Geospatial information for sustainable food systems

A rapid geospatial analysis of the flood impacts on crops in KwaZulu Natal and Eastern Cape Provinces of South Africa in 2022

Year published: 15/08/2022

South Africa is the southern most country on the African continent with the 121 309 ha of land area and highly dependent on agriculture sector (79 percent of agricultural land area) for food, income, and employment. Natural disasters like drought, floods, storms, cyclones etc. causes significant socio-economic damages and losses, as well as negatively impacting the agricultural sector.

From 11–13 April 2022, heavy rainfall caused severe flooding and landslides affecting the south and south-eastern part of South Africa. Particularly, in the Provinces of KwaZulu-Natal and Eastern Cape, authorities reported loss of lives, infrastructure damages and inundated cropland. Disaster Charter 755 was activated for South Africa. From 19–20 April, moderate rainfall waa forecast over north-eastern South Africa, while no heavy rainfall was expected over the already affected Provinces.

In this context, the Food and Agriculture Organization of the United Nations (FAO) Geospatial Unit of the Land and Water Division (NSL) with support from SFS REOSA conducted a rapid geospatial assessment on crops and the exposure of rural people during the period 10–20 April 2022. This assessment provides information at the district, local municipalities and ward levels in the area of interest (AOI).

This analysis combines Sentinel 1 (S1) Synthetic Aperture Radar (SAR) and Sentinel 2 (S2) imagery (both at a 10 m spatial resolution) with Planet imagery (5 m spatial resolution) and 2020 population data from Worldpop (100 m spatial resolution) to determine: (1) flood extent; (2) cropland area; (3) flooded crop area; and (4) exposure of population to flooded cropland. The results are provided in the form of maps by administrative units and tabular with descriptive statistics for the aforementioned indicators. With recent advances in geospatial and information technologies and updated land cover maps, crop specific information adapted to national conditions with tailored field campaigns have the potential to better support response programmes and agricultural development in the future.

The key findings from this rapid assessment are that for Area of Interest (AOI): 1) total flooded area in the Province of Eastern Cape is 373 868 ha and in the Province of KwaZulu-Natal is 137 601 ha; 2) total cropland area estimated in Area of Interest is 1 386 941 ha; 3) overall inundated cropland is 51 601 ha (4 percent of the total land in AOI); and 4) the most affected districts in respect to people exposure to floods are Cacadu (54 616).