Although these waves play an invaluable role in shaping culture and are the apex of high-performance surfing, their often fickle nature and remote locales lack the consistency a surf community needs to establish and grow. My experience building surf waves and surfing river waves all over has lead me to this conclusion – consistency builds surf communities. When you have both consistency and quality it’s pure magic, think Eisbach or Boise.

Case in point, look at Boise, Idaho where they can surf year-round. This consistency combined with the quality wave produced by their WaveShaper has fostered an establish surf community including custom board builders like Chris Peterson and a surf shop (Corridor Surf) 500 miles from the coast.

When you have both consistency and quality it’s pure magic, think Eisbach or Boise.

As someone who believes building more surf waves is the future of river surfing, I want successfully built waves in as many places as possible. The reality is that most cities and towns have what I call a “Goldie Locks problem” – this river is too big, this one is too small, and this one is just right. The “just right” rivers are few and far between. Although we have built waves is some very large rivers, they are very expensive and even more challenging than waves in smaller river. For this reason, I have been keenly interested in pushing the limits of building smaller more consistent waves that are also high performance while being more economical to build.

6 years ago, as a surfer in the once small fragmented surf community in Denver where there are very few waves of decent quality and consistency, a golden opportunity arose when local river advocates asked us to transform a degraded stretch of the South Platte into a healthy river with vibrant recreation. Of course, we decided immediately that a surf wave needed to happen. One huge problem – there is very little water (typically 200 cfs or less). We had been planning and designing for several years.

What was maybe two dozen strong before the wave build is now hundreds of surfers and growing.

When I visited Salzburg, Austria in 2014, I saw firsthand the amazing community and level of surfing at the small Alm Canal Wave. It was living proof that this was possible but I was somewhat skeptical it would work as well in a river with varying flows and conditions. We still had some serious challenges to work out. In the end we were able to design a WaveShaper adjustable wave to get the quality and consistency we were aiming for. After two full seasons it is truly incredible how both the size and diversity of the surf community has flourished. What was maybe two dozen strong before the wave build is now hundreds of surfers and growing.

Low flow waves maybe great but you may ask “so what?” The significance, to me, is there are far more places that waves are possible than we all previously thought. More rivers, more waves, more surfing, more fun. Unlocking low flow waves will help cure the Goldie Locks problem. Yes we will continue to see waves built in big and medium sized rivers but I have a feeling we will see even more in small rivers. Watch out for bears Goldie Locks and go surf a river!

By Ben Nielsen, P.E. McLaughlin Whitewater Design Group

The post Consistency Builds Surf Communities appeared first on Riverbreak.

For us flow, hydraulic drop, currents, eddies, obstructions and numerous other factors are the difference between driving through our next carves or not. My passion (and job) is designing waves that not only deal with these dynamic factors but optimises them to create high performance surf waves. How do we do it? One key aspect is adjustability.

Waves Are Extremely Sensitive

A wave is a single point on a spectrum. Above this point is a range of breaking waves and below this is a non-rideable green wave and below that further is a hole (see previous article The Two Types of River Waves on Riverbreak).

For a given set of flow/river conditions there is one specific wave “sweet spot”. This is why some waves only work at very specific flows. You’ve maybe looked at the micro flow effects at your local wave and perhaps noticed the delicate dance the water makes. A small boil or seam from an upstream boulder or a curved current that carries through the wave making it break more or less. Bottom line, waves are extremely sensitive.

Check out how the wave sweet spot is a single point in the video below. This sweet spot is super sensitive.

To further complicate the issue, we want to surf most of the year, at various flows, not just a few weeks a year. And, oh yeah, we surfers are pretty picky about wave shape too. Adjustability allows the wave to change in order to find the sweet spot, stay in it and create the wave shape we need to surf. I’ve designed waves that work with no adjustability but my experience has led me to include adjustability of some kind in all designs.

What Does Wave Adjustability Look Like?

I’ve used several types and have seen countless others. Adjustability typically manipulates one or more of these factors: flow, drop, angle, or bottom contour. Adjustability falls into two categories: real-time and static.

Real-time Adjustibility

Real-time allows adjustment with water flowing whereas static adjustability requires flow to be turned off or diverted around the wave. Examples of real-time systems include The Wave Shaper in Boise, Idaho which adjusts the bottom using pneumatics and hydraulics, or the Alm canal which uses a mechanical screw system to move a plate on the bottom.

In the video below, you see Ryan Richard, the Wave Shaper operator, making the adjustments remotely from the middle of the river on his laptop. Pretty cool right? Even better having Gerry and Tao from Munich in Boise slaying it.

Static Adjustability

Static systems typically attach blocks or other shapes to the river or canal bottom. Although the wave can be adjusted to changing conditions, the flow must first be turned off or diverted around the wave before. Most of the rivers however, are not designed in a way that the flow can be turned off or diverted spontaneously.

The photo below shows Columbus Georgia – this is a “static system” not a “real-time” adjustable feature. We actually never had to do anything to it after it was built worked right away (lucky or good? – who knows a bit of both probably).

Spot: Columbus Wave, Georgia

Pros and Cons

There are pros and cons to each system. Real-time adjustability is typically more expensive to construct initially but reduces costs during tuning and is a good option in rivers or other situations where flow varies (like a river) and flow can’t be turned off. It can also achieve very fine adjustments difficult to do with a static system.

A static system tends to be less expensive up front and is a slightly less complicated design but can require a lot of iterations during tuning to get the wave right. So how do you know which system is best? That’s a tough question. There isn’t a one size fits all system. It needs to be evaluated project by project based on site, budget and performance expectations.

Does Adjustability Guarantee Wave Building Success?

No, but it does improve the chances for success. You can’t compensate for a bad design with adjustability. There have been wave projects built with extensive and costly adjustability that don’t work well. Adjustability will never replace a good, fundamentally sound design that is already near that wave sweet spot.

It is usually cost prohibitive to make waves excessively adjustable or the site doesn’t allow drastic changes to the channel after the wave is constructed, so you have to be close to begin with. Knowing where waves are sensitive and which characteristics are needed is the key to successful adjustability. My approach is to design adjustable features with the precision needed for a non-adjustable wave then build in the adjustability from there at sensitive locations to dial in the wave.

River Waves are a beautiful thing. Let’s keep progressing surf wave design to bring quality river waves to a town near you. Include adjustability in your next wave project, trust me it’s worth it.

To health and high water. See you on the river!

The post The Case for Adjustability in River Wave Design appeared first on Riverbreak.

There are two types of river surf waves — Hydraulic Jumps and Sheet Flows. A Hydraulic Jump Wave forms when fast moving water slows down because of the water downstream, called “tailwater”. There are many examples of Hydraulic Jump Waves:

• Eisbach
• Czech Wave
• Lochsa Pipeline
• Brennan’s Wave
• Boise River Park
• Lunch Counter in Wyoming
• and countless other river waves.

By contrast, a Sheet Flow Wave forms when fast moving water flows over a bottom contour that shapes the wave but is not affected by the tailwater. The best example of this is the Cunovo Wave in Slovakia. Note in the video how much the pool downstream is below the wave – not impacting the wave at all. In general, a hydraulic jump wave is the only type that forms naturally in rivers. I suppose a sheet flow wave could form in a river, but I personally have never seen or ridden one.

Hydraulic Jump Wave or Sheet Flow Wave?

I have been asked which is better a Hydraulic Jump Wave or Sheet Flow Wave? That is a tough question and probably more of a personal preference. For me, I can’t tell the difference when I’m surfing as long as the sheet flow wave is deep enough to ride full profile and stiff fins. Although shallow sheet flow waves like the FlowRider™ are super fun, I prefer the feeling of driving through turns as only fins allow. Hydraulic Jump and Sheet Flow Waves are formed by two fundamental elements — hydraulic drop and flow.

Flow: It’s obvious but without water there are no river waves. Also without enough water it’s not deep enough to surf. My experience is that a minimum flow for a surf wave is about 15 cubic feet per second (cfs) per foot of width of wave (1 cubic meter per second per meter) but this is very dependent on various hydraulic conditions.

Hydraulic Drop: This is energy available to create the wave. More drop equals bigger waves right? Not exactly, there are practical limits. In general, 2 to 4 feet of drop is ample to create good waves.

Neil Egsgard with the Surf Anywhere Project wrote a great article for Riverbreak on the basic elements needed to create river waves. Check it out for more info.

The Four Types of Hydraulic Wave Formations

My expertise is designing Hydraulic Jump Waves. That’s the kind of wave most commonly surfed. Hydraulic jumps are affected by many factors, none more than tailwater, the depth of water in the downstream pool. Depending on tailwater there are typically four unique wave/hole formations:

#1: Pour Over (Lowest Tailwater) — Can be hazardous to river users due to strong upstream currents.

#2: B Jump (Low Tailwater) — A hole formation (breaking wave) that occurs just downstream of the structure.

#3: Max Wave (Perfect Tailwater) — The holy grail for river surfing.

#4: A Jump (High Tailwater) — Hole formation (breaking wave) that occur on the structure.

Video Illustrating the Various Wave Forms

Check out this video during a MWDG physical model that illustrates the various wave forms. Note how the wave form changes with tailwater. Can you find the four wave forms?

As you can see in the video, the Max Wave, what we all want to ride, is very sensitive. The height and steepness needed to surf requires a specific tailwater depth. Herein lies the crux of the wave building problem. To further complicate the matter, there are many variables besides tailwater that affect Max Wave — drop, flow, geometry of wave structure, slope of approach, downstream pool configuration, and others.

How to Design a Max Wave

There are two approaches to effectively design a Max Wave. Trial and error may work in canals and other very controlled environments but still may never yield a Max Wave suitable for surfing due to so many variables or may be cost prohibitive particularly in natural rivers.

Real-Time Adjustability – WaveShaper™ (developed by MWDG) to solve the Max Wave problem. The WaveShaper™ can be adjusted to affect the approach angle, drop, and tailwater relative to the structure – three of the biggest factors. Design is still very important even with real-time adjustability because the range that Max Wave occurs is still easily missed. In addition, the more adjustability a feature has the higher the cost so accurate design is key. The Boise River Park is a good example to illustrate how the WaveShaper™ works and it’s applicability to river surfing.

Static Features – Boulders or concrete structures. This requires the highest level of design and experience to reliably create a Max Wave. MWDG designed a static feature called the Treadmill Wave in Columbus Georgia. In general, the best static feature waves occur with higher flows than required by the WaveShaper™, which is often not available.

Getting your Wave Built

So what does all this mean to ripping your first turns? If you surf a man-made wave already, consider yourself lucky and buy the designers/builders a beer (or two) next time you see them, it’s a great accomplishment. If you want one built in your town, get in touch with an experience designer that has had success building surf waves. If you are keeping it natural, keep hunting around that next bend and hope for highwater. See you on the river.

By: Ben Nielsen, PE, LEED AP

The post The Two Types of River Waves: Which One Are You Surfing On? appeared first on Riverbreak.