management system to aid water quality …sponsors: lower susquehanna riverkeeper design of a dam...
TRANSCRIPT
Sponsors: Lower Susquehanna Riverkeeper
Design of a Dam Sediment Management System to Aid Water Quality Restoration of the Chesapeake Bay
Presented By: Sheri Gravette Kevin Cazenas Said Masoud Rayhan Ain
Faculty Advisor: George Donohue
Sediment Plume from Transient Scouring
West & Rhode Riverkeeper
Conowingo Dam
Agenda
• Context
• Stakeholders
• Problem/Need Statement
• Design Alternatives
• Analysis and Design of Simulation
• Design of Experiment
• Results, Analysis & Recommendations
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Chesapeake Bay and The Susquehanna River
• Chesapeake Bay is the largest estuary in the United States
• 3 largest tributaries of the Bay are the Susquehanna, Potomac and James rivers – Provide more than 80% of the Bay’s freshwater
• Susquehanna River is the Bay’s largest tributary – Provides nearly 50% of freshwater to the Bay
– Flows from NY to PA to MD
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Map of the Chesapeake Bay Watershed Source: The PA Dept. of Environmental Protection
Lower Susquehanna River and
Conowingo Dam
• Conowingo Dam (est. 1928) – southernmost Dam of the Lower Susquehanna
• Quality of water from the Lower Susquehanna is vital to the bay’s health
• Traps sediment and nutrients from reaching the Chesapeake Bay
– Water quality is closely related to sediment deposition
• The river provides power for turbines in hydroelectric plants and clean water to people
• Conowingo Hydroelectric Station
– Mainly provides power to Philadelphia, PA
– A black start power source
– Provides 1.6 billion kWh annually
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Map of Conowingo Reservoir Source: US Army Corps of Engineers, (2013)
Lower Susquehanna River: Steady State vs. Transient State
Transient state: river flow rate higher than 300,000 cfs
– Major Scouring event: enhanced erosion of sediment due to:
– significantly increased flow rates
– constant interaction of water with the Dam
5 Chesapeake Bay: Before and After Tropical Storm Lee Source: MODIS Rapid Response Team at NASA GSFC
Current Steady State: river flow rate less than 30,000 cfs
– Sediment/nutrients enters Chesapeake Bay at low-moderate rate
– TMDL regulations are related to steady state
Flow and Sediment Build-up in Conowingo Reservoir
Rouse Number for Medium Silt Particle at 30,000 cfs Source: S. Scott (2012)
• Rouse number defines a concentration profile of sediment – Determines how sediment will be
transported in flowing water
• Rouse Number:
𝒁 =𝝎𝒔𝒖∗
𝝎𝒔=Sediment fall velocity 𝒖∗=shear velocity
• Significant amount of suspended sediment is located directly behind the dam (areas away from
turbines)
Holtwood Dam
Conowingo Dam
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Sediment Deposition at Conowingo Dam
• Deposition potential – expected sediment deposited over a given time
• At maximum capacity all Susquehanna River sediment flow s through to the Chesapeake Bay during normal, steady-state flow
Sediment Deposition in Conowingo Reservoir; Construction to 2008 with Gap Prediction Source of Data: Hirsch, R.M., (2012)
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
0
50
100
150
200
1929 1936 1943 1950 1957 1964 1971 1978 1985 1992 1999 2006 2013 2020 2027
Percent Capacity
Sedim
ent Deposition (m
illion tons)
Year
Sediment Deposition
Expected
Threshold
Chesapeake Bay Total Maximum Daily Load (TMDL)
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• Established by US Environmental Protection Agency in conjunction with 1972 Clean Water Act
• Actively planned since 2000
• Covers 64,000 square miles in NY, PA, DE, MD, WV, VA, and DC
• Sets limits for farmers, plants, dams, and other organizations that dump sediment/nutrients into dam
• Designed to fully restore Bay by 2025 – 2017: 60% of sediment/nutrient reduction must be met
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Lower Susquehanna Contribution to TMDL
Watershed limits to be attained by 2025 are as follows:
• 93,000 tons of nitrogen per year (46% of Chesapeake TMDL reduction)
• 1,900 tons of phosphorus per year (30% of Chesapeake TMDL reduction)
• 985,000 tons of sediment per year (30% of Chesapeake TMDL reduction)
Agenda
• Context
• Stakeholders
• Problem/Need Statement
• Design Alternatives
• Analysis and Design of Simulation
• Design of Experiment
• Results, Analysis & Recommendations
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Primary Stakeholders Objective(s) Issue(s)
Lower Susquehanna Riverkeeper and Stewards of the Lower Susquehanna, Inc. (SOLs)
- Find alternative uses for the sediment stored behind Conowingo Dam
- Highlight vulnerabilities in environmental law - Minimize effects of major scouring events to
the Chesapeake Bay
- Cost to remove sediment from Reservoir is high
- Providing pressure on FERC to require more strict relicensing requirements for Conowingo Dam Hydropower Plant
Chesapeake Waterkeepers- West & Rhode Riverkeeper
- Protect and improve the health of the Chesapeake Bay and waterways in the region
- Cost to remove sediment from Reservoir is high
Maryland and Pennsylvania Residents (Lower Susquehanna Watershed)
- Maintain healthy waters for fishing and recreation
- Improve water quality of the watershed - Receive allocated power from Hydroelectric
Dam
- Cost to remove sediment from Reservoir is high
- Value low cost for power production and better water quality
Exelon Generation – owner of Conowingo Dam
- Obtain relicensing of Conowingo Dam prior to its expiration in September 2014
- Maintain profit
- Sediment build up has no impact on energy production
Federal Energy Regulatory Commission (FERC)
- Aid consumers in obtaining reliable, efficient and sustainable energy services
- Define regulations for energy providers
- Pressure to update dam regulations
Agenda
• Context
• Stakeholders
• Problem/Need Statement
• Design Alternatives
• Analysis and Design of Simulation
• Design of Experiment
• Results, Analysis & Recommendations
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Problem Statement
- Conowingo Reservoir has been retaining a majority of the sediment flowing down the Susquehanna River
- Major scouring events in the Lower Susquehanna River perpetuate significant ecological damage to the Chesapeake Bay
- This ecological damage is caused by increased deposition of sediment and nutrients in the Bay
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Need Statement
• Need to create a system to reduce the environmental impact of transient scouring events
• Need is met by reducing the sediment and nutrients currently trapped behind Conowingo Dam
– Reduce to 1,900 tons phosphorus per year
• Reduction is to be done while maintaining energy production and aiding TMDL regulations
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Mission Requirements
MR.1 The system shall remove sediment from the reservoir such that the total sediment deposition does not exceed 180 million tons.
MR.2 The system shall reduce sediment scouring potential.
MR.3 The system shall allow for 1.6 billion kWh power production annually at Conowingo Hydroelectric Station.
MR.4 The system shall facilitate Susquehanna watershed limits of 93,000 tons of nitrogen, 1,900 tons of phosphorus, and 985,000 tons of sediment per year by 2025.
MR.5 The system shall facilitate submerged aquatic vegetation (SAV) growth in the Chesapeake Bay.
Agenda
• Context
• Stakeholders
• Problem/Need Statement
• Design Alternatives
• Analysis and Design of Simulation
• Design of Experiment
• Results, Analysis & Recommendations
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Sediment Mitigation Alternatives
1. No Mitigation Techniques (Baseline) – Sediment remains in reservoir
2. Hydraulic Dredging – Sediment removed from waters
– Product made from sediment
3. Dredging & Artificial Island – Initially: Sediment is dredged to make an artificial island
– Over time: Sediment is slowly forced through the dam into bay
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Conowingo Dam Source: D. DeKok (2008)
1. No Mitigation Techniques
2. Hydraulic Dredging
3. Dredging & Artificial Island
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WHAT
• Sediment will reach capacity by 2030
• Major scouring events will have the largest impact
HOW
• Normal Flow: < 30,000 cfs
• Major Scouring Event: > 300,000 cfs
Normal Flow at Conowingo Dam Source: E. Malumuth (2012)
WHAT
• Remove sediment mechanically
• Concentration on suspended sediment
• Product yield from sediment
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3. Dredging & Artificial Island
1. No Mitigation Techniques
2. Hydraulic Dredging
Hydraulic Dredging Process Source: C. Johnson
HOW
• Rotating cutter to agitate & stir up
• Pipeline pumps sediment to surface
• Collection for further treatment
WHAT
• Diamond-shaped structure to divert water is placed in front of the dam
• Larger sediment load through the dam (at steady-state); remaining amount is dredged
HOW
• Diverter made of dredged sediment product
• Diverts water left & right – increases flow velocity
• Decreases Rouse number near suspended sediment
• Sediment mixed into wash load
• Potentially decreases total dredging costs
Potential Artificial Island Location at Conowingo Reservoir Source: Original graphic by S. Scott (2012)
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1. No Mitigation Techniques
2. Hydraulic Dredging
3. Dredging & Artificial Island
Quarry
• Direct transportation from reservoir to quarry
• No opportunity to offset cost
• No one-time investment cost
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Rock Quarry
Rotary Kiln Plasma Gas Arc Vitrification
Low Temperature Washing
3. Dredging & Artificial Island
1. No Mitigation Techniques
2. Hydraulic Dredging
Quarry
Primary Alternatives
Sub-Alternatives
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Low-Temperature Sediment Washing
• Non-thermal Decontamination
• Potential use as manufactured topsoil
• One-time cost: Approx. $25 million (BioGenesis)
• Process includes: – Loose screening – Dewatering – Aeration – Sediment washing/remediation – Oxidation and cavitation
Low Temperature Washing Facility Manufactured Topsoil
3. Dredging & Artificial Island
1. No Mitigation Techniques
2. Hydraulic Dredging
Quarry Plasma Gas Arc Vitrification
Rotary Kiln Low Temperature
Washing
Primary Alternatives
Sub-Alternatives
Rotary Kiln (Lightweight Aggregate)
• Thermal decontamination process
• Process includes: – debris removal
– Dewatering
– Pelletizing
– Extrusion of dredged material
• One-time investment cost: Approx. $180-510 million (HarborRock)
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Rotary Kiln Operation
3. Dredging & Artificial Island
1. No Mitigation Techniques
2. Hydraulic Dredging
Quarry Plasma Gas Arc Vitrification
Low Temperature Washing
Rotary Kiln
Primary Alternatives
Sub-Alternatives
• 99.99 % Decontamination and incineration of all organic compounds
• Intense thermal decontamination process
• Output: vitrified glassed compound “slag”
• One-time cost: Approx. $430 million (Westinghouse Plasma)
Plasma Gas Arc Vitrification (Glass Aggregate)
24 Glass Aggregate (Slag)
3. Dredging & Artificial Island
1. No Mitigation Techniques
2. Hydraulic Dredging
Quarry Low Temperature
Washing Rotary Kiln
Plasma Gas Arc Vitrification
Sub-Alternatives Primary Alternatives
Sub-Alternatives
Cost/Revenue ($ per cubic yard) Distribution (Triangular) Comparisons:
Quarry, Topsoil, and Lightweight Aggregate
Sources: LSRWA (Quarry); M. Lawler et al and D. Pettinelli (Topsoil); JCI/Upcycle Associates, LLC (LWA)
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3. Dredging & Artificial Island
1. No Mitigation Techniques
2. Hydraulic Dredging
00.020.040.060.080.1
0.120.140.160.180.2
$0 $50 $100 $150 $200 $250 $300
Cost/Revenue PDF (Triangular)
Lightweight Aggregate
00.020.040.060.080.1
0.120.140.160.180.2
$0 $50 $100 $150 $200 $250 $300
Cost/Revenue PDF (Triangular)
Topsoil
Revenue
Cost
00.020.040.060.080.1
0.120.140.160.180.2
$0 $100 $200 $300
Cost PDF (Triangular)
Quarry
Quarry Low Temperature
Washing Rotary Kiln
Plasma Gas Arc Vitrification
Primary Alternatives
Sub-Alternatives
26 Source: Westinghouse
3. Dredging & Artificial Island
1. No Mitigation Techniques
2. Hydraulic Dredging
0
0.02
0.04
0.06
0.08
0.1
0.12
0.14
0.16
0.18
0.2
$0 $50 $100 $150 $200 $250 $300
Cost/Revenue PDF (Triangular)
Low Grade Tile
Revenue
Cost
0
0.02
0.04
0.06
0.08
0.1
0.12
0.14
0.16
0.18
0.2
$0 $50 $100 $150 $200 $250 $300
Cost/Revenue PDF (Triangular)
High Grade Tile
Revenue
Cost
Cost/Revenue ($ per cubic yard) Distribution (Triangular) Comparisons:
Plasma Gas Arc Vitrification
Quarry Low Temperature
Washing Rotary Kiln
Plasma Gas Arc Vitrification
Primary Alternatives
Sub-Alternatives
Agenda
• Context
• Stakeholders
• Problem/Need Statement
• Design Alternatives
• Analysis and Design of Simulation
• Design of Experiment
• Results, Analysis & Recommendations
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Project & Modeling Scope
Problem Overall:
Sediment build up at Conowingo Dam has been detrimental to the Chesapeake Bay’s ecosystem health following major storms (transient events)
Problem Addressed by Model:
1. Sediment removal
2. Associated cost of remediation due to deposition of sediment and nutrients to the Chesapeake Bay
3. Sediment processing , sediment product production
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Model Simulates Model Type
Sediment Removal Model
Sediment flow from upstream and sediment outflow at Conowingo Dam
- Microsoft Excel Spreadsheet
Ecological Impact Model
Cost of remediation and recovery based on phosphorus deposition to the Chesapeake Bay and hypothetical waste treatment upgrade costs
- Java - Microsoft Excel Spreadsheet
Reuse-Business Model
Sediment product production, cost and revenue generation
- Microsoft Excel Spreadsheet (Crystal Ball)
Sediment Management Model Decomposition
Stochastic Sediment Management Model
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Source: USGS
Stochastic Sediment Removal Model Input Flow Rate (1967 – 2013)
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DRY FUTURE - 400,000 cfs max: • Average Flow: 38,908 • Median Flow: 26,826 • Standard Deviation: 38,855 • Avg. days/yr. > 150kcfs: 7.4
SIMILAR FUTURE-700,000 cfs max: • Average Flow: 43,464 • Median Flow: 28,638 • Standard Deviation: 46,335 • Avg. days/yr. > 150kcfs: 13.3
WET FUTURE - 1,000,000 cfs max: • Average Flow: 43,975 • Median Flow: 30,685 • Standard Deviation: 46,570 • Avg. days/yr. > 150kcfs: 9.8
Historical Data: • Average Flow: 41,271 • Median Flow: 28,100 • Standard Deviation:
47,095 • Avg. days/yr. >
150kcfs: 12
Sediment Removal Model Three Different Future Worlds
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Conowingo Dam
Velocity Profile at 700,000 cfs. Source: U.S. Army Corps. Of Engineers
Reservoir Bathymetry Source: USGS
Scaled x10 Vertically
𝑊
𝐿
𝐷
𝑳 = Length 𝑾 = Width 𝑫 = Depth 𝑾 ∗ 𝑳 = Surface Area (SA) 𝑾 ∗ 𝑫 = Cross-Sectional Area (A) 𝑾 ∗ 𝑳 ∗ 𝑫 = Volume (V)
Actual Proportions
Sediment Removal Model Bathymetry and Gridding
1 mi.
Water flow
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𝑍 =𝑤𝑠
κ ∗110 (𝑣𝑖)
𝑄 =222196.84
𝑍
𝑆𝑆 = 0.000012(𝑄)1.88623
𝑆𝑆𝑖 = 1.2 × 10−5222196.84
𝑍𝑖
1.88623𝑆𝐴𝑖 𝑆𝐴𝑖
𝑖 = 1, . . , 400
𝐴𝑛+1,𝑖 = 𝐴𝑛,𝑖 −
4×106∗32.67
365
𝑉𝑖 𝑉𝑖400𝑖=1
𝐿𝑖+𝑆𝑆𝑖∗32.67
𝐿𝑖+
𝐷𝑆∗108
365
𝑆𝐴𝑖 𝑆𝐴𝑖200𝑖=1
𝐿𝑖
𝑖 = 1, . . , 400; 𝑛 = 1, . . , 7305
Initial Cross-Sectional Area
Area Decrease: Redeposition
Area Increase: Scoured Sediment
Daily Cross-Sectional Area
Daily Scoured Sediment
Rouse Number
Source: U.S. Corps. of Engineering
Variable Description
L Reservoir Length
W Reservoir Width
D Reservoir Depth
A Cross-Sectional Area
SA Surface Area
V Volume
Q Flow Rate
v Flow Rate Adjusted Velocity
SS Scoured Sediment
DS Dredged Sediment
Z Rouse Number
ws Particle Fall Velocity
k Von Kármán Constant
Sediment Removal Model Continuity & Shear Est. Equations
Area Increase: Dredged Sediment
Correlations: Flow, Rouse, Scoured Sediment
Sediment Removal Model Assumptions
• Flow rates follow same trend from past 46 years
• Seeded correlation distributions are lognormal
• Redeposition is a fixed rate (4,000,000 tons/yr.)
• Particle fall velocity is fixed throughout reservoir
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Average Daily Sediment Scoured (≤ 6,800 tons/day)
• Pdaily = Pavg(SS)
• 0.001320 ≤ Pavg ≤ 0.002933
Above Average Daily Sediment Scoured ( > 6,800 tons/day)
• Pdaily = Pmajor (SS)
• Pmajor = 0.0005578
SurrogateRemediation Expense (Waste Treatment Plant Renovations)
• 𝑹 = 𝑳𝑺𝑹𝑷𝑻𝑴𝑫𝑳 − 𝑷 𝑾𝒄𝒐𝒔𝒕
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Ecological Impact Model Equations
Pdaily – daily phosphorus in tons
SS– daily sediment scoured in tons
Pavg– random number that denotes average percent of phosphorus per ton of sediment
Pmajor– denotes percent of phosphorus per ton of sediment during major scouring
LSRPTMDL – Lower Susquehanna TMDL limit for phosphorus (1895 tons)
Wcost– average expense of phosphorus waste treatment renovations per TMDL limits
Ecological Impact Model Assumptions
• Linear correlation between sediment scoured and phosphorus scoured
• Linear correlation between hypothetical waste treatment upgrade costs and phosphorus scoured
• Nitrogen scoured is negligible with relation to waste treatment plant upgrade costs
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Average ANNUAL Pollution Loads
(tons)
Tropical Storm-Lee Related Pollution Loads (tons)
Phosphorus (Ps) 2,600-3,300 10,600
Sediment (Ss) 890,000-2,500,000 19,000,000
Ratio (Ps/Ss) 0.00132-0.0029 0.000558
Ecological Impact Model Surrogate Data
Based on surrogate data on Chesapeake Bay watershed wastewater treatment plant upgrades: Average expense of waste treatment renovations based on P TMDL :
Wcost = $ 6,300 /ton of phosphorus
% range of average ton of phosphorus per ton sediment
% of ton of phosphorus per ton sediment during major scouring
Waste Treatment
Plant Plant Name or Areas Served
Upgrade Costs
(millions)
Plant 1 Lexington and
Rockbridge County(VA) 15.2
Plant 2 Hopewell (VA) - 1997 50
Plant 3 Hopewell (VA) - Current 62
Plant 4 Buena Vista (VA) 30
Business Reuse Model Equations
Production Equation: 𝑹𝒊 ∗ 𝒂𝒊 = 𝒑𝒊
Net Cost Equation: 𝑻𝒊 = 𝒄𝒊 +𝑴𝒙 − 𝒓𝒆𝒗𝒊 ∗ 𝑹𝒊
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𝒂𝒊 = amount of sediment needed to make one unit of product i
Ri = amount of sediment removed and used for product i
p𝒊 = units of product i produced
rev𝒊 = revenue per cubic yard of product i
c𝒊 =cost to produce product I per cubic yard of sediment processed
Ti = total cost
Mx = mitigation cost for one cubic yard of sediment
Business Reuse Model Assumptions (20 year NPV)
• Sediment can be processed on time
• Cost/revenue distributions are the same for all amounts of sediment input
• Cost/revenue values all follow a triangular distribution across all alternatives
• Market values will stay the same (no inflation for cost and revenue)
• Time horizon (20 years) is not a variable
• Discount rate=5%
• One-time set up cost excluded (included in utility analysis)
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Agenda
• Context
• Stakeholders
• Problem/Need Statement
• Design Alternatives
• Analysis and Design of Simulation
• Design of Experiment
• Results, Analysis & Recommendations
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Inputs Outputs
Flow Rate
(per day)
Reservoir Bathymetry (per day)
Reservoir Velocity Profile
(per day)
Sediment Scoured (per day)
Sediment Redeposited (per year)
source: U.S. Corps. of Engineering
Sediment Dredged (per year)
(note: dredging evenly 5 miles upstream daily)
Reservoir Bathymetry (per day)
Scoured Sediment (per day)
No Mitigation
𝑸 𝑳𝒊,𝑾𝒊, 𝑫𝒊 𝒗𝒊 𝑺𝑺𝒊 4,000,000 tons 0 cy. 𝑳𝒊,𝑾𝒊, 𝑫𝒊 𝑺𝑺𝒊
Dredging 𝑸
𝑳𝒊,𝑾𝒊, 𝑫𝒊 𝒗𝒊 𝑺𝑺𝒊
4,000,000 tons
1,000,000 cy. 𝑳𝒊,𝑾𝒊, 𝑫𝒊 𝑺𝑺𝒊
𝑳𝒊,𝑾𝒊, 𝑫𝒊 𝒗𝒊 𝑺𝑺𝒊 3,000,000 cy. 𝑳𝒊,𝑾𝒊, 𝑫𝒊 𝑺𝑺𝒊
𝑳𝒊,𝑾𝒊, 𝑫𝒊 𝒗𝒊 𝑺𝑺𝒊 5,000,000 cy. 𝑳𝒊,𝑾𝒊, 𝑫𝒊 𝑺𝑺𝒊
Dredging & Island
(note: 2 years @ 5 million
cy./yr. dredged before
simulation start)
𝑸
𝑳𝒊,𝑾𝒊, 𝑫𝒊 𝒗𝒊 𝑺𝑺𝒊
4,000,000 tons
0 cy. 𝑳𝒊,𝑾𝒊, 𝑫𝒊 𝑺𝑺𝒊
𝑳𝒊,𝑾𝒊, 𝑫𝒊 𝒗𝒊 𝑺𝑺𝒊 1,000,000 cy. 𝑳𝒊,𝑾𝒊, 𝑫𝒊 𝑺𝑺𝒊
𝑳𝒊,𝑾𝒊, 𝑫𝒊 𝒗𝒊 𝑺𝑺𝒊 3,000,000 cy. 𝑳𝒊,𝑾𝒊, 𝑫𝒊 𝑺𝑺𝒊
𝑳𝒊,𝑾𝒊, 𝑫𝒊 𝒗𝒊 𝑺𝑺𝒊 5,000,000 cy. 𝑳𝒊,𝑾𝒊, 𝑫𝒊 𝑺𝑺𝒊
Inputs to Feedback
Sediment Removal Model – Design of Experiment For three future worlds (x3)
Ecological Impact Model - Design of Experiment
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Input Outputs
Scoured Sediment (per day)
Estimated Remediation Expense Scoured Phosphorus
(per year)
No Mitigation 𝑺𝑺 𝑹 𝑷
Dredging
𝑺𝑺 𝑹 𝑷
𝑺𝑺 𝑹 𝑷
𝑺𝑺 𝑹 𝑷
Dredging & Island
(note: 2 years @ 5 million cy./yr. dredged before simulation start)
𝑺𝑺 𝑹 𝑷
𝑺𝑺 𝑹 𝑷
𝑺𝑺 𝑹 𝑷
𝑺𝑺 𝑹 𝑷
For current world view (700,000 cfs max)
Business Reuse Model - Design of Experiment
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Product Alternative
Inputs Outputs
Sediment Dredged (per year)
(note: dredging evenly 5 miles upstream daily)
Dredging and Transportation Costs
Cost to produce product
Revenue Generated from product
Net cost to produce product
Amount of product produced
Lightweight Aggregate
1,000,000 cy.
𝑴𝒙 𝒄𝒊 𝒓𝒆𝒗𝒊
𝑻𝒊 𝒑𝒊
3,000,000 cy. 𝑻𝒊 𝒑𝒊
5,000,000 cy. 𝑻𝒊 𝒑𝒊
…
1,000,000 cy.
𝑴𝒙 𝒄𝒊 𝒓𝒆𝒗𝒊
𝑻𝒊 𝒑𝒊
3,000,000 cy. 𝑻𝒊 𝒑𝒊
5,000,000 cy. 𝑻𝒊 𝒑𝒊
Plasma (high-grade)
1,000,000 cy.
𝑴𝒙 𝒄𝒊 𝒓𝒆𝒗𝒊
𝑻𝒊 𝒑𝒊
3,000,000 cy. 𝑻𝒊 𝒑𝒊
5,000,000 cy. 𝑻𝒊 𝒑𝒊
Sediment Management System Value Hierarchy
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• 𝑼𝒊=Utility of dredging alternative i
• 𝑺𝒊=scour potential decrease percentage of dredging alternative i
• 𝑺𝟓=scour potential decrease percentage of dredging 5 million cy per year (the best option)
• 𝑬𝟎=normalized cost of remediation of no mitigation after a scouring event
• 𝑬𝒊=normalized cost of remediation of dredging alternative i after a scouring event
• 𝑬𝟓=normalized cost of remediation of dredging 5 million cy per year with artificial island(the best option)
Minimize Susquehanna
Sediment Impact to Chesapeake Bay
Sediment Scour Potential (0.5)
Ecological Impact (0.5)
𝑼𝒊 = 𝟎. 𝟓𝑺𝒊𝑺𝒎𝒂𝒙
+ 𝟎. 𝟓𝑬𝒎𝒊𝒏 − 𝑬𝒊𝑬𝒎𝒊𝒏 − 𝑬𝒎𝒂𝒙
,
𝒊 = 𝟏,…𝟖
Agenda
• Context
• Stakeholders
• Problem/Need Statement
• Design Alternatives
• Analysis and Design of Simulation
• Design of Experiment
• Results , Analysis & Recommendations
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Sediment Removal Model Results Future Looks Like Past - 700,000 cfs
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For every 1 million cy dredged: • 2% drop in scour (initial) • 0.41% decrease in scour (final with maximum dredging)
Sediment Removal Model Results Future Looks Like Past - 700,000 cfs
0%
5%
10%
15%
20%
25%
30%
35%
40%
45%
50%
no mitigation Island 1-million Island,1-million 3-million Island,3-million Island,5-million 5-million
Total Percent Decrease in Scour
Percent Decrease in Scour After 20 years (700,000 cfs. max)
49
$(4,000,000,000.00)
$(3,500,000,000.00)
$(3,000,000,000.00)
$(2,500,000,000.00)
$(2,000,000,000.00)
$(1,500,000,000.00)
$(1,000,000,000.00)
$(500,000,000.00)
$-
$500,000,000.00
$1,000,000,000.00
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
Ne
t P
rese
nt
Val
ue
Year
Plasma high-grade
$(4,000,000,000.00)
$(3,500,000,000.00)
$(3,000,000,000.00)
$(2,500,000,000.00)
$(2,000,000,000.00)
$(1,500,000,000.00)
$(1,000,000,000.00)
$(500,000,000.00)
$-
$500,000,000.00
$1,000,000,000.00
1 2 3 4 5 6 7 8 9 1011121314151617181920
Ne
t P
rese
nt
Val
ue
Year
Lightweight Aggregate
1 million cy/year
3 million cy/year
5 million cy/year
Business Reuse Model Results Marginal Cost Time Flow Comparison :Two Sub-Alternatives
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
-$1 $0 $1 $2 $3 $4
Uti
lity
Cost (Billions, Net Present Value, discount factor=5%)
Island, 5 million 5 million
Island, 3 million
3 million
Island, 1 million
1 million
Island
No mitigation
Plasma High-Grade Lightweight Aggregate Quarry
Utility vs. Cost
50
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
-$1 $0 $1 $2 $3 $4
Uti
lity
Cost (Billions, Net Present Value, discount factor=5%)
Island, 5 million 5 million
Island, 3 million
3 million
Island, 1 million
1 million
Island
No mitigation
Plasma High-Grade Lightweight Aggregate Quarry
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
-$1 $0 $1 $2 $3 $4
Uti
lity
Cost (Billions, Net Present Value, discount factor=5%)
Island, 5 million 5 million
Island, 3 million
3 million
Island, 1 million
1 million
Island
No mitigation
Plasma High-Grade Lightweight Aggregate Quarry
Utility vs. Cost
51
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
-$1 $0 $1 $2 $3 $4
Uti
lity
Cost (Billions, Net Present Value, discount factor=20%)
Plasma High-Grade Lightweight Aggregate Quarry
Island, 5 million 5 million
Island, 3 million
3 million
Island, 1 million
Recommendations
52
• Best Alternative: Dredge 5 million cy/year and process into high-grade arc. tile via plasma gas arc vitrification
• Contact specializing company to perform further analysis for Conowingo Reservoir
• Next Best Alternative after Plasma: Dredge 1 million cy/year and process into lightweight aggregate with construction of artificial island
Future Work
• Conduct additional cost benefit analysis with any additional cost data attained for ecosystem impact
• Look into dredging dams/reservoirs further North on the Susquehanna River
– Dispersion of cost
– Sediment reduction prior to entrance into Conowingo Reservoir
Rank Alternative
1 Plasma, 5 million
2 Plasma, 5 million with Island
3 Plasma, 3 million with Island
4 Plasma, 3 million
5 Lightweight Aggregate, 1 million with Island
Questions?
53