human impacts on the hydrological cycle

Question 1

list the human impacts on the hydrological cycle

Answer 1

1) deforestation
2) agriculture
3) urban development
4) GCC

Question 2

outline how deforestation impacts the hydrological cycle

Answer 2

1) vegetation intercepts rainfall which may evaporate before reaching the floor
2) trees return a lot of water to atmosphere via evapotranspiration
3) loss of trees would cause decreased precipitation, increased surface run off and increased soil moisture

Question 3

outline how agriculture affects the hydrological cycle

Answer 3

1) soils is compacted by livestock or heavy machinery preventing infiltration and increasing surface run off
2) irrigation increases evaporation rates
3) loss of soil biota reduces infiltration increases surface run off

Question 4

outline how urban development affects the hydrological cycle

Answer 4

1) creation of impermeable surfaces which reduces infiltration while increasing surface run off increasing flooding down stream

Question 5

outline how GCC affects the hydrological cycle

Answer 5

1) increased temps mean increase evaporation increasing precipitations
2) more rapid melting of ice and snow

Question 6

what are the environmental impacts of reservoirs

Answer 6

1) wildlife barrier - prevents recolonization of areas and migratory breeding fish such as salmon
2) habitat change - flooding an area will destroy previous habitats
3) change in river flow- changes to erosion and sedimentation, changes in nutrients
4) sedimentation - will settle at resavoir not travel downstream decreasing building or river banks
5) microclimates- reduce temp fluctuations so warmer in winter and cooler in the summer, water provides less friction so higher wind speed, increased evaporation

Question 7

what are the features of an aquifer

Answer 7

1) permeability - the measure of ease with which fluids may flow through a rock
2) porosity - the measure of the proportion of rock that could hold water
3) surrounding geological features - permeable top to allow infiltration, impermeable bottom

Question 8

what is aquifer recharge

Answer 8

the natural inflow of water into an aquifer which is in a state of dynamic equilibrium with the outflow usually takes place as precipitation landing on ground surface infiltrates and peculates through the ground

Question 9

what are some effects of over-exploited aquifers

Answer 9

1) ecological impacts
2) salt water incursion
3) subsidence
4) reduced supplies

Question 10

outline the ecological impacts of over exploited aquifers

Answer 10

if the water table is lowered then plants with a higher water requirement will die as they fail to compete with plants with lower requirements for water

if wetlands dry out it will cause aquatic organisms to die

Question 11

outline salt water incursion as a result of over exploited aquifers

Answer 11

if the water table falls below sea level then seawater from the sea will flow sideways into the aquifer to replace freshwater this makes the aquifer unstable for irrigation

Question 12

outline subsidence as a result of over exploited aquifers

Answer 12

water that is no longer present in the spaces of the rock cant provide support for compacted material above causing collapse

Question 13

how is aquifer depletion monitored

Answer 13

1) boreholes to check water table levels
2) GRACE satellites = their orbit is affected by the force fo gravity which is influenced by the mass of water in aquifers below their flight