Niger-HYPE

The Niger-HYPE is a hydrological model of the Niger River basin in West Africa.

The Niger River Basin

The Niger River is West Africa´s largest river, with about 100 million inhabitants within the catchment area. Many of these live in poverty. The area covers nine countries spanning an enormous variety in climate and geography (Figure 1).

The river is an important natural resource, often key for livelihoods, especially in Mali and Niger. In addition, the region has been designated as a particularly sensitive area in terms of climate change impacts.

Figure 1. Mean annual precipitation in the Niger River basin.
Figure 1. Mean annual precipitation in the Niger River basin (1979-2009, based on WFDEI).
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The Niger-HYPE model

The development of Niger-HYPE is funded by the SIDA Project “Building resilience to floods and droughts in the Niger River basin - hydrological predictions for sustainable water user and climate change adaption”, and the EU FP7 project “IMPACT2C”.

The research aim of the projects is to explore the possibility of representing and quantifying the dominant hydrological processes in the basin with the HYPE model, and to assess potential effects of climatic changes on the hydrology of the basin.

The methodology is based on a participatory co-learning approach aiming to maximize the use of both Swedish and West African experts’ knowledge to collaboratively create an adapted modelling tool of the basin. This involves using open code and open data, and sharing model development and analysis (Figure 2).

We believe the participatory approach will strengthen the local ownership and enable future refinements and model application without necessarily involving external actors. This can facilitate sustainable management and adaptation of the water resources in the basin by the people living there.

Figure 2. Examples of collaborative research activities
Figure 2. Examples of collaborative research activities and end-user interactions in Mali, Niger and Sweden.
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One example of a fruitful effect of the participatory approach concerns the simulation of the Inland Niger Delta in Mali. The original HYPE code was adapted to the local hydrological conditions by adding a routine for simulating floodplain dynamics and temporal lakes, which improved model performance substantially (Figure 3).

This adaptation was only possible by combining the process understanding of the West African scientists with the technical expertise of the Swedish scientists.

Figure 3. Daily river discharge at the Tossaye station.
Figure 3. Daily river discharge at the Tossaye station, downstream of the Inland Niger Delta, simulated with (green) and without (red) the floodplain dynamics routine, relative to observations (black).
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The Niger-HYPE model is currently used to study the potential effects of climatic changes on floods, droughts and other water-related phenomena; and to connect this to adaptation strategies in West Africa (Figure 4).

We also explore the possibility of using the tool for water resources management, education, and operational hydrological warning services together with key institutions in the region.

FIgure 4 Results from Niger-HYPE
Figure 4. Lakes, reservoirs, river network and 56 river flow stations used in the calibration and validation of the Niger-HYPE 2.0 model. (a,b) Model performance during 1979-2009 relative to observations at the Koulikoro and Onitsha stations. NSE refers to daily Nash-Sutcliffe Efficiency and RE refers to cumulative relative error in water volume. (c,d) Projected changes in mean monthly river flow due to climate change. The lines represent the median and the shades represent the range of three projections from the bias-corrected MENA-CORDEX collection for the RCP4.5 (MB4) and RCP8.5 (MB8) emission scenarios, respectively. (e) Projected changes in duration (Days<Prc10) and intensity (Mean<Prc10) of agricultural water stress (based on the daily soil moisture fraction of the field capacity in the root zone).
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