Table of Contents
Acknowledgments
Authors and Contributing Authors
Authors
Contributing Authors
Haestad Methods
Thomas Walski, PhD, PE
Donald V. Chase, PhD, PE
Dragan A. Savic, PhD, CEng
Walter Grayman, PhD, PE
Stephen Beckwith, PhD
Edmundo Koelle, PhD
Scott Cattran, MS
Rick Hammond, MS
Kevin Laptos, PE
Steven G. Lowry, PE
Robert F. Mankowski, PE
Stan Plante, PE
John Przybyla, PE
Barbara A. Schmitz
Foreword
Preface
Chapter Overview
Continuing Education and Problem Sets
Feedback
Continuing Education Units
Notes on Completing the Exercises
About the Software
1. Introduction to Water Distribution Modeling
1.1 Anatomy of a Water Distribution System
Sources of Potable Water
Customers of Potable Water
Transport Facilities
Transmission and Distribution Mains
System Configurations
1.2 What Is a Water Distribution System Simulation?
1.3 Applications of Water Distribution Models
Long-Range Master Planning
Rehabilitation
Fire Protection Studies
Water Quality Investigations
Energy Management
Daily Operations
Operator Training
Emergency Response
System Troubleshooting
1.4 The Modeling Process
1.5 A Brief History of Water Distribution Technology
References
2. Modeling Theory
2.1 Fluid Properties
Density and Specific Weight
Viscosity
Fluid Compressibility
Vapor Pressure
2.2 Fluid Statics and Dynamics
Static Pressure
Absolute Pressure and Gage Pressure
Velocity and Flow Regime
Reynolds Number
Velocity Profiles
2.3 Energy Concepts
Energy Losses
2.4 Friction Losses
Darcy-Weisbach Formula
Colebrook-White Equation and the Moody Diagram
Swamee-Jain Formula
Hazen-Williams
Manning Equation
Comparison of Friction Loss Methods
2.5 Minor Losses
Valve Coefficient
Equivalent Pipe Length
2.6 Resistance Coefficients
Darcy-Weisbach
Hazen-Williams
Manning
Minor Losses
2.7 Energy Gains - Pumps
Pump Head-Discharge Relationship
Affinity Laws for Variable-Speed Pumps
System Head Curves
Pump Operating Point
Other Uses of Pump Curves
2.8 Network Hydraulics
Conservation of Mass
Conservation of Energy
Solving Network Problems
2.9 Water Quality Modeling
Transport in Pipes
Mixing at Nodes
Mixing in Tanks
Chemical Reaction Terms
Bulk Reactions
Bulk and Wall Reactions
Formation Reactions
Other Types of Water Quality Simulations
Source Trace Analysis
Water Age Analysis
Solution Methods
The Eulerian Approach
The Lagrangian Approach
References
Discussion Topics and Problems
3. Assembling a Model
3.1 Maps and Records
System Maps
Topographic Maps
As-Built Drawings
Electronic Maps and Records
Nongraphical Data
Computer-Aided Drafting
Geographic Information Systems
3.2 Model Representation
Network Elements
Naming Conventions (Element Labels)
Boundary Nodes
Network Topology
False Intersections
Converting CAD Drawings into Models
3.3 Reservoirs
3.4 Tanks
Hydropneumatic Tanks
3.5 Junctions
Junction Elevation
Selecting an Elevation
3.6 Pipes
Length
Scaled versus Schematic
Diameter
Minor Losses
Composite Minor Losses
3.7 Pumps
Pump Characteristic Curves
Fixed-Speed and Variable-Speed Pumps
Power and Efficiency
Obtaining Pump Data
Model Representation
Selecting Representative Points
Constant Power Pumps
Node versus Link Representation
Red Water
Positive Displacement Pumps
3.8 Valves
Isolation Valves
Directional Valves
Altitude Valves
Air Release Valves and Vacuum Breaking Valves
Control Valves
Pressure Reducing Valves (PRVs)
Pressure Sustaining Valves (PSVs)
Flow Control Valves (FCVs)
Throttle Control Valves (TCVs)
Valve Books
3.9 Controls (Switches)
Pipe Controls
Pump Controls
Regulating Valve Controls
Indicators of Control Settings
3.10 Types of Simulations
Steady-State Simulation
Extended-Period Simulation
EPS Calculation Process
Simulation Duration
Hydraulic Time Step
Intermediate Changes
Other Types of Simulations
Why Use a Scenario Manager?
3.11 Skeletonization
Skeletonization Example
Skeletonization Guidelines
Opposing Philosophies
Somewhere in the Middle
Elements of High Importance
Elements of Unknown Importance
Automated Skeletonization
Simple Pipe Removal
Removing Branch Pipes
Removing Pipes in Series (with no other pipes connected to the common node)
Removing Parallel Pipes
Removing Pipes to Break Loops
Summary of Basic Pipe Removals
Removing Nonpipe Elements
Complex Skeletonization
Stopping Criteria
Skeletonization Conclusions
3.12 Model Maintenance
References
Discussion Topics and Problems
4. Water Consumption
4.1 Baseline Demands
Data Sources
Pre-Existing Compiled Data
System Operational Records
Customer Meters and Billing Records
Spatial Allocation of Demands
Using GIS for Demand Allocation
Meter Assignment
Meter Aggregation
Flow Distribution
Point Demand Assignment
Projection of Future Demands
Categorizing Demands
Composite Demands
Nomenclature
Mass Balance Technique
Using Unit Demands
Unaccounted-For Water
Leakage
Meter Under Registration
Unmetered Usage
Demands in the United Kingdom
4.2 Demand Multipliers
Peaking Factors
Demands in Systems with High Unaccounted-For Water
Commercial Building Demands
4.3 Time-Varying Demands
Diurnal Curves
Developing System-Wide Diurnal Curves
Time Increments
Developing Customer Diurnal Curves
Data Logging for Customer Usage
Representative Customers
Defining Usage Patterns within a Model
Stepwise and Continuous Patterns
Pattern Start Time and Repetition
4.4 Projecting Future Demands
Historical Trends
Spatial Allocation of Future Demands
Disaggregated Projections
Population Estimates
Land Use
4.5 Fire Protection Demands
References
Discussion Topics and Problems
Conducting a Tracer Test
5. Testing Water Distribution Systems
5.1 Testing Fundamentals
Pressure Measurement
Flow Measurement
Potential Pitfalls in System Measurements
5.2 Fire Hydrant Flow Tests
Pitot Gages and Diffusers
Potential Problems with Fire Flow Tests
Using Fire Flow Tests for Calibration
Evaluating Distribution Capacity with Hydrant Tests
5.3 Head Loss Tests
Two-Gage Test
Parallel-Pipe Test
Potential Problems with Head Loss Tests
Using Head Loss Test Results for Calibration
5.4 Pump Performance Tests
Head Characteristic Curve
Pump Efficiency Testing
Potential Problems with Pump Performance Tests
Using Pump Performance Test Data for Calibration
5.5 Extended-Period Simulation Data
Distribution System Time-Series Data
Conducting a Tracer Test
Bottle Test Procedure
5.6 Water Quality Sampling
Laboratory Testing
Bulk Reaction Coefficients
Field Studies
Determining Actual Pipe Diameters.
Measuring Chlorine Wall Demand
Intensive Water Quality Surveys
5.7 Sampling Distribution System Tanks and Reservoirs
Water Quality Studies
Tracer Studies
Tracer Chemicals
Tracer Injection
Tracer Dosage
Monitoring Locations and Frequency
Regulatory Approval
Flow Measurements
Temperature Monitoring
5.8 Quality of Calibration Data
Impact on Optimized Calibration
Sources of Error in Calibration Data
References
Discussion Topics and Problems
6. Using SCADA Data for Hydraulic Modeling
6.1 Types of SCADA Data
6.2 Polling Intervals and Unsolicited Data
Using Hydraulic Models to Assist in SCADA Setup
6.3 SCADA Data Format
6.4 Managing SCADA Data
6.5 SCADA Data Errors
Data Compression Problems
Timing Problems
Missing Data
Instrumentation
Unknown Elevations
Other Error Sources
Integrating SCADA Systems and Hydraulic Models: Two Sample Applications
Estimating parameters at non-SCADA locations
Estimating Water Loss during Main Breaks
6.6 Responding to Data Problems
6.7 Verifying Data Validity
References
7. Calibrating Hydraulic Network Models
7.1 Model-Predicted versus Field-Measured Performance
Comparisons Based on Head
Location of Data Collection
7.2 Sources of Error in Modeling
Types of Errors
Nominal versus Actual Pipe Diameters
Internal Pipe Roughness Values
Compensating Errors
Distribution of System Demands
System Maps
Temporal Boundary Condition Changes
Model Skeletonization
Geometric Anomalies
Pump Characteristic Curves
7.3 Calibration Approaches
Manual Calibration Approaches
What Should Be Adjusted
Adjusting Roughness Coefficients
Automated Calibration Approaches
Optimization Problem Formulation
Issues with Calibration
Sampling Design for Calibration
Using Optimized Calibration
Model Validation
7.4 EPS Model Calibration
Parameters for Adjustment
Calibration Problems
Calibration Using Tracers
Energy Studies
7.5 Calibration of Water Quality Models
Source Concentrations
Initial Conditions
Predicting Initial Conditions
Setting Initial Conditions
Wall Reaction Coefficients
Calibration/Validation Using Time-Series Data
7.6 Acceptable Levels of Calibration
References
Discussion Topics and Problems
8. Using Models for Water Distribution System Design
8.1 Applying Models to Design Applications
Extent of Calibration and Skeletonization
Design Flow
Reliability Considerations
Key Roles in Design Using a Model
Types of Modeling Applications
Pipe Sizing Decisions
8.2 Identifying and Solving Common Distribution System Problems
Undersized Piping
Inadequate Pumping
Consistent Low Pressure
High Pressures During Low Demand Conditions
Oversized Piping
What's the Maximum Permissible Velocity in a Pipe?
8.3 Pumped Systems
Pumping into a Closed System with No Pressure Control Valve
Pumping into a Closed System with Pressure Control
Variable-Speed Pumps
Pumping into a System with a Storage Tank
Pumping into Closed System with Pumped Storage
Pumping into Hydropneumatic Tanks
Well Pumping
Pumps in Parallel
Head Loss on Suction Side of Pump
8.4 Extending a System to New Customers
Extent of Analysis
Elevation of Customers
Assessing an Existing System
Building onto an Existing Model
Skeletal Model of Existing System
Approximating a System as a Pump Source
8.5 Establishing Pressure Zones and Setting Tank Overflows
Establishing a New Pressure Zone
Laying Out New Pressure Zones
Tank Overflow Elevation
Tank Water Level Fluctuations
Tank Behavior During Emergencies
Multiple Tanks in a Pressure Zone
Regionalization
Tank Volume Considerations
Generating a System Head Curve
8.6 Developing System Head Curves for Pump Selection/Evaluation
8.7 Serving Lower Pressure Zones
PRV Feeding into a Dead-End Pressure Zone
Lower Zone with a Tank
Lower Zone Fed with Control Valves
Conditions Upstream of the PRV or Control Valve
8.8 Rehabilitation of Existing Systems
Data Collection
Modeling Existing Conditions
Overview of Alternatives
Replacement
Paralleling
Pipe Cleaning and Lining (Nonstructural Rehabilitation)
Sliplining (Structural Rehabilitation)
Pipe Bursting
Evaluation
8.9 Tradeoffs Between Energy and Capital Costs
8.10 Use of Models in the Design and Operation of Tanks
Systems Models
Computational Fluid Dynamics Models
Perspectives on System Design
8.11 Optimized Design and Rehabilitation Planning
Optimal Design Formulation
Rehabilitation Planning
Staged Development
Optimal Design Methods
Trial-and-Error Approach
Partial Enumeration Method
Linear Programming Methods
Nonlinear Programming Methods
Search Methods
Genetic Algorithms
Optimization Issues
Cost Data Implications
Reliability/Redundancy
Uncertainty in System Planning
Pipe Sizing Controlling Demands
Treatment of Pumps and Reservoirs
Multiple Objectives and the Treatment of the Design Optimization Problem
Multiobjective Decision-Making
Using Optimization
References
Discussion Topics and Problems
9. Modeling Customer Systems
9.1 Modeling Water Meters
9.2 Backflow Preventers
9.3 Representing the Utility's Portion of the Distribution System
9.4 Customer Demands
Commercial Demands for Proposed Systems
9.5 Sprinkler Design
Starting Point for Model
Sprinkler Hydraulics
Approximating Sprinkler Hydraulics
Piping Design
Fire Sprinklers
Sprinkler Pipe Sizing
Irrigation Sprinklers
Choosing the Right Sprinkler System
References
Discussion Topics and Problems
10. Operations
10.1 The Role of Models in Operations
10.2 Low Pressure Problems
Identifying the Problem
Modeling Low Pressures
Finding Closed Valves
Solving Low Pressure Problems
Leak Detection
10.3 Low Fire Flow Problems
Identifying the Problem
Solutions to Low Fire Flow
New Piping and Rehabilitation
Booster Pumping
Adding Storage
10.4 Adjusting Pressure Zone Boundaries
10.5 Taking a Tank Off-Line
Fire Flows
Low Demand Problems
10.6 Shutting Down a Section of the System
Representing a Shutdown
Simulating the Shutdown
10.7 Power Outages
Modeling Power Outages
Duration of an Outage
10.8 Power Consumption
Determining Pump Operating Points
Calculating Energy Costs
Multiple Distinct Operating Points
Continuously Varying Pump Flow
Developing a Curve Relating Flow to Efficiency
Variable-Speed Pumps
Using Pump Energy Data
Understanding Rate Structures
Optimal Pump Scheduling
Methods for Finding Optimal Pump Schedules
Steps for Optimizing Pump Scheduling
Extending Efficiency Curves
Pump Scheduling Optimization for the London Main Ring
10.9 Water Distribution System Flushing
Modeling Flushing
Representing a Flowed Hydrant
Estimating Hydrant Discharge Using Flow Emitters
Hydrant Location Relative to Nodes
Steady-State versus EPS Runs
Indicators of Successful Flushing
10.10 Sizing Distribution System Meters
Subsystem Metering
Using Models for Meter Sizing
Implications for Meter Selection
10.11 Models for Investigation of System Contamination
10.12 Leakage Control
10.13 Maintaining an Adequate Disinfectant Residual
Disinfectant Residual Assessment
Booster Chlorination
Mass Booster Source
Flow Paced Booster
Setpoint Booster
DBP Formation
Optimization Techniques
References
Discussion Topics and Problems
11. Water System Security
11.1 Water System Vulnerability
11.2 Potential Water Security Events
Physical Disruption
Contamination
Source Water Contamination
Contamination of Distribution System
Some Prominent Historic Events in Water System Security
11.3 Assessment of Vulnerability
Inspections and Checklists
Formal Assessment Tools and Methods
Fault Trees
Monte Carlo Simulation
Computer Simulation Models
Water System Vulnerability Checklist
SOURCE WATER
Wells
Surface Sources
Local Supplies
Alternate Emergency Sources Identified
Treatment
Storage
Distribution
PERSONNEL
SECURITY PATROLS
SAMPLING/DETECTION
11.4 Application of Simulation Models
Water Distribution System Models
Use as a Planning Model
Historical Modeling
Real-Time Modeling
Tank and Reservoir Mixing Models
Surface Water Hydraulic and Water Quality Models
A Checklist of Security Measures
SHORT TERM
LONG TERM
11.5 Security Measures
References
Discussion Topics and Problems
12. Integrating GIS and Hydraulic Modeling
12.1 GIS Fundamentals
Data Management
Geographic Data Models
12.2 Developing and Maintaining an Enterprise GIS
Keys to Successful Implementation
Needs Assessment
Design
Application Design
Database Design
Data Development Plan
Pilot Study
Production
Rollout
Case Study: Columbia, South Carolina
12.3 Model Construction
Model Sustainability and Maintenance
Communication Between GIS and Modeling Staff
Using an Existing GIS for Modeling
Network Components
Retrieval of Water Use Data
Node Service Polygons
Customer Meter Data
Area Flow Data
Land-Use/Population Data
Retrieval of Elevation Data
Modeling GIS Versus Enterprise GIS
Extract, Transform, Load
Modeling Features
12.4 GIS Analysis and Visualization
Using Attributes to Create Thematic Maps
Using the Spatial Coincidence of Features to Assign New Data
Using Spatial Relationships Between Features to Select Certain Elements and Assign New Data
Using Relationships to Trace Networks
Using Combinations of GIS Capabilities to Perform Complex Analyses
Case Study: Germantown, Tennessee
12.5 The Future of GIS and Hydraulic Modeling
References
Discussion Topics and Problems
13. Transients in Hydraulic Systems
13.1 Introduction to Transient Flow
Impacts of Transients
Overview of Transient Evaluation
13.2 Physics of Transient Flow
The Rigid Model
Limitations
The Elastic Model
Elasticity of a Liquid
Wave Propagation in a Liquid
Water Hammer Theory
Full Elastic Water Hammer Equations
History of Transient Analysis Methods
13.3 Magnitude and Speed of Transients
Characteristic Time
Joukowsky's Equation
Celerity and Pipe Elasticity
Comparing the Elastic and Rigid Models
Wave Reflection and Transmission
Attenuation and Packing
13.4 Numerical Model Calibration
13.5 Gathering Field Measurements
13.6 Transient Control
Piping System Design and Layout
Protection Devices
Pump Inertia
Air Chambers and Surge Tanks
One-Way Tank
Combined Devices
Pressure Relief and Other Regulating Valves
Booster Pump Bypass
13.7 Operational Considerations
Flow Control Stations
Automatic Control Valves
Check Valves
Air Release Valves
References
Discussion Topics and Problems
A. Units and Symbols
A.1 Units
A.2 Symbols
B. Conversion Factors
C. Tables
D. Model Optimization Techniques
D.1 Overview of Optimization
Optimization Terminology
Objective Function
Decision Variables
Constraints
The Optimization Process
Problem Visualization
Why Use Optimization?
D.2 How to Use Optimization
Single-Objective Optimization
Multiobjective Optimization
Applications of Optimization
Automated Calibration
Sampling Design for Calibration
Operational Optimization
Design/Expansion
Rehabilitation
D.3 Optimization Methods
Analytical Optimization
Linear Programming
Nonlinear Programming
Dynamic Programming
Nonadaptive Search Methods
Random Search
Hill-Climbing Strategies
Fibonacci Coordinate Search
Hooke and Jeeves Pattern Search
Downhill Simplex Search
Exploration and Exploitation
Adaptive Search Methods
Genetic Algorithms
Simulated Annealing
Ant-Colony Search
Tabu Search
D.4 Genetic Algorithms
D.5 Multiobjective Optimization
Weighting Method
Constraint Method
References
E. SCADA Basics
E.1 Components of a SCADA System
Field Data Interface Devices
Field Data Communications System
Bandwidth
SCADA Communications Availability and Protocols
Common Communications Media
Wide Area Network Backbone
Multiplexers
Local Networks
Communications Protocols
The Central Host Computer
Operator Workstation Communications System
Software Systems
E.2 Data Acquisition Mechanisms
E.3 Processing of Data from the Field
E.4 Levels of Control
E.5 Handling of Data During SCADA Failures
E.6 Errors and Accuracy Issues
References
Bibliography
General Water Distribution Hydraulics
General Hydraulic Modeling
Rehabilitation and Maintenance
Application of Models
Pumping
Customer Demands
Model Calibration
Optimization Techniques
Optimal Design
Modeling for Energy Efficiency
Water Quality Modeling
Fire Protection
Transients
Water System Security
SCADA
Geographic Information Systems (GIS)