ESS Topic 4.1

Water systems

Major stores in hydrological cycle

30.1% groundwater

0.42% surface & atmospheric water

68.7& glaciers and ice caps

Earths water breakdown

saltwater : 96.5%

freshwater:2.5%

• 30.1% ground water

• 68.6% glaciers & ice caps

• 1.3% surface water

  • 73.1% ice and snow

  • 20.1% lakes

  • 3.52 soil moisture

  • 2.53 swamps and marshes

How does deforestation affect the water cycle

1. deforestation would remove forest hydrological advatages such as

   • forests protect the soil by intercepting raindrops —> reduce erosion

   • forests stop the movement of water and allow for infiltration —. slows errosino

   • forests absorb water by the root system —> reduces the flow of water

a loss in forests could cause …

• removal of trees as water stores

• fun-off would flow ore quickly —> increases soil errosion

• larger amounts of water entering watershed —> downstream flooding

• higher sediment in rivers —> lowers water quality and higher chances of flooding

How does urbanization affect teh water cycle?

-reduces the amount of water in ground w by reducing run-off or polluting run-off

sustainable urbanization strategies :

• reducing the quantity of polluted run-offs by encouraging water to move through ground and aquifers —> slows soil erosion and flooding

• slowing the velocity of run offs —> reduces the surface discharge and protects clean water from polluted water

Affects fo agricluture ofn the wate cycle

• encourages excessive abstraction of water —> diminishes the source of water

  • abstraction rates are not sustainable is rate of extraction exceeds rate of replenishment

• excessive irrigation —> increases soil salinity

• run-off from phosphates and fertilizers —> contaminate run-offs and affect marine species

• animal waste —> pollute run-offs and waterways / ground water

water usage. in agriculture can be reduced by :

• using crops that require less water

• drip irrigation

• increase soil moisture and reduce erosion (bunds, terracing, contour ploughing and cover crops)

Strategies to reduce agricultural water pollution:

• avoid fertilizers, pesticides, manure near waterways or ground groundwater abstraction points or close to rainwater points

• match use of nitrogen fertilizers to uptake of crops

• collect / manage animal waste

• Integrated pest control - uses natural pest predators

• change farming techniques (crop rotation )