The Iška River: From Spring to Faucet

The Iška River: From Spring to Faucet

Conceptual design: Dr. Aleš Smrekar and MSc. Mateja Šmid Hribar

Authors: Dr. Bojan Erhartič, Dr. Aleš Smrekar, MSc. Mateja Šmid Hribar, Jernej Tiran

Difficulty level: 11 to 14 years

Estimated time: 10 to 20 minutes

Language: English (links are available only in Slovenian)

Translation: DEKS d.o.o.

eLecture is a part of educational trail


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Slovenia is one of the countries with the most water in Europe. But do we really know how to appreciate this precious resource? In the past, Slovenians were more aware of the value of water and they also attributed special importance to it.

Salameander will lead you on this adventure along the Iška River all the way to the Brest Pumping Station, where drinking water is drawn.

Before setting out on this journey, check out where the Iška River is located and read more about it at the Dedi website.

You can also read the legend about how it was created.

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On average, Slovenia receives over 1,500 mm of precipitation per year, making it one of the wettest countries in Europe. However, the precipitation isn’t evenly distributed. This mostly depends on the terrain, distance from the sea, and the wind: near mountain barriers the air rises, cools, and then releases precipitation.

The Storm. (Photo: Blaž Košak, SOKol, ARSO)

Look at the thematic map of the average annual precipitation in Slovenia and choose the correct answer.


That’s right. The most precipitation is in the Julian Alps. To the northeast there’s less precipitation, and so droughts are relatively common in the Mura Valley in the summer.


No — check the map again and look for the black and purple areas. That’s where there’s the most precipitation. Got it?

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Some of the precipitation remains above the ground (as surface water) and some sinks into the earth (creating groundwater).

Water comes to the surface through many springs in the ravines in the Iška watershed. After about 20 km, the river flows out of the Iška Gorge into a gravelly plain. Below the surface there’s a lot of groundwater, which is mostly the water of the Iška River.

Which of the following types of water do you know about in the Iška watershed? More than one answer is possible.

If you don’t know what a term means, look it up in an online dictionary.


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The hollow rock in Iška Gorge. (Photo: Mateja Šmid Hribar)

Congratulations! You know a lot about different kinds of water!


Not quite. Try a little harder.

Nope. Help yourself with online dictionaries to understand the terms. Then it will be a piece of cake (with water :))!

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Perennial and intermittent springs, which form flashy streams and creeks, join to create increasingly larger rivers.

This is called a river network.

Look at the map on the right, showing the branching river networks of the Iška and the Želimeljščica.

The main tributary of the Iška River is the .


The Iška watershed. (Cartography: Manca Volk)

Outstanding! Did you know that the old Slovenian word "zala"; means "beautiful"?


Don’t joke around—this is serious stuff!

Think of a popular Slovenian brand of bottled water and you’ll get it. And the name’s written with a capital letter, of course.

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When the Iška leaves the Iška Gorge, its slope decreases and it has less and less power. This is why it once twisted into many bends, or meanders, and during heavy rains it would flood the Ljubljana Marsh.

Over the past few centuries, people tried to tame the river by cutting off its natural bends to shorten its course and "squeeze" it into a much straighter river channel.

Compare this map adapted from the cadastral survey under Emperor Francis I and a modern aerial photo.

Look for the meander on the old map and choose the answer below for what’s in its place today:



That’s great! Keep up the good work!


Sorry, that’s not right. Don’t guess; check the photo and you’ll get it!

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Drought in the Sečovlje saltworks in 2008. (Photo: Viktor Šmid)

The Iška carried most of the material that it carved out in the Iška Gorge to the gorge’s fringes, where it mostly deposited it as gravel and sand.

When the small spaces between pebbles and grains of sand fill with water, this is groundwater.

The groundwater level below the surface fluctuates mostly due to changes in the amount of precipitation during the seasons and various human activities.

Which of these natural phenomena makes groundwater levels fall the most?

If it’s taking too long, just click the button on your mouse.


You’re doing great! To deal with a drought, saving water is what it’s all about!


Hey, stop joking! Now click the right answer fast—without any doubt!

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The Iška River attracted a lot of attention in the news in 2010.

Soon after it overflowed its banks and flooded, it mysteriously disappeared into the ground near the village of Iška vas.

However, this isn’t unusual for the Iška. Valvasor wrote about this in The Glory of the Duchy of Carniola in 1689.

The river sinks into the ground especially when the rushing water flushes small particles out of the bed that had been preventing it from draining away.

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Dry riverbed of the Iška River. (Photo: Aleš Smrekar)

Watch the recording of the Iška River disappearing and write down the new name a local man suggests as a joke for Iška vas: vas.


Great! What name would you suggest? Continue.


No, no ... watch the recording again, and you’ll get it!

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Take a break and put the blocks together to see a drawing of the Iška Fan (illustrated by Marjan Pečar).

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The Iška River often has flash floods because after heavy rains its flow dramatically increases in a short time. The rates of flow are highest in the fall, and lowest in the summer.

There’s a hydrometric station along the Iška to monitor the river; this is one of the stations in the network monitored by the Slovenian Environment Agency. They record not only water conditions, but weather too.

Look at a hydrometric station

Weather conditions are monitored in the weather part of the station, and water conditions in the hydrometric part.

Match the words on the right with their definitions on the left. Two of the rectangles on the right go into one of the gray areas next to the words on the left. Move the rectangles one on top of the other.

device for measuring water level
device for measuring weather conditions
Staff gauge


Super! Take a trip out to the hydrometric station in Iška vas some time!


Uh oh, take a look at the picture again and you’ll get it for sure.

A hydrometric station. (Illustrated by Marijan Pečar)

A hydrometric station. (Illustrated by Marijan Pečar)

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In the past, waterpower was used to drive flour mills, sawmills, and various workshops. Today it’s mostly used for hydroelectric plants and turned into electricity.

Sawmills and flour mill at Iška river's millrace

Watch the video and figure out what’s happening.

Start the video by clicking on the photo.


Great! Isn’t that a good way to use waterpower? Continue down the river!


Oh, come on! Zzzzz ....? Got it?

Sawmills and flour mill at Iška river's millrace. (Illustration: Marijan Pečar)

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Long ago already, the people living on the Iška Fan dug many wells into the gravel, only a few meters below which there’s groundwater. Later on they also bored wells.

In 1981 these were joined by the Brest Pumping Station, which has increasingly replaced drinking water supplied from private wells, although these are still used for irrigation.

Look at the locations of the wells on Iška Fan

Today traditionally dug wells are (more than one answer may be right):


Dug well. (Photo: Andreja Konovšek)

That’s right; you’re thinking in the right direction.


Not quite. Try a little harder.

Come on! We’ve still got the wells, but they’re hardly ever used for drinking water anymore, right? Now it’ll be easy!

Wells on the Iška Fan. (Cartography: Manca Volk)

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The groundwater in the Iška Fan is an important source of drinking water. It’s drawn for the public water system at the Brest Pumping Station, which is one of five pumping stations in the Ljubljana water supply system, even though it’s relatively far from the city.

The Brest Pumping Station supplies about one-tenth of the drinking water for Ljubljana’s residents, and it also supplies most of the nearby settlements.

The Brest Pumping Station. (Illustration: Marijan Pečar)

The company Javno Podjetje Vodovod-Kanalizacija d.o.o. draws drinking water at the Brest Pumping Station from only of fifteen bored wells because some wells are not active. They’re 26 to 100 m deep. Check

Congratulations, you counted right! You’re doing really well!


No, that’s not right! If you don’t know how many wells are active, look at the illustration of the Brest Pumping Station and count the wells marked with the color that usually indicates water.

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Drinking water flows from the Brest Pumping Station to the water supply system that also serves Ljubljana. This is one of the longest water supply systems in Slovenia, with over 1,100 km of water mains!

Piper will explain the path the drinking water takes.

What does Salameander say?

Put the statements on the right in the correct place next to the words on the left.

Water supply system
Sewage system
Pumping station
Network of pipes carrying drinking water from the pumping station to consumers.
Network of pipes carrying wastewater from consumers to treatment plants.
Water storage area.
Place where drinking water is pumped.


You’re as clear-headed as clear water! You’ve become a real helper for Piper!


Hmm. If a reservoir stores water and if a sewer system carries wastewater to treatment plants, then the choice is easy, right? Try again!

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Slovenia is rich in water resources, and so the people living here don’t have major problems with drinking water supplies. But it’s still important to use it wisely and not waste it!

An adult needs two to five liters of water a day simply to survive, let alone for our modern lifestyle!

We need twenty to fifty liters of clean water a day to prepare hot meals and for basic personal hygiene.

Just think about it! Look at the Primavoda website to see how many liters of water you use if you let the faucet run while brushing your teeth. Choose the right answer.


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Drinking water from a drinking fountain. (Photo: Albert Kolar, SOkol ARSO)

That’s right. So keep turning off the water when you don’t really need it. Shall we flow along?


Nope! Use the link for help and you’ll get it.

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Today’s lifestyle means that water is very threatened by pollution.

Surface water and groundwater are especially polluted by direct discharge of household and industrial waste, leaching of fertilizer and pesticides from farmland, and of course leaking of dangerous substances from illegal dumpsites.

Slovenia uses water protection areas to safeguard drinking water sources.

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Drinking water is endangered mostly by hazardous waste. (Photo: Blaž Komac)

Look up the locations of water protection areas on the Iška Fan

Where are the limits on activity least strict?




Nope! Take a good look at the map and think logically. Do it again!

Water protection areas on the Iška Fan. (Cartography: Manca Volk)

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Let’s repeat!

Upstream, the Iška River flows along the surface, and so it’s water. Many flashy streams and creeks join together to form larger watercourses, including rivers. This creates a network.

When the Iška River reaches the gravelly plain, much of the water sinks into the ground. When the small spaces between pebbles and grains of sand fill with water, this is .

Some of the water remains in the Iška River and, because its slope decreases, it has less and less power. This is why it twisted into many bends, or , before people straightened it.

In the past people living along the Iška used the waterpower for wood, and now the water is to supply drinking water.


Excellent! The question was hard, but you really learned a lot!

One more question to go—a piece of cake for you!


That’s not right. Look at the material again and you’ll get it.

That’s not right. Look at the material again and you’ll get it.

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Today it seems natural that drinking water comes out of the faucet and that we’ve got plenty of it. Drinking water has been and will remain a precious resource that the wellbeing of all human societies on Earth depends on.

The Iška River on the Ljubljana Marsh. (Photo: Viktor Šmid)

Especially in certain parts of Asia and Africa, there have been quarrels over water resources, which could lead to armed conflicts in the future. Take a look at the clip on the war over water in the Darfur region of Sudan.

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Fortunately, in Slovenia we’ve still got enough safe drinking water to enjoy.

Everyone can help keep our rivers, groundwater, lakes, and sea from being polluted.

A river pool in the upper stream of the Iška river. (Photo: Mateja Šmid Hribar)

Start saving water. Mark three ways to use water wisely.


Cheers! Well done. Until you visit the Iška River Meander Nature Trail, drink a lot of tap water, which — as you well know — is truly precious. See you!


Not quite. Try a little harder.

Nope. I suggest that you think hard before clicking. Using detergent in a clean creek and throwing away an old bicycle aren’t wise at all.