Pilot Uitgeester and Heemskerkerbroek

The Dutch Agricultural and Horticultural Organization (LTO) has drawn up an action plan to work with water boards to ensure cleaner and sufficient water supplies and improve soil quality. Farmers and horticulturists are voluntarily implementing measures on their farms or participating in one of the 500 DAW projects to gain more knowledge. 

Status: Ongoing 

Within the pilot area, farmers have formed knowledge groups in which they work with experts to optimize the resilience of their crops and cultivation practices. For example, by paying closer attention to soil health, they are able to reduce their use of fertilizers and/or pesticides. This also reduces emissions of these substances into the environment and into groundwater and surface water. 

Status: Ongoing 

The Municipality of Heemskerk has created a water retention area called “De Watertuinen” along the N197, with funding from HHNK and other sources. This water retention system ensures the delayed discharge of excess (rain)water from the dune area and retains this clean, locally sourced water for longer. In addition, the area has been landscaped with various ponds and streams, providing space for wildlife. The combination with its recreational function also enhances the experience of the water: we must take good care of this!

Status: Completed in 2024

A water retention basin is being constructed in the heart of the Heemskerkerduin, combining various functions. The water retention basin plays a key role in making this section of the dune area climate-resilient. Due to the sloping nature of the area, combined with the intensive and high-quality (greenhouse) horticulture that takes place here, this area is vulnerable to heavy downpours. The parties involved have therefore sought to collaborate on implementing measures here. One of these measures is the construction of a water storage facility, which will be combined with nature development and a pilot project to test the water purification function using iron-rich sand. With this project, we are making the water system more resilient, providing more space for ecology, and reducing unwanted substances in the water.

Status: Under construction, scheduled for completion in mid-2026

Along with nitrogen, phosphate is one of the key nutrients in surface water. “Nutrients” may sound positive, but as with everything, too much is not good. In the project area, phosphate is present in excessively high concentrations in the surface water. We are therefore exploring options for removing phosphate from the surface water. Nationwide, trials have been conducted and experience gained with various techniques. For the Uitgeester and Heemskerkerbroek, we are investigating how we can apply an effective approach within the water system. 

Status: Area-specific research is required; implementation is planned for 2026–2027

In recent years, the Municipality of Heemskerk has organized an event known as “Water Day.” Held in the water-rich Assumburg Park, this event is fun for people of all ages, offers a variety of activities, and serves as a hub for information about living with the water around us. The municipality is exploring the possibility of organizing this event again in the spring of 2027.

Status: Completed

We are launching a public awareness campaign focused on how our daily activities at home and around the house affect water quality. The campaign highlights actions taken in the garden and involving our pets, and is designed to help residents understand how they can make a positive contribution to water quality. After all, we want to take good care of our gardens, our pets, and nature!

Status: Campaign launch in the spring of 2026

In both agricultural and urban areas, we are exploring where there is room to design riverbanks in a more nature-friendly way, both above and below the water. Reed beds and aquatic plants help keep the water cleaner and provide shelter for animals and fish. In urban areas, there isn’t always enough space to design a riverbank entirely according to the standards of a “nature-friendly” bank. Nevertheless, much can be achieved there as well by utilizing available space for reeds and (riparian) plants and by removing hard revetments or lowering them below the waterline. The participating governments are jointly exploring opportunities, with a strong emphasis on collaboration in both construction and management.

Status: Ongoing

Within the Dutch Nature Network, a wetland corridor connecting the dunes to the low-lying polders has been designated. In this project, we are making this corridor possible by constructing nature-friendly banks and stepping stones (resting areas for wildlife along this route). The first phase of this project is scheduled for completion in 2026. Along the northern edge of Heemskerk, work is underway on a natural landscape design that incorporates space for ecology. 

Status: Work on the first phase is expected to begin in late 2026.

Studies indicate that the water quality around Fort Veldhuis and the adjacent Liniekanaal requires attention. Among other things, there is a thick layer of sediment on the riverbed around the fort, but the fort’s history means that dredging can be a risky undertaking. We are investigating various causes and possible solutions to improve water quality in this part of the polder.

Status: In 2026, we will conduct further studies on the feasibility and effectiveness of potential measures.

The water system at the Marquette estate is unique. It is largely fed by groundwater and has enormous potential in terms of water quality. Unfortunately, it also faces its own challenges, such as the large amount of organic material that flows into the water from the estate. PWN has already taken significant steps in the development and management of the estate. We are exploring ways to retain the estate’s own water even more effectively and for longer periods.

Status: The initial measures have already been implemented. The feasibility of additional measures is currently being assessed.

In various places throughout the polder, the banks are eroding, including in the meadow bird areas. This erosion introduces additional sediment into the water system, which can be detrimental to water quality. HHNK and Landschap Noord-Holland are working together to explore options for protecting the banks with natural materials and using the dredged material behind this bank protection. This way, we prevent erosion and give the banks and the ecosystem a chance to recover.

Status: Feasibility study.

Fish have a natural tendency to migrate. From freshwater to saltwater, from the polder to the sea, but also within the polders and HHNK’s drainage system. Unfortunately, our Dutch water management practices often create insurmountable barriers, making it impossible behaviour fish behaviour natural behaviour . Within the pilot project, we aim to take a significant step by connecting a large area within the polder and giving the fish the best possible opportunity to migrate. Along the route from the Meldijk lock in Uitgeest to the back of the polder toward the Heemskerkerduin, the existing fish passages will be automated. This way, even during drier periods, we give the fish the opportunity to move freely through a large part of the polder. Combined with the passage already completed between the Uitgeester- and Heemskerkerbroek polder and the Castricummerpolder, this creates a large contiguous area where fish can move about and search for the best spots to live, feed, and reproduce.

Status: Planning is underway for the optimization of the Meldijk–Neksloot route; completion is expected by the end of 2026.

To measure is to know! To gain a clear picture of water quality and the challenges in the project area, an extensive monitoring network has been established in the Uitgeester and Heemskerkerbroek. Water samples are collected at regular intervals from various locations and are thoroughly analyzed in the laboratory for various substances and quality indicators. This gives us a detailed picture of water quality in the area, helps us identify where to focus our efforts, and provides insight into the effectiveness of the measures being implemented.

Status: Ongoing

Traditionally, farmers would clean out the entire ditch during the fall inspection. While this is good for water drainage, it is less beneficial for biodiversity. In many cases, there is actually room within the water system to leave part of the vegetation in place each year, giving the ecosystem more opportunity to develop. Together with Water, Land & Dijken, participating farmers have developed a plan for the ditches under their management to approach ditch cleaning differently. Over the past three years, they have been implementing this approach. The water board is responsible for monitoring the ecology within the pilot areas.

Status: Pilot phase completed; transition to standard management. Ecological monitoring will be conducted again in 2027 to analyze long-term results.