[8][9] The entire drainage basin of Karsha, formed by the Wadi Khabb Shamsi itself and its numerous tributaries and sub-tributaries, covers an approximate area of 133 km2 (51 sq mi).

Among the different options, three stand out: Having ruled out the second option, due to its lower elevation and shorter length than the third, the remaining two have arguments in their favor to be considered as the source of the Wadi Khabb Shamsi, although in the absence of official maps or an expressed statement by local authorities, the best specialists currently favor the former, and consider that the wadi begins in the Jabal Qihwi / Jebel Qi'wi / Jabal Qa'wah.

Jabal Qihwi has a prominence of 1,435 m (4,708 ft) and a topographic isolation of 23.36 km (14.52 mi),[14] and rises in the central area of the western boundary of the watershed of Karsha / Wadi Khabb Shamsi.

At the end of those first kilometers of the upper course, the wadi begins its middle course with a flow reinforced by the contributions of successive tributaries and characterized by a moderate slope, turning for 3.5 km (2.2 mi) towards the northeast, and then for 1.5 km (0.93 mi) towards the south-southeast, until intercepting, south of the village of Al Hakil, the long dirt track called Wadi Khabb Shamsi Road.

The names of the Wadi Khabb Shamsi (spelled Wādī Khabb Shamsī) and some of its main tributaries were recorded in the documentation and maps prepared between 1950 and 1960 by the British Arabist, cartographer, military officer and diplomat Julian F. Walker,[33] during the work carried out to establish borders between the then called Trucial States, later completed by the United Kingdom Ministry of Defence, on 1:100,000 scale maps published in 1971.