Resilient Design Approaches: Elevating Communities and Saving Lives

Earlier this month, Andy Noble, Technical Executive - Hydropower and Tunnels, addressed the New Zealand Society on Large Dams and Australian National Committee on Large Dams (NZSOLD ANCOLD) 2019 Combined Conference.

Held in Auckland, New Zealand, this year’s event was centred around the theme of resilience.

 

Discussing ‘A resilient dam for a resilient community in East Africa - challenges in designing small hydropower for a wild river’, Andy presented the paper he co-wrote with Rob Kingsland, Technical Executive - Geotechnics.

 

The paper chronicles the technical challenges our team faced during the development of the Nyamwamba hydropower plant in Western Uganda.

 

According to Rob, this encapsulated several attributes that are quite common to most of the projects WSP is dealing with in that part of the world.

 

“We've been working on small hydropower in East Africa for many years,” said Rob. “I think one of the key challenges here was just matching appropriate technology to the setting.”

 

The paper gives readers a glimpse of the highs and lows of designing resilient dams that not only have to stand the test of time but also the test of nature.

 

The waters that feed the Nyamwamba River start as meltwater from the glaciers high up in the Rwenzori Mountains.

 

Prior to the project commencing, major flooding in 2013 caused realignments to the natural river course washing away a bridge, a wing of a hospital and claiming lives. For flooding, doesn’t just involve water. Those flood waters also carried debris and gigantic boulders it dislodged along the way.

 

He adds, “It’s quite a high-energy environment. Some of the sizes of the boulders, it's alarming to think how ferocious the water needed to be to ship some of them along. These flood events are pretty significant.”

 

Experiencing firsthand what was at stake only added fuel to the fire for Andy and Rob’s team to deliver superior outcomes.

 

Our role as lenders’ technical advisor (overlapping for two years as owner’s engineer as well) involved working with the owner/developer of the scheme to develop the design standards, perform a design review function and play a surveillance role.

 

That role saw the team visiting the site to ensure the evolution of the project was consistent with the design and in compliance with high standards for environmental and social aspects.

 

“It required us to visit on a regular basis and it was great,” adds Rob.

 

“I like to think of it as grassroots engineering.

 

“We’re working in these local communities and being challenged to rethink the way we apply basic engineering and clearly communicate the way we do things to stakeholders that aren't necessarily familiar with some of the terminology or the technology that we’re talking about.”

 

Three months after commissioning the scheme in June 2018, another major flood event occurred in the area. The project components suffered no structural damage and the hydraulic performance of the weir satisfactorily met the design assumptions.

 

Rob is very proud of the positive impact WSP’s role has had on the community including employment opportunities, generators for a local hospital and raising the electrification rates within Uganda where only 20% of households have electricity access.

 

“It's quite rewarding and feels good to be a part of that,” he concludes.

 

To find out more about Andy and Rob’s work, download their conference paper here.

 

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Download Paper Here