• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

Engineering options available to prevent flooding

Extracts from this document...

Introduction

Engineering options available to prevent flooding The flooding of rivers is a natural and essential part of river basin processes and is only a hazard because they can affect people's lives. Flooding occur when a large volume of water enters a river system quickly and cannot be contained within the river channel. By analysing a river basin carefully we can learn and predict how likely it is to flood. This information can be used to reduce the damage caused by such events, or perhaps even to modify future events themselves. Engineering structures impose the most response and cause to flood hazards. The term 'flood protection' is a misleading term, as protection is only as good as the design of the protection scheme itself. Once a flood protection scheme is breached the damage is likely to be greater, causing damage to buildings and surroundings, which can be very expensive and harmful. River management schemes concentrate widely on reducing flood losses, rather than preventing flooding altogether. ...read more.

Middle

Channel Improvements Channel improvements are structured to confine floodwaters to the river channel in one of two main ways: * Channel roughness can be reduced by clearing vegetation and other obstructions in the course of the river channel. This creates a lining of the channel with a smooth surface such as concrete, which reduces friction and allows discharge to pass as a more easier and quicker rate. This type of scheme can help the flow of the discharge however it may intervene with the channel discharge downstream. * The channel can be widened or deepened by dredging. This increases the capacity of the channel. The disadvantages of these schemes are that maintenance for them is often ended as the river tries to revert back to its natural course. Relief Channels Channels can be shortened by cutting meander loops and increasing the gradient to discharge water away from the area at risk, much quicker. ...read more.

Conclusion

This could be achieved by constructing a flood control weir that would raise water levels upstream during flood conditions, or by constructing embankments around the edge of the floodplain, which would create a storage reservoir to hold water for a longer period of time. The following five schemes were investigated: 1. The construction of floodwalls and embankments at Crosthwaite, and in vicinity of Great Bridge. 2. Removal of the weir at Great Bridge and local re-grading. 3. Re-grading the channel for approximately 400m upstream. 4. Widening of the channel for approximately 350m upstream. 5. Both re-grading and widening of the channel. Scheme 1 The scheme was used as a base with which to compare other schemes. It is probably unrealistic as it is likely to result in peak river levels upstream of great bridge up to 450mm higher than those during the flood of December 1985. Floodwalls and embankments would be built out of stone with reinforced sheet pilling at certain locations. They would be designed to contain floods to a level predicted to occur only once in 100 years. ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our AS and A Level Hydrology & Fluvial Geomorphology section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related AS and A Level Hydrology & Fluvial Geomorphology essays

  1. Hydrology and Fluvial geomorphology. (Q&A)

    Finally, the amount of water stored as ice and snow depends on global temperatures. There is growing evidence that global warming caused by human activities is now causing these surface stores of water to melt, returning their water to a liquid form.

  2. Describe and explain the physical and human causes of flooding and the possible solutions ...

    In this flood case, 34 died, 1000 were made homeless and 90 buildings were destroyed. Solutions: For major flood situations, solutions need to be at hand and they also have to be very reliable as human lives may depend on it.

  1. 'How does the risk of flooding vary along the course of the River Eea?'

    Site Two is at High Cark Bridge (see fig. 3). The land here has been altered by man so it can be used for agriculture. Farmer's cattle graze on improved farmland. The farming here is extensive rather than intensive meaning the land more land is needed to support fewer cattle

  2. River channel processes.

    The difference in colour of the beds is caused by the small amounts of minerals in the rocks. MEANDERS - these are the sweeping curves found in the river's natural course. They are mainly formed by the sweeping nature of the thalweg in the river.

  1. To what extent the flood alleviation scheme has had on the environment and people ...

    This risk is increased if it rains after snowing as the ground is still frozen and impermeable. Sandstone and limestone are rocks that are permeable. Granite is an impermeable rock type. As with rocks you also have permeable and impermeable soil, for example, sandy soils are permeable whereas clay soils with not let water infiltrate it.

  2. Hard & Soft Engineering

    This is where a meandering river has a new straighter channel cut, to provide a shorter and alternative route, often this new channel is concrete lined to aid flow and reduce flooding. Realignment also steepens the gradient of the river and aids navigation for boats and water-borne craft. Levees.

  1. Fluid Dynamics - Free surface profiles in an open channel.

    The fluid flow is from left to right, with the supply to the flume being gravity driven. A weir at the downstream end of the flume controls the flow. The sluice gate is provided with stagnation tubes, facing directly upstream, these are filled with a colour dye such that the

  2. Do the Characteristics of a river change downstream?

    also high erosive energy which in time will help to erode the bedload. On account of the fast flowing water and steep, narrow valley sides the stream is noisy and turbulent as a result. River Wharfe - The lower/middle course of the river.

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work