AGRHYMET Regional Centre - Centre Régional AGRHYMET

Permanent Inter-State Committee For Drought Control in the Sahel
Comité permanent Inter-Etats de Lutte contre la Sècheresse dans le Sahel
AGRHYMET Regional Centre
MONITORING Bulletin FOR THE AGRO-PASTORAL CAMPAIGN IN WEST AFRICA
N° 03 - August 2015
Agro-pastoral Situation as for August, 31st 2015
Key messages
The conditions are very favorable for crop growing and rangelands with a calm locust situation.
• The rainfall situation was very favorable in August with above average monthly totals over most of
the region except the bimodal zone that is experiencing its short dry period and in few other areas of
limited spatial extent in the sahelian zone.
• Cereal crops (millet and Sorghum) water requirements are met in the entire sahelian-sudanian zone
of West Africa at the exception of few pockets.
• The locust situation is relatively calm in all the frontline countries. However, given the favorable
ecological conditions in the summer breeding areas, an increase in locust population is possible.
• A significant improvement of the pastoral situation in almost all the pastoral zones was observed
following the increase in available fodder biomass and the filling in surface water bodies.
• Conditions are very favorable to the flows of the major river basin of the region. A decrease in flows
is expected in September, however, floods risks still persist especially in Senegal Basin.
I. Rainfall situation
The rainfall situation was very favorable in August
with above average monthly totals over most
of the region except the bimodal zone that was
experiencing its short dry season (figure 1.1).
Deficits were observed in certain areas of limited
spatial extent where rainfall total is below average.
It is the case of an area in the Southern wilayas of
Gorgol and Brakna, centered in the border zone
common to the two wilayas in Mauritania, the
southern part of Gao region in Mali, the northern
part of Maradi in Niger, an area extending over
parts of Western Batha, Bahr el Ghazal, Hadjer
Lamis, Chari Baguirmi, Mayo Kebbi Est, Western
Mayo Kebbi and Tandjilé regions in Chad, the
northwestern part of Côte d’Ivoire. However,
given the good temporal distribution of rainfalls,
the deficits are not expected to have a significant
impact on the crop growing conditions in the
affected areas (figure1.2).
AGRHYMET Regional Centre PO Box: 11011 Niamey (Niger) Phones: (+227) 20 31 53 16 / 20 31 54 36
MONITORING Bulletin FOR
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Volume 25, N° 03
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The Inter-tropical Front (ITF) seems to have started its Southward retreat during the second decade
of August. However, this should not be considered as a sign of an early cessation of the rains for the
following reasons:
•
•
•
•
The cooling trend of the SST (Sea Surface Temperature) of the Gulf of Guinea is stable, leading to
a strong penetration of the monsoon toward the continent.
In this late August, the ITF is at an average position in the region
The midterm forecasts show high probabilities for moderated to heavy rainfall on the entire region
for the coming weeks
Also, according to the updated seasonal forecasts , average to surplus rainfall is expected in the
entire Sahelian and Sudanian strip for the rest of the season.
Figure 1.1 : Rainfall Estimate total (mm) in August 2015 (source : RFE-FEWSNET)
Figure1.2: RFE total anomaly for the same period in % of 2010-2014 average (source: RFE FEWSNET).
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II. Crop condition
Figure 2: Satisfaction level in water needs for Sorghum in August 2015 (source: SARRAH Model)
As of August
30th, 2015, millet and sorghum
water requirements are met in all agricultural
zones of the region south of the agro-pastoral
zone. The crop water requirements are also met
in the agro-pastoral zone at the exception of few
areas where the requirements satisfactions are
not good. These include the southern part of
Gao region in Mali, the southern part of Kanem
region in Chad, the southern part of the wilaya
of Hodh el Chargui in Mauritania, and an area
extending from the Center of the region of Saint
Louis in Senegal into the southwestern parts of
the wilayas of Brakna and Trarza (figure 2.1).
Moisture conditions are generally favorable to crops
in the entire agricultural and agro pastoral zone of
West Africa. However, a decrease of photoperiod
sensitive crop yield is possible in certain areas,
especially where the factors such as the late onset,
soil saturation and the lack of sunshine are combined.
The rainfall condition is also favorable for maize
(except for flood cases), upland rice as well as for
off-season crops (irrigated and flood recession).
III. Locust situation
Ecological conditions are favorable in the summer breeding areas.
The locust situation is calm in the entire front line countries. The presence of solitarious adults is signaled
in few sites of summer breeding areas in Southern Mauritania, Northern Niger, Chad, and Sudan. In
Northern Mali, no prospection is possible for the time being for insecurity reasons. Elsewhere, isolated
adults have been observed in Southern Egypt, in the Cholistan in Pakistan and near India border.
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The
average
above average precipitations recorded in the northern part of the Sahel in July and
Situation
des to
cultures
August created favorable ecological conditions in most areas of Mauritania and Western Eritrea where
a small scale breeding is possible. Regular prospections should be conducted in those areas to closely
monitor the situation and identify the first signs of increase in locust population. (figure 3).
Figure 3: Occurrences of observed locust presence
Source FAO
Prospections should also be conducted on a regular basis by the Plant Protection Services technical
staff for a close monitoring of other crop pests (spike caterpillars and other pests) and detecting the early
signs of a significant infestation.
IV. Pastoral situation and state of the vegetation
Pastoral situation
The pastoral situation underwent a significant
improvement in the entire pastoral zone. Livestock
watering takes place in surface water bodies filled
by the average and above average precipitations
recorded in July and August 2015. An improvement
of livestock corpulence is observed due to the
increasing availability of the green fodder. There
situation also improves in the Western part of the
Sahel that experienced a prolonged livestock lean
period owing to the significant delay in the onset
of vegetation. Thus, in Senegal, since mid-July,
the good rainfall time distribution has favored the
development of pastures. Grasses phenology varies
from stem elongation to heading out according to the
areas .In the area of Podor, and the Podor-Matam
axis, the rangeland situation is less favorable. In
Mauritania, the emergence of vegetation is in
progress in the entire Agro-Sylvo –pastoral zone
of the country. The presence of densely vegetated
banks is noted in the two Hodhs and in some parts of
the wilayas of Guidimakha and Assaba. Generally,
the pastoral situation has significantly improved in
the wilayas of Assaba, Gorgol, Guidimakha and
the two Hodhs. In Niger, a biomass deficit is noted
in the areas of Tahoua, Tillabéry and North–East
Diffa ; In Chad, a production deficit is possible in
the north of Lac region , in the north of the regions
of Western Batha and Wadi Firra (figure 4.1).
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Figure 4.1 : Potential biomass production in kg.MS/ha at the third decade of August 2015
State of the vegetation
In the agricultural zone of West Africa, the
Normalized Growth Index of vegetation (ICN)
shows areas in Senegal, Mauritania and Niger
that have yet to pass the 40% of the plant growth
potential. Elsewhere, a normal situation is observed
at this start of the last quarter of the vegetation
growth season. In pastoral zone, the ICN indicates
pasture availability over the entire rangelands. It
is important to mention that there are still areas
in Senegal, Mauritania and Chad that are below
40% of the growth potential, where in the event of
an early cessation of rains, a fodder deficit is very
likely (figure 4.2).
Vegetal growth conditions are generally good
everywhere except for few areas of more or less
limited size scattered in Senegal, Mauritania
and Niger (figure 4.3). However, conditions are
expected to improve in these areas during the first
decade of September. Vegetal growth anomalies
show the worst cases in Senegal, Mauritania,
Northern Burkina Faso, and Niger in the region of
Tahoua and in the department of Filingué; in Chad
the situation is similar in the North East of the
Sahelian part of the country and the North of Lake
Chad (figure 4.4).
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Figure 4.2 : ICN third decade of August 2015
Figure 4.3 : VCI third decade of August 2015
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Figure 4.4 : SNDVI third decade of August 2015
V. Hydrological situation
Heavy rains recorded in August, have been favorable
to the flows in the main river basins of the region.
The monitored hydrometric stations recorded a
significant increase in water flow volume during
this month. As for the local Niamey Niger River
water stage the peak occurred earlier than normal,
however, the discharges recorded in August were
globally below those of July. At Senegal River level,
a significant flow increase was recorded with peaks
reaching or even over passing the warning levels.
All water bodies are filled to capacity and only
very few reservoirs have not started to discharge
yet. The comparison of the current situation to the
(1981-2010) flow amount normal and to the dams’
filling level of 2014 indicates a globally normal to
surplus situation (figure 5.1).
In September, considering the perspectives of a
decrease in rainfall, a flow decrease with respect
to August situation is expected. However, it is
important to continue to closely monitor the river
stage as flood risks persist, particularly in the
Senegal River basin.
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Figure 5.1 : Synthesis of the situation of water courses and dams in late August 2015 : Stations of Koulikoro
(1), Niamey (2), Kainji (3), Makurdi (4), Lokoja (5) ; Ndjamena TP (6), Bagara (7), Oualia (8), Gourbassi (9), Kidira
(10), Bakel (11), Tiassalé (12), Bétérou (13) et Zio (14) ; dams of Seytenga (B1), Ziga (B2), Bagré (B3) and
Moussodougou (B4).
Niger River basin
In the Upper Niger River at Koulikoro station, the flows of
August 2015, although above those of last year, remained
below the hydrological normal (1981-2010) and the
average of the previous ten years (figure 5.2a). The filling
of Sélingue dam’s reservoir started in mid-July and is still
in progress. In the Middle Niger, the heavy precipitations of
the last two dekads of July led to important flows increase
at the Burkina tributaries ( Sirba, Gorouol and Dargol)
and consequently at Niamey level where the recorded
discharge had reached 2127m3/s on August 5 (figure
5.2b).
5.2 A
his discharge corresponded to a mark of 580 cm above
the 540 cm warning mark before the recent rising of the
river’s protection dike. It over passed the 2112 m3/s
discharge of 2010 that caused important floods and led
to heavy damage at the right bank of the river in Niamey.
After the peak of August 5, the discharges experienced a
steady decrease and were down to 947 m3/s on August
21. A slight rise was observed since that date. From June
1st to August 31st the amount of water flow volume was
5,01 billion m3.
Figure 5.2 (A&B) Comparative hydrograph of Niger River in
Koulikro and in Niamey
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Senegal River basin
During the month of August, rainfall improved significantly in the Senegal River Basin. At the upper
basin, the discharges of Bafing at Bafing Makana station rose and reached 1612 m3/s on August 23,
a decreasing trend started afterward with some fluctuations. At the Oualia station on the Bakoye and
Gourbassi on Falémé, discharge increase that began in July, continued in August. The flow rates of the
two stations remained above those of 2013, 2014 as well as the median of the last 10 years until the end
of August, despite some saw-tooth developments. At the
Bakel station, the water level continued to rise to reach
3622 m3/s on September 3.
The discharges have remained higher than those of last
year and the average of the previous ten years. It was the
same at the Matam station. The situation in the Senegal
River Basin, especially in Bakel, was expected to evolve
to higher discharges in September, resulting to a risk of
flooding in the basin. At the Manantali reservoir, the rise
in water levels began on July 24, 2015 and continued to
exceed the IGN mark of 200 m at the end of the month
(figure5.3).
Situation of dams in Burkina Faso
Figure 5.3 : Comparative hydrograph of Senegal River in
Bakel
The important rainfall recorded over most gauge stations in Burkina Faso led to a fairly significant increase
of water bodies’ levels that were all in a filling trend. Most dams discharged on 31st August 2015. The
filling rates in late August were significantly higher than those of the previous year in almost all strategic
dams in this country. However, the filling rate of the dams of Moussoudougou and especially that of
Toussiana in the Comoé Basin remained very low in late August. It was the same for Kompienga dam
which, although higher than last year at the same period, the filling rate also remained low.
 Director of Publication :
BOUAFOU Kouamé Guy Marcel
 Editor in Chief :
Maty BA DIAO
 Deputy-Editor in Chief :
Issa GARBA
 Contributions :
Abdallah SAMBA, Agro-meteorologist
Dr Abdou ALI, Hydrologue
Dr Alkhalil ADOUM, Scientist Regional FEWS NET
Issoufou MAIGARY, hydrologist
Dr Idrissa MAIGA, entomologist
Dr Alhassane AGALI, Agronomist
Dr Seydou TRAORE, Agro-meteorologist
Issa GARBA, Pastoralist
Mme Lucie, climatologist
Hamatan MOHAMED, hydrologist
Bernard Minoungou, hydrologist
 Translater :
YAPI Yapo Jacques
 Layout: :
Abdoul Aziz MAINASSARA
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