Cover It Up. Stop The Mud. Save Our Gulf.
Every time exposed soil washes off a construction site, our beaches, marine life and waterways suffer.
This mud ends up in the ocean.
Sediment pollution is not abstract. Bare ground on a building site becomes the silt smothering our estuaries, beaches and marine life.
In simple terms
Bare soil washes away
Any exposed earth, no matter how far inland, gets carried into streams and on into the ocean every time it rains.
Controls aren't strong enough
Silt fences and ponds are often built too small to handle real stormwater volumes.
Stormwater flows through work sites
Clean water from uphill areas is allowed to run straight across exposed soil, making erosion far worse.
No limits on exposure
There are no rules about how long soil can be left bare on construction sites.
No measurement
No one is actually measuring how much sediment leaves a site.
Low awareness
Most people don't understand how destructive sediment is to marine life.
Recognised media coverage.
Source: Seasick. Saving the Hauraki Gulf. Episode 4: Pollution. Stuff.co.nz
82%
Around 82 per cent of sediment entering the Hauraki Gulf comes from small sites.
Sources: Our Auckland, “Taking a strategic approach to managing sediment” (11 December 2024) · Newsroom, on reviving the Hauraki Gulf (10 December 2025)
Sediment fences alone are often overwhelmed when the storm arrives.
Catch the sediment after it moves
- Catch sediment after it moves
- Sediment fences alone
- Often overwhelmed during storms
Prevent the erosion at source
- Prevent erosion at source
- Stabilise exposed soil early
- Divert water before runoff occurs
Don't just try to catch sediment. Preventing erosion solves the problem before it starts.
In simple terms
-
Cover all unworked soil.
-
Strict rules on bare soil. Set hard time limits for how long soil can be left exposed.
-
Build proper controls. Make developers engineer sediment ponds and barriers to match real stormwater volumes.
-
Independent monitoring. Require real-time water-quality testing, with results sent to both the developer and council.
-
Keep clean water out. Ban upslope stormwater from entering any active earthworks area.
Always Cover Exposed Soils
Simple, practical steps every site can follow to keep soil on site and mud out of the water.
Cover It Up
Here are some suggestions.
Talk to your erosion and sediment control professional for more ideas.
Rocks 
Hay 
Mulch 
Geotextile fabrics
Divert Surface Water Away From Exposed Soils
Silt Fencing
If there is going to be exposed soil on the site, construct a silt fence as per Council requirements.
Every Site Counts
The small jobs add up to a big impact!
Good Site vs Bad Site
Learn to recognise the practices that protect our waterways, and the ones that pollute them.
Good practice
Bad practice
Help protect local waterways and create change.
See sediment pollution?
For builders and developers
- Ask how sediment is being controlled
- Ensure exposed soil is covered before rain
- Request proper erosion prevention methods
Cover exposed soil before rain.
Protect the Gulf. Easy to understand, easy to do, and it keeps the mud out of the water for good.