Ibn Muslim (may Allah have mercy on him) said: Abu Amr al-Awza'i (may Allah have mercy on him) was asked: "The time of the prayer has come and the water is away from the road; is it obligatory on me to turn aside from the road and go to it?" He said: Musa bin Yasar (may Allah have mercy on him) narrated to me from Nafi' (may Allah have mercy on him), and Nafi' (may Allah have mercy on him) from Ibn Umar (may Allah be pleased with him), that he would be on a journey and the time of the prayer would come while water was one or two bow-shots (ghalwah) away from him, or about that, and then he would not turn aside to it.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 1104