Future runoff patterns were traditionally predicted using models based on decades of past rainfall data, but climate change is increasing the uncertainty of predictive models.
Managing water risks exacerbated by climate change makes predictive modelling vital, but at the same time more difficult – Africa’s response therefore needs to embrace flexible solutions through more sustainable engineering design.
The complexity of hydrological processes makes surface water modelling a challenging exercise at the best of times, according to SRK Consulting principal corporate consultant Dr Simon Lorentz.
“As the effects of climate are increasingly felt, we now also have to rethink how we make predictions,” says Lorentz.
“We used to be able to predict future rainfall patterns using models based on decades of past rainfall data, but now climate change is removing much of the certainty we had.”
Looking ahead, we now rely more on large-scale atmospheric models which describe how weather patterns form on a global scale and how they are likely to change in the future. Downscaling these into regional or local models, however, requires consideration of many variable factors like distance from the coast, altitudes, hillslope aspects and topography.
These global models can also be quite divergent, leading to different results. Predictions are therefore unlikely to be simple or precise, especially as their timeline lengthens.
“Southern Africa’s status as a mostly semi-arid region adds to the complexity of making predictions, as we have always experienced a relatively high level of variability between rainy and dry spells,” he says.
Read the full article in Why Africa
