0 an area of low land that was once under the sea but that has been separated from it by dykes (= walls or channels built to prevent water covering an area): --
Other polders followed in 1657 and 1663.
From circa 1600 on, peat extraction became important and resulted in the formation of large ponds, which in turn would be made into polders later on.
Constructing polders in this way is called "inning" or "reclaiming" from the sea.
In the process valuable expertise was built up in throwing up banks, reclaiming polders and embanking rivers.
Other technological advances that have increased the carrying capacity of the world relative to humans are: polders, fertilizer, composting, greenhouses, land reclamation, and fish farming.
Starting around the 16th century, they took the offensive and began land reclamation projects, converting lakes, marshy areas and adjoining mudflats into polders.
The polders include 33 km of canals, 177 km of levees, and 129 hydrotechnical structures.
The first consists mainly of sand dunes and clayey alluvial soils in the polders.
