1. CE 3372 Water Systems Design
Lecture 10 –Network Models in EPA-NET

2. Overview Water Distribution System Components EPA-NET Workshop Pumps
Valves
EPA-NET Workshop

3. Head Head is energy per unit weight of water
Energy = Kinetic + Potential Energy
= Velocity + (Elevation + Pressure)
EGL = Total head at point in the system
Whoever thinks they can answer it, will get 10 pts.
Not arbitrary term, or an elevation term even though units are feet.
It’s energy required to move water. Water that’s static has pressure and elevation.
Water bottle drop with knife, elevation vs ceiling (ex: res with 5ft elevation and 10 ft elevation)

4. Piezometer measure the pressure in the system at specific point
Pitot measures the pressure and velocity in the system at specific
Note: EGL and HGL are at the same at the reservoirs because of velocity.
EGL. When water is rushing out the velocity of the water in the system increases quickly

5. How to select a Pump A quick overview
Step 1 – Place system curves on chart (new and old)
Step 2 – Select flow range (design requirements)
High end = Peak flow + fire
Low = Avg. daily
Step 3 – Narrow down pumps based on operating point
Step 4 – Check Efficiency! (75% +) and Select Pump
Step 5 – If below 75%, try again with new Pump Curves

6. System Curve when OLD System Curve at NEW standards
Old it takes MORE head to produce same amount of flow
Step 1 – Place System Curves (new and old on there)
Step 2 – Select Flow range you need to operate on (Design req.)
High end = Peak flow + fire
Low = Avg daily
Range can factor as much as twice
Step 3 – Narrow down pumps based on operating point
7.25 is NOT going to work
Step 4 – Look at efficiency!!! (75% +)
System Curve at
NEW standards

7. Pump and System Curves
Pump Curve – How much energy the pump delivers to the water
System Curve – How much energy it takes to deliver a flow rate to everyone in your distribution
System, more flow rate, more resistance, needs more head (energy)
Pump, more flow rate, can’t push up as far, head goes down.
Because Pumps are producing head. System is not.

8. Valves

9. Valves
Devices which control amount and direction of fluid flow in closed conduit systems
Bronze, brass, iron, or steel alloy

10. Types of Valves
Stop Valves – Used to completely/partially shut off flow of fluid
(ex: globe, butterfly, gate, plug, needle)
Check Valves – Used to permit flow in only one direction
(ex: ball-check, swing-check, lift-check)
Special Valves
relief, pressure-reducing, remote-operated
Globe is most used.

11. Globe Valve
Disc attached to valve stem rests against seat to shut off flow of fluid

12. Gate Valve

13. Butterfly Valve
Used in water. Fuel and ventilation systems

14. Valves in EPANET Valves are links Input Parameters Output Parameters
Limit pressure of flow at a specific point in the network
Input Parameters
Start and end nodes
Diameter
Setting
Status
Output Parameters
Flow rate and headloss

15. EPA-NET Workshop

16. Review In EPANET: valves are (links or nodes)?
pumps are (links or nodes)?
pipes are (links or nodes)?
reservoirs are (links or nodes)?
demands are supplied at (links or nodes)?
what is meaning of negative demand?
where are elevations specified?
how is pump performance specified?

17. Step-by-Step Example

18. EPANET Example
Network Layout

19. EPANET Example
Demands