Window like apertures such as this one discovered in the eastern wall of the Siloam Channel near Area B (see plan), were part of an ingenious irrigation system. Other apertures were cut on the western side of the channel to catch rain flowing down the slope of the hill. The apertures on the east, or downhill, side could be blocked or opened to divert water from the channel to agricultural plots in the Kidron Valley.
The Siloam Channel also provided a conduit for water from the Gihon Spring to reservoirs at the southern end of the City of David.