Design of a Sediment Mitigation System for Conowingo Dam Presenters: Sheri Gravette Kevin Cazenas Said Masoud Rayhan Ain Sediment Plume

Home , Rouse number

Sponsor: Faculty Advisor: Lower George Donohue Susquehanna Riverkeeper 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 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. 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 Conowingo Dam

• Constructed in 1928 • Southernmost Dam of the Lower Susquehanna sediment • 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 Conowingo Dam deposition Source: J. Schroath – Traps ~1.5 million tons annually

5 Flow and Sediment in the Conowingo Reservoir

• Rouse Number: 휔 푃 = 푠 푢∗

휔푠=Sediment fall velocity 푢∗=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 Conowingo Dam turbines)

Rouse Number for Medium Silt Particle at 30,000 cfs 6 Source: S. Scott (2012) Probability of Flow Rate at Conowingo Dam (2010-2012) 0.002

0.0018

0.0016

0.0014

0.0012

0.001 Steady State

Probability 0.0008 Transient 0.0006

0.0004

0.0002

Flow (cfs) 7 Data Source: USGS, 96 rates/day 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 – Major Scouring event: enhanced erosion Bay at low-moderate rate 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 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 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 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 2025 – 2017: 60% of sediment/nutrients reduction must be met

11 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 Project Scope

Within Scope Out of Scope

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

13 Sediment Deposition at Conowingo Dam

100% 200 Sediment Deposition • If sediment deposition

Expected 90%

) Threshold reaches maximum 80% capacity: 150 70% • Scouring events would

(million tons (million 60% further devastate the Chesapeake Bay 50% 100 ecosystem

40% • All Susquehanna River Percent Capacity Percent 30% sediment would flow 50 20% through to the Chesapeake Sediment Deposition Deposition Sediment Bay 10% • Deposition potential – 0 0% 1929 1936 1943 1950 1957 1964 1971 1978 1985 1992 1999 2006 2013 2020 2027 expected sediment Year Sediment Deposition in Conowingo Reservoir; Construction to 2008 with Gap Prediction deposited over a given Source of Data: Hirsch, R.M., (2012) time

14 Conowingo Reservoir: Relationship Between Scoured Sediment Load and Flow Rate

Sediment Load

• Scoured sediment y = 221373e4E-06x

follows an exponential ) 12 Threshold Expon. (Sediment Load) curve with relation to 10

water flow (million tons (million 8 • Current threshold set at a 75% decrease 6 from the trend line 4

• Scour Potential – Scoured Sediment Load Load Sediment Scoured expected sediment 2

scoured with a given 0 flow rate 0 200,000 400,000 600,000 800,000 1,000,000 Flow Rate (cfs) Sediment Scoured from Conowingo Reservoir Based on Flow Rate Source: LSRWA (2013) 15 Agenda

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

16 Primary Stakeholders Objective(s) Issue Lower Susquehanna - Find alternative uses for the sediment - Cost to remove sediment is high from Riverkeeper and Stewards of stored behind Conowingo Dam Reservoir is high the Lower Susquehanna, Inc. - Highlight vulnerabilities in (SOLs) environmental law - Minimize effects of major scouring events to the Chesapeake Bay Chesapeake Waterkeepers - Protect and improve the health of the - Cost to remove sediment is high from Chesapeake Bay and waterways in the Reservoir is high region

Maryland and Pennsylvania - Maintain healthy waters for fishing and - Cost to remove sediment is high from Residents (Lower recreation Reservoir is high Susquehanna Watershed) - Improve water quality of the watershed - Receive allocated power from Hydroelectric Dam Exelon Generation – owner of - Obtain relicensing of Conowingo Dam - Sediment build up has no impact on Conowingo Dam prior to its expiration in September energy production 2014 - Maintain profit Federal Energy Regulatory - Aid consumers in obtaining reliable, - Pressure to update dam regulations Commission (FERC) efficient and sustainable energy services - Define regulations for energy providers 17 Stakeholder Tensions and Interactions

------Aids in sediment removal ------Does not aid or potentially aids in sediment removal 18 Agenda

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

19 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 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 Agenda

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

22 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 2025. MR.5 The system shall facilitate submerged aquatic vegetation (SAV) growth in the Chesapeake Bay.

23 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. 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 1. No Mitigation 2. Hydraulic 3. Dredging & Techniques Dredging Artificial Island

WHAT HOW • Sediment will reach capacity • Normal Flow: < 30,000 cfs • Major scouring events will • Major Scouring Event: > 300,000 cfs occur

Normal Flow at Conowingo Dam 26 Source: E. Malumuth (2012) 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 27 1. No Mitigation 2. Hydraulic 3. Dredging & Techniques Dredging Artificial Island

2.3 Low Temperature 2.4 Plasma Gas Arc 2.1 Quarry 2.2 Rotary Kiln Washing Vitrification Quarry • Direct transportation from reservoir to quarry • No opportunity to offset cost

Rock Quarry

28 1. No Mitigation 2. Hydraulic 3. Dredging & Techniques Dredging Artificial Island

2.3 Low Temperature 2.4 Plasma Gas Arc 2.1 Quarry 2.2 Rotary Kiln Washing Vitrification Quarry Cost/Revenue Distribution s(Triangular) Min. Cost Mid. Cost Max Cost (cy) (cy) (cy)

$36 $48 $54

Cost PDF (Triangular) Source: LSRWA Quarry 0.12

0.1

0.08 0.06 0.04

Probability Revenue 0.02 0 $30 $40 $50 $60 29 Cost 1. No Mitigation 2. Hydraulic 3. Dredging & Techniques Dredging Artificial Island

2.3 Low Temperature 2.4 Plasma Gas Arc 2.1 Quarry 2.2 Rotary Kiln Washing Vitrification Rotary Kiln (Lightweight Aggregate) • Thermal decontamination process • Process includes: – debris removal – Dewatering – Pelletizing – Extrusion of dredged material

Rotary Kiln Operation

30 1. No Mitigation 2. Hydraulic 3. Dredging & Techniques Dredging Artificial Island

2.3 Low Temperature 2.4 Plasma Gas Arc 2.1 Quarry 2.2 Rotary Kiln Washing Vitrification Lightweight Aggregate Cost/Revenue Distribution (Triangular) Min. Cost Mid. Cost Max Cost Min Mid Max (cy) (cy) (cy) Revenue Revenue Revenue (cy) (cy) (cy) $52 $70 $80 $40 $65 $100

Cost/Revenue PDF (Triangular) • Potential to be profitable Lightweight Aggregate • Adjusted for inflation 0.08 Source: JCI/Upcycle Associates, LLC

0.06

0.04 Revenue Probability 0.02 Cost

0 $0 $50 $100 $150 31 Monetary Value 1. No Mitigation 2. Hydraulic 3. Dredging & Techniques Dredging Artificial Island

2.3 Low Temperature 2.4 Plasma Gas Arc 2.1 Quarry 2.2 Rotary Kiln Washing Vitrification Low-Temperature Sediment Washing • Process includes: • Non-thermal Decontamination – Loose screening • Potential use as manufactured – Dewatering topsoil – Aeration – Sediment washing/remediation – Oxidation and cavitation

Low Temperature Washing Facility Manufactured Topsoil 32 1. No Mitigation 2. Hydraulic 3. Dredging & Techniques Dredging Artificial Island

2.3 Low Temperature 2.4 Plasma Gas Arc 2.1 Quarry 2.2 Rotary Kiln Washing Vitrification

Low-Temperature Sediment Washing : Topsoil Cost/Revenue Distribution (Triangular) Min. Cost Mid. Cost Max Cost Min Mid Max (cy) (cy) (cy) Revenue Revenue Revenue (cy) (cy) (cy) $48 $56 $58 $15 $18 $25

Cost/Revenue PDF (Triangular) Topsoil • No profit potential 0.25 • Adjusted for inflation

0.2 Sources: M. Lawler et al and D. Pettinelli

0.15

0.1 Revenue Probability 0.05 Cost

0 $0 $20 $40 $60 $80 33 Monetary Value 1. No Mitigation 2. Hydraulic 3. Dredging & Techniques Dredging Artificial Island

2.3 Low Temperature 2.4 Plasma Gas Arc 2.1 Quarry 2.2 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”

Glass Aggregate (Slag) 34 1. No Mitigation 2. Hydraulic 3. Dredging & Techniques Dredging Artificial Island

2.3 Low Temperature 2.4 Plasma Gas Arc 2.1 Quarry 2.2 Rotary Kiln Washing Vitrification

Slag Products : Cost/Revenue Distribution (Triangular) Product Min. Cost Mid. Cost Max Cost Min Mid Max (cy) (cy) (cy) Revenue Revenue Revenue (cy) (cy) (cy) • High potential to Arc. Tile (high $120 $146 $157 $247 $268 $322 grade) be profitable Arc. Tile (low $120 $146 $157 $193 $203 $219 Source: grade) Westinghouse

Cost/Revenue PDF (Triangular) Cost/Revenue PDF (Triangular) High Grade Tile Low Grade Tile

0.06 0.1

0.05 0.08 0.04 0.06 0.03 Revenue 0.04 Revenue

0.02

Probability Probability 0.01 Cost 0.02 Cost 0 0 $100 $150 $200 $250 $300 $100 $150 $200 35 Monetary Value Monetary Value 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 Potential Artificial Island Location at Conowingo Reservoir • Potentially decreases total dredging costs Source: Original graphic by S. Scott (2012) 36

Agenda

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

37 Level One: Sediment Management Model

38 Model Simulates Potential Models

Sediment flow from upstream - Reproduction Model and sediment outflow at - Diversion Alternative: Conowingo Dam Bernoulli Equation Sediment Mitigation Model

Ecological impact of the - US Army Corp. of sediment levels on the Engineering Eco Model (TBD) Chesapeake Bay ecosystems Ecological Impact Model

Sediment product production - Monte Carlo Simulation (MS and revenue generation Excel) Reuse-Business Model

39 Level Two: Sediment Management Model

40 No Mitigation Techniques

41 Sediment Mitigation Equations

Bernoulli Equation: Rouse Number: 1 1 푤푠 2 2 푍 = 푃1 + 휌푣1 + 휌𝑔ℎ1 = 푃2 + 휌푣2 + 휌𝑔ℎ2 2 2 κ푢∗

푃 = pressure 푍 = Rouse number Shear vs. Mean Flow Velocity 휌 = density 푤푠 = particle fall velocity 1 푣 = mean flow velocity 푢∗ ≈ 푣 κ = Von Kármán constant 10 𝑔 = gravity constant 푢 = shear velocity Source: MIT ℎ = height ∗

When mean flow velocity increases, Rouse number decreases (Rouse number < 0.8 indicates particle movement) 42 Ecological Impact Equation

Flow Rate vs. Scouring Discharge: 푦 = 221373 ∗ 푒0.000004푥 푥 = Daily Average Flow Rate (cfs) 푦 = 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 Business / Reuse Equations

Production Equation: Revenue Equation: 푅 푖 푇푖 = 푟푒푣푖 − 푐푖 ∗ 푝푖 = 푝푖 푎푖

푎𝑖 = amount of sediment needed to make one unit of product i

R amount of sediment removed and used for product i Mitigation Cost Percentage i = p = units of product i produced 푇푖 𝑖 rev revenue per unti product 𝑖 푚푖 = ∗ 100 𝑖 = c cost per unti product 𝑖 푀푥 𝑖 =

Ti = total revenue generated by product i M = mitigation cost for alternative x x

m𝑖 = % mitigation costs offset by product i

44 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 Summer Winter Fall B Spring Summer Winter Fall C Spring Summer Winter Fall 600,000 cfs A Spring Summer Winter Fall B Spring Summer No Mitigation Winter Fall C Spring Summer Winter Fall 1,000,000 cfs A Spring Summer Winter Fall B Spring Summer Winter Fall C Spring Summer Winter Fall 300,000 cfs A Spring Summer Winter Fall B Spring Summer Winter Fall C Spring Summer Winter Fall 600,000 cfs A Spring Summer Winter Fall B Spring Summer Hydraulic Dredging Winter Fall C Spring Summer Winter Fall 1,000,000 cfs A Spring Summer Winter Fall B Spring Summer Winter Fall C Spring Summer Winter Fall 300,000 cfs A Spring Summer Winter Fall B Spring Summer Winter Fall C Spring Summer Winter Fall 600,000 cfs A Spring Summer Winter Fall B Spring Summer Dredging and Artificial Island Winter Fall C Spring Summer Winter Fall 1,000,000 cfs A Spring Summer Winter Fall B Spring Summer Winter Fall C Spring Summer Winter Fall

45 Design of Experiment

46 Design of Experiment

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

Winter Summer C* Spring Fall

47 Value Hierarchy

Sediment Deposition Potential – expected sediment deposited over Minimize a given time Ecological Impact Sediment Scour Potential - expected sediment scoured with a given flow rate Sediment Sediment Scour Deposition Reliability Reliability – dependability on the Potential Potential specified functioning of a system over an extended period of time

푈 = 휋푆퐷푃푤푆퐷푃 + 휋푆푆푃푤푆푆푃+휋푅푤푅 휋 = alternative i’s score 푤 = means objective weight*

* All weights are TBD 48 Agenda

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

49 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 years to satisfy requirement removed per year

*Assumes linear scour potential decrease.

Does not factor in sediment redeposition. 50 Source: Estimations from LSRWA Preliminary Analysis

1,000,000 = 6% cubic yards sediment dredged increase in deposition potential

= 1,000,000 0.40% cubic yards sediment removed reservoir capacity decrease

74,000 = 0.03% 0.37%* total capacity reservoir additional cubic yards reservoir capacity increase decrease per year deposited in one year after one year (6% of 1,310,000 cubic yards) *Based on annual deposition rate of

1,230,000 cubic yards per year from 1996-2008 51 Source: Estimations from LSRWA Agenda

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

52 Work Breakdown Structure (WBS)

53 Project Schedule

54 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 Earned Value Management Final & Conference/ Poster/Video $120,000 IEEE Version 2 Conference Extended Abstract $100,000

SIEDS Conference $80,000 Proposal Final & Draft Capstone Conference

Conference/Poster

$60,000 Final Project Cost Plan

$40,000 Preliminary Project Plan

$20,000 Faculty Presentations

$0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 Week 56 PV (10%) PV (50%) PV (90%) AC EV Cost Performance Index (CPI) vs.

3. Schedule Performance Index (SPI)

2.5

1.5 Ratio

0.5

0. 1 2 3 4 5 6 7 8 9 10 11 Week

CPI SPI

57 Project Risks

Risk Mitigation

Find programs we would like to use & try to find a Model Design: favorable tradeoff between what we know and Learning Curve for design of 3 different models what needs to be learned in terms of programming

Model Design: Data necessary for modeling cost to Chesapeake Bay Supplement similar data from another study. is a work in progress

Model Design: Skewed data pessimistically to the uncertainty due Product values may be bias due to overly optimistic to bias. estimations.

Call initial contact with Exelon and leave a Stakeholders: message until there is a response with requested Unable to arrange further contact with Exelon information

58 Questions?