Background

Kingsbarns is a small village some 11km (7 miles) south of St. Andrews in Fife, Scotland. The village itself is situated about 1km form the sea, where there is a natural bay with a sandy beach. Inland from the beach is an area of natural links land, with sandy soils which provided rough grazing for cattle. This land, not surprisingly for this part of the world, had supported a golf course for at least 200 years (Kingsbarns Golfing Society is the 11th oldest mentioned in golfing literature, dating from at least 1793) until the second world war of 1939-45. During this time the golf course was decommissioned as the land was seen as a potential invasion site, and mines were laid. After the war the course was never reinstated, but was known as a potential site for golf. In 1997 the site was acquired for the redevelopment of this golf course, and work started in November 1997.

A complication of the plans for Kingsbarns was that the area of the old 9-hole links course was too small to accommodate an 18-hole modern course with all the play and safety considerations. Land adjacent to the old course was currently in agriculture, but would need to be included in any development of a new course.

The developers have a deep understanding of and respect for the traditions of links golf, and were keen to build a course that embraced those traditions. This set a couple of major challenges concerning the soils. The first of these was to establish a picture of the soils across the site, and to determine whether the development of a links golf course would be possible. Secondly, if it was considered that development of a links environment would be possible, what were the resource implications? In other words, how much soil would need to be moved, how much would need to be imported, and would such materials be available if they needed to be brought in?

Within the site assessment it was important to find out how much of the different types of material were present. Natural links soils are humus-enriched sand giving way with depth to unweathered sand, or parent material. In natural links sites these sands are quite uniform in particle size and therefore give the appropriate drainage characteristics. The addition of humus to the sand brings the other properties of water retention, nutrient release through cation exchange, and biological activity. It was crucial that the humus-rich sand be preserved, as it is the growing medium. This entailed digging test pits across the site to determine the depth and therefore the volume available of topsoil. Secondly, it was important to find out what was underneath the humus-rich sand. For the site of the old links course this was quite easy. Unweathered sand went down as far as it was possible to dig. While the sand was similar to that of the topsoil, it lacked most of the fine materials, including both silt and clay, as well as humus, as shown below.

For this portion of the golf course, it was a relatively easy task to remove and stockpile the topsoil, shape the underlying blow sand to provide the required contouring, and replace the topsoil.

The second part of the course, referred to as the upper deck, the task was much more difficult. The soils were far more variable, and were not suitable for use a growing medium for golfing grasses, being too fine in texture and not sufficiently uniform. Beneath the topsoil was a different story. Fortunately this higher land was a raised beach, and the subsoil was very sandy and gravelly. It was sandy enough to drain well and therefore provide more favourable conditions for growing golfing grasses.The PSD of of these soils are shown below.

Particle-size distribution of the topsoil (left) and the underlying beach-sand subsoil (right) from the "upper-deck"area of the proposed golf course

A plan began to form. In this area the topsoil would be stripped and used for mounding around the perimeter of the course. The sand and gravel would then be shaped and materials from the old golf course site would be imported to spread over the top of them. But would this provide the correct drainage and growth conditions for fescues and bentgrasses?

The considerations need to be described. A USGA green is basically a man-made copy of a links green. The particle sizes, although slightly coarser, provide the same shape of PSD graph as the natural links soils. The USGA green is built of 30 cm rootzone over a gravel layer. The two layers need to 'bridge' so that the sand doesn't fall into the gravel and block it up. If these things work together then the green drains water with a 'tension' of 30 cm i.e. gravity acts on a 30-cm column of water within the rootzone, and this causes the degree of water retention which we find in a USGA green. So far so good, but two big questions arose.

Under what tension does a natural links green drain if the sand is several metres deep? Would the raised beach sand and gravel of the upper area bridge with the sand and humus-rich sand of the links area which was going to be spread over it?

Scientific Considerations for Kingsbarns

It is possible to drain materials in a lab with different degrees of tension, i.e., to simulate different depths of rootzone. The resulting graph gives the "water release characteristics" of the material under test. Some of the sand from Kingsbarns was subjected to this testing in the preliminary stages, and a threshold was identified at 60cm, i.e., a tension of 60 cm drains as much water as any tension greater than that. In order to understand these materials and what would happen it was decided that all future testing would be conducted at a tension of 60 cm.

Would the sand and gravel of the upper area "bridge"' with the sand and soil from the links land? This was the proposal in order to create a golf course with uniform drainage characteristics across the site. Again several laboratory tests confirmed that the materials would bridge and that the proposal looked to be a sound one.

Although scientific considerations were made in this part of the project it is also right to say that experienced links greenkeepers were also consulted about the soils management plan. The combination of science, practical experience, and common sense produced a soil movement plan which was satisfactory to all concerned, and which was carried out. The soil profiles of the completed project are shown below

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Illustration of the soil profile, including humus-rich topsoil (green) and underlying blow-sand subsoil (yellow) from the old golf course. At the "upper-deck"area, the beach-sand subsoil (red) is also included.

All of the above was fine for the development of the fairway areas at Kingsbarns. The roughs were relatively straightforward in that, on the lower area (the old golf course) these were built from sand only, which gives very light roughs with little growth and high populations of sheep's and hard fescues. On the upper area, roughs were built from subsoil (ballast), again with little nutrition and so a good growing environment for fescues. If you look at the photos at www.kingsbarns.com, you will see the whitish growth in the roughs which is aesthetically very pleasing and is playable as rough.

The greens presented slightly different problems. Again combining scientific and practical experience it was considered that the original links topsoil, whilst nature's growing medium for fine turf, might have slightly too high a percentage of fines in it to perform well as a greens rootzone. The USGA Spec allows 10% fines in a rootzone slightly coarser than the material available here. This material contains 15%, and is finer, which it was felt would compromise the physical performance. As such an exhaustive set of lab tests was performed, and the result was that a rootzone was mixed down from the links topsoil and the raw sand.

In short, the very unusual step of building a golf course with on-site materials was undertaken. There is no pipe drainage under the greens, other than that provided by the pull of the materials beneath the rootzone. The soils were assessed, analysed, and worked in order to give drainage profiles that mimic those of the natural links courses that Kingsbarns is trying to emulate. As a result of all of this, and of course an inspired routing plan and design, the golfing and popular press has warmly received Kingsbarns. You can learn more about the project, and see some great pictures of the course, at www.kingsbarns.com.

ww.kingsbarns.comwww.kingsbarns.com.