The slope gradient, from flat to steep, affects water inundation during extreme rainfall. Typically, water flows from higher to lower elevations, meaning slope gradient influences runoff and infiltration. Low-elevation flat areas are more quickly flooded than high-elevation or steep-sloped areas. Naturally, low slopes and elevations are highly weighted as flood-prone zones. Steep slopes significantly affect rainfall runoff response; excess rainfall quickly generates higher peak discharge because less water infiltrates the soil, causing rivers to overflow with strong currents. Conversely, flat slopes tend to absorb rainfall more slowly. Bahorok District is an area characterized by relatively steep slopes.

Flood vulnerability is influenced by several factors, including slope gradient, land use, rainfall, river flow, as well as meteorological factors (rainfall intensity, distribution, frequency, and duration) and watershed characteristics (land elevation, soil texture, and landform). Flood-prone areas are spread across several villages in Bahorok District. Three villages categorized as flood-prone to highly flood-prone are Lau Damak Village (1,786.23 ha), Batu Jong-jong Village (1,287.71 ha), followed by Timbanglawang Village, Bungara Plantation, and Ujung Bandar Village. Theoretically, flood hazards are not only related to land cover but also to rainfall, soil texture, landform, slope gradient, and river proximity. Most flood-prone areas are located near river channels.