Assessing the Threat of Erosion to Nature-Based Interventions for Stormwater Management and Flood Control in the Greater Accra Metropolitan Area, Ghana
			
	
 
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				Technische Universität München, Freising, Germany
				 
			 
										
				
				
		
		 
			
			
		
		
		
		
		
			
			 
			Data publikacji: 01-01-2018
			 
		 			
		 
	
							
					    		
    			 
    			
    				    					Autor do korespondencji
    					    				    				
    					Joel Bernard Kofi Asiedu   
    					Technische Universität München, Emil-Ramann Str 6, D-85354 Weihenstephan-Freising, D-85354 Freising, Germany
    				
 
    			
				 
    			 
    		 		
			
							 
		
	 
		
 
 
J. Ecol. Eng. 2018; 19(1):1-13
		
 
 
SŁOWA KLUCZOWE
DZIEDZINY
STRESZCZENIE
Perennial floodinghas become a major feature in urban areas in developing economies generating research interest towards finding alternative approaches to stormwater management which could complement the existing systems and help address the challenge of flooding. One of such alternative approaches is nature-based stormwater management and flood control, the implementation of which could be affected by soil erosion. This paper, as part of a wider research, was developed to determine the extent of the threat of soil erosion to stormwater management in an urban area on the example of Greater Accra Metropolitan Area, Accra Ghana as the focus of the research. Landsat 8 images (2014) were used in the research to prepare the Landcover maps. Daily rainfall data from 6 raingauge stations from 1972 to 2014 were utilized to prepare the rainfall erosivity factor maps, whereas DEM was used to prepare the slope and slope length (SL) factor maps. The land cover map with an overall accuracy of 73.6 and Kappa 0.7122 was combined with literature sources to prepare the vegetative cover factor map, and conservation practice factor map. A soil series map, prepared and updated with literature sources and data from the Harmonized World Soil Database on physical parameters, was used to calculate the soil erodibility factor (K factor) for each soil series. These were integrated into RUSLE model as 30 m raster maps to generate a soil loss map at tons/ha/yr. The results produced rainfall erosivity index values based on the modified Fournier index ranging between 0.058 and 23.197 which is classified as low. Low soil erodibility factor (K) ranging between 2.9×10–5 and 8.5×10–2 (t ha/MJ mm) indicated low susceptibility to erosion, SL factor value showing areas of low to almost flatrelief with a few isolated areas of moderate slope length were generated. A soil loss of 69,5918 tons/ha/yr classified the soils as having high potential soil loss. The results showed a very low soil loss threat of 0–5.1853 tons/Ha/yr for more than 90% of the study area. Targeted intervention for source areas with high potential soil loss will contain any threat of erosion and sediment yield to the implementation of an infiltration-based stormwater management and flood control system