Design of a Dam Sediment
Management System to Aid Water
Quality Restoration of the
Chesapeake Bay
Presented By:
Kevin Cazenas
Rayhan Ain
Conowingo Dam
Sheri Gravette
Said Masoud
Sponsors:
Lower
Susquehanna
Riverkeeper
West & Rhode
Riverkeeper
Faculty Advisor:
George Donohue
Sediment
Plume from
Transient
Scouring
Agenda
• Context
• Stakeholders
• Problem/Need Statement
• Design Alternatives
• Analysis and Design of Simulation
• Design of Experiment
• Results, Analysis & Recommendations
2
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
Map of the Chesapeake Bay Watershed
Source: The PA Dept. of Environmental Protection
3
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
Map of Conowingo Reservoir
Source: US Army Corps of Engineers, (2013)
4
Lower Susquehanna River:
Steady State vs. Transient State
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
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
Chesapeake Bay: Before and After Tropical Storm Lee
Source: MODIS Rapid Response Team at NASA GSFC
5
Flow and Sediment Build-up in Conowingo Reservoir
• Rouse number defines a
concentration profile of
sediment
–
Determines how sediment will be
transported in flowing water
Holtwood Dam
• Rouse Number:
𝝎𝒔
𝒁=
𝒖∗
𝝎𝒔 =Sediment fall velocity
𝒖∗ =shear velocity
• Significant amount of
suspended sediment is
located directly behind the
dam (areas away from
turbines)
Conowingo Dam
Rouse Number for Medium Silt Particle at 30,000 cfs
Source: S. Scott (2012)
6
Sediment Deposition at Conowingo Dam
100%
Sediment Deposition
Expected
Threshold
90%
80%
150
70%
60%
50%
100
40%
Percent Capacity
Sediment Deposition (million tons)
200
30%
50
20%
10%
0
0%
1929
1936
1943
1950
1957
1964
1971
1978
1985
1992
1999
2006
2013
2020
2027
• 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, steadystate flow
Year
Sediment Deposition in Conowingo Reservoir; Construction to 2008 with Gap Prediction
Source of Data: Hirsch, R.M., (2012)
7
Chesapeake Bay Total Maximum Daily Load
(TMDL)
• 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
8
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)
9
Agenda
• Context
• Stakeholders
• Problem/Need Statement
• Design Alternatives
• Analysis and Design of Simulation
• Design of Experiment
• Results, Analysis & Recommendations
10
Primary Stakeholders
Objective(s)
Lower Susquehanna
Riverkeeper and Stewards of
the Lower Susquehanna, Inc.
(SOLs)
-
Chesapeake WaterkeepersWest & Rhode Riverkeeper
Issue(s)
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
-
-
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
-
-
-
-
-
-
Cost to remove sediment from Reservoir is
high
Providing pressure on FERC to require more
strict relicensing requirements for Conowingo
Dam Hydropower Plant
11
Agenda
• Context
• Stakeholders
• Problem/Need Statement
• Design Alternatives
• Analysis and Design of Simulation
• Design of Experiment
• Results, Analysis & Recommendations
12
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
13
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
14
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.
15
Agenda
• Context
• Stakeholders
• Problem/Need Statement
• Design Alternatives
• Analysis and Design of Simulation
• Design of Experiment
• Results, Analysis & Recommendations
16
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
Conowingo Dam
Source: D. DeKok (2008)
17
1. No Mitigation
Techniques
2. Hydraulic
Dredging
3. Dredging &
Artificial Island
WHAT
HOW
• Sediment will reach capacity
by 2030
• Normal Flow: < 30,000 cfs
• Major scouring events will
have the largest impact
Normal Flow at Conowingo Dam
Source: E. Malumuth (2012)
• Major Scouring Event: > 300,000 cfs
18
1. No Mitigation
Techniques
2. Hydraulic
Dredging
3. Dredging &
Artificial Island
WHAT
HOW
• Remove sediment mechanically
• Rotating cutter to agitate & stir up
• Concentration on suspended
sediment
• Pipeline pumps sediment to surface
• Product yield from sediment
• Collection for further treatment
Hydraulic Dredging Process
Source: C. Johnson
19
1. No Mitigation
Techniques
2. Hydraulic
Dredging
3. Dredging &
Artificial Island
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)
20
Primary Alternatives
1. No Mitigation
Techniques
2. Hydraulic
Dredging
3. Dredging &
Artificial Island
Quarry
Low Temperature
Washing
Sub-Alternatives
Rotary Kiln
Plasma Gas Arc
Vitrification
Quarry
• Direct transportation from reservoir
to quarry
• No opportunity to offset cost
• No one-time investment cost
Rock Quarry
21
Primary Alternatives
1. No Mitigation
Techniques
2. Hydraulic
Dredging
3. Dredging &
Artificial Island
Quarry
Low Temperature
Washing
Sub-Alternatives
Rotary Kiln
Plasma Gas Arc
Vitrification
Low-Temperature Sediment
Washing
• Process includes:
• Non-thermal Decontamination
– Loose screening
– Dewatering
• Potential use as manufactured
– Aeration
topsoil
– Sediment washing/remediation
• One-time cost: Approx. $25
– Oxidation and cavitation
million (BioGenesis)
Low Temperature Washing Facility
Manufactured Topsoil
22
Primary Alternatives
1. No Mitigation
Techniques
2. Hydraulic
Dredging
3. Dredging &
Artificial Island
Quarry
Low Temperature
Washing
Sub-Alternatives
Rotary Kiln
Plasma Gas Arc
Vitrification
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)
Rotary Kiln Operation
23
1. No Mitigation
Techniques
2. Hydraulic
Dredging
3. Dredging &
Artificial Island
Quarry
Low Temperature
Washing
Primary Alternatives
Sub-Alternatives
Sub-Alternatives
Rotary Kiln
Plasma Gas Arc
Vitrification
Plasma Gas Arc Vitrification (Glass Aggregate)
• 99.99 % Decontamination and incineration
of all organic compounds
• Intense thermal decontamination process
• Output: vitrified glassed compound “slag”
• One-time cost: Approx. $430 million
(Westinghouse Plasma)
Glass Aggregate (Slag)
24
Primary Alternatives
1. No Mitigation
Techniques
2. Hydraulic
Dredging
3. Dredging &
Artificial Island
Quarry
Low Temperature
Washing
Sub-Alternatives
Plasma Gas Arc
Vitrification
Rotary Kiln
Cost/Revenue ($ per cubic yard) Distribution (Triangular)
Comparisons:
Quarry, Topsoil, and Lightweight Aggregate
Cost PDF (Triangular)
Quarry
0.2
0.18
0.16
0.14
0.12
0.1
0.08
0.06
0.04
0.02
0
$100
Lightweight Aggregate
Topsoil
0.2
0.18
0.16
0.14
0.12
0.1
0.08
0.06
0.04
0.02
0
$0
Cost/Revenue PDF (Triangular)
Cost/Revenue PDF (Triangular)
$200
$300
0.2
0.18
0.16
0.14
0.12
0.1
0.08
0.06
0.04
0.02
0
Revenue
Cost
$0
$50
$100
$150
$200
$250
$300
$0
$50
$100
$150
$200
Sources: LSRWA (Quarry); M. Lawler et al and D. Pettinelli (Topsoil); JCI/Upcycle Associates, LLC (LWA)
25
$250
$300
Primary Alternatives
1. No Mitigation
Techniques
2. Hydraulic
Dredging
3. Dredging &
Artificial Island
Quarry
Low Temperature
Washing
Sub-Alternatives
Plasma Gas Arc
Vitrification
Rotary Kiln
Cost/Revenue ($ per cubic yard) Distribution (Triangular)
Comparisons:
Plasma Gas Arc Vitrification
Cost/Revenue PDF (Triangular)
Cost/Revenue PDF (Triangular)
High Grade Tile
Low Grade Tile
0.2
0.2
0.18
0.18
0.16
0.16
0.14
0.14
0.12
0.12
Revenue
Cost
0.1
0.08
0.06
Revenue
0.1
0.08
Cost
0.06
0.04
0.04
0.02
0.02
0
0
$0
$50
$100
$150
$200
$250
$300
$0
Source: Westinghouse
$50
$100
$150
$200
$250
$300
26
Agenda
• Context
• Stakeholders
• Problem/Need Statement
• Design Alternatives
• Analysis and Design of Simulation
• Design of Experiment
• Results, Analysis & Recommendations
27
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
28
Sediment Management Model Decomposition
Model
Sediment Removal Model
Ecological Impact Model
Reuse-Business Model
Simulates
Model Type
Sediment flow from upstream
and sediment outflow at
Conowingo Dam
- Microsoft Excel Spreadsheet
Cost of remediation and
- Java
recovery based on phosphorus - Microsoft Excel Spreadsheet
deposition to the Chesapeake
Bay and hypothetical waste
treatment upgrade costs
Sediment product production,
cost and revenue generation
- Microsoft Excel Spreadsheet
(Crystal Ball)
29
Stochastic Sediment Management Model
30
Stochastic Sediment Removal Model Input
Flow Rate (1967 – 2013)
Source: USGS
31
Sediment Removal Model
Three Different Future Worlds
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
Historical Data:
• Average Flow: 41,271
• Median Flow: 28,100
• Standard Deviation:
47,095
• Avg. days/yr. >
150kcfs: 12
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
32
Sediment Removal Model
Bathymetry and Gridding
1 mi.
𝑳 = Length
𝑾 = Width
𝑫 = Depth
𝑾 ∗ 𝑳 = Surface Area (SA)
𝑾 ∗ 𝑫 = Cross-Sectional Area (A)
𝑾 ∗ 𝑳 ∗ 𝑫 = Volume (V)
𝑊
Water
flow
Scaled x10 Vertically
𝐿
𝐷
Conowingo Dam
Actual Proportions
Velocity Profile at 700,000 cfs.
Source: U.S. Army Corps. Of Engineers
Reservoir Bathymetry
Source: USGS
33
Sediment Removal Model
Daily Cross-Sectional Area
Continuity & Shear Est. Equations
4×106 ∗32.67
365
𝐴𝑛+1,𝑖 = 𝐴𝑛,𝑖 −
Initial CrossSectional Area
𝑉𝑖
400 𝑉
𝑖=1 𝑖
+
𝐿𝑖
Area Decrease:
Redeposition
𝑖 = 1, . . , 400;
𝑆𝑆𝑖 ∗32.67
𝐿𝑖
𝑛 = 1, . . , 7305
+
Description
Reservoir Length
W
Reservoir Width
D
Reservoir Depth
A
Cross-Sectional Area
SA
Surface Area
V
Volume
Correlations: Flow, Rouse, Scoured Sediment
Q
Flow Rate
222196.84
𝑄=
𝑍
v
Flow Rate Adjusted Velocity
SS
Scoured Sediment
DS
Dredged Sediment
Z
Rouse Number
ws
Particle Fall Velocity
k
Von Kármán Constant
222196.84
𝑍𝑖
1.88623
𝑆𝐴𝑖
𝑆𝐴𝑖
𝑖 = 1, . . , 400
𝑤𝑠
𝑍=
1
κ ∗ 10 (𝑣𝑖 )
Area Increase:
Dredged Sediment
L
𝑆𝑆𝑖 = 1.2 × 10−5
Rouse Number
𝐿𝑖
Area Increase:
Scoured Sediment
Variable
Daily Scoured Sediment
𝑆𝐴𝑖
200 𝑆𝐴
𝑖
𝑖=1
𝐷𝑆∗108
365
𝑆𝑆 = 0.000012(𝑄)1.88623
Source: U.S. Corps. of Engineering
34
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
35
Ecological Impact Model
Equations
Average Daily Sediment Scoured
(≤ 6,800 tons/day)
Pdaily – daily phosphorus in tons
• Pdaily = Pavg(SS)
SS– daily sediment scoured in tons
• 0.001320 ≤ Pavg ≤ 0.002933
Pavg– random number that denotes
average percent of phosphorus per ton
of sediment
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
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
36
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
37
Ecological Impact Model
Surrogate Data
Average ANNUAL
Pollution Loads
(tons)
Phosphorus (Ps)
Sediment (Ss)
Ratio (Ps/Ss)
Tropical Storm-Lee
Related Pollution
Loads (tons)
2,600-3,300
10,600
890,000-2,500,000
19,000,000
0.00132-0.0029
0.000558
% range of average ton of
phosphorus per ton sediment
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
Waste
Treatment
Plant
Upgrade
Costs
(millions)
Plant 1
Plant Name or
Areas Served
Lexington and
Rockbridge County(VA)
Plant 2
Hopewell (VA) - 1997
50
Plant 3
Hopewell (VA) - Current
62
Plant 4
Buena Vista (VA)
30
% of ton of
phosphorus per ton
sediment during
major scouring
15.2
38
Business Reuse Model
Equations
Production Equation:
𝑹𝒊 ∗ 𝒂𝒊 = 𝒑𝒊
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
Net Cost Equation:
𝑻𝒊 = 𝒄𝒊 + 𝑴𝒙 − 𝒓𝒆𝒗𝒊 ∗ 𝑹𝒊
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
39
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)
40
Agenda
• Context
• Stakeholders
• Problem/Need Statement
• Design Alternatives
• Analysis and Design of Simulation
• Design of Experiment
• Results, Analysis & Recommendations
41
Sediment Removal Model – Design of Experiment
For three future worlds (x3)
Inputs
No
Mitigation
Dredging
Flow
Rate
(per day)
Reservoir
Bathymetry
(per day)
Reservoir
Velocity
Profile
(per day)
𝑸
𝑳𝒊 , 𝑾𝒊 , 𝑫𝒊
𝒗𝒊
𝑺𝑺𝒊
𝑳𝒊 , 𝑾𝒊 , 𝑫𝒊
𝒗𝒊
𝑺𝑺𝒊
𝑳𝒊 , 𝑾𝒊 , 𝑫𝒊
𝒗𝒊
𝑺𝑺𝒊
𝑳𝒊 , 𝑾𝒊 , 𝑫𝒊
𝒗𝒊
𝑳𝒊 , 𝑾𝒊 , 𝑫𝒊
𝑸
Dredging &
Island
(note: 2 years
@ 5 million
cy./yr. dredged
before
simulation start)
𝑸
Sediment
Scoured
(per day)
Outputs
Sediment
Redeposited
(per year)
Sediment
Dredged
(per year)
Reservoir
Bathymetry
(per day)
Scoured
Sediment
(per day)
source: U.S. Corps.
of Engineering
(note: dredging
evenly 5 miles
upstream daily)
4,000,000 tons
0 cy.
𝑳𝒊 , 𝑾𝒊 , 𝑫𝒊
𝑺𝑺𝒊
1,000,000 cy.
𝑳𝒊 , 𝑾𝒊 , 𝑫𝒊
𝑺𝑺𝒊
3,000,000 cy.
𝑳𝒊 , 𝑾𝒊 , 𝑫𝒊
𝑺𝑺𝒊
𝑺𝑺𝒊
5,000,000 cy.
𝑳𝒊 , 𝑾𝒊 , 𝑫𝒊
𝑺𝑺𝒊
𝒗𝒊
𝑺𝑺𝒊
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
4,000,000 tons
4,000,000 tons
Inputs to Feedback
42
Ecological Impact Model - Design of Experiment
For current world view (700,000 cfs max)
Input
No Mitigation
Dredging
Dredging &
Island
(note: 2 years @ 5
million cy./yr.
dredged before
simulation start)
Outputs
Scoured Sediment
(per day)
Estimated Remediation Expense
Scoured Phosphorus
(per year)
𝑺𝑺
𝑹
𝑷
𝑺𝑺
𝑹
𝑷
𝑺𝑺
𝑹
𝑷
𝑺𝑺
𝑹
𝑷
𝑺𝑺
𝑹
𝑷
𝑺𝑺
𝑹
𝑷
𝑺𝑺
𝑹
𝑷
𝑺𝑺
𝑹
𝑷
43
Business Reuse Model - Design of Experiment
Inputs
Product
Alternative
Sediment Dredged
(per year)
(note: dredging evenly
5 miles upstream daily)
Outputs
Net cost to
produce
product
Amount
of
product
produce
d
𝑻𝒊
𝒑𝒊
𝑻𝒊
𝒑𝒊
5,000,000 cy.
𝑻𝒊
𝒑𝒊
1,000,000 cy.
𝑻𝒊
𝒑𝒊
𝑻𝒊
𝒑𝒊
5,000,000 cy.
𝑻𝒊
𝒑𝒊
1,000,000 cy.
𝑻𝒊
𝒑𝒊
𝑻𝒊
𝒑𝒊
𝑻𝒊
𝒑𝒊
Dredging and
Cost to
Transportation produce
Costs
product
Revenue
Generated
from product
1,000,000 cy.
Lightweight
Aggregate
…
Plasma (highgrade)
3,000,000 cy.
3,000,000 cy.
3,000,000 cy.
5,000,000 cy.
𝑴𝒙
𝑴𝒙
𝑴𝒙
𝒄𝒊
𝒄𝒊
𝒄𝒊
𝒓𝒆𝒗𝒊
𝒓𝒆𝒗𝒊
𝒓𝒆𝒗𝒊
44
Sediment Management System
Value Hierarchy
Minimize
Susquehanna
Sediment Impact
to Chesapeake Bay
Sediment Scour
Potential (0.5)
Ecological Impact
(0.5)
𝑺𝒊
𝑬𝒎𝒊𝒏 − 𝑬𝒊
𝑼𝒊 = 𝟎. 𝟓
+ 𝟎. 𝟓
,
𝑺𝒎𝒂𝒙
𝑬𝒎𝒊𝒏 − 𝑬𝒎𝒂𝒙
𝒊 = 𝟏, … 𝟖
• 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)
45
Agenda
• Context
• Stakeholders
• Problem/Need Statement
• Design Alternatives
• Analysis and Design of Simulation
• Design of Experiment
• Results , Analysis & Recommendations
46
Sediment Removal Model Results
Future Looks Like Past - 700,000 cfs
47
Sediment Removal Model Results
Future Looks Like Past - 700,000 cfs
Percent Decrease in Scour After 20 years (700,000 cfs. max)
Total Percent Decrease in Scour
50%
45%
40%
35%
30%
25%
20%
15%
10%
5%
0%
no mitigation
Island
1-million
Island,1-million
3-million
Island,3-million Island,5-million
For every 1 million cy dredged:
• 2% drop in scour (initial)
• 0.41% decrease in scour (final with maximum dredging)
5-million
48
Business Reuse Model Results
Marginal Cost Time Flow Comparison :Two Sub-Alternatives
$1,000,000,000.00
$1,000,000,000.00
$500,000,000.00
Plasma high-grade
$500,000,000.00
$-
$-
$(500,000,000.00)
Net Present Value
$(500,000,000.00)
Net Present Value
Lightweight Aggregate
$(1,000,000,000.00)
$(1,500,000,000.00)
$(2,000,000,000.00)
$(1,000,000,000.00)
3 million cy/year
$(2,000,000,000.00)
$(2,500,000,000.00)
$(2,500,000,000.00)
$(3,000,000,000.00)
$(3,000,000,000.00)
$(3,500,000,000.00)
$(3,500,000,000.00)
$(4,000,000,000.00)
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
Year
1 million cy/year
$(1,500,000,000.00)
5 million cy/year
$(4,000,000,000.00)
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
Year
49
Utility vs. Cost
Island, 5 million
5 million
Island, 3 million
3 million
Island, 1 million
1
0.9
0.8
0.7
Plasma HighGrade
Utility
0.6
1 million
Lightweight
Aggregate
0.5
Quarry
0.4
Island
0.3
0.2
0.1
No mitigation
0
-$1
$0
$1
$2
$3
$4
Cost (Billions, Net Present Value, discount factor=5%)
50
Utility vs. Cost
Island, 5 million
5 million
Island, 3 million
3 million
Island, 1 million
1
0.9
0.8
0.7
Plasma HighGrade
Utility
0.6
Lightweight
Aggregate
0.5
Quarry
0.4
0.3
0.2
0.1
0
-$1
$0
$1
$2
$3
$4
Cost (Billions, Net Present Value, discount factor=20%)
51
Recommendations
• 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
52
Questions?
53