Pigeon Valley: KZN floods damage

In this article series, the riches of Pigeon Valley Nature Reserve are explained by Crispin Hemson, Glenwood resident and chair of the Friends of Pigeon Valley. 

While part of Pigeon Valley was hard hit by the floods, the majority of the reserve was almost completely unaffected. Understanding why is important and can inform us on the way we need to respond to climate change.

A recent project that aimed to direct excess water flow through piping under the main track failed, leaving Pigeon Valley damaged by the floods. The excess water poured out of the chamber at the top of the project, scouring away the soil on the sides of the concrete. Eventually, the concrete paving collapsed. The retention pond is now completely full of sand and huge holes have appeared in the main track below and it can no longer be used.

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The reason there is a significant problem with water flow in Pigeon Valley is because of the hardening of surfaces upstream. Firstly, the Berea ridge is made up of historic sand dunes that can absorb great quantities of water. However, for decades people have been allowed to pave over the entire property in some cases. That imposes a burden on the properties and infrastructure downstream, which are subject to huge amounts of storm water. Secondly, rainfall on April 11 was very likely to have been the highest 24-hour level on record, as several Durban stations reported their highest figures. My estimate is between 300 and 350mm.

How plants play a role

Despite these stresses, there has been remarkably little erosion in the rest of Pigeon Valley, demonstrating the capacity of the soil to absorb water. There is inevitably heavy runoff when the soil is saturated, however, the root systems of trees and plants held the soil successfully. Looking at the videos taken from helicopters last week, I was struck by how irresponsible so much building on the coastal strip and other steep areas has been. People have pushed onto the edges of steep slopes. Trees and undergrowth have been replaced by lawn or concrete, so the overwhelming runoff has dug into the slopes.

For decades, development has consisted of attempting to overpower nature. We drain marshes and pave them over for huge factories. We straighten rivers and speed up their flow. We erect barriers against the sea. In the end, when you see water reoccupying the former marshes of South Durban, you realise this is a battle we may well lose.

ALSO READ: Exploring Pigeon Valley: The Stormwater Project

To resolve these issues, we need processes of participation. We need to engage, for example, with people in informal settlements on how to protect the land they are on and themselves. Schools should help learners understand the local challenges around water and ways of handling them well. The way ahead needs to be one that works with people at all levels to develop imaginative solutions. These solutions need to be based on how we work with nature and use its capacity for protection and rehabilitation.

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