Geography Revision Test 1

Glossary:

Agriculture: The farming of animals or crops

Arable Land: Land that can be used for growing crops

Deposition: The laying down of sediment that has been transported by wind, water or ice

Drainage Basin: An area of land where all surface water converges on a single point

Drought: A shortage of rain which adversely affects plant and animal life

Dryland Salinity: Loss of farm and grazing land due to rising salt levels

Erosion: The wearing away of the land or soil by wind or water

Fertile Soil: Rich in nutrients for growing crops

Groundwater: Water located in rock pores beneath the Earth’s surface

Horticulture: The farming of plants or flowers

Infiltration: The seepage of water into the soil

Irrigation: The adding of water to the land in order to water crops (sprinklers, diversion channels, pipes, ditches)

Land Degradation: Decline in quality of soil, water or vegetation conditions

Land Use: The intended purpose of an area

Marginal Land: An area with low, unreliable rainfall, poor soil or steep slopes which make the growing of crops risky

Resource: Anything that occurs naturally or is man-made which fulfils a need or want of people

Rural: Country regions where activities such as agriculture, horticulture, forestry, and mining dominate

Salinity: Level of saltiness

Sustainability: meeting the needs of the present while ensuring that we can meet the needs of the future

Topsoil: The uppermost level of soil which determines yields in agriculture

Transpiration: Water loss from plants through the stomata of their leaves, into the atmosphere

Urban: Large, permanent settlements such as cities or towns with little agricultural employment

Watertable: Upper level of the aquifer or groundwater layer

Wetland Salinity: Saltiness that results when overuse of water and irrigation causes rising watertables

Drainage Basins:

What is a drainage basin?
A drainage basin, or catchment, is an area of land that serves as a funnel to direct rainfall and excess water to a single point, where the waters flow into another water body such as a river. Adjacent drainage basins are separated by hills, mounds, ridges, or mountains. The term drainage basin refers to the whole area from watershed to watershed.



Diagram:



Catchment Area: Area from which rainfall flows into a river, lake or reservoir
Confluence: The point at which 2 rivers join
Floodplain: Low-lying land adjacent to a river, formed mainly by river sediments. It is subject to flooding.
Headwaters: The region where rain or melting snow originate to feed the rivers (often mountains)
Mouth: he point at which the river flows into a sea, ocean or lake
Source: The region where rain or melting snow originate to feed the rivers (often mountains)
Tributary: Any stream that flows into another stream
Watershed: The high point which separates adjacent drainage basins topographically




The Murray Darling Basin:

In the map above, the Murray Darling Basin is the brown area in South-east Australia. It is approximately one million square kilometres, and around 1/7 of the continent. It contains Australia’s two longest rivers; the Murray and the Darling, hence the name. It is bordered by the South Australian Coast, Lake Eyre, Bulloo-Bancannia, North-east Coast and South-East Coast drainage divisions.

Reasons for Land Degradation:

Processes are: Wind, water and salinity

1. Deforestation
The removal of trees for firewood, commercial logging or land clearing for farming or settlements

2. Overgrazing
Soil is exposed due to vegetation consumption by animals, meaning plants cannot regenerate

3. Compaction
Infiltration reduced by heavy machinery or hard-footed animals, making it difficult to use the land

4. Poor Land Management
Use of inappropriate farming methods for the type of land and/or soil

5. Acidification
Overuse of chemical fertilisers rather than natural fertilisers such as organic matter

6. Fires
Bush ad Scrub fires strip the soil of plant material

7. Pollution
Dumping of scrap metal, plastics, packaging and building rubble

8. Mining
Damages soil and underlying structure of the land

Remember this using CAMP FOLD (L as in land from poor land management)

Water Erosion

-Once the original plant cover has been removed, soil can be carried away by heavy rain and deposited elsewhere
-On sloping land, the excess water on the soil surface runs down the slope and carries away a thin layer of soil (SHEET EROSION)
-Water may flow in a series of small channels or grooves in the land. These are RILLS
-When rills become so large that they cannot be crossed by farm machinery, they are known as gullies. When left unattended, gullies can become many metres deep and many hundreds of metres long
-Results in instability of soil


Wind Erosion

-Wind can move soil thousands of kilometres
-Great deal of topsoil can be blown away
-Crops lost because they are blown out or covered in soil
-Soil structure can be affected (rills and gullies may form)
-Infrastructure damages with soil deposited over houses/ fences in heavy dust storms

Less than 1mm sediments = CREEP
0.1-1mm sediments = SALTATION (jumping)
0.001-0.1mm sediments = SUSPENSION

Salinity

Dryland salinity: Rising Salt (in non-irrigation areas)
Wetland salinity: Rising watertables (due to irrigation)

-Trees and deep-rooted plants removed due to European Settlement and later human needs, meaning there is nothing to control groundwater levels
-Irrigation causes rising groundwater
-Rising groundwater causes rising watertable
-Rising watertable brings dissolved salt closer to the surface, causing saline soil when within 2metres
-Crops unable to grow
-Infrastructure may be damaged
-Saltier groundwater and surface water


Geography Revision T1

Solutions:
1. Reforestation; the growing of more plants in order to improve and stabilise soil, meaning it will not be so easily washed away
2. Strip planting; Altering rows of regular crops with cover crops so that when there is heavy rain, cover crops will hold the soil in place
3. Avoid farming on steep slopes; this reduces the risk of water erosion, as the water will not flow downhill and thus the soil will not be carried away
4. Salinity-limit placed on amount of water that can be taken from the Murray
5. Saline water pumped away and watertables kept low
6. Water should be used more efficiently
7. Crop rotation, so that soil has time to regenerate
8. Reduce overgrazing, irrigation and deforestation
9. Limit destructive human activities
10. Switch to salt-tolerant crops