Maiden Erlegh Nature Reserve

Building the Silt Entrapment Pond

Water entering the lake generally comes from the run off from roads around Earley and enters through the inlet at the Beech Lane end of the lake. This runoff contains a lot of silt and grit which is washed off the roads. Every 20 years or so the lake needs to be dredged as the silt deposits itself in the lake making it shallower and shallower. Currently it will cost about quarter of a million pounds to dredge properly so a plan was devised to prevent this from ever happening again.

The idea was to create a Silt Entrapment Pond, this is a pond surrounded by 3 dams which channel the water causing the flow of water entering the lake to slow down and deposit the silt in the newly created pond. In the future it will be possible to hire a digger for a day which can then dredge just this pond, instead of the whole lake.

(Click photo to see it full size, followed by the "back" button)
This is how the inlet looked before the work started
Preparing the Gabian Baskets which will be used to create the 3 dams
The initial digging work starts to prepare the banks and dredge the inlet
Putting the baskets into place, which involves creating a level base, positioning the baskets then securing them in place
Next comes the back breaking job of filling the baskets with 40 tonnes of stones and wiring the cages shut
Next the actual silt entrapment pond needs to be dug out
Now wooden stakes are hammered into the pond to give it some strength and for cosmetic reasons