{{Short description|Wadi in Oman and UAE}}
{{Infobox river | name = Wadi Hadf | name_native = {{native name|ar|وادي حدف}} | name_other = Wādī Ḩadf | name_etymology = | image = | image_size = 300px | image_caption = | image_alt = Alt text for image | map = | map_size = 300px | map_caption = | map_alt = Alt text for map | pushpin_map = UAE#Persian Gulf#West Asia | pushpin_map_size = 300 | subdivision_type = | subdivision_name = | subdivision_type1 = Country | subdivision_name1 = {{OMN}}<br />{{UAE}} | subdivision_type2 = Governorate <br />Emirate | subdivision_name2 = Al Buraimi<br />{{flag2|Ajman}}<br />{{flag2|Dubai}}
<!---------------------- PHYSICAL CHARACTERISTICS --> | length = {{Convert|27|km|mi|abbr=on}}
<!---------------------- BASIN FEATURES --> | source1 = Northwestern slope of the Um Alnosoor / Jabal Hatta ({{Convert|1280|m|ft|abbr=on}}) | mouth_place = | source1_location = | source1_coordinates= | source1_elevation = {{Convert|1130|m|ft|abbr=on}} (approximately) | mouth = Confluence with the Wadi Hatta, at the Al Khattem Dam, in the enclave of Hatta (Dubai) | mouth_location = | mouth_coordinates = {{coord|24|48|48.2522|N|56|08|30.0876|E|region:AE|display=inline,title}} | mouth_elevation = {{Convert|288|m|ft|abbr=on}} | progression = Wadi. Intermittent flow | river_system = Wadi Hatta | basin_size = {{Convert|548|km2|mi2|abbr=on}} | basin_landmarks = | tributaries_left = Wadi Laim,<ref name="aswad"/><ref name="Masfut"> FO 371/114648 - 1955 Land and sea boundaries of Trucial Sheikhdoms in Persian Gulf - The National Archives, London, England <https://www.agda.ae/en/catalogue/tna/fo/371/114648/n/81></ref> | tributaries_right = Wadi Ghalfa / Gulfa,<ref name="atlas">{{cite book |author=Jāmiʿat al-Imārāt al-ʿArabīyah al-Muttaḥidah|date=1993|title=The national atlas of the United Arab Emirates|url= |location=Al Ain, United Arab Emirates|publisher=United Arab Emirates University with GEOprojects (U.K.) Ltd.|page= |isbn=9780863511004|access-date=}}</ref><ref name="faolist">[https://www.fao.org/aquastat/en/databases/dams Food and Agriculture Organization of the United Nations AQUASTAT - FAO's Global Information System on Water and Agriculture]</ref> Wadi Al Mustab,<ref name="faolist"/> Wadi Al Khulaiban,<ref name="faolist"/> Wadi Lishan, Wadi Hattawi. | custom_label = '''''Custom label''''' }}
'''Wadi Hadf''' ({{langx|ar|وادي حدف|Wādī Ḩadf}})<ref name="aswad"> Trucial States, Muscat and Oman: Aswad - 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/18/1796/n/1></ref><ref>[https://www.mindat.org/feature-288191.html Mindat.org - Wādī Ḩadaf, United Arab Emirates]</ref> is a dry river valley or river valley, with ephemeral or intermittent flow, which flows almost exclusively during the rainy season, located east of the United Arab Emirates, in the enclaves of Masfut (Ajman) and Hatta (Dubai), and north of Oman, in the Al Batinah North Governorate.
It is a left tributary of the Wadi Hatta, to whose extensive {{Convert|548|km2|mi2|abbr=on}} drainage basin it belongs.
== Course ==
The total length of the Wadi Hadf is '''{{Convert|27|km|mi|abbr=on}}''', of which {{Convert|13|km|mi|abbr=on}} run in Omani territory and {{Convert|14|km|mi|abbr=on}} in Emirati territory. Its river source is located at an approximate altitude of {{Convert|1130|m|ft|abbr=on}}, on the northwest slope and a very short distance from the summit of '''Jabal Hatta''',<ref name="tribulus9.2"> Tribulus - Volume 9.2 - 1999 - Journal of the Emirates Natural History Group (pp. 26-28)- A Mountain Wadi that Flows to Both the Arabian Gulf and the Gulf of Oman - Gary R. Feulner - Abu Dhabi, United Arab Emirates, 1999 <https://enhg.org/Portals/1/trib/V09N2/TribulusV09N2Searchable.pdf></ref> also known as Um Alnosoor ({{Convert|1280|m|ft|abbr=on}}).<ref name="aswad"/><ref name="atlas"/>
In its upper and middle course the Wadi Hadf flows from southeast to northwest, crossing the steep mountainous area surrounding Jabal Hatta,<ref>{{Cite web|url=https://es.wikiloc.com/rutas-alpinismo/um-alnosoor-peak-the-mother-of-eagles-jebel-hatta-dubai-22271003|title=Um Alnosoor peak = The Mother of Eagles = Jebel Hatta, Dubai - Albedwawi|website=www.wikiloc.com|language=en|access-date=2024-10-18}}</ref> on both sides of the border between Oman and the United Arab Emirates, until reaching the extensive and rich cultivated area located east of the town of Hadf.<ref>[https://www.mindat.org/feature-288192.html Mindat.org - Ḩadaf, Muḩāfaz̧at al Buraymī, Oman]</ref>
This village, geographically located in the territory of Oman, is administered under an international condominium regime between Oman and the emirate of Ajman.<ref name="Hadf"> FO 371/114648 1955 - Land and sea boundaries of Trucial Sheikhdoms in Persian Gulf - The National Archives, London, England <https://www.agda.ae/en/catalogue/tna/fo/371/114648/n/82></ref><ref>{{cite web |publisher=web.archive.org |title=The Basement Geographer Scattershot slices of the world - International Condominiums - Hadf (Oman/United Arab Emirates) |url=http://basementgeographer.com/international-condominiums/ |access-date=2024-10-07 |archive-date=2013-08-27 |archive-url=https://web.archive.org/web/20130827215856/http://basementgeographer.com/international-condominiums/ |url-status=bot: unknown }}</ref>
At that point the Wadi Hadf turns northeast towards the ''Sinadil Pass'' through a narrow, steep-sided gorge cut mainly through cemented gravel deposits. However, just above the head of the gorge, the wadi forms a effluent or distributary channel branching off from the main channel and running northwards.<ref name="tribulus9.2"/>
thumb|left| Course chart and elevation profile of Wadi Hadf - Oman and UAE
This second channel is much less visible than the main wadi gorge, because it is shallower and is densely vegetated and used for agricultural crops, but a kilometre downstream of its formation it becomes a complete and well-defined wadi, flowing into the large alluvial plain of Madam ''(Madam Plain)'',<ref name="MadamPlain1"> FCO 8/863 1968 - Harbour development and water survey - The National Archives, London, England <https://www.agda.ae/en/catalogue/tna/fco/8/863/n/478></ref><ref name="MadamPlain2"> FO 1016/840 1965 Jan 01 - 1965 Dec 31 - Trucial States: water resources; with hydrological and groundwater survey - The National Archives, London, England <https://www.agda.ae/en/catalogue/tna/fo/1016/840/n/188></ref> where it is grouped with other important wadis that drain the western flank of the Hajar Mountains, forming the Wadi Fayah, which once flowed into the Persian Gulf, in the area of the border between Sharjah and Ajman.<ref name="tribulus9.2"/>
The fact that this effluent channel drains into a catchment area (Persian Gulf) opposite that of the main wadi (Gulf of Oman), makes the Wadi Hadf a truly rare and exceptional case, which is made possible by the fact that the place where the wadi emerges from the mountains, with a considerable flow in the event of heavy rains, coincides precisely with the imperceptible drainage divide between the basins of the Persian Gulf and the Gulf of Oman, occasionally allowing the distribution of the water flow. However, due to the scarcity of rainfall, this second channel is currently only active as an overflow channel after a period of torrential rains.<ref name="tribulus9.2"/>
At the exit of the spectacular gorge formed by the main channel of Wadi Hadf as it passes through Hadf and Sinadil, the wadi heads northeast across the international dividing line between Oman and the United Arab Emirates, and enters the enclave of Masfut, crossing the great gravel plain of Sayh Muzayri' / Sayḩ Muḑayrah, leaving to the north the urban area of '''Mudayrah''' / Muzairah / Muzayri', with its neighborhood of Sayh Al Zahra, and the catchment basin and waterways that flow into the Persian Gulf.
thumb|left|Wadi Hadf (tributary of Wadi Hatta), at the mouth of Wadi Laim, Hatta, Dubai
Upon meeting the natural barrier formed by the mountain ridge of '''Jabal al Abyad''' / Jabal al Bayd {{Convert|559|m|ft|abbr=on}},<ref name="atlas"/> right at the place occupied by the '''Hadf Dam''' dam and reservoir, the wadi turns east-southeast, crossing the old town and current city of Masfut, which concentrates some of its most representative historical buildings (castle and current museum, watchtowers and mosques).<ref>{{cite web |publisher=visit-ajman.ae|title=Visit Ajman - Department of Tourism - Digital map of Masfut |url=https://digitalmap.ajmantourism.ae/masfout.html|access-date=2024-10-07}}</ref>
Still in the Masfut enclave, and before continuing its course towards the confluence with the Wadi Hatta, the Wadi Hadf receives on its right the mouth of its tributaries Wadi Gulfa / Ghalfa, Wadi Al Mustab, Wadi Al Khulaiban and Wadi Lishan.
In the territory of the Hatta enclave (Dubai), one and a half kilometers before the ''Al Khattem Dam'', where it joins the Wadi Hatta, the Wadi Hadf receives the waters of its last two tributaries: on the right, the Wadi Hattawi, and on the left, the Wadi Laim.<ref name="atlas"/>
== Dams and reservoirs ==
Like other regions in the UAE, the Wadi Hadf geographical area has occasionally been affected by unusually heavy rainfall and flooding.<ref>{{Cite news|url=https://gulfnews.com/uae/weather/ajman-police-rescued-residents-and-multiple-vehicles-from-floods-1.1688205|title=Ajman Police rescued residents and multiple vehicles from floods. Police urge residents to take precautions during unstable weather - Aghaddir Ali, Staff Reporter, 2016|website=gulfnews.com|language=en|access-date=2024-10-07}}</ref>
To prevent the risk of flash floods and increase the potential for groundwater recharge, a 11-metre-high dam with a reservoir area of 1.02 km² and a capacity of 3 million cubic metres, officially named '''Hadf Dam''' (coordinates: 24°49′38″N, 56°4′34″E), was built in 1991 on the Wadi Hadf river in the emirate of Ajman,<ref name="faolist"/><ref name="MOB"> Ministry of Energy and Infrastructure in UAE - Federal Dams https://admin.bayanat.ae/Home/DatasetInfo?dID=lFWr8jmvtTwdCtQd7uDtLjOq-EB6rfmemu-OtkcDuCo&langKey=en></ref> although some media refer to it as ''Al Owais Dam''.<ref>{{Cite news|url=https://www.tawyeen.com/tword/?p=20509|title=Citizens of Fujairah and the Eastern Region: Owais Dam expansion revives hundreds of rainfed farms in the emirate - Hamid bin Qaddour Al-Yamahi, 2012{{!}} |website=www.tawyeen.com|language=ar|access-date=2024-09-17}}</ref><ref>{{Cite news|url=https://www.khaleejtimes.com/article/work-on-increasing-dams-capacity-to-begin-soon|title=Work on increasing dam’s capacity to begin soon - 2012{{!}} |website=www.khaleejtimes.com|language=en|access-date=2024-09-19}}</ref>
Also in the emirate of Ajman, two other smaller dams were built in 2002, in the wadis Al Mustab and Khulaiban, both tributaries of the Wadi Hadf: '''Al Mustab Dam''', 10.5 metres high, with a reservoir of 0.0035 km² and a capacity of 0.0175 million cubic meters (coordinates: 24°48′50″N, 56°5′16″E); and the 7-metre-high '''Al Khulaiban Dam''', with a reservoir of 0.0036 km² and a capacity of 0.0184 million cubic metres (coordinates: 24°48′37″N, 56°5′34″E).<ref name="faolist"/><ref name="MOB"/>
A second dam was built in 2004 on the same Wadi Hadf riverbed, officially called the '''Muzaira'a Dam''', 11 metres high, with a reservoir of 0.028 km² and a capacity of 0.0485 million cubic metres (coordinates: 24°49′5″N, 56°2′53″E).<ref name="faolist"/>
Finally, already in the territory of the Hatta enclave (Dubai), another large dam called '''Al Ghabra Dam''' was built, located at the coordinates: 24°47′44″N, 56°6′36″E, shortly after the confluence of the Wadi al Amed / Wadi Amid with the Wadi Hattawi (tributary of the Wadi Hadf).<ref name="Ramsar-Hatta"> Ramsar Information Sheet - Hatta Mountain Reserve - 2019 <https://rsis.ramsar.org/es/ris/2368?language=es></ref><ref name="Qawr-Hatta"> FCO 18/1978 1958 Sketch map drawn by Julian Walker for boundary delimitation: Wadi Al Qawr and Wadi Hatta - The National Archives, London, England <https://www.agda.ae/en/catalogue/tna/fco/18/1978/n/1></ref>
== Toponymy == Alternative names: Wadi Hadaf, Wadi Hadf, Wādī Ḥadaf, Wādī Ḩadaf, Wādī Ḩadf.
The name of Wadi Hadf (spelled Wādī Ḩadf), its tributaries, mountains and nearby towns was recorded in the documentation and maps produced between 1950 and 1960 by the British Arabist, cartographer, military officer and diplomat Julian F. Walker, during the work carried out to establish the borders between the then called Trucial States,<ref name="Qawr-Hatta"/> and later completed by the Ministry of Defence of the United Kingdom, on scale maps 1:100,000 published in 1971.<ref name="aswad"/>
== Population ==
The Wadi Hadf area was mainly populated by the Biduwat tribe.<ref name="tribusagda114648"> FO 371/114648 - 1955 Land and sea boundaries of Trucial Sheikhdoms in Persian Gulf - The National Archives, London, England <https://www.agda. ae/en/catalogue/tna/fo/371/114648/n/130></ref><ref name="tribuscooast"> FO 371/132894 1958 Tribes of Trucial States coast - The National Archives, London, England <https://www.agda.ae/en/catalogue/tna/fo/371/132894/n/94</ref><ref name="lorimerhatta">Gazetteer of the Persian Gulf. Vol. II. Geographical and Statistical. J G Lorimer. 1908', British Library: India Office Records and Private Papers, IOR/L/PS/20/C91/4, in Qatar Digital Library <https://www.qdl.qa/en/archive/81055/vdc_100023515714.0x000094></ref>
== See also ==
* Wadi Hatta * 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 == {{reflist}}
== External links == {{commons category-inline|Wadi Hadf}}
{{Authority control}} {{DEFAULTSORT:Hadf, Wadi}}
Category:Wadis of the Emirate of Dubai Category:Wadis of United Arab Emirates Category:Valleys of United Arab Emirates Category:Wadis of Oman Category:Rivers of Oman Category:Wadis of the Emirate of Ajman Category:Hatta, United Arab Emirates