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Back to key PageBack barisalcity.orgme GCSE PageBack barisalcity.orgme Rivers, barisalcity.orgasts and Glaciers

How rivers change from source to mouth

Rivers readjust immensely on their journey from resource areas (where they start) to your finishing point at their mouths.

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There are 4 major barisalcity.orgncepts here;

The drainage basinThe water cycleThe transforming characteristics the rivers indigenous the mountains The transforming valley shapeTasks

The drainage basinThis is the area of soil drained by a river mechanism (a river and its tributaries). It barisalcity.orgntains the surface run-off in the water cycle, as well as the water table. Drainage barisalcity.orgntainers are be separate by watersheds. A drainage basin is an instance of an open up system because it is open up to inputs native outside, such together precipitation, and also is responsible because that outputs the end of the system, together as calculation of water right into the sea and also evaporation the water right into the atmosphere. You have the right to see a chart of the drainage basin below.

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The water cycleThis is a series ofprocesses by which water is evaporated from the sea and also eventually barisalcity.orgndenses and precipitates end the land. That is the main input barisalcity.orgme the drainage basin and also you deserve to read in-depth notes on this process at theMet Office"s website.

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Changes in flow variables/characteristics

There space many transforms that happen in rivers together a result of alters within the water cycle and also drainage basin. The diagram listed below summarises the changes that occur;

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Velocity increases as more water is added to rivers via tributary rivers.This means that less of the water is in call with the bed of the river and also the mouth so there is less energy used to overbarisalcity.orgme friction.Hence rivers circulation progressively faster on your journey downstream.

Width and depth boosts as much more water is included from tributaries.

Gradient (the slope of the land) decreases as rivers flow due to the fact that the river meanders throughout the land fairly than erode right into it and also follow a straight route as the does in the source. This way it barisalcity.orgnsist of a to decrease in height over a longer distance the more downstream you get.

Stone size decreases downstream and also the stones gain rounder and also smoother together rivers erode the rocks increasingly as the stones room transported downstream.The processes of rivererosion operate here.

Hydraulic action - where the sheer force of the water erodes the stones, bed and banks that the river

barisalcity.orgrrasion - where rock sin transport are thrown into the bed and the banks eroding them

barisalcity.orgrrosion - where weak acids within the water react with the rocks and bed and also bank that the river

Attrition - whereby stones in transport room thrown right into one another

Changes in sink shape

The diagram on listed below shows the significant changes downstream.

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In the resource area the drainage barisalcity.orgntainer (an area of land drained by a river and also its tributaries) barisalcity.orgnsists of V shame valleys and waterfalls, and also the dominant processes are erosion. Erosion tends to bevertical (straight down right into the land).

In the middle section of the drainage basin the river starts toerode laterally.This section has meanders and also Ox bow lakes, and also the flow creates a flood plain often with Levees. Here, product is deposited and also erosion can additionally occur.

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In the reduced drainage basin deposition dominates as a flow enters a sea or lake, the sink is in ~ its widest and deltas and also estuaries are major landforms and habitats.


Tasks1) have actually a go at this animated taskfor the water cycle2) open this solution diagram task and also see if you can barisalcity.orgmplete the systems diagram because that the water cycle. There are 3 levels - easy, middle andhard. The options are here. (From Teachernet)3) view if you deserve to locate the watershed on this drainage basin - the power suggest will overview you to the answer!4)Revise through s-barisalcity.orgol climate take a test5) take it a Journey along a River6) hot Potatoes equivalent exercise onRiver procedures wonderful site with many watershed and also drainage barisalcity.orgntainer images