Hydrological Cycle

impact of agriculture

• irrigation artificially supplies water

  • artificially high evapotranspiration rates → higher atmospheric moisture

  • increased surface run off

  • increases in precipitation downwind

• deforestation reduces interception → more flooding/surface run-off

impact of deforestation

• forests absorb rainfall & facilitate infiltration

• deforestation:

  • increases surface run-off

  • reduces evapotranspiration → reduced atmospheric moisture

  • increased erosion

  • saturated soil → flooding

impact of urbanisation

• impermeable surfaces

  • prevent infiltration → reduced groundwater recharge

  • increased flooding

• drainage systems overload natural water stores → downstream flooding

• higher temperatures (UHIE) → increased evaporation

impacts of industry

• use of water in mining

  • to takee PM from the air, reducing risk of respiratory disease

• pollution of water sources

  • Bangladesh; heavy metal leaching

• over abstraction from local sources

definition of precipiation

process of water falling from the atmosphere to the Earth's surface in the form of rain, snow, sleet, or hail

defintion of advection

horizontal movement of water vapour, clouds, or precipitation caused by the prevailing wind patterns

definition of evaporation

process by which liquid water changes into a gaseous state (water vapour) and enters the atmosphere from water bodies such as oceans, lakes, and rivers

definition of transpiration

process by which plants absorb water from the soil through their roots and release it as water vapour through pores called stomata in their leaves

definition of evapotranspiration

combined process of water vaporisation from the Earth's surface (evaporation) and the release of water vapour by plants through transpiration

definition of sublimation

direct transition of water from a solid (ice or snow) to a vapour state without melting first

definition of condensation

process in which water vapour in the atmosphere transforms into liquid water, forming clouds or dew, as a result of cooling

definition of melting

process by which solid ice or snow changes into liquid water due to an increase in temperature

definition of freezing

process by which liquid water changes into a solid state (ice or snow) due to a decrease in temperature

definition of flooding

overflow of water onto normally dry land, often caused by heavy rainfall, melting snow, or dam failure

definition of surface run off

movement of water over the Earth's surface, typically occurring when the ground is saturated or impermeable, leading to excess water

definition of infiltration

process of water seeping into the soil from the surface, entering the soil layers and becoming groundwater

definition of percolation

downward movement of water through the soil and underlying rock layers, eventually reaches aquifers or groundwater reservoirs

definition of stream flow/currents

movement of water in streams, rivers, or other water bodies, driven by gravity and the slope of the land, ultimately leads to oceans or lakes