The River Vartry is a river in the Republic of Ireland. It rises in Calary Bog under the Great Sugar Loaf mountain in north County Wicklow. In 1861 Parliament passed the Dublin Waterworks Act creating the project to dam the River Vartry in Roundwood to form the Vartry Reservoir. This was completed in 1865 and was the first clean source of water for Dublin, replacing the canal water. There are several references to the Vartry in James Joyce's Ulysses, "… and on his expressed desire for some beverage to drink Mr Bloom in view of the hour it was and there being no pump of Vartry water available for their ablutions let alone drinking purposes...” or “Power. Particular about his drink. Flaw in the glass, fresh Vartry water.” This reservoir still supplies 40% of all of Dublin's water needs.