*3.4. Aspect*

The front-facing side of a slope, or generally the face of the slope, is defined as the aspect [109]. When combined with the slope and slope length maps, the aspect can indicate the extension of a particular slope in a specified direction to unveil the potential flow of groundwater [70]. The aspect proceeded by flat surfaces or gentle slopes allows the precipitated water to flow smoothly and streamlined, thereby maximizing the area's infiltration capacity, leading to greater recharge [70,109]. Islamabad is composed of higher elevations at the northern outskirt that stretches predominantly towards the east. The aspect is proceeded by the gentle and flat surfaces containing the residential zone of Islamabad. The aspect can indicate the flow of precipitation and groundwater accumulation towards the inner zones in Islamabad. Therefore, it is used as a key factor in the current study.
