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close this book Water purification, distribution and sewage disposal for Peace Corps volunteers
close this folder Section 3: Planning the distribution system
View the document Overview:
View the document Design
View the document Existing facilities
View the document Size and nature of the community
View the document System capacity
View the document Water source
View the document Proposed system
View the document Financing the project
View the document Lesson plans

Section 3: Planning the distribution system

 

Overview:

A water distribution system is a large project requiring great expense in time and capital. The health of the community will be affected by the results of the project. The planning of the project is necessarily of great importance, so as to ensure an economic, efficient, and safe result.

The trainee must be aware of the effects that the existing facilities, the community, the material and financial requirements, impose upon the plans he must prepare prior to the start of the project, This section covers these basic requirements of the planning for a water distribution system.

SECTION 3: WATER DISTRIBUTION SYSTEMS

A. PLANNING THE DISTRIBUTION SYSTEMS

OBJECTIVE: Develop a plan for a distribution system which will meet the requirements of the given community, utilizing the existing and proposed facilities.

TASKS:

1. Assemble a list of existing man-made facilities and potential water sources.

2. Determine average demand; peak demand and when it occurs; and the capacity of the system required to meet both the present and projected requirements of the community.

3. List the components and characteristics of the proposed system. These include:

a. Water source.

b. Pumping equipment - type of pump

c. Capacity of distributing reservoir or storage

d. Location of distributing reservoir with relation to service connections.

e. Source of energy used in the system

f. Pipe sizes and pipe laying system

4. Choose the most economical and practical source from among existing and proposed sources, with the following characteristics:

a. Supplies required quantity

b. Requires no treatment or very simple treatment

c. System easily installed

d. Located in such a position that gravity can be used as supply energy.

5. Choose most suitable site for the system facilities. Choice guided by:

a. Proximity to and accessibility from residence

b. Safety from contamination

c. Safety from destruction

d. Availability of room for future expansion

6. Estimate the expected cost of construction, operation and maintenance of the whole system.

7. Identify the source of finance, amount to be financed and conditions related to the transaction.

FUNCTIONAL SKILLS:

1. Classify type of water sources

2. Measure the yield of different water sources.

3. Draw topographic map. Estimate distance and scale this on a sketched map.

4. Classify climatic types and state construction precautions, e.g., Tropical: heavy rain, insect pests, etc.

5. Recognize useful local materials which can be used instead of a relatively expensive imported one, e.g. bamboo pipes.

6. Calculate projected population.

7. Calculate the capacity of a storage tank from data on population and rate of individual consumption.

8. State factors which determine and guide the selection of pumping equipment.

9. Recognize conditions which make a distribution reservoir a necessity.

10. Decide what traditions can be changed without much social discontent and which must be contended with.

11. Prepare a chart projecting expected costs of materials and labor, and estimate the required amount of money.

TERMINAL PERFORMANCE TESTS:

1. In a field exercise:

a. Classify and measure yield of various water sources which exist in the area.

b. Describe the rest of the existing facilities.

c. Sketch the system on a labeled map of the area.

d. Classify climatic types.

e. List all local materials which can be used to improve the system.

2. In a given community:

a. Estimate the present, and project the future population.

b. Determine average dally demand, the peak demand and when it occurs.

c. Calculate the capacity required by the population.

3. From among many sources in the area, choose the best one to develop, and Justify.

4. Estimate the cost of establishing the proposed system, and prepare a plan for financing that would be feasible in a local village environment.

 

Design

WATER DISTRIBUTION SYSTEMS

PLANNING THE DISTRIBUTION SYSTEM

One of the most difficult and baffling problems in the planning of a small water-supply system for a rural community is the lack of criteria upon which a design can be based. The volunteer needs answers to such questions as: "What increase should be allowed for future population growth?") "Should provision be made for periods of peak demand?"; and "What about storage?" Such technical questions have been thoroughly studied and standardized in textbooks dealing with design of water supplies for urban communities. However, for most rural, underdeveloped areas of the world, reliable design guides have not yet been established. Furthermore, certain elements of design are matters for local decision, depending on geography, local economy, custom, and other factors.

The experience gathered from several rural water-supply programs has been analyzed and is summarized below to serve only as a broad guide. It is realized that there are wide variations in water-supply practice throughout the world and that every designer should not apply blindly the criteria listed here; instead, you should be able to make a critical analysis of the conditions and problems of the area under study and should develop applicable criteria. In so doing, you should contact the health administration of the area concerned with a view to consulting the minimum standards for design and construction which this administration may have issued through its public health engineering division.

There is, however, general agreement on the following fundamental point; in the design of rural water-supply systems, primary consideration should be given to the protection of the quality of the natural water selected, since treatment should be considered only as the very last resort. This requires the incorporation in the design of necessary sanitary safeguards, beginning with the proper location of intake structures and pipes. Except, in unusual circumstances, other engineering and structural elements should be conceived around this need.

Before beginning the actual construction of a village water system, a well defined plan needs to be drawn. The water system, when completed, will be the result of a large commitment from all the local people, both in finances and labor. To be sure that the system is what they want and need, careful planning is a requisite. In planning the water distribution system, there are seven major categories to be defined.

1. Existing Facilities: What already exists? How good is it? Can it be made part of the overall system?

2. Size and Nature of the Community? How many people will be users? How are they distributed? What customs or traditions do they have that must be considered in the overall plan?

3 System Capacity: How much water is needed dally? When are the peak demands?

4. Water Source: What type of source will provide the most economical and satisfactory water for the system?

5. Proposed System: Location of facilities, pipes, outlets, etc.

6. Site of Proposed Facilities: An outgrowth of the proposed system, What problems will there be in obtaining the land needed for the proposed facilities?

7. Financing: How will the materials be obtained? Will this project be financed by government, cooperatives, on a cost basis, etc.?

 

Existing facilities

From data collected in Section I, you have already quite fully analyzed the types of sources available, and evaluated each as a potential water source for a water system. How you need to concentrate on matching the sources of water to the existing community. This is accomplished by:

1. Adding to the topographical map already started, the distribution of the users in the community.

2. Considering local customs and traditions regarding water uses, and needs.

3. From (2) above, calculating system capacity requirements, and system proposals to satisfy those requirements.

 

Size and nature of the community

The proposed water system has to be built around the customs and traditions of the community it will be serving. For example, if the social patterns of the community are built around family structures, the system should strive to provide sources of water to families, and not to the community through centrally located water distribution facilities..

In many developing countries there are some traditions which appear "primitive" to western culture. for example, in most parts of Africa, men swim upstream, and women downstream. Or men first, then women. In Moslem countries women do not appear in public unveiled. For an outsider, Peace Corps are outsiders, to institute an acceptable new system in such areas, he has to study very carefully all such traditions and then modify his system to suit the community. If he cannot adjust the system, he should try to get his point across by explaining to the people (or their representatives) why it is important that he interferes with their life. For example: in the Moslem community cited, the best plan would be to distribute water into houses instead of establishing public wells. It must be emphasized that in order to establish the most effective plan, a thorough study of the community must be done by the planner. Usually a discussion with the local authorities will yield a good result. Remember, when help is imposed from above, it meets with resentment and failure.

In describing the community, care should be taken to determine population, both present and projected.

Population growth is determined by:

1. Future economic developments in the community.

2. The character and location of the community in relation to other population centers.

3. The presence or possible introduction of small industries into and around the community (the installation of water scheme itself will cause population growth.)

A common acceptable estimate for future population growth in most rural areas is a 50% increase in population over a ten year period, or approximately 5% per year. This should be the minimum figure upon which the rural water-supply design should be based.

If this estimate appears too high for a particular situation, the system should be designed for present population in a way as to allow for future expansion.

Example on projecting population:

Original population

100,000

Increase over 10 year period 50%

50,000

Projected population in 10 years

150,000

Relationship between population and storage capacity:

The required capacity for a storage tank equals half the total daily water requirement.

Total daily water requirement = average demand x population + larger users.

(Large users would include public centers, schools and factories. If these are not in the community, then the last term is left out)

Storage Capacity = 1/2 [average demand x design population + large users]

 

System capacity

The methods for evaluating each type as a potential water system source was covered in Section I. For each source you will have to determine its yield. This is the maximum quantity of water that can be drawn from a source in a given period of time. To calculate the yield for a source of water you:

1. Draw a measured quantity of water from the source;

2. Time how long it takes the source to replenish the drawn quantity)

3. Divide the amount of water drawn by the time taken to refill.

Yield is usually stated in gallons per minute. Below are examples for estimating yield for various types of water sources.


Fig. 24 Cistern Catchment Yield

a. Cistern Catchment Yield

To estimate your catchment area, the minimum yearly rainfall and the amount of water required by the family during one year, must be estimated. Sometimes, the government meteorological section can give you the minimum rainfall expected. If they do not, you can estimate the minimum rainfall at two-thirds of the yearly average. Take the average amount of water needed by the family for one day and multiply it be 365 to learn how much is needed for one year. Then use the chart to find how much roofspace is needed (Fig. 24 )... Suppose you have a rainfall of 60 inches a year and the family needs 20 gallons a day, then...

2/3 x 60 equals a minimum rainfall of 40 inches a year

365 days x 20 gallons a day equals 7300 gallons a year

The chart shows that a catchment area of about 300 square feet is needed to supply the family with enough water for one year.

b. Yield of Small Streams

This is a rough but very rapid method of estimating water flow for small streams. The number of streams that must be used and the flow variations are important factors in determining the necessary facilities for utilizing the water. Here is a way to survey a water supply problem quickly by allowing you to take rapid flow measurements.

The equation for stream flow is - - Q = K x A x V

Q = flow in gallons per minute (8.33 pounds = l gallon)

A = cross section of stream, perpendicular to flow, in square feet.

V = stream velocity, feet per minute.

K = a corrected conversion factor since surface flow is normally slower than average flow. For normal stages use K = 6.4; for flood stages use K = 6.7 to 7.1.


Fig. 25 Determine Stream Yield


Fig. 26 Cross Section of Stream

To find "A"... the stream will probably have different depths along its length so select a place where the depth of the stream is average...take a measuring stick and place it upright in the water about one foot from the bank...note the depth of water...move the stick two feet from the bank in a line directly across the stream...note the depth...move the stick three feet from the bank, note the depth, and continue moving it at one-foot lengths until you cross the stream. Draw a grid, like the one above, and mark the varying depths on it so that a cross-section of the stream is shown. A scale of one inch equals one foot is often used for such grids. By counting the grid squares and fractions of squares, the area of the water can be estimated. For example, the grid shown here has about 15 square feet of water.

To find "V"...put a float in the stream and measure the distance of travel in one minute (or fraction of a minute, if necessary.) The width of the stream should be as constant as possible and free of rapids, when measuring the velocity.

Example:

Cross section is 15 square feet.

Velocity of float = 20 feet traveled in 1/2 minute

Stream flow is normal

Q = 6.4 X 15 x 20 feet/.5 minute

3800 gallons a minute

 

 

Water source

Factors to be considered in the selection of a water source include the following:

a. Purity of the source.

b. Proximity of the source to the community

c. Altitude of source above service connections

d. Temperature variations of water from the source.

Guide to choosing a source:

a. First choice, a source that

- requires no treatment

- uses gravity for distribution energy

- requires minimum maintenance

- is cheap to develop

- e.g. springs

b. Second choice, that which

- requires no treatment

- but must be pumped out and into the supply lines.

- e.g. wells.

c. Third choice, that which

- requires simple treatment

-uses gravity for distribution energy

- e.g. catchment cisterns.

d. Fourth choice, that which

- requires simple treatment

- must be pumped

- e.g. rivers

 

Proposed system

SELECTING SITES FOR THE SYSTEM'S FACILITIES

1. Source - must be near to the community (see above).

2. Pump station

- should be above the highest probable flood level; or be suitably protected against flood.

- should be accessible at all times

- should be large enough to meet future expansion.

- should have suitable topography

- should be well protected from possible sabotage-e.g. by enclosing it within an industrial type wire fence with a locked gate.

3. Storage Tanks

- should be centrally located

- if possible, should be put on the highest ground in the area.

PUMP SELECTION

The most important considerations in selecting a pump are:

1. The skill of the operators and maintenance men available

2. The initial cost of pump and driving equipment

3. The cost of operation and maintenance

4. The capacity and lift required

5. Availability of power to operate the pump

6. The sanitary features of the pumps available commercially.

7. Type of source in which the pump is to be installed; including the depth of static water level from ground surface.

8. Reliability of equipment, and availability of spare parts.

The following is a general guide to the selection of pumps for rural water-supply systems:

1. Structure of the pump

a. All movable parts above ground and easily accessible are easy to maintain. Suitable for areas with no skilled maintenance man.

b. If skilled maintenance men are available, first choice should be pumps with submerged cylinders.

2. Type of power available; Power-driven pumps must be of high efficiency to reduce the cost of power.

3. Design of the pump: The pump design should be flexible enough to be used in a wide range of sources. There are some pumps which must operate under the conditions for which they were designed, e.g. deep-well turbine and centrifugal pumps.

4. Repairs: The selected pump must be of a type for which repair and replacement parts are easily obtainable.

5. Sanitary Standards: The pump and equipment must be constructed as to prevent contamination of water either at source or enroute to storage. Specific sanitary conditions to be considered:

a. Pump head should be designed to prevent contamination from environment from reaching the water-chamber of the pump

b. The base should be waterproof.

c. The pump should not need priming

Information required when ordering or inquiring about a pump.

1. The inside diameter of hole or casing in which the pump is to be installed.

2. The static level of water in well, measured from ground level.

3. The desired output in gallons per minute.

TABLE: 5: ADVANTAGES AND DISADVANTAGES OF VARIOUS TYPES OF PUMPS

 

POSITIVE DISPLACEMENT

VELOCITY

Types pumps

hand plunger type

motor, wind driven, plunger type

chain or continuous bucket

centrifugal

deep-well turbine

jet

Usual well pumping depth (ft)

22-25 ft shallow well; up to 600 deep well

22-25 ft shallow well; up to 600 deep well

Depends on valve being lifted and type of power

10-20 ft

50-300 ft

15-20 ft below ejector

Capacity Gallons/Minute

3-15

10-25

4-20

Very wide range: 2 to unlimited

Very wide range: 25-5,000

5-125

Efficiency range (%)

Low; can be improved with double-acting cylinders; 25%-60%

Low; can be improved with double-acting cylinders; 25%-60%

Low

Good: 50%-85%

Good: 65-80%

Low: 40%-60%

Operation

Very Simple

Simple

Very Simple

Simple

More difficult; needs attention

Simple; air locks can cause trouble

Maintenance

Simple, but valves and plunger require attention; more difficult when pump cylinder is in the well

Same as hand pump; maintenance of motors sometimes difficult in rural areas

Simple

Simple, but attention is necessary

More difficult and constant; skilled attention is necessary

Simple, but attention is necessary

Cost

Low, but higher when cylinder is in the well

Low, but higher when cylinder is in the well

Reasonable

Reasonable

Higher, especially in deep wells

Reasonable

Types of pumps

hand pumps, plunger type

motor, wind driven, plunger type

chain or continuos bucket

centrifugal

deep-well turbine

jet

Power

Hand or animal

Wind, motor

Hand, animal, wind motor

Motor

Motor

Motor

Advantages

Low speed; easily understood by unskilled people; low cost

Low cost; simple; low speed

Simple; easy to operate and maintain

Efficient; wide range of capacity and head

Good for small-diameter bore-holes; ease of operation

Moving parts on surface; ease of operation

Disadvantages

Low efficiency; limited use; maintenance more difficult when cylinder is in the well

Low efficiency; limited use; maintenance more difficult when cylinder is in the well

Low efficiency limited use

Moving parts and packing require attention

Moving parts in well; rather expensive; requires good maintenance and operation

Limited application; low efficiency; moving parts require attention

4. The lowest water level expected during pumping.

5. The desired water pressure at ground level.

6. The type of power available (If electric, specify voltage, phase, frequency, etc.)

7. The total depth and nature of source.

PUMPS AND PIPES

Generally, pump size determines appropriate pipe sizes, and vice versa.

Pumps

The types most commonly used in small community water systems are:

1. Hand-or power-operated reciprocating pumps with the cylinder above the ground.

2. Power-operated centrifugal pumps with pump mechanism above ground.

3. Hand-power-, or wind-operated reciprocating deep-well pumps, with cylinder in the well.

4. Deep-well turbine pumps driven either from the surface or from a submersible electric motor.

5. Jet pumps, power-driven at surface.

6. Hydraulic rams

7. Air-lift pump, operated by power-driven compressor on the surface.

Classification of pumps (see Table 5 )

1. Displacement

a) Reciprocating

b) Rotary

c) Chain

2. Velocity

a) Centrifugal

b) Jet

3. Airlift

4. Hydraulic rams

Where various pumps are used:

1. Reciprocating plunger - in wells mainly. The most commonly used pump.

2. Semi-rotary pumps - for low lift e.g. from wells and cisterns to overhead tanks.

3. Rope-and-bucket systems - in open duo wells. Either hand or windless operated.

4. Chain-bucket pump - in open dug wells.

5. Chain-and-plug bucket.

6. Multicellular band pump.

7. Centrifugal pump - in deep wells.

8. Jet pump - in deep wells.

9. Airlift pumps - in drilled wells and wells with irregular sides, also for pumping muddy water.

10. Hydraulic Rams - in springs, streams and rivers.

Examples of various pumps.


Fig. 27 Hydraulic Ram

A = Supply-litres/minute

B = Difference in elevation between ram and supply-power head

C = Length of drive pipe

D = Difference in elevation between ram and highest point to which water is to be elevated-pumping head

E = Total length d supply pipe

F = Stand pipe, necessary in case of exceedingly long drive pipe

Under the proper circumstances-a situation similar to that shown, In which the supply of water is considerably In excess of the needs' and is situated so that the ram can be located well below the supply-the hydraulic ram can be an excellent solution to a pumping problem

When writing to manufactures about ram sizes, the information in items A, B, C, D, and E is necessary With this the factory will be able to recommend the correct size, feasibility, etc.


Fig. 28 Typical Installation of Jet Pump

A = Water being returned from pump above

B - Water from well being sucked up into throat (D) by high velocity discharge (C)

A =Jet assembly

B = Water line from pump to nozzle

C = Rising water

D = Centrifugal pump

E = Pressure-regulating valve

F = Discharge pipe

G = Height Or water pushed by jet

H = Suction by centrifugal pump (about 4 5 6 m, or 15-20 (t)


Fig. 29 Displacement Pump Operation

A = Down-stroke: Cylinder above plunger fills while valve at base of cylinder closes, and valve in plunger opens.

B = Upstroke: Cylinder full of water above plunger is expelled while, at the same time, valve at base of pump opens, filling cylinder below plunger. As plunger rises, a vacuum is formed below, pulling water into the cylinder.

When the cylinder is above ground, a foot valve is necessary to avoid priming.


Fig. 30 Elementary, Single Acting Force Pump

Adapted by kind permission from Graham. F. D. & Emery, T. J. (1942) Audel's Plumbers and steam filters guide, No 1, New York p. 2748.


Fig. 31A Centrifugal Pumps

In addition to the loot and bucket valves of the lilt pump. a head valve Is provided. In operation, during the up-stroke. atmospheric pressure forces water into the cylinder; during the down-stroke, this water is transferred from the lower to the upper side d the piston.


Fig. 31B Centrifugal Pumps

This is the best and simplest arrangement for centrifugal pumps. Power unit may be electric motor or internal combustion entire.

Belt-driven centrifugal pumps are common but introduce belt maintenance. Necessary in order to get the correct engine-pump speed ratio.

The manufactures recommendations for operation and maintenance should be followed

3. Choose a pipe size, so that velocity through it will be about 6 feet per second.

4. Estimate the pipe friction loss "head" (10 foot "head" represents the pressure at the bottom of a 10 foot high column of water) for both suction and discharge piping, using the following table.

TABLE 6: AVERAGE FRICTION LOSS FOR WATER FLOWING THROUGH PIPE WHEN VELOCITY IS 6 FT./SECOND.

Pipe inside diameter

1'.

2"

3"

4"

6"

8"

12"

24"

F = approximate friction head (ft.) per 100 ft. pipe

16

7

5

3

2

1 1/2

1

1/2

 

Friction Loss Head = F x length of pipe/100

Any bends, valves, constrictions, and enlargements (such as passing through a tank) add to friction. The equivalent pipe length of such "fittings" in the pipe line should be added to the pipe length used in the friction loss equation.

5. Obtain "Total Head" as follows:

Total Head = height of lift + friction loss head.

Using a straight edge connect the proper point on the "Total Head (ft.)" line with the proper point of the "Discharge U.S. gallon/ minute" line. Read motor horsepower and pump size (diameter of discharge outlet), choosing the printed values just above the straight edge.

Note that water horsepower is less than motor horsepower. This is because of friction losses in the pump and motor. The nomograph should be used for rough estimate only. For an exact determination give all information on the flow and piping to the pump manufacturer. He has the exact data on his pump for various applications. Pump specifications can be tricky especially if suction piping is long and the suction lift is great.

Example:

Desired - to pump 100 gallons/minute 50 feet high, no fittings

Pipe Size - 3" (for 6 feet/second) reference: Handbook entry "Velocity of Water in Pipes"

Friction loss head - about 3 feet.

Total head - 53 feet.

Pump size - 2"

Motor horsepower - 3 H. P.


Fig. 32 Pump size and horsepower requirement

ADAPTED FROM NOMOGRAFIC CHARTS BY C.A. KULMAN COPYRIGHT 1951. M GRAW HELL BOOK co. Inc. BY PERMISSION

If you plan to use human power for the pump, figure that a man can generate about 0.1 H.P. for a reasonably long period and 0.4 H.P. for short bursts. From this and the total head, you can predict the flow you should design the hand pump for.

Pipes

Most commonly used pipes are made of:

a. Galvanized wrought-iron and cast iron

b. Asbestos

c. Transite (mixture of cement and asbestos fiber)

d. Lead e. Copper

f. Plastic

g. Bamboo stems and other related tropical plants

h. Wood-stave, made out of light wood

Measuring diameters: The diameter of a pipe is determined by measuring the inside diameter.

 

Financing the project

The stock reply to questions about financing is that the country, state, province, or community concerned is too poor to afford the cost of needed improvements. Upon investigation, however, it often turns out that public money is being spent for projects which are of much less importance and which cannot possibly give the same returns as those obtained when the same amount of funds is invested in the construction of public water-supplies. There is usually a way to obtain long-range financing for rural water-supply programs if the individuals concerned with the problem will look far enough for a good case to present to their legislators or to financial institutions. Long-range plans have been effective in many countries throughout the world, both in the Western and Eastern Hemispheres. Most of them are the result of the work of a few people who have succeeded after painstaking efforts, in convincing the right government or bank of the importance of sanitation work.

In almost all successful programs, federal or central governments have shouldered the responsibility for financing the construction of small rural water projects. In many cases this decision will have been made by the time you begin. Because of the lack of credit on the part of most rural towns and villages and the absence of a system of financing public works through direct loans from private banking institutions, the central government must usually fill the role of provider of funds. In some places the states or provinces co-operate. In many countries, the normal pattern is for the central government to loan the necessary funds directly to a local community at a low rate of interest or to make a partial grant, with the community and state jointly, supplying the remainder. Loans or grants are made on the basis of projects presented through proper channels for approval by state or federal engineers. A sanitary engineering section in a central health department would be qualified and might be available to provide this technical service to rural communities.

In many financing plans the community is expected to contribute labor, land, local materials, end some services to the project, because these may be easily obtained locally and are often very reasonable in cost to the community. As a matter of fact, where the town or village is receiving a grant, it should at least be required to contribute those things that are available locally. Such a system offers an excellent opportunity to foster in the community a sense of ownership and pride in something which its members had to toil hard to achieve.

Co-Operative projects are not always appreciated by government administrations, which often fall to understand their great advantages and significance from the standpoint of public relations and interest. It is true that such projects are slow of execution and that great patience and tact are demanded if they are to be carried through to successful conclusion. However, they are indispensable when large numbers of community water-supplies are to be constructed in areas of poor economic possibilities. In some areas original cost estimates of new water-systems have been reduced by as much as 50% because the local people were able to furnish all the unskilled labor as well as services such as transportation, office space, warehouses, etc., plus all the local materials required.

Thus, you, by taking the initiative, can successfully, over a long period, accomplish a great deal in the realm of rural water-supply development.

When estimating the cost for the project, you should carefully calculate costs for the following items:

1. Materials - List all materials needed

2. Labor

3. Transportation

As a general rule of thumb, labor should be about 25% of the cost of the project, materials about 70%, and transportation the remaining 5%. Although this will vary for particular situations, large variations from these guidelines should be carefully examined.

In countries where water systems have been built, it has been found that the total cost of the water system can be recovered in 3 to 5 years by the reduction in cost of sickness and death from water-born diseases and the actual money outlay to buy water from vendors. In money, only, the capital savings for a ten year period can be as high as 800%. In addition to financial savings, a pure water system can reduce 75% of the sickness and death caused by water-borne diseases as well as increasing the amount of pure water available seven-fold. This information will be appreciated by local people and government administrators and should be used to promote necessary financing for rural water-supply programs.

 

Lesson plans

PLANNING THE DISTRIBUTION SYSTEMS

LESSON NO. 1

LESSON OBJECTIVE: To determine existing facilities which may be useful as part of the planned system.

TOPIC

INSTRUCTIONAL

PROCEDURE

SUPPLEMENTAL MATERIALS RELATED READING

Water Sources

Lecture on various types of possible water sources and their characteristics.

Pictures of various sources. Chart on characteristics of source

 

Show how to use tables in determining the yield of a source.

Water sources, floats, current meters, weirs. tables on yield.

 

Demonstrate how to measure velocity of water.

Individual Water Supply Systems, p. 24-52.

Pumps

Ask students the conditions under which a pump is necessary to distribute water.

Models of pumps. Photographs and/or drawings of pumps.

 

Briefly mention pumps used in large systems(stress it is not the concern now).

Chart giving characteristics of pumps.

WHO Monograph Series #42.

Chapter 4.

 

Lecture on the characteristic features of pumps most often used in Rural Water Supply.

 

Pipes

Ask students to name materials most commonly used for pipes.

Samples of pipes from various materials, measuring scales & gauges

 

Add local materials omitted by the students.

 
 

Demonstrate how to measure pipe diameters.

 

Geographic Locations

Show general areas where the Peace Corps will go.

World Map

Atlas of climatic regions of the world, showing: relief, vegetation, seasonal rainfall and temperature distributions.

 

Lecture on climate of each region.

 
 

Discuss in class possible hindrances to construction work.

 
 

Group them on the board under causative.

 

Local Materials

Lecture on trade-off values: e.g., quality vs. expenses to achieve convenience.

 
 

Discuss in class the materials which can be adapted to suit an improved distribution system.

 

 

PLANNING THE DISTRIBUTION SYSTEMS

LESSON NO. 2

LESSON OBJECTIVE: To choose the most suitable source for development and select a suitable site for the system facilities.

TOPIC

INSTRUCTIONAL PROCEDURE

SUPPLEMENTAL MATERIALS RELATED READING

Selecting Water

Source

Discuss the possible combination of characters a source can have.

Section on Sources.

 

Let each student draw the characteristics of the source he would choose first.

 
 

Discuss the feasibility of each proposal.

 
 

Formulate a guide to quick choices.

Monograph Series #42

pp. 34-35.

Selecting the site

Discuss the importance of proper locations of facility sites.

Suggested Design Criteria: or Waterworks in Recreational Areas, Sections 2-4 and 9 3.

 

Draw a guide to site selection.

 

 

PLANNING THE DISTRlBUTION SYSTEMS

LESSON NO. 3

LESSON OBJECTIVE: To select pumping equipment most suited for use in rural areas.

TOPIC

INSTRUCTIONAL PROCEDURE

SUPPLEMENTAL MATERIALS/ RELATED READING

Characteristics of Pumps.

Ask students to recall characteristics of pumps.

Section on character

 

Discuss with students what would be the best guide criteria for choosing a pump.

Pumps and/or pump models.

 

PLANNING THE DISTRIBUTION SYSTEMS

LESSON NO. 4

LESSON OBJECTIVE: To describe the community to be served; specifically, the aspects that affect the plan.

TOPIC

INSTRUCTIONAL PROCEDURE

SUPPLEMENTAL MATERIALS/ RELATED READING

Relation

Lecture on how to estimate the population of a community.

 
 

Show how to calculate projected population and relationship between population and demand .

WHO Monograph Series #42,

p. 42-43.

Solutions and al Structure

Discuss the importance of long established traditions.

 
 

Discuss what traditions are likely to clash with the planned system and how to avoid such a clash.

 

Atomic Standard

Discuss the connection between occupation and water demands.

 
 

Relate type of houses to distribution systems

 
 

Compare availability of skilled labor in U.S. to underdeveloped countries.

 
 

Discuss how to select workers for the project

 

 

PLANNING THE DISTRIBUTION SYSTEMS

LESSON NO. 5

LESSON OBJECTIVE: To prepare a chart projecting expected costs of material and labor. Estimate the required amount of money and how to raise the money.

TOPIC

INSTRUCTIONAL PROCEDURE

SUPPLEMENTAL MATERIALS RELATED READING

Cost

Discuss how to estimate the coat of the project.

WHO Monograph Series #4

pp. 28-33.

 

Discuss various methods.

Financing Statements

Section 6