Erosion | Taking erosion seriously
Angus Hughson from the Big Ditch in Australia explains why erosion control really matters for earth dam safety
Right: Erosion control Whittlesea, Victoria in Australia. The foundation of smart dam management lies in taking erosion seriously
Below: Erosion in Newcastle, New South Wales
If you want to build an earth dam in Australia that actually holds up for years, you must tackle erosion before trouble even starts. Sure, legal requirements make erosion protection mandatory for dam owners and contractors – everyone’s got to meet the regulations. But on a practical level, erosion control is what keeps a dam working, your water reserves reliable, and headaches to a minimum. Erosion can sneak up quickly. Soil gets scraped away, gullies pop up after just one heavy downpour, and sediment spreads further than you think. Any of these problems can weaken a dam’s structure, blow out your annual maintenance budget, and even leave you with fouled-up water downstream. Across Australia, where weather can swing from bone dry
to wild storms in a matter of weeks, getting erosion management right is not optional; it’s simply part of doing business as a dam builder.
How Big Ditch tackles erosion Building farm dams that last relies on hard-won
experience and solid science. Projects can’t just follow a formula; every job has to be adapted to what’s happening on the ground. From the first plan on paper all the way through planting native species, risks have to be identified and then adjusted accordingly. The focus is on smart site grading, top-notch installation of HDPE liners, and water flow controls that match actual weather patterns and soil conditions.
Recognising erosion in action There isn’t just one type of erosion to watch for; it can
take many forms. For example, basic surface erosion strips away fine soil from dam faces, especially once grass cover thins in drought. That alone weakens the earthwork, and it’s nearly invisible at first. All you need is a strong rainstorm and suddenly rills and gullies carve through embankments, spillways, or dam walls – these channels grow especially fast if runoff isn’t properly controlled. Internal erosion, sometimes called piping, is the one you never want to see. It starts beneath the surface, where water finds hidden paths through imperfectly compacted soil. If those channels aren’t blocked or filtered, you’re looking at a real risk of the structure collapsing without warning.
In the field this means when you spot runoff carrying mud, rapid loss of water, or barren stretches where nothing grows, you know erosion control hasn’t worked as it should.
16 | November 2025 |
www.waterpowermagazine.com
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