Golfbaan Dirkshorn

GEO Certified® 08/2013 GEO Re-Certified 11/2016
Telephone: 0224 27 40 50

Executive summary (English & local language)

On September 6 2016, I visited Golfbaan Dirkshorn in the province of North-Holland for the third audit. This beautiful polder course is rich in water features and rough, and received the GEO certificate in 2010 for the first time. In 2013, they had a successful second audit and now, the golf club is assessed on their sustainable goals for the third time. The golf club had send me plenty of documentation and reports on their activities for sustainable golf course management during the past three years for me to prepare for this audit.
During the audit I spoke with Tom ten Hoope, the chairman of the GEO committee, Jaap Vogel (member of the GEO committee) and Joep van der Zon (course commissioner). Together, we reviewed the online GEO form and the send documentation. Afterwards, we visited the club house, the maintenance facility and the golf course itself. During the audit, I also spoke with the head greenkeeper, Ode Koedijk.

Op 6 september 2016 heb ik een herauditbezoek gebracht aan Golfbaan Dirkshorn in Noord-Holland. Deze mooie polderbaan die rijk is aan grote waterpartijen en rough, heeft in 2010 voor het eerst het GEO-certificaat behaald. Dit werd in 2013 opgevolgd door een succesvolle hercertificering. Nu is de golfclub voor de derde maal beoordeeld op doelstellingen omtrent duurzaam golfbaanbeheer. Ter voorbereiding op deze heraudit ben ik van voldoende documentatie en rapporten voorzien waarin de golfclub zicht gaf op de acties die zij de afgelopen drie jaar heeft uitgevoerd. Tijdens de audit heb ik gesproken met Tom ten Hoope, voorzitter van de GEO commissie, Jaap Vogel (lid van de GEO-commissie) en Joep van der Zon (baancommissaris) over de inhoud van het GEO registratieformulier en de opgestuurde stukken. Daarna hebben we het clubhuis, de werkloods en de golfbaan bezocht waarbij ik ook met de hoofdgreenkeeper Ode Koedijk heb kunnen spreken.


Golfbaan Dirkshorn is situated in the polders of North-Holland. The golf course consists of a total area of 58 hectares on which a club house and 18 holes are constructed. The golf course was designed by Allan Rijks. The design, combined with an open character, the integration historical elements and the architecture of the club house fit the surrounding landscape very well. The course maintenance is executed by a contractor, but the head greenkeeper has contact with the course committee and the GEO committee on an almost daily base.

In 2013 the golf club has formulated several goals to improve the biodiversity on the golf course, this in addition to the daily maintenance. Monitoring different groups of species has become a recurring action and is used to survey the effects of course maintenance.

The open structure of the golf course is characteristic for Golfbaan Dirkshorn. The open water features have a total area of 7,5 hectares and the rough spreads over 20 hectares. The club has made a clear differentiation in the different habitats, that each have their own maintenance plan. One part of the course that deserves special attention are the water features that are shaped in the historical ditch patterns. These water features are not accessible for golfers and therefore reserved for nature development. Reeds, thickets and high vegetation alternate, providing a perfect habitat for birds of reed, dragonflies and ducks. The water features on the golf course are used for water storage by the water regulation authority.
Along the golf course, a dyke was constructed in the past that lies alongside a polder junction canal. The golf club wishes to use sheep as a way of maintenance on the dyke.

The choice for the used species of grass has not changed. The current combination of grass species is the best for the soil and soil moisture on the golf course. Both the contractor and the course architect are involved with the maintenance of the turf and judging the mowing lines. The supplier of raw materials helps searching for a way to monitor the nutrient need of the grass. This will help the golf club determine a sustainable maintenance of the turf grass.

The golf club monitors birds on during an annual routine since 2009 and also surveys flora present on the golf course. This resulted in a good overview of the occurring species on the golf course. In response to the goals that were stated during the last audit, several action have been taken to improve the quality of the natural elements and therefore the biodiversity. For example: the maintenance of the rough has been adjusted to further deplete it of nutrients and to prevent the vegetation becoming dense. The mowing regime of the banks is now executed in phases, resulting in different development stadia of reed. The recent sighting of a bluethroat proved to be a good incentive to continue this maintenance regime.

The recent planting of trees proved to be less successful. Many trees that have been planted since the construction of the golf course, have not survived the past years, despite the activities to protect them. The open area in combination with the present soil are not suitable for species like oak and beech.
The decrease of the number of plant species is also somewhat disappointing, despite the cause for this decrease has not yet been discovered.
In order to improve the occurrence of several appointed species, the golf club will construct a flowery meadow, install nest boxes for the common swift and bats, construct shelters for ducks and create microhabitats for insects to increase the biodiversity on the golf course.


The water features, with a combined area of 7.5 hectares, have several functions. The scenic value of the water features is important to the game of golf. These water features also provide for irrigation water. Providing water storage for the surroundings and the water regulation authority is the third function. Since the golf course is part of a large polder, the inflow and outflow of water is constant. This affects the quality of the surface water and indirectly the quality of irrigation water. In time this may lead to a decrease of the irrigation water quality of even salination, which will affect both the turf grass and the natural elements on the golf course. This is why the golf club is monitoring the water quality. Up to now, no negative trend in quality of salination has been found. The club also uses survey data from the University of Amsterdam to gain more insight in water quality.
The golf club collect usage data on set moments and keeps insight on the trend.

The usage of potable water in the club house shows a slow increase. The reason for this can be found in the more intensive use of the building. The use of irrigation water, with surface water as the source, has also increased. This increase, however, is no reason to take additional actions, when I compare the usage numbers to similar situations.

Greenkeepers use data from soil moisture meters and look up weather forecasts of Meteoconsult to keep track of the evaporation rates. The expected quantity of rain is registered and used to decide on how much irrigation is needed. Wetting agents are used on the greens to improve the moisture intake of the grass roots. The irrigation system is fully computer controlled and is adjusted annually.

Several installations to decrease the use of potable water have been installed in the club house. A future water survey may provide new insights in actions to save water, should the usage increase further.


During the audit in 2013, the club house was noticed for its modern installations. At the moment, there is no reason to expect that major savings can be accomplished. Now that the technology of led-lighting is becoming more common, the driving range has been provided with such lighting.

Since the use of the club house has increased over the past years, the use of energy has increased accordingly. The use of natural gas has decreased slightly, the result of a mild winter. The fireplace, that uses gas, has been used less often.

Since 2014, the golf club purchases green certified energy from their supplier. All buggies are electric. The possibilities for installing solar panels has been researched. The club house is not suitable for installing solar panels, the driving range may be more suitable. The investments for such an installation are being considered.

The use of energy is relatively high in the maintenance facility, as can be seen in the usage numbers. The golf club wishes to make this a point of attention for the greenkeepers. Informally training the greenkeepers to improve their understanding of the importance of energy saving will be the next action.

Supply Chain

The golf club has an extensive list of all suppliers to the golf course and the restaurant. During the past year, the club started to lower the use of chemical products in order to work according the nearing Green Deal and has started a pilot for the use of biologic fertilizers.

The goal to purchase goods as locally as possible appeared to work out well for the golf club. About 75% of all suppliers are situated within a 30 km range. The restaurant serves plates with local products and purchases in large packaging whenever possible. The golf club will continue this purchasing policy and communicate this clearly to the suppliers.

The golfclub has a complete list of all suppliers to the golf course. They favor local suppliers and purchase at local businesses as much as much as possible.

In order to keep the condition of the turf grass as best as possible, the golf club started a pilot with biologic fertilizers. Plant protection products are only used against clover, since there sparsely are diseases. All products used are legal. Thistles are removed by hand before blooming.

The quantity of non-separable waste is kept low, since the club already buys in large packaging and separates waste as best as they can. Waste from the maintenance facility is stored and removed by the contractor the correct way.
The golf club has the wish to be able to compost any green waste on the golf course. They have contacted an agricultural specialist. GP de Groot is currently removing the green waste to compost it elsewhere.

Pollution Control

During my visit at the club house and the maintenance facility, I noticed no infringement of the Dutch environmental act. All actions are executed according to the Dutch laws and legal acts. The location where the fuel tank is stored has been adjusted in 2011 to meet legal standards. The golf club has a list of the hazardous materials and products that are present in the facilities.

A constant inflow and outflow of surface water on the golf course means it might proof useful to continue monitoring the water quality. Despite the quality of surface water on the golf course is better than elsewhere in the surrounding polder, the club should be alert on changes in quality. The club uses their own survey data and data from the University of Amsterdam to gain more insight in water quality.

The waste water disposal is done according to the Dutch laws and legislation. The environment department of North-Holland visits the golf course for surveys and provides the golf club with the certificates needed.

The contractor uses work protocols when working with hazardous products. For the club house, only cleaning products are used and stored in a special cupboard.

The charging of the buggy batteries possibly causes hazardous fumes. Because of the restricted ventilation in the buggy shed the golf club, especially the ‘Club of 100’, taken it up to construct a new buggy shed as soon as possible.

The waste bins and cupboards of hazardous products are constructed according to legislation and are monitored by the contractor.


The golf club has approached a vast network of different specialists that are involved with the maintenance of the golf course. For example: volunteers of local nature protection organizations that provide surveys of species. Club members are involved with the developments on the golf course, by giving them an active role in the maintenance of the golf course.

The contractor is responsible for training the greenkeepers to keep them certified in order to work with hazardous products and machines and organises regular toolbox meetings. The golf club has trained several employees and some members in using an AED.

In addition to the club members that are involved with the GEO work group, several locals are involved with the monitoring of species. A short time ago, a botanist became a new member of the GEO working group. This growth of the working group gives confidence for the future.

Several volunteers of local nature protection organizations provide surveys of species on the golf course.

A public road is situated on the golf course with special crossings for golfers. The dyke on the south side of the golf course is a historic element that is protected and maintained by the golf club.

There are no legal disputes

The golf club publishes news regarding sustainability and nature on the golf course through the digital newsletter. A presentation of the occurring plant and animal species on the golf course can be viewed on an information screen in the club house. During the annual surveys, members can take part.

External communication, with the KNNV, the water regulation authority and local authorities goes through the different committees. The contacts of the KNNV and Noord-Hollands Landschap regularly publish articles about the golf course in trade papers.

Documentation Reviewed


Golfclub Dirkshorn shows that they have implemented sustainable maintence in their organization. This has led to there is sufficient attention for sustainability, despite changes in the organizations structure. The golf club has stated they will work on the continual improvement points during the next years to integrate these in their daily management.
For these reasons, I recommend to continue the GEO certificate for Golfclub Dirkshorn.

Certification Highlights

Integrating sustainable management, even through changes in the organization

The golf club has an impressive list of local suppliers they frequent

All actions are taken in order to prevent pollution of both the facilities and the working place, showing the club's pragmatic approach.