Waterfall "sticking" to the side of the rock

[WolfStock]

Hi all,

New pond guy here. I'm putting in a 50-gallon preform pond, with a water run / waterfall into it. I have a really cool rock that I dug out of my front yard actually a couple of years ago. It's got a concave side, which is perfect for the last part of the run and waterfall into the pond. However unfortunately the water doesn't fall "cleanly" into the pond - it kind of sticks to the side of it. I'd like to make the water flow off of the rock cleanly if possible.

Attached is a picture. The top of the rock is angled down at about 10-15 degrees, and the flat front of the rock does angle back some - probably 5 degrees or so. With the pump I have the water has a pretty good flow, but not quite enough to flow over cleanly - some of the water "sticks" to the side of the rock.

I made an attempt to mortar a very small flat rock (about dime-sized) jutting out right where where the water comes off. It helped a bit initially, but still didn't do the trick, and also unfortunately didn't last long - it came off fairly quickly. The rock is fairly smooth and so the mortar didn't stick well.

I also made a small attempt to cave a notch below where the water flows off, but that didn't help at all. I didn't want to get too drastic and make it look ugly, and also the rock seemed to want to chip easily, so I didn't go far with that.

Anyone got any thoughts/tips/advice?

Worst case I could leave it like it is, and make sure that the water that runs down the side of the rock all flows back into the pond (via mortar or some of that spray stuff I've seen), though I'd rather try and make it just flow off the top of the rock cleanly.

Thanks in advance for any help!

 

[koikeepr]

what happens when you increase the flow rate of the water coming out of the pipe?

 

[WolfStock]

I haven't tried that, though I've already bought and used the pump, and it's got about the flow rate I want. So even if increasing the flow rate helps (e.g. by adding some water from the hose to test it), I'm not sure I'd want to do that, since it would require a new pump and probably be more of a flow rate than what I want.

The pic is a bit misleading - it looks like more of a trickle than it really is. My pump is a 330 gph DP330 (1/2 inch tubing). It is intended to be a fairly small setup.

If push comes to shove I may end up doing that, though would like to find a different way if possible.

Unfortunately the rock's lip, while more or less "square" across most of it, is somewhat rounded right at the bottom/center.

One question I'd have is - what might be a really good cement for attaching rocks to each other? If I can find such a thing, I might attempt again to attach a small similar-looking rock at the lip, to form a ledge.

Thanks.

 

[WolfStock]

(P.S. - the pipe isn't going to stay there permanently - it's just there for testing. I'm going to install a rock run up to the back edge of this big rock, and the pipe's going to be behind that as a tunnel, covered by dirt/rocks to look good)

 

[anubias]

It may be flow rate. Have you tried any other rocks?

 

[DrDave]

I use Thoroseal to bond rocks to each other and to seal or repair cracks. It comes in 30# bags and is expensive. I bought a bag 3 years ago and still have some left. In my opinion, it is a great investment.

 

[koikeepr]

What happens if you move the pipe backwards and your water has a chance to get more run down the rock?

I don't see how any cement or product will let you glue another rock to the very end of that one and last very long. Have you tried putting a flat long rock under that one? It would have to be at a slight angle toward the water so the water doesn't go back out.

 

[WolfStock]

I use Thoroseal to bond rocks to each other and to seal or repair cracks. It comes in 30# bags and is expensive. I bought a bag 3 years ago and still have some left. In my opinion, it is a great investment.

Hmmm - I might have to give that a shot, or something like it. The "regular" Thoroseal is colored (white or gray) but I see they have a clear concrete and masonry sealer that may work. It's water repellent so may help the water to flow off the rock better.

Actually that seems like it might be good to use anyhow, to prevent the rock from splitting over time, since we get a lot of freezing here, and it's a rock that I think can flake apart if it gets moisture in the cracks.

Otherwise what I'll probably do is try to attach another rock - either under this one (as suggested above) or perhaps even on the side of this one, like by using a dowel and drilled holes or something.

 

[WolfStock]

What happens if you move the pipe backwards and your water has a chance to get more run down the rock?

I don't see how any cement or product will let you glue another rock to the very end of that one and last very long. Have you tried putting a flat long rock under that one? It would have to be at a slight angle toward the water so the water doesn't go back out.

That doesn't help any, unless perhaps I was to put a high-angled run that flows down into the back of the rock - which might be a possibility actually, I'll see. Your idea of putting a rock under that one is good, and I may end up doing it, though it'll still kind of look odd.

Thanks.

 

[koikeepr]

it won't look odd and will cover the rim of your plastic tub. In fact, you should move more rocks all around to hang over your edge to give it a more natural appearance. If you move them all forward, that one under your main rock won't look odd. You just need to make sure that the ones under the falls tilt toward the pond so you don't lose water.

 

[WolfStock]

it won't look odd and will cover the rim of your plastic tub. In fact, you should move more rocks all around to hang over your edge to give it a more natural appearance. If you move them all forward, that one under your main rock won't look odd. You just need to make sure that the ones under the falls tilt toward the pond so you don't lose water.

Thanks. Yeah I was planning to move all the rocks closer in to make it look better, and you're right it'll be good to tilt the ones on the waterfall side down.

Along those lines - another thing I was thinking about is lining the pond with some kind of a mortared rock lining. It'd be a bit of a pain and perhaps some overkill, but might look a little nicer. Not sure if it's worth the time and effort though, especially if I overlap the edges with good-sized rocks. It has very steep sides, so I'm thinking not.

Meantime - I did go ahead and make another attempt to add a flat rock "lip", mortaring it in a lot more than the previous weak attempt. I'll see how that goes. It seems like the main problem was the curve down right where the water spills over - it's hard to tell in that pic but would be more apparent if the water were turned off.

He's the full pic. I'm going to do a waterfall back just to the right of the doorway, with a water runway towards the pond, then back around the post through the tunnel, which will be embedded in a planter. The whole thing will be in a rock garden context. Should be pretty cool. The tunnel will be back about a foot or so behind where it is now.

View attachment 2479

Another thing I may end integrating is some kind of a wooden water wheel. I couldn't find anything that looks good on the web, so will probably make something. That'll be down the road as time allows tho.

Thanks for the help.

 

[koikeepr]

that photo acually helps. WHy are you using such a big pipe? Is that a 3" pipe? If you used a smaller pipe, you'd probably get more force in your flow!

 

[WolfStock]

that photo acually helps. WHy are you using such a big pipe? Is that a 3" pipe? If you used a smaller pipe, you'd probably get more force in your flow!

Hmm - you'll have to explain the "more force" thing. I'm just using it as a tunnel run, there's no water pressure involved. Does water really run faster through a smaller pipe if it's gravity-fed?

Either way it probably doesn't much matter - the pipe itself isn't actually going to feed the back of the rock. I'm planning to have more aesthetic rocky "water run" of about a foot or two from the end of the pipe/tunnel to the back of the rock - for that matter it may be mostly just a small pool of water flowing onto the rock.

One thing I did try was to test feeding the water very fast onto the rock, by elevating the adding a steep sloped section down to the rock. This made the water run very fast onto the rock, but actually didn't seem to help my "sticking" problem much at all. So I think the velocity of the water doesn't make that much difference.

Anyhow - I'll post the results of may latest rock-lip attempt in a couple of days.

 

[koikeepr]

LOL! I think as much as you're having a love affair with that particular rock, you might have to swap it out for another. It is a cool rock though, and I can see why you admire it.

But yes, if you have water come out of a smaller hole, it tends to put some pressure on it to escape from the hole and can make it shoot out a tad faster. Of course, that all depends on the amount of water to begin with, and your photos are decieving.

 

[anubias]

I think you need a smoother rock or 2 to 3 times the flow rate. The irregular surface of the limestone is causing the water to slow down. Try a polished rock vs. a rough rock and see the difference.