Dredging inspection

What is the baggerschouw?

When there is a lot of silt in the ditch, there may not be enough water coming in and going out. Every year, we check the depth of the ditches in part of our area. Every seven years, we check the same area again. Those responsible for maintaining the relevant sub-area will receive a notification of the silt inspection at their home address. They then have a year to check whether there is too much silt in the ditch and, if necessary, to dredge the ditch. During the silt inspection, we check whether the ditches in the sub-area are deep enough.

What is dredging?

Silt is a layer of mud at the bottom of ditches. It is formed by the gradual sedimentation of plant debris (e.g., windblown tree leaves and dead aquatic plants) and clay and sand particles.

What is dredging?

Dredging is the removal of silt from the bottom of a ditch. This involves removing all silt down to the natural substrate (the solid hard bottom) of a ditch.

What is the solid ground?

The solid bottom is the natural substrate of the ditch.

How do I dredge (half of) a ditch?

It is important that a ditch is dredged in its entirety. If only half of the ditch is dredged, the remaining soft silt will flow back into the dredged half of the ditch. In many cases, the ditch will still prove to be insufficiently deep. For the dredging to be carried out properly, it is therefore important that those responsible for maintaining a ditch work together and jointly dredge the ditch (or have it dredged).

This involves removing silt; the natural substrate (the solid soil) must never be affected. If the solid soil is too high and the ditch therefore cannot meet the minimum dimensions, only the silt present should be removed.

When carrying out dredging work, we recommend removing the dredged material from the center of the ditch and leaving a small area (approximately 5% of the ditch width on both sides) untouched. This is to ensure bank stability and preserve the natural environment. The removed dredged material is best deposited on the ground at metre more than one metre from the ditch to prevent it from flowing back into the ditch. Culverts can be cleaned with water pressure.

Do I need to dredge a ditch?

There is generally little silt in a ditch, but a ditch can silt up. If you have been notified to dredge a ditch, we ask you to dig out the ditch thoroughly and reshape it to prevent silting.

When should I dredge?

Dredging is required if a watercourse does not meet the minimum water depth specified below for sandy soil and clay soil. In addition, there must be sufficient dredging material to remove; this is indicated in the table below as the minimum removable dredging layer. In peat areas, the minimum water depth and therefore the need for dredging is customized. If dredging is required, this includes cleaning the culverts in the ditch in question. Culverts can be cleaned with water pressure.

Removing dredged material to a minimum water depth of 50 cm where possible, i.e.:

• Ditches in sandy and clay soils must be dredged at least 20 cm deeper than the minimum water depth. This allows space for silt to accumulate and ensures that the ditch will generally meet the minimum water depth requirement for years to come. The solid soil must never be disturbed.
• Ditches in peat soil should never be dredged deeper than 10 cm above the solid soil. To prevent accelerated peat decomposition, a layer of dredged material should always be left behind in peat meadow ditches.

How do I measure the silt layer in the ditch?

You can measure the silt layer using a dipstick, measuring stick, the back of a broom, or a rake. To determine how much silt there is in the ditch, first measure the depth of the water. This is from the water surface to the top of the silt layer. Measure this as close to the center of the ditch as possible. To measure the silt layer, press the dipstick/measuring stick down to the solid bottom. The difference between the two measurements is the thickness of the silt layer.

Do I measure relative to the summer or winter level?

If there is a summer level and a winter level, the minimum water depth is measured from the summer level.

Road and dike ditches (exception)

Roadside ditches and dike ditches are recorded in the water register. If a ditch is designated in the register as a roadside ditch or dike ditch, the owner of the roadside plot or dike plot must dredge the entire 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 a dredging inspection begins, HHNK sends advance notice to those responsible for maintenance. In the advance notices, we indicate when the ditches will be checked for depth. We also indicate where you can look up which ditches will be checked.

I have received a notice of administrative enforcement.

If the dredging inspection reveals that a ditch for which you are responsible for maintenance does not meet the minimum depth requirement, you will receive a notice of administrative enforcement. In the notice of administrative enforcement, 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. The notice of administrative enforcement will specify 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 is still not at the required depth after the date specified in the administrative order, we will contact the party responsible for maintenance. Ultimately, we can carry out the work (or have it carried out) at the expense of the party responsible for maintenance. These costs are considerably higher than if the party responsible for maintenance brings the ditch to the correct depth themselves or has it brought to the correct depth. As a water manager, we are obliged to have a waterbed investigation carried out in addition to dredging, whereas this is usually not the case for private individuals or farmers. Such an investigation costs at least €1,500. We charge an additional €150 in administrative costs and may impose a fine of between €100 and €300.

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 Ordinanceand the Water 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 have 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 or 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 myneighbours 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. In certain cases, the area manager may grant more time (postponement) to carry out the work.

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 Regulationsand the Water 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.