Did you know?

It is not wise to water your garden in the summer heat. In warm weather, the water evaporates quickly. This wastes a lot of water and the plants do not absorb it properly. 

Saving water

If we use water more wisely, we can save a lot of water in the garden. It is best to water your garden early in the morning or late in the evening. Then the water evaporates less quickly and the plants can absorb it better. It is also better to water the plants at the roots. That is where they need the water. A large part of the water evaporates from the leaves. And: it is better to water your garden thoroughly once a week than a little every day. This trains the plants to grow longer roots that can search deeper into the ground for water.

Water butt

A water butt is also useful in the garden. It allows you to collect rainwater during wet periods and reuse it when it is drier and warmer. A convenient way to reuse water!

Tip!

Go green in your garden and use as little stone as possible. In a green garden, water can slowly sink away and be absorbed by the plants to some extent. Water that falls on stones is immediately drained away into the sewer.

Because warm water contains less oxygen than cold water and temperatures can rise in summer, oxygen depletion often occurs. This causes fish to come to the surface to gulp air.

Lack of oxygen 

One of the most common causes is a lack of oxygen in the water. Warm water holds less oxygen than cold water. In summer, the oxygen concentration in stagnant or slow-flowing water can drop significantly. Fish then move closer to the surface. At this point, the water contains more oxygen, especially early in the morning when oxygen levels are at their lowest.

In winter and summer, the water levels in ditches, ponds, and canals vary. In summer, the water is higher than in winter. 
 

Winter

The water level is lower in the winter months than in the summer. More rain falls in winter and less water evaporates. The amount of precipitation is therefore greater than evaporation. A lower water level creates space in the ditches and lakes to collect rainwater. We then discharge the excess water back into the sea.

Summer

In summer, the water level is higher. It is warmer then, and more water evaporates than falls as rain. Demand for water is also higher in summer. Fields are sprayed with water during droughts. Polders are flushed with freshwater to prevent soil salinisation. In addition, we use more water for cooling and recreation in summer. That is why we raise the water level during these months. In this way, we create a buffer in our water system. 

When is winter or summer level?

We do not have a fixed start date for the winter or summer water levels. Water-level management is a forward-looking process. When conditions become drier in the spring, we store water and raise the water level. When conditions become wetter again in the autumn, we release more water. This ensures that our watercourses have more capacity to absorb heavy rainfall and this helps prevent flooding. 

Water Level Regulation Plans

There are many different areas, each with their own water level. They are set out in a Water Level Regulation Plan. Agreements regarding water levels sometimes need to be revised. Circumstances and insights can change. In such cases, we adjust the water level and set it out in a new Water Level Regulation Plan. 

A pumping station is a facility ('structure') that moves water from a lower to a higher level. This allows a water-level regulation area to maintain a specific water level. This water level refers to the height of the water in ponds, ditches, and canals relative to the Amsterdam Ordnance Datum (NAP). Within a defined area, we agree on the optimum water level, taking account of factors such as residential areas, agriculture, and nature.

Polders

A large part of the Netherlands consists of polders. In polders, the water authority maintains the water level in the ditches at a specific level. Pumping stations ensure that excess water—caused by rainfall, for example—is pumped out of the polder. 

Shrinkage

Because pumping stations remove water from the ground, shrinkage can occur, particularly in peat soils. This means that the soil no longer swells when it gets wet. The peat oxidises and can disintegrate, causing subsidence. Therefore, the water authority takes great care to manage the groundwater level so that the soil does not become too dry.

De Waterwolf

De Waterwolf is a catchtwater pumping station that transfers water to a catchwater (surface water) in another area. This pumping station has been in operation since 1920 to transfer excess water from the Reitdiep to lake Lauwersmeer. De Waterwolf drains the northwest of the province of Groningen (67,000 ha) and the kop van Drenthe (29,000 ha) to a level of -0.93 m NAP. This is also known as the Electra level, named after the former water authority that managed De Waterwolf.

Due to climate change, we are increasingly experiencing extreme rainfall. The sewage system cannot always cope with this; it can overflow, causing foul sewage water to appear on the streets. Additionally, water can remain in your garden for extended periods. Fortunately, we can also collect water in our gardens by creating a water-friendly garden!

How do you look after a water-friendly garden?

• Plants absorb water, whereas paving slabs do not. Therefore, it is important to lay as few paving slabs as possible in a garden. Water can drain more effectively in a green garden.
• A water butt can also collect rainwater. During periods of low rainfall, this water can be reused to water the garden. You can also choose to disconnect the downpipe, allowing water from the roof to flow directly into the green garden. If you have a larger garden, you could construct a wadi to collect water and allow it to slowly sink into the ground.
• By creating elevation differences in your garden, rainwater can flow more easily to the green areas of your garden or into a pond. Here, the water can seep into the soil and will not remain on the paving slabs. By situating the lower-lying areas further from your house, you reduce the risk of flooding near your home.

No, water from ditches does not always flow directly to the sea. A large part of the Netherlands consists of polders that lie below the Amsterdam Ordnance Datum (NAP). Water does not flow naturally to the sea from polders and may even be stagnant. As a result, the ditches in these low-lying polders fill up quickly. To prevent this, pumping stations remove the water.

Where does the water go?

Pumping stations transfer water to another area: the catchwater. In the case of De Waterwolf, this is lake Lauwersmeer. Water is pumped up from the Kommerzijlsterriet and the Reitdiep and transferred to lake Lauwersmeer. From there, excess water can be discharged into the Wadden Sea via locks at Lauwersoog.

Other types of water movement

Water can also move in other ways. For example, it can evaporate due to the sun, after which the wind carries away the moist air (and ultimately clouds). This can lead to lower water levels, especially in the summer. In addition, water from ditches is used rgularly for agriculture or industry. Farmers extract groundwater to irrigate their crops during periods of drought. This water then ends up in the agricultural land.

If your house is situated below NAP, this means that the ground on which your house stands is lower than the Amsterdam Ordnance Datum. This is a reference height, approximately equivalent to the North Sea's sea level.

Flood risk

Due to climate change, we experience extreme weather, such as heavier rainfall and more severe storms, more often. The likelihood of flooding during extreme weather is higher when your house is situated below NAP. Rivers and ditches can also cause issues due to an excess of water affecting homes in low-lying areas.

Protection of dykes and flood defences 

Fortunately, we also have dykes and flood defences that protect our areas and reduce the risk of flooding. However, partly due to more extreme weather conditions, our country is becoming more vulnerable to flooding and water damage.

Will I Flood?

On the website Overstroomik.nl, you can check how high the water will reach near you in the event of a flood. It also provides tips on how to prepare properly for flooding.