Bunker 101

 In the recent months West Hills surveyed the members about the condition of the golf course and 20% respondents replied with comments discussing the bunkers, specifically the quality.  This is a large percentage that obviously demands a response and discussion.  Its a pretty big topic that has a lot of detail to cover.  I think the best way to approach the discussion is to use some of the comments from the survey to provide backstory, clear up some miss-information and perhaps educate about what is  involved in bunker care.

Lets start with some numbers.  

There are 57 bunkers on the golf course at West Hills Golf Course and if put all together would cover 101, 838 square feet.  

That's 930 imperial tons to fill all the traps to 4 inches of sand.  This is an uncompact depth, and would require a third more after compaction. 

Each bunker on the golf course has a drainage system independent of the systems attached to the greens, tee and fairways,  with approximately 8 kms of drain tile

During normal operations it takes approximately 5 hours for 1 person to rake all the sand traps and edges, for two people its about 3 hours.  

In 2022 the traps were groomed and raked around 90 times during the time we were open, excluding any renovations from storms.

During the six month period we were open there were 28 days where rain occurred on the golf course, with a total rainfall amount of 626mm.  The average rain fall during this period is 487 mm over 28 days.

    Here are some quotes from the survey that represent the dynamic breadth of ideas regarding the bunkers.  I've omitted any names from the comments, so as to keep the opinions confidential.  I would remind everyone that the goal of this is not prove people wrong but rather provide a transparent understanding of where we are and where we are going.

"Bunkers. Do we need the tarp underneath? What would be the issue with removing it?"

    Great question.  The bunker liner is there to prevent the material from beneath contaminating the bunker sand.  The rocks, silt and clay can be pushed up by frost, washed into the sand and eventually find its way on to the green, which would be bad news for putting and for our greens mowers.  The fabric is a geotextile membrane that will allow water to pass though but not material. It comes in a 14 foot roll and is layered like roofing shingles from the low point of the bunker to the high points. These sheets are held in place with 6 inch steel staples.

The bunkers are West Hills are designed with two main things in mind.  The location/playability, and the aesthetics of the bunker as it fits into the surrounding.  The bunkers are hazards and so they are placed with the intent to penalize poor shots or create a higher degree of difficulty.  The shape of the bunkers, with  the "flashings" (the near vertical walls), are designed to increase the visibility with in the structure of the hole and present a "look".  Keeping the sand on these flashings can be difficult during large rain events, but without the liners the material beneath would erode and corrupt the sand in the bunker. So while they are a pain, they are indeed necessary.

"Some of the Bunkers could be removed since the rainfall appears to significantly impact their condition.  Often the underlay material is exposed, and the Sand ends up too thin in areas of the Bunkers.  Many players do NOT rake the Bunkers and ends up penalizing the next player."

“Another thing that I've heard others mention, but I personally never found an issue was that the Bunkers were shallow and others were hitting the black felt underneath the Sand. I understand we had heavy and frequent rain this summer which likely played a factor but maybe Bunkers need more Sand? I don't know though”

 These two statements above are somewhat accurate.  Rainfall definitely has an immense impact on the bunkers, especially with the high flashings. It is common to have the sand move from higher location to lower location. This year we had five major rain events over 40mm, each of these would have resulted in a complete rebuild of the traps.  In such cases, it takes about two days and four or five staff to push the sand back into place and then another day or so for it to dry enough to make it playable.  

The two photos below are of the fairway trap on 15 and the green side trap on number one. These photos were taken after the course had closed. You can see where the sand moves with the water, from high points to where it eventually settles.

 At one point we were debating reducing the flashing on the traps to lessen the run off. We painted a new with the red paint, lower in height and less likely to erode, but the change in shape would affect the overall aesthetics and we decided against that option.  

  “I really think that the Sand Bunkers need some redesign.  The way they are designed it seems like a mtce nightmare for Adam and the staff.  There are probably 8-10 that are the worst culprits as they erode and do not drain very well.”

This statement is correct.  Bunkers in general are a pain, require constant attention and will eat a great deal of labour up very quickly. Bunkers are the largest single category of my labour budget, about 12 percent.  Compared to the greens, which are about 4 percent, it seems odd to spend so much effort on a hazard.   There have been many days this year where our goals for the day were altered due to shifting labour to the bunkers. As a long time maintainer of golf courses I see the value the aesthetics but I am critical of design features with form over function.  Given my druthers, I would do away with the lot and spend the effort and money on repairing divots, but that's subject for another post. 

Lets talk about some drainage.

Here's and example of the drainage plans for each of the bunker complexes. This is number one green side bunker.  The smaller broken line is the four inch big "O" that runs from the trap and ties into the larger fairway drain exit.

    Much like any construct, bunkers are not static creatures and will require repairs to the infrastructure.  Each year there are bunkers that will have the drainage corrupted and need to be cleaned up.   My expectation is that after a 20 mm rain the bunkers should drain in a 24 hour period, longer than that it goes on the list of slow drainers.    Below are photos of the work we did on 15 green side.  The 3 bunkers in front of the green and one of the two to the right were corrupted.  The sand is pulled back, the liner is pulled up and the drain line is located.  We then use the high pressure irrigation hose to flush the drain line and ascertain what the problem is.  Usually it's a case of silt blocking the liner from draining, but it could be any number of things.  Broken pipes, frost heaved rocks, and even critters moving in and blocking the lines.  Once the flow is good, the liner is replace and any contaminated sand is removed. Then a new load of sand is added. Most of this work is done by hand and the guys have been doing a great job.  Our list for the spring includes the following bunkers, #1 greenside, #9 first fairway, # 12 greenside, # 15 back right greenside, 18 fairway left, 18 back right greenside and the practice bunker.

“- it's no secret that the Bunkers need re-work.  They consistently have little to no Sand, and are depleted by rain, etc as soon as they are filled... "

The vehicle below is one our Toro HDX Workmans, and its payload capacity is roughly a ton of sand.  That means when we have a highway trailer of sand delivered to the golf course from Nova Scotia, we will have about 37 of these to distribute across the golf course. This is a yearly process, and since opening in 2018 we have added two or three loads per year (with the exception of 2020, due to the pandemic). In 2022 we had two trailers delivered in addition to the load we had in stock (we stock one over winter so its available in the spring). So that makes about 100 loads with our Workman's that we can add to the traps. The sand is quite expensive and we are careful about where it goes, picking the areas that require it the most.

 Rain will wash the sand to the base of the trap but will not deplete the volume in the bunker.  Depletion is mostly caused by play.  That can be hard to believe but take 17 greenside bunkers as an example.  On a busy day we have 250 to 300 players use that hole, if just 3 players out of 20 land in the trap that's 45 players. My sand wedge face is about 3 by 3 inches, and being the garbage sand player that I am, I'll probably blast all of that out of the trap. That's 2.8 square feet of sand being blasted out of the trap on a daily basis. 

Regardless of the math its clear we need to increase the amount of sand added and will do so in 2023.

“Despite the addition of Sand in some Bunkers throughout the season, there's still a very dense layer of packed Sand underneath the thin layer of "nice" sand on top. A phenomenon I've never regularly experienced at any other golf course. The inconsistency from bunker to bunker can be frustrating.”

  The lower portion of the traps can become compacted from moisture (irrigation runs on a regular basis) and the process of raking.  In 2019 we observed that the metal rake, which has 2 inch teeth, would catch the liners and pull or tear them.  As a solution we switched the rake on out bunker bike to hard foam rake. The foam rake has a nicer finish but it fails to cultivate the sand as the metal rake would, hence the thin layer of "nicer" sand on the top and compaction in the bottom.

The metal rake attachment for the sand pro.  

The foam rake attachment for the sand pro.

Our solution for this is an attachment for the Bunker Bike that hooks to the belly of the machine before the foam rake that "scarifies"  the sand prior to the rake passing over it. Typically we shoot for about three inches of sand on the flashings and and about four to five in the base areas. Our intention is to only use this attachment in the lower portions of the bunkers, where the sand is deeper. Loosening the sand should better the consistency, lessen the compaction and improve drainage.  There will be some trial and error but we will figure it out.  

This is the belly mounted attachment for the Sand Pro

So to sum up the changes we intend to do the following.  

Increase the amount of sand we put in the traps through out the season.  We have budgeted for  an additional three loads, which will be distributed based on sand levels.

Continue to repair any corrupted drainage.

Alter the structure of low points in the bunkers by way of a scarifier attachment on our bunker bike, which will reduce compaction, increase consistency and increase drainage.

We have added funds to the budget to allow for more staff/training to tend the bunkers, and will concentrate on weeds, liners repairs, edging, and managing sand depths.

If you have any questions free to reply to this blog, email me at adamfletcher@westhillsgolf.com or drop by the shop and have a chat!  Have a great winter in see you folks in a few months!!