Wadi Nahela (), also known as Wādī Ghēl, Wadi Ghil, Wadi Nahail, Wadi Nahala, Wadi Nehaila or Wadi Nuhaila,FCO 18/1969 - 1959 - Sketch map drawn by Julian Walker for boundary delimitation: Dibba - The National Archives, London, England <https://www.agda.ae/en/catalogue/tna/fco/18/1969> is a dry valley or river with intermittent flow, which flows almost exclusively during the rainy season, located at the northeast of the United Arab Emirates, in the Emirate of Ras Al Khaimah.

It forms its own drainage basin, which has an approximate area of , Al-Farraj, Asma & Harvey, Adrian. (2004). Late Quaternary interactions between aeolian and fluvial processes: A case study in the northern UAE. Journal of Arid Environments. 56. 235–248. 10.1016/S0140-1963(03)00054-5. <https://www.researchgate.net/publication/256941317_Late_Quaternary_interactions_between_aeolian_and_fluvial_processes_A_case_study_in_the_northern_UAE> and is limited to the north and northeast by the Wadi Naqab hydrographic basin; to the east with the Wadi Kiriba;Mindat.org - Wādī Kirībā, Ra’s al Khaymah, United Arab Emirates to the southeast with the Wadi Tawiyean basin;Mindat.org - Ţawīyayn, Al Fujayrah, United Arab Emirates to the southwest with minor wadis that pour their waters into the great alluvial plain of Jiri plain, Trucial States: water resources; with hydrological and groundwater survey - Ref. FO 1016/840 - 1965 - The National Archives, London, England <https://www.agda.ae/en/catalogue/tna/fo/1016/840/n/184> near the town of Khatt; and to the west with the same plain, into which it flows. Application of a hydrological model in a data poor arid region catchment: a case study of Wadi Ham - Mohamed Mustafa Al Mulla PhD Thesis Academic Year 2005-2006 - Supervisor: Dr Ian P. Holman - December 1, 2005 - Cranfield University at Silsoe - Institute of Water and Environment <https://dspace.lib.cranfield.ac.uk/bitstream/handle/1826/3061/Mohamed%20Al%20Mulla%20Thesis%202005.pdf?sequence=1&isAllowed=y>

Almost all this hydrographic basin is in the Emirate of Ras Al Khaimah. Only a small portion of south of the basin belongs to the Emirate of Fujairah.

The highest point is located at the eastern end, at the top of Jabal Harf (), on whose western slope the Wadi Baqal originates, Map of Trucial States, Muscat and Oman - Rams - Scale 1:100 000 - Published by D Survey, Ministry of Defence, United Kingdom (1971) - Edition 3-GSGS - The National Archives, London, England <https://www.agda.ae/en/catalogue/tna/fco/18/1785>Mindat.org - Wādī Baqal, Ra’s al Khaymah, United Arab Emirates and other important tributaries and sub-tributaries of the Wadi Nahela.

The most prominent towns in the Wadi Nahela watershed are BaqalMindat.org - Baqal, Ra’s al Khaymah, United Arab Emirates and Tala, although there are other small villages and farms scattered around, most of them without permanent inhabitants.

Course

The source of the main channel of the Wadi Nahela is located approximately at an altitude of , at a point equidistant between Jabal Ash Sharaf and Aqbat Al Kibs , very close to the line of territorial demarcation between the emirates of Emirate of Ras Al Khaimah and Fujaira, to the southeast of the drainage basin.

In the first kilometer and a half from its source, the Wadi Nahela has a very steep slope, typical of a torrent in its upper course, losing more than of elevation in that short interval.

From that point on, the wadi moderates its slope. It follows a layout typical of a middle course, receiving on the right the confluence of an important tributary that begins its course on the western slope of the Jabal Harf and the Wadi Baqal.

Seven hundred meters after the mouth of the Wadi Baqal, we can find on the left bank of the wadi the ruins of an older settlement, with the usual dry stone constructions, and almost at the end of the middle course, the confluence of a small tributary wadi, also on the right, very popular among hikers because its channel leads to an area with picturesque caves, known as Baqal Caves.

At the beginning of the lower course of the Wadi Nahela, at the point where the current channel of the wadi turns towards the northwest, a small dam was built in 1986, intended to feed underground water resources and reduce damage from possible floods, which receives the name of Wadi Nahela Breaker (Arabic: حاجز وادي نحيله‎). Ministry of Energy and Infrastructure in UAE - Federal Dams https://admin.bayanat.ae/Home/DatasetInfo?dID=lFWr8jmvtTwdCtQd7uDtLjOq-EB6rfmemu-OtkcDuCo&langKey=en>

During the first kilometer and a half of the route, after the dam, the Wadi Nahela follows a well-defined channel with a bed of boulders and sides of sedimentary materials eroded by water. Afterward, the wadi channel loses definition and is progressively integrated into the Jiri plain, Trucial States: water resources; with hydrological and groundwater survey - Ref. FO 1016/840 - 1965 - The National Archives, London, England <https://www.agda.ae/en/catalogue/tna/fo/1016/840/n/184> forming an alluvial fan. Its sides lose height, and sporadically, it widens considerably and divides into successive forks.

Each new bifurcation distributes the potential waters and the resulting arms lose flow and intensity, so the new channels also lose definition, making it very difficult to determine which is the main arm, especially because, as usually happens in other alluvial plains of similar morphology, over time, the wadi´s current can also wander between torrential rains and others, greatly altering the previous courses, which nevertheless maintain their mark on the plain.

Towards the middle of its lower course, shortly before its mouth, the Wadi Nahela receives on the left the confluence of two other important tributaries: the Wādī Diwе̄rah (identified on older maps as Wadi Duwaira) and the Wādī Al Mawārid (also known as Wadi Muwarid).

Toponymy

Alternative names: Wādī Ghēl, Wadi Ghil, Wadi Nahail,FO 371/140223 - 1959 - Relations between rulers of Trucial States and Petroleum Development Trucial Coast Company. Code BA file 1531 (papers 1 to 11) - The National Archives, London, England <https://www.agda.ae/en/catalogue/tna/fo/371/140223/n/65> Wadi Nahala, Wadi Nehaila, Wadi Nuhaila, Wādī Nḥīlh.

In the National Atlas of the United Arab Emirates it appears with the spelling Wādī Ghēl.

The names of Wadi Nahela (spelled Wadi Nahail) and its tributary Wadi Baqal were recorded in the documentation and maps prepared between 1950 and 1960 by the British Arabist, cartographer, military officer and diplomat Julian F. Walker, during the work carried out to establish borders between the then so-called Trucial States, later completed by the United Kingdom Ministry of Defence, on 1:100,000 scale maps published in 1971.

Population

The entire area near the Wadi Nahela and its tributaries was populated by the Habus tribe,Tribes of Trucial States coast - 1958- Ref. FO 371/132894 <https://www.agda.ae/en/catalogue/tna/fo/371/132894/n/43>Al Ḩabūs, Umm al Qaywayn, United Arab Emirates distributed between the tribal areas of Bani Idaid,Mindat.org - Banī ‘Udayd, Ra’s al Khaymah, United Arab Emirates Banī ḨasanMindat.org - Banī Ḩasan, Ra’s al Khaymah, United Arab Emirates and Banī Rayyil.Mindat.org - Banī Rayyil, Ra’s al Khaymah, United Arab Emirates

See also List of wadis of the United Arab Emirates List of mountains in the United Arab Emirates List of wadis of Oman List of mountains in Oman

References

External links

Traventure Talks - Caves of Baqal-Nahela - 2022 (YouTube)