The course of the river Don has been diverted twice, and the sides of the stream walled. It has also been necessary to raise the ground by at least twelve feet, and considering that the station covers an immense tract of land, this has been no slight undertaking.
The river Don's course has been altered twice, and its banks have been fortified.  It has also required raising the ground by at least twelve feet, considering that the station covers a vast area, making this a significant undertaking.