Rainwater Silt Trap

The blue box you can see is a silt trap. It’s  a “Tim Experiment”.

Rainwater Silt Trap

Concrete silt traps are often used in conjunction with below ground tanks as it can be difficult to flush sediment from the tanks. We thought it would be worth including a silt trap to see what, if anything it would collect as “it is sediment that provides the food for bacteria and bacteria reduces the quality of stored rain water” (Michael Mobbs, Sustainable House).

The idea is that the collected rain water, after passing through the leaf eaters and first flush diverter, enters the trap through the low inlet. As the trap is wider than the down pipe the water slows down and any heavy sediment falls to the bottom, leaving the clean water to exit through the high outlet and into the tanks.

Have a look — it certainly does seem to collect a lot of silt!

Inside the Silt Trap