1 HYDROSPHERE1 INTRODUCTION This unit has three components, The Hydrological cycle and its features. Working with hydrographs and Studying rivers.

2 HYDROSPHERE1 In the Standard Grade course, you learned about four parts of this cycle. At Higher, we need to know more detail. THE HYDROLOGICAL CYCLE EVAPORATION CONDENSATION PRECIPITATION ADVECTION INFILTRATION SURFACE RUN-OFF

3 HYDROSPHERE1 SURFACE RUN-OFF The process of water flowing over the surface- as in rivers- to return to the sea. ADVECTION Bringing in more water from another area, usually by wind-blown clouds. INFILTRATION The way that water sinks below the surface, usually into soil or rock layers underground.

4 THE WATER TABLE This is the surface of water that has sunk into the ground. Below this table, the rocks have their pores full of water. Above this level, air lies in the pore spaces. The water table rises and falls according to the amount of precipitation and evaporation in the area. Water table after a heat wave Water table after a period of rain surface SATURATED ROCK surface SATURATED ROCK

5 HYDROSPHERE1 There is the same amount of water in/on our planet as there was at the birth of our planet ! The water just goes round and round the system. DID YOU KNOW ?

6 HYDROSPHERE Look at the diagram on the next slide. It can be found in core higher pg 39. Take a copy of the diagram...

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8 HYDROSPHERE1 Above- interception diagram Below- overland flow in a field

9 Drainage Basins A drainage basin is an area of land drained by a river and its tributaries. A drainage basin is an area of land drained by a river and its tributaries. The boundary of a drainage basin is called a watershed. This is usually found on higher ground. The boundary of a drainage basin is called a watershed. This is usually found on higher ground. The drainage density of a drainage basin is important - The drainage density of a drainage basin is important - High drainage density on impermeable rocks and clays – greater flooding risk High drainage density on impermeable rocks and clays – greater flooding risk Low drainage density on permeable rocks and sand. Low drainage density on permeable rocks and sand. Unlike the closed system of the hydrological cycle, the drainage basin system is open. It has inputs, stores, flows and outputs. Unlike the closed system of the hydrological cycle, the drainage basin system is open. It has inputs, stores, flows and outputs.