Explain what it is meant by, in a drainage basin, by the terms drainage density and stream order
A) Explain what it is meant by, in a drainage basin, by the terms drainage density and stream order. The drainage basin is an area of land drained by a river and its tributaries. Drainage Density represents an approach to the quantitative analysis of drainage basin. It is the average length of channel per unit area of the drainage basin. It is calculated as shown below. Drainage density is a qualitative analysis of the areal properties of a river basin . Drainage density is useful as a measure of frequency and spacing of streams within the drainage basin. It also helps to determine the texture of dissection of a drainage basin- the extent to which the landscape is cut into by river valleys and in turn influence slope development. Generally, there are 4 categories of drainage density and corresponding texture of dissection. Very low- less than 8km/km sq coarse Medium low- 8-20 medium High density- 20- 200 fine Very high density- more than 200 ultra fines Drainage density and texture of dissection varies in response to these factors: * Permeability of surface- a highly permeable material such as sand tends to give low drainage density because of high infiltration capacity and little water is available as surface runoff to maintain channels. * Rock type * Topography * Vegetation- dense vegetation helps to intercept rainfall, because of infiltration capacity and
Flooding, one of the most disastrous natural hazards.
Geog Summer Assignment- Essay Question 2 Stella Kwok (7) Flooding is one of the most disastrous natural hazards. Take Huang He Basin in China as example, originally, intense rainfall in summer is one of the main causes of flood. With rapid urbanization and population growth, the built environment and the socio-economic characteristics is getting more important in contributing to flood hazards. To minimize the impact of flooding, take Huang He Basin in China as example, some preventive measures, such as flood control projects, are carried out. Flooding refers to the inundation by water of any land area not normally covered with water owing to a relatively rapid change of the water level. It often happens in the lower course of Huang He Basin. Firstly, physical environment is one of the main factors leading to flooding. Meteorologically, snowmelt in the upper course in spring causes sudden increase in discharge and blocking of ice-floes in river channels. In summer, the rainfall is concentrated in July and August, being highly variable. Prolonged and abnormally high rainfall may also increase the discharge of lower course of Huang He, allowing the floodwater to overflow its banks. The climatic condition throughout the year leads to the occurrence of flood. Topographically, there is a sudden decrease in gradient at Kaifeng, between the Loess Plateau and the
Explain where and why depositional landforms occur along the course of a river.
Explain where and why depositional landforms occur along the course of a river. Rivers have three courses. The course is the journey the river makes to reach the sea. Rivers never have a straight course from source to mouth. Their course is always irregular. Along this course depositional landforms can occur. Landforms can be formed from the deposition of weathered and eroded surface materials. On occasion, these deposits can be compressed, altered by pressure, heat and chemical processes to become sedimentary rocks. This includes landforms with some of the following geomorphic features: beaches, deltas, floodplains, and glacial moraines. The upper course is found in the mountains and hills where the river rises from its source and often waterfalls and rapids are also found in this course. The river is usually fast flowing in the upper course; also there are lots of stones and boulders for the water to flow over. Furthermore, the river starts as a stream in the upper course and flows through valleys. The middle course, however, is where the river starts to become wider and deeper. The land, which the river flows over, is becoming flatter and this is where the river starts to meander or bend in the middle course. The lower course is where the river becomes its widest and deepest. This course is found closest to the sea where the river has its mouth. The flat area of land by
To see how a river and its characteristics change with increasing distance downstream.
AIM To see how a river and its characteristics change with increasing distance downstream. OBJECTIVES . To see how mans influence effects the river. 2. To see if width, depth, velocity, bedload size, biological content and chemical content change downstream. HYPOTHESIS . Width should increase with increasing distance downstream. 2. Velocity should increase with increasing distance downstream. 3. Depth should increase with increasing distance downstream. THEORY An ideal river THE UPPER COURSE- In the upper course, the river is above its base level. This gives the river a lot of potential energy. The river is trying to cut down to its base level so mainly erodes in a downward direction. This helps to create the v-shaped river valleys in upland areas. THE MIDDLE COURSE- As the river flows downstream the gradient becomes less steep. Lateral erosion becomes more important than vertical erosion and the river starts to meander. Some of the rivers energy is also used to transport eroded material downstream. THE LOWER COURSE- The river is now nearing its mouth and deposition becomes the most mportant process encouraged by the large load carried by the river, any obstruction, any fall in the volume or any loss of velocity. The table below shows different features at the upper middle and lower courses of a river Upper course Middle course Lower course River
Rivers Survey.
Rivers Survey Introduction On Monday 28th of September we ventured to Dunston Beck. We went to Dunston Beck in order to conduct a river study. The undertaking of a river study was for Geography Coursework that would contribute to our final GCSE mark. Dunston Beck was not chosen on the spur of the moment but for a variety of reasons. The main reason in fact was that Dunston is a relatively local village to Sleaford. Dunston is just over half way between Sleaford and Lincoln. Due to Dunston being local this gave us plenty of time to conduct our river study. Also the source of Dunston Beck is positioned right on the Lincoln Edge. A Simple Map of Lincoln Edge and The Geology of Lincolnshire. Dunston Beck was also chosen because of its array of river features. Observable Features. These include: River cliffs Meanders Slip Off Slopes Slumping Juncas Grass Vegetation Springs Ox Bow Lakes Tributary Old River Channel Braiding It was easy to see why Dunston Beck was chosen as it embraced all those features listed above situated in the same place. It gave us a chance to test a vast array of hypothesis in the same day. To better Dunston Beck would be extremely hard. The location of Dunston Beck can be seen clearly on the following maps. Aims Of Study. The aim of our study was to create and test numerous hypotheses. When we had reached Dunston
Investigate how the river Breamish's characteristics change from source to mouth.
Aim In our enquiry we are going to investigate how the Breamish's Characteristics change from source to mouth. We are going to see which aspects of the river will change. The aspects that we will be measuring are going to be whether or not the velocity, bedload, bedload shape or width will change as the river travels from the source to the mouth. Identifying questions and issues I have decided to examine and measure the changes in the rivers velocity, width, rock classes. I will be measuring these as different points downstream. We will be split into different groups, some will be measuring at the source, some at the mouth and some half way in-between. I am expecting that the rivers velocity will increase from the source to the mouth. The river will become faster flowing because of erosion, which will cause the bedload to become smoother, this means there is less friction acting on the water. This will make it flow faster and more freely. I predict that the river will become wider from the source to mouth. My reasoning behind this is that lateral erosion will cause the banks to wear down, meaning that the river will become wider as the river moves downstream. The final thing that I have decided to examine from the source to the mouth is the rock classes. I will examine the rocks at the all the different sites, I will be using a chart to mark down which class they are.
Water flows faster and is deeper on the outside edge of a meander curve
Geography Coursework Introduction - Aims and Objectives Purpose of study and general theory The purpose of this study is to decide whether the hypothesis 'water flows faster and is deeper on the outside edge of a meander curve' is true or not. To do this I have collected a lot of data about the river Wye. I will use this data such as bed load samples, width of the river depth of the river to create cross sections, velocity (measured in 2 different ways), and gradient. I will also use field sketches and maps of the areas. The field sketch on the following page shows Group 3, Site B. This is an example of a hand drawn map of the area that we studied. In it there is all the relevant detail that we could see these are things like where we saw the biggest sediment, if there was any overhanging branches or vegetation at the edge of the river. We also identified if it was possible (in some cases we couldn't see) where the fastest flow looked to be. Other things we drew were pipes and that were intercepting slightly with the river's flow. I think that many people would be interested in and benefit from this study. People such as younger students who want to know about rivers and how they work, or even just to find out how to study the river. It would also be of interest to anyone who has a particular interest in geology or it could even be to the interest of the Buckinghamshire
For One Named Drainage Basin, discuss the Strategies and the Benefits of River Restoration or Ecological Management.
For One Named Drainage Basin, discuss the Strategies and the Benefits of River Restoration or Ecological Management. The restoration of the Kissimmee river in Central Florida began in 1999.After a severe flood in the 1940's a strategy was implemented in 1962 to use channelisation to straighten a 90km long drainage canal. Within the canal, there were storage lakes and various water control features. The aim of channelisation was to straighten the river, which reduced the length from 160 to 90 kilometres the effect of this is an increase in discharge and reduced flooding on the floodplain as water stayed in the drainage basin for eleven days and channelisation reduced it to one day. It was designed to control the river and prevent flooding. The channelisation had many effects on the ecosystem, which meant that its biodiversity decreased, for example, loss of wetland habitats causing 92% fewer birds in winter. Two thirds of the floodplain wetlands were drained and the nutrients were no longer absorbed. This had severe effects on the hydrosere such as the vegetation cover however; they quickly noticed that the wildlife habitats were being severely affected. As a result, the river had become stagnant thus causing a loss of animal species. It was finished in 1971 but four years later in 1975, the Kissimmee Restoration Act was passed to help the area to be sustainable both
Landforms located along the River Tees, County Durham
Landforms located along the River Tees, County Durham The River Tees is not necessarily one of the most famous rivers in the United Kingdom, but in its relatively short passage to its mouth from its source in the marshy moors of the Pennine Hills, the river produces a diverse array of landforms, which vary as it progresses downstream through its drainage basin. Beginning in a saturated moor as a mere trickle of water over 600m above sea level, it emerges progressively larger, producing waterfalls, gorges and V-shaped valleys with interlocking spurs in its upper course, meanders and oxbow lakes in the middle course and flood plains, levees and deltas as it reaches its mouth. In the upper course of the River Tees, the steep gradient of the land results in vertical erosion, mainly through abrasion and hydraulic action to be the dominant process occurring with the river at this stage. The Tees starts from its source in a saturated moor in the Pennine Hills. The abundant water trickles downwards, due to the high gravitational potential energy it possesses, which can be converted to kinetic energy due to the steep gradient. These mere trickles of water develop into the River Tees. Various tributaries add to the volume of water and the river uses its abundant kinetic energy to vertically erode away at the bed and banks, with its steep gradient encourages erosion vertically
If bed load size decreases downstream with distance downstream.
Avery Hill GCSE Unit 2: Water, Landforms And People Introduction (draft) The main idea of my investigation is to study if bed load size decreases downstream with distance downstream. I will be studying 3 areas of the River Usk. The River Usk is 5.5 km long but my investigation will only study 2km of the river. The river begins with many meanders but further downstream it straightens out and then meanders again. On the edge of the river side the land had been eroded (undercutting) and the land was soft clay. The weather on the day of study was sunny with a slight breeze. There was some vision of human activity in the drainage basin; there were quad bike skid marks and farmers. If the river basin is used for investigation as the discharge level can be studied better as we could enlighten whether discharge was more or less nearer tributaries. Discharge is the amount of water, which is added from tributaries, which makes the water energy faster. Further downstream more sources (tributaries) will add to the river. The river will get faster and attrition will occur which causes the bed load to become smaller and rounder. The largest size a river can carry is competence. The largest quantity is capacity. Upstream there are larger rocks but as discharge rises rocks decrease in size further downstream. I believe that the discharge is slowed down due to many rocks being
