Universitätssiegel
Projct Partners

Prof. Dr. Bernhard Eitel
Samuel O. Ochola
 

Forschungsprojekt

Integrated Flood Hazard, Risk and Vulnerability Assessment in Nyando Basin, Kenya: Options for Land Use Planning

Nyando Basin located in western Kenya, East Africa (fig 1), is situated on the equator at 35°10’E and covers 3,618 km2. Altitude varies from 1000 - 2000 m a.s.l. The catchment has a steep gradient upstream but gentle downstream in the Kano plains where the river dissipates in a wetland area and finally discharges into the Nyakach Bay, Lake Victoria. Over 5,000 people are affected every year by floods in the area. The average annual damage is about US$ 850,000 with annual relief and rehabilitation measures costing US$ 600,000 in the Kano Plains.

Major floods occurred in 1937, 1947, 1951, 1957-1958, 1961, 1964, 1985, 1988, 1997-1998, 2002 and 2003. However, Nyando Basin continues being flooded every year during long (April-June) and short (October-November) rainy seasons.

A unique feature of floods in the Nyando Basin is that most of the runoff is generated in the upper catchments which receive much higher rainfall than the plains downstream, taking the population in the plains unawares. Low areas around the mouths of the river are inundated for weeks. The worst affected are the poor inhabiting the flood plains and riverine lands to earn a living from agriculture, livestock keeping and fisheries. Because of poverty, poor rural infrastructure and other factors, they are the most vulnerable to floods.

The floods severely limit and hamper developmental processes of the rural societies thereby perpetuating and increasing the incidence of poverty. Stagnant floodwater also causes vector borne diseases, which result in high incidence of morbidity with consequent loss of alternative employment opportunities. Pollution of drinking water sources like wells and tube wells, bank erosion, silting of river beds and consequent lateral shifting of river channels, and cutting down of trees for firewood around relief camps are some of the adverse environmental impacts of floods in the Nyando Basin.

Objectives

  • to review previous relief and coping efforts
  • to map the extent of flooding prone areas in order to construct hazard zonation maps
  • to assess the vulnerability of all the individual elements of risk in order to construct vulnerability and related maps and risk maps.
  • to carry out a participatory community-based vulnerability assessment in order prioritise community ranking to future flood management projects
  • to suggest sustainable alternative basin land use planning tools focusing on vulnerability and poverty reduction
  • to develop a practical land use map for the basin that will reduce community vulnerability
  • to present various affordable alternative house construction designs that are less vulnerable to floods while adhering to community needs and sustainable development.

Relevance of the study

  • Prevention & management of flood and related disasters, risks and vulnerability reduction.
  • Policy, public commitment and institutional frameworks such as legislation and organisational development for national and local decision-making
  • Promote use of local knowledge in reducing vulnerability to floods
  • Transfer flood hazard assessment results to land use planning and action, poverty reduction participatory projects (Financial and economic tools) and less vulnerable housing
  • Environmental management in the wider basin, land use planning – household, community, local, basin-wide and national government
  • Protection of critical facilities
  • Networking and partnerships, early warning systems, mitigation, information dissipation and living with floods
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Letzte Änderung: 08.07.2019
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