The Million Gallon Challenge for irrigation conservation

Legwork, math and some capital can help superintendents save water in amounts of one million gallons or more.


Aerial view of Ghost Creek golf course
Figure 1. Irrigation catch cans can be of many shapes and sizes. Photos by John Fech

With ever-increasing pressure on adequate, reasonably priced water supplies, if there ever were a time to take a close look at irrigation efficiency, now is that time. On average, a thorough investigation and implementation of water-saving techniques will bring about a million-gallon reduction in usage over a year’s time.

Sure, this kind of endeavor takes time and money, but considering the price and availability of potable water these days, any reduction in water usage is a great return on investment.

Figure 2. Verifying your central control inventory with what is in the field is a big first step.

It’s broken

irrigation equipment inventory chart

Even if your irrigation system is new, it’s broken. Broken? Really? Wait a minute, what exactly does “broken” mean? If you think about all of the various system components and potential problems that can arise, it’s extremely likely that at least one of them is problematic or at least not working as designed and therefore is broken. Examples include rotors that don’t turn, tree roots that are squeezing in-ground lines, bent risers, water streams spraying turnarounds or cart paths, high/low pressure, grass growing over the heads and so on.

Irrigation for the brown spots

It’s a human tendency: just keep it green. With dozens of other projects on the front burners, it’s easy to push the efficiency of the irrigation system to the back burner, especially when your “hair is on fire” with dealing with disease and Poa issues.

The irrigation for the brown spots routine goes like this: If there aren’t any big brown spots in high-visibility areas, then all is OK, regardless of how long a particular zone needs to run to keep them green. Of course, if Area A is receiving 2 inches, and Area B is receiving 0.90 inches, Area A is getting way too much, but at least it’s staying green during the summer.

The bottom line of the Million Gallon Challenge is to increase overall efficiency to the point where less than a 20% difference exists in irrigation water received by any given turf area on the golf course.

In addition to the waste of water due to inefficiencies, the consequence of Area A receiving twice as much water as it should is the cumulative effect on the root system, one of which is likely to be softened, brown roots due to a lack of soil oxygen, resulting in more brown spots.

Aerial view of Ghost Creek golf course

Irrigation audits

So, how does one know precisely how much water is hitting the turf in various locations on the course? The only real way to know is to measure. Placing catch cans (Figure 1) in the irrigation spray pattern (or hiring a company to do it) will document the amount of water received in each zone. It’s important to use enough cans to measure the output in the various zones as well as adjacent zones, as most systems are designed with overlapping patterns in mind.

In most catch-can operations, aka irrigation audits, the volume collected will vary widely. A typical output pattern would be along the lines of 10 millimeters, 7 millimeters, 17 millimeters, 3 millimeters, 18, 11, 8, etc. Seeing a difference of 8 and 10 is acceptable; in fact, it’s great. However, a difference of 8 and 18 is inefficient. The silver lining is: That’s what we’re looking for — the location for water savings.

golf course management software
Using course management software can help you keep track of equipment placement and how much water each area receives.


OK, here’s where the million-gallon phrase comes in, as well as some nitty-gritty on calculating irrigation distribution efficiency.

An important base formula when calculating water usage and potential water savings is 1 acre-foot of water equals 325,851 gallons, which is the amount of water required to cover 1 acre of land with 1 foot (12 inches) of water.

To gain a perspective on how much land is occupied by turf in the fairways of a golf course, the square footage must be calculated. See the table on Page 43 for sample calculations for an 18-hole course with four par 5s, four par 3s and 10 par 4s. In that case, the total square footage was calculated to be 1,984,500.

Considering that 1 acre of turf equals 43,560 square feet, 1,984,500 square feet/43,560 square feet = 45.56 acres.

The next important formula is for acre-inch, which is similar to an acre-foot, except that it is the amount of water required to cover an acre of land 1-inch deep in water: 1 acre-inch equals 27,154 gallons.

Aerial view of Ghost Creek golf course
Before beginning, double check your field equipment against your existing record.

How much water is required to apply 1 inch of water to these 18 fairways (45.56 acres of land)? Answer: 45.56 acres x 27,154 gallons = 1,237,078 gallons of water.

The natural follow-up question is: How much water would be required to irrigate these 18 fairways during one week? If 1 inch per week is required, then the answer is the same: 1,237,078 gallons. If rainfall is received, then that amount should be subtracted from the required amount; if windy and dry conditions prevail, then additional water is required and should be added to the total.

For example, if 1,237,078 gallons are required in a given week, and the system is running at 50% efficiency as documented by an irrigation audit, the total applied would have to be double of what is desired because the driest areas are receiving half of what the adequately watered areas are receiving. Hence, 2 inches of water or 2,474,156 gallons (1,237,078 gallons/50% or 0.50) would need to be applied for the week. This obviously would result in many areas being grossly overwatered.

 A 30 gpm irrigation heads
Figure 3. A 30 gpm heads run on a block system.

Focus on the big problems

The beauty of a thorough irrigation audit is that it will identify the most serious flaws in the system. Focusing on these during the fixing phase of the Million Gallon Challenge will pay the biggest dividends. For example, if the audit reveals big variances in amounts received on a particular location, whether brown spots exist there or not, digging deep to diagnose the source of the discrepancy is key to the process. These identified flaws are the specific opportunities to take advantage of with the goal of efficiency improvement in mind. Sure, it will cost real dollars to repair pump stations, replace rotors and such, but it will reduce costs and needed water resources in the long run. Portions of an audit can be relatively inexpensive. A central system and sprinkler review can be made with relatively no capital costs and some labor time (Figure 2). Merely compare what sprinklers are listed on the central control to its corresponding sprinkler (and nozzle configuration) in the field. This is a big step forward in tightening up any loose ends at the beginning of your audit exercise.

To carefully document the percentage of water savings after retrofitting, another check of the system output is required. The second audit may seem tedious but is required in order to record the improvement in efficiency.

If the irrigation efficiency is improved by 25%, from 50% to 75%, we can easily calculate the water saved after upgrades and retrofits have been made. Our new irrigation requirement would be 1,649,437 gallons (1,237,078 gallons/75% or 0.75) — a savings of 824,718 gallons from the original 2,474,156 gallons. Even a modest improvement of 10% would save 412,359 gallons (1,237,078 gallons/60% or 0.60) from the original amount applied.

Even with a 10% improvement in efficiency, saving 1 million gallons could be achieved in a reasonable amount of time (less than one month at approximately 400,000 gallons per week).

leaking irrigation head
A thorough irrigation audit should help identify any leaking heads.

Tees, greens and less irrigated turf

Similar calculations should be made for tees and greens and added to the savings for fairways. These parts of the golf course add more irrigated square footage to the calculations and the potential for documentation of water savings. As well, as a result of the focused attention on the high-priority areas, perhaps a reconsideration of the square footage of irrigated turf is in order. It may be possible to stop watering the turf between tee boxes or to change the area adjacent to bunkers from turf heads to landscape drip lines.

Use a pitot tube and pressure gauge to measure flow velocity at a given point in the system.

Pitot tube and pressure gauge

As an example, a small golf course converted its greenside sprinklers from a block system (Figure 3) to a valve-in-head system with an opposing nozzle configuration (Figure 4). It maintained the same total flow of 180 gpm for irrigating greens but reduced runtime from 20 minutes to 14 minutes. This saved the course 1,080 gallons per day. Multiply this by 100 days of irrigation throughout the growing season, and the savings was 1,080,000 gallons. This added 1 hour to its irrigation window and saved $3,000 in electricity for the year.

Calculating money spent on water and its conveyance is pertinent as well as actual gallons of water savings. This number can be compared to the cost of needed upgrades to calculate number of years (or less) required to capture the cost savings, the return on investment.

Convincing your green committee

Now that you’ve established the weaknesses of the system and potential for water savings, it’s likely that approval will be needed to spend the money required for system upgrades or modifications.

After an irrigation audit is conducted, real numbers and evidence are in place to help the appropriate decision-makers agree that an investment is needed to reach the eventual goal of reduced water usage, increased turf health and reduced future water expenditures.

Some stakeholders are visual people, while others are numbers oriented. If the decision-makers you need approval from are business/accounting oriented, the calculations described above will make a big impact. If they’re more “gotta show me” types, as engineers and physicians tend to be, inviting them on to the course to see the results of the audit in person can be motivating. The key to success is knowing a little bit about their personality and preferences and leveraging them to your advantage

Screencap of a twitter post about the Million Gallon Challenge
Figure 5. Social media post — these can go a long way in demonstrating the conservation of natural resources and environmental protection as well as proficient and responsible golf course management.

Aristotle — logos, ethos and pathos

In addition to their professional orientations, consider that most people function preferentially more in one realm than another. The Greek philosopher Aristotle observed these human behaviors and categorized people in terms of three thought preferences: logos (logic and reasoning), ethos (credibility and ethical appeal) and pathos (emotional responses). Making your case using their innate preferences will be more effective if you’re clued into what is natural for each person, or at least using a combination of the three.

Of course, just like with “love languages,” most of us operate in all realms but greatly tend to prefer some over others.

Here’s how that would look:

Decision-makers who are logos oriented: “Through investigation we’ve found that these eight parts of the course are highly inefficient. Retrofitting them with new parts and new technology will produce significant water savings over a four-year period and reduce the amount of money we spend on root diseases each year.”

Decision-makers who are ethos oriented: “Our investigations with irrigation system consultants and university researchers have provided us with the opportunity to take a close look at the efficiency of our current system. We’ve also reached out to experienced superintendents who have conducted the same type of examinations with their courses and learned what does and doesn’t work to reach the objectives.”

Decision-makers who are pathos oriented: “We’ve found that we have a badly inefficient irrigation system. We feel that if we invest a little money in upgrading it, we will be doing our part to conserve a valuable part of the ecosystem and increase the environmental benefits of this golf course — a place for pollinators, songbirds, oxygen production, carbon sequestration and recreation for the golfers” (Figure 5).

Overall, taking a serious look at the irrigation system on a golf course just makes good sense.

Doing so will reap the benefits of reduced amounts of water and associated costs to maintain the golf course, creating fewer soggy root zones that promote fungal diseases and improving the image of the course as a positive community resource.

John C. Fech is a horticulturist and Extension educator with the University of Nebraska-Lincoln. He is a frequent and award-winning contributor to GCM. Brad R. Jakubowski is an instructor in agronomy in Penn State University’s Department of Plant Science.