 The fen drains could not naturally discharge into Vernatt's Drain.There was a history of windmill-driven pumps and later small steam engines across The Fens but the two engines at Pode Hole were the first of the large scale pumping efforts, and an encouragement to later schemes.John Rennie was consulted in 1818, and he proposed diverting the upper reaches of Vernatt's Drain from the Welland to the Witham to improve the fall.