water distribution planning
DESCRIPTION
Presented at the Ohio AWWA SW District Meeting.TRANSCRIPT
Water Distribution System Planning
Dan Barr, PE and Mark Upite, PEBurgess & Niple, Inc.
Dan Barr, PE and Mark Upite, PEBurgess & Niple, Inc.
Ohio AWWA SW District Meeting
Friday, Oct. 14, 2011
Introduction
• Do I have any problems in my system?• How do I know what’s not working?• How complete is my mapping?• Are main breaks a problem?• What is adequate storage? • How do I know what to replace first?
You need a plan!
• Do I have any problems in my system?• How do I know what’s not working?• How complete is my mapping?• Are main breaks a problem?• What is adequate storage? • How do I know what to replace first?
You need a plan!
Information Required for Planning
• Piping Network- GIS, CAD, Hard Copy
• Customer Demands- GIS, Evenly distributed, Billing Records with Address
Locater in Esri’s ArcMap (Geocoding)
• Ground Elevations- GIS, LIDAR, USGS 7.5 Min Map
• Pump, Control Valve, and Tank Information- Pump Curves, Valve Type/Status, Tank
Geometry/Elevations
• Piping Network- GIS, CAD, Hard Copy
• Customer Demands- GIS, Evenly distributed, Billing Records with Address
Locater in Esri’s ArcMap (Geocoding)
• Ground Elevations- GIS, LIDAR, USGS 7.5 Min Map
• Pump, Control Valve, and Tank Information- Pump Curves, Valve Type/Status, Tank
Geometry/Elevations
Additional Information for Planning
• Population Forecasts• Hydrant Data• Isolation Valve Data• Customer Meter Locations
• Population Forecasts• Hydrant Data• Isolation Valve Data• Customer Meter Locations
Model Benefits
The best plans start with a water distribution system model.
• A model is a computer simulation of the system.• Predicts pressure and flows under varying
conditions.• Can determine what the existing and future needs
are to optimize system performance.
Model Creation and Data Entry
Insert Pipes, Contours/Surface, Background MappingClean Up Junctions, Verify Cross Connections, Assign Elevations
Geospatially Locating Demands
- Incorporate GIS Meter Locations or Utilize Geocoding to Develop Locations- Use Billing Records to Apply ADD to Meter Location- Allocate Meter Location and Values to Nearest Junction - Evenly Distribute Unaccounted For Losses
Global Edit Demands
- Now a ADD Scenario is Setup, Create Scenarios for MDD and PHD- Typical MDD is 1.5 X ADD- Typical PHD = 2 X MDD- Use Historic WTP Production or Master Meter Records if Available- Modify Pumps/Booster Pumps/Tank Levels/etc.
Calibration & Fire Flow Tests
Field Data is Needed to Calibrate the Model.
Model Update – Darwin Calibrator
- Field Data is Compared Against Model Output- Algorithms are Run Millions of Times and Pipe Friction is Adjusted for Each Pipe Until Field Data and Model Output Converge.
Model Update – Calibration
The City should be able to trust the model with million dollar waterline decisions!
Decisions made with the model can save a City millions!
The City should be able to trust the model with million dollar waterline decisions!
Decisions made with the model can save a City millions!
Transmission Evaluation
AWWA Guidelines
Meet Performance Standards
Determine Design Conditions
AWWA Guidelines
Meet Performance Standards
Determine Design Conditions
Extended Period Simulations
Flow patterns / reversal
Chemical assessments
Storage Tank turnover
Flow patterns / reversal
Chemical assessments
Storage Tank turnover
Technical Approach – Chemical Assessments and Tank Turnover
Look at Water Age First for Water Quality Issues
Fire Flow Capacity Evaluations
Fire Flow Capacities and Durations will be Dependent Upon:
Insurance Insurance Service Office (ISO), Factory Mutual Insurance Company (FM Global)
Local Code Building and Zoning
Local Authority (Has power to supersede both above) Fire Chief/Fire Marshall
Insurance Insurance Service Office (ISO), Factory Mutual Insurance Company (FM Global)
Local Code Building and Zoning
Local Authority (Has power to supersede both above) Fire Chief/Fire Marshall
Example of Residential Fire Flow Trouble Spot and Evaluation of Cost Effective Solution :
Exist fire flows meet insurance and local code. However, the Fire Marshall wants all hydrants in a particular residential area to have a minimum of 1,000 gpm at max day demand while maintaining 20 psi residual pressure.
Exist fire flows meet insurance and local code. However, the Fire Marshall wants all hydrants in a particular residential area to have a minimum of 1,000 gpm at max day demand while maintaining 20 psi residual pressure.
Projects Evaluated to Increase Fire Flows
Project Costs and Modeled Fire Flow Results
Color Coded Fire Flows Allow Identification of Trouble Spots and Results of Solutions
CIP Summary & Location Plan
Storage Analysis
A comprehensive, innovative, and straightforward storage and pumping analysis that will help determine:
Distribution system capabilities during critical conditions
Current and future storage/pumping requirements Determine and test proposed solutions District by district requirements Combines many storage concepts into one analysis. Incorporates minimum turnover requirements No mysterious factors or multipliers
A comprehensive, innovative, and straightforward storage and pumping analysis that will help determine:
Distribution system capabilities during critical conditions
Current and future storage/pumping requirements Determine and test proposed solutions District by district requirements Combines many storage concepts into one analysis. Incorporates minimum turnover requirements No mysterious factors or multipliers
Storage Evaluation Spreadsheet
Distribution System Storage Requirements
Criteria (unit) Sample District
YourDistrict 1
YourDistrict 2
YourDistrict 3
YourDistrict 4
YourDistrict 5
Average daily demands (gpm) 100
Peak day demands (gpm) 200
Peak hour demands (gpm) 300
Booster pump firm capacity (gpm) 200
Design fire flow (gpm) 3,500
Design fire duration (hours) 3
Design fire flow supplied by storage (gpm) 3,500 0 0 0 0 0
Total fire flow storage capacity required (gal) 630,000 0 0 0 0 0
Balancing storage required (gal) 48,000 0 0 0 0 0
Desired emergency outage duration (hours) 6
Emergency outage required capacity assuming average daily demands (gal) 36,000 0 0 0 0 0
SubtotalRequired storage capacity (gal)
630,000 0 0 0 0 0
Desired turnover percentage 20% 20% 20% 20% 20% 20%
Required storage volume for desired turnover (gal) 126,000 0 0 0 0 0
Total additional capacity required for turnover (gal) 78,000 0 0 0 0 0
TotalRequired storage capacity
708,000 0 0 0 0 0
Current storage capacity (gal) 1,000,000
Difference (gal)Deficiencies will display in red
292,000 0 0 0 0 0
Maximum sustainable storage capacity (gal) 720,000 0 0 0 0 0
Analysis Components
This analysis determines the minimum required storage volume for each of the following components:
Operational (balancing and turnover)
Fire Protection Outages
This analysis determines the minimum required storage volume for each of the following components:
Operational (balancing and turnover)
Fire Protection Outages
The Three Components of Storage
The Three Components of Storage
Analysis Data Requirements
Water demands by district is ideal Existing system storage volumes Existing pumping capacity
Water demands by district is ideal Existing system storage volumes Existing pumping capacity
Emergency Outages
This component deals with situations when the source(s) for each district is out of service. Assumptions for determining minimum outage
volume:– The minimum number of hours the system must operate on
storage alone– The demands during the outage
The system’s emergency management plan must coordinate with these assumptions
This component deals with situations when the source(s) for each district is out of service. Assumptions for determining minimum outage
volume:– The minimum number of hours the system must operate on
storage alone– The demands during the outage
The system’s emergency management plan must coordinate with these assumptions
Emergency Outage Equations
Minimum Storage Volume Demand (gpm) x Outage Requirement (hours) x
60 (minutes/hour) = Required Volume (gal)
In Millions of Gallons Per Day Demand (mgd) x 1,000,000 gal/mil gal x Outage
Requirement (hours) / 24 (days/hours) = Required Volume (gal)
Minimum Storage Volume Demand (gpm) x Outage Requirement (hours) x
60 (minutes/hour) = Required Volume (gal)
In Millions of Gallons Per Day Demand (mgd) x 1,000,000 gal/mil gal x Outage
Requirement (hours) / 24 (days/hours) = Required Volume (gal)
Fire Protection
This component is sized by determining the design fire in each district.
The design fire is an assumption based on a number of factors– Local fire department requirements– Organizations like ISO, Inc. that publish public fire protection data– Ohio Fire Code
Begin analysis after choosing design fire – How much of required fire flow rate can be delivered by system
pumping– What portion of the design fire will need to be delivered by system
storage
This component is sized by determining the design fire in each district.
The design fire is an assumption based on a number of factors– Local fire department requirements– Organizations like ISO, Inc. that publish public fire protection data– Ohio Fire Code
Begin analysis after choosing design fire – How much of required fire flow rate can be delivered by system
pumping– What portion of the design fire will need to be delivered by system
storage
Fire Protection Equations
Capacity Available for Fire Protection Firm Pumping Capacity (gpm) – Maximum Day
Demands (gpm) = Pumping Capacity available for fire protection (gpm)
Required System Storage [Design Fire Flow Rate (gpm) – Available Pumping
Capacity (gpm)] x [Design Fire Duration (hours)] x (60 minutes/hour) = Required System Storage (gal)
Capacity Available for Fire Protection Firm Pumping Capacity (gpm) – Maximum Day
Demands (gpm) = Pumping Capacity available for fire protection (gpm)
Required System Storage [Design Fire Flow Rate (gpm) – Available Pumping
Capacity (gpm)] x [Design Fire Duration (hours)] x (60 minutes/hour) = Required System Storage (gal)
Operational Storage
This component includes storage volume utilized for: Daily turnover of the tank
– Tank turnover is used to keep stored water fresh Current industry practice and the Ohio EPA’s recommendation:
- Turnover 20% to 40% of the tank every day
Maximum hour balancing– Storage required to supply demands over the system’s
pumping capacity
This component includes storage volume utilized for: Daily turnover of the tank
– Tank turnover is used to keep stored water fresh Current industry practice and the Ohio EPA’s recommendation:
- Turnover 20% to 40% of the tank every day
Maximum hour balancing– Storage required to supply demands over the system’s
pumping capacity
Operational Equations
TurnoverStorage Volume (gal) x Turnover Target
Percentage (%) = Required System Storage (gal)
BalancingMaximum Hour Demand (gpm) – System Pumping
Capacity (gpm)] x 8 hours x 60 (minutes/hour) = Required System Storage (gal)
TurnoverStorage Volume (gal) x Turnover Target
Percentage (%) = Required System Storage (gal)
BalancingMaximum Hour Demand (gpm) – System Pumping
Capacity (gpm)] x 8 hours x 60 (minutes/hour) = Required System Storage (gal)
Total Required Storage Volume Per District
After calculating the three component volumes (emergency outage, fire protection and operational storage) determine the total required volume by: Adding all three components Adding operational component to the larger of the two volumes
for outage and fire protection Sizing the required tankage on the largest of the three
components
Final parameter: Determine if the district has enough average daily demand to
turn over the required storage
After calculating the three component volumes (emergency outage, fire protection and operational storage) determine the total required volume by: Adding all three components Adding operational component to the larger of the two volumes
for outage and fire protection Sizing the required tankage on the largest of the three
components
Final parameter: Determine if the district has enough average daily demand to
turn over the required storage
Maximum Sustainable Storage
• (5)x(average daily demand) = Maximum Sustainable Storage for 20% turnover.
• (4)x(average daily demand) = Maximum Sustainable Storage for 25% turnover.
• (5)x(average daily demand) = Maximum Sustainable Storage for 20% turnover.
• (4)x(average daily demand) = Maximum Sustainable Storage for 25% turnover.
Final Steps
Determine remedies for deficiencies discovered during the process. Problems can be solved by a combination of:
– Increased pumping capacity May solve fire flow problem economically Power or mechanical failures could occur
Increased storage volume– Increases emergency outage capacity without fear of
mechanical or power-related failures– Expensive, might have siting issues
Reduced demands– Usually not possible unless customers can be shifted to
another neighboring pressure district
Determine remedies for deficiencies discovered during the process. Problems can be solved by a combination of:
– Increased pumping capacity May solve fire flow problem economically Power or mechanical failures could occur
Increased storage volume– Increases emergency outage capacity without fear of
mechanical or power-related failures– Expensive, might have siting issues
Reduced demands– Usually not possible unless customers can be shifted to
another neighboring pressure district
Common Situations
Too much storage
Too little storage
Storage in the wrong place
Too much storage
Too little storage
Storage in the wrong place
Asset Management
Manage assets based on weighted parameters:
• Age• Material• Criticality• Capacity• Service History• Pavement Plan
Manage assets based on weighted parameters:
• Age• Material• Criticality• Capacity• Service History• Pavement Plan
Conclusion and Summary
• Planning is key for current and future system infrastructure.• Data is required.• Model will prioritize capital improvements.• Proper sizing of storage is vital for proper operation
and avoiding further issues.• Asset Management is key to maximize infrastructure
life-cycle.
• Planning is key for current and future system infrastructure.• Data is required.• Model will prioritize capital improvements.• Proper sizing of storage is vital for proper operation
and avoiding further issues.• Asset Management is key to maximize infrastructure
life-cycle.
Conclusion and Summary
Any Questions?Any Questions?