Rivers GCSE AQA GEOGRAPHY ALREADY PASSED

Rivers GCSE AQA GEOGRAPHY ALREADY PASSED Abrasion rocks carried along by the river scratch away the river bed and banks. Attrition erosion caused when rocks transported by waves bang into each other and break up into smaller and rounder pieces. (Channel) straightening removing meanders from a river to make the river straighter. Cross profile the side-to-side cross-section of a river channel and/or valley. Dams and reservoirs a barrier (made of earth, concrete or stone) built across a valley to interrupt river flow. they store water and generate hydroelectric power , but are very expensive Discharge the quantity of water that passes a given point on a stream or river-bank within a given period of time. Embankments Raised banks constructed along the river. Hence the river can hold more water, protecting the buildings on a flood plain. Estuary the tidal mouth of a river where it meets the sea. Flood occurs when river discharge exceeds river channel capacity. Flood plain the relatively flat area forming the valley floor on either side of a river channel. Flood relief channels building new artificial channels, which are used when a river is close to maximum discharge. Flood risk the predicted frequency of floods in an area. Flood warning providing reliable advance information about possible flooding. Damage to possessions is less. Fluvial processes processes relating to erosion, transport and deposition by a river. Gorge a narrow, steep sided valley, often formed as a waterfall retreats upstream. Greenfield site a plot of land, often in a rural or on the edge of an urban area, which has not yet been subject to any building development. Hydraulic action the force of the river against the banks can cause air to be trapped in cracks and crevices. Hydrograph a graph that shows the discharge of a river, related to rainfall, over a period of time. Interlocking spurs A series of ridges projecting out on alternate sides of a valley and around which a river winds its course. Lateral erosion It widens the valley and the channel , it is dominant in the middle and lower course of the river. Levée Where natural embankments form during floods on the side of the river. (becasue the flow of water is slower) Long profile the gradient of a river, from its source to its mouth. Meander a pronounced bend in a river. Ox-bow