Grade 12 Geography: Fluvial Processes, River Capture, Rejuvenation, and GIS

Comprehensive vocabulary flashcards covering the key geomorphology concepts (river capture, headward erosion, river rejuvenation, associated landforms) and mapwork/GIS concepts from the Grade 12 Geography lecture.

Stream Piracy / River Capture

Occurs when a river that has gained more energy captures or intercepts the headwaters of another river with lesser energy.

Abstraction

The lowering and shifting of the watershed, causing one drainage basin to expand at the expense of another.

Headward Erosion

Erosion that takes place towards the source of a river (backwards), lengthening the river course as it cuts back into the source area.

Captor River

The energetic stream that cuts back by headward erosion and intercepts or takes the water of another river.

Captured River

The river which has its headwaters intercepted or taken by the captor river.

Misfit Stream

The river that has lost its source water as a result of river capture (also called the beheaded stream), becoming too small for its valley.

Elbow of Capture

The point of capture where a sharp bend and abrupt change of river flow direction occurs.

Wind Gap

The dry valley area located between the elbow of capture and the misfit stream where water has stopped flowing and dry deposited gravels are exposed.

River Rejuvenation

The process where an already well-developed river system regains energy and erosive power to actively erode vertically again, cutting a new valley inside an older one.

Knickpoint

A sharp break or step in the longitudinal profile of a river where the old base level meets the new base level of erosion, frequently forming a waterfall.

River Terraces

Step-like benches on valley sides representing former floodplains that were abandoned when renewed vertical erosion carved out new valley floors.

Valley in a Valley

A rejuvenation feature formed when renewed vertical downcutting carves a new, steeper valley into the floor of an older, broader valley.

Incised / Entrenched Meanders

The deep, steep-sided curves of a winding river that has eroded vertically into the landscape, with steep slopes on both sides rising to the former floodplain.

Remote Sensing

Collecting information about a feature on the Earth's surface without coming into physical contact with that feature.

Active Remote Sensing

Remote sensing systems that emit their own artificial radiation to illuminate the target, such as radar or the flash of a camera.

Passive Remote Sensing

Remote sensing systems that rely on naturally available radiation, such as reflected sunlight, to illuminate the target.

Spatial Resolution

The level of detail or clarity captured in spatial data, such as a satellite image or map, determined by pixel size.

Data Standardisation

Transforming and harmonizing geographic data to conform to a common set of rules, specifications, or conventions, which improves compatibility and integration.

Data Layering

A GIS process of placing thematic layers (such as land cover, elevation, and transportation) on top of one another to produce a composite map.

Data Security

The protection of the confidentiality, integrity, and availability of spatial data and the systems that manage it.

Data Integration

Combining geographic data from multiple sources and formats into a unified dataset for spatial analysis and decision-making.

Data Sharing

Making data available and accessible to organizations or individuals other than the original creator of that data.