Tuesday, August 5, 2014

The Clever Dutch and How They Manage Water

This is a post we also did for The Wilderness Classroom.

Have you ever tried to build barriers to protect a sandcastle from waves on an ocean beach? At a much bigger scale, this is the same problem The Netherlands faces (The Netherlands is sometimes called Holland and people from the Netherlands are the Dutch).  Almost half the country is either below sea level or less than 3 feet above sea level.  The three largest cities (Amsterdam, Rotterdam, The Hague) are all in these low-lying regions.

Building a sand castle in a flood prone area
While in the Netherlands, we visited the Zuiderzee (pronounced zow-der zay) Museum, to see an exhibit about floods in Dutch history.  We were amazed at the number of serious floods the country has experienced. To protect their country from floods, the Dutch have built many dikes, barriers, and pumps. 

List of serious floods in Dutch history at Zuiderzee Museum

Many Ways to Protect Against Floods:  The Clever Dutch
The Dutch are threatened by flooding from both the sea and from rivers.  To keep low-lying land free of water, they use dikes, which are walls that are built to keep water out.  Along with the dikes, they use continuously operating pumps.  If the pumps stopped, water would eventually seep back into low-lying land. 

After a serious flood in 1916, they used one massive dike to close off part of the ocean.  The Zuiderzee, an inlet of the North Sea, caused many floods.  So the Dutch built a 20-mile (32km) long dike to close off part of it off.  When it was completed in 1932, it created the largest freshwater lake in Western Europe, called the Ijsselmeer.

Along the dike that holds in the Ijsselmeer
Another strategy the Dutch use is called “room for water.” Sometimes, they have to let water take over some land, in order to protect the rest.  This could be water from the ocean or from rivers.  With rivers, they make “room for the river” by making sure rivers have plenty of bends -- straight rivers can run too fast, eroding dikes quickly, with less time to react to floods.  They also create two dikes around key waterways, an inner dike for normal water levels and an outer dike in case water goes over the inner dike in a flood. 

In addition, a key part of the Dutch’s strategy is a massive series of barriers that close off water channels if water levels rise too high:  we visited one, called the Maeslantkering (pronounced mahs-lahnt-caring).

The Maeslantkering
When you visit the Maeslantkering, the first thing that strikes you is its size:  it’s absolutely enormous.  It’s a set of huge curved doors that block off the ocean when sea level rises too high.  One arm that swivels the doors into place is as long as the Eiffel Tower lying on its side – and it weighs twice as much!

One arm of the Maeslantkering – Eiffel Tower on its side!

It weighs even more when it’s filled with water, which is how it works.  First the doors slide into place over the channel.  Then, water is pumped into the hollow frame, which then sinks the doors into the channel – making them extremely heavy and stable. 

The Maeslantkering provides protection against sea level rise of up to 5 meters (16 feet).  The gates are only closed if sea level is expected to rise at least 3 meters (10 feet).  Except for an annual test, the gates have been closed only once since being completed in 1997. 

In front of the Maeslantkering

The Maeslantkering is part of the Delta Project, a huge system of dikes and storm surge barriers created to protect the southwestern part of the Netherlands. The Delta Project was started following a major flood in 1953 that resulted in 1,836 deaths and a lot of property damage, and caused the Dutch to overhaul their water management. 

How Could Climate Change Affect The Netherlands?
Two big challenges the Dutch face from the warmer temperatures created by climate change are rising sea level and stronger storms.

Rising sea level:  Warmer temperatures cause glaciers and ice sheets to melt, with the water eventually running into the oceans.  In all the glaciers and ice sheets of the world, there is enough water to raise sea levels about 75 meters (about 250 feet).  The majority of glaciers and ice sheets are located in Greenland and Antarctica.  To date, sea levels have risen about 8 inches, but forecasts are for it to rise between about 1 and 6 ½ feet by 2100.

Harriet glacier in Svalbard, Norway

Stronger storms:  Warmer air can hold more moisture.  Think about the bathroom mirror steaming up after a warm shower (try a cold shower – the mirror will be clear).  According to the 2012 Yale forum on Climate Change and the Media, the Earth’s air is about 4% more humid than it was 30 years ago.  This added water in the atmosphere provides more fuel for storms (there’s simply more water that can rain down).  Plus, storms often form over oceans.  Warmer oceans provide more fuel for storms then colder oceans. 

So rising sea level will be something the Dutch watch closely over time, to make sure their barriers and systems provide adequate protection. 

The water management expertise the Dutch have built up over the centuries will only become more and more valuable as rising sea levels and more floods affect communities around the world.  Already, the Dutch are sharing their expertise, working with officials in New York, Vietnam (Mekong Delta), Bangladesh and other places on water management plans.




Thanks
Many thanks to Alexander Verbeek (Strategic Policy Advisor Global Issues, Ministry of Foreign Affairs, Netherlands), who I connected with on Twitter several months ago, for his recommendations on places to visit in the Netherlands.  He also connected us with Dr. Raimond Hafkenscheid (Strategic Advisor for Water and Adaptation, Department of Climate, Energy, Environment and Water at the Ministry of Foreign Affairs in The Netherlands).  Dr. Hafkenscheid graciously met with us and taught us about the Dutch approach to water management.  We also heard about an amazing event he recently organized:  kids building sandcastles.  Why were they building sandcastles?  Watch the video here to find out.

Study Guide Questions
1. What portion of the Netherlands is below sea level or within 3 feet of sea level?
2. Describe why the Dutch have been dealing with virtual sea level rise for a long time.
3. What are two challenges the Dutch face from climate change?







No comments:

Post a Comment

Comments / Thoughts are Welcome!