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ATLAS

Atlas: mapping the inundation

Topographical maps of the Inner Niger Delta show the floodplain as if it were flooded at a maximum level, but the area actually inundated varies considerably between years. Only a high river discharge produces a high flood but also floods a more extensive area. Satellite images show that in the disaster year 1984, the flooded area during the peak flood was limited to a mere 7800 km2 against 22 000 km2 in the years before the Great Drought (1969-1993).

Satellite images were used to produce water maps of the Inner Niger Delta covering the full range of water levels; for all details see chapter 3 in the book The Niger, a lifeline.

Atlas: water maps

OPIDIN predicts the maximum flood level. Using the flooding model, given in The Niger, a lifeline, we can also indicate precisely the flood extent related to a certain flood level. The flood extent between 300 and 520 cm at the gauge of Akka is shown in 54 maps (27 for the northern and 27 for the southern half of the Inner Niger Delta).

All these water maps form together an Atlas, available as book, but also as pdf. The Atlas gives, beside the 27 two-page water maps, also eight separate detailed maps of the administrative delineations (region, cercle, commune) with all villages with more than 1000 inhabitants according to the National Census in 2007 and four maps of the southern Inner Niger Delta showing the impact of the flood level on the zoning of the vegetation.

The water maps given in the Atlas are used in the floodviewer.

OPIDIN: background information 

Zwarts, L. 2009. Predicting the annual peak flood level in the Inner Niger Delta. A&W-report 1254. Altenburg & Wymenga, ecological consultants, Feanwâlden  .

Preliminary version of OPIDIN

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Zwarts, L. 2009. Towards a further extension of the OPIDIN tool. A&W Report 1514. Altenburg & Wymenga, ecological consultants, Feanwâlden  .

Report about possible extensions and improvements of OPIDIN. It shows how the timing of deflooding, and thus the access of the grazing grounds, can be predicted months before.

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Zwarts, L. 2013. OPIDIN: predicting the flood in the Inner Niger Delta

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Zwarts, L. Hoekema, F.S. 2013. Atlas. Les plaines inondables du Delta intérieur du Niger. Altenburg & Wymenga, ecological consultants, Feanwâlden.

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Inner Niger Delta: background information

Wymenga, E., B. Kone, J. van der Kamp & L. I. Zwarts. 2002. Delta Intérieur du fleuve Niger. Mali-PIN publication 02-01. 240 p.

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Zwarts, L., Beukering van, P, Kone, B, Wymenga, E. 2005. The Niger, a lifeline. Effective water management in the Upper Niger Basin. 304 p.

Chapter 3 explains in detail how satellite images of the Inner Niger Delta were converted to water maps and how these maps were combined to construct a digital flooding model for incoming and receding water. The water maps for incoming water are used in OPIDIN.

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Chapter 3 from The Niger, a lifeline can be downloaded separately.

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Zwarts, L. 2010. Will the Inner Niger Delta shrivel up due to climate change and water use upstream? A&W Rapport 1537. 33 p. Altenburg & Wymenga, ecological consultants, Feanwâlden.

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Zwarts L. 2012. The impact of a lower river flow on the inundation, vegetation and land use in the Inner Niger Delta. A&W-rapport 1868. Altenburg & Wymenga, ecological consultants, Feanwâlden.

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Zwarts,L. & J.-L. Frerotte 2012. Water crisis in the Inner Niger Delta (Mali), Causes, consequences, solutions. A&W-report 1832. Altenburg & Wymenga, ecological consultants, Feanwâlden.

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Zwarts, L. & J. van der Kamp 2013. Does the Inner Niger Delta suffer from a reduced river flow in the dry season? A&W-report 1938. Altenburg & Wymenga, ecological consultants, Feanwâlden.

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METEO

The Famine Early Warning System website (FEWS) gives a lot of actual agro-climatic information for West Africa and Mali. The prediction about the harvest and possible famine is based on recent rainfall, but also takes into account political instability, etc.

An example showing the acute food insecurity, such as ascertained in May 2013.

The FEWS website gives nice maps of West Africa showing the estimated total rainfall combined for recent periods of 10 days.

An example showing the estimated total rainfall between 11 and 20 May 2013.

The FEWS website gives access to recent and historical rainfall data of West Africa.  The daily rainfall estimate (RFE) is given for the actual rainfall for the last six days and the forecasted rainfall for coming six days.The recent rainfall data are entered in OPIDIN to improve the prediction, see technical background.

An example showing the estimated total rainfall between 11 and 20 May 2013.

Link to the graphs showing the estimated rainfall per ten days, averaged for the different regio’s in Mali: Bamako, Gao, Kayes, Kidal, Koulikoro, Mopti, Segou, Sikasso and Tombouctou. The same data are also available for other African countries.

An example of the graphs for the regio’s Bamako and Gao, downloaded in May 2013.

Link to the graphs showing the estimated rainfall per ten days, averaged for the different regio’s in Guinea. The rainfall in the regios Faranah and Kankan during the first half of the raining season is the best predictor of the peak flow of the Niger River in September.

An example of the graphs for the regios Faranah and Kankan in eastern Guinea (thus the Upper Niger Basin), such as downloaded in May 2013.