• 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)

    Condensation of that water vapour as clouds leads to precipitation (rain, snow, hail, dew etc), a vertical transfer down to the surface of oceans and land . The terrestrial, or land-based, part of the system is what interests us most for thinking about water resource issues.

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

    For high flood risk areas eg. San Gabriel, Los Angeles solutions have been put to use. The San Gabriel river basin is a high density basin. This means that the rock which the river basin is made out of is very hard and solid so water will not be able to infiltrate into the rock.

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

    Again they show dramatic change in depth and shape of the cross section as we move downstream. This again shows the increase of the efficiency of the river. These 5 graphs can be related to the graphs of the Width so that as the width increases as we move further downstream.

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

    of the valley very quickly because it would have very little time to be soaked into the soil or rocks underneath. This could cause a risk of flooding, as the river may not be able to carry the increased capacity of water.

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

    * Using a pointer gauge the upstream Y1 and downstream Y2 (see Diagram 1) water depths were measured. * The Discharge rate, Q (m3s-1) was measured. The flow was channelled into a tank of known cross sectional area, the time taken for a specific amount of fluid to discharge was measured, using a meter rule and a stopwatch.

  2. River channel processes.

    RIVER VALLEYS - these results from the down cutting of the river as it flows through an area. As it cuts downwards the slopes are subject to weathering and erosion, with mass wasting of the slope resulting. This hence forms the v-sided valley.

  1. 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.

  2. 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.

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