What was this massive chamber for ?

In this video we are in Manchester looking at the Moss brook. We follow the moss brook into an underground culvert in this urbex video. The culvert leads to a massive chamber with a flood control penstock. The penstock is a kind of flood gate that can control the flow of the moss brook in times of flooding. The moss brook can be diverted into a diversion tunnel that leads down to the river Irk. The area is Collyhurst in Manchester. Downstream of the moss brook was a lot of Victorian industry bleach works and engineering works. This Victorian industry needed protection from floods so in the Edwardian era around 1907 this flood control was built. We see the Moss brook in full flood and we understand why the whole victorian flood defence was built. We also go to look at the penstock control mechanism via a manhole shaft. We also look at a seewer overflow pipe, part of Manchester's sewer system. This is an underground urbex video exploring Victorian underground sewer and flood culverts.