Design of a Dam Management System to Aid Water Quality Restoration of the Chesapeake Bay Presented By: Sheri Gravette Kevin Cazenas Said Masoud Rayhan Ain Sediment Plume from Transient

Scouring

Sponsors: Lower West & Rhode Susquehanna Riverkeeper Riverkeeper Dam Conowingo

Faculty Advisor: George Donohue

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

• 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 Transient state: river flow rate higher less than 30,000 cfs than 300,000 cfs – Sediment/nutrients enters Chesapeake Bay at low-moderate rate – Major Scouring event: enhanced of – TMDL regulations are related to steady sediment due to: state – 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 Holtwood Dam transported in flowing water • Rouse Number: 흎 풁 = 풔 풖∗

흎풔=Sediment fall velocity 풖∗=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 6 Source: S. Scott (2012) Sediment Deposition at Conowingo Dam

100% 200 Sediment Deposition • Deposition potential –

Expected 90%

) Threshold expected sediment 80% deposited over a given 150 70% time

(million tons (million 60% 100 50% • At maximum capacity all

40% Susquehanna River Percent Capacity Percent 30% sediment flow s through 50

20% to the Chesapeake Bay Sediment Deposition Deposition Sediment 10% during normal, steady-

0 0% state flow 1929 1936 1943 1950 1957 1964 1971 1978 1985 1992 1999 2006 2013 2020 2027 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) Issue(s) Lower Susquehanna - Find alternative uses for the sediment stored - Cost to remove sediment from Reservoir is Riverkeeper and Stewards of behind Conowingo Dam high the Lower Susquehanna, Inc. - Highlight vulnerabilities in environmental law - Providing pressure on FERC to require more (SOLs) - Minimize effects of major scouring events to strict relicensing requirements for Conowingo the Chesapeake Bay Dam Hydropower Plant

Chesapeake Waterkeepers- - Protect and improve the health of the - Cost to remove sediment from Reservoir is West & Rhode Riverkeeper Chesapeake Bay and waterways in the region high

Maryland and Pennsylvania - Maintain healthy waters for fishing and - Cost to remove sediment from Reservoir is Residents (Lower recreation high Susquehanna Watershed) - Improve water quality of the watershed - Value low cost for power production and - Receive allocated power from Hydroelectric better water quality Dam Exelon Generation – owner of - Obtain relicensing of Conowingo Dam prior to - Sediment build up has no impact on energy Conowingo Dam its expiration in September 2014 production - Maintain profit

Federal Energy Regulatory - Aid consumers in obtaining reliable, efficient - Pressure to update dam regulations Commission (FERC) and sustainable energy services - Define regulations for energy providers

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 2. Hydraulic 3. Dredging & Techniques Dredging Artificial Island

WHAT HOW • Sediment will reach capacity • Normal Flow: < 30,000 cfs by 2030 • Major Scouring Event: > 300,000 cfs • Major scouring events will have the largest impact

Normal Flow at Conowingo Dam Source: E. Malumuth (2012) 18 1. No Mitigation 2. Hydraulic 3. Dredging & Techniques 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 2. Hydraulic 3. Dredging & Techniques 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 Sub-Alternatives 1. No Mitigation 2. Hydraulic 3. Dredging & Techniques Dredging Artificial Island

Low Temperature Plasma Gas Arc Quarry Rotary Kiln Washing Vitrification

Quarry • Direct transportation from reservoir to quarry • No opportunity to offset cost • No one-time investment cost

Rock Quarry

21 Primary Alternatives Sub-Alternatives 1. No Mitigation 2. Hydraulic 3. Dredging & Techniques Dredging Artificial Island

Low Temperature Plasma Gas Arc Quarry Rotary Kiln Washing Vitrification Low-Temperature Sediment Washing • Process includes: • Non-thermal Decontamination – Loose screening • Potential use as manufactured – Dewatering topsoil – Aeration • One-time cost: Approx. $25 – Sediment washing/remediation million (BioGenesis) – Oxidation and

Low Temperature Washing Facility Manufactured Topsoil 22 Primary Alternatives Sub-Alternatives 1. No Mitigation 2. Hydraulic 3. Dredging & Techniques Dredging Artificial Island

Low Temperature Plasma Gas Arc Quarry Rotary Kiln Washing 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 Primary Alternatives Sub-Alternatives Sub-Alternatives 1. No Mitigation 2. Hydraulic 3. Dredging & Techniques Dredging Artificial Island

Low Temperature Plasma Gas Arc Quarry Rotary Kiln Washing 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 Sub-Alternatives 1. No Mitigation 2. Hydraulic 3. Dredging & Techniques Dredging Artificial Island

Low Temperature Plasma Gas Arc Quarry Rotary Kiln Washing Vitrification

Cost/Revenue ($ per cubic yard) Distribution (Triangular) Comparisons: Quarry, Topsoil, and Lightweight Aggregate

Cost PDF (Triangular) Cost/Revenue PDF (Triangular) Cost/Revenue PDF (Triangular) Quarry Topsoil Lightweight Aggregate 0.2 0.2 0.2 0.18 0.18 0.18 0.16 0.16 0.16 0.14 0.14 0.14 0.12 0.12 Revenue 0.12 0.1 0.1 0.1 0.08 0.08 Cost 0.08 0.06 0.06 0.06 0.04 0.04 0.04 0.02 0.02 0.02 0 0 0 $0 $100 $200 $300 $0 $50 $100 $150 $200 $250 $300 $0 $50 $100 $150 $200 $250 $300

Sources: LSRWA (Quarry); M. Lawler et al and D. Pettinelli (Topsoil); JCI/Upcycle Associates, LLC (LWA)

25 Primary Alternatives Sub-Alternatives 1. No Mitigation 2. Hydraulic 3. Dredging & Techniques Dredging Artificial Island

Low Temperature Plasma Gas Arc Quarry Rotary Kiln Washing Vitrification

Cost/Revenue ($ per cubic yard) Distribution (Triangular) Comparisons: Plasma Gas Arc Vitrification

Cost/Revenue PDF (Triangular) Cost/Revenue PDF (Triangular) Low Grade Tile High Grade Tile 0.2 0.2 0.18 0.18 0.16 0.16 0.14 0.14 0.12 0.12 0.1 Revenue 0.1 Revenue 0.08 Cost 0.08 Cost 0.06 0.06 0.04 0.04 0.02 0.02 0 0 $0 $50 $100 $150 $200 $250 $300 $0 $50 $100 $150 $200 $250 $300 Source: Westinghouse 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 Simulates Model Type

Sediment flow from upstream - Microsoft Excel Spreadsheet and sediment outflow at Sediment Removal Model Conowingo Dam

Cost of remediation and - Java recovery based on phosphorus - Microsoft Excel Spreadsheet deposition to the Chesapeake Ecological Impact Model Bay and hypothetical waste treatment upgrade costs

Sediment product production, - Microsoft Excel Spreadsheet cost and revenue generation (Crystal Ball) Reuse-Business Model

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: Historical Data: • Average Flow: 43,464 • Average Flow: 41,271 • Median Flow: 28,638 • Median Flow: 28,100 • Standard Deviation: 46,335 • Standard Deviation: • Avg. days/yr. > 150kcfs: 13.3 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. 푳 = Length 푾 = Width 푫 = Depth 푾 ∗ 푳 = Surface Area (SA) 푾 ∗ 푫 = Cross-Sectional Area (A) 푾 ∗ 푳 ∗ 푫 = Volume (V)

푊 Water Scaled x10 Vertically 퐿 flow

퐷

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 Continuity & Shear Est. Equations Daily Cross-Sectional Area 6 4×10 ∗32.67 푉푖 퐷푆∗108 푆퐴푖 365 400 365 200 푖=1 푉푖 푆푆푖∗32.67 푖=1 푆퐴푖 퐴푛+1,푖 = 퐴푛,푖 − + + 퐿푖 퐿푖 퐿푖

Initial Cross- Area Decrease: Area Increase: Area Increase: Sectional Area Redeposition 푖 = 1, . . , 400; 푛 = 1, . . , 7305 Scoured Sediment Dredged Sediment

Variable Description Daily Scoured Sediment L Reservoir Length 1.88623 W Reservoir Width 222196.84 푆퐴 −5 푖 D Reservoir Depth 푆푆푖 = 1.2 × 10 푍푖 푆퐴푖 A Cross-Sectional Area SA Surface Area 푖 = 1, . . , 400 V Volume Rouse Number Correlations: Flow, Rouse, Scoured Sediment Q Flow Rate 푤푠 222196.84 v Flow Rate Adjusted Velocity 푍 = 푄 = 1 푍 SS Scoured Sediment κ ∗ (푣푖) 10 DS Dredged Sediment

Z Rouse Number

w Particle Fall Velocity 푆푆 = 0.000012(푄)1.88623 s k Von Kármán Constant 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) Pmajor– denotes percent of phosphorus • Pdaily = Pmajor (SS) per ton of sediment during major scouring • Pmajor = 0.0005578 LSRPTMDL – Lower Susquehanna TMDL limit for phosphorus (1895 tons) SurrogateRemediation Expense (Waste Treatment Plant Renovations) Wcost– average expense of phosphorus waste treatment renovations per TMDL • 푹 = 푳푺푹푷 − 푷 푾 푻푴푫푳 풄풐풔풕 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 Based on surrogate data on Chesapeake Bay watershed wastewater treatment plant Average ANNUAL upgrades: Average expense of waste Tropical Storm-Lee Pollution Loads Related Pollution treatment renovations based on P TMDL : (tons) Loads (tons) W = $ 6,300 /ton of phosphorus cost Waste Upgrade Phosphorus (Ps) 2,600-3,300 10,600 Treatment Plant Name or Costs Plant Areas Served (millions) Sediment (S ) 890,000-2,500,000 19,000,000 Lexington and s Plant 1 Rockbridge County(VA) 15.2 Plant 2 Hopewell (VA) - 1997 50 Plant 3 Hopewell (VA) - Current 62 Ratio (Ps/Ss) 0.00132-0.0029 0.000558 Plant 4 Buena Vista (VA) 30

% range of average ton of % of ton of phosphorus per ton sediment phosphorus per ton sediment during major scouring 38 Business Reuse Model Equations

풂풊 = amount of sediment needed to make one unit of Production Equation: product i 푹풊 ∗ 풂풊 = 풑풊 Ri = amount of sediment removed and used for product i

p풊 = units of product i produced = Net Cost Equation: rev풊 revenue per cubic yard of product i c =cost to produce product I per cubic yard of sediment 푻 = 풄 + 푴 − 풓풆풗 ∗ 푹 풊 풊 풊 풙 풊 풊 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 Outputs

Sediment Reservoir Sediment Flow Reservoir Sediment Dredged Reservoir Scoured Velocity Redeposited Rate Bathymetry Scoured (per year) (per year) Bathymetry Sediment Profile (note: dredging (per day) (per day) (per day) source: U.S. Corps. (per day) (per day) evenly 5 miles (per day) of Engineering upstream daily) No 푸 푳 , 푾 , 푫 풗 푺푺 4,000,000 tons 0 cy. 푳 , 푾 , 푫 푺푺 Mitigation 풊 풊 풊 풊 풊 풊 풊 풊 풊

푳풊, 푾풊, 푫풊 풗풊 푺푺풊 1,000,000 cy. 푳풊, 푾풊, 푫풊 푺푺풊

Dredging 푸 푳풊, 푾풊, 푫풊 풗풊 푺푺풊 4,000,000 tons 3,000,000 cy. 푳풊, 푾풊, 푫풊 푺푺풊

푳풊, 푾풊, 푫풊 풗풊 푺푺풊 5,000,000 cy. 푳풊, 푾풊, 푫풊 푺푺풊

푳풊, 푾풊, 푫풊 풗풊 푺푺풊 0 cy. 푳풊, 푾풊, 푫풊 푺푺풊 Dredging & Island 푳풊, 푾풊, 푫풊 풗풊 푺푺풊 1,000,000 cy. 푳풊, 푾풊, 푫풊 푺푺풊 (note: 2 years @ 5 million 푸 4,000,000 tons cy./yr. dredged 푳풊, 푾풊, 푫풊 풗풊 푺푺풊 3,000,000 cy. 푳풊, 푾풊, 푫풊 푺푺풊 before simulation start) 푳풊, 푾풊, 푫풊 풗풊 푺푺풊 5,000,000 cy. 푳풊, 푾풊, 푫풊 푺푺풊

Inputs to Feedback 42 Ecological Impact Model - Design of Experiment For current world view (700,000 cfs max)

Input Outputs

Scoured Sediment Scoured Phosphorus Estimated Remediation Expense (per day) (per year)

No Mitigation 푺푺 푹 푷

푺푺 푹 푷

Dredging 푺푺 푹 푷

푺푺 푹 푷

푺푺 푹 푷 Dredging & Island 푺푺 푹 푷 (note: 2 years @ 5 million cy./yr. dredged before 푺푺 푹 푷 simulation start) 푺푺 푹 푷

43 Business Reuse Model - Design of Experiment

Inputs Outputs

Sediment Dredged Amount Product (per year) Dredging and Cost to Revenue Net cost to of Alternative (note: dredging evenly Transportation produce Generated produce product 5 miles upstream daily) Costs product from product product produce d

1,000,000 cy. 푻풊 풑풊 Lightweight 3,000,000 cy. Aggregate 푴풙 풄풊 풓풆풗풊 푻풊 풑풊

5,000,000 cy. 푻풊 풑풊

1,000,000 cy. 푻풊 풑풊

… 3,000,000 cy. 푴풙 풄풊 풓풆풗풊 푻풊 풑풊

5,000,000 cy. 푻풊 풑풊

1,000,000 cy. 푻풊 풑풊 Plasma (high- 3,000,000 cy. grade) 푴풙 풄풊 풓풆풗풊 푻풊 풑풊

5,000,000 cy. 푻풊 풑풊

44 Sediment Management System Value Hierarchy

Minimize Susquehanna • 푼풊=Utility of dredging alternative i Sediment Impact to Chesapeake Bay • 푺풊=scour potential decrease percentage of dredging alternative i

• 푺ퟓ=scour potential decrease percentage of dredging 5 million cy per year (the best Sediment Scour Ecological Impact option) Potential (0.5) (0.5) • 푬ퟎ=normalized cost of remediation of no mitigation after a scouring event

푺풊 푬풎풊풏 − 푬풊 • 푬풊=normalized cost of remediation of dredging 푼풊 = ퟎ. ퟓ + ퟎ. ퟓ , alternative i after a scouring event 푺풎풂풙 푬풎풊풏 − 푬풎풂풙 • 푬ퟓ=normalized cost of remediation of 풊 = ퟏ, … ퟖ 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) 50%

45%

40%

35%

30%

25%

20%

15%

10%

Total Percent Decrease in Scour in Decrease Percent Total 5%

0% no mitigation Island 1-million Island,1-million 3-million Island,3-million Island,5-million 5-million

For every 1 million cy dredged: • 2% drop in scour (initial) • 0.41% decrease in scour (final with maximum dredging) 48

Business Reuse Model Results Marginal Cost Time Flow Comparison :Two Sub-Alternatives

$1,000,000,000.00 $1,000,000,000.00 Lightweight Aggregate Plasma high-grade $500,000,000.00 $500,000,000.00

$- $-

$(500,000,000.00)

$(500,000,000.00)

$(1,000,000,000.00) $(1,000,000,000.00)

$(1,500,000,000.00) $(1,500,000,000.00) 1 million cy/year 3 million cy/year

$(2,000,000,000.00) Net PresentValue $(2,000,000,000.00) 5 million cy/year Net PresentValue

$(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) $(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 1 2 3 4 5 6 7 8 9 1011121314151617181920 Year Year

49 Utility vs. Cost

Island, 5 million 1 5 million Island, 3 million 0.9 3 million 0.8

0.7 Island, 1 million Plasma High- Grade

0.6

Lightweight 1 million Aggregate 0.5

Quarry

UtilityUtilityUtility 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 1 5 million Island, 3 million 0.9 3 million 0.8

Island, 1 million 0.7 Plasma High- Grade 0.6

Lightweight 0.5 Aggregate

Utility 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 Rank Alternative • Best Alternative: Dredge 5 million cy/year and process into high-grade arc. 1 Plasma, 5 million tile via plasma gas arc vitrification

• Contact specializing company to perform 2 Plasma, 5 million with Island further analysis for Conowingo Reservoir • Next Best Alternative after Plasma: Dredge 1 million cy/year and process 3 Plasma, 3 million with Island into lightweight aggregate with construction of artificial island 4 Plasma, 3 million

Future Work Lightweight Aggregate, 5 • Conduct additional cost benefit analysis with any 1 million with Island 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 52 Reservoir Questions?

53