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ZAMBIA PRESENTATION AT THE
WMO CONSULTATIVE MEETING
HELD AT MAPUTO, MOZAMBIQUE,
1- 5 DECEMBER 2009
presented by
J. NKOMOKI (ZMD)
P. CHOLA (DWA)
Zambezi headwaters in Zambia
Upper Zambezi channel in Angola
Presentation Layout
1. Legal and Institutional Framework
2. Organisation responsible for FF & Disaster Preparedness
3. Organisations Responsible for Flood Management
4. Institutional and Human Capacity
5. Data Exchange and Sharing Policy
6. Type and Quality of Data
7. Meteorological Products Provided
8. Products by NMS used by NHS and Cooperation
9. Methodology Used for Flood Forecasting
10. Users of Forecast
11. Forecast Dissemination Mechanisms
12. Warning Lead Time
13. Role of FF and EW in Reservoir Operations and Management
14. Community Participation
15. Major Flood Events in the Last 20 Years
1. LEGAL FRAMEWORK
The Zambian legal framework assigning flood
forecasting/flood management and /or disaster
preparedness are as follows:
(i) Water Affairs Dept (Water Act 1949);
(ii) Zambia Meteorological Dept (Government
Gazzete Notice, 1992)
(iii) Zambezi River Authority (ZRA Acts No. 17 Zambia
and 19 Zimbabwe);
(iv) Disaster Management and Mitigation Unit (DMMU
Act/Disaster Management Policy)
2. Organisations Responsible for Flood
Forecasting and Disaster Preparedness
Agencies responsible for flood forecasting and
disaster preparedness include the following:
DWA, ZMD, ZRA, DMMU and ZESCO.
3. Organisations Responsible for Flood
Management
• Organisations responsible for flood management
include:
►NHS, NMS, ZRA, DMMU, Defence Forces, Local
Councils
• No flood policy but there is the National Disaster
Policy and the operational manual that relate to
Flood Forecasting
4. Institutional and Human Capacity
The current institutional capacities are limited in terms of
numbers of skilled personnel and specialised equipment.
There is need to improve in the following areas:
(i) Forecasting skills. Currently there is a limited number of
personnel with forecasting skills at ZMD, ZRA and
ZESCO. One Telemetry Technician exists at ZRA.
(ii) Retention of skilled personnel. This is a challenge to due
unattractive conditions of service.
(iii) Restructuring and voluntary separation programme. Both
public and quasi-government institutions lost essential
personnel due to the reorganisation.
(iv) Lack of forecasting tools. Acquisition of models is a
challenge and maintenance of data collection network is
another.
(v) Inadequate data collection network. This applies to all
agencies.
5. Data Exchange and Sharing Policy
• Existing policy on data/information exchange is to
provide this information at a fee.
• Government, learning and research institutions are
exempted.
• Limited data/information is available free of charge
on MEWD (www.mewd.gov.zm), ZRA website
(www.zaraho.org.zm).
• Data/information is shared freely on projects
involving DWA, ZMD, DMMU and ZRA and
participation as part of their contribution.
6. Type and Quality of Collected Data
Zambia has four basic data collection networks:
hydrometric, meteorological, telemetry and
water quality networks.
• Type of data collected:
- Hydrological (stage flow and water quality);
and
- Meteorological (rainfall, temp, evaporation,
humidity etc),.
• This of good quality for flood forecasting
purposes.
ZRA Hydrologic / Water Quality Monitoring Network
Frequency
of sampling
(WQ)
Hydrometric network
ZMD Station Network …38 Stations
2.1 Strengthening Hydrological Network Budget
ANNUAL TARGET 2009 BUDGET RE LEASED BALANCE REMARKS
OBJECTIVE (US $) (US $) (US $)
To To Provincial
strengthen maintain 104,000 69,333 34,667 distribution of
the existing and gauging
hydrometric rehabilitate stations:
network in 179 Central 18 (1)
order to gauging Copperbelt 17 (1)
enhance data stations Eastern 14 (2)
collection for across the Luapula 16
planning and country. Lusaka 16 (1)
decision Northern 33 (1)
making. Northwest 25 (1)
Southern 19 (2)
Western 21 (2)
Total 179 (11)
179 stations is the current strength of the national hydrometric network. The network has been expanding since 1986
after suffering from the reduction due to IMF’s Structural Adjustment Programme (from 250 to 50 stations). This
includes the SADC HYCOS nodes as per original design criteria. In the provincial distributions, bracketed numbers
are the SADC HYCOS stations.
Data Loggers will be installed one each in Southern and Western Provinces all in the Zambezi Basin.
7. Meteorological Products Provided
• Daily, 5-7 Days, 10 Days (Decadal Crop
Weather Bulletin) and Seasonal Rainfall
Forecasts (SRF)
• Weather forecasts are communicated through
e-mail, TV, Community Radio stations
(RANET), HF radio Tranceivers, Phone
• SRF forecasts are communicated through
workshops, email, National Agricultural
Information Service (NAIS) phone, RANET,
DMMU Donor Advisory meetings.
8. Products of NMS Used by NHS
• Mainly Daily Rainfall, 5-7 days, 10 days weather
SRF and 10 days crop weather bulletin
• Exists strong Cooperation between ZMD and
DWA
Example of NMS products
Rainfall in mm
M
w
in
ilu
ng
S aM
200
400
600
800
1000
1200
1400
1600
0
ol
w et
e
Za z i
m Me
be t
K zi M
al
ab et
o
M M
on et
gu
K
ao Me
m t
S
es a M
he et
ke
M Me
ba t
K la
as M
a e
M ma t
is
am Me
fu t
A
M gr
K pi o
aw ka
am M
bw et
a
M M
an et
sa
N Me
d
Total
K ol a t
af
iro Me
nd t
a
K
ab Me
w t
Normal
K eM
ab
Meteorological Station
w et
e
S
Total Rainfall Upto 10 February 2007
er Agr
Lu en o
sa je
M
Lu ka e
sa I A t
ka irp
M or
ou C t
nt Air
M po
ak rt
Meteorological Department)
ul
C u
hi
pa Ag
P ta
M eta Me
ag uk t
oy e
e M
A et
g
C rom
Li
ho e
vi ma t
ng
st Me
on t
e
M
Total Rainfall Up to 10th February 2007 (Zambia
et
Cumulative Rainfall (ZMD)
(11 July, 2006 to 10 February,2007)
2006/2007 Above Normal Rainfall
Most northern and eastern met stations had
received February 2007 rainfall above
1000mm:
- Chipata = 1348mm
- Mwinilunga = 1304mm
- Ndola = 1192mm
- Misamfu = 1191mm
- Kasama = 1117mm
2007 Flash Flooding Washed Away SADC HYCOS and
Gauging Equipment Due to Normal and Above Normal
Rainfall
Luangwa River Water Levels (m)
Date Water Level (m) Discharge
(m³/s)
13/02/2007 9.505 5,430.61
14/02/2007 9.255 5,062.61
15/02/2007 8.896 4,561.51
Flooding of Police Camp at Luangwa
River at Great East Road Bridge, 2007
Police Camp,
February 2007
Matongo Platform (2 - 330); Water Level Comparison of High Flood Years
(ZRA,2007)
1957/58
1958/59
8 1961/62
1962/63
1963/64
1964/65
7 1967/68
1973/74
1974/75
1977/78
6 1987/88
1997/98
2002/03
Water Level (metres)
2004/05
5 2005/06
2006/07
4
3
2
1
0
1 15 29 43 57 71 85 99 113 127 141 155 169 183 197 211 225 239 253 267 281 295 309 323 337 351 365
October - September (Days)
Comparison of Water Levels at Matongo Platform for
Decision Making: 1963,1968 and 2007
Matongo Platform (2-330); Water level Comparison for February
1963, 1968, and 2007
7.2
7
6.8
Water Level (metres)
6.6 1962/63
1967/68
6.4
2006/07
6.2
6
5.8
5.6
1 3 5 7 9 11 13 15 17 19 21 23 25 27 29
February
Interpretation of
Flooding Effects of
2007 Flows at Matongo
To explain to the ordinary
people what the 2007 floods
would be is to liken it to what
happened in 1963 and 1968
when the Kazungula ferry
docking point was submerged
or when father of Muyakwa’s
homestead was flooded
together with his maize fields.
However, God gave us good
fish catches those years!
Barotse Plain in Zambia provides natural flow
attenuation and sediment deposition
Flood Forecasting
The DWA, ZMD, ZESCO and WWF developed the
Kafriba Model for flood forecast in the lower
Kafue Basin in an integrated manner.
The DMMU, DWA, ZMD, CSO and Planning Dept of
MEWD are developing Community Multi Hazard
Early Warning System (relate the river stage to
areas of inundation in the neighbouring
communities).
DWA uses the HYDATA model for general
hydrological data processing and flooding
trends are usually related with rainfall forecasts.
9. Methodology Used for Flood Forecasting
DWA and ZMD do not have FF modelling tools. ZMD
produces and issues daily, 5-7 days, 10 days
weather forecasts and SRF outlook from where FF
is inferred.
• ZRA uses two methodologies for flow forecasting;
Index-Variable and Exponential Decay curve.
• Index-Variable method is used for the rising part of
the hydrograph (wet season). Full details of the
forecast model are contained in the report by
Shawinigan Engineering under SADC AAA 3.4
Project: “Wet Season Flow forecasting for Victoria
Falls and Kariba.
• Model gives one month lead time for flows at
Victoria Falls. The lead time between Victoria Falls
and Kariba is approximately two weeks
Wet Season Model
The relationship between Vic. Falls flows and
upstream observations is as follows:
QVF = C1Qch+C2Pma+C3Qwa+C4Qka+DPcum+E
Where QVF = Monthly flow at Victoria Falls for the given month
Qch = Monthly flow at Chavuma for the preceding month
Pma = Stage at Matongo Platform for the preceding month
Qwa = Monthly flow at Watopa for the preceding month
Qka = Monthly flow at Kalabo for the preceding month
Pcum = Cumulative precipitation over the catchment below Barotse Plain
C1,C2, C3, C4, D and E are constants
Sample Forecast: 2008/09 Season
Input Month Forecast Forecasted Observed %Variance
Month Flow Flow
(m3/s) (m3/s)
December January 888 811 9.5
January February 1426 1328 7.3
February March 3268 3358 -2.7
Dry Season Forecasting
• Dry season forecasting procedure employs the
exponential decay curve for ground water
release
• Application starts with the “onset” of confirmed
recession of floe hydrograph when surface
storage depletion diminishes
Dry Season Model
Monthly mean flow are computed from the
following equation:
Qt = Q0(1-e-άt)
άt
Where Qt = Forecasted monthly mean flow
Q0 = Mean flow of preceding month
ά = Modified recession coefficient for the month
10. Users of Forecasts
• Forecasts are used for all sectors, the general
public . Yes, some communities use forecasts
but decision makers not much.
• Forecast product acts as one of the inputs into
the water balance model for Kariba reservoir
whose results are used by the power utilities and
downstream communities, DMMU and HCB
• Results include EOM level, spillage amounts,
available water for power generation at specified
target
11. Forecast Dissemination
Mechanisms
• Forecast are disseminated through various
means:
• Letters (normal)
• Press releases (normal/emergency)
• Phone (emergency)
• E-mail (normal/emergency)
• Personal visits (emergency)
• TV, Fax, RANET, NAIS, Workshops
12. Lead Time
• Lead time depends on whether it is normal
situation or an emergency, otherwise it is
sufficient for planning purposes.
• In normal situations, At least two weeks
lead time is given
• In emergency situations lead time may
reduce to as little as one day
• Procedure to be followed in flood situation
is well documented in the SOP for Kariba
dam published by ZRA and DMMU
manual
13. Role of FF & EW in Reservior
operations
IFM Strategy for Kafue Basin
This is mainly done through the
Power utility company ZESCO for
managing dam water levels
(Spillage)
14. Community Participation in
Preparedness
Due to recurring Floods in Zambia,
communities are steadily becoming active
participants in preparedness against flooding
(During Spillage informed; via RANET/
Advisory satellite disaster Management
committees)
15. Major Flood events
during last two decades
Typical Floods of 2006/7, 2008/9
were well captured in the
seasonal climate outlooks issued
by ZMD
Flood Events of Last 20 Years
Season Peak Flow (m3/s) Annual Means (m3/s)
1997/98 3438 1104
2000/01 3575 1227
2003/04 4340 1339
2006/07 4568 1475
2000/08 3247 1321
2008/09 5651 1521
1957/58 9436 2328
1977/78 6172 1889
DAM SAFETY & MONITORING
Thank You
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