Dam Synchronisation and Flood Releases - agriwaterpedia.info

DAM SYNCHRONISATION AND FLOOD RELEASES IN THE ZAMBEZI RIVER BASIN: ANNEX 4 OF FINAL REPORT
SUPPORT THE COORDINATION
OF FLOOD RISK ZONING INITIATIVES
Intervention 4.6 Timeframe: Short term Budget range: < 0.5 M USD for
Sheet #
coordination of
initiatives
Linkages: Annex 4, Chapter 6
Concept:
Improved flood protection through flood risk zoning can replace flood protection through dam
management or extra dams.
Purpose:
Justification:
Actions/
Responsibilities:
Benefits/
beneficiaries:
Means of
implementation:
Specific
assumptions/
risks:
Comments
Flood risk zoning can serve for regulations for new settlements, current land use practices and
rescue and warning.
Flood risk zoning coordination at a river basin scale can make efforts of flood risk zoning on a
national or local scale more cost efficient and effective. For the areas downstream of the dams,
flood risk zoning can improve continuous awareness that dams can spill and therefore cause out
of season flooding and/or sudden rise of flood levels. Their are current initiatives in parts of the
catchment that each apply different metionds: for example UNOSAT for flood mapping in parts
of Mozambique and Caprivi strip for rescue and warning, UN Habitat in Mozambique for new
settlements, International Federation of Red Cross for vulnerability assessment for rescue and
warning, FEWS Net for early warning, ZRA around Kariba dam to influence current land use
practices and new settlements.
Coordination of different flood risk zoning initiatives currently being
developed independently in different riparian countries; further
identification of the benefits and limitations of coordination and the
possibilities of innovative techniques.
Flood risk zoning efforts can contribute to a combination of:
Prevention: zoning to set rules for new developments;
Preparedness: zoning to give advice or set rules for land use practices
and for awareness raising among current inhabitants
Warning and rescue: risk zoning to use during emerging flood events
to set priorities
Coordination between current mapping activities in the Zambezi River
Basin is a first and useful step in Risk Zoning that will also benefit flood
forecasting and involvement of international relief organisations during
floods as well as the understanding between neighbouring countries.
ZAMCOM /
SADC Secretariat
to coordinate,
Member States to
commit.
Residents in
floodprone areas.
Disaster
Management
organisations,
Surveyor
generals,
Ministries of
Water
ZAMCOM / SADC Secretariat to organise workshop between different initiatives, possibly in
combination with FEWS Net.
Flood risk zoning rules for new settlements or for current land use and awareness raising only
makes sense as an investment if such a system will be respected by local inhabitants. If flood risk
zoning is introduced as a ‗rule‘, legal experts and local governments have to be able to ensure
compliance, which has proven to be difficult. Flood risk zoning for flood insurance is not a
viable option in the Zambezi Region because the economies of the region have not developed
well enough to create a market for such insurance and because the data availability prevents
good risk calculations.
Data availability in the region for flood risk zoning is limiting the possibilities for flood risk
zoning. A map of maximum flood extents, however, is easy to compile and is useful.
Fortunately, only a small level of investment would be needed for the production of such a map.
Mapping of flood frequencies, on the other hand, is more difficult. For example, the flood risk
zoning around Kariba, where a distinction is made of zones for multi-year crops and seasonal
crops, can be copied to other locations. However, it must be noted that in many floodprone
areas in the basin local people have already adapted such approaches without any official flood
risk zoning, but have decided that there are little viable options for them to move elsewhere.
The current developments in remote sensing will contribute significantly to improved and less
costly flood risk zoning in the near future.
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