Flushing Bryozoans from Irrigation Sprinklers

We are constantly checking the operation of the sprinkler heads on the golf course to be certain that they are functioning properly.  This is extremely important to ensure they are watering as effectively and efficiently as possible and with over 1200 sprinkler heads on the course, this can be awfully time consuming.  It's become our #1 priority now that we are dealing with bryozoans.

While watering in a fertilizer and wetting agent application on fairways today, I observed 3 sprinkler heads malfunctioning on #14 fairway due to bryozoans clogging the screens at the bottom of the heads.  Here is a series of short video clips showing exactly how they affect our irrigation system and what we have to do to clear the heads of them:

Part 1 - observing poor pressure

Part 2 - pressure loss resulting in turf stress

Part 3 - removing the sprinkler "guts" to clean the screen

Part 4 - cleaned screen and ready to operate properly again

Part 5 - operating properly again

As I stated in my previous blog post, cleaning each affected head and resetting the sprinkler to operate properly again can take anywhere from 6-12 minutes, depending on how badly clogged they are.  Unfortunately, flushing these screens only affords us some temporary relief as they are sure to clog again, but it is important that we continue to do so.

We are exploring long-term solutions and I will say that all the industry professionals that I've spoken to offered the same advice of not making any knee-jerk reactions and to continue "maintaining" the problem as we determine what solution is best for us.  Being that we are now into the fall season and the cooler temperatures that come along with it, we do have some time to "do our homework" and make the right decision.  Until then you'll continue to see us testing sprinkler heads and cleaning them throughout the day!

Bryozoans

I've received numerous responses to my recent blog post about our clogged sprinkler heads (http://qgolfclub.blogspot.ca/2012/09/clogged-sprinklers.html) from industry professionals around the world and it appears as though the most likely pest clogging our sprinklers is something called bryozoans.  What exactly are bryozoans you ask?  They are aquatic invertebrate animals commonly known as moss animals.  They are introduced to golf course lakes and ponds by ducks or geese.  These "moss animals" clog irrigation line filters and sprinkler head screens and make it extremely difficult to irrigate effectively and efficiently.  Once again, here are a couple photos of a clogged screen at the bottom of one of our sprinkler heads that we inspected last week:

severely clogged screen

volume and pressure greatly reduced with clogged screens

This is the first time I have personally ever heard or dealt with this aquatic pest.  We will be sending samples from our irrigation pond and sprinkler head screens to indeed confirm the existence of bryozoans.  The treatment methods for them can be quite costly and very time consuming so we must be absolutely sure that they are the cause of the problems before we take the appropriate measures to eradicate them.

I was not surprised to receive the information and advice from other golf industry professionals.  Turf maintenance is a very tight-knit industry filled with professionals that are always willing to share experiences and offer advice and possible solutions.  Not that I'd ever wish for others to experience turf maintenance issues, but it sure is nice to know we're not alone and that we can learn from the trials and tribulations of others too.  

One of these industry professionals, Kyle Marshall (Director of Golf Courses and Grounds at Capital City Club in Atlanta, Georgia), dealt with bryozoans for the first time back in the summer of 2010.  Just like us, they thought they were dealing with pond algae clogging their heads before testing of samples confirmed it was bryozoans.  Kyle shared with me an article he wrote for his local industry association's newsletter outlining his bryozoan experience and offering some very sound advice and effective solutions.  I urge you to take the time to read Kyle's article so you have a better understanding of exactly what we may be dealing with: When Bryozoans Attack: Perils in Your Ponds

After hearing the nightmarish stories in conversations with other Superintendents, our fingers are crossed in hopes that bryozoans are not detected in our test samples, but we are preparing for having to work through and resolve this problem.

Here are some links to more useful information about bryozoans:

• http://gogtn.org/index.php/articles/water-irrigation/111-bryozoa-reduced-irrigation-sprinkler-flow
• http://www.bryotechnologies.com/golfcourse.html
• http://www2.gcsaa.org/gcm/2008/june/feature5.asp

Clogged Sprinkler Heads

I'm pleased to report that we've resolved the irrigation pump station issues we were recently experiencing that resulted in some severely stressed turf on the course, particularly on our fairways (click here to see previous blog post).  They are recovering nicely, but not as quickly as they should be.  There's a reason for the slower than anticipated recovery: clogged sprinkler heads.  While monitoring the operation of the irrigation system we began seeing pressure issues again.  When further pump station issues were ruled out, we discovered that the screens on the bottom of each sprinkler head are becoming clogged with pond scum from the irrigation pond.  Here is a photo of exactly what we're finding:

pond scum clogging sprinkler heads

difficult to effectively irrigate turf with this issue

Needless to say, sprinkler heads clogged this badly will not operate properly and turf stress and even turf loss are unavoidable until they are back in proper working order.  Here is a photo of the fairway turf condition just short of #3 approach due to clogged screens:

resulting turf stress from clogged sprinkler heads

At this time, the only way to effectively eradicate this problem is to test each sprinkler head and physically remove the "guts" from those experiencing pressure issues to flush and clean these clogged screens.  Needless to say, this is a time consuming process (anywhere from 6-12 minutes per sprinkler head, depending on how badly clogged they are) that has now moved to the top of our priority list.  With over 1200 sprinkler heads on the golf course, this isn't something that gets fixed overnight.

We greatly appreciated your patience and understanding as we work on finding solutions for this problem.

Aeration Recovery & Troubled Greens

The course has now had one week to recover from aeration and I hope you are as pleased with the results as I am.  It just seems to get exponentially better each and every day.  We are back down to normal mowing heights throughout the course, including on the greens, and we started up our growth regulation program on greens again today which will improve greens speed and overall health by reducing shoot growth and promoting lateral growth to increase density.  It's amazing what a little sun, warmth, added fertility and irrigation pumps operating properly (see previous blog post) can do for turf!  The fairways that were experiencing some severe stress are now well on their way to full recovery.  With the current 14-day forecast looking great, we certainly expect the course to continue to improve on a daily basis.

There are a few areas out there that aren't improving as quickly as anticipated, such as the right side of #3 green and the front edge of #11 green.  The turf lost on #3 green is a result of irrigation heads not operating properly.  This green has never previously experienced turf loss like it has this season so we don't feel the need to do anything drastic at this point to remediate the affected area.  We overseeded the affected area during aeration last week and as you can see here we already have new turf establishing:

new seedlings growing in aeration holes

We are going to continue to aerate it with solid (non-coring) tines and overseed it an effort to reestablish the turf lost there.  If we are not pleased with what we are seeing in the coming weeks, we may be forced to go back to the drawing board and come up with another plan of attack.

The turf loss at the front of #11 green is a whole different ballgame.  This is a direct result of a lack of proper drainage.  Water "pools" in this low area due to the higher elevation of the green surround and the turf directly behind it.  It doesn't take much, as little as 2 minutes of irrigation, as seen here, for puddles to form:

puddles after only 2 minutes of irrigation

This puddling is a recipe for disaster and that's exactly what's happened.  #11 green is already our worst draining green due to the actual design of the green surround so lack of proper drainage (slit drainage like on #18 green) greatly compounds the already prevalent drainage issues.

Due to the lack of drainage on this green we will be taking a different approach to correcting the problem.  This coming Maintenance Monday, we will be removing the affected turf and excavating the subgrade to replace it with more appropriate material.  We will also be regrading this area the ensure it no longer puddles after minimal rainfall or irrigation.  This area will then be seeded with ryegrass and reestablished as the collar and first cut of rough.  Doing so will only force us to lose about a 4 feet or so of actual putting surface in that particular spot and will allow it to establish much quicker heading into the fall.  If you play this weekend, you'll notice the white dots indicating where the new front edge of the green will be.

Please understand that it will take time for both of these greens to fully recover, but this work is necessary to improve the overall health and playability of these areas.  Short-term pain for long-term gain.