Surrounded by massive sand dunes, Khawr al Udayd is an inlet of the Persian Gulf in the southeast of Qatar. It is known to local English speakers as the "Inland Sea." The Khor Al-Adaid area, also known regionally as the ‘Inland Sea', is located in the south-east of the State of Qatar. The area presents a remarkable landscape formed by a globally unique combination of geological and geomorphological features. These features themselves create a diverse scenery of exceptional, undeveloped natural beauty, in what remains predominantly a ‘wilderness area'. Each landscape unit on its own, notably the Persian Gulf, large mobile dunes, the tidal embayment system, inland and coastal sabkha, recently discovered "salt hummocks", stony deserts, elevated mesas and rocky outcrops, as well as the transition between each of them, contribute to the unique character of Qatar's southern territory. This intrinsic attractiveness, of a largely uninhabited area, is added to by the presence of a diverse native terrestrial flora and fauna alongside a varied and sensitive marine ecosystem. The flora present in the area is typical of those habitats represented and supports species and communities mostly widespread on the Arabian Peninsula, yet not occurring in the same combination in any other single locality. The fauna includes several species which are internationally rare and/or threatened, for example Dugong and Turtles, with populations of certain species of bird being of national and regional importance, e.g. long-distance migrant waterfowl winter, and regionally declining breeding species also resident, including Ospreys nesting on islets. Terrestrial areas continue to support Arabian Gazelles, while there are plans to reintroduce Arabian Oryx within the hinterland of Khor al-Adaid.
There is no similar assemblage of terrestrial and marine environments, with a large tidal embayment lying within an area of mobile dunes, and of sabkhat systems, anywhere else in the world. This assemblage depends on the significant continuation of ongoing processes in the development of landforms. These geological and geomorphological processes cannot be observed and studied in this juxtaposition elsewhere in the world. The interaction of processes and the appearance of sabkha ecosystems and salt hummocks were identified by international interdisciplinary experts as an area of global importance (Barth et al. 2005).
The varied ecosystem of Khor Al-Adaid is of international scientific interest and shows remarkable adaptations to the extreme environmental conditions: limited rainfall, very high seawater temperatures in summer (up to and occasionally more than 33°C.), very low sea temperatures in winter and high salinity. The location of Khor Al-Adaid coral communities is predicted by Sheppard (2003) to have the greatest temperature range within the Persian Gulf. Phillips (2003) adjudged the seagrass beds, extending from Bahrain down the East coast of Qatar and along the coast of the United Arab Emirates, as being one the most productive in the world and as important feeding grounds for endangered species including turtles and dugongs.
A nomination on the Natural World Heritage list would be the first one in the State of Qatar and the second on the Arabian Peninsula. The IUCN Advisory Body evaluated a nomination file for the Hawar archipelago, Kingdom of Bahrain, and called for the establishment of a coastal Natural World Heritage Site with neighbouring countries which have a shared responsibility for the islands and surrounding waters.
The area is the scene of outstanding examples of significant on-going processes in the development of landforms. The sabkha flats, salt-crusted desert extending from the Khor up to Mesaieed is different from the classic sabkhas, which are composed of calcium carbonate and derived from the sea. That in the Khor Al-Adaid area has built eastward by quartz sand being delivered from dunes by the dominant north-northwest shamal winds. In turn more sand dunes traverse this flat surface into the sea and are thus continually prograding the sabkha in a seaward direction. Nowhere else in the world can this rapid process of sabkha formation be observed and studied. There is a finite source of sand, and it is ultimately foreseeable that all the available supplies will have reached the sea and the sabkha system will stop expanding. This is why this on-going process is of considerable importance. The pisolites found in the area - coated shells with calcium carbonate precipitation - are the only ones known to exist in a matrix of quartz sand. In addition, the hyper-saline ground waters in the more landward parts of this sabkha contain very young primary dolomite crystals. Dolomite is common in ancient limestones, but this is one of the few areas in the world where it is presently actively precipitating beneath the surface around quartz sand. This sabkha is therefore a unique place for field studies of the chemical processes that form this mineral, which remains one of the largely unsolved mysteries of modern geology. In addition, the area comprises a large number of recently discovered "salt hummocks". Each of these hummocks or mounds is covered by a salt and gypsum crust, which may represent a former sabkha surface, corresponding with a former sea level. In this case it would be a strong indication of post-Pleistocene to late Holocene sea level fluctuations. Raised beaches here also attest to this phenomenon. Lastly, the area is the scene of progressive filling-in of the lagoon, as can be inferred from satellite images. Tidal currents keep it open near the entrance today, but if the shallow marine areas farther inland are filled, tidal currents would diminish and the rest of the inland sea might accrete entirely. Examining the satellite images in the vicinity of Umm Said (Mesaieed) shows an area that may, in the past, have been similar to Khor Al-Adaid. The Khor Al-Adaid area provides an instructive outdoor classroom for presently active geological and geomorphological processes, which, indeed, already attract national and international visitors, including both ‘sight-seeing' tourists and academics.
