Rivers, Floods and Management: Drainage Basin Hydrological Cycle

Mind Map by , created over 5 years ago

A Levels Geography (Physical Geography-AS) Mind Map on Rivers, Floods and Management: Drainage Basin Hydrological Cycle, created by Andrew_Ellinas on 03/27/2014.

Created by Andrew_Ellinas over 5 years ago
Geography - AQA - GCSE - Physical - Rivers
Josh Anderson
Thar Desert- Hot desert LEDC Case Study
a a
Geography - Population
Grace Evans
Biology Unit 2 - DNA, meiosis, mitosis, cell cycle
Truman Doctrine, Marshall Plan, Cominform and Comecon
Alina A
The formation of Ox Bow Lakes due to meanders
a a
Lake Vyrnwy Case Study
a a
Uses of temperate deciduous woodlands, Epping Forest, Essex
a a
GCSE Geography - Plate Boundaries
Beth Coiley
Alps, Human uses of fold mountains case study
a a
Rivers, Floods and Management: Drainage Basin Hydrological Cycle
1 What is a Drainage Basin?
1.1 A drainage basin is the area of land that is drained by a river and its tributaries.
1.2 The drainage basin acts largely as a 'closed' system, because it has a very definitive outer edge or boundary called the watershed.
1.3 Key Words
1.3.1 Precipitation: The type, total amount and intensity are key factors in determining the nature of water movement.
1.3.2 Evapotranspiration: When water loss from the ground surface to the atmosphere (evaporation), combines with water loss from plants (transpiration) to form the main output from the system.
1.3.3 Interception: Vegetation, especially trees, intercepts some precipitation on its way to the ground. Water is then lost back into the atmosphere by evapotranspiration. intercepting plants also use the water for growth.
1.3.4 Depression Storage: When water is stored temporarily on the ground surface in the form of puddles
1.3.5 Soil Moisture: If soils is saturated, precipitation will flow as overland flow. Clay soils are wet and boggy (leading to overland flow). Sandy soils are much drier so have the opposite effect.
1.3.6 Baseflow, or Groundwater Flow: This is a very slow transfer of water through rocks.
1.3.7 River Channel: This is the river itself. Also forms the 'exit' for water transferred through the drainage basin
1.3.8 Percolation: This is the deeper transfer of water into permeable rocks - those with joints (pervious), or those that are porous.
1.3.9 Throughflow: Downhill transfer of water of water through the soil layer to the river.
1.3.10 Infiltration: Water moving from the ground surface into the soil.
1.3.11 Overland Flow: Rapid form of water transfer over the surface of the ground.
2 The Water Balance
2.1 In order to get a better understanding of water resources in a drainage basin, we use an equation called the water balance.
2.2 P = O + E +/- S
2.2.1 P = Precipitation
2.2.2 O = Total runoff (streamflow)
2.2.3 E = Evapotranspiration
2.2.4 S = Storage (in soil or rock)
2.3 An important aspect of the equation is the amount of runoff - expressed as a percentage of precipitation. It is a measure of the proportion of total precipitation that makes its way into streams and rivers