Cowling, R. (2022). “How catchment management could have prevented the Nelson Mandela Bay water crisis.” Nelson Mandela University, 17 May 2022.
Cowling summarizes studies he co-authored: degraded spekboom thicket soils infiltrate over a hundred times less than intact ones, and a 2010 modeling study estimated that restoring 225,000 hectares of degraded land in three catchments would add 11 million cubic meters a year of yield and 14 million of baseflow, with a benefit-cost ratio of 3.27. The wiki uses the per-hectare rate this implies and treats the figures as unverified until the 2010 study itself is cited.