Major systems commonly include bypass tunnels, greenbelts, and roads which are used to handle the runoff which exceeds the capacity of the minor drainage system.

大型系统通常包括旁路通道，绿化带和道路，用来处理超过小型排水系统处理能力的径流。

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The authority said planning permission for apartments on the site had been given in December 2005 but no development had taken place since, aside from minor drainage work.

BBC: Mansfield General Hospital site

They say that the area is environmentally damaged anyway, thanks to drainage and over-grazing, and that the new wind farms would have only a minor impact.

ECONOMIST: Wind farms