This stone channel, at the food of Mount Arafat, are the remains of what used to be part of the Canal of Zubaidah. The canal was commissioned by the Abbasid queen Zubaidah bint Ja’far in the early 9th century to provide water for pilgrims. It is also known as the ‘Nehr Zubaidah’.
Featured image: https://welcomesaudi.com/activity/ain-zubaidah-makkah