ST/ESA/120

Department of Technical Co-operation for Development

Natural Resources/Water Series No. 10

EXPERIENCES IN THE [DEVELOPMENT AND MANAGEMENT OF INTERNATIONAL RIVER AND LAKE BASINS

Proceedings of the United Nations Interregional Meeting of International River Organizations

Dakar, Senegal

5-14 May 1981

United Nations New York, 1983 PLANNING THE DEVELOPMENT AND UTILIZATION OF INTERNATIONAL RIVERS: THE

Ministry of Irrigation,

Planning the development and utilization of water resources of international rivers is an undertaking of major importance. Egypt is one of the pioneer countries, with wide experience in this field, since life in Egypt has, for centuries been based totally on agriculture irrigated by the waters of the River Nile. The hydrological regime of the Nile has been studied for more than 1,000 years.

Egypt, which lies in the downstream area of the Nile basin, signed the first Nile Water Agreement with the in 1929 with a view to developing jointly the beneficial potential of the river. Prior to the Aswan High Darn project, in 1959, another agreement was concluded by Egypt and the Sudan concerning the full utilization of the Nile waters. Negotiations are now under way between the nine Nile countries in order to establish a joint commission for achieving the rational utilization and development of the Nile for the benefit of all the States. In Egypt, projects and studies have been started to develop this water resource and improve methods of irrigation.

A. The River Nile as an internaticnal river

The River Nile is considered the second of the world in length, 6,699 kilometres; its southern source starts at latitude 4* south, and empties into the Mediterranean Sea at latitude 31* north. The river basin extends over the north-eastern corner of and has an area of about 2.9 million square kilometres, covering parts of the land of nine countries, namely, Burundi, Egypt, , Kenya, Rwanda, Sudan, Uganda, United Republic of Tanzania and Zaire. Throughout this wide area, climate, vegetation, animal life, peoples, cultures, features and religions are diverse.

The Nile receives waters from two main sources: (a) the equatorial lakes plateau; and (b) the Ethiopian plateau.

In the equatorial lakes plateau, water is collected from the basins of Lakes Victoria, Kioga, Albert, Edward and George, constituting the Albert Nile - having an average annual discharge of 26.5 billion m . Starting from Niraule at the southern boundary of Sudan, the Albert Nile changes its name to Bahr El Gebel. Trie Bahr El Gebel gains about 4.8 billion m^ annually in its southern part from many torrents, and its annual average discharge reaches about 30 billion nH at Mongalla. The Bahr El Gebel then passes from north of Mongalla throughout a swampy and region, where it loses about 50 per cent of its discharge: only 15 billion m-^ annually arrives at its confluence with the .

Moreover, the White Nile gets some of its water from the basin of Bahr El Gazal whose catchment area is 526,000 km^. Nevertheless, most of the water 2 collected from this basin is lost in the swampy area of 40,000 km near its end to the west of . Trie average annual total discharge from the main tributaries of Bahr El Gazal, before the swampy area is reached is 15 billion irr; but only 0.5 billion mJ reaches from it to the White Nile.

-293- From the Ethiopian plateau, the river gets its water from its main tributaries; the , the. and the Atbara River. The average annual inflow from the Sobat River is 13.5 billion m , of which 2.8 billion from its southern branch, the River, and 9.2 billion from its other main branch, the at its outlet in the Sobat, while its discharge is 13.0 billion m at Gambeila in Ethiopia. This shows the high losses in this reach of the Baro River due to evaporation from the swampy areas and overspilling from channel sides, especially from its northern side, which results in a spread of a huge quantity of water lost in the area of the Machar Marshes. Another discharge of about 2.8 billion m3 flowing from the eastern khors, fed from the Ethiopian plateau, is annually lost in the Machar Marshes.

The Blue Nile has its source at Lake Tana in the Ethiopian plateau, having an average discharge at its outlet of 2.8 billion m3 annually. Many tributaries then flow into trie Blue Nile, increasing its discharge at Roseires to 50 billion m3 annually and at Khartoum to 54 billion m3 annually. The Blue Nile constitutes the main source of the Nile flood waters, along with the Atbara River, and has played the major role in producing the delta from flood silt deposited throughout many centuries.

The Atbara River, also fed from the Ethiopian mountains near Lake Tana, adds to the annual flow of the Nile about 12 billion m3.

In sum, the average annual natural discharge of the Nile, deriving from its different sources, is about 84 billion m3.

E. The Agreenent between Egypt and the Sudan for the Corrplete Utilization of the Nile Waters 1/

The main elements of the agreement concluded between Egypt and the Sudan in 1959 can be summarized as follows:

(a) The Nile waters used by Egypt prior to the signing of the agreement, calculated at 48 billion m3 annually at Aswan, were regarded as her acquired right. The acquired right of the Sudan was 4 billion m3 annually, as measured at Aswan;

(b) in order to regulate the river waters and control their flow into the sea, the two States agreed that Egypt should construct the Aswan High Dam as the first link in a series of projects on the Nile for long-term storage;

(c) In order to enable the Sudan to utilize her share of water, the two States agreed that the Sudan should construct the Roseires Dam on the Blue Nile;

(d) The net benefit from the Aswan High Dan Reservoir was calculated on the basis of the average natural river yield of water at Aswan, estimated at 84 billion m3 annually. From this the total acquired rights of the two States (52 billion m3), and the average losses due to long-term storage of the Aswan High Dam are subtracted. The net benefit (22 billion m3) is divided between the two States at the ratio of 14.5 billion m3 for the Sudan and 7.5 billion m3 for Egypt. These shares are added to their acquired rights. Any yield in excess of the average natural river yield is equally divided between the two States;

-294- (e) Egypt agreed to pay to the Sudan 15 million Egyptian pounds as full compensation for damage resulting to Sudanese existing properties as a result of the storage in the Aswan High Dam Reservoir;

(f) The Sudan agreed to construct projects for increase of the river yield by preventing water losses in the swamps of Bahr El Gebel, , Bahr El Gazal and its tributaries, the Sobat River and its tributaries, and the White Nile basin. The net yield of these projects and their total costs v/ould be equally divided between the two States;

(g_) In order to ensure technical co-operation between the two States, to continue the research and study necessary for control projects on the River Nile and increase of its yield, and to continue the hydrological survey of its upper reaches, the two States agreed to form a Permanent Joint Technical Commission composed of an equal number of members from both parties. Its functions include the drawing up of basic outlines of projects for increase of Nile yield, supervising the execution of the projects approved by the two States, and devising a fair arrangement for the two States to follow in conditions of low river flows; (h) The two States agreed to discuss any claim by other riparian countries. If any amount of the Nile waters should be allocated to any of these riparian countries, this amount would be equally deducted from their water shares.

C. The proposed Nile Basin Commission

In order to attain the best possible co-operation between the nine riparian Nile countries for the adequate development, control and management of this important resource, and based on the recommendations adopted by the United Nations Water Conference convened at Mar del Plata, Argentina, in March 1977, talks and negotiations are now under way between the Nile countries for the purpose of establishing a Nile Basin Commission, composed of one representative from each of the member countries (Burundi, Egypt, Ethiopia, Kenya, Rwanda, Sudan, Uganda, United Republic of Tanzania and Zaire).

It is proposed that the objectives of the Commission be:

(a) To assist the member States of the Nile basin in co-operating in the rational planning of conservation, allocation and development of the water resources of the whole Nile basin;

(b) To conduct hydrological and hydrometeorological studies of the River Nile, its tributaries, and their respective catchment areas, and operate the existing hydrological and hydrometeorological networks;

(c) To establish data banks and make arrangements for systematic collection, processing, analysis, and periodic publication in an agreed format at specified intervals of time of hydrological and hydrometeorological data; also to assess periodically surface-water resources and forecast floods and drought;

(d) To sponsor studies pertinent to the conservation of the Nile waters with a view to minimizing losses and increasing the yield of the basin;

-295- (e) To sponsor studies on Nile control with a view to ensuring the best use of the~Nile waters in the interest of all riparian countries;

(f) To devise working arrangements for the dams, barrages, and control works constructed in the basin with a view to ensuring co-ordination of the efficient control of the Nile and its tributaries; (g_) To advise the riparian countries on the appropriate arrangements and water resources plans of the Nile basin, and on the formulation of master plans, utilizing the techniques of system analysis and mathematical modelling; to examine and recommend projects prepared by member States and follow up on the execution of studies and works;

(h) To standardize and promote equipment and methods of measurement, observation, collection and analysis of hydrological and hydrometeorological data;

(i_) To promote the exchange of technical information and experience in the field of water resources development and management among the riparian countries and other organizations;

(j_) To recommend drought and flood control measures in the Nile basin;

(k) To assist in the development of appropriate technologies in the field of water resources;

(1) To promote research in trie field of water resources development by strengthening existing research institutions and setting up new ones and exchanging results;

(m) To study the environmental impact of water resources projects within and outside the Nile basin and recommend appropriate measures;

(n) To review existing water resources legislation with a view to standardizing it;

(o) To promote training at the national and basin-wide level by improving the existing training institutions and promoting the establishment of a water resources institute within the basin.

Existing joint projects in the Nile basin

Sennar Reservoir

The Sennar Reservoir was constructed in 19 25 on the Blue Nile to serve two purposes: providing annual storage of 780 million m3 for irrigation in the Sudan Gezira and raising the river level to supply the Gezira Canal. The agreement, concluded in 1929 by the Egyptian and British Governments (on behalf of the Nile basin countries), contains rules for the regulation of the reservoir.

-296- Gebal El Aulia Reservoir In 19 32, Egypt and the Sudan agreed that Egypt should construct the Gebel El Aulia Dam; it was completed in 1937 on the White Nile, 44 km south of Khartoum in the Sudan. Its purpose was to provide annual storage capacity of 3 5 billion m3 (corresponding to 2.5 billion m3 at Aswan) for developing 600,000 feddans from basin irrigation to perennial irrigation in Egypt.

Owen Falls Dam In 1949, an agreement was concluded between Egypt and Uganda to construct the Owen Falls Dam on the outlet of Lake Victoria. The dam - completed in 1954 - provides long-term storage capacity for the benefit of Egypt, and hydroelectric power (150,000 kilowatts) for the benefit of Uganda. According to the agreement, the rules for the regulation of the reservoir^ state that the outflow from the reservoir should not be less than 44 million m per day for the purpose of power generation. Lake Victoria is used as a reservoir for long-term storage, having a capacity of 200 billion m3 for a height of 3 metres (between river levels 9.80 and 12.80 metres at Entebbe gauge). Egypt on the other hand, has not reached an agreement with the riparian countries about the necessary levels for storage in Lake Albert, or about the schedule for execution of the Jonglei Canal Scheme on the Bahr El Gebel.

The Aswan High Dam This is considered the first of the major projects, and the main link in the series of projects, for control of the Nile and development of its water resources. It was started in 1960 and completed in 1967. The main function of the Aswan High Dam was to produce an artificial lake of huge capacity for long-term storage, in order to store excess waters from years of high flow and discharge it in years of low flow. An additional capacity is allocated for depositing silt and another for protection against high floods. The total capacity of the Aswan High Dam Reservoir is about 164 billion m , including 30 billion as dead storage for silt trap, 90 billion for long-term storage and 44 billion for flood protection. This project gives a water benefit of 22 billion m3 annually - 7.5 billion for Egypt and 14.5 for the Sudan. The total cost of the project and its supplements was 460 million Egyptian pounds, paid by Egypt. The main benefits of this project accruing to Egypt are: (a) Conversion of 973,000 feddans in Egypt from basin irrigation, yielding one crop per year, into perennial irrigation for three crops per year; (b) Reclamation of new land - amounting so far to 919,000 feddans; (c) Ensuring the irrigation water necessary to cultivate at least 700,000 feddans annually, whatever the natural river discharge is; (d) Achieving elasticity in the agricultural planning in order to permit the expansion in any productive crop;

-297- (e) Protection against high floods and compensating the deficit in years of low flow;

(f) Generation of hydroelectric power of about 10 billion kilowatt-hours per year;

(g_) Increasing the national income by about 255 million pounds annually.

As in any major project, some side effects have appeared as a result of the Aswan High Dam, which are now under study. The main side effects of this project are:

(a) Degradation in the river bed and sides downstream from the Aswan High Dam due to the fact that the silt content of the water is deposited in the reservoir. Studies and research have proved that the rate of degradation is still within safe limits. The Ministry of Irrigation is now executing the first stage of the Toshka spillway channel in order to spill the excess water from the Asv/an High Dam Reservoir to a natural depression in the western desert, southward into the new valley for the purpose of minimizing the degradation problem;

(b) Change in the quality of water in the Aswan High Dam Reservoir and in that flowing past it. Studies have approved the suitability of the stored water for all civilian purposes;

(c) Protection of major dov/nstream works on the Nile channel against degradation;

(d) Effects on the ground-water table, and drainage of the cultivated lands downstream.

£- Joint projects for water resources development in the

The Jonglei Canal scheme

The losses in the swampy areas of Bahr El Gebel and Bahr El Zeraf are estimated to be as high as 50 per cent of the total-flow into this region. In order to control most of these losses, in 19 78 Egypt and the Sudan started the execution of phase I of the Jonglei Canal scheme, which is expected to be completed in 1984.

The Jonglei Canal project contemplates excavating a 345-km canal from Bur on the Bahr El Gebel to the White Nile near the confluence with the Sobat River. The main purpose of this project is to save the water lost by evaporation and seepage in the sudd region. The project will provide some secondary benefits, namely, a shorter navigation route between and Juba; a road on the eastern bank of the canal; a new source of fisheries; reducing the flooding of Zeraf Island; improvement of the ecology of the district and increasing the productivity of the land by ensuring a continuous flow of water throughout the year.

The maximum discharge of the canal in its first stage is 20 million m3/day, to be raised after the second stage to 43 million m3/day. The annual water benefit of the project is estimated to be 4.675 billion m3, as at Malakal after the first stage, and 8.118 billion m3 after the second stage. According to the

-298- 1959 Nile Waters Agreement, Egypt and the Sudan will share in the costs of the project and in the water benefits.

Project for control of losses in the Bahr El Gazal

The average annual total discharge from the main tributaries of Bahr El Gazal, before passing into the swampy area, is about 15 billion m3, while only 0.5 billion m3 reach Bahr El Gebel. The rest is lost in the swampy area of 40,000 km2 to the west of Lake No.

Studies are now being carried out by the Egyptian Ministry of Irrigation for proposing a joint project for the purpose of minimizing these large losses to the benefit of Egypt and the Sudan. The preliminary studies have proposed excavating two canals to collect water from the tributaries and swamps (see map 2);

The northern canal. Starting from Gogrial on the , with a capacity of 25 million m3/day, it increases - after receiving the water discharging from the - to 93 million m3/day; then it passes to the east to Khor Lol, where the channel is widened to carry its flow to the White Nile. The length of the proposed canal is 376 km. Many alternatives for the design of the canal are under study, giving a water benefit ranging between 9.8 and 5.0 billion m3 annually, with corresponding estimated costs of 366 and 158 million Egyptian pounds, respectively.

The southern canal. The canal will collect the waters from the southern tributaries and khors of the Bahr El Gazal basin in order to minimize its losses in the swampy area. The proposed canal starts from Tonj on the Tonj River with a capacity of 23 million m3/day, increasing - after receiving the waters from the rivers Jell, Naam and Yei - to 63 million m3 per day. The canal discharges its water in the Bahr El Gebel at Chambe. The canal length is 202 km. Many alternatives for the design of the canal are under study, giving an average water benefit ranging between 4.9 and 1.1 million in3 annually, with corresponding costs of between 57.0 and 13.6 million Egyptian pounds.

Project for control of losses in the Sobat basin and the Machar Marshes

The Sobat River is fed from two main tributaries: the Baro River, which has an average net annual discharge at its confluence with the Sobat of 9.53 billion m3; and the Pibor River, with an average net annual discharge at its confluence with the Sobat of 3.38 billion m3. The Sobat discharges its water in the White Nile at Malakal with an average of 13.7 billion m3 annually. The Machar Marshes lie to the north of the Sobat and are fed from the eastern mountains near the Ethiopian territories through many khors. The amount of water that can be collected from these eastern khors is estimated to be 1.84 billion m3 annually, yet most of this discharge is lost in the swampy area. Moreover, about 2.7 billion m3 is annually lost in this area owing to spilling of water over the banks of the Baro River, where only about 0.5 billion m3 reaches the White Nile to the south of Melut through the Adar River.

Studies are now being carried out for the purpose of minimizing these huge losses in the Machar Marshes by excavating a canal starting from the Baro River at the end of Khor Jakaw, carrying the excess water over and above the capacity of the Baro downstream of the escape of Khor Jakaw. The proposed canal passes in the

-299- swamps and collects on its way the discharges coming from the eastern khors until it discharges in the White Nile at Melut.

The annual water benefit of this project as computed at Aswan is about 3.75 billion m3 and its total cost is about 56 million Egyptian pounds.

Project of long-term storage in the equatorial lakes

Research has shown that in order to optimize the benefits expected from the projects for the control of losses in the Bahr El Gebel and in the Bahr El Zeraf, it is necessary to attain full control of the river discharges entering the sudd area of by means of controlling the discharge from Lake Albert up to the annual mean discharge of Mongalla. This would require long-term storage in Lake Albert. This project will increase the expected water benefit from the Jonglei Canal scheme by not less than 4 billion m3 annually as at Malakal. On the other hand, any proposed storage in the equatorial lakes will necessitate the agreement of the littoral countries concerned.

Project for the development of the capacity of the White Nile

The average maximum discharge of the White Nile at Malakal is about 100 million irrVday, increasing to 120 million in high-flow years. The discharge is expected to increase following completion of the proposed Upper Nile projects mentioned before. Studies have shown that in order to carry these additional discharges, it is necessary to heighten the banks of the White Nile between Malakal and Renk in order to prevent overtopping throughout large areas on both sides of the river, which would cause in turn high evaporation losses.

Conclusions

1. It is strongly recommended that the countries sharing an international river establish a centralized water board with policy-making responsibilities. The national water board should be further responsible for planning the utilization of water resources in the country, carrying out hydrological studies and research, and negotiating the agreements with other co-basin countries for the purpose of developing the shared water resources.

2. It is strongly recommended that developed countries and international organizations provide the financial and technical aid needed for water resources development projects undertaken for the benefit of the countries sharing international rivers. In view of their expected beneficial impact on the standard of living of affected developing countries, the above projects should be given priority over other development projects.

Notes

1/ Text in: United Nations Legislative Series (United Nations publication, Sales No. 63.V.4), p. 143.

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