What are the problems of managing a river? Socio-economic and environmental needs?

What are the management challenges associated with the development of river landscapes?

Lesson Objectives: By the end of the lesson you will be able to: Identify why management of river basins is needed in MEDCs and LEDCs. Describe management methods used in MEDCs and LEDCs. Discuss the sustainability of the river management strategies.

Managing development of river basins in Britain Britain has 4.3 million people living in flood-risk areas and 1/3 of the area earmarked for new housing development is on floodplain land. £240 billion worth of housing, economic assets and infrastructure is vulnerable to flooding. 1:10 new houses are being built in similarly risky places. 1/10 Britain’s houses are on floodplains, and many of the 3 million new homes the government want to see built by 2020 are in risky areas. Is there an alternative?

Managing development of river basins in Europe Germany In 4 main regions tough planning laws have been set. A planning application will not even be looked at if it does not include reservoir facilities. Holland 60% land is below sea level. £9 billion has been invested in raising and strengthening dykes over the past decade. New strategy of ‘living with the water’ – reallocated 1.2 million acres of dry land as flooding zones. In some areas they are building permanently floating homes on the floodplain.

Case Study: Managing the Thames, Oxford Small area and great pressure for residential and industrial development. Area prone to flooding because: Low lying area. Water from a large area drains into two major river which meet in Oxford. Agricultural activities increased risk – trees and hedges have been removed. Area is clay – impermeable. Large developments on floodplain – impermeable surfaces= less infiltration. Urbanisation – how could this reduce the risk of flooding?

Management Strategies Areas liable to flooding given over to farming, recreation and allotments. Flood relief channels, channel dredging and flood prevention schemes have resulted in localised declines in peak flood levels. Levees, channel scour and straightening have all been used.

Proposed flood management strategies Flood Relief Channel The Environment Agency concluded the most effective solution would be a 8km long, 25m wide flood relief channel from River Thames at Binsey to Sandford Lock. £100 million flood relief scheme could see Oxford bypassed by a water channel. However this impacts on the Oxford Meadows Special Area of Conservation. Because of this and the cost = no longer considered an option. Water storage areas Craetive 4 large water storage areas beside the Thames and Cherwell north of Oxford. Consist of large areas of farmland that would be allowed to flood.

Are these plans sustainable? Is it worth trying to protect against flooding?

Case Study: Managing flooding in Bangladesh It is impossible to prevent flooding in Bangladesh. The Flood Action Plan attempts to minimise the damage and maximise the benefits of flooding. Relies upon huge embankments (levees) which run along the main rivers. Estimated $10 billion – could take 100 years to build. However they are not able to withstand the most severe floods, but will control some of the flooding. Embankments are set back form the river to protect them from the erosion of the river.

Disadvantages 1.Increased time of flooding as embankments prevent back flow into river. 2.May increase risk of flooding downstream. 3.Not enough sluices have been built to control the levels of the floodwaters in rivers. 4.Sudden breach of the embankments may also deposit deep layers of infertile sand reducing soil fertility. 5.By preventing backflow into the river, areas of stagnant water will be created = disease. 6.Decreased flooding will reduce number of fish – food source. Are MEDCs more vulnerable to floods than LEDCs?

Homework Plan this essay: With reference to named examples, explain the ways in which human activities might lead to conflicts in river environments, and examine what is being done to reduce such conflicts.(25) Due: Wednesday 16 th December