Monitoring Spit Development In Pomene, Southern Mozambique, Using Landsat Data
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E. A. Massuanganhe & W. Arnberg
Coastal dunes, estuary, mangrove, and sand beach outlining a spit characterize Pomene on the southern coast of Mozambique. The spit is of interest for tourists and susceptible to coastal processes. Thus, four Landsat TM/ETM+ images dated 1984, 1989, 2001 and 2007 were used to monitor the geomorphologic change as well as to find the pattern of spit development spatially and temporally. From each Landsat image we extracted land and water (outlining the spit) by grouping 30 spectral classes from unsupervised ISO DATA classification using red, nearinfrared (NIR) and short-wavelength infrared (SWIR) spectral bands. Geographic Information System (GIS) software was used to process and present the final maps. Cross-classification was carried out to show the spatial difference between the dates. The results show a growth of the spit towards NNW and erosion at the Indian Ocean side, suggesting a longshore drift process in this area. The spit is becoming narrow and threatening its shape in the short term. The longshore currents caused by prevailing SSE winds, and offshore winds, are the main causes of the spit development. Keywords: monitoring spit, coastal erosion, shoreline, southern Mozambique, coastal processes, estuary, Pomene. 1 Introduction Located in Southern Mozambique, Pomene is known for its long beaches attracting tourists to the area bringing income to the country and to the people living nearby. Like many places in the Mozambican coastal zone, Pomene faces
monitoring spit, coastal erosion, shoreline, southern Mozambique, coastal processes, estuary, Pomene.