challenges in building water distribution models one...
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Challenges in Building Water Distribution Models one-to-one with GIS
Ben Chenevey, PE
Outline
Introduction
WDS Modeling Overview
Challenges w/ Building
Challenges w/ Updating
Summary & Conclusions
Outline
Introduction
WDS Modeling Overview
Challenges w/ Building
Challenges w/ Updating
Summary & Conclusions
What is a Distribution System Model?
Pipe
s
Junc
tions
Valv
es
Pum
ps
Tank
s
Res
ervo
irs
Hydraulic representation of actual system
Infrastructure Operations Demands
Evaluate Complex Hydraulics
• Seasonal demands
• Fire flow analysis• Main breaks• Surge analysis
Test Out Alternatives
• Operational changes
• Future service areas
Plan for Growth
• New demands• New supplies
Analyze Water Quality
• Tank cycling / mixing
• Water age• Chlorine residual
Summary of Model Uses
Annual Average Net Demand Within Water Distribution System
Advanced Modeling Applications
Improving capabilities change our questions
Advanced applications require advanced calibration
Advanced calibration requires advanced modeling expertise
Typical Demand Within A Zone/Through a Pumping
Station
Demand at this address
On this day of the year
Hydraulic Model Components
1st Step in Model Building• Latest available CAD/GIS maps for the
system• Provides Model Spatial Information &
Attributes
Model Often Changes After GIS Import• Facilities Modeling• Calibration
GIS & Modeling
One-To-One Modeling
Goal: Direct Link between GIS and
Model ID
Purpose: Improve Model Updates &
GIS Analytics
InfoWater• Modeling Software• Add-On for ESRI ArcGIS
GIS & Modeling
Infowater• GIS Gateway
GIS & Modeling
Introduction
WDS Modeling Overview
Challenges w/ Building
Challenges w/ Updating
Summary & Conclusions
Outline
Challenges w/ Building Models One-to-One
1 All GIS is Different (YMMV)
2 Planning is Key
3 Interaction between GIS & the Model
4 100% is Rarely Achieved
Example Challenges - Connectivity
Extent of WDS in GIS
• Pipes, Valves, Fixtures, Appurtenances
• Topology of Layers
Model Connectivity
• Pipes - Junctions• Fill Connectivity• Orphan Pipes & Nodes
Example Challenges - Connectivity
Model has different & advanced requirements
GIS deficiencies often found during model build
Can be hard to find
• Network Traces
How to account for
• Fix GIS• Add new Pipes in
Model
Pipe not split by cross connections
Example Challenges - Facilities
Pump Stations often represented as point in GIS• May be connected or end at building• Expanded to include interior piping and pumps in the model
GIS Representation Model Representation
Example Challenges - Facilities
Even if captured in GIS, Models need additional information• Pumps & Valves• Minor Loses• Operational Controls• Closed Valves• Calibration
Outline
Introduction
WDS Modeling Overview
Challenges w/ Building
Challenges w/ Updating
Summary & Conclusions
Challenges w/ Updating Models
1 Continuous Model Updates
2 Keep Same Conventions as Original Build
3 Has Model Influenced GIS?
4 Updated Model vs. New Model
Example Challenges – Updating Models
New PipesCreating
New Records
Replaced Pipes or New Information
Update Existing Records
Abandon Pipes
Delete Non-Matching (?)
GIS Attribute
Large West Coast Utility• Update a One-to-One Model w/ Latest GIS• Use GIS Exchange Wisely
Example Challenges – Zone Based UpdatesLarge Midwest Utility• Converting to One-to-One with GIS is possible• For active model, Zone based upgrade may be ideal
Isolate Zone
• Select Zone Layers
• Delete from Model
Update Zone
• Import from GIS
• Follow a Routine
Finalize• Boundaries• Facilities• Calibrate
Example Challenges – Retroactive Alignment
Model was spatially inconsistent
No impact on Hydraulics
Asset Management Team wanted model results
GIS – Model Link Identified
GIS Spatial Information Updated in
Model
Previous Model Layout vs GIS
Updated Model Layout vs GIS
Flint, Michigan• Hydraulic Modeling Project• Asset Management Project
Outline
Introduction
WDS Modeling Overview
Challenges w/ Building
Challenges w/ Updating
Summary & Conclusions
Summary / Takeaways
• Improve Model Update Frequency and Level of Effort• Help get Model Results into GIS
Model that is One-to-One with GIS can:
• Usually 100% (but that’s ok!)
Model that is One-to-One is NOT:
• Consider the specific GIS (YMMV)• Create & Follow a Plan during model build
Proper Implementation Requires to:
• Understand how new or revised elements will be handled during model build• Incremental Updates for Models are possible
Model Updates create unique challenges:
