6. The Treaty Regime for the Nile

Brunnée and Toope (2002), p. 122.

Le Floch (2010), p. 475.

Encyclopædia Britannica - Global Edition (2011), p. 5473.

Egypt was administered as an Anglo-Egyptian condominium from 1882 to 1914. In 1914, the United Kingdom proclaimed Egypt a protectorate. It gained its independence in 1922. Encyclopædia Britannica - Global Edition (2011), p. 5112.

Eritrea initially became an Italian colony in 1890, then it came under British military administration in 1941. In 1961, Eritrea was annexed by Ethiopia, which historically considered it part of its territory, and in 1962 incorporated as a province into its territory. After periods of civil war, in 1993, Eritrea became officially independent and was internationally recognized as a state. On the Ethiopian-Eritrean conflict, see Kahsay (2012), pp. 465–467.

Uganda first became a British protectorate in 1894. From 1922 until independence in 1962, it was part of British East Africa. Jennings (2012b), p. 1310.

Kenya became a British protectorate in 1895, a crown colony in 1920, and remained under British colonial rule until its independence in 1963. See Jennings (2012c), p. 645.

Tanganyika (the mainland of today’s Tanzania) became a German protectorate in 1885. Afterwards, its administration was transferred to the United Kingdom, first in 1920 as a League of Nations Mandate and then in 1946 as a United Nations Trust Territory. Present-day Tanzania was created in 1964 through the unification of Tanganyika and Zanzibar, after Tanganyika had gained independence in 1961 and Zanzibar in 1963. Jennings (2012a), p. 1257.

Sudan was administered from 1899 to 1924 as an Anglo-Egyptian condominium and was subsequently still subordinate to Anglo-Egyptian administration until its independence in 1956. See Woodside (2012), p. 1201.

Present-day DR Congo was under Belgian colonial administration from 1879 until independence in 1960. First, in 1879, the Belgian king created the Congo Free State as his personal colony with the consent of the European powers. In 1908, the rule over the country was transferred to the Belgian state until independence in 1960. See Mthembu-Salter (2012), p. 329.

Rwanda and Burundi became part of German East Africa in 1890. After the First World War, they came under Belgian administration, first from 1920 as a League of Nations Mandate and from 1946 as a United Nations Trust Territory. Rwanda and Burundi attained independence in 1962. Clark and Kaufman (2012), p. 993.

Mangu (2011), p. 24.

Check (2011), pp. 85–86.

Waterbury (1979), p. 46; Godana (1985), p. 107.

Check (2011), p. 86.

See Mulira (2010), p. 131.

On the Nile water treaties, see e.g. Degefu (2003), pp. 93–141; Okidi (1994), pp. 323–335; Caponera (1993), pp. 657–659; Godana (1985), pp. 103–121 and 140–157; Wolde-Giorghis (2009), pp. 121–166; Le Floch (2010), pp. 475–486; Wehling (2018), pp. 126–187; among Egyptian commentators, see ‘Abd al-‘Āl (2010), pp. 81–101; ‘Abd al-Wahhāb (2004), pp. 173–179.

Abseno (2009), p. 87; ‘Abd al-‘Āl (2010), p. 126; Kaška (2006), p. 28.

Exchange of Notes Between his Majesty’s Government in the United Kingdom and the Egyptian Government in regard to the Use of the Waters of the River Nile for Irrigation Purposes, 7 May 1929, LNTS XCIII (1929–1930), p. 44 (emphasis added).

Godana (1985), p. 120; Dellapenna (1996), p. 239; ‘Alī Ṭāhā (2005), p. 193.

Tafesse (2011), p. 68.

Protocol between the Governments of Great Britain and Italy for the Demarcation of their respective Spheres of Influence in Eastern Africa, 15 April 1891, BFSP 83 (1890–1891), p. 19, in the original French.

Sudan was not under British colonial administration at the time of the conclusion of the treaty in 1891, so the question of a possible succession of Sudan in respect of the treaty does not arise.

Aide-Mémoire of the Ethiopian Government of 23 September 1957, reproduced in Whiteman, Digest of International Law, U.S. Department of State, Vol. 3, 1964, pp. 1011–1012. Quotation also reproduced at Arsano (2006), p. 343.

For example, Okidi (1994), pp. 323–324; Godana (1985), p. 156.

See e.g. Waterbury (1987), pp. 94–95.

See ‘Abd al-‘Āl (2010), p. 96. To the same effect see Maḥfūẓ Muḥammad (2009), p. 329.

Treaty of Friendship and Commerce between the Kingdom of Italy and the Empire of Ethiopia, signed at the Camp of Uccialli, 2 May 1889. Italian text of the Treaty for the first time published in Atti parlamentari, Documenti Diplomatici, 1889–90, XV, Etiopia, p. 434. English translation of the Italian treaty text reproduced in BFSP 81 (1888–1889), p. 733. The Treaty of Uccialli is also called Treaty of Wichale, after the Amharic version.

English translation of Art. 17, reprinted in BFSP 81 (1888–1889), p. 735. The Italian original reads as follows: “Sua Maestà il Re dei Re d’Etiopia consente di servirsi del Governo di Sua Maestà il Re d’Italia per tutte le trattazioni di affari che avesse con altre potenze o governi.” Emphasis added.

See also Rubenson (1964), pp. 244–251. Protectorates were commonly established by a treaty in which the responsibility for foreign affairs, in particular for the conclusion of international treaties for the protectorate, was transferred to the protector state. See Hoffmann (1997), pp. 1153–1154.

Art. 19 of the Treaty of Uccialli states that the Italian and Amharic texts are equally authentic. The Treaty contains no provision for the case of a divergence between the two texts.

See Rubenson (1964), p. 250, note 36 (emphasis added). In the Amharic text, the Amharic verb for “being possible” is used instead of the binding “consente” in the Italian text, see Elliesie (2008), p. 240.

Letter of Emperor Menelik II to the Italian King of 1890, excerpt reprinted at Rubenson (1964), p. 250.

The conflict over Art. 17 finally led to the Italian-Ethiopian war of 1895. See Rubenson (1964), p. 251.

See Klabbers (1996), pp. 65–66. According to the general principle of intertemporal law, legally relevant facts are generally to be considered according to the law in force at that time, see the Island of Palmas case (Netherlands v. USA), Award of 4 April 1928, pp. 845–846. See also Kotzur (2008); ILC, Doc. A/CONF.39/11/Add.2, p. 42, para. 16.

Under customary international law, codified in Art. 49 of the Vienna Convention on the Law of Treaties, a state may invoke fraud as invalidating its consent to be bound by a treaty if it has been induced to conclude the treaty by the fraudulent conduct of another negotiating state, see ILC, YBILC 1966, Vol. II, pp. 244–245. However, with regard to Art. 17, it was from the outset unclear whether the divergence in substance between the texts had been incorporated deliberately or due to a misunderstanding. The Ethiopian Emperor Menelik II did not understand Italian, while the Italian negotiator Conte Antonelli understood Amharic quite well and is therefore unlikely to have missed the difference between the treaty texts, see Rubenson (1964), pp. 259–264.

Vienna Convention on the Law of Treaties of 23 May 1969, entered into force 27 January 1980, ILM 8 (1969), p. 679.

Intervention of Mr. Tunkin, YBILC 1963, Vol. I, p. 31, para. 42, and p. 33, para. 14. Ultimately however it was concluded that there had been no consent established between the parties and “hence, it could not have been vitiated by fraud or in any other way”, Intervention of Mr. Ago, YBILC 1963, Vol. I, p. 31, para. 49.

For similar conclusion see Rubenson (1964), pp. 280–281.

Drawing the same conclusion are Okidi (1994), pp. 323–324; Godana (1985), p. 156.

See the evidence of authors who assumed that Ethiopia was an Italian protectorate at Rubenson (1964), pp. 252–254.

After the victory of Ethiopia over Italy in the Italian-Ethiopian war of 1895, both countries concluded on 26 October 1896 a peace treaty in which they abrogated the Treaty of Uccialli and Italy recognized the independence of Ethiopia as a sovereign state (Art. III). See Rubenson (1964), p. 251.

See Craven (2007), pp. 147–150.

See Zimmermann and Devaney (2014), pp. 505–506. See also the German Constitutional Court, BVerfGE 96, p. 79, stating that the subject of state succession is “among the most disputed and least secure parts of international law” (“einen der umstrittensten und unsichersten Teile des gesamten Völkerrechts”).

Vienna Convention on Succession of States in respect of Treaties (done on 23 August 1978, entered into force 6 November 1996), ILM 17 (1978), p. 1488; and Vienna Convention on Succession of States in respect of State Property, Archives and Debts (done on 8 April 1983, not yet entered into force), ILM 22 (1983), p. 306.

See Gruber (1986), p. 276. See generally on the two conventions Stern (2000), pp. 133–172.

Hafner and Novak (2012), p. 396; see also Craven (1998), p. 148.

Hafner and Novak (2012), p. 401; see also Craven (1998), pp. 147–148.

McNair (1961), p. 601; Hafner and Novak (2012), p. 401.

See Brownlie (2008), pp. 661–662; Zimmermann (2006), under C., para. 5.

See Art. 16 Vienna Convention on Succession of States in respect of Treaties.

See Art. 2, para. 1(f) Vienna Convention on Succession of States in respect of Treaties.

YBILC 1974, Vol. II, Pt. 1, p. 169, para. 58. Outside of decolonization, however, the Convention is based on the principle of continuity, see Arts. 31, 34 and 35 of the Convention.

This is the term used by the ILC in its commentary to Arts. 11 and 12 of the Draft Articles on Succession of States in respect of Treaties. This category of treaties is also variously described as of a “dispositive”, “real”, or “localized” character. These treaties relate for example to international boundaries, rights of transit on international waterways or over another state’s territory, the use of international rivers, or the demilitarization of particular localities. ILC Commentary to the Draft Articles on Succession of States in respect of Treaties, Official Records of the United Nations Conference on the Succession of States in respect of Treaties, Vol. III, Doc. A/CONF.80/16/Add.2, p. 27, para. 1.

This is demonstrated by the so far uniform state practice. See the ICJ, which stated in its decision in the Gabčíkovo-Nagymaros Project case that Art. 12 of the Vienna Convention reflects customary international law. See also Márquez Carrasco (2000), pp. 511–512; Zimmermann and Devaney (2014), p. 533. For detail on state practice, see Gruber (1986), pp. 260–265.

See Arts. 11 and 12 Vienna Convention on Succession of States in respect of Treaties; and ICJ, Gabčíkovo-Nagymaros Project (Hungary v. Slovakia), Judgment of 25 September 1997, ICJ Reports 1997, pp. 71–72, para. 123. Generally on the difficulty of classifying treaties in the category of territorial treaties, see O’Connell (1979), pp. 735–736.

O’Connell (1967), p. 14. See also Berber (1960), p. 258; Márquez Carrasco (2000), pp. 541–542.

In this sense also O’Connell (1967), pp. 14–15, who pursues the argument that territorial treaties could create or transfer real rights, and “real rights in international law are those which are attached to a territory, and which are in essence valid erga omnes.” The concern of the interests of third parties was also taken up by the ICJ in its decision in the Gabčíkovo-Nagymaros Project case, in which the Court argued in the affirmation of a territorial treaty that the treaty in question “inescapably created a situation in which the interests of other users of the Danube were affected.” ICJ, Gabčíkovo-Nagymaros Project (Hungary v. Slovakia), Judgment of 25 September 1997, ICJ Reports 1997, pp. 71–72, para. 123.

Ethiopia ratified the Convention in 1980, see https://​treaties.​un.​org/​Pages/​ViewDetails.​aspx?​src=​IND&​mtdsg_​no=​XXIII-2&​chapter=​23&​clang=​_​en (accessed 30 April 2019). However, the Convention applies only in respect to the succession of a state which has occurred after the entry into force of the Convention in 1996, see Art. 7, para. 1 of the Convention.

See on the principle of intertemporal law the Island of Palmas case (Netherlands v. USA), Award of 4 April 1928, pp. 845–846. See also the reference to this principle by the ILC, for example in ILC, Doc. A/CONF.39/11/Add.2, p. 42, para. 16.

However, the ILC also took into account the state practice of the nineteenth century when preparing the draft articles on the newly independent states, and the provisions of the Convention largely conform with this older state practice, see the ILC commentary to Art. 15 of the draft articles, ILC Commentary to the Draft Articles on Succession of States in respect of Treaties, Official Records of the United Nations Conference on the Succession of States in respect of Treaties, Vol. III, Doc. A/CONF.80/16/Add.2, pp. 41–44, paras. 3–18. See also Zimmermann (2000), p. 233.

For an overview of state practice from the beginning of the nineteenth century, see O’Connell (1967), passim and Zimmermann (2000), pp. 131–193.

See e.g. McNair (1961), p. 601. Overview of the state practice on territorial treaties at O’Connell (1967), pp. 233–250.

Thus, provisions of a territorial character may continue in force upon state succession, while other provisions of the same treaty do not survive. See the evidence of state practice at ILC, YBILC 1974, Vol. II, Pt. 1, p. 200, paras. 13–15.

To the same effect see Okidi (1994), pp. 323–324; Godana (1985), p. 156.

Thus, the further question of whether Egypt, attaining independence only in 1922, succeeded to the rights and obligations under the treaty as the successor state of the United Kingdom, is not relevant here.

At the time of the conclusion of the 1902 Treaty, Sudan was administered as an Anglo-Egyptian condominium on the basis of the 1899 Condominium Agreement, which does not contain a provision for the representation in Sudan’s foreign affairs. In a condominium, several states exercise territorial sovereignty jointly, so that in case of doubt they can only represent it together. In this sense for example the decision of the Central American Court of Justice in the dispute between Nicaragua and San Salvador 1917, reproduced in AJIL 11 (1917), pp. 674–675. See also Shaw (2003), p. 207. It may be assumed that, when concluding the 1902 Treaty, the United Kingdom tacitly exercised sovereignty over Sudan’s foreign affairs on behalf of Egypt.

Treaty between Great Britain and Ethiopia relative to the Frontiers between the Anglo-Egyptian Sudan, Ethiopia, and Erythroea, 15 May 1902, BFSP 95 (1901–1902), p. 467.

Arsano (2006), p. 340.

Salman (2013), p. 18; Tadesse (2008), p. 7; Le Floch (2010), p. 480.

See e.g. the Egyptian State Information Service (2014).

See also Salman (2013), p. 18; ‘Abd al-‘Āl (2010), p. 97. As early as 1957, the aide-mémoire of the Emperor Haile Selassie of 23 September that year can be understood as implicitly rejecting Ethiopia being bound by Art. III of the 1902 Anglo-Ethiopian Treaty. See also Waterbury (1979), p. 75.

This agreement was intended to settle the dispute over the construction of the dam. It sets out general principles for the construction and operation of the dam, including the principle of cooperation, the principle of equitable and reasonable utilization, and the obligation not to cause significant harm. See the Parts 1, 3, 4 and 9 of the Declaration of Principles on the Grand Ethiopian Renaissance Dam, 23 March 2015, available at State Information Service, https://​www.​sis.​gov.​eg/​Story/​148329/​النهضة-سد-مشروع-حول-المبادئ-إعلان-نص?​lang=​ar (Arabic); English text of the Declaration available at http://​www.​sis.​gov.​eg/​Story/​121609?​lang=​en-us (accessed 28 June 2019).

Degefu (2003), p. 97; Le Floch (2010), p. 481; Tafesse (2011), p. 68.

Wolde-Giorghis (2009), pp. 229–230; Degefu (2003), p. 99. Following similar reasoning Waterbury (1979), p. 75.

Le Floch (2010), p. 481; Woldetsadik (2013), p. 117.

See ‘Abd al-‘Āl (2010), p. 96. Drawing the same conclusion Maḥfūẓ Muḥammad (2009), p. 329.

BFSP 95 (1901–1902), p. 467.

For example, Degefu (2003), p. 97; Le Floch (2010), p. 481; Tafesse (2011), p. 68.

See Island of Palmas case (Netherlands v. USA), Award of 4 April 1928, pp. 845–846; ILC, Doc. A/CONF.39/11/Add.2, p. 42, para. 16. See also Kotzur (2008).

See the ILC commentary to Art. 11, ILC, Draft Articles on the Law of Treaties with commentaries, YBILC 1966, Vol. II, pp. 197–198, paras. 2–7. For example, in 1934, Fitzmaurice stated that ratification was only necessary if the parties had agreed to this, Fitzmaurice (1934), p. 129. McNair, on the other hand, still stated in 1961 that ratification was required unless otherwise agreed by the parties, McNair (1961), p. 133.

This approach was then codified in Art. 14, para. 1 of the Vienna Convention on the Law of Treaties, see the ILC commentary to Art. 11, ILC, Draft Articles on the Law of Treaties with commentaries, YBILC 1966, Vol. II, pp. 197–198, paras. 3–7. Under modern customary law, reflected in Art. 14 of the Convention, ratification is only necessary if the treaty so provides, or if it is otherwise established that the negotiating states agreed that ratification be required. According to this, ratification by Ethiopia would not have been necessary for the conclusion of the 1902 Treaty.

See for example Dellapenna (2006), p. 305; Salman (2013), p. 18; Tadesse (2008), p. 7; Le Floch (2010), p. 480.

See Woldetsadik (2013), p. 58; Tadesse (2008), p. 15.

ICJ, LaGrand Case (Germany v. United States of America), Judgment of 27 June 2001, ICJ Reports 2001, p. 501, para. 99. On the applicability of the interpretation rules laid down in the Convention under customary law, see Gardiner (2012), p. 493.

The Vienna Convention on the Law of Treaties of 1969 is not directly applicable to the Anglo-Ethiopian treaty concluded in 1902, as pursuant to Art. 4 the Convention applies only to treaties which are concluded after its entry into force and, moreover, Ethiopia has not ratified the Convention. For the current status of ratification see https://​treaties.​un.​org/​pages/​ViewDetailsIII.​aspx?​src=​TREATY&​mtdsg_​no=​XXIII-1&​chapter=​23&​Temp=​mtdsg3&​clang=​_​en (accessed 28 April 2019). Nevertheless, the provisions of the Convention may be consulted in so far as they reflect customary international law existing at the relevant time.

See Art. 31, para. 1 Vienna Convention on the Law of Treaties. This provision reflects customary international law. ICJ, Territorial Dispute (Libyan Arab Jamahiriya v. Chad), Judgment, ICJ Reports 1994, pp. 21–22.

ICJ, Case concerning rights of nationals of the United States of America in Morocco, Judgment of 27 August 1952, ICJ Reports 1952, p. 189. See also Fitzmaurice (1957b), pp. 212 and 225–226; Brownlie (2008), p. 633.

See ICJ, Legal Consequences for States of the Continued Presence of South Africa in Namibia, Advisory Opinion, ICJ Reports 1971, p. 31, para. 53.

BFSP 95 (1901–1902), p. 467 (emphasis added). Reproduced in Legislative Texts and Treaty Provisions concerning the Utilization of International Rivers for other Purposes than Navigation, UNLS, ST/LEG/SER.B/12, 1963, p. 116.

Amharic text and its English translation reproduced at Woldetsadik (2013), p. 57 (emphasis added). See also ibid., note 20 for the corresponding translation of the British representative in Addis Ababa from 1928.

See Woldetsadik (2013), p. 75.

The preamble of a treaty forms part of the context and can thus be considered for the interpretation, see Art. 31, para. 2 Vienna Convention on the Law of Treaties and ILC, YBILC 1966, Vol. II, p. 221, para. 13.

The interpretation is to take both into account, together with the context, see Art. 31, para. 3(a) and (b) Vienna Convention on the Law of Treaties.

Declaration of Principles on the Grand Ethiopian Renaissance Dam, 23 March 2015, available at State Information Service, https://​www.​sis.​gov.​eg/​Story/​148329/​النهضة-سد-مشروع-حول-المبادئ-إعلان-نص?​lang=​ar (Arabic); English version available at http://​www.​sis.​gov.​eg/​Story/​121609?​lang=​en-us (accessed 28 June 2019).

See e.g. the Egyptian State Information Service (2014).

See also Art. 31, para. 3(c) Vienna Convention on the Law of Treaties. An earlier draft of the ILC for the interpretation rule stated that the meaning of a treaty text is to be determined “in light of the general rules of international law in force at the time of its conclusion”. This limitation in time was later removed, see the comment by the ILC to Art. 27 of the draft articles (Art. 31 of the Vienna Convention on the Law of Treaties), Doc. A/CONF.39/11/Add.2, p. 42, para. 16.

Similarly the ICJ, which moreover assumes that an international treaty is to be interpreted in an evolutionary way within the framework of the entire legal system prevailing at the time of its interpretation, since the interpretation of the treaty cannot remain unaffected by the subsequent development of law, see ICJ, Legal Consequences for States of the Continued Presence of South Africa in Namibia, Advisory Opinion, ICJ Reports 1971, pp. 31–32, para. 53; ICJ, Aegean Sea Continental Shelf, Judgment, ICJ Reports 1978, pp. 34–35, para. 80.

See also Art. 33, para. 4 Vienna Convention on the Law of Treaties. This norm also reflects customary international law, see ICJ, LaGrand Case (Germany v. United States of America), Judgment of 27 June 2001, ICJ Reports 2001, p. 502, para. 101.

See also Papaux and Samson (2011), pp. 880–881.

Wolde-Giorghis (2009), pp. 229–230; Degefu (2003), p. 99. For similar reasoning see also Waterbury (1979), p. 75: “as it was totally non-reciprocal”.

Peters (2007), para. 5. In the ILC session 1963, Mr. Tunkin proposed to include unequal treaties in the text of the then draft Art. 13 “Treaties void for Illegality” and to define them as “treaties establishing gross inequality between the obligations of the parties”, ILC Summary records of the 15th session, YBILC 1963, Vol. I, p. 69, para. 28.

See ILC Summary records of the 15th session, YBILC 1963, Vol. I, p. 192, para. 37. For detail on the historical evolution of the concept of unequal treaties and the elements of inequality, see Craven (2005), pp. 335–382. On the historical practice, see Peters (2007), paras. 8–22.

See United Nations Conference on the Law of Treaties, First session, Summary records of the plenary meetings and of the meetings of the Committee of the Whole, 1968, UN Doc. A/CONF.39/11, for example p. 280, para. 2; p. 299, para. 57; and p. 379, para. 8.

See also Caflisch (1992), p. 69.

Ibid.

Mr. Jiménez de Aréchaga in the ILC session 1963, ILC Summary records of the 15th session, YBILC 1963, Vol. I, pp. 70–71, paras. 44–45. See also Caflisch (1992), p. 69; Peters (2007), para. 2.

Salman (2013), p. 18; Tadesse (2008), p. 7; Le Floch (2010), p. 480.

The Vienna Convention on Succession of States in respect of Treaties is not applicable to the succession of Sudan in 1956, since Sudan is not a party to the Convention. For the current status of ratification see https://​treaties.​un.​org/​Pages/​ViewDetails.​aspx?​src=​IND&​mtdsg_​no=​XXIII-2&​chapter=​23&​clang=​_​en (accessed 21 April 2019). See generally on the limitations of the Convention with regard to its direct binding effect, the observations and proposals of the Special Rapporteur Francis Vallat, YBILC 1974, Vol. II, Pt. 1, pp. 10–11, paras. 34–41. The clean-slate rule was applicable under customary law for former colonies at the time of the state succession of Sudan in 1956, see for example the award in the dispute between Guinea-Bissau and Senegal over a maritime delimitation, Case concerning the Arbitral Award of 31 July 1989 (Guinea-Bissau v. Senegal), pp. 49–50.

On the customary applicability of the rules on the succession of newly independent states in respect of territorial treaties, see Sect. 6.2.1.2, above.

See Zimmermann (2000), p. 497.

See the evidence of state practice at ILC, YBILC 1974, Vol. II, Pt. 1, p. 200, paras. 13–15.

See ibid., pp. 204–205, paras. 30–31.

Last paragraph of the preamble of the 1902 Anglo-Ethiopian Treaty.

One exception to this is the Exchange of Notes between Egypt and the United Kingdom over the Owen Falls Dam from 1949 to 1953 which was also concluded with the intention of a permanent arrangement. For a detailed discussion of the 1949–1953 Exchange of Notes, see Sect. 6.2.7, below.

For similar conclusion see ‘Abd al-‘Āl (2010), p. 96; Maḥfūẓ Muḥammad (2009), p. 329.

See Zimmermann (2006), under D, para. 4. See also Stern (2000), p. 77. On the rules of international law on separation in general, see Hafner and Novak (2012), pp. 406 and 413–416.

The Vienna Convention on Succession of States in respect of Treaties is not applicable to South Sudan, as it is not a party to the Convention. For the current status of ratification see https://​treaties.​un.​org/​Pages/​ViewDetails.​aspx?​src=​IND&​mtdsg_​no=​XXIII-2&​chapter=​23&​clang=​_​en (accessed 28 April 2019).

For a detailed discussion of the separation of South Sudan and the applicable rules on state succession, see Sect. 6.2.8.3, below.

See for example Africanews (2018).

See ICJ, Fisheries Jurisdiction (Federal Republic of Germany v. Iceland), Judgment of 2 February 1973, ICJ Reports 1973, p. 20, para. 43; ICJ, Gabčíkovo-Nagymaros Project (Hungary v. Slovakia), Judgment of 25 September 1997, ICJ Reports 1997, p. 61, para. 104. See also Shaw and Fournet (2006), p. 2241.

On the conditions under which a change of circumstances may be invoked, see ILC in YBILC 1966, Vol. II, pp. 259–260, paras. 9–13; and Sinclair (1984), pp. 192–193. See also Shaw and Fournet (2006), p. 2251.

See Art. 62, para. 2(a) Vienna Convention on the Law of Treaties.

A proposal of the United States to include such treaties in Art. 62, para. 2(a) of the Vienna Convention on the Law of Treaties was rejected by the majority of states during the negotiations on the Convention, UN Doc. A/CONF.39/11/Add.2, p. 184, para. 543.

See Waldock, Fifth Report, 1966, p. 43, para. 7.

CIA, The World Factbook, Ethiopia, People and Society, https://​www.​cia.​gov/​library/​publications/​the-world-factbook/​geos/​et.​html (accessed 25 April 2019).

See Fitzmaurice, Second Report (1957a), p. 33, para. 2(v): “by the exercise of reasonable foresight”.

Ibid.

On the problem of the wording of Art. 62, para. 1(b) of the Vienna Convention on the Law of Treaties, see Heintschel von Heinegg, who points out that the change of circumstances as such can in fact not affect the scope of the obligations, but rather make the obligations so burdensome that it is unreasonable to insist on their performance. Thus, what is ultimately decisive is whether the further performance of the treaty can in good faith still reasonably be expected from the parties, Heintschel von Heinegg (1992), pp. 292–293. See also Heintschel von Heinegg (2014), p. 466, note 101. To the same effect see Villiger, who stresses in this respect that Art. 62, para. 1(b) of the Convention is ultimately a codified expression of equity and good faith, Villiger (2009), p. 774, note 59.

Waldock, Second Report, YBILC 1963, Vol. II, p. 83, para. 8. See also Brownlie (2008), p. 624.

See Waldock, Second Report, YBILC 1963, Vol. II, p. 85, para. 18. The procedural rules embodied in Art. 65 of the Vienna Convention on the Law of Treaties did not codify existing customary international law, see Prost (2011), pp. 1486–1490. See also the ILC in its commentary to Art. 62 of the draft articles (Art. 65 of the Vienna Convention on the Law of Treaties), YBILC 1966, Vol. II, p. 263, para. 6. However, at least the basic procedural rules of Art. 65 of the Convention, such as notification and negotiations, have, in the meantime, achieved the status of customary law. See Prost (2011), pp. 1486–1490.

Similarly both Le Floch and Woldetsadik, who argue that Ethiopia may terminate the 1902 Treaty on the basis of the doctrine of fundamental change of circumstances, as the Treaty no longer accommodates its needs for water resources development, see Le Floch (2010), p. 481; Woldetsadik (2013), p. 117.

Mthembu-Salter (2012), p. 329.

Here too it can be assumed that the United Kingdom tacitly exercised sovereignty for the foreign affairs of the Anglo-Egyptian condominium Sudan when concluding the treaty. See also Sect. 6.2.2, note 70, above.

Agreement between Great Britain and the Independent State of the Congo, modifying the Agreement signed at Brussels, 12 May 1894, relating to the Spheres of Influence of Great Britain and the Independent State of the Congo in East and Central Africa, 9 May 1906, BFSP 99 (1905–1906), p. 173.

Agreement between Great Britain and His Majesty King Leopold II, Sovereign of the Independent State of the Congo, relating to the Spheres of Influence of Great Britain and the Independent State of the Congo in East and Central Africa, 12 May 1894, BFSP 86 (1893–1894), p. 19.

A succession seems to be supported by Godana (1985), p. 154.

From 1879 to 1908, the territory of the present-day DR Congo was a personal colony of the Belgian king. In 1908, the rule over the country was transferred to the Belgian state until its independence in 1960. See Mthembu-Salter (2012), p. 329.

No devolution agreement has been registered with the General Secretariat of the United Nations, see UN Doc. A/CN.4/150, YBILC 1962, Vol. II, p. 115, para. 68.

See the letter from the Minister for Foreign Affairs of the Congo (Congo-Léopoldville) to the Secretary-General of the United Nations in UN Doc. A/CN.4/150, YBILC 1962, Vol. II, p. 115, paras. 70–71.

Ibid., p. 115, paras. 72–74.

The Vienna Convention on Succession of States in respect of Treaties is not applicable to the state succession of the Republic of the Congo (Congo-Léopoldville) in 1960, as it is not a party to the Convention. For the current status of ratification see https://​treaties.​un.​org/​Pages/​ViewDetails.​aspx?​src=​IND&​mtdsg_​no=​XXIII-2&​chapter=​23&​clang=​_​en (accessed 28 April 2019).

In addition to Art. III, the Agreement also contains provisions on boundary delimitation as well as the construction of a railway and a commercial port. These can be considered separately with regard to the succession of states. See the evidence of some state practice at ILC, YBILC 1974, Vol. II, Pt. 1, p. 200, paras. 13–15.

Exchange of Notes between the United Kingdom and Italy respecting Concessions for a Barrage at Lake Tsana and a Railway across Abyssinia from Eritrea to Italian Somaliland, Rome, 14/20 December 1925, BFSP 121 (1925), p. 805.

Penultimate paragraph of Note No. 2 of the Italian Prime Minister of 20 December 1925, Exchange of Notes between the United Kingdom and Italy respecting Concessions for a Barrage at Lake Tsana and a Railway across Abyssinia from Eritrea to Italian Somaliland, Rome, 14/20 December 1925, BFSP 121 (1925), p. 808.

Quoted at Waterbury (1987), p. 95.

For similar conclusion see Godana (1985), p. 106; Okidi (1982), p. 170; Fahmi (1986), p. 59.

On the customary nature of this rule, see David (2011), pp. 888–889.

The Vienna Convention on the Law of Treaties of 1969 is not directly applicable to the treaty concluded in 1925, as the Convention has no retroactive effect (see Art. 4 of the Convention) and, moreover, Ethiopia is not a party to the Convention. For the current status of ratification see https://​treaties.​un.​org/​pages/​ViewDetailsIII.​aspx?​src=​TREATY&​mtdsg_​no=​XXIII-1&​chapter=​23&​Temp=​mtdsg3&​clang=​_​en (accessed 28 April 2019). Rather, the customary law applicable at the time of the treaty’s conclusion applies, see the Island of Palmas case (Netherlands v. USA), Award of 4 April 1928, pp. 845–846; ILC, Doc. A/CONF.39/11/Add.2, p. 42, para. 16; Kotzur (2008).

See also Art. 35 Vienna Convention on the Law of Treaties. This provision largely reflects customary international law, yet the requirement of an explicit and written acceptance of the obligation did not constitute customary law at the time of the codification of the Convention, Laly-Chevalier (2011), pp. 913–914.

Thus, the controversially discussed question of whether, under customary international law, the consent to a treaty by the third state could be implicit, is not relevant here. On this question, see ILC, UN Doc. A/CN.4/SER.A/1964, YBILC, 1964, Vol. I, pp. 73–80, paras. 4–73, passim; and Laly-Chevalier (2011), p. 911.

Exchange of Notes Between his Majesty’s Government in the United Kingdom and the Egyptian Government in regard to the Use of the Waters of the River Nile for Irrigation Purposes, 7 May 1929, LNTS XCIII (1929–1930), p. 44.

The concrete reason was the planned Gezira Cotton Scheme in Sudan, for which the Nile should be used for irrigation. See ‘Abd al-Wahhāb (2004), pp. 174–175; McCaffrey (2001), p. 237.

Para. 4 of Note No. 2 from Lord Lloyd to Mohamed Mahmoud Pasha of 7 May 1929, LNTS XCIII (1929–1930), p. 116.

Para. 2 of Note No. 1 from Mohamed Mahmoud Pasha to Lord Lloyd of 7 May 1929, LNTS XCIII (1929–1930), p. 44.

Commission Report, para. 88(a), LNTS XCIII (1929–1930), p. 86.

Ibid., para. 88(b)–(e).

See para. 4(b) of the Note from Mohamed Mahmoud Pasha to Lord Lloyd of 7 May 1929: “Save with the previous agreement of the Egyptian Government, no irrigation or power works or measures are to be constructed or taken on the River Nile and its branches, or on the lakes from which it flows, so far as all these are in the Sudan or in countries under British administration, which would, in such manner as to entail any prejudice to the interests of Egypt, either reduce the quantity of water arriving in Egypt, or modify the date of its arrival, or lower its level.” LNTS XCIII (1929–1930), p. 46.

Brunnée and Toope (2002), p. 124; Azarva (2011), p. 467.

In addition, the Agreement granted Egypt the right to carry out any measures necessary for studying and recording the hydrology of the Nile River in Sudan, and to monitor that the distribution of water and the regulation of the Sennar Dam are carried out in accordance with the Agreement, see para. 4(c) and (a) of the Note from Mohamed Mahmoud Pasha to Lord Lloyd of 7 May 1929, reproduced in LNTS XCIII (1929–1930), p. 46.

See e.g. the Egyptian State Information Service (2010).

See Kaška (2006), pp. 25–26; ‘Abd al-Wahhāb (2004), p. 179; Maḥfūẓ Muḥammad (2009), p. 378.

See Maḥfūẓ Muḥammad (2009), p. 389, citing further references, pp. 478–479 and 487.

For example, Mekonnen (2010), p. 435; Mangu (2011), p. 26; apparently also Okidi (1982), p. 182; Peichert (2002), p. 117.

See Godana (1985), p. 142; Lester (1963), pp. 500–501.

Le Floch (2010), p. 479.

Dubuisson (2006), p. 2095.

The Vienna Convention on the Law of Treaties is not directly applicable to the Nile treaties because they were concluded prior to the Convention’s entry into force and not all parties ratified the Convention. For the current status of ratification see https://​treaties.​un.​org/​pages/​ViewDetailsIII.​aspx?​src=​TREATY&​mtdsg_​no=​XXIII-1&​chapter=​23&​Temp=​mtdsg3&​clang=​_​en (accessed 28 April 2019).

See Waldock, United Nations Conference on the Law of Treaties, Official Records, Second Session, 1969, UN Doc. A/CONF.39/11/Add.1, p. 253, para. 41. See also the evidence at Dubuisson who, however, does not consider a comparable degree of concreteness of the provisions necessary, Dubuisson (2011), pp. 1335–1336.

This follows from the reasoning of the PCIJ in the case Compagnie d’électricité de Sofia et de Bulgarie, in which the Court relies primarily on the intention of the parties, PCIJ, Compagnie d’électricité de Sofia et de Bulgarie, arrêt du 4 avril 1939 (exception préliminaire), Série A/B, no 77, p. 76. See also Dubuisson (2006), p. 2099. At the relevant time in 1959, these rules were already customary law, see the above-cited decision of the PCIJ of 1939.

The scope of the 1959 Agreement is broader in that it regulates, for example, the construction of dams and the establishment of a joint technical commission. For a detailed discussion of the content of the Nile Waters Agreement of 1959, see Sect. 6.2.8.1, below.

Sudan took over the 1929 Nile Agreement on attaining independence in 1956, after it had first demanded its repeal or revision. See the writings of Sudanese commentators, for example ‘Alī Ṭāhā (2005), p. 63.

As late as August 1959, the United Kingdom sent a diplomatic note to Egypt, Ethiopia, Sudan, and Belgium as then colonial power of the DR Congo, Burundi, and Rwanda, pointing out that the territories of British East Africa needed more water for their development than they were currently using. It reserved the right to negotiate an additional quota should the need arise and to provide for review of the quota at stated periods. See the Note from the British Embassy in Khartoum, to the Sudanese Ministry of Foreign Affairs, 31 August 1959, reproduced in Whiteman, Digest of International Law, U.S. Department of State, Vol. 3, 1964, p. 1013. See also Waterbury (1979), p. 72.

The Vienna Convention on the Law of Treaties does not provide for the possibility of a tacit termination of an agreement inter se by concluding a later treaty by only some parties to the earlier treaty; this constellation is regulated under the application of successive treaties relating to the same subject matter in Art. 30, para. 4. Insofar as this possibility was not included, the Convention deviates from state practice and does not reflect the state of customary international law. Dubuisson (2006), pp. 2108–2109 and 2111–2112.

Dubuisson (2006), p. 2113.

‘Alī Ṭāhā (2005), pp. 73–74; Maḥfūẓ Muḥammad (2009), p. 329.

See also O’Connell (1967), pp. 246–247.

Likewise in the writings of Sudanese jurists, for example ‘Alī Ṭāhā (2005), p. 73; among Egyptian commentators Maḥfūẓ Muḥammad (2009), p. 329. To the same effect McCaffrey (2007), p. 138; Degefu (2003), p. 130; seemingly also Carroll (2000), p. 280; Le Floch (2010), p. 482.

Para. 3 of Note No. 1 from Mohamed Mahmoud Pasha to Lord Lloyd of 7 May 1929 in conjunction with the Commission Report, para. 89, LNTS XCIII (1929–1930), p. 88.

Orakhelashvili (2011), pp. 774–775.

See Art. 30, para. 4 in conjunction with Art. 30, para. 3 Vienna Convention on the Law of Treaties.

Tanzania was formed in 1964 by the unification of Tanganyika and Zanzibar, after Tanganyika and Zanzibar had attained independence from the British colonial administration in 1961 and 1963, respectively. Under the law of state succession, this was considered as the formation of a new state. See the Articles of Union of Tanganyika and Zanzibar of 22 April 1964, ILM 3 (1964), pp. 763–764. The question of a succession of Tanzania after the unification in 1964 only arises if Tanganyika had succeeded to the rights and obligations under the colonial treaty.

The Vienna Convention on Succession of States in respect of Treaties is not applicable to the state succession of Tanganyika, Kenya, and Uganda in the early 1960s, since none of them is a party to the Convention. For the current status of ratification see https://​treaties.​un.​org/​Pages/​ViewDetails.​aspx?​src=​IND&​mtdsg_​no=​XXIII-2&​chapter=​23&​clang=​_​en (accessed 28 April 2019).

For a detailed discussion of the development of these customary rules, see Sect. 6.2.1.2, above.

On the question of state succession of the newly independent states of East Africa, see Makonnen (1983).

Declaration reproduced in YBILC 1962, Vol. II, para. 127.

Hafner and Novak (2012), p. 409; Maluwa (1999), p. 73; ‘Abd al-‘Āl (2010), p. 97.

Hafner and Novak (2012), p. 410; Maluwa (1999), p. 73. Among the African states, for example, Burundi, Kenya, Malawi, and Uganda followed the approach of Tanganyika and, on attaining their independence, made only slightly modified declarations concerning the continuity of treaties concluded by the colonial powers. See Zimmermann (2000), pp. 159 and 162.

Thus, also the Vienna Convention on Succession of States in respect of Treaties provides that the clean-slate rule applies to newly independent states, see Art. 16 of the Convention. See also Le Floch (2010), p. 477.

Reproduced at Knobelsdorf (2006), p. 632; Azarva (2011), p. 472.

Declarations reproduced at Godana (1985), pp. 150–151. See also Makonnen (1983), pp. 304–305.

Maḥfūẓ Muḥammad (2009), p. 380; Godana (1985), p. 149.

See ‘Abd al-Wahhāb (2004), p. 179; Mekonnen (2010), p. 433.

See ‘Abd al-‘Āl (2010), p. 96; ‘Abd al-Wahhāb (2004), p. 179; Elemam (2010), p. 233.

For a detailed discussion of territorial treaties, see Sect. 6.2.1.2, above. Among Egyptian commentators, it is predominantly assumed that the 1929 Nile Waters Agreement should be regarded as a territorial treaty, see Maḥfūẓ Muḥammad (2009), p. 389, citing further references, pp. 478–479 and 487.

See also Le Floch (2010), pp. 478–479; Godana (1985), pp. 143 and 150.

Commission Report, para. 89, LNTS XCIII (1929–1930), p. 88. See also Le Floch (2010), pp. 478–479.

For similar conclusion see Godana (1985), p. 142; Lester (1963), pp. 500–501.

See e.g. the Egyptian State Information Service (2010).

On the recognition of this principle as customary international law, see ICJ, Fisheries Jurisdiction (Federal Republic of Germany v. Iceland), Judgment of 2 February 1973, ICJ Reports 1973, p. 20, para. 43; ICJ, Gabčíkovo-Nagymaros Project (Hungary v. Slovakia), Judgment of 25 September 1997, ICJ Reports 1997, p. 61, para. 104. See also Shaw and Fournet (2006), p. 2241; Fitzmaurice (2012), p. 612.

See also Art. 62, para. 2(a) Vienna Convention on the Law of Treaties; and the Proceedings of the Committee of the Whole, UN Doc. A/CONF.39/11/Add.2, p. 184, para. 543.

For example Shaw and Fournet (2006), p. 2256.

See Provost (2006), p. 2595.

The ILC excluded the topic of state succession from the scope of its draft articles for the Vienna Convention on the Law of Treaties, as it considered that the topic would be more comprehensively dealt with under the law on the succession of states in respect of treaties. ILC, Report of the International Law Commission on the work of its Eighteenth Session, (1966), UN Doc. A/6309/Rev.1, Vol. II, p. 177, para. 30.

Oeter (1995), pp. 73–74.

For example, O’Connell (1967), p. 146; Zimmermann (2000), p. 798.

In 1969, Iran invoked the end of the colonial era as a fundamental change of circumstances against the Iranian-Iraqi Boundary Treaty and Protocol Concerning the Schatt-al-Arab Waterway of 4 July 1937: “[A]mong the reasons given by the international law for the abrogation of agreements […] is the principle of Rebus Sic Stantibus. […] Considering the principle which has been mentioned, it must be noted that the Frontier Treaty […] was concluded in a time when the British colonial system was at its height of power, and was keeping Iraq under its protecting wings […] At the present time when the period of colonialism has ended and the conditions prevailing in 1316, i.e. the time under which the treaty was signed, have also been changed, the effects and the results emanating from colonialism must also vanish with it.” Reproduced in ILM 8 (1969), pp. 481, 483–484.

On the customary exclusion of treaties establishing a boundary, see Shaw and Fournet (2006), pp. 2242–2244.

The river regime for the Niger River until then resulted from the Congo Act of 1885 and the Treaty of Saint-Germain-en-Laye of 1919.

See ILC, YBILC 1974, Vol. II, Pt. 1, p. 205, para. 32; O’Connell (1967), p. 310.

See Fitzmaurice, Second Report (1957a), p. 33, para. 2(v): “by the exercise of reasonable foresight”.

Ibid.

Similarly Le Floch (2010), p. 479; Woldetsadik (2013), p. 117.

Waldock, Second Report, YBILC 1963, Vol. II, p. 83, para. 8. See also Brownlie (2008), p. 624.

See Waldock, Second Report, YBILC 1963, Vol. II, p. 85, para. 18.

As previously stated, the procedural rules embodied in Art. 65 of the Vienna Convention on the Law of Treaties did not codify existing customary international law, see Prost (2011), pp. 1486–1490. See also the ILC commentary to Art. 62 of the draft articles (Art. 65 of the Vienna Convention on the Law of Treaties), YBILC 1966, Vol. II, p. 263, para. 6. Insofar as the basic procedural rules of Art. 65 of the Convention have today become customary law, this is not relevant with regard to the 1929 Nile Agreement, since the customary international law applicable at the time when the colonial rule ended in the early 1960s applies.

Declaration reproduced at Knobelsdorf (2006), p. 632; Azarva (2011), p. 472.

For detail on Kenya’s position on the 1929 Nile Agreement, see Adar (2011), p. 175. For detail on Uganda’s position on the Agreement, see Mulira (2010), p. 155.

Declaration reproduced at Godana (1985), pp. 150–151. See also Makonnen (1983), pp. 304–305.

On the negotiations on the CFA, see Chap. 8, Sect. 8.​1.

In this case, Tanzania would have succeeded to the rights and obligations under the 1929 Nile Agreement with the unification of Tanganyika and Zanzibar in 1964. The Articles of Union of Tanganyika and Zanzibar contained no provision concerning a continued validity of international treaties of the two states prior to their unification. However, Tanzania declared after the unification in 1964 to continue all international treaties of the predecessor states, limited to the respectively concerned part of its territory: “The United Republic of Tanganyika and Zanzibar declares that […] all international treaties and agreements in force between the Republic of Tanganyika or the People’s Republic of Zanzibar and other States […] remain in force within the regional limits prescribed on their conclusion […].” Declaration reproduced at O’Connell (1967), p. 77. The continuity of the international treaties concluded by Tanganyika or Zanzibar for Tanzania was also accepted by third countries, see the evidence at Mériboute (1984), p. 197.

South Sudan was admitted to the United Nations on 4 July 2011, see UN GA, Admission of the Republic of South Sudan to membership in the United Nations, UN Doc. A/RES/65/308. For Sudan, on the other hand, the question of a succession with respect to the treaties following the separation in 2011 does not arise, as it is deemed identical with the predecessor state and therefore retains its rights and obligations. Generally on the distinction between state continuity and state succession, see Stern (2000), pp. 39–86.

See Sect. 6.2.5.1, above.

See Sect. 6.2.8.3, below.

On the rules on treaties providing for obligations for third states, see Sect. 6.2.4, above. See also David (2011), pp. 888–889; Laly-Chevalier (2011), pp. 913–914.

At the time of the conclusion of the Agreement in 1929, Ethiopia was a sovereign state, Eritrea was an Italian colony, the DR Congo was a Belgian colony while Rwanda and Burundi were a League of Nations Mandate under Belgian administration.

To the same effect Salman (2013), p. 19; Azarva (2011), p. 470; Ayebare (2010), p. 4.

Agreement between the United Kingdom and Belgium regarding Water Rights on the Boundary between Tanganyika and Ruanda-Urundi, London, 22 November 1934, BFSP 139 (1935), pp. 746–747.

See Sect. 6.2.5.2, under “Succession of Tanzania, Kenya, and Uganda”, above.

For similar conclusion see Godana (1985), p. 154.

Note in extracts reproduced at Nkurunziza (2010), p. 16.

For similar conclusion see Godana (1985), p. 155; Le Floch (2010), p. 481.

Declaration in extracts reproduced at Baligira (2010), p. 51.

See for example ibid., p. 51.

Exchange of Notes constituting an agreement regarding the construction of the Owen Falls Dam, Uganda, between the United Kingdom of Great Britain and Northern Ireland and Egypt, 30 and 31 May 1949, UNTS, Vol. 226, p. 273. This exchange of notes is supplemented by three further exchanges, namely the Exchange of Notes constituting an agreement regarding the construction of the Owen Falls Dam, Uganda, between the United Kingdom of Great Britain and Northern Ireland and Egypt, 5 December 1949, UNTS, Vol. 226, p. 280; the Exchange of Notes constituting an agreement regarding co-operation in meteorological and hydrological surveys in certain areas of the Nile Basin, between United Kingdom of Great Britain and Northern Ireland (on behalf of Uganda) and Egypt, 19 January, 28 February and 20 March 1950, UNTS, Vol. 226, p. 287; and the Exchange of Notes constituting an agreement regarding the construction of the Owen Falls Dam in Uganda, between the United Kingdom of Great Britain and Northern Ireland and Egypt, 16 July 1952 and 5 January 1953, UNTS, Vol. 207, p. 277.

Mulira (2010), p. 133.

A devolution agreement has not been registered with the United Nations Secretariat, see UN Doc. A/CN.4/150, YBILC 1962, Vol. II, p. 122, para. 131.

See Sect. 6.2.5.2, under “Succession of Tanzania, Kenya, and Uganda”, above. Declaration reproduced at Godana (1985), pp. 150–151. See also Makonnen (1983), pp. 304–305.

ICJ, Gabčíkovo-Nagymaros Project (Hungary v. Slovakia), Judgment of 25 September 1997, ICJ Reports 1997, p. 71, para. 123.

Ibid., p. 72, para. 123.

Langlands (2012), p. 1309; Mulira (2010), pp. 132–133.

Thus, hydrologists from the Egyptian Ministry of Water Resources and Irrigation are still currently stationed at the Owen Falls Dam to monitor the water level and collect data according to para. 4 of the agreement, see State Information Service (2013).

Same conclusion drawn by Collins (1990), pp. 221–222; Waterbury (1987), p. 96; O’Connell (1967), p. 247, note 5.

The only other noteworthy treaty is a bilateral cooperation agreement concluded by Egypt and Ethiopia on the Nile of 1993, namely the Framework for general co-operation between the Arab Republic of Egypt and Ethiopia, 1 July 1993, http://​www.​fao.​org/​docrep/​W7414B/​w7414b0p.​htm#TopOfPage (accessed 28 June 2019). This agreement contains only a few very generally formulated provisions. Both parties recognize the Nile River and its basin as a “centre of mutual interest” and agree that the use of the Nile waters is to be determined on the basis of the rules and principles of international law, Art. 4. According to Arts. 6 and 7, the parties cooperate in projects that are mutually advantageous. For this purpose, regular consultations are to be provided for. Finally, Art. 8 provides that the two parties are to endeavor to work toward a framework for effective cooperation among all Nile Basin countries so as to promote common interests in the development of the Nile Basin. This 1993 agreement was initially well received; in the intervening period however, it appears that it has not been consistently implemented in practice. See Caponera (1993), pp. 662–663; ‘Abd al-Wahhāb (2004), p. 178; Dellapenna (2006), p. 304.

Agreement between the Republic of the Sudan and the United Arab Republic for the Full Utilization of the Nile Waters, 8 November 1959, UNTS, Vol. 453, p. 51. For a detailed discussion of the genesis and provisions of the Agreement, see ‘Alī Ṭāhā (2005), pp. 55–87.

‘Abd al-Wahhāb (2004), pp. 176–177; Waterbury (1979), p. 74.

Brunnée and Toope (2002), pp. 125–126; Mekonnen (2010), p. 435.

Elemam (2010), p. 233; Ibrahim (2010), p. 199; Taha (2010), p. 214.

‘Abd al-‘Āl (2010), p. 89; Dellapenna (2006), p. 298.

Maḥfūẓ Muḥammad (2009), pp. 374–376.

Taha (2010), p. 214; ‘Abd al-‘Āl (2010), p. 97.

Aide-Mémoire of the Ethiopian Government of 23 September 1957, reproduced in Whiteman, Digest of International Law, U.S. Department of State, Vol. 3, 1964, pp. 1011–1012. Quotation also reproduced at Arsano (2006), p. 343. Already on 6 February 1956, the Ethiopian government had stated in the official Ethiopian daily, The Ethiopian Herald, that Ethiopia reserves its right to use the Nile waters within its territory. Statement of the Imperial Ethiopian Government, Ethiopian Herald, 6 February 1956, in extracts reproduced at Tafesse (2011), p. 73.

See the Note from the British Embassy in Khartoum to the Sudanese Ministry of Foreign Affairs, 31 August 1959, reproduced in Whiteman, Digest of International Law, U.S. Department of State, Vol. 3, 1964, p. 1013. At the same time, the United Kingdom called, unsuccessfully, for the convening of an international conference to determine the rights of the riparian states to the Nile waters and to establish an international Nile River institution, see Waterbury (1979), p. 72.

See also McCaffrey (2001), p. 244; ‘Abd al-‘Āl (2010), p. 88.

Art. 1, paras. 1 and 2 of the 1959 Nile Waters Agreement.

See also Brunnée and Toope (2002), p. 126; Godana (1985), p. 239.

One year after the conclusion of the treaty, Egypt began with the construction of the dam, which was completed in 1971. Mulira (2010), p. 154.

The World Bank had made an agreement between Sudan and Egypt a prerequisite for financing hydraulic projects on the Nile. Only two years after the conclusion of the 1959 Nile Waters Agreement, the World Bank agreed with Sudan a US$32.5-million loan for the Roseires project on the Blue Nile. See Taha (2010), pp. 192 and 195; ‘Alī Ṭāhā (2005), p. 74.

Art. 2, para. 4 of the 1959 Nile Waters Agreement.

Tafesse (2011), p. 71, note 16.

Art. 2, para. 4 of the 1959 Nile Waters Agreement.

Art. 3, para. 1 of the 1959 Nile Waters Agreement.

The Jonglei Canal was initially part of the planned Century Storage project. That project was to increase the amount of water available for irrigation in Egypt and Sudan during the season when the natural river flow of the Nile is low. In addition to the construction of the Jonglei Canal, it provided for the construction of dams at the outflows of Lake Victoria, Lake Albert, and Lake Tana, to permit year-round water storage in these lakes. On the Jonglei project, see Godana (1985), pp. 193–194; ‘Alī Ṭāhā (2005), pp. 46–47.

Kharouf-Gaudig (2012), p. 104. The development of the Jonglei Canal, with over 70 years of research and studies since the beginning of the twentieth century, is one of the most intensively studied major development projects in Africa. Taha (2010), p. 200.

‘Alī Ṭāhā (2005), p. 78; Kharouf-Gaudig (2012), p. 104.

Kharouf-Gaudig (2012), p. 104; Swain (2002), p. 153.

Salman (2011), p. 163; see also Waterbury (2002), pp. 142–144.

It was feared that the Jonglei Canal would negatively affect the ecosystem of the Sudd and the livelihoods of the local population, in particular drinking water, pasture, and fisheries, as well as blocking access to the land on either side of the canal. Salman (2011), p. 163; Godana (1985), p. 196.

UNDP (2010), p. 22; El Zain (2006), p. 143.

In 2008, Egypt and Sudan are said to have agreed on resuming construction and completing the canal, UNDP (2010), p. 22. Since the independence of South Sudan in 2011, however, resuming work on the Jonglei Canal or other water conservation projects in the Sudd region would require the approval of the South Sudanese government.

McCaffrey (2001), p. 243.

‘Alī Ṭāhā (2005), p. 78.

On the PJTC, see Waterbury (1987), p. 97; Ely and Wolman (1967), p. 132.

Arts. 4 and 5 of the 1959 Nile Waters Agreement.

In order to improve basin-wide cooperation, Egypt and Sudan considered extending the PJTC in the late 1970s to include all Nile Basin countries; however, this never happened. See Godana (1985), p. 264; Taha (2010), p. 212.

Collins (1990), pp. 273–274.

Waterbury (1979), p. 74. See also Howell (1994), pp. 98–99.

‘Alī Ṭāhā (2005), p. 79.

Elemam (2010), p. 233.

See e.g. the Egyptian State Information Service (2010).

The Vienna Convention on the Law of Treaties is not directly applicable to the Nile Waters Agreement of 1959, which was concluded before the former’s entry into force, see Art. 4 of the Convention. On the rules on treaties providing for obligations for third states, see Sect. 6.2.4, above. See also David (2011), pp. 888–889; Laly-Chevalier (2011), pp. 913–914.

Ethiopia has been the most vocal in repeatedly rejecting any obligation arising from the 1959 Nile Waters Agreement on the grounds that it is not a party to that treaty. See ‘Alī Ṭāhā (2005), pp. 85–86; Arsano (2010), p. 174; Tafesse (2011), p. 73.

McCaffrey (2001), p. 244; Mekonnen (2010), p. 436; Tafesse (2011), p. 73; Bulto (2009), p. 301; Mangu (2011), p. 27; Degefu (2003), p. 133. See also in the writings of Egyptian commentators for example ‘Abd al-‘Āl (2010), pp. 88–89.

See Office of the President of the Government of Southern Sudan in Collaboration with the Public International Law & Policy Group, South Sudan: a guide to critical post-2011 issues, 2009, https://​de.​scribd.​com/​document/​40343514/​Southern-Sudan-a-guide-to-critical-post-2011-issues (accessed 28 June 2019).

Ibid.

See also the provision of Art. 9, para. 1 Vienna Convention on Succession of States in respect of Treaties.

Available at https://​peacemaker.​un.​org/​node/​1369 (accessed 28 June 2019). For a detailed discussion of the content of the CPA, see Salman (2008), pp. 299–311.

CPA, Chap. II: Power Sharing, signed at Naivasha, 26 May 2004, Schedule A, p. 40, para. 33. Thus, for the transitional period, jurisdiction over the Nile was transferred exclusively to the national government in Khartoum. This may come as a surprise at first glance, since much of the Nile Basin and almost all of its major tributaries are located on the territory of southern Sudan. The fact that the SPLM/SPLA did not insist on having a say in the management of the Nile during the transitional period may partly be due to the fact that the SPLM/SPLA did not want to cause concerns among other Nile riparian states about claims of a future South Sudan to Nile water and thereby complicate or even endanger the separation of South Sudan with the controversial Nile issue. See in more detail Salman (2011), pp. 160–161; Le Floch (2010), pp. 484–485.

Chap. 3, Sect. 2.1 of the CPA.

These topics include issues of nationality, currency, oil fields and production, and oil contracts.

See Mekelle Memorandum of Understanding between the NCP and SPLM on Post-Referendum Issues and Arrangements, 23 June 2010, Mekelle, https://​peacemaker.​un.​org/​sudan-mekelle-memorandum2010 (accessed 28 June 2019). On the rules on water resources in the CPA and in post referendum agreements, see UNDP (2010), pp. 15–16; Salman (2014), pp. 327–332.

A devolution agreement between Sudan and South Sudan as such would also not have any legal effect on Egypt as the other state party to the 1959 Nile Waters Agreement. Rather, it would be necessary that Egypt consents to the devolution of rights and obligations upon South Sudan. This follows from the customary rule pacta tertiis nec nocent nec prosunt which is reflected in Art. 8, para. 1 of the Vienna Convention on Succession of States in respect of Treaties. See generally Zimmermann and Devaney (2014), pp. 536–537.

For the current status of ratification see https://​treaties.​un.​org/​Pages/​ViewDetails.​aspx?​src=​IND&​mtdsg_​no=​XXIII-2&​chapter=​23&​clang=​_​en (accessed 1 May 2019).

For a detailed discussion of Art. 34 of the Convention, see Zimmermann and Devaney (2014), pp. 524–530. Critical on the provision of Art. 34 Craven (1998), p. 158.

See Degan (1996), pp. 222–227; Zimmermann (2006), under F.

For example, Hafner and Novak (2012), pp. 407–408; Zimmermann (2006), under F.; Le Floch (2010), p. 485. In its decision in the Gabčíkovo-Nagymaros Project case, the ICJ explicitly left open the question of the customary application of the provision contained in Art. 34 of the Convention, see ICJ, Gabčíkovo-Nagymaros Project (Hungary v. Slovakia), Judgment of 25 September 1997, ICJ Reports 1997, p. 71, para. 123.

Hafner and Novak (2012), pp. 407–408. For a survey of state practice, distinguishing between the different forms of state succession, see Zimmermann and Devaney (2014), pp. 519–530.

See generally on this question Hafner and Novak (2012), p. 420; Sanchez and Gupta (2011), p. 374.

ICJ, Gabčíkovo-Nagymaros Project (Hungary v. Slovakia), Judgment of 25 September 1997, ICJ Reports 1997, p. 72, para. 123. For a detailed discussion of the decision of the ICJ in the Gabčíkovo-Nagymaros Project case from the point of view of a succession of states in respect of treaties, see Stern (2000), pp. 190–196.

ICJ, Gabčíkovo-Nagymaros Project (Hungary v. Slovakia), Judgment of 25 September 1997, ICJ Reports 1997, p. 71, para. 123.

Ibid., pp. 71–72, para. 123. The concern of the interests of third parties through territorial treaties had already been taken up by O’Connell (1967), pp. 14–15.

ICJ, Gabčíkovo-Nagymaros Project (Hungary v. Slovakia), Judgment of 25 September 1997, ICJ Reports 1997, p. 72, para. 123.

A succession of South Sudan to the rights and obligations under the 1959 Nile Waters Agreement is supported for example by Helal (2013), pp. 981–982.

See ibid., p. 981.

Waterbury (2002), pp. 72–73.

Art. 3, para. 1, first sentence of the 1959 Nile Waters Agreement.

Gruber (1986), pp. 265–268, citing further references; Schachter (1993), pp. 257–258; Zimmermann (2000), p. 21.

See also Zimmermann, who refers to the general obligation of states to settle the questions that arise in the context of the succession by negotiation or any other agreed means of peaceful dispute settlement, Zimmermann (2006), under C., para. 4.

Quoted at Amos (2013); Tigrai Online (2013).

See Sect. 6.2.5.2, under “Succession of Tanzania, Kenya, and Uganda”, above.

See Sect. 6.2.5.3, above.

See also UNDP (2010), pp. 24–25.

See also Sanchez and Gupta (2011), p. 383.

Salman (2014), p. 349.

Le Floch (2010), p. 485.

See also Salman (2011), p. 165, note 5.