Due to its location in flat , low-lying fenland near the sea , the town of Boston has always been at risk of flooding . The buttress on the south-west corner of the tower has been used since the eighteenth century for keeping a record of the heights and dates of flooding of the church by the River Witham . Flood defences were improved following the North Sea flood of 1953 . The church was flooded in 1978 and again on 5 December 2013 , when the North Sea flood of 2013 resulted in of water inside and outside the building
North Sea flood of 1953
North Sea flood of 1953
St Botolph's Church, Boston