5 - deficit within the water cycle ✅

Question 1

what is a deficit in the water cycle

Answer 1

when there are greater outputs than inputs to the cycle resulting in a depletion of the stores

Question 2

what can cause deficits in the water cycle (3)

Answer 2

• seasonal variation eg dry seasons
• longer term climate change
• human depletion of stores for use

Question 3

what does more precipitation create

Answer 3

high precipitation = increased surface runoff and channel flow

so drier seasons = reduced river discharge and runoff

Question 4

what is a water balance graph

Answer 4

shows the balance between inputs and outputs

Question 5

how are wet seasons characterised (4)

Answer 5

• precipitation exceeds evapotranspiration = water surplus
• ground stores fill with water
• more surface runoff
• higher discharge = river levels rise

Question 6

how are dry seasons characterised (2)

Answer 6

• evapotranspiration exceeds precipitation = ground store depletion
• some flows into the river channel, isn’t replaced by precipitation

Question 7

what is the water balance co-efficient

Answer 7

difference between annual precipitation and potential evapotranspiration

Question 8

what is water stress

Answer 8

areas where total withdrawals from the area exceed the renewable inputs to the system so the stores begin to be depleted

Question 9

where is freshwater extracted from

Answer 9

• surface water stores eg lakes
• aquifers

Question 10

why do humans extract water

Answer 10

• household activities eg washing
• drinking water for exponentially growing population

Question 11

what is being done to save the Aral Sea

Answer 11

• more efficient irrigation system funded by UN and world bank
• dam that funnels water to Aral
• reducing salinity

Question 12

what are aquifers

Answer 12

AQUIFERS = permeable porous water bearing rocks such as chalk

Question 13

what are artesian aquifers

Answer 13

develop where sedimentary rocks have formed a syncline or basin like structure

the aquifer is confined between impermeable rock layers

Question 14

how did the Ogallala Aquifer form

Answer 14

• formed more than 2 million years ago from melting glaciers
• extensive groundwater resources were virtually unknown until the early 1900s and were not tapped for irrigation water until around 1950

Question 15

what are the key features of the Ogallala Aquifer (2)

Answer 15

• has extremely low natural recharge rate because its in an area with low precipitation
• water withdrawn from it is so big the aquifer is being depleted eight times faster than its natural recharge rate

Question 16

what problems can arise from water insecurity (5)

Answer 16

• drought
• waterborne diseases
• water pollution
• industrial decline
• potential conflict (water based conflict)

Question 17

what has been involved with abstraction of water (3)

Answer 17

• the Colorado has been heavily abstracted for water supply to desert cities such as Las Vegas and irrigation for farming regions such as the Yuma Valley
• sometimes it no longer reaches the sea
• caused conflict between land owners and indigenous Indian tribes

Question 18

what can resolve water conflicts in Colorado (3)

Answer 18

• talks have been held and quotas of river water that can be abstracted given to different interest groups
• native Indian groups have been given designated reservations where they have complete autonomy over the river
• however, there is no solution and the flow in the Colorado continues to decline

Question 19

how are aquifers recharged naturally and artificially

Answer 19

NATURAL - occurs naturally through the water cycle, can take thousands of years

ARTIFICIALLY- by humans through placing water back into the aquifer through various methods.
this is needed when extraction takes place more than natural recharge (system theory) and aquifer becomes depleted