Dam builders

In the last two weeks, there has been lots of activity at Model Boating Pond which is the largest work site of the whole project. There had been delays in this location due to problems with the temporary sheet pile dam. Now this issue has been resolved, by placing clay temporarily along the face of the temporary dam and the new permanent dam is under construction.

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Clay bund supporting the temporary sheet pile dam

The dam is being constructed by layering 200mm layers of clay on top of each other and then rolling them with a machine called a Sheeps Foot roller so that Reaches the correct compaction. Each layer is tested by a Shear Vein test which measures resistance of the clay and is an indicator of strength of the material. The clay we are using is of such good quality it is easily meeting the required strength.

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Sheeps Foot Roller compacting layers of clay

The clay to build the dam is being excavated from the borrow pit which is in the large work compound on the hillside next to the pond. These pits will then be filled in with silt excavated from the pond and returned to a similar gradient as before. The ground will then be seeded with a grass and wildflower mix which has been specified by the Heath’s own ecology team . By carrying out the work this way, we have avoided importing and exporting material from the Heath which would have meant many more vehicle movements.

The new dam is being built up with a slight slope – it falls east to west- to allow for water to run off the structure.

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In construction, the far edge of the new dam is slightly higher for drainage

If you are a regular on the Heath, over the coming weeks you will be able to watch the dam grow before your eyes. It’s final height is 2.5m above the current dam height (height of current causeway). We’ve put up a height indicator to help people visualise this. It’s a white wooden cross located in the south-west corner of the pond, in the work compound. If you are not able to see for yourself, we’ll be posting plenty of pictures on the blog.

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White cross indicated height of new dam

 

 

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