• 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. 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.

  2. River channel processes.

    In turn this could cause; - Blockage of gravel i.e. fish can't use the ravel for spawning ground. - Leaching and eutrophication could occur - The sediment could block up smaller rivers and so increase the risk of flooding, i.e.

  1. How does Loughton Brook change as it moves downstream?

    The roundness total for 5 started off high at the first site and then there was a sudden decrease. Then after that decrease there was a gradual increase in them. This shows that an anomaly occurs at site 1 as there cannot be a very high amount of pebbles there.

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

    This justifies the discrepancy between the values and the percentage difference is small enough for the experimentally calculated discharge to be valid. The height of water level experimentally measured at intervals of 10m is shown below. The first measurement was taken 20 away from the end of the gate, as

  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. Geography investigation - The River Skirfare located in the Littondale region in the Yorkshire ...

    Again, for purposes of presentation quality the data will be split based on which hypothesis they refer to. * 'Bedload will decrease in its size and angularity downstream'. Firstly I shall display the data concerning the size and shape of the material at each location on the river Skirfare in tables as it was taken at the locations.

  1. Do the Characteristics of a river change downstream?

    From source to mouth, the River Wharfe is approximately 60 miles long. The site of our experiment lies in the centre of Ilkley close to a bridge so that we are able to study both sides of the river without having to wade through the river.

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

    It doesn't just suddenly change from one section to another so it is hard to collect the right information at each site. It is also hard to get an accurate reading with the gradient by using the clinometre, as you need a steady hand and someone that is the same size to enable you to get quite a good result.

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