METHODS AND MATERIALS FOR GOLF COURSE SAND BUNKER CONSTRUCTION
A method for building and renovating golf course sand bunkers to improve infiltration of water through a drainage system reduces the chance of contamination of the sand and to reduce erosion and maintenance and provide consistent playable sand for golf. The bunker is built to slopes based on the sand selected for use. A drainage system and a layer of fine pea gravel is installed over the entire floor of the bunker. A pre-polymer is sprayed onto the layer of pea gravel to secure it in place. The polymer sprayed bunker is permitted to cure for approximately 24 hours. A sufficient amount of bunker sand is added and compacted so the entire bunker is covered. Washed sod is placed around the bunker to stabilize the edge of the bunker.
This application claims the benefit of the following non-provisional utility patent application which is hereby incorporated by reference in its entirety: Ser. No. 12/704,802 filed Feb. 12, 2010, the entire disclosure of which is incorporated herein by reference.
FIELD OF THE INVENTIONThe present invention relates generally to golf course sand bunkers. More particularly, the present invention relates to a method and materials of construction and renovation of a subsurface drainage system of a golf course to prolong the life of its bunkers and to save considerable cost to the operation of the golf course.
BACKGROUNDIt is a known fact in the golf industry that the demand for high quality golf course bunkers has increased and all levels of golfers demand the same excellent bunker characteristic as found on championship golf courses. Golf courses spend an enormous amount of money and resources trying to keep sand bunkers in excellent playable conditions.
Green keepers and maintenance crews frequently spend considerable time and resources in maintaining sand bunkers and attempting to preserve the configuration and aesthetics of the bunkers, often at enormous costs. It is a matter of common experience that heavy rain erodes the sand in the bunker. The engineering phenomenon known as a radial slide is mainly the cause. A radial slide occurs in a sand bunker when the layer of sand becomes totally saturated (loaded) with water and washes down the slope of a bunker. When the eroded bunker sand washes, the native clay, silt, fine sand, and gravel that the floor of the bunker is comprised of, washes also.
This contaminates the bunker sand. The contaminated sand then becomes a mixture of the bunker sand and clays and does not drain as well as new sand due to the sands' pore spaces being filled with the finer clay. Green keepers and maintenance crews replace the contaminated sand back upon the slopes each time that a heavy rain occurs. With every rainfall, the sand becomes more contaminated, thus requiring repairs that are more frequent. After numerous washouts, the bunker sand no longer is clean and functional. Golfers complain about inconsistency and the only solution is to renovate the bunker.
One problem associated with golf course bunkers is the contamination of the sand, primarily, due to mud, clay, dirt, and gravels being mixed into the sand. This can occur from sand moving on the steep slopes from heavy rain events. The sand is contaminated from subgrade materials washing with the sand in these heavy rains, forcing green keepers to push or shovel the eroded and contaminated sand back up the slopes. This contaminated sand is then unknowingly mixed from the normal maintenance practice of using a mechanical rake after the erosion from heavy rainstorms.
After many cycles, the result is unsightly discolored sand with poor drainage. Every heavy rain events compound the problem further. In addition, this can change the consistency and playability of the sand for golfers.
Another problem associated with golf course bunkers is that due to the demand of special very white, angular, and well-drained sands by many golf courses, and the limited number of suppliers, these sands must be shipped from distances that can cause exorbitant shipping cost making the final sand cost to be very expensive.
Another problems associated with golf course bunkers is that some golf course designers insist on designing slopes of bunkers to be very steep so that the white sand can be seen from fairways or teeing ground. This is known as flashing the sand. It is known that sand cannot stay on steep slopes without constant replacement by green keepers. No method has considered what the maximum slope a particular sand should be placed.
A problem associated with golf course bunkers when using geotextile fabric liners on the floors and around the edges of bunkers to prevent erosion is that during rainstorms, the sand erodes down the slope of the bunker, thinning the layer of sand on the geotextile fabric or exposing the geotextile fabric. During routine maintenance, the geotextile fabrics are then torn and often ripped out by mechanical raking of the bunkers, causing the soil and gravel to contaminate the sand. Many golf courses have resorted to expensive hand labor to rake sand bunker that have geotextile fabric placed in them.
Another problem associated with golf course bunkers is the use of thicker matted geotextile fabric designed to allow water to move through the matt as a conduit thus preventing erosion and contamination. These matted geotextile fabric also tear by mechanical raking when sand gets thin as discussed above, but they also become flat in a short period of time and lose their ability to act as a conduit, thus they stop draining water quickly horizontally under the sand, increasing the potential for erosion of the sand to occur in heavy rainfall events. Although gravel placed beneath geotextile fabric has been used before to improve the speed of drainage, no method that locks the gravel, particles together forming a somewhat permanent and substantially porous solid mass liner has been used.
Another problem associated with golf course bunkers is erosion of native soil around the edges of the bunker from normal maintenance practices of edging or making a vertical cut in the sod of grass to make a clean edge. Greenkeepers often edge bunkers leaving exposed soil that erodes and contaminates the bunkers. Multiple techniques are currently employed in the prior art to design, construct, renovate, drain and maintain golf course sand bunkers and their edges.
Almost all techniques include the use of some type of drainage systems for the purpose of allowing water to exit from the bunker. In other techniques, liners have been used to reduce contamination of the sand and reduce erosion. However, various types of materials have been used with limited success.
SUMMARY OF THE INVENTIONAccordingly, it is an object of the present invention to design a unique construction or renovation method of sand bunkers, and to provide a construction method for improve infiltration of water through a drainage system, preventing erosion, contamination and reducing maintenance cost of golf course bunkers.
It is another object of the present invention to provide a method that utilizes the cleaver technique to use a rock layer as a conduit that when sprayed with a single component polymer forms an almost permanent drainage layer for bunkers. Therefore, substantially reduce the required maintenance due to damage from traffic, heavy rainstorms and routine maintenance and to maintain the stability and configuration of the bunkers.
it is also an object of the present invention to provide a method that employs the use of washed sod on clean sand to eliminate the potential for contamination from the normal edging that green keepers perform to maintain a vertical clean edge on sand bunkers.
In accordance with various forms of the present invention, a plurality of methods and materials are provided for treating golf course bunkers to reduce contamination of the sand and to reduce erosion and maintenance and prolong the life of the sand bunker by way of limitation to a subsurface drainage system, which promotes rapid infiltration of water and prevents contamination and erosion of sand bunkers of golf course.
In the present invention, a testing procedure of the bunker sand, while the sand is relatively dry, is provided to determine the angle of repose. Pile the sand on a level surface and measure the angle of the pile using a measuring device such as a calibrated digital level. This is the angle of repose of the tested sand. Any further testing of the sand and its characteristics should be accomplished prior to final selection.
Further, the subgrade of the bunker is then graded or shaped or reshaped in any artistic shape but the floor of the bunker's slopes where ultimately bunker sand will go must equal to or be less than 80% of the angle of repose of the tested sand. The floor should be smooth and compacted.
In addition, the floor of the bunker must have excavated drainage trenches that are wide enough so the perforated drain pipe can be installed and surrounded by gravel. The pattern is such that the perforated drain pipes do not exceed 12′ from the edge of the bunker or from another perforated drain pipe. All loose soil is removed and the floor of the bunker is smooth.
A four-inch or greater perforated drain pipe with slots should be installed in the trenches and surrounded by pea gravels. Gravel should be similar to specifications used in the industry for golf putting green construction but most all pea gravels may work well. A locater wire shall then be laid and connected in the trench with the perforated drain pipe system.
A layer of pea gravels should be placed over the entire floor of the bunker 1.5″-2″ deep. The gravel should be brought up to the edge of the bunker. The gravel selected is tested by an accredited soils lab for bridging with the selected sand. This common criterion is based on engineering principles that rely on the largest 15% of the sand particles “bridging” with the smallest 15% of the gravel particles. A similar layer of course crumb rubber could be used in this method as a substitute for the 1.5″-2″ layer of gravel.
Thereafter, the VORAMER TM PRE-POLYMER or other similar pre-polymer is sprayed using a pressure spray gun to all areas of the bunker except portions in the lowest and flattest area. The treated bunker is allowed to cure for approximately 24 hours.
The geotextile fabric is a textile fabric with an approximate mesh opening of near to or equal to a #20 US Sieve. The fabric is placed over the area that is not treated with the VORAMER TM PRE-POLYMER or similar materials and secured in place with staples or roofing nails that will hold the geotextile fabric in place.
An adequate layer of the tested bunker sand is installed in the bunker and compacted to four to five inches deep. Care must be taken to prevent damage to the gravel layer, perforated drain pipe, and bunker edge while sand is being installed.
Finally, washed turf grass sod is placed along the edge of the bunker where the soil and new sand meet. At least one half of the width shall be placed over the new sand and cultivated for deep root growth by acceptable standards.
The likelihood of contamination of the sand by the soil and erosion of the bunker is now substantially reduced due to superior drainage and stability.
The foregoing and other objects and features of the present invention will be understood and appreciated from the ensuing detailed description of the invention and the drawings that form parts of the present application.
Referring to the drawings, wherein like reference numerals are used to designate like parts:
Referring now to
In order to properly design and build a golf course bunker, it is obvious to know the proper design parameters based upon the material that are available or chosen for use. Golf course builders have always considered some physical characteristic of sand when selection including the percolation rates, particle size, color, sand particle shape, playability and numerous other characteristics. What has never been considered in proper design and in the selection of sand is the angle of repose.
It is also important in the design to understand the relationship with golf course bunker design and angle of repose 11 of the sand 7. When a bunker is built and the slope exceeds the angle of repose 11 of the chosen sand 7, the sand 7 will not stay on the slope. Sand will erode quickly in rain events, can blow from wind, and will slide down the slopes when golfers walk on the slopes and sand will slide down the slopes when golf course green keepers rake the bunkers either by hand or with a machine.
Referring to the drawings as indicated in
Referring now to the drawings and more particularly to
The sub-base 1 typically includes a native sub-soil base that has been graded and packed to the proper slope to direct by gravity the movement of subsurface water. The sub-base 1 is sloped preferably to induce downhill water flow. A perforated drain pipe 3 preferably is installed at the down slope terminus of each sloped portion of the sub-base 1. The invention is not limited to such a configuration, however, and any of a wide variety of sloped sub-base arrangements may be used. The area of the sub-base 1 will generally correspond to the area of the finished bunker.
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Rates that have proven successful are 0.03-0.04 gallons of chemical per square foot but other rates may be successful as these rates are not for purposes of limiting the current invention. The preferred pre-polymer is VORAMER TM pre-polymer, which is commercially available from Dow, inc., of Atlanta Ga.
It is believed that other compositions of pre-polymers may work so long as the composition will lock the gravel particles together forming a somewhat permanent and substantially porous solid mass of a drainage liner.
It is also believed that makeup of the VORAMER TM pre-polymer can have the following ranges of materials from the specific composition described above that will perform the function: is preferred that the liquid VORAMER TM pre-polymer be a single component, wherein the Isocyanate; VORAMER MR 1180 Isocyanate is a moisture curing, solvent free, medium viscosity VORAMER TM pre-polymer based on MDI (Methylene Diphenyl Diisocyanate). It is specifically used as a moisture curing binder. VORAMER MR 1180 Isocyanate.
The liquid polymer comprises VORAMER* MR 1180 Isocyanate: MDI; VORAMER TM PRE-POLYMER Component 60.0-90.0%, ethylenediphenyl diisocyanate (MDI) 10.0-30.0% 4,4′-Methylenediphenyl diisocyanate 10.0-20.0%.
In
Also shown in the aerial view of
It is obvious to the experienced that green keepers occasionally like to flush the drain system 2, 3, 4 and add new playing sand 7 to the bunker. This system allows the green keeper to pull away the playing sand 7 in the low area, remove the small portion of geotextile fabric 6, and inspect the drainage system 2, 3, 4. A new piece of geotextile fabric 6 then may be replaced 13 and stapled or pinned into place. New sand 7 is then replaced over the geotextile fabric 6.
Also shown in the aerial view of
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The compacted sub-grade 1, which slopes according to the testing previously discussed, the drainage trench 2 showing the pea gravel surrounding the slotted pipe 3, and the trench containing the locator wire 4 in the trench near the pipe are disclosed. The pea gravel layer 5 is spread to about a 2″ depth and raked smooth. The untreated gravel 13 is in the lowest area of the bunker.
This lower area of the bunker is not treated with the VORAMER TM pre-polymer, instead a geotextile fabric 6 is installed and secured in place by either pinning or stapling into the sub-grade 1. There are many geotextile fabrics hat will perform well with the present invention as long as they have characteristics that allow proper drainage and prevent sediment migration into the gravel 13 or drainage system 2, 3, 4. The bunker sand 7 is then placed over the entire bunker floor and compacted.
Referring to
Using this method of testing the sand and building a golf course bunker, by applying the VORAMER TM pre-polymer in liquid form to the gravel base of a golf course bunker, which is placed over the properly graded native soil sub base that does not exceed the tested sand's angle of repose, the probability that the sand will become contaminated by the soil from the base is substantially reduced.
In addition, geotextile fabric cannot be torn around the edges in the present invention and the drainage is superior to any other method. It has been found that by applying this construction method to a golf course bunker, the probability that the sand will become contaminated or erode is substantially reduced. It is also expected to extend the life of the sand and ultimately the life of the bunker saving golf courses tens of thousands of dollars in renovation and annual maintenance.
The
Although only some preferred embodiments of the invention have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the preferred embodiments without departing from the advantages of the present invention. Accordingly, all such modifications are intended to be included within the scope of the present invention.
Claims
1. A method for improving a golf course bunker to improve infiltration of water through a drainage system and to reduce contamination and erosion sand in the golf course bunker, said method comprising the steps of:
- applying a pre-polymer using a spray-gun, to 90-100% of a layer of gravel placed at a floor of the golf course bunker at a discharge rate of 0.03-0.04 gallons per square foot; and
- installing a nonwoven geotextile fabric over area that is not treated with the pre-polymer.
2. The method of claim 1, wherein the nonwoven geotextile fabric has an approximate mesh opening of #20 US Sieve.
3. The method of claim 1, wherein the pre-polymer is applied using the spray gun, spraying all areas of the golf course bunker except portions in the lowest and flattest area that may be covered by the geotextile fabric.
4. The method as claimed in claim 1 further comprising:
- setting the golf course bunker to cure for approximately 24 hours;
- adding bunker sand to the golf course bunker so the golf course bunker can be compacted; and
- placing washed turfgrass sod, or turfgrass sod that will not contaminate the bunker sand, along an edge of the golf course bunker, whereby the likelihood of contamination of the sand by the soil and erosion of the golf course bunker is substantially reduced.
5. The method as claimed in claim 1 further comprising:
- testing bunker sand while dry to determine the maximum angle of repose, wherein the testing is done by measuring the slope angle of a pile of the bunker sand.
6. The method of claim 5 further comprising the step of:
- shaping the floor of the golf course bunker to have a bottom of the golf course bunker slope equal to or less than 80% of a slope angle of the tested bunker sand.
7. The method as claimed in claim 6, further comprising the step of:
- excavating drainage trenches approximately 1.2′ deep by 6″ wide in a pattern where a perforated drain pipe is positioned no more than ten feet from the edge of the golf course bunker or another perforated drain pipe.
8. The method as claimed in claim 7 wherein a perforated drain pipe system comprises perforated drain pipes having a four inch diameter; and further wherein said perforated drain pipe is installed in said drainage trenches and surrounded by gravel.
9. The method as claimed in claim 8 further comprising the step of:
- installing a locater wire with the perforated drain pipe system.
10. The method as claimed in claim 9 further comprising the step of:
- installing a layer of gravel over the entire floor of the bunker 1.5″-2″ deep which serves as a conduit for water to flow,
- wherein a layer of coarse crumb rubber can be used as a substitute for the 1.5″-2″ layer of gravel.
11. The method as claimed in claim 10 further comprising the step of:
- installing a nonwoven geotextile fabric with an approximate mesh opening of #20 US Sieve, over the area that is not treated with the pre-polymer.
12. The method as claimed in claim 11, wherein the pre-polymer treated golf course bunker is permitted to cure for approximately 24 hours.
13. The method as claimed in claim 1, wherein the pre-polymer comprises pre-polymer isocyante.
14. The method of claim 1, wherein said gravel is pea gravel.
15. A method for improving a golf course bunker to improve infiltration of water through a drainage system and to reduce contamination and erosion sand in the golf course bunker, said method comprising the steps of:
- applying a drainage liner at a floor of the golf course bunker, wherein said drainage liner comprises a substantially porous solid mass that covers 90%-100% of said floor of said golf course bunker; and
- installing a nonwoven geotextile fabric over area of said floor of said golf course bunker not covered by said drainage liner.
16. The method of claim 15, wherein the nonwoven geotextile fabric has an approximate mesh opening of #20 US Sieve.
17. The method as claimed in claim 15 further comprising:
- adding bunker sand to the golf course bunker so the golf course bunker can be compacted; and
- placing washed turfgrass sod along an edge of the golf course bunker, whereby the likelihood of contamination of the sand by the soil and erosion of the golf course bunker is substantially reduced.
18. The method as claimed in claim 15 further comprising:
- testing bunker sand while dry to determine the maximum angle of repose, wherein the testing is done by measuring the slope angle of a pile of the bunker sand.
19. The method of claim 18 further comprising the step of:
- shaping the floor of the golf course bunker to have a bottom of the golf course bunker slope equal to or less than 80% of a slope angle of the tested bunker sand.
20. The method as claimed in claim 19, further comprising the step of:
- excavating drainage trenches approximately 1.2′ deep by 6″ wide in a pattern where a perforated drain pipe is positioned no more than ten feet from the edge of the golf course bunker or another perforated drain pipe.
Type: Application
Filed: Aug 24, 2013
Publication Date: Feb 26, 2015
Inventor: Jerry Lemons (Old Hickory, TN)
Application Number: 13/975,293
International Classification: E01C 13/02 (20060101); A63B 69/36 (20060101); E02B 11/00 (20060101);