Presenters: Sheri Gravette Kevin Cazenas Said Masoud Rayhan Ain

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1 Design of a Sediment Mitigation System for Conowingo Dam Presenters: Sheri Gravette Kevin Cazenas Said Masoud Rayhan Ain Sediment Plume Faculty Advisor: George Donohue Sponsor: Lower Susquehanna Riverkeeper

2 Agenda Context Stakeholders Problem/Need Statement Mission Requirements Design Alternatives Technical Approach Preliminary Results Project Management 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

3 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 Water Quality Flows through Pennsylvania and Maryland Quality of water is vital to the bay s health Improvement in water quality thus far can be attributed to US Army Corp.

4 Lower Susquehanna River and Water Quality Flows through Pennsylvania and Maryland Quality of water is vital to the bay s health Improvement in water quality thus far can be attributed to US Army Corp. of Engineers Provides power for turbines in hydroelectric plants and clean water to people Contains 4 Dams: York Haven, Safe Harbor, Holtwood, Conowingo York Haven, Safe Harbor and Holtwood have reached steady state - dam has completely silted up and is no longer able to retain sediment; dams are at maximum capacity Map of Conowingo Reservoir Source: US Army Corps of Engineers, (2013) 4

5 Conowingo Dam sediment Conowingo Dam Source: J. Schroath Constructed in 1928 Southernmost Dam of the Lower Susquehanna Location of Conowingo Hydroelectric Station Mainly provides power to Philadelphia, PA A black start power source Provides 1.6 billion kwh annually Traps sediment and nutrients from reaching the Chesapeake Bay Water quality is closely related to sediment deposition Traps ~1.5 million tons annually 5

Flow and Sediment in the Conowingo Reservoir Rouse Number: P = ω s u ω s =Sediment

Most of suspended sediment is located directly behind the dam (areas away from

6 Flow and Sediment in the Conowingo Reservoir Rouse Number: P = ω s u ω s =Sediment fall velocity u =shear velocity Holtwood Dam Rouse number defines a concentration profile of sediment Determines how sediment will be transported in flowing water Rate of particle fall velocity versus strength of turbulence acting to suspend the sediment Most 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

Probability 0.002 Probability of Flow Rate at Conowingo Dam (2010-2012) 0.0018 0.0016 0.0014 0.0012 0.

7 Probability Probability of Flow Rate at Conowingo Dam ( ) Steady State Transient Flow (cfs) Data Source: USGS, 96 rates/day 7

low-moderate rate Transient state: river flow rate higher than 300,000 cfs Major Scouring event: enhanced erosion of

8 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 Transient state: river flow rate higher than 300,000 cfs Major Scouring event: enhanced erosion of sediment due to significantly increased flow rates and constant interaction of water with the Dam Chesapeake Bay: Before and After Tropical Storm Lee Source: MODIS Rapid Response Team at NASA GSFC 8

9 Impact of Major Scouring Events on the Chesapeake Bay Natural Yearly Ecosystem Cycle vs. Effects of Previous Storms Source: Dennison, W.C., T. Saxby, B.M. Walsh, Eds. (2012). 9

10 Impact of Major Scouring Events on the Chesapeake Bay Natural Yearly Ecosystem Cycle vs. Effects of Previous Storms Source: Dennison, W.C., T. Saxby, B.M. Walsh, Eds. (2012). 10

DE, MD, WV, VA, and DC Sets limits for farmers, plants, dams, and other organizations that dump

11 Chesapeake Bay Total Maximum Daily Load (TMDL) Established by US Environmental Protection Agency in conjunction with Obama s 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 : 60% of sediment/nutrients reduction must be met 11

12 Susquehanna Contribution to TMDL Watershed limits to be attained by 2025 are as follows: 39,222 tons of nitrogen per year (46% of Chesapeake TMDL reduction) 1,719 tons of phosphorus per year (30% of Chesapeake TMDL reduction) 893,577tons of sediment per year (30% of Chesapeake TMDL reduction) 12

13 Project Scope Within Scope Main concern is mitigation of sediment/nutrients currently deposited directly behind dam Storm surge/scouring events, which is a transient problem (river flow rate > 300,000 cfs) Out of Scope Prevention of increased sediment/nutrients arriving from upriver (steady-state problem) Entirety of the Chesapeake Bay TMDL (steady-state problem) 13

14 Sediment Deposition (million tons) Percent Capacity Sediment Deposition at Conowingo Dam Sediment Deposition Expected Threshold Year Sediment Deposition in Conowingo Reservoir; Construction to 2008 with Gap Prediction Source of Data: Hirsch, R.M., (2012) 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% If sediment deposition reaches maximum capacity: Scouring events would further devastate the Chesapeake Bay ecosystem All Susquehanna River sediment would flow through to the Chesapeake Bay Deposition potential expected sediment deposited over a given time 14

15 Conowingo Reservoir: Relationship Between Scoured Sediment Load and Flow Rate Scoured Sediment Load (million tons) 14 Scoured sediment follows an exponential curve with relation to water flow Sediment Load Threshold Expon. (Sediment Load) y = e 4E-06x Current threshold set at a 75% decrease from the trend line Scour Potential expected sediment scoured with a given flow rate , , , ,000 1,000,000 Flow Rate (cfs) Sediment Scoured from Conowingo Reservoir Based on Flow Rate Source: LSRWA (2013) 15

16 Agenda Context Stakeholders Problem/Need Statement Mission Requirements Design Alternatives Technical Approach Preliminary Results Project Management 16

17 Primary Stakeholders Objective(s) Issue Lower Susquehanna Riverkeeper and Stewards of the Lower Susquehanna, Inc. (SOLs) Chesapeake Waterkeepers - 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 is high from Reservoir is high - Cost to remove sediment is high from Reservoir is high Maryland and Pennsylvania Residents (Lower Susquehanna Watershed) Exelon Generation owner of Conowingo Dam Federal Energy Regulatory Commission (FERC) - Maintain healthy waters for fishing and recreation - Improve water quality of the watershed - Receive allocated power from Hydroelectric Dam - Obtain relicensing of Conowingo Dam prior to its expiration in September Maintain profit - Aid consumers in obtaining reliable, efficient and sustainable energy services - Define regulations for energy providers - Cost to remove sediment is high from Reservoir is high - Sediment build up has no impact on energy production - Pressure to update dam regulations 17

18 Stakeholder Tensions and Interactions Aids in sediment removal Does not aid or potentially aids in sediment removal 18

19 Agenda Context Stakeholders Problem/Need Statement Mission Requirements Design Alternatives Technical Approach Preliminary Results Project Management 19

20 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 20

21 Need Statement Need to create a system to reduce the environmental impact of scouring events Need is met by reducing the sediment and nutrients currently trapped behind Conowingo Dam Reduction is to be done while maintaining energy production in order to help satisfy FERC standards, and eventual TMDL regulations. 21

22 Agenda Context Stakeholders Problem/Need Statement Mission Requirements Design Alternatives Technical Approach Preliminary Results Project Management 22

23 Mission Requirements MR.1 The system shall remove sediment from the reservoir at a load rate greater than or equal to 1.5 million tons annually. MR.2 The system shall reduce sediment scouring potential by 75%. 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 39,222 tons of nitrogen, 1,719 tons of phosphorus, and 893,577 tons of sediment per year by MR.5 The system shall facilitate submerged aquatic vegetation (SAV) growth in the Chesapeake Bay. 23

24 Agenda Context Stakeholders Problem/Need Statement Mission Requirements Design Alternatives Technical Approach Preliminary Results Project Management 24

Sediment Mitigation Alternatives 1. No Mitigation Techniques Sediment remains in reservoir 2. Hydraulic Dredging Sediment removed from waters Product made from sediment 3.

25 Sediment Mitigation Alternatives 1. No Mitigation Techniques 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) 25

26 1. No Mitigation Techniques 2. Hydraulic Dredging 3. Dredging & Artificial Island WHAT Sediment will reach capacity Major scouring events will occur HOW Normal Flow: < 30,000 cfs Major Scouring Event: > 300,000 cfs Normal Flow at Conowingo Dam Source: E. Malumuth (2012) 26

27 1. No Mitigation Techniques 2. Hydraulic Dredging 3. Dredging & Artificial Island WHAT Remove sediment mechanically Concentration on suspended sediment Product yield from sediment HOW Rotating cutter to agitate & stir up Pipeline pumps sediment to surface Collection for further treatment Hydraulic Dredging Process Source: C. Johnson 27

28 1. No Mitigation Techniques 2. Hydraulic Dredging 3. Dredging & Artificial Island 2.1 Quarry 2.2 Rotary Kiln 2.3 Low Temperature Washing 2.4 Plasma Gas Arc Vitrification Quarry Direct transportation from reservoir to quarry No opportunity to offset cost Rock Quarry 28

29 Probability 1. No Mitigation Techniques 2. Hydraulic Dredging 3. Dredging & Artificial Island 2.1 Quarry Quarry Cost/Revenue Distribution s(triangular) Min. Cost (cy) 2.2 Rotary Kiln Mid. Cost (cy) 2.3 Low Temperature Washing Max Cost (cy) 2.4 Plasma Gas Arc Vitrification $36 $48 $ Cost PDF (Triangular) Quarry $30 $40 $50 $60 Cost Revenue Source: LSRWA 29

30 1. No Mitigation Techniques 2. Hydraulic Dredging 3. Dredging & Artificial Island Rotary Kiln (Lightweight Aggregate) Thermal decontamination process Process includes: debris removal Dewatering Pelletizing Extrusion of dredged material 2.1 Quarry 2.3 Low Temperature 2.4 Plasma Gas Arc 2.2 Rotary Kiln Washing Vitrification Rotary Kiln Operation 30

31 Probability 1. No Mitigation Techniques 2. Hydraulic Dredging 3. Dredging & Artificial Island Lightweight Aggregate Cost/Revenue Distribution (Triangular) Min. Cost (cy) 2.1 Quarry 2.3 Low Temperature 2.4 Plasma Gas Arc 2.2 Rotary Kiln Washing Vitrification Mid. Cost (cy) Max Cost (cy) Min Revenue (cy) Mid Revenue (cy) Max Revenue (cy) $52 $70 $80 $40 $65 $ Cost/Revenue PDF (Triangular) Lightweight Aggregate Potential to be profitable Adjusted for inflation Source: JCI/Upcycle Associates, LLC Revenue Cost 0 $0 $50 $100 $150 Monetary Value 31

Non-thermal Decontamination Potential use as manufactured topsoil

32 1. No Mitigation Techniques 2. Hydraulic Dredging 3. Dredging & Artificial Island 2.1 Quarry 2.3 Low Temperature 2.4 Plasma Gas Arc 2.2 Rotary Kiln Washing Vitrification Low-Temperature Sediment Washing Non-thermal Decontamination Potential use as manufactured topsoil Process includes: Loose screening Dewatering Aeration Sediment washing/remediation Oxidation and cavitation Low Temperature Washing Facility Manufactured Topsoil 32

33 Probability 1. No Mitigation Techniques 2. Hydraulic Dredging 3. Dredging & Artificial Island 2.1 Quarry 2.3 Low Temperature 2.4 Plasma Gas Arc 2.2 Rotary Kiln Washing Vitrification Low-Temperature Sediment Washing : Topsoil Cost/Revenue Distribution (Triangular) Min. Cost (cy) Mid. Cost (cy) Max Cost (cy) Min Revenue (cy) Mid Revenue (cy) $48 $56 $58 $15 $18 $25 Max Revenue (cy) Cost/Revenue PDF (Triangular) Topsoil No profit potential Adjusted for inflation Sources: M. Lawler et al and D. Pettinelli Revenue Cost 0 $0 $20 $40 $60 $80 Monetary Value 33

1. No Mitigation Techniques 2. Hydraulic Dredging 3. Dredging & Artificial Island 2.1 Quarry 2.3 Low Temperature 2.2 Rotary Kiln Washing Plasma Gas Arc Vitrification (Glass Aggregate) 99.

34 1. No Mitigation Techniques 2. Hydraulic Dredging 3. Dredging & Artificial Island 2.1 Quarry 2.3 Low Temperature 2.2 Rotary Kiln Washing Plasma Gas Arc Vitrification (Glass Aggregate) % Decontamination and incineration of all organic compounds Intense thermal decontamination process Output: vitrified glassed compound slag 2.4 Plasma Gas Arc Vitrification Glass Aggregate (Slag) 34

35 Probability Probability 1. No Mitigation Techniques 2. Hydraulic Dredging 3. Dredging & Artificial Island 2.1 Quarry 2.3 Low Temperature 2.2 Rotary Kiln Washing 2.4 Plasma Gas Arc Vitrification Slag Products : Cost/Revenue Distribution (Triangular) Product Arc. Tile (high grade) Arc. Tile (low grade) Min. Cost (cy) Mid. Cost (cy) Max Cost (cy) Min Revenue (cy) Mid Revenue (cy) Max Revenue (cy) $120 $146 $157 $247 $268 $322 $120 $146 $157 $193 $203 $219 High potential to be profitable Source: Westinghouse Cost/Revenue PDF (Triangular) High Grade Tile Cost/Revenue PDF (Triangular) Low Grade Tile Revenue Cost Revenue Cost 0 0 $100 $150 $200 $250 $300 Monetary Value $100 $150 $200 Monetary Value 35

of the dam Larger sediment load through the dam (at steady-state); remaining amount is dredged

velocity Decreases Rouse number near suspended sediment Sediment mixed into wash load

36 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) 36

37 Agenda Context Stakeholders Problem/Need Statement Mission Requirements Design Alternatives Technical Approach Preliminary Results Project Management 37

38 Level One: Sediment Management Model 38

39 Model Simulates Potential Models Sediment Mitigation Model Sediment flow from upstream and sediment outflow at Conowingo Dam - Reproduction Model - Diversion Alternative: Bernoulli Equation Ecological Impact Model Ecological impact of the sediment levels on the Chesapeake Bay ecosystems - US Army Corp. of Engineering Eco Model (TBD) Reuse-Business Model Sediment product production and revenue generation - Monte Carlo Simulation (MS Excel) 39

40 Level Two: Sediment Management Model 40

41 No Mitigation Techniques 41

42 Sediment Mitigation Equations Bernoulli Equation: P ρv ρgh 1 = P ρv ρgh 2 Rouse Number: Z = w s κu Shear vs. Mean Flow Velocity Source: MIT u 1 10 v P = pressure ρ = density v = mean flow velocity g = gravity constant h = height Z = Rouse number w s = particle fall velocity κ = Von Kármán constant u = shear velocity When mean flow velocity increases, Rouse number decreases (Rouse number < 0.8 indicates particle movement) 42

43 Ecological Impact Equation Flow Rate vs. Scouring Discharge: y = e x x = Daily Average Flow Rate (cfs) y = Scouring Discharge Load (SDL) (tons/day) Source: Trendline from LSRWA data Varying sediment discharge levels can be found given varying flow rates Possibility to compare with the following statistics based on use case data: Current bay sediment, nitrogen, phosphorus, and SAV growth Equation only valid for current reservoir status (no mitigation) Dredging alternatives will require separate equations based on output from sediment mitigation model 43

44 Business / Reuse Equations Production Equation: R i a i = p i Mitigation Cost Percentage m i = T i M x 100 Revenue Equation: T i = rev i c i p i a i = amount of sediment needed to make one unit of product i R i = amount of sediment removed and used for product i p i = units of product i produced rev i = c i = revenue per unti product i cost per unti product i T i = total revenue generated by product i M x = mitigation cost for alternative x m i = % mitigation costs offset by product i 44

45 Design of Experiment Inputs Outputs Alternative Flow Rate Sediment Amount Dredged Season Sediment Amount Scoured Total Alt. Costs w/ Mitigation Cost % Ecological Impact Cost % N, P increases 300,000 cfs A Spring B Spring C Spring 600,000 cfs A Spring B Spring No Mitigation C Spring 1,000,000 cfs A Spring B Spring C Spring 300,000 cfs A Spring B Spring C Spring 600,000 cfs A Spring B Spring Hydraulic Dredging C Spring 1,000,000 cfs A Spring B Spring C Spring 300,000 cfs A Spring B Spring C Spring 600,000 cfs A Spring B Spring Dredging and Artificial Island C Spring 1,000,000 cfs A Spring B Spring C Spring 45

46 Design of Experiment Inputs Outputs Alternative Flow Rate Sediment Amount Dredged Season Sediment Amount Scoured Total Alt. Costs w/ Mitigation Cost % Ecological Impact Cost % N, P increases 300,000 cfs A Spring B Spring C Spring 600,000 cfs A Spring B Spring No Mitigation C Spring 1,000,000 cfs A Spring B Spring C Spring 46

47 Design of Experiment Inputs Outputs Alternative Flow Rate Sed. Amount Dredged Season Sed. Amount Scoured Total Alt. Costs w/ Mitigation Cost % Ecological Impact Cost % N,P increase A* Spring No Mitigation 300,000 cfs B* Spring C* Spring 47

48 Value Hierarchy Sediment Deposition Potential Minimize Ecological Impact Sediment Scour Potential Reliability Sediment Deposition Potential expected sediment deposited over a given time Sediment Scour Potential - expected sediment scoured with a given flow rate Reliability dependability on the specified functioning of a system over an extended period of time U = π SDP w SDP + π SSP w SSP +π R w R π = alternative i s score w = means objective weight* * All weights are TBD 48

49 Agenda Context Stakeholders Problem/Need Statement Mission Requirements Design Alternatives Technical Approach Preliminary Results Project Management 49

50 Preliminary Analysis 1,000,000 = 3% cubic yards sediment dredged decrease in scour potential 75% = 25,000,000 set requirement percentage cubic yards to be removed 5,000,000 = 5* optimal cubic yards removed per year years to satisfy requirement *Assumes linear scour potential decrease. Does not factor in sediment redeposition. Source: Estimations from LSRWA 50

51 Preliminary Analysis 1,000,000 = 6% cubic yards sediment dredged increase in deposition potential 1,000,000 cubic yards sediment removed 74,000 additional cubic yards deposited in one year (6% of 1,310,000 cubic yards) = = 0.40% reservoir capacity decrease 0.03% reservoir capacity increase after one year *Based on annual deposition rate of 1,230,000 cubic yards per year from Source: Estimations from LSRWA 0.37%* total capacity reservoir decrease per year 51

52 Agenda Context Stakeholders Problem/Need Statement Mission Requirements Design Alternatives Technical Approach Preliminary Results Project Management 52

53 Work Breakdown Structure (WBS) 53

54 Project Schedule 54

55 Budget Calculation $35 + $39 = $74 (per hour) Hourly Rate 47.25% GMU Overhead Total Rate $74 * 1400 $104,000 Total Rate Total Planned Hours Budget at Completion 55

56 Cost $120,000 $100,000 Earned Value Management Conference Extended Abstract IEEE Version 2 Final & Conference/ Poster/Video $80,000 Proposal Final & Draft Conference/Poster SIEDS Conference Capstone Conference $60,000 $40,000 Preliminary Project Plan Final Project Plan $20,000 Faculty Presentations $ Week PV (10%) PV (50%) PV (90%) AC EV 56

57 Ratio 3. Cost Performance Index (CPI) vs. Schedule Performance Index (SPI) Week CPI SPI 57

58 Project Risks Risk Model Design: Learning Curve for design of 3 different models Model Design: Data necessary for modeling cost to Chesapeake Bay is a work in progress Model Design: Product values may be bias due to overly optimistic estimations. Mitigation Find programs we would like to use & try to find a favorable tradeoff between what we know and what needs to be learned in terms of programming Supplement similar data from another study. Skewed data pessimistically to the uncertainty due to bias. Stakeholders: Unable to arrange further contact with Exelon Call initial contact with Exelon and leave a message until there is a response with requested information 58

59 Questions? 59

Design of a Sediment Removal and Processing System to Reduce Sediment Scouring Potential from the Lower Susquehanna River Dams

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