Is it permissible to combine prayers while traveling, even if water is available?

Be aware that combining prayers is a concession granted for travel that permits shortening prayers, and it has no relation to the presence or absence of water. A traveler may combine two prayers, either by advancing them (taqdim) or delaying them (ta'khir), whether he finds water and performs ablution (wudu') or does not find it and performs dry ablution (tayammum). It has been reported that the Prophet, peace and blessings be upon him, used to combine prayers during the Battle of Tabuk.