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Nedanstående bilder och text hämtade från Chris Joosses artikel The Model- Soleduck

The Peshastin dam

The Peshastin dam serves a very important purpose- it diverts water to serve local agriculture, one of the area's primary industries.
The primary concern posed by this dam is that due to its shape, it forms a 100-foot-wide pourover hydraulic that poses an extreme hazard to anyone or anything caught in it- this is easily the most dangerous feature on this river, which is already heavily used as a recreational resource.

The dam is heavily signed, (hazard!) The dam is operated by the Wenatchee Reclamation District.

The hazard is this: during snowmelt, (the time when the river is most-used) the hydraulic created by the dam is a drowning machine. It is an accident waiting to happen. What many people don't understand is that this is totally unnecessary- there is no need to accept a hazard as the cost of having a diversion dam in the river.

Currently the hydraulic caused by the dam creates a serious hazard in the middle of one of the more heavily-used recreational rivers in the state. A person or vessel caught in this hydraulic will potentially recirculate for hours unless rescued. (It should be mentioned that life expectancy under such circumstances can predictably be measurable in minutes.) It's not uncommon to watch logs and other flotsam stay there for hours, being driven under, floating back to the surface, then being fed back into the hydraulic by its powerful backflow.

The existing dam is adequately marked as a hazard, and this may be the reason why no fatalities have occurred there. This sort of marking provides some safety, but does not mitigate the lost recreational opportunities potentially available.

The Diversion Dam on the Soleduck river

The opportunity the current situation presents can be seen in the example demonstrated by another diversion dam: The fish hatchery diversion dam on the Soleduck River is known far and wide for the fact that during flood conditions, the wave it creates is nearly ideal for recreational purposes.
The picture seen here demonstrates what is possible with a dam at medium (roughly 3,500cfs) flow. The major difference between this hydraulic and the one created by the Peshastin dam is that objects that enter this hydraulic flush out immediately.

The difference between these two dams is in the shape of the downstream face: whereas the Peshastin dam is a straight dropoff, the Soleduck dam has an uneven, ramping downstream face, which allows downriver traffic (in the case of the Soleduck, drift boats) to safely pass at regular flows.

The proposal is to modify the Peshastin dam to resemble the one on the Soleduck. This modification would not degrade the very important functions the dam already serves- it would greatly enhance the recreational value of this part of the river.

The Wenatchee River between Leavenworth and Cashmere is a summertime recreational resource of considerable value- every year there's a Wenatchee River Festival, featuring competitions that draw competitors and spectators from around the world. This is one of the most heavily-used rivers in the state when it comes to recreation.

The dam at Peshastin has every potential of being the high point of the river, instead of being the low point. It is already a man-made interference, and there's no question that it provides value- what we propose is to add more value to the equation by converting a major hazard into a major recreational asset.

The Diversion Dam on the Soleduck river is a model dam, something we'd like to see anywhere there's a man-made structure in the river. Its chartered purpose is to divert water through the fish hatchery, even at low flows.

Later it was modified from its original design to facilitate the passage of river users- the ramp in the middle allows drift boats to pass, even at low flows as seen in the picture to the left.

Whether intentionally or not, this design resolves the principle safety issues we normally encounter with traditional lowhead dams, at all flows, even those beyond the range of where you'd see Drift boaters on the river. Indeed, at higher flows, this diversion dam forms a water feature that is highly desirable in terms of recreation- the wave works at a wide range of flows and provides safe/easy passage for small craft such as kayaks at any flow.

The result is a structure that not only serves its chartered purpose, (that of water diversion during medium and low-flow conditions to supply the fish hatchery) it also provides positive recreational utility at some flows, without creating safety hazards at any flows. Truly, this is a model of responsible river use.

Se även artikel i forspaddling.com: Konstgjorda forsar och Den perfekta vågen

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A good article by David Weber on how to build your own hole in a river
Hämtat från Playak.com
1. Get the equipment
You'll need your river clothes since you're going to be in the water a lot, as many heavy duty crowbars as you can get, come-alongs or winches, just basically your heavy hand equipment for moving rocks.
2. Decide on a location
You need to find a feature in the river with the potential for a hole. Generally what works best is two large pools connected by a single drop feature. The pool on the up stream side will give you the steady, non-aerated water supply that you need and the down stream side will provide you with the depth necessary to clear the riverbed during moves. In a best case scenario there will be a natural constriction of the river banks between the two pools.
3. Get to work
You're going to be wanting an inverted horseshoe shape, one where the curve bends around the downstream pool (if you can picture what I'm talking about). The first thing you need to do is collect a lot of large, flat boulders, about a meter in diameter at least, but you probably won't be able to move anything much larger. It is very important that they be as large as you can move them so they can resist the pressure that would normally push them down stream. And to be honest, they are still going to be moved around every year, so count on doing maintenance every year in spring.

Now take these rocks and build your inverted horseshoe shape along the riverbed. You want the rim of the ledge to be as smooth as possible. The notches between the rocks can act as sweet spots, areas where you can get your stern or bow through during low water conditions, so don't worry if you can't get the most perfect fit ever.

Now fill in the depression in the riverbed upstream from your new ledge. Again, the bigger the rocks that you use, the more resistance they will have to water pressure.

So what you have now should look like a new ledge in the river, at best a boring class I feature. Now you need to work on the next two parts: channeling the hole and building up the downstream pool.

The first thing to do is to get as many rocks out from immediately under the ledge as possible. Don't undermine the ledge you just built, just get the rocks out and make the area on the river bed which is going to be right below the seem as deep as possible. Building the down stream dam is probably what you should do next, and it's just a matter of putting in a dam several meters behind the hole feature. Done. Be sure to think about recovering from flips when you put in the dam, how much time you'll need versus, how close it has to be to raise the water level at the feature. It should also be smooth so that people don't knock it apart when they go over it. You might also consider making it into a ledge just like the one in the hole so that you can make a second hole later on, should the opportunity present itself.

Channeling the hole is where skill seems to take more of a role. You want the energy of the water to be channeled toward the middle of the hole without restricting the flow over the sides of the hole, and without creating a tongue in the middle that isn't retentive. Naturally, it's done by building up stone channeling walls on the upstream side of the hole which focus the water toward the center. It takes a lot of trial and error to figure this part out. Good luck.

That's about it. The rest involves tweaking the features to get the right hole effects. I'm not sure if the order that I've given you is the best, but it makes sense to me. If you have anymore questions, ask someone else, because as I said I am not an expert on this, just an observer.