4.4 The marine clay landscape

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4.4 The marine clay landscape

After studying this section, you will be able to:

• Explain how the lower parts of the Netherlands have been formed during the Holocene
  
• Recognise the regions in the marine clay landscape and their features

What are myths (which is not true) about water and the Netherlands?

1. The NL has regions enclosed by dyke rings
2. We will always keep our feet dry because of expertise
3. Half of the Netherlands is below sea level
4. Our coastline has been shortened

Different polders

sea polder = zeepolder

peat polder = veenpolder

reclamed lakefloor = droogmakerij

IJsselmeerpolders = Example: Noordoostpolder (Flevoland)

When the sea is calm, clay or sand are being deposited

📌 Seapolder: 

• Dykes around the new land
  
• About sea level
• Sand and clay was brought by the sea
• Waddengebied plus Zeeland (North sea)

peat polder (Ch4.5)

reclaimed lakefloors

https://www.youtube.com/watch?v=fXu4kTxFEwI

Reclaimed lake floor

It is a polder.
How was it made?

1. First a ring dyke was built
2. Then the channel around it was dug
3. Then it was pumped dry and the water was transported away
   

Back in the day

Now

By sedimentation we get extra land along the coast. What type of polder is it?

1. sea polder
2. peat polder
3. reclamed lakefloor
4. IJsselmeerpolder

Where do we have most peat polders?

1. In the east of the NL
2. In the south of the NL
3. In the west of the NL
4. In the north of the NL

Why did we build the IJsselmeerpolders?

1. to protect us against flooding
2. to have more land for agriculture
3. to build a second airport
4. to travel faster from Randstad to the north

Dune area between Den Haag / Wassenaar / Noordzee

Is there any space for sea water, dunes etc in a densely populated area?

First residents of the Netherlands thought they lived in the sea, dry land on low tide and wet on high tide, so they build the first mounds*

Mounds (also named terps) = manmade hills, used to protect the people from the water. 

Salt marshes

The salt marshes are a little bit higher than the land behind the dykes, because the sea level kept rising, and the process of deposition kept going on.

In dutch called ''Kwelders''

3 ways to protect us better from the sea in the future:

1. to avoid more coastal erosion: beach nourishment (zandsuppletie)
2. give more space to the dunes: dynamic coastal management
3. tidal landscape supplies extra sediment

Beach nourishment

Dynamic coastal management

Protect the coast line by reinforcing dykes and extra sand:

Which uses has the zandmotor?

Fieldwork!

We are going to the zandmotor next Friday

We meet at 10.00, be there on time! 

Your first break will be on the beach

If you want to join, I will be leaving at 9.30 by bike.

THE END

Essence

During the Holocene, layers of sand and clay were deposited in the lower parts of the Netherlands. In the northern marine clay landscape, you can still find many mounds. Kwelders were reclaimed by building dykes and used for agriculture. In Noord- Holland, Zuid-Holland and Flevoland, polders can be found. In some of these, a great deal of human activity takes place. Marine clay is a good soil type for agriculture.