The River Welland is a lowland river in the east of England, some 65 miles (105 km) long. It drains part of the Midlands eastwards to The Wash. The river rises in the Hothorpe Hills, at Sibbertoft in Northamptonshire, then flows generally northeast to Market Harborough, Stamford and Spalding, to reach The Wash near Fosdyke. It is a major waterway across the part of the Fens called South Holland, and is one of the Fenland rivers that were laid out with washlands. There are two channels between widely spaced embankments with the intention that flood waters would have space in which to spread while the tide in the estuary prevented free egress. However, after the floods of 1947, new works such as the Coronation Channel were constructed to control flooding in Spalding, and the washlands are no longer used solely as pasture, but may be used for arable farming.

The Fens or Fenlands in eastern England are a naturally marshy region supporting a rich ecology and numerous species. Most of the fens were drained centuries ago, resulting in a flat, dry, low-lying agricultural region supported by a system of drainage channels and man-made rivers and automated pumping stations. There have been unintended consequences to this reclamation, as the land level has continued to sink and the dykes have been built higher to protect it from flooding.