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.

Rain barrel

A rain barrel is also useful to have in the garden. It allows you to collect rainwater during wet periods and reuse it when it is drier and warmer. A handy way to (re)use 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 (in part) by the plants. 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.

Oxygen deficiency 

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 fresh water to prevent soil salinization. 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 about looking ahead. When it becomes drier in the spring, we start to store water and raise the water level. When it becomes wetter again in the fall, we drain more water. This ensures that we have more space in our waterways to collect large amounts of rainwater and prevents flooding. 

Level decisions

There are many different areas, each with its own water level. This is laid down in a water level decree. Agreements on water levels sometimes need to be renegotiated. Circumstances and insights can change. We then adjust the water level and lay this down in a new water level decree. 

A pumping station is a facility (‘engineering structure’) that transfers water from a lower to a higher level. This allows a water level area to maintain a certain water level. This water level is the height of the water in lakes, ditches, and canals relative to Normal Amsterdam Level (NAP). Within a defined area, we agree on the best water level. In doing so, we take into account factors such as housing, agriculture, and nature.

Polders

A large part of the Netherlands consists of polders. Here, the water level in ditches is kept at a certain level by the water board. Pumping stations ensure that excess water, caused by rainfall for example, is pumped out of the polder. 

Settling

Because pumping water removes water from the soil, subsidence can occur, especially in peat soil. This means that the soil can no longer swell when it gets wet. The peat soil oxidizes and the peat can pulverize, causing land subsidence. The water board therefore takes great care in managing the groundwater level so that the soil does not become too dry.

The Waterwolf

The Waterwolf is a pumping station that transfers water to a reservoir (surface water) in another area. This pumping station has been in use since 1920 to transfer excess water from the Reitdiep to the Lauwersmeer. The Waterwolf drains the northwest of the province of Groningen (67,000 ha) and the northern tip of the province of Drenthe (29,000 ha) to a level of -0.93 m NAP. This is also known as the Electra level, named after the former Electra water board that managed the Waterwolf.

Climate change means we are increasingly faced with extreme rainfall. The sewer system cannot always cope with this: the sewers can overflow, causing dirty sewage water to end up on the streets. Water can also remain in your garden for longer periods of time. Fortunately, we can also collect water in our gardens by creating water-friendly gardens!

How do you create a water-friendly garden?

• Plants absorb water, tiles do not. That is why it is important to lay as few tiles as possible in a garden. Water can drain away better in a green garden.
• A rain barrel 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 downspout, allowing water from the roof to flow directly into the (green) garden. If you have a larger garden, consider constructing a wadi to collect water and allow it to slowly sink into the ground.
• By creating differences in height in your garden, rainwater can flow more easily to the green areas of your garden or into a pond. Here, the water can sink into the soil and does not remain on the tiles. By creating the lower areas further away from your house, you reduce 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 Normal Amsterdam Level (NAP). Water does not flow away to the sea by itself here and sometimes even stands still. The ditches in these low polders therefore fill up quickly. To prevent this, pumping stations pump the water away.

Where does the water go?

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

Water displacement other ways

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 regularly used 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 below N.A.P., this means that the ground on which your house stands is lower than Normal Amsterdam Level. This is a reference height, which is approximately equal to sea level at the North Sea.

Flood risk

Climate change means we are experiencing more extreme weather, such as heavier rainfall and more violent storms. The risk of flooding during extreme weather is higher if your home is below sea level. Rivers and ditches can also cause flooding due to excess water in low-lying areas.

Protection of dikes and flood defenses 

Fortunately, there are also dikes and flood defenses that protect our areas and limit the risk of flooding. However, partly due to more extreme weather conditions, our country is becoming more vulnerable to flooding and water damage.

Am I overflowing?

On the website Overstroomik.nl, you can check how high the water will rise in your area in the event of flooding. It also provides tips on how to prepare for a situation of flooding.