Much of the land in this area is very low lying and indeed some is a metre or two below sea level. We are therefore extremely reliant on dykes and drainage channels such as the one in the picture taken on this mornings walk. Much of the area was drained by Dutch engineers in the 19th century. There are some people who say that should sea levels rise then we will just return to where we were 150 years ago. A long way from the truth. The marshes that were drained were fresh water. Future incursions will have a salinity of around 30 parts per thousand. A major change from current conditions.