B43F-0620
Analyzing surface water budgets for water-food security in seasonal wetlands of north-central Namibia
Thursday, 17 December 2015
Poster Hall (Moscone South)
Tetsuya Hiyama1, Hiroki Mizuochi2, Hironari Kanamori1, Yuichiro Fujioka3, Jack R. Kambatuku4, Ayumi Kotani5, Takeshi Ohta5 and Morio Iijima6, (1)Nagoya University, Institute for Space-Earth Environmental Research, Nagoya, Japan, (2)University of Tsukuba, Graduate School of Life and Environmental Sciences, Tsukuba, Japan, (3)Tohoku University, Frontier Research Institute for Interdisciplinary Sciences, Sendai, Japan, (4)University of Namibia, Faculty of Agriculture and Natural Resources, Ogongo, Namibia, (5)Nagoya University, Graduate School of Bioagricultural Sciences, Nagoya, Japan, (6)Kinki University, Faculty of Agriculture, Nara, Japan
Abstract:
This study aims to evaluate the water budgets in case of the introduction of rice-millet mixed-cropping systems (flood- and drought-adaptive cropping systems) to the Cuvelai system seasonal wetlands (CSSWs) in north-central Namibia. To achieve this goal, we at first investigated seasonal changes in surface water coverage by using satellite remote sensing data. For this investigation, we used MODIS and AMSR-E satellite remote sensing data. These data showed that at the beginning of the wet season, surface water appears from the southern (lower) part and then expands to the northern (higher) part of the CSSWs. We also assessed the effect of the introduction of rice-millet mixed-cropping systems on evapotranspiration in the CSSWs region. For this investigation, we used data obtained by the Bowen ratio-energy balance (BREB) method at an experimental field site established in September 2012 on the Ogongo campus, University of Namibia. This analysis showed the importance of water and vegetation conditions when introducing mixed-cropping to the region. Finally, in order to understand water sources of small wetlands in the CSSWs, stable isotopic ratio of water (precipitation, surface-, and subsurface-water) were analyzed. This analysis showed that shallow groundwater of small wetlands is very likely to be recharged from surface-water, source of which was local precipitation and was pooled in lowest part of small wetlands.
