Short Response Geography

Front 1

Valley/river formation

Back 1

Valleys and rivers are shaped from three main processes occurring within a catchment; erosion; transportation and deposition. Erosion is the gradual removal of alluvium from the river banks and beds and occurs in 4 ways; corrasion, attrition, saltation and hydraulic action. Transportation is the term used to refer to the transportation of alluvium load through suspension, traction, solution and saltation. Deposition refers to the deposition of alluvium due to a decreased speed or volume of water, causing features such as deltas. These processes shape river systems, causing features such as meanders. A meander is a curve in a river created when soil & sediments are eroded from the outer banks of river and transported up the river, being deposited on the inner back further along the river. Transportation of sediment causes undercutting to occur with the high water velocity. This feature often occurs in the valley and lower tracts.

Front 2

Dams (part 1)

Back 2

Construction of dams can have many environmental, social and economic impacts an area, both positive and negative. These impacts can be seen to varying degrees in different locations throughout the world, such as the Three Gorges Dam in China and the Hinze Dam in the Numinbah Valley, Australia. Positive effects that can be observed from the construction of the Three Gorges Dam include 'clean' hydropower that is able to supply power to 30% of China, causing a significant reduction in CO2 and sulphur emissions, flood mitigation to save lives during monsoonal seasons, an internal shipping facility allows for increased trade and a model of engineering progress in the 21st century.

Front 3

Dams (part 2)

Back 3

On the other hand, disadvantages include destruction of magnificent landforms, loss of ecology - such as the Pink Dolphin, as many as 1.3 people relocated without compensation, silt trapping - creating the need for constant dredging, economic cost of building the dam, pollution build up as a result of slowed tributaries and loss of cultural artefacts. Similar effects are present in the Nerang Catchment with the building of Hinze Dam. However, these effects are significantly less, due to the decreased size of the reservoir.

Front 4

Dams (part 3)

Back 4

One of the most prevalent issues in the Nerang Catchment is the decreased water flow downstream of Hinze Dam. Overall, building dams is extremely effective for the collection of water for human use. However, the environmental, social and economic disadvantages are extremely prevalent, especially on a large scale, such as the Three Gorges Dam and therefore the development of less destructive water collection strategies would be beneficial for the communities and ecosystems involved.