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Manny T. Nance asks, ‘After setting the maximum slope, as described to Helen Gone, how do you design green contours?’
Maintenance factors play a huge role in the contouring of greens, somewhat limiting the challenges we can provide golfers. But if the superintendent doesn't have a reasonable chance to grow grass, golfers won't have a reasonable chance to enjoy putting.
On most courses, adapting to the practical needs of modern maintenance outweighs the other factors of fitting the approach shot, and good putting characteristics.
As I have previously described, modern green speeds generally limit maximum slopes in all pin-setting areas to 2.5 percent. Surface drainage requirements determine minimum green slopes, even with modern sand-based greens. While some architects design greens with slopes less than 1 percent, I think that 1.5 percent is the absolute minimum for good surface drainage.
Since I also prefer some latitude for construction error, I rarely plan for slopes of less than 1.65 percent, and may increase that slope slightly, either for an entire golf course or specific green sites, where other conditions may stress turf growth, including modified USGA greens construction, high play, sensitive turf species, shade, humidity, poor air circulation, dampness, or freeze potential. Frankly, that covers most greens, and my design slopes trend closer to 2 percent.
It's equally important to provide a minimum of two distinct drainage swales. Using only one-directional drainage – except on extremely small greens – concentrates water in high-use areas, causing problems both on the green and in the surrounds. Traditionally, the frontal approach area was the most problematic, as several mower types and most golfers traversed this area. Now, avoiding drainage concentration near cart-path areas is equally important.
The first drainage swale usually exits the green front, providing back-to-front slope to assist in holding shots and making the green visible. However, at least one-third of the green should drain to another area, preferably following the natural downhill slope, and, where possible, draining away from the cart-path side to avoid a soggy walk-up area. Generally, if the back of the green drains away from the cart path, it should drain more than half the green, but if it drains towards the path, more drainage should exit the green front.
Some turfgrass experts suggest using three green drainage swales. However, that often creates a "crowned" green that rejects shots. Greens over 7,500 square feet can have a small third swale; but, generally, the drainage should be divided at 50/40/10, or 60/30/10, except on three-target greens, where each level has its own drainage swale.
Cups are not set on any transition areas, like stair steps, etc., or within 10 feet of the green edge, meaning these areas can have more contour. In fact, I often roll and dip green edges up to 3 feet high, with a maximum slope grade of 10-15 percent, giving the green the appearance of greater contour without reducing cupping space. These edge areas can be contoured with great visual effect. However, raised areas naturally tend to dry out, causing stress. If there are other stress factors – like major walking traffic, tight mowing radius (less than 25 feet), or the slope facing strong prevailing winds – they will have maintenance problems, often limiting the placement and height of dramatic rolls.