ENVIRONMENTAL ENGINEERING
Gulley in 2017
Inside a section of the gulley in February 2019
An aerial view taken in September 2020, showing the extent of the erosion The gulley just as construction began in 2020
Innovative rehabilitation of a deep gulley Vergelegen Wines in Somerset West is very proud of its farm’s heritage and takes great care of the environment. Among other things, at its own cost, the company has cleared more than 2 000 hectares of alien vegetation to create a fynbos reserve. One of the most recent interventions entailed a major erosion control project. By Hans King, Pr Eng Client: Vergelegen Wines Project design and management: HansKingSRS Construction: Martin & East Year construction completed: 2021
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IMIESA May 2021
F
ollowing the 2013 storm season, the appearance of a small gulley on the Vergelegen Wines farm was cause for concern. From 2017, this gulley suddenly accelerated in size as the dispersive weathered Cape granite soils below were
exposed and eroded rapidly. Between 2017 and 2018, the gulley increased from 30 m to 400 m in length, and from 2 m to 6 m deep. Downstream from the gulley, an area of Lourens River fynbos was smothered by the sediment. Plans for rehabilitation using cascades of weirs and other measures were prepared in early 2018 and the lengthy environmental approval process was started. An attempt was made to have the gulley recognised as a disaster and shorten the approval process – but, because the damage began in 2013, this was not allowed. The approval process took nearly a year, while the gulley grew even longer and deeper.
