1.1 The worlds water supply is contained in a closed system called the hydrological cycle Flashcards
River environments
What is the hydrological cycle?
The hydrological cycle is a giant closed system of the global circulation of water .
What is a closed system?
A closed system refers to there being a fixed amount of water as water never leaves or enters the earth
Draw a diagram of the hydrological cycle:
Refer to text book page 1
Name the stores in the hydrological cycle:
- The atmosphere
- The land - Stored in rivers, lakes and resevoirs water also taken in by plants and also stored below ground in soil or bedrock as groundwater store. Also can be stored as snow or ice or glaciers
- The sea 95% of water stored in sea
Name the flows in the hydrological cycle and describe them:
- Evaporation - Heat of sun causes water to change into gas
- Transpiration - Plants breathe out water as water vapour
- Condensation - Water vapor cools to form water droplets (clouds)
- Precipitation - Rain, hail or snow from atm - land
- Over land flow - (surface runoff)
- Infiltration and percolation - Water moving into soil and if very deep soaked into rocks called percolation. Moves downwards
- Throughflow - Takes place between ground surface and top of ground water store, moves through soil
- Groundwater flow - Underground transfer of water to rivers deep below rock
What is a drainage basin?
A drainage basin is where water collect and drains of into a river. It is an open system as the amount of water varies and has external inputs and outputs. Like a mini hydrological cycle.
Define watershed:
It is an imaginary line drawn around a rivers water
Draw a diagram of a drainage basin:
Refer to text book page 1
List the inputs of a drainage basin:
- Energy from sun
- Precipitation/moisture from other basins
- Water from tributary basins
List the outputs of a drainage basin:
- River discharge
- Water lost by evaporation and transpiration
Define source:
Start of a river, furthest point from mouth/estuary
Define channel network:
The system of surface and underground channels that collect and transport precipitation
Define mouth/estuary:
The end point of a river where river meets sea
Define tributaries:
Small streams of water entering the main channel
Define confluence:
Where two rivers meet or tributaries meet with main river
Define river regime:
Amount of discharge of a river at a specific point over the whole year
Define hydrograph:
Amount of discharge over time at a specific point measure in cm3/s represented on a graph
Define discharge:
Amount of water carried by a rive r at any specific time and specific point
Why is it important to know how quickly rain will reach drainage network?
It is important to know this as rain may reach quickly and the channel may not be able to cope resulting in a flood
Define storm hydrograph:
Records changing discharge after a passing storm represented on a graph
Define lag time:
Delay between peak rainfall and peak discharge, the shorter the quicker water reaches river
Define storm flow:
Additional discharge related to passing of rainstorm
List factors affecting river regimes and how they affect it:
- Rain intensity - heavy rain doesn’t sink quick enough, overland flow
- Temperature - Affect form of precipitation, eg snow takes time to melt and if ground frozen overland flow
- Land use - Tree intercept and delay reaching ground, bare soil rock will speed surface runoff and concrete
- Steep slopes - Cause rapid surface runoff, water reaches quicker. Flat and gently sloping may lead to water sinking
- Rock types - Permeable rock may delay water as they allow infiltration and percolation
- Dams and reservoirs - Regulate discharge
