Hydrology plays an important role in shaping the dynamics of malaria transmission in Africa. The hydrologic processes that lead to the formation of water pools near African villages represent a key link between variability in the natural environment and the dynamics of malaria transmission. The long-term goal of the proposed research is to develop credible computational tools that can be used to (1) design intervention technologies based on environmental management of the local hydrology; as well as to (2) predict the impact of climate variability on the hydrology of water pools and the associated malaria transmission. The proposed project represents the first steps toward this goal. In the course of the proposed research, two graduate students will be introduced to this important field of research. This project will contribute to the ongoing international research project on African Monsoon Multidisciplinary Analysis (AMMA).
The objective of the proposed project is to improve our understanding of the factors that define the hydrology of water pools in Africa. The HYDRology, Entomology and, MAlaria Transmission Simulator (HYDREMATS) of Bomblies et al (2008) will be developed further to incorporate interaction between local aquifers and formation of water pools and to describe the impact of changes in regional climate forcing and in land use. We shall determine how local environmental conditions lead to the formation of these natural water bodies and hence provide habitats that are suitable for sub-adult mosquitoes; and we shall attempt to predict the response of these pools to climate variability and climate change. A field site in Niger will serve as the focus of this activity. Special attention will be devoted to link field measurements and model development activities, e.g. villages are selected to represent a range of variation of water table levels. Several important questions will be addressed: What is the role of local environmental conditions (rainfall, soil, topography, and vegetation) and microclimatic conditions (defined in terms of radiation, temperature, wind and humidity) in dictating the dynamics of the water pools that serve as habitat for mosquito populations? What is the relative role of local hydrologic conditions, such as location within a watershed and depth to the groundwater table, in shaping the water pools? Can we predict the response of these water pools to seasonal, inter-annual, and longer term climate variability in Africa? What is the impact of land use change on the spatial coverage and persistence of these water pools? A specific set of hypotheses will be studied with emphasis on the followings: (i) A significant fraction of the variation in mosquito abundance between villages can be explained by variation in the location of groundwater table relative to the surface; (ii) Land use change in the Sahel and the associated degradation of vegetation and soil will result in increasing the fractional spatial coverage and the persistence of mosquito breeding habitats; and (iii) Adult mosquito abundance can be predicted using satellite observations of rainfall over the Sahel. The predictions of this study will be subjected to a systematic analysis of the uncertainty that may arise from model assumptions and/or from prescribed range of model forcing.
