Geograph - photograph every grid square

Where the road to Morton Fen crosses the Roman Car Dyke, a water height gauge has been installed. Strangely, the data is not available from the Environment Agency web sites.

A 57-mile man made ancient drainage watercourse between Lincoln and Peterborough. The circumstantial evidence points to the skill of Roman engineers but documentary evidence is inconclusive, though it is generally assumed to be Roman.
It was originally thought to continue south of Peterborough to the Waterbeach canal, north east of Cambridge, but no link has been proven.

The Fens, also known as the Fenland, is a naturally marshy region in eastern England. Most of the fens were drained several centuries ago, resulting in a flat, damp, low-lying agricultural region.
A fen is the local name for an individual area of marshland or former marshland and also designates the type of marsh typical of the area, which has neutral or alkaline water chemistry and relatively large quantities of dissolved minerals, but few other plant nutrients.
Fenland primarily lies around the coast of the Wash; it reaches into four counties: Lincolnshire, Cambridgeshire, Norfolk and a small area of Suffolk, as well as the historic county of Huntingdonshire. In whole it occupies an area of nearly 1,500 sq miles.
Most of the Fenland lies within a few metres of sea level. As with similar areas in the Netherlands, much of the Fenland originally consisted of fresh- or salt-water wetlands, which have been artificially drained and continue to be protected from floods by drainage banks and pumps.