Managed flood releases from reservoirs to restore and conserve downstream floodplain ecosystems and their dependent livelihoods

1
(No Transcript)
2
(No Transcript)
3
(No Transcript)
4
(No Transcript)
5
(No Transcript)
6
(No Transcript)
7
(No Transcript)
8
(No Transcript)
9
(No Transcript)
10
(No Transcript)
11
(No Transcript)
12
(No Transcript)
13
(No Transcript)
14
Managed flood releases from reservoirs to restore
and conserve downstream floodplain ecosystems and
their dependent livelihoods

15
Institutional links

• Funded by DFID
• Contribution to World Commission on Dams
• Guidelines to be published by World Bank

16
UK team

• Centre for Ecology and Hydrology
• Natural Resources Institute
• Liverpool School of Tropical Medicine
• Gibb Ltd
• University of York

17
Case studies

• Senegal Valley - M Diop
• Indus delta - T Qureshi
• Kafue - H Chabwela
• Phongolo - C Bruwer
• Tana - S Njuguna, C Mutero
• Mahaweli - K Mathritalike

18
Additional material

• Waza-Logone, Cameroon
• Hadejia-Nguru, Nigeria
• Diawling Park, Mauritania
• Colorado, USA
• LHDP, Lesotho

19
(No Transcript)
20
Senegal, West Africa

• release hydrograph designed to flood 50,000 ha
• turbines may change priorities
• human and animal health problems

21
(No Transcript)
22
Phongolo, South Africa

• Flood mechanism complex
• Initial floods wrong time of the year, crops
  washed away or rotted
• Water committees farmers, fisherfolk, livestock
  keepers, women, health workers

23
(No Transcript)
24
Indus delta, Pakistan

• Port protection, shrimp nursery
• Mangroves 0.028 m3s-1 per 40 ha
• Fisheries flood peak 850,000 m3s-1
• Floodplain forests flooded 15 yrs
• Solution complex, impossible ?

25
(No Transcript)
26
Mahaweli, Sri Lanka

• Irrigation schemes complex, old, expensive to
  adapt
• Sediment flushing blocked canals

27
(No Transcript)
28
Kafue, Zambia

• Biodiversity lechwe
• Recession agriculture dry season flows too high
• Institutions own priorities

29
(No Transcript)
30
Tana, Kenya

• Dams in headwaters, distant from target
  floodplain
• Release depends on intervening flows/rainfall

31
(No Transcript)
32
(No Transcript)
33
(No Transcript)
34
Waza-Logone, Cameroon

• PRA people want floods
• Pilot floods test release options

35
(No Transcript)
36
Hadejia-Nguru, Nigeria

• Economic valuation floodplain more valuable
  than intensive irrigation
• Test releases outlets small

37
(No Transcript)
38
Diawling Park, Mauritania

• 1 July sluice opened to dampen soil, simulating
  rainfall
• 1 August releases max 1 cm per day growth of
  grass keeps pace
• annual fish production increases with flooded
  area approx 100 kg ha-1.
• 14 September salt leached from soil water drains
  off to prevent typha

39
Fish production/flood area
40
(No Transcript)
41
10 steps - flow chart
42
Water and the EnvironmentIssues for Help

• Objective setting
• Data
• Hydro-ecological science
• Ecosystem management
• Feasibility

43
Water and the EnvironmentObjective setting

• What sort of environment do we want?
• Natural or managed?
• Science or social choice?
• Stakeholder participation

44
Water and the EnvironmentData

• National networks for rivers, groundwater
• Few data for wetlands
• Biological recording very poor

45
Water and the EnvironmentHydro-ecological
science

• Water/species linkages
• Hydrological functions of wetlands
• Integrated hydro-ecological models

46
Water and the EnvironmentEcosystem management

• How much water? not the right question
• Alternative scenarios
• New ideas - managed floods

47
Water and the Environment Feasibility

• Dam design
• Flow forecasting
• Opportunity costs
• Equitability of resource use

48
Guidelines for managed flood releases from
reservoirs

• Feasibility
• Design
• Implementation.

49
Level 1- feasibility

• 1 define objectives for flood releases
• 2 assess the technical and financial feasibility

50
Level 2 - Design releases

• 3 define flood needs of ecosystem
• 4 define flood release options
• 5 assess impacts of options
• 6 choose best option

51
Level 3 - Implement

• 7 establish co-ordination mechanisms and
  legislation
• 8 implement structural changes to the dams and
  floodplain
• 9 make (test) releases
• 10 monitor, evaluate and adapt management
  programme

52
(No Transcript)
53
(No Transcript)
54
Project outputs

• Literature survey
• Issues
• Problems and prospects
• Case studies
• Ten steps guidelines
• Dissemination workshops