Eau Gallie River & Elbow Creek — Muck Dredging & Environmental Restoration
July 29, 2014 Background • 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 Project Introduction • 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 Location
4 Project Overview
5 Project Introduction (Overview) Ballard Park a) Overview b) Background
6 Eau Gallie Control Dam a) Overview b) Background
Eau Gallie Control Dam
7 Eau Gallie Control Dam
8 Eau Gallie Yacht Basin
9 Waterline Marina
10 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
14 Project Methods
• Define the magnitude of the problem • Identify desired post-dredging conditions • Document project assumptions • Develop a detailed scope of work
Ballard Park Boat Ramp
15 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
16 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
17 Sediment Characteristics • 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
18 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)
19 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 Dredging Plan
21 Bathymetric & Geotechnical
22 Sediment Shoaling Rates • 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
Dredging Template
24 Sediment Bulking Factor • 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
25 DMMA Investigation • 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
26 DMMA Site Locations
27 Typical DMMA Plan
28 Total Project Cost Estimate
City of Florida Washington Line Project Element FIND Sites Melbourne Recyclers Park
1 Permitting $749,000 $514,000 $533,000 $533,000
Construction 2 $717,500 $939,500 $857,500 $832,500 (Engineering) Construction 3 $18,821,250 $15,559,750 $15,860,000 $14,938,750 (Contractor)
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
29 Estimated Project Schedule
City of Florida Washington Services (Months) FIND Sites Melbourne Recyclers 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
30 Option Comparison Matrix
City of Florida Washington Line Evaluation Factor FIND Sites Melbourne Recyclers 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 31 Future Tasks • Project funding & DMMA • Regulatory agency permits • Final construction documents • Bidding assistance & contractor selection • Project construction & DMMA site restoration • Project closeout & certification
32 Questions?
33 Estimated Project Schedule (Construction Windows)
City of Florida Washington Services (Months) FIND Sites Melbourne Recyclers 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
34 Cost Estimate – Permitting
Line Engineering Services FIND Sites City of Melbourne Florida Recyclers Washington Park
Geotechnical & P-1 $527,000 $377,000 $391,000 $391,000 Surveying
Seawall, Dock, & P-2 $72,000 $72,000 $72,000 $72,000 Shoreline Condition
Environmental Impact P-3 $30,000 $20,000 $22,000 $22,000 Avoidance
Booster Pump & P-4 $88,000 $13,000 $16,000 $16,000 Pipeline Routes
Regulatory Agency P-5 $32,000 $32,000 $32,000 $32,000 Dredging Permits
TOTAL COST $749,000 $514,000 $533,000 $533,000
35 Cost Estimate – Preparation & Observation
Line Engineering Services FIND Sites City of Melbourne Florida Recyclers Washington Park
Booster Pump & CE-1 $300,000 $47,000 $65,000 $65,000 Pipeline Route Geotechnical & CE-2 $- $125,000 $150,000 $225,000 Surveying Services
CE-3 Final Site Design $- $150,000 $175,000 $200,000
Final Construction CE-4 $65,000 $65,000 $65,000 $65,000 Documents Bidding Assistance CE-5 $18,000 $18,000 $18,000 $18,000 Contractor Selection Construction CE-6 $325,000 $525,000 $375,000 $250,000 Observation Project Closeout & CE-7 $9,500 $9,500 $9,500 $9,500 Certification
TOTAL COST: $717,500 $939,500 $857,500 $832,500 36 Cost Estimate – Construction
City of Line Contractor Services FIND Sites Florida Recyclers Washington Park Melbourne Site Acquisition C-1 $- $730,000 $1,160,000 $820,000 (BCPA Assessment) Mobilization / C-2 $2,750,000 $2,610,000 $1,870,000 $1,870,000 Demobilization C-3 Site Construction $- $1,250,000 $2,600,000 $3,200,000 Mitigation & Monitoring C-4 $- $- $- $277,500 (Wetland Impacts) Booster Pump Water C-5 $180,000 $56,000 $80,000 $80,000 Collection System C-6 Hydraulic Dredging $10,373,750 $9,132,500 $8,316,250 $8,003,750 Dredging Flocculants & C-7 $937,500 $1,406,250 $468,750 $312,500 Coagulants C-8 Dredge Offloading $1,955,000 $- $575,000 $- Final Disposal of Dredged C-9 $1,875,000 $- $390,000 $- Material 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 37 Hydraulic Dredge Mechanical Dredge FIND Site BV-52
40 FIND Site BV-40
41 City of Melbourne
42 Florida Recyclers of Brevard
43 Brevard County
44