Desah~tion, 64 (1987) 193-202 193 Else&r Science Publishers B.V., Amsterdam - Printed in The Netherlands

WATER RESOURCES DEVELOPMENT IN RIYADH, SAUDI ARABIA

IBRAHIM S. AL-MUTAZ

Chemical Engineering Department, King Saud University, P. 0. Box BOO Riyadh 11421, Saudi Arabia

ABSTRACT

The water demand in the Saudi Arabian capital, Riyadh, is growing in accor-

ding with the vast population growth. The principal source of water in Riyadh

is Minjur aquifier, a sandstone aquiter more than 1200 meter below ground. It

has high hardness, sulphate and salinity. There are numbers of reverse osmosis

plants to supply fresh water to the city with a total capacity of about 192,000

cubic meter per day. By 1981, fresh water was delivered from Al&bail desali-

nation plant through twin pipelines each is one meter and half in diameter and

about 930,000 meter long. These pipelines are capable of delivering approxima-

tely 830,000 cubic meter of fresh water per day from Al-Jubail to Riyadh. The

prementioned population growth at an approximate rate of 50,000 per year and

the enlargement of social and industrial activities require an increase in the

water supply. This paper analyzes the water demand and supply in Riyadh. It

also outlines the possible water resources including the processed water to

satisfy the increasing rate of water consumption.

INTRODUCTION

Saudi Arabia is a dry country. It has scarce surface water resources. Hydro-

logical investigations pointed to the large resources of underground water of

two types, replenishable and non-replenishable. Replenishable ground water with

an average age of 10 years has a volume of more than 200 million m3. It is

mainly found in the central part of Saudi Arabia where the capital, Riyadh, is

located. A proven reserve of 338 billion m3 of non-renewable subsurface water

is estimated which may be formed some 20,000 years ago.

Instead of exploiting these ground waters, the government planned to rep-

lenish it by constructing large number of dams with a total storage capacity of

248s463*ooo "5(l). Digging wells are illegal in the country without the per-

mission of the Ministry of Agriculture to minimize the unnecessary utilization

of the ground water reserve.

OOll-9164/87/$03.50 0 1987 Elsevier Science Publishers B.V.

194

Water consumption in Saudi Arabia in general and in the capital city,Riyadh,

in particular increases rapidly in the last few years. Population in Riyadh was

about 170,000 in 1964, 665,000 in 1974. Nowadays, it approaches one million. In

the following sections, the major sources of water in Riyadh together with the

consumptions and uses are reviewed in order to present an example of the Saudi

water resources program.

WATER RESOURCES IN RIYAOH

The main sources of water in Riyadh are the shallow wells in Wadi Nisah,

Wadi Namar and Wadi Hayir and the deep wells of Minjur formation. In 1964, the

principal Riyadh water sources are(l)

- 9 deep wells tapping the Mijur formation.

- 18 shallow wells; Wadi Nisah 5 wells, Wadi Namar 7 wells, Wadi Hayir 6 wells.

These wells produced about 80,000 m3/day which was sufficient for the whole

city. A dramatic increase in the water demand was observed due to the rapid

development and growth of Riyadh in the past decade. The population growth was

at an approximate rate of 50,000 per year. So many of the shallow wells were

exhausted. At present, the following are considered the main sources of water

in Riyadh(2):

- Wadi Hanifa and its tributaries.

- Byad-Wasia aquifer, (Wadi Nisah well field)

- The deep-lying Minjur aquifer (about 2000 m below ground).

- Delivery of fresh water from Al-Jubail II desalination plant.

About 830,000 m3/dsy of fresh is delivered from Al-Jubail, at the eastern

part of Saudi Arabia to Riyadh. This massive amount of water is transported by

twin 60 inch in diameter pipelines of 930 Km total length. It is part of 3

million meters of pipelines capable of delivering 2 million d/day from

Al-Jubail to cities and villages in the Red Sea and Arabian Gulf, as well as in

the interior of the country. The design capacity of Al-Jubail II plant is

960,000 m3/day (253.5 mgdl.

Anyhow, Minjur aquifer is the source of Riyadh desalination plants. Table 1

shows the major treatment plants in Rfyadh. All these plants use reverse osmo-

195

sis system wiht DuPont hollow fiber and polyamid membrane except Buwab plant

which has a spiral wound configuration and cellulose acetate membrane.

Table 1 : Major Water Treatment Plants in Riyadh

Water

Startup Permeate Slipstream Blend RO Reject recovery

Plant date m3/hr m3/hr m3/hr m3/hr %

Manfouha 1 1980 1363 438 iaoi 140 90.7

Manfouha 2 I980 1817 583 2400 I80 91.0

Malez I980 908 292 1200 95 90.5

Shemessy I980 1363 438 IaoI I40 90.7

Salbukh 1979 1921 613 2534 215 89.9

Buwayb I980 I875 583 2458 250 88.2

Total 192,000 61,000 254,000 24,400 90.2

Source: Ref. (2).

Riyadh also has a wastewater treatment plant to provide water for irrigation.

The plant was constructed in 1972 with a capacity of 40,000 m3/day. It included

a two-stage trickling filteration. By 1980, the plant capacity increased to

80,000 m3/day and then to 200,000 m3/day in 1982. About 20.000 m3 of this

reclaimed water is delivered to Riyadh Refinery, the balance is available for

irregation of 1.600 hectares at Dirab and 1,500 hectares at Dirayah(31.

WATER QDALITY

The quality of water in Wasia-Biyadh aquifer is relatively good. The average

total dissolved solids are 2,500 ppm in the

AlDahna. It reaches 15,000 ppm at the north

The Minjur formation is consisted of the

- The upper Minjur aquifer system.

- The middle Minjur shales and mudstones.

- The lower Minjur aquifer system.

region of west Khurais and west

of Jaham and Ma'agala.

following geological systems:

The upper Minjur system is the main formation that provides most of Riyadh's

present water supply(l). Its quality varies from about 1200 ppm to 2800 ppm.

Table 2 shows the composition of drinking water from three water treatment

196

plants in Riyadh as compared to the recommended World Health Organization, WHO,

standards. In Table 3, compositions of raw and product water at Buwayb and

Salbukh plants are given. The suitability of the treated wastewater for irriga-

tion is demonstrated in Table 4.

Table 2: Riyadh Water Quantity in ppm

Constituents WHO Standards Malez Manfouha Shemessy

Chloride, Cl- 200-600 270 180 170

Sulphate, S04-- 200-400 450 370 300

Calcium, Ca++ 75-200 40 40 40

Magnessium, Mg++ 30-150 46 36 36

Total Dissolved

Solid, TOS 500-1500 1100 900 800

Total hardness,

megv/liter 2-10 5 5 5

Source: Ref. (2).

Table 3: Quality of Water at Buwayb and Salbukh Plants

Ionic Buwayb Salbukh

Composition Raw RO Feed Permeate Blend Raw RO Feed Permeate Blend

Ca 208 140 4 72 173 26 2 44

Mg 75 59 2 26 73 34 5 23

Na 150 220 24 78 164 352 24 98

K 45 45 7 21 40 35 6 20

Fe 0.8 0 0 0 1.2 0 0 0

HC03 140 60 20 40 138 7 3 56

Cl 405 400 56 160 297 314 24 97

SO4 552 572 10 192 490 523 34 120

Si02 57 16 3 11 24 11 2 7

TDS 1620 1516 128 604 1410 1300 100 470

PH 8 5-5.5 5.5-6 7.5-8 8 5-5.5 5.5-6 7.5-8

Temp.,OC before cooling 60-70

after cooling 30-35

Source: Desalination 45, 17, 1983.

55-60

30-35

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Table 4: Chemical Composition of Riyadh Treated Wastewater, ppm

Constituents Ground Water Treated Effluent

Hardness

PH

Electric cond., mnhos/cm

SAR*

TDS

Chlorides

BOD

Bacteria

Nitrogen

Potash, K20

Phosphate as P

757

7.6

2.0

3.12

1500

337

350

6.9-8.2

2.4

3.0

1400-1600

300-375

10-50

100-100 ml

40-60

lo-60

IO-20

* Sodium adsorption ratio = Na+

k!Ca*+ + Mg++)

Source: Ref. (3).

WATER DEMAND AND USES

According to Altinbilek and Akyurt(4). the important factors that influence

the daily average water demand are:

climate

socioeconomic characteristic of the city

size of the city

types of industrial and connaercial activities

extent of sewerage

quality of the water

abundance of public and private water supplies

completeness of meterage

cost of the water

pressure in the distribution system

management

The projected water demand in Saudi Arabia is 5724 million m3/day in 1990

and 6523 million m3/day in 2000(5). Agriculture accounts for more than 80% of

the water consumption. It rose from less than 2000 million d/day in 1980 to

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7430 million in 1985. Table 5 presented the national water resources and demand

balance.

Table 5: National Water Resources - Demand Balance

Million m3/hr

14OOAH(1980) 1405AH

Demand:

Agriculture 1860 7430

Domestic, Industrial, Others 502 1400

Total 2362 8830

Resource:

Sulphate Water 485 900

Ground Water:

Renewable 660 950

Non-renewable 1154 6480

Desalinated Seawater 63 400

Reclaimed Wastewater 100

Total 2362 8830

Source: Fourth Five-years Development Plan 1985-1990,

Ministry of Planning, Kingdom of Saudi Arabia, 1985.

% Share

1405 AH

84

16

loo

10

11

73

5

1

loo

The Economic Coasafssion for Western Asia, ECWA, studied the water demand in

the region(6). They found the following models for water demand in Saudi Arabia:

a) The municipal water demand.Y2* gal per capita per day

Y1 = 22.85 + 4.66 POP + 0.0002 ENRO

b) The industrial water demand, y2, gal per capita per day

Y2 = 122.53 + 25.33 POP + 0.0016 TGP

c) The agriculture water demand, Y3, gal per capita per day

Y3 = 5.36 + 7.32 POP + 0.0071 PPC

where POP is the total population in millions

ENRO is the total student

in thousands

TGP is the total natural

PPC is the production of

199

enrolment by all levels of education available,

gas production in millions of cubic meters

principal crops in thousands of metric tons

In Table 6 values of these variables are shown together with the estimated

water demand in the corresponding fields.

Table 6: Values of the Saudi Water Demand Model

Year POP ENRO TOP PPC YI Y2 Y3 Total demand

1970 7.74 484 2300 829 59 77 68 204

1975 8.93 746 3300 914 67 109 77 253

1980 9.93 1000 4980 1050 70 137 86 293

1990 12.12 1500 6000 1220 80 194 103 377

2000 14.50 2000 6000 1400 91 254 121 466

This model predicted somewhat higher water demand rate than the government

predictions. As indicated before the projected total water demand is 6523 mil-

lion m3/year in 2000 compared to 9335 million m3/year estimated from ECWA model.

Ukayli and Husain(7) developed a simple water demand mdel base on the water

utilization data of Table 7. This demand model is given by the following

equation

Dt = a exp(bt1

where, Dt is the demand in million cubic meter/year at time t.

t is the time in years, t=D at year 1399AJi (1979).

a & b are regression coefficients; the coefficient a indicates the

initial demand and b the growth rate. For total water demand,

a = 4715.9 and b = 0.0162.

This equation yields a demand of 6627 million m3/year at 2000 which is less

than 1.6% higher than the predicted government figure. Anyhow this accuracy is

expected since the proposed model is just a fit of the water data of Table 7.

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Table 7: Projected Water Balance in Saudi Arabia

Water Resources

Non-renewable

Renewable

Desalination

Urban Waste

Water Utilization

Urban and Industry

Rural and Livestock

Irrigated agriculture

Surplus

Total Resources

Total Utilization

(million g/year)

1980 1985 1990

3450 3450 3450

1145 1145 1145

63 605 794

__ 140 335

502 828 1211

27 28 31

1832 1873 2345

2247 2611 2137

4658 5340 5724

4658 5340 5724

3450

1145

1199

730

2279

38

3220

986

6523

6523

Source: Ref. (5).

Ukayli and Husain(7) also found a water demand model for Riyadh of the simi-

lar form. This model based on the following equation.

dt = 151.93 exp(0.0645t)

where, dt is the demand in thousand cubic meter per day.

Table 8 shows the water consumption and demand in Riyadh according to the

Ministry of Agriculture and Water reports. However, the distribution of these

consumption among the various possible activities has been studied by Baymer

and James(8). They found that with good water management, the total water con-

sumption per capita will be 208 liter/dqy. By probable design, the daily con-

sumption will rise to 385 liter/person. While poor management will lead to a

consumption rate of 970 liter/day per capita. Their results have been given in

Table 9.

201

Table 8: Estimated Water Demand and Consumption in Riyadh

Year Population Consumption Total Demand Total demand

(LPcd) consumption (Lpcdl m3/day

1970 355,000 240 86,000 180 71,000

1975 525,000 280 147,000 200 118,000

1980 685,000 300 205,000 220 173,000

1985 900, COO 300 270,000 240 252,000

1990 1,050,000 300 315,000 260 325.000

2000 1,400,000 300 420,000 300 519,000

Source: Ref. (1).

Table 9: Forecast Water Use in Riyadh Liter per Capital per Day, Lpcd

Standard Household Conaaercial Industrial Recreation Leakage Total

Very good 130 27 20 10 21 208

Probable 200 40 30 25 90 385

Poor 530 120 60 60 7200 7970

Source: Ref. (8).

CONCLUSIONS

Inspite of the fact that the water consumption data in Saudi Arabia is incon-

sistant and incomplete(91, the government managed to supply excessive water in

all cities. Water resources in the country are adequate. In Riyadh, ground

waters are enormous and have relatively good qualities. Rechargement of this

subground waters took more attention than exploring it. So about 830.000 m3/day

of fresh water is transported from Al-Jubail desalination plant to Riyadh.

Utilization of reclaimed waste water for irrigated landscaping and industr-

ial uses will result in saving a considerable resource of water. Nearly 100

million m3/year had been made available for use by 1985 near the large cities.

Many sewage and purification stations are planned in the future.

It has been declared that the objectives of the water development in Saudi

202

Arabia are(l0):

- to meet the present and future water needs of society.

- to limit the development of all water resources to product levels and to

effect their conservation in accordance with the long-term needs of the

Kingdom.

- to enhance the utilization of existing water resources through the con-

struction of dams for recharging aquifers, and through improved methods

of collection, treatment and utilization of sewage water.

Riyadh is considered a good place to observe the achievement of these objec-

tives, since it has all type of the Kingdom's water resources. It also grows

rapidly as compared to other Saudi cities. So its water resources development

gives a full picture of the country water development programs.

REFERENCES

l-

2-

3-

4-

5-

6-

7-

8-

9-

lo-

Khatib, A.B., "Seven Green Spikes", 2nd ed., Ministry of Agriculture and

Water, Suadi Arabia, March 1980.

Ghulaigeh, A., and Ericsson, B., "Riyadh's RO Water Treatment Plants - The

Largest Demineralization Complex in the World", Proceeding of the 1st Con-

gress on Desalination and Water Use, Bahrain, 1979.

Rowe, D.R.. Al-Dhowailah, K., and Whitehead, A., "Water Reuse in Riyadh",

Symposium on Water Resource in Saudi Arabia, the College of Engineering,

King Saud University, Riyadh, April 1983.

Altinbilek, H.D., and Akyurt, M., "Desalination for Municipal Supply",

Proceeding of the Second SOLERAS Workshop, Denver, Colorado, March, 1981.

"Third Five Year Development Plan, 1980-1985", Ministry of Planning,

Kingdom of Saudi Arabia, 1980.

"The Projection of Water Demands for ECWA Countries by the Year 2000".

Economic Conanission for Western Asia, UN, Second Regional Water Meeting,

Riyadh, January 1979

Ukayli, M.A., and Husain, T., "Decision Making in Water Resources Planning

for Saudi Arabia", Symposium on Water Resources in Saudi Arabia, The

College of Engineering, King Saud University, Riyadh, April 1983.

Balmer, R., and James, W., "Water Demand and Reuse", Report Prepared by

British Arabian Advisory Company and the Water Resources Development

Department at the Ministry of Agriculture and Water, Kingdom of Saudi

Arabia, October 1980.

Dracup, J.A., "Desalted Fresh Water Demand and Supply Projection, A Case

Study of Saudi Arabia", Proceedings of the 7th International Symposium on

Fresh Water from the Sea, Vol. 1, pp. 19-29, 10980.

"Third Five-Year Development Plan 1985-1990". Ministry of Planning,

Kingdom of Saudi Arabia, 1985.