Water resource engineering using EPANET

CEIE 440-540 – Homework

HW#09 Assignment

Assigned 24 Mar 2020. Due 31 Mar 2020 at start of class. Objective To analyze a water distribution, system using extended period simulation (EPS), to evaluate the ability of this system to support (1) a new Bottling Plant, and (2) a new Golf Course. You will: (a) analyze the existing system; (b) analyze the existing system with the addition of the two new demands, and (c) analyze a reinforced system that may be capable of supporting the new demand centers. Set-up (a) Schematic The layout of the existing distribution system is as shown: (b) System Physical Characteristics

The system mains are each 5,000-foot long, 8” diameter (C=100). (c) System Elevations

The elevations of the system are:

Point J-1 J-2 J-3 J-4 J-5 J-6 J-7 J-8 el.(ft) msl 150 145 110 125 140 100 130 75

(d) Well

The distribution system is served by a well from a water table 95-feet below the surface. When the pump is operating, the well has a 65-foot steady state drawdown with the pump set 10-feet beneath the water level. The well connects to the system at J-1 with a 12” diameter main (C=100). The well head (el = 0-ft msl) is located 1,200-ft from J-1 where it ties into the system.

J-1

J-5

J-6 J-8

J-4

J-3 J-2

J-7

CEIE 440/540 – Water Supply & Distribution HW#09 Assignment Page 2 (e) Well Pump

The well is served by a multi-stage, submersible pump that has the following pump characteristic curve and efficiency data:

Capacity (gpm) Head (ft) Shut-off 0 750 BEP 500 450 Max Flow 700 50

Pump efficiency = 86% Motor Efficiency = 92%

(f) Tank

A 110,160-gallon, cylindrical storage tank at an elevation of 220-ft and a 25-feet diameter, floats on the system at J-7. The tank is initially full.

(g) Demand There are four demand centers that can potentially be served by this system. They

include:

Existing Demands i. Frugalville located at (J-2) with a population of 3,200 and an average peak day

consumption of 85 gpd/c. ii. Happytown located at (J-6) with a population of 4,000 and an average peak day

consumption of 105 gpd/c.

Proposed Demands iii. Golf Course located at (J-8) that requires 300 gpm when irrigating. iv. Bottling Plant located at (J-3) that needs 150 gpm when operating.

(h) Pressure Ranges

Attempt to maintain a pressure range of 35 - 85 psi in the system with a minimum pressure of 20 psi.

CEIE 440/540 – Water Supply & Distribution HW#09 Assignment Page 3 (i) Demand Patterns The demand patterns for the four demand centers are as follows:

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0000 0.8 0.0 0.0 0100 0.7 0.0 0.0 0200 0.7 0.0 1.0 0300 0.6 0.0 1.0 0400 0.8 0.0 1.0 0500 0.9 0.0 1.0 0600 1.2 0.8 1.0 0700 1.4 1.0 0.0 0800 1.5 1.0 0.0

0900 1.2 1.0 0.0 1000 1.0 1.0 0.0 1100 0.8 1.0 0.0 1200 1.1 1.0 0.0 1300 1.0 1.0 0.0 1400 0.9 1.0 0.0 1500 0.9 1.0 0.0 1600 0.9 0.8 0.0 1700 1.2 0.0 0.0 1800 1.6 0.0 0.0 1900 1.4 0.0 0.0 2000 1.0 0.0 0.0 2100 1.2 0.0 0.0 2200 0.9 0.0 0.0 2300 0.8 0.0 0.0 2400 0.8 0.0 0.0

1. First EPS Analysis – The system initially has only one pump and distribution and no tank.

Impose only the existing residential demands from Frugalville and Happytown on the system and run an EPS analysis at 1-hour intervals for a 180-hour period.

Investigate how the system is operating by examining time-series graphs of key system parameters over the 180-hour period: (1) variation in system demand,1 (2) pump head2, (3) tank level (head), and (4) system pressures. Is this a satisfactory, sustainable system? (1a) Evaluate the system demands. How do they vary during the day? (1b) Evaluate the pump head. Is the system operating at the pumps BEP? If not, where is

it operating? (1c) Evaluate the system pressure variations by examining J-1, J-2, J-3, J-6, and J-8.

Describe the pressures in the system. 2. Second EPS Analysis – Add the tank to the system and rerun the EPS.

(2) Analyze the system now with a tank in place using the approach of your first analysis, but add the tank head (elevation of the water in the tank) to your analysis. Is this a satisfactory, sustainable system?

3. Third EPS Analysis – Add controls to the pump to turn it “off” when the tank level is almost

full (28-ft level) and turn the pump “on” when the tank is about half empty (3-ft level). Run an EPS analysis.

(3) Analyze the system now under control using by using the approach of the second

analysis. Is this a satisfactory, sustainable system?

1 Measure the system demand by looking at the flow rate in the pipe connecting the well pump to the

system. 2 Recall that EPANet reports pump head as a negative unit head loss. Therefore, you are going to see

negative head losses which are the same as positive head gains – the definition of a pump.

CEIE 440/540 – Water Supply & Distribution HW #5 Assignment Page 4 4. Fourth EPS Analysis – Add the golf course and bottling plant demands to the system and

rerun the EPS analysis.

(4) Analyze the system now under control and with the two new demands added. Is this a satisfactory, sustainable system?

5. Fifth EPS Analysis – To improve the system, you decide to add a second, identical pump,

also under tank level control. You decide if this pump should be added in series or parallel.

(5) Run a final analysis on the new system. Is this a satisfactory, sustainable system?

6. Cost – Determine the cost to run the each well pump for 24-hours, if the cost of electricity is $0.035/KWH.3

(a) What is the average Water Horsepower provided by each well pump? (Ans: 40.8 HP) (b) What Break Horsepower is required of the motor running each pump? (Ans: 47.5 HP) (c) What is the electrical power required to run each motor? (Ans: 38.5 KW) (d) What is the daily electrical energy required to run each pump? (Ans: 924.3 KWH) (e) What is the cost to operate this system each day? (Ans: $325)

3 You can transfer your hourly data from your hydraulic model to a spreadsheet and calculate the WHP

each hour. Then use the average hourly WHP to calculate the remainder of this question.