Hours later 
thanks to help from forums experts and tutorials I’m getting there… to the untrained eye it will do the job 
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2 Likes
Nice work… Quite intricate!
Inquiring mind here, just what is this?
Best,
Tommy
Hi Tommy
These are attenuation crates, they are stacked modular formate underground for flood water storage encapsulated in 1mm LLDPE plastic membrane
Carl