Atmosphere 0.002% Ocean 97.2% Ice caps & glaciers 2% biosphere Rivers, lakes 0.6% Underground- lithosphere I P Et S E+C

Amount of interception hot and wet climate + Dense vegetation coverage + Types of vegetation: trees rather than grass, wide canopy, rough stem surface, large leaf surface etc +

infiltration Wet climate : more water for infiltration + Porous/ pervious/ permeable rock + Large / coarse grained soil + Gentle gradient + Small amount of vegetation / interception +

evapotranspiration Hot and wet climate increase the rate of evaporation and amount of vegetation + Dense vegetation + Mature trees > scrubs + Nature of surface e.g. ocean, vegetated surface +

Main stream tributaries Watershed/ water divide follows the crests of hills, ridges, spurs in the surrounding

River is moving water within a definite channel. A channel is a trough like depression at the bottom of the valley The river may be of permanent flow. The river may be of temporary flow.

Amount of water in channel increases Geology of the area: impervious / impermeable + Source of river is a permanent one; there is the melting of ice in spring; river capture + Human activities : clearing vegetation; oversteepening of slope, building of reservoirs etc + Steep gradient & the water stays short time on ground, less percolation is found. + Seasonal variation /changes of rainfall e.g. rainy season + Less vegetation cover in the area + Hot and wet climate +

River drainage system can be seen as an open system in which there is the flow of energy and matter into and out of the system or there is the exchange of energy and matter between the river system with the outside world. River drainage system is composed of different parts e.g. inputs processes outputs

Inputs : a) Liquid form : Rain water Melt water Spring water Waste water b) Energy form : Solar energy Heat energy c) Solid form : Eroded rock fragment from upper course of river Weathered materials Mass wasting materials from nearby slopes Minerals dissolved from the surrounding Waste material

Inputs get into the river system through different processes Liquid form Through the process of precipitation, throughflow, base flow Energy form Radiation Solid form River erosion from the upper course Weathering and mass movement Direct dumping dissolving Direct dumping

In the river system the work of river includes : 1. erosion 2. transportation 3. deposition

The river connects itself with the outside world through different outputs : 1. Gaseous / vapour form to the atmosphere 2. Liquid infiltrates into the bedrock and minerals dissolved and flow into the sea; divertion by man for irrigation, industrial and domestic use, absorption by plants 3. Solid soil is deposited at the lower course, river mouth

The outputs of river are sent out through different processes : 1. evaporation 2. Infiltration 3. Overland flow 4. deposition 5. evapotranspiration

There are two types of runoff/ overland flow : 1. Sheet flow 2. Channel flow in which water concentrates in a distinct depression.

Sources of river : a) Rainfall from the sky esp. in the humid equatorial region e.g. Congo River b) Melting snow in high latitude or high altitude areas e.g. River Rhone c) Spring fed river e.g. River Thames d) Water from lakes e.g. River Nile