aerial photograph of Cowbridge Lincolnshire England UK showing the convergence of the West Fen Drain, Stone Bridge Drain, Cowbridge Drain, Maud Foster Drain and Frith Bank Drain, part of the Witham Navigable Drains. While there had been many previous attempts to drain the fens, the present day system owes its origins to an Act of Parliament in 1801 and the plans of engineer John Rennie. The lock in the lower part of the photo is Cowbridge, the last lock still operational from an origianl four constructed.