GC44B-06
Modeling annual flooding in the Logone floodplain in Cameroon
Thursday, 17 December 2015: 17:15
3003 (Moscone West)
Alfonso Fernandez1, Mohammad Reza Najafi2, Michael T Durand3, Bryan G Mark1, Mark Moritz4, Apoorva Shastry3, Sarah Laborde4, Sui Chian Phang5, Ian Hamilton5, Xiao Ningchuan1 and Jeffrey C Neal6, (1)Ohio State University, Geography, Columbus, OH, United States, (2)University of Victoria, Victoria, BC, Canada, (3)Ohio St Univ-Earth Sciences, Columbus, OH, United States, (4)Ohio State University, Anthropology, Columbus, OH, United States, (5)Ohio State University, Evolution Ecology and Organismal Biology, Columbus, OH, United States, (6)University of Bristol, School of Geographical Sciences, Bristol, BS8, United Kingdom
Abstract:
The Logone floodplain (LFP), part of the Lake Chad Basin, is flooded annually by water from the Logone River and its branches during September and October. The inundated LFP is highly productive, providing support for fishing, pastoralism, and agriculture. In the last few decades, droughts, dam construction, manmade fishing canals (MFCs), and irrigation development have caused significant shifts in the LFP’s flooding regime. Recently, MFCs have proliferated as consequence of ecological and manmade changes in the LFP. Future impacts of these modifications may parallel projected, although still uncertain, regional hydroclimatic changes derived from global warming. In order to understand feedbacks between human actions and hydroclimate, we are developing an integrated model that links hydroclimate, hydraulics, and human dynamics such as fishermen and pastoralist behavior. Here we present one component of this research focused on simulating the annual flooding dynamics of the LFP using LISFLOOD-FP, a raster-based numerical model that includes sub-grid parameterization of MFCs. Our goal is to evaluate the model’s skill to simulate spatiotemporal features of the inundated LFP using a minimum amount of input data, such as discontinuous time series of river discharge and satellite-derived rainfall. Our simulations using three different spatial resolutions (1, 0.5, and 0.25-km grid-cell) suggest that the model is insensitive to pixel size, showing no significant differences between simulated volume, discharge, flooded area, and flood seasonality. Despite the model is able to simulate flow, with a Nash Sutcliff efficiency of 0.81, we find some significant spatial mismatch between observed and simulated inundation areas. In addition, results indicate that overbank flow provides more annual flood volume than rainfall. We discuss the impact of topographic and climatic input data on these results, as well as the potential to simulate the effects of MFCs on the local hydrology.
