Lecture 4 - Water Pumping

Question 1

Water distribution systems are made up of networks of discrete components:

Answer 1

pipes, fittings, pumps, valves, and storage tanks

Question 2

Needed to determine the operating point of the pump?

Answer 2

A pump head-characteristic curve (H-Q curve of the pump)
and
system-head-capacity curve (H-Q curve of the piping system)

Question 3

Demand Considerations

Answer 3

1. By population, by survey of establishments
2. Per capita daily consumption
3. Demand Projections
4. Demand Fluctuations

Question 4

Price Elasticity of Water Demand

Answer 4

1. willingness of consumers or users to purchase
2. Demand vs. Requirement
3. willingness of consumers to give up water use in the face of rising prices, or conversely, the tendency to use more as price falls.

Question 5

high (price) = low (water demand) & high (revenue)

Answer 5

The use of price elasticity of water has been applied worldwide, and some important achievements have been made. The following schematic may depict the general trend of this principle

Question 6

If the price elasticity for water is -0.5%, what does this mean?

Answer 6

high avg. demand, high change in price

Question 7

What is WDS ?

Answer 7

Sir, tangina mo, pakyu

Question 8

gravity distribution

Answer 8

requires a reservoir at a sufficient elevation above the city so that water can reach any part of the distribution system with adequate pressure.

Question 9

tree-like distribution

Answer 9

system with many dead ends is unsatisfactory because water may become stagnant at the extremities of the system

Question 10

single main distribution

Answer 10

system is one in which a single main serves both sides of the street

Question 11

double main distribution

Answer 11

system there is a main on each side of the street.

Question 12

4 Types of WDS

Answer 12

gravity distribution
tree-like distribution
single main distribution
double main distribution

Question 13

residential districts Pressure Requirements

Answer 13

410 kPa at the hydrant are recommended for fire fighting

Question 14

commercial districts Pressure Requirements

Answer 14

minimum pressure of 520 kPa is tolerable, but higher pressures must be provided in districts with tall buildings

Question 15

fire departments use _____ to develop necessary fire pressure.

Answer 15

motor pumpers

Question 16

The maintenance of high pressure in mains means?

Answer 16

increased pumping cost and usually also increased leakage.

Question 17

domestic needs Faucet pressures

Answer 17

35 kPa are satisfactory

Question 18

a total pressure at the main should be? (Domestic)

Answer 18

240 KPa

Question 19

Elevated storage may be used advantageously for?

Answer 19

pressure stabilization

Question 20

Most surface reservoirs are covered to prevent contamination by?

Answer 20

animals, birds, and humans, and by shutting out sunlight, the growth of algae

Question 21

If topography does not permit sufficient head from a surface reservoir, a ____ may be used to gain necessary height

Answer 21

standpipe or elevated tank

Question 22

Water level fluctuation in standpipe is limited to?

Answer 22

10 meters

Question 23

Standpipes over _____ high are not recommended.

Answer 23

15 meters

Question 24

Minor distribution mains with fire hydrant in residential, business districts and street mains for domestic respectively.

Answer 24

> 150 mm
250 mm
50 mm

Question 25

___ at summits and ___ at low points.

Answer 25

Air relief valves, drain valves

Question 26

Gate valves should be not more than ___ apart

Answer 26

400 m

Question 27

Gate valves ___ are placed in manholes.

Answer 27

> 300 mm

Question 28

Smaller valves are accessible from the street through?

Answer 28

cast iron valve boxes

Question 29

Design of WDS (Descriptions))

Answer 29

1. Fire hydrants should be not more than 150 m apart to avoid excessive head loss in small diameter fire hose.
2. Preferably located at intersections
3. Flush hydrants to prevent interference with traffic.
4. Wall hydrants in commercial districts.
5. Post hydrants for easy location.
6. In cold climates, the valve is located below the ground.
7. A drain valve should be provided.

Question 30

The basic requirement of pipes in WDS are?

Answer 30

adequate strength and maximum corrosion resistance

Question 31

Planning Steps for WDS Development

Answer 31

1. Obtain data on, or estimate, the future population of the community, and study local conditions to determine the quality of water that must be provided. 2. Locate one or more sources of water of adequate quality. 3. Provide for the necessary storage of water, and design the works required to deliver the water from its source to community. 4. Determine the characteristics of water and establish water quality requirements. 5. Design water-treatment facilities. 6. Plan and design the distribution system, including distribution reservoirs, pumping stations, elevated storage, layout and size of mains and location of fire hydrants. 7. Provide for the establishment of an organization that will maintain and operate the supply, distribution and treatment facilities.