- Join over 1.2 million students every month
- Accelerate your learning by 29%
- Unlimited access from just £6.99 per month
AS and A Level: Hydrology & Fluvial Geomorphology
Meet our team of inspirational teachers
Five things you need to understand about hydrology and fluvial geomorphology
- 1 Make sure you understand the concept of systems, and the difference between a closed system (the global hydrological cycle) and an open system (the drainage basin)
- 2 Learn the correct definitions of all the specialist terms (eg percolation, throughflow, hydraulic radius, etc.
- 3 Learn a case study which shows how the theory relates to an actual example of a real river basin.
- 4 Remember that rivers are not static – they are affected in the short term by weather patterns and human activity and in the long term by changes in climate, tectonic processes and sea levels.
- 5 Pay attention to scale: for example British rivers (and British floods) are tiny compared to the great rivers (and great floods) experienced in other parts of the world.
Common errors in hydrology and fluvial geomorphology essays
- 1 Although rivers near their source often look like they are flowing quickly, and rivers near their mouth look like they are flowing slowly, river velocity increases downstream. This is because there is more turbulence upstream (due to friction) and rivers flow more efficiently as they get further downstream (as friction reduces).
- 2 Infiltration is the movement of water into the soil. Percolation is the movement of water into the underlying rock. Students often confuse these two terms.
- 3 Landforms are often referred to as landforms of erosion (eg waterfalls) or landforms of deposition (eg deltas). However, it is important to remember that other processes (erosion, weathering, transportation, deposition, mass movement) also contribute to the formation of these features.
- 4 River valleys and river channels are not the same thing.
- 5 Remember that flooding can bring benefits as well as costs.
Top facts to use in your essay answers
- 1 Water covers approximately 71% of the Earth's surface
- 2 96.5% of the planet's water is found in oceans, 1.7% in groundwater, 1.7% in glaciers and the ice caps of Antarctica and Greenland, a small fraction in other large water bodies, and 0.001% in the air.
- 3 Only 2.5% of the Earth's water is freshwater, and 98.8% of that water is in ice and groundwater. Less than 0.3% of all freshwater is in rivers, lakes, and the atmosphere.
- 4 The Amazon river is by far the largest in the world in terms of discharge (which is greater than the next seven largest rivers combined), and it has the world’s largest drainage basin. The Nile is generally recognised as the world’s longest river (approximately 6550 km).
- 5 River flooding has been the cause of some of the world’s worst environmental disasters. For example, the 1931 Yangtze floods in China may have killed up to 4 million people.
due to the increase in (or constant supply of) debris and weathered rock. However, though debris is required at the base of the glacier so that erosion can occur, if there is too much debris then the speed of movement will be reduced by the 'load' and with it the rate of erosion will fall also. This is also true with the amounts of water at the base of the glacier; 'Just a few millimetres of water at the base of a glacier to in crease the speed of the glacier by 40% to 60%' (Weertman).
- Word count: 881
At the start of the course of the river, the valley formed is in a "V" shape, due to the vertical erosion at the steep gradient; also weathering and soil creep of the surrounding land. Another reason that the banks and bed of the river get eroded is because of the increase in discharge. As the river continues along it's course, tributaries will join the river, and the river has a sudden increase in discharge at the confluence. This means the riverbank has to become wider to allow for the extra water.
- Word count: 1397
* Areas - Bihar and west Bengal * Speciality - First in India. coal and iron-ore deposits. * Indira Gandhi Canal Project- * River - Ravi and Beas * Canal length - 468 Km(main canal) * Storage -690000 hectare metres * Areas -Rajasthan, and north western part of India * Kosi Project- * River - Kosi * Irrigation - 873000 hectare meters * Areas - Bihar and Nepal * Speciality -India's cooperation with Nepal * Hirakund- * River - Mahanadi * Storage - 8100 million m3 * Power - 270 mw * Speciality - the longest dam in the world with the length of 4.8 Km.
- Word count: 1227
I learnt that at the source of the stream the river's energy is focussed downwards which creates vertical erosion. This type of erosion causes the channel to become deep and narrow. Further drownstream, due to the formation of meanders, the rivers energy is focussed outwards in the form of lateral erosion. This occurs on the outside of the bends. At different stages of a river there are various processes which produce different landforms For example, v-shaped valleys in highland regions and deltas in lowland regions.
- Word count: 561
From this confluence the main trunk of the Amazon flows in a generally eastern direction to the Atlantic Ocean. The Amazon enters the Atlantic through a broad estuary, roughly estimated at 240 km (about 150 miles) in width. Here delta deposits have formed a maze of islands that separate the river into branches. The mouth of the main stream is 80 km (50 mi) wide. This branch, known as the Par�, is separated from a smaller branch by Maraj� Island, which has an area of more than 36,000sq.km.
- Word count: 1667
Describe and explain how the processes operating in permafrost result in landforms specific to periglacial areas.
Further expansion by the ice widens the capillaries in the soil, allowing more moisture to rise and freeze. The crystals, or the larger ice lenses which form at a greater depth, force the stones above them to rise until eventually they reach the surface. Patterned ground is a general term used to describe the stone circles, polygons and stripes found in soils subjected to intense frost action. On steeper slopes, stone stripes replace stone circles and polygons. During the severe winter cold the refreezing of the active layer causes the soil to contract.
- Word count: 996
One of the important reasons Greg chose the site is because of the transport links. The bridge water canal would provide easy shipping of cotton near to the mill, then the last few miles would have to be done by horse and cart. Manchester is close to Styal, this is good because Manchester was one of the biggest industrial cities and this would provide Greg with workers and raw materials. Liverpool is relatively close to Styal. Geographical factors also played a part in the choosing of the Styal location because on that land the river Bolin flowed through.
- Word count: 526
Biology SC1 - An Investigation Into The Effect Of Pollution On The Distribution Of Organisms Along The River Roding System
We did this at the site and so had taken our equipment to the site. Firstly nitrates were tested for. A member of the group removed the nitrate stick from the container and dipped the end with the two pads in the river for 1 second. We waited 1 minute. The colour on the pad was compared with the colour chart to see the nitrate level. The nitrate level was recorded. Then a phosphate test was carried out. Firstly 5ml of the water from the river was placed in a container. There were two reagents.
- Word count: 2847
There are 230 river and tributaries in Bangladesh in total, which all drain southwards. The quality of life in Bangladesh is low, as both the population density and the death rate are high, and both Life expectancy and adult literacy are low. The land in the Delta (towards the Bay of Bengal) is vastly used for arable crops, as it is so fertile and flat. Most people in Bangladesh earn their living through farming, so they have to grow lots of food.
- Word count: 493
To find out how channel characteristics such as width, depth, area, efficiency, gradient and bedload change downstream
It causes the river dimensions to become wider and deeper, or in the case of river material, smaller and rounder Erosion occurs through four processes: * Abrasion- A sand paper effect, where materials rub along the bed and banks of the river causing them to erode. This process is more effective during times of flood and is the major method by which the river erodes both vertically and horizontally. * Corrosion/ solution- A chemical reaction that happens between rock and the water e.g.
- Word count: 3460
The removal of vegetation means that interception cannot take place. Interception helps with flood control as it slows down water reaching the river and so entering the water cycle. This reduces flooding because there is not a sudden and uncontrollable increase in discharge levels, instead the discharge will increases slowly and steadily which will mean that the river can allow other water to flow into seas and lakes before having to contain more water. On a storm hydrograph this could be seen because the rising discharge limb would not be very steep, the lag time would be much greater and therefore the peak discharge would not be as high, see Figure 1.
- Word count: 1830
This is part of the normal climate variation cycle. As said before, glaciers begin to form when snow remains in the same area for long periods of time, where enough snow accumulates to transform into ice. Each year, new layers of snow cover and compress the previous layers. This compression makes the snow to re-crystallize. Slowly, the grains grow larger and the air pockets between the grains get smaller, causing the snow to slowly compact and increase density. After two winters, the snow turns into "firn" (firn is the middle state between snow and glacier ice).
- Word count: 1086
Consequently, cold based glaciers don?t erode a lot. A glacier is a system which has inputs, outputs and stores. The main input of a glacier is obviously snow, either from precipitation or avalanches. First, the snow settles. It has a loose, fluffy consistency at this point. Over time, as more snow falls, the increased weight on top turns the fresh snow into a denser, more granulated kind of snow called firn or neve. Air is squeezed out, and particles of ice are compressed together by the continuing accumulation of snow and ice. Water also melts (meltwater) and refreezes in the air spaces, making the ice more dense, forming a glacier. The rate of formation varies with area and temperature.
- Word count: 1465
To what extent should cold environments to be considered as fragile? How far does this affect their development?
The slow rate if of plant growth means that any disruption takes 50 years to correct. There is also low productivity because Bacterial activity is low due to cold temperatures and waterlogged conditions, stopping the recycling of nutrients and decomposition. Drainage is poor due to frozen ground, especially in permafrost zones. Although active layer thaws in summer, sub soil remains frozen. Soil contains angular fragments as a result of freeze thaw and frost heave.
- Word count: 403
A good example was the 1998 flood that killed over 1500 people. The floods that hit the UK in 2007 for instance were caused by higher than average rainfall where in some places a months rainfall fell in a 24 hour period. There are four main ways to manage floods. The first being a structural approach ? through the use of engineering. This is most commonly used in places of high wealth or MEDC?s because of its high cost. The second is river basin management or reducing the impact of high river levels by managing land use.
- Word count: 1194