The Netherlands: General Presentation and the Making of Polders

30 min

Let's begin

Rwanda's marshlands, such as those of the Nyabarongo and Akanyaru valleys, are drained and farmed for rice and vegetables. The Netherlands went much further: over several centuries it drained lakes and even part of the sea, and turned the bed into farmland. A saying there goes, "God created the world, but the Dutch created the Netherlands." About a quarter of the country lies below sea level, yet in 2025 it exported agricultural goods worth €137.5 billion, making it one of the largest exporters of farm products in the world (Statistics Netherlands, CBS, January 2026). How can such a small, low-lying country farm so successfully?

Definition

Polder: an area of low-lying land reclaimed from the sea, a lake or a marsh, enclosed by dykes and kept dry by drainage and pumping. Dyke (dike): a long embankment built to hold back the sea or a river. Land reclamation: making new land, or usable land, from sea, lake or marsh.

General presentation of the Netherlands

Feature	The Netherlands
Location	North-west Europe, on the North Sea; borders Germany (east) and Belgium (south)
Area	About 41,500 km² including inland and coastal waters, roughly one and a half times the size of Rwanda (CBS)
Population	About 18 million (CBS, 2025), one of the most densely populated countries in Europe
Capital	Amsterdam (the government sits in The Hague)
Relief	Very flat; about a quarter of the land is below sea level, mostly in the west and north; the highest point in the European Netherlands is only 322 m (Vaalserberg)
Rivers	The deltas of the Rhine, Maas (Meuse) and Scheldt
Climate	Cool temperate maritime: mild winters, cool summers, rain in every month (about 800–900 mm a year)
Economy	Highly developed: trade (Rotterdam is Europe's largest port), industry, services and very intensive farming

How a polder is made

Build a dyke around the area to be reclaimed, closing it off from the sea or lake.
Pump out the water. In the past windmills did this; from the 19th century steam pumps (the Cruquius station helped drain the Haarlemmermeer lake by 1852), and today electric and diesel pumps.
Dig a ring canal around the inside of the dyke and a network of drainage ditches. Rainwater and seepage collect in the ditches and are pumped up into the ring canal, which carries it out to the sea or a river.
Prepare the soil. The new land is salty and wet. In the Flevoland polders reeds were sown, even from aircraft, to dry out the soil; rain then washes out the salt. Drainage pipes are laid under the fields.
Grow pioneer crops such as rape and cereals, then add fertiliser and start ordinary farming.
Settle the land: build roads, farms, villages and towns in a planned pattern.

The Zuiderzee and Delta Works

The Zuiderzee Works turned a shallow inlet of the North Sea into a freshwater lake and new land. The Afsluitdijk, a dam about 32 km long completed in 1932, closed off the Zuiderzee; the water behind it became the IJsselmeer. Large polders were then drained inside it: the Wieringermeer (1930), the Noordoostpolder (1942), Eastern Flevoland (1957) and Southern Flevoland (1968). The last two now form the province of Flevoland, created in 1986.

The Delta Works followed the North Sea flood of 1 February 1953, which killed more than 1,800 people in the south-west. Dams, sluices and storm-surge barriers were built across the river mouths; the last major work, the Maeslantkering near Rotterdam, was finished in 1997.

Definition

Ring canal: a canal around the inside edge of a polder that collects pumped water and carries it away. Storm surge: a rise of sea level caused by strong winds and low air pressure, which can push the sea over coastal defences.

Worked example

Worked example 1: comparing area. The Netherlands covers about 41,500 km² and Rwanda 26,338 km² (NISR). How many times larger is the Netherlands?

41,500 ÷ 26,338 ≈ 1.6. The Netherlands is about one and a half times the size of Rwanda, yet it has about 18 million people to Rwanda's 13.2 million (NISR, Census 2022).

Worked example

Worked example 2: pumping a polder. A polder of 50 km² receives 800 mm of rain in a year, and about half of it must be pumped out (the rest evaporates or is used by plants). What volume must be pumped? (Illustrative figures.)

Area = 50 km² = 50,000,000 m². Water to pump = 0.8 m × 0.5 × 50,000,000 m² = 20,000,000 m³ a year, about 55,000 m³ every day. This is why pumping stations must run all year.

Warning

A polder is not just any farmland. It must be enclosed by dykes and kept dry by artificial drainage. Draining a marsh in Rwanda for rice makes reclaimed land, but it is only a polder if the area is diked and its water level is controlled.

Rick Steves' Europe: polders and windmills in the Netherlands. As you watch, list the steps used to keep a polder dry.

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Practice

Define a polder, a dyke and land reclamation.
Describe the relief and climate of the Netherlands.
List the six steps in making a polder, in order.
Why were reeds sown on newly drained land in Flevoland?
Name the dam that closed off the Zuiderzee and the lake it created.
What event led to the Delta Works, and what was their purpose?
A polder of 20 km² must have 0.4 m of water pumped from it in a year. Calculate the volume in cubic metres.
"Rwanda's marshlands could be farmed like Dutch polders." Give one argument for and one against.

Show answersHide answers

Polder: low-lying land reclaimed from sea, lake or marsh, enclosed by dykes and kept dry by drainage and pumping. Dyke: an embankment that holds back the sea or a river. Land reclamation: making new or usable land from sea, lake or marsh.
Relief: very flat and low, about a quarter below sea level; highest point only 322 m. Climate: cool temperate maritime, mild winters, cool summers, rain in all months.
Build a dyke; pump out the water; dig a ring canal and drainage ditches; prepare the soil (reeds, drains, washing out salt); grow pioneer crops; settle the land with roads, farms and villages.
Reeds take up a lot of water and so help dry out the soil, and they stop other weeds from taking over while the land is prepared.
The Afsluitdijk; the IJsselmeer.
The North Sea flood of 1 February 1953. To protect the south-west from the sea by closing or controlling the river mouths with dams, sluices and storm-surge barriers.
20 km² = 20,000,000 m²; volume = 0.4 × 20,000,000 = 8,000,000 m³.
For: Rwanda already drains marshes for rice and vegetables, and controlled drainage with ditches and pumps could raise yields. Against: Rwanda's marshes are wetlands that store water, prevent floods and support wildlife, and full polder systems need costly dykes, pumps and electricity; REMA protects many wetlands. Accept reasoned answers.

Sources and credits

Statistics Netherlands (CBS), Value of agricultural exports up by over 8 percent in 2025 (16 January 2026); CBS population and area statistics; National Institute of Statistics of Rwanda (NISR), Fifth Population and Housing Census 2022. Facts used as stated.
Polder, Zuiderzee Works and Delta Works: Wikipedia contributors, Wikipedia, CC BY-SA 4.0, adapted by Ganzaa.
Photo: KinderdijkMolens02, Lucas Hirschegger, Wikimedia Commons, GFDL and CC BY-SA 3.0.
Photo: Aerial photograph of Afsluitdijk, Netherlands Institute for Military History, Wikimedia Commons, CC BY-SA 4.0.
Video: Netherlands: Polders and Windmills, Rick Steves' Europe, embedded from YouTube.
Figure 1, table, worked examples and exercises: written by Ganzaa.

This lesson adapts CC BY-SA material and is shared under CC BY-SA 4.0.

1General presentation of the Netherlands

2How a polder is made

3The Zuiderzee and Delta Works

General presentation of the Netherlands

How a polder is made

The Zuiderzee and Delta Works