Strandwallen form one line/defense
The water behind this line is fresh water/becomes undeep fresh water from rivers er
Peat, an organic fuel consisting of spongy material
formed by the partial decomposition
of organic matter,
primarily plant material, in wetlands.Dode planten die daarin komen vergaan niet
--> new soil : peat
rise of sea level and as a
consequence the groundwater too
--> meters of peat layers