Garden Route Dam Spillway and Embankment Crest Raising

Raising the Garden Route Dam spillway and embankment crest to improve water security and dam safety.

Client

George Local Municipality

Project date

Appointed in 2018

The Garden Route Dam is the primary source of drinking water for the town of George in the Western Cape. In 2018, Zutari was appointed by the George Local Municipality to raise the dam’s full supply level (FSL) and enhance its storage and discharge capacity. The project required a novel engineering solution to overcome unique spatial and hydraulic challenges.

The opportunity

Faced with increasing water demand and the need for improved drought resilience, the municipality sought to expand the dam’s capacity without developing a new site. The challenge was to design a spillway that could pass more flow within a limited footprint, while also raising the embankment to prevent overtopping.

What we did

Zutari developed and implemented an innovative solution:

Duckbill Spillway Design: A curved, non-linear spillway extended the overflow length from 25 m to 80 m, increasing discharge capacity and improving dam safety.

Structural Engineering: Constructed a reinforced concrete cantilever spillway wall, stabilised with upstream rockfill and rock anchors.

Dam Raising: Increased the FSL by 2.5 m and raised the embankment crest by 1.76 m using locally sourced earth fill.

Material Quantities: Used 1,780 m³ of concrete and placed 12,500 m³ of general fill, 2,500 m³ of rip-rap, 750 m³ of filter sand, and 2,050 m³ of topsoil.

Environmental Consideration: Focused on expanding an existing water resource to minimise environmental impact.

The duckbill spillway design increased the Garden Route Dam’s capacity by 25%, enhancing water security for George.

The outcome

The project increased the dam’s gross storage capacity by 2.5 million m³ to a total of 12.5 million m³. The enhanced spillway and raised embankment significantly improved the dam’s safety and drought resilience. The innovative design also demonstrated the benefits of expanding existing infrastructure to limit environmental disruption.

The Garden Route Dam upgrade showcases Zutari’s ability to deliver innovative, sustainable water infrastructure solutions. By combining advanced engineering with environmental sensitivity, the project ensures long-term water security for the George community.

“This additional storage will add much-needed drought resilience to the water-supply system. Expanding an existing water-supply resource is also preferable to the development of new sites, as it limits the extent of the environmental impact to an already impacted site.”

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Garden Route Dam Spillway and Embankment Crest Raising

Client

Project date

The opportunity

What we did

The outcome

Frank Denys

Related projects

The Docklands

Olifants River Bridge

144 Oxford Road

Securing water and wildlife: A sustainable future for Barrydale

Want to see more?

Want to see more?

Want to
see more?

Want to
see more?