Cycle 2 (2012 Deadline)
Impact of climate change on freshwater availability for Senegal: modeling future changes in
hydroclimatology of the Lake of Guiers
PI: Mouhamadou Sylla (Laboratoire de Physique de l'Atmosphere et de l'Ocean)
U.S. Partner: Jeremy Pal (Loyola Marymount University)
Project Dates: August 2013 to December 2015
|The project team visits local farming communities near the Lake of Guiers (Photo: Dr. Sylla).|
This project aims to study climate change effects on the Lake of Guiers, the main freshwater reservoir for Senegal. The water is mostly used for irrigated cropping in the basin and domestic use in Dakar. It is unknown how its hydroclimatology might evolve in the future, but changes in surface runoff over the basin and in the amount of water in the lake could produce significant disturbances for end-users.
The researcher in this project will analyze past and present-day climate and water resources, elaborate climate change projections over the lake basin, and produce future scenarios of water resources for the lake. A series of three workshops will be organized at the end of each task to engage, inform, and exchange information with the end-users
As for development impacts, this project will generate a unique dataset in the field of climate change modeling over Senegal. This dataset can serve as input for more high-impact studies beyond the activities included in the project, for example in the fields of health and ecosystems. Policy makers could also use the datasets generated to develop adaptation and mitigation strategies. Thanks to the project's expected results, Senegal’s government will for the first time possess robust short-term (2021-2050) and long-term (2071-2100) projections of the amounts of freshwater available in the lake and thus potable water for domestic use in Dakar. In addition, production of future estimates of surface runoff in the lake basin is a great asset for agricultural policy makers, as these conditions can either depress or favor irrigated cropping. This study will raise awareness for an improved water resources management and stimulate the elaboration of more appropriate adaptation strategies to secure sustainable irrigated agriculture and potable water distribution in the future.
Summary of Recent Activities
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Dr. Sylla and his project team have finalized their simulations and the work related to this project.
A final seminar was organized in the Lab with the different students/researchers who were taking part in the implementation of the project. They also carried out a last field visit to the Lake basin where they had exchanges with the users that turned out fruitful. With the help of the PEER grants, they have developed communication and adaptation strategies to cope with the projected water scarcity.
Some of the key achievements of this project include:
A Ph.D. and 2 MSc theses have been defended. Five papers have been published and a manuscript is in internal review pending submission.
Secondly, two courses have been introduced in the lab: Climate Modeling with practical (hands-on sessions) and West African Monsoon Dynamics. For the first one, the students after being lectured on the basics. They have learnt how to run a regional climate model, process and visualize the data. For the second course, after acquiring some basic knowledge, the students were trained to use observations, reanalysis and model output to characterize and plot key feature of the monsoon (i.e. Monsoon flow, African Easterly Jet, Tropical Easterly Jet, African Easterly Waves, Saharan Heat Low, and meridional temperature gradient ...).
The main aim of this project was to characterize the impact of anthropogenic climate change on water availability in Senegal with a focus over the lake of Guiers basin. This has been modeled and analyzed for the middle (2041–2060) and late twenty-first century (2080–2099). High-resolution multi-model ensemble based on regional climate and hydrological model experiments which considered two core Intergovernmental Panel on Climate Change (IPCC) Representative Concentration Pathways (RCP4.5 and RCP8.5) were undertaken. The results indicate that an elevated warming, leading to substantial increase of atmospheric water demand, is projected over the whole of Senegal. In the Lake basin, these increases in potential evapotranspiration (PE) range between 10 and 25 % in the near future and for RCP4.5 while for the far future and RCP8.5, they exceed 50 %. In addition, mean precipitation unveils contrasting changes with wetter (10 to 25 % more) conditions by the middle of the century and drier conditions (more than 50 %) during the late twenty-first century. Such changes cause more or less evapotranspiration and soil moisture respectively during the two future periods. Furthermore, surface runoff shows a tendency to increase in most areas (amid few locations including the Lake basin with substantial reduction) probably due to the intensification of precipitation events.
Finally, it is found that while semi-arid climates develop in the RCP4.5 scenario, generalized arid conditions prevail over the whole Senegal for RCP8.5. These conditions will lead to less available water and more crop water uptake. It is thus evident that these future climate conditions substantially threaten freshwater availability for Senegal and irrigated cropping over the Lake basin.
This study will raise awareness for an improved water resources management and stimulate the elaboration of more appropriate adaptation strategies to secure a sustainable irrigated agriculture and potable water distribution in the future. It is thus clear that the fate of water resources is directly tied to climate change, agriculture and food security. The results can thus be used by policy makers to develop adaptation and mitigation strategies. Climate change and its adverse impact on water resources and food security are a major concern for the Sahel in general and Senegal in particular. Their results provide a scientific basis for stakeholders and can help targeting investment in climate change adaptation. In addition, it has promoted teaching and learning in a broader context and has increased the participation of female students in geosciences research.
In conclusion, the Principal Investigator had the following recommendations:
- The government of Senegal should implement policies that will help in designing response options to cope with the challenges posed by the projected climate change for the country. These policies should aim at encouraging end users to diversify their activities at the basin by practicing fishery and livestock husbandry.
- They should also use the Lake water only during the dry season and sow during the rainy seasons to ensure that the cultivars are more resilient to hotter and drier conditions with a shorter growing season,
- Lastly, the government of Senegal should sensitize users and provide them with means to properly measure the amount of water they draw from the Lake and intensify the water transfer from the Senegalese river to the Lake.
With the PEER grant, the team has met and developed strong collaboration with the Direction de la Gestion et de la Planification des Resources en Eau (DGPRE), the ministry department that manages and plans for water resources in Senegal, the Senegalese Consumers Association, Department of Geography of the University Cheikh Anta Diop, The Organisation pour la Mise en Valeur du Fleuve Senegal, the Office of the Lake of Guiers and two communities practicing at the Lake of Guiers basin (Diokhor and Diaminar).
They are working together with these institutions to exchange information, carry out surveys and data collection.