A new piano key weir (PKW) dam has been commissioned by the Department of Water and Sanitation (DWS) at the Hazelmere dam, in the Mdloti river in KwaZulu-Natal.

The commissioning of the dam followed the successful raising of the dam wall by 7 m, from 86 m to 93 m, which included the construction and retrofitting of a PKW onto an existing dam spillway structure and the installation of 83 rock anchors, as well as foundation grouting and other minor related works.

The project aims to improve water supply to eThekwini metropolitan, iLembe and Kwa-Dakuza municipalities in the North Coast and to increase capacity of storage and augment the water supply to areas such as Verulam, Groutville, Blythedale and Ballito.

“The Hazelmere dam can now be measured against world class standards owing to the type of spillway selection, technology and innovation used in implementing the project,” said Water and Sanitation Minister Pemmy Majodina.

“Some of the employed technologies undertaken to upgrade the dam wall included the world’s highest PKW. The world’s largest anchors were installed to improve stability of the concrete gravity dam wall structure, and the largest capacity post-tensioning stressing jacks were deployed during construction,” she explained.

The dam has an uncontrolled PKW spillway to ensure that the dam wall withstands extreme concentration of floods of between six and eight hours for the dam catchment area.

Other technologies included the use of innovative data management software for real-time monitoring of anchor performance and 3D digital crack meters.

According to Majodina, the upgrading of the wall assisted with the creation of employment opportunities for 187 locals, of which 16 were women and 53 were youth, while 11 small, medium-sized and microenterprises were appointed, two of which were women-owned.

In addition, 14 engineers were successfully trained during the project, with some subsequently obtaining professional registration, marking a significant achievement in capacity building.

“The DWS upgraded the Hazelmere dam wall to meet the needs of the increasing population in the North Coast, as it is our role to ensure bulk water supply,” Majodina continued, urging municipalities to “roll up their sleeves” to ensure that water is directed to households and emphasising the important role that municipalities have to play in order to ensure the reticulation of water to households.

“The North Coast of KwaZulu-Natal has experienced rapid growth in recent years, especially in the housing sector which resulted in an increased demand for potable water. The raising of the dam wall will address water challenges in some parts of the three municipalities.”