It was narrated from Ibn 'Abbas (رضي الله عنه) that

Ibraheem brought Isma'eel and Hajar, and left them in Makkah at the site of Zamzam…. and he narrated the hadeeth. Then she came from al-Marwah to Isma’eel, and the spring had begun to flow. She started digging with her hands around the spring, to make a hole so that the water would gather in this hole, then she took her jug and scooped up some water into her waterskin. The Messenger of Allah (ﷺ) said: “May Allah have mercy on her; if she had left it alone it would have been a spring flowing (on the surface) until the Day of Resurrection.”