Check water storage capacity

Every year, we check part of our management area to ensure that the ditches are still the right size to provide sufficient water storage capacity. We call this the water storage capacity inspection.

When there is heavy rainfall, it is important that ditches can store water. We therefore check whether the tertiary ditches still meet the correct dimensions. Tertiary ditches are ditches that mainly serve a water storage function; they do not have a major impact on the water supply and drainage in the water system. Examples include ditches in contiguous nature reserves or ditches on the land of a single private owner. Vegetation may remain in tertiary ditches. The plants contribute to water quality and life in and around the ditch. However, these ditches must be able to store water, which means they must not silt up. We check this during the inspection of water storage capacity.

Terms and Conditions

The rules for the maintenance of ditches and associated structures (such as culverts, bridges, weirs, and dams) are laid down in theMaintenance Ordinance. TheWater Registerspecifies where the ordinance applies. It states the minimum dimensions (width and depth) that ditches must be maintained to and by whom.

How it works

You will receive advance notice of the inspection of the water storage capacity. If the ditch no longer meets the dimensions, you will receive a warning letter (intention to impose administrative coercion). This means that dredging will be required. You will have one year to do this. You must dredge the ditch down to the solid bottom, or until the dimensions specified in the Land Registry have been achieved. If the ditch is still not in order after a year, you will receive a so-called administrative enforcement order from us, and the enforcement process will commence.

Contact persons

The inspection team can be reached every working day on 072-582 8282, or via the contact form.

Frequently asked questions about water storage capacity

What is the chimney's water storage capacity?

During the inspection of water storage capacity, we check tertiary ditches for:

Silting: a ditch is silted up when it is completely overgrown and the marshy, boggy soil is (almost) passable. The ditch then turns into 'land' and can no longer store water. At the lowest permissible level according to the water level decree, there must still be water in the ditch.
The ditch must be fully connected to other ditches. This allows water to flow into the tertiary ditches during precipitation. Culverts must therefore be clean. Silt, fallen branches, and other objects must not obstruct the flow through the culverts.

Which locks are checked?

We check the water storage capacity of all tertiary waters in an area in the chimney. The Legger waters register specifies which ditches are tertiary. Using the aerial photograph and Legger waters, we determine which tertiary waters may have a decrease in water storage capacity. We then inspect this selection of ditches outside.

What should I do if the ditch is silted up?

If the ditch is silted up, it must be dredged. You have one year to do this. You can do this yourself or hire a contractor. The ditch must be dredged down to the solid bottom or to a minimum water depth of 30 centimeters across the entire width of the ditch.

Contaminated/polluted dredged material

The dredged material may contain litter. In addition, the dredged material may also be contaminated with heavy metals such as copper, lead, zinc, or pesticides. If you suspect that the dredged material in the ditch is contaminated, you can have it tested. If the dredged material is indeed contaminated, the water board will reimburse the costs of sampling and the additional costs associated with the removal of the contaminated dredged material.

During which period am I allowed to dredge?

The best time for dredging is outside the breeding season. The breeding season runs from March 15 to July 15. This means that the work can be carried out year-round, except between March 15 and July 15. Are there any legally protected species in the ditch? If so, contact an ecological expert to determine a suitable period for the dredging work.

I received advance notice.

Before the inspection of water storage capacity takes place, HHNK sends a preliminary notice to those responsible for maintenance. In the preliminary notices, we indicate when the inspection will take place.

I have received a notice of administrative enforcement.

If the water storage capacity assessment shows that a ditch for which you are responsible for maintenance does not meet the dimensions specified in the Water Register, you will receive a notice of administrative enforcement. In this notice, we will request that you dredge the ditch before a specified date. You will be given ample time to do so. After this date, we will inspect the ditch again. This letter specifies exactly which ditch is involved.

I have received an administrative enforcement order.

If it appears that the ditch for which you are responsible for maintenance still does not meet the correct depth after the date specified in the letter (intention to impose administrative coercion), you will receive an administrative coercion order. In the administrative coercion order, we will ask you once again to dredge the ditch before a specified date. After this date, we will check the ditch again.

What if the work has not been carried out by the date specified in the administrative order?

If it appears that the ditch still does not meet the correct dimensions after the date specified in the administrative enforcement order, we will contact the party responsible for maintenance. Ultimately, we can then carry out the work (or have it carried out) at the expense of the party responsible for maintenance, and we will also impose a penalty. These costs are considerably higher than if the party responsible for maintenance carries out the work themselves or has it carried out. As a water manager, we are obliged to have waterbed and ecological research carried out in addition to dredging, whereas this is usually not the case for private individuals or farmers. Such research costs at least €1,500. We charge an additional €250 in administrative costs and may impose a fine of between €100 and €300.

Frequently asked questions about ditch maintenance and chimney sweeping

Who is responsible for maintaining the locks?

The water board, the province of North Holland, municipalities, nature organizations, the railway operator, and Rijkswaterstaat are responsible for maintaining most of the ditches in North Holland. However, there are also ditches that must be maintained by the owner of the plot of land along the ditch. If you live next to a ditch, you are responsible for maintaining the half of the ditch that borders your plot. The owner of the plot on the other side is responsible for maintaining the other half. Cooperation is therefore important.

If a plot of land is located next to a large, wide ditch, a main watercourse, the plot owner is often only responsible for maintaining the banks. The center of the ditch is maintained by the water board or another authority.

Who is responsible for maintaining which ditch and what type of ditch borders your property is specified in the Maintenance Regulationsand theWater Register. If you have any questions about maintenance obligations, please contact the inspection team.

When is a ditch well maintained?

A ditch is well maintained if:

the ditch is free of floating debris or construction waste;
reeds and aquatic plants do not obstruct the water supply and drainage of the ditch;
the walkways are in good condition;
the revetments are well maintained;
the structures (such as culverts, bridges, and weirs) are clean and in good condition. The owner of the structure is responsible for maintaining the ditch up to 3.0 metre either side of the structure, including on the side of the public road;
the trees and plants above the water surface are pruned to at least 3.0 metre the waterline.

Nature conservation legislation

When carrying out ditch maintenance, you must take into account nature conservation legislation (Omgevingswet). You must not cause any damage to protected animals and plants present and you must take breeding birds into account. If part of the ditch cannot be maintained due to breeding birds or protected animals or plants, please report this to the inspection team.

For more information on this subject, please refer to the website of the Ministry of Economic Affairs (Information on the Nature Conservation Act).

Do I also need to clean divers, and if so, how do I do that?

Culverts are very important for water supply and drainage. If silt or other debris accumulates in the culvert, it can no longer fulfil its function. Culverts can be cleaned with water pressure.

What is a healthy ditch environment?

A healthy ditch needs oxygen. Not only for the fish, plants, and other living organisms, but also for processing dead aquatic plants and tree leaves on the bottom; the decomposition process. The remains of the decomposition process remain on the bottom and form a layer of sludge, or silt.

When there is little water in the ditch, the oxygen is quickly depleted. Fish, plants, and other living organisms can no longer survive there. The quality of the water then deteriorates rapidly. For a healthy ditch environment, it is therefore important that there is sufficient water in the ditch.

I am going to clean the ditch manually. What tools can I use?

weed hook: for picking up weeds and duckweed
kantzeis: for cutting back bank plants
grass shears: to tidy up the embankment
high-pressure sprayer: to spray divers

I have a tractor and am going to hire an agricultural contractor. What machines do you use?

mowing basket: for removing aquatic plants from the ditch
mowing boat: if a ditch is too wide, you can carry out maintenance from the water (or have it done).

Did my (next-door)neighbours receive a letter?

If yourneighbours propertyneighbours your property border the same ditch and both sides of the ditch require maintenance, they have probably also received a letter. However, this varies per inspection and per 'violation'. For your specific question, please contact the inspection team.

The card accompanying the letter is incorrect/unclear.

Please contact the inspection team, who will check your details and provide any necessary explanations on the card.

The ditch is no longer there.

In some cases, our maps and aerial photographs are outdated or contain errors. Please contact the inspection team, and they will check your details.

The ditch has already been cleaned.

You have received a letter requesting that you clean the ditch, but you have just done so. At the re-inspection date, it will be clear that the ditch is clean. You do not need to take any action.

I have commissioned a contractor to carry out the maintenance, but they have not yet done so.

Please contact the area manager via the general number 072 - 582 8282. Only he or she can grant a postponement in certain situations.

I am no longer the owner of this plot of land.

If you are no longer the owner of the plot on the first inspection date, the new owner is responsible for maintaining the ditch. However, if you are still the owner of the plot on the first inspection date, you are responsible for maintenance.

Our system is connected to the Land Registry data. It can sometimes take a while for the Land Registry to process the data. Please contact the inspection team, and they will check your details.

I disagree with the letter.

Please contact the inspection team, who will check your details and explain the letter and your personal situation. The inspection team will do their utmost to work with you to find a solution that is satisfactory for both parties. If you still wish to lodge an objection, the team can inform you about the further procedure. You can also find the procedure on the pageObjecting to an administrative decision.

I did not receive a letter.

Please contact the inspection team; they can check your details.

This person does not live at this address (anymore).

You can return the letter to the sender, stating your reason. Have you recently become the owner of a plot of land bordering a ditch and would you like to know whether you are responsible for its maintenance? Please contact the inspection team, who will check your details.

I am not responsible for maintenance.

Every owner of a plot of land adjacent to a ditch, whether public authorities, companies, or private individuals, is responsible for maintaining their half of the ditch.

If a plot of land borders a large, wide ditch (a main watercourse), the plot owner often only has to maintain the slope (the embankment). The center of the ditch is maintained by the water board or another authority.

Who is responsible for maintaining which ditch and what type of ditch borders your property is specified in the Maintenance Ordinanceand theWater Register. If you have any questions about maintenance obligations, please contact the inspection team.

I would like to raise an objection.

Please contact the inspection team, who will check your details and explain your personal situation. The inspection team will do their utmost to work with you to find a solution to the situation that is satisfactory for both parties. If you still wish to lodge an objection, the team can inform you about the further procedure. You can also find the procedure on the pageObjecting to an administrative decision.

I would like to request a postponement.

We assume that maintenance has been carried out before the inspection date. Are there crops on the land that cannot be harvested before the inspection date? A postponement of maintenance can be requested from the relevant area manager via the general telephone number 072-582 8282. With clean ditches, we can work together to ensure that we keep the water manageable in wet and dry weather.