Key findings from the Accounts for Strategic Water Source Areas, 1990 to 2020

Strategic Water Source Areas (SWSAs) are natural source areas for water that supply disproportionately large volumes of water per unit area and that are considered of strategic significance for water security from a national planning perspective, either for surface water or groundwater or both. They contribute significantly to the overall surface and ground water supply of the country. There are 22 SWSAs for surface water, which make up 10% of the total land area of South Africa, Lesotho and Eswatini and provide 50% of the combined mean annual run-off of these three countries.

The Accounts for Strategic Water Source Areas, 1990 to 2020 focus on accounts for land cover and protected areas within SWSAs for surface water. Seven of the 22 SWSAs are transboundary, and for these SWSAs the accounts focus only on the portion that falls within South Africa. The accounts were compiled for the period 1990 to 2020, which was divided into three accounting periods: 1990 to 2014, 2014 to 2018, and 2018 to 2020. These accounting periods were based on the availability of time series land cover data for the years 1990, 2014, 2018 and 2020.

Some of the key findings across all 22 SWSAs are summarised below.

SWSAs are located across the country stretching over several biomes, provinces and Water Management Areas. In total, they cover 10 020 720 ha or 8,2% of South Africa’s mainland. SWSAs vary greatly in size, with Southern Drakensberg SWSA having the largest extent of 2 013 693 ha (of which 1 842 150 ha falls within South Africa) and Table Mountain SWSA having the smallest extent of 47 241 ha.

The estimated total population per SWSA in 2011 ranged from 2 643 in Waterberg SWSA to 1 324 309 in Southern Drakensberg SWSA, with a mean of 336 470 across all SWSAs. The estimated total population for all SWSAs combined was 7 402 337, which was 14,3% of South Africa’s total population.

Population density in 2011 ranged from approximately 2,6 people per km² in Waterberg SWSA to approximately 1 550,8 people per km² in Table Mountain SWSA, with a mean population density of approximately 140,1 people per km² across all SWSAs. This compares to a population density of 42,2 people per km² for South Africa as a whole.

Key findings from the land accounts for SWSAs

Land accounts for SWSAs track changes in the extent and composition of main land cover classes (Tier 2) within SWSAs. Key findings are drawn from Section 3.2 of the discussion document D0401.3.

1.     In 2020, 68,7% (6 888 660 ha) of the total area of all SWSAs remained natural or semi-natural, compared with 70,6% in 1990. This means there was a net decrease of 181 141 ha in natural or semi-natural land cover in SWSAs over the 30 years from 1990 to 2020.

2.     In 2020, the six intensively modified land cover classes (commercial field crops, subsistence crops, orchards and vines, timber plantations, urban and mines) made up 28,8% (2 885 994 ha) of the total area of all SWSAs. This was a higher proportion than for South Africa’s mainland as a whole, in which intensively modified land cover made up 15,7% in 1990 and 16,2% in 2020.

3.     The proportion of timber plantations was much larger in SWSAs than in South Africa’s mainland as a whole in both 1990 and 2020. In 2020, timber plantations made up 13,9% (1 391 601 ha) of the total area of SWSAs compared with 1,7% of the total area of South Africa’s mainland. Among the intensively modified land cover classes, timber plantations also had the largest net increase in absolute terms between 1990 and 2020 in all SWSAs combined with an increase of 71 847 ha. SWSAs with the highest proportion of timber plantations in 2020 were Upper Usutu (40,1%), Mpumalanga Drakensberg (39,4%) and Mbabane Hills (22,0%).

4.     Among the intensively modified land cover classes, the largest net percentage increase between 1990 and 2020 in all SWSAs combined was a 51,9% increase in mines, from 3 444 ha in 1990 to 5 233 ha in 2020. SWSAs with the largest extent of mines in 2020 were Upper Vaal (1 216 ha), Northern Drakensberg (1 027 ha) and Mpumalanga Drakensberg (948 ha).

5.     Commercial field crops made up 6,3% (633 212 ha) of land cover across all SWSAs in 2020. SWSAs with the largest extent of commercial field crops in 2020 were Southern Drakensberg (154 382 ha), Enkangala Grassland (52 394 ha) and Boland (52 328 ha). SWSAs with the highest proportion of commercial field crops in 2020 were Upper Vaal (28,4%), Maloti Drakensberg (22,1%) and Langeberg (16,6%).

6.     Subsistence crops made up 2,5% (248 893 ha) of land cover across all SWSAs in 2020. SWSAs with the highest proportion of subsistence crops in 2020 were Eastern Cape Drakensberg (7,3%), Mfolozi Drakensberg (5,7%) and Southern Drakensberg (3,7%).

7.     Orchards and vines made up 1,5% (146 726 ha) of land cover across all SWSAs in 2020. SWSAs with the largest extent of orchards and vines in 2020 were Boland (66 302 ha), Groot Winterhoek (19 998 ha) and Mpumalanga Drakensberg (19 704 ha). SWSAs with the highest proportion of orchards and vines in 2020 were Boland (10,9%), Soutpansberg (6,8%) and Wolkberg (6,6%).

8.     Urban areas made up 4,6% (460 329 ha) of land cover across all SWSAs in 2020. SWSAs with the largest extent of urban areas in 2020 were Southern Drakensberg (123 349 ha), Eastern Cape Drakensberg (79 084 ha) and Soutpansberg (36 968 ha). SWSAs with the highest proportion of urban areas in 2020 were Table Mountain (39,8%), Soutpansberg (15,8%) and Amathole (7,8%).

Key findings from the accounts for protected areas in SWSAs

Accounts for protected areas in SWSAs track changes in the size and composition of the protected area estate within SWSAs. Key findings are drawn from Section 3.3 of discussion document D0401.3.

1.     The size of the protected area estate in all SWSAs in 2020 was 1 896 732 ha or 18,9% of the total extent of SWSAs, compared with 1 393 914 ha or 13,9% in 1990. This represents an increase of 502 818 ha (36,1%).

2.     In comparison, the proportion of South Africa’s mainland protected was 6,3% in 1990 and 9,2% in 2020. This means that the proportion protected in SWSAs was more than double the proportion protected for South Africa as a whole in both 1990 and 2020.

3.     The protected area types that contributed most to the protected area estate in SWSAs in 2020 were Nature Reserves (39,6%), Mountain Catchment Areas (19,2%) and Forest Wilderness Areas (12,8%). Mountain Catchment Areas, Forest Wilderness Areas and Forest Nature Reserves play a notably larger role in protection of SWSAs than they do in protection of South Africa’s mainland as a whole. National Parks play a notably smaller role in protection of SWSAs than they do in protection of South Africa’s mainland as a whole.

4.     Protected area types with the greatest increases in extent in both absolute and percentage terms in all SWSAs combined between 1990 and 2020 were Nature Reserves with an increase of 233 268 ha (45,1%) and Protected Environments with an increase of 154 582 ha (1 332,3%).

5.     SWSAs with the highest proportion protected in 2020 were Swartberg (76,5%), Kouga (72,3%) and Groot Winterhoek (63,5%). These three SWSAs were also among the five SWSAs with the highest proportion of natural or semi-natural land cover in 2020.

6.     SWSAs with the lowest proportion protected in 2020 were Eastern Cape Drakensberg (1,1%), Amathole (3,2%) and Mfolozi Headwaters (6,8%).

7.     SWSAs that had the greatest absolute increase in extent protected (all protected area types combined) between 1990 and 2020 were Southern Drakensberg (63 835 ha), Mpumalanga Drakensberg (55 557 ha) and Enkangala Grassland (53 686 ha). SWSAs that had the greatest percentage increase in protection between 1990 and 2020 were Soutpansberg (2 369,7%), Waterberg (1 322,2%) and Upper Usutu (1 265,5%).