $- $390,000 $-

C-10 Site Restoration & Closeout $750,000 $375,000 $400,000 $375,000

TOTAL COST: $18,821,250 $15,559,750 $15,860,000 $14,938,750

Hydraulic Dredge

Mechanical Dredge

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FIND Site BV-52

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FIND Site BV-40

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City of Melbourne

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Florida Recyclers of Brevard

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Brevard County