I have a 70 foot stream with approx 5000+ gph flow (after subtracting head). The width of my stream ranges from about 12-16 inches of water (rocks on the sides add another foot or so). The water is about 2-3 inches deep in the streambed. Then I also have 5 waterfalls ranging from 10 inches to 3 feet tall. Each of them falls into a larger and deeper pool. All that is to say, I donÂt think 3000 or 4000 gph will be too much flow for what you are planning.

I initially tried to follow the 2 inches per 10 feet rule, but I ended up just using a level and made sure that the grade was always going in the right direction (down). I think I may have ended up with something closer to 1.5 inches per 10 feet. Except for the waterfalls, my stream is relatively flat-looking. I do wish I had made a few sections drop more than 1.5 inches because as it is, I cannot create enough of the cascade effect I want (you know, water gurgling over and around smaller rocks, breaking up the flow a little). My waterfalls make plenty of noise, but I also wish I could create more of the lovely babbling brook sound in the stream.

Hope that helps. HereÂs a picture of my stream and then a couple of my waterfalls.
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David you sound like you know what you are doing. Good Luck. I hope other people here can help you with their experiences. Autumn, you stream is beautiful. I'm envyous. David I want to see yours in progress and completed. Sorry I don't have the knowledge. My stream is 45 feet long and after I dug it I tested by lineing it with poly and a garden hose. Made several adjustments and them lined with the rocks. Nothing as fine as Autumn's but it's a start and it works and I'm happy. Keep us posted.

I don't recall where I found them, but there are tables that relate volume of water, width of weir and expected depth of flow in streams.

Bottom line is making a stream that looks good to you in relation to your pond. Lots of ponders ignore the rules of thumb and create eye-catching streams anyway. Intuition and gut feeling about your site are equally important to slope and width.

Good luck - Mike

Autumn,

Thanks for sharing your pond. A great example - with the specs and pictures, it gives me a great feel for slopes and widths that might work for me. Just the kind of thing I was looking for.

In the top photo, how do you have water flowing right up against the rock sides? Does the liner extend right underneath all the large rocks (even the ones in the top left), and you simply try to keep water from flowing behind them?

Also, the water has a strong light reflection, so I can't see the bottom of the stream. Is the liner simply exposed, or how have you covered it?

Thanks,

David

Hi David,

The rocks you see in the first picture along the edges are directly in the lined streambed. So I guess technically the stream is more like 2-3 feet wide. With the rocks along the edges, it just looks like the stream is only 12-16 inches wide, but yes there is some water behind the rocks as well. Even still I'd say the majority of the water volume flows in the path of least resistance.

I used a 10 foot wide liner for the stream to more easily accommodate for twists and turns. If your stream path is going to be relatively straight, 5 feet wide should be more than enough. One word of advice I'll give (from learning the hard way), do not trim your liner too close until the banks of the stream are completely settled (a year later I'm still building up the banks a little in places where it's settled too much). Another mistake I made was I didn't start placing rocks in the middle of the stream until after I trimmed the liner. Adding rocks in the stream raises the water level so I was limited in how many I could put in without causing leaks over the sides. My streambed is only a few inches deep though - if you're planning on a deeper streambed neither of these issues should be a problem.

I do have river rock lining the entire stream so the liner is not visible anywhere. The rocks provides great filtration and it looks more natural.

Here are a couple more pictures, some of construction phase. Hope they help.

Building the stream
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Carving out the waterfalls
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Mostly finished (although it's never really finished ;o)
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Autumn,

Thanks for the additional information.

I assume that most of the rocks in the streambed (at least the smaller ones) are just sitting in place, not mortared or foamed into place, right?

Don't the rocks in the streambed ultimately just get algae-covered, with mulm collecting between and below them? That's the input I get from some - similar warning to "Don't put rocks in the bottom of the pond".

Another warning I've seen, is that rocks simply scattered on the bottom, without either mortar or foam to prevent water from slipping between and below them, will make much of the stream water disappear, and therefore lose the effect.

Curious as to your comments on these reports.

David

David,

None of the rocks are mortared or foamed into place.

The gravel in the stream has not been a problem for me. If anything, I think it provides additional filtration. I do not, for the reasons you cited, have rocks in the bottom of my pond. I've 'been there, done that' so I can say from experience that there is a big difference between rocks in a swiftly moving stream and rocks sitting in stagnant water on the bottom of a pond. When I shut down in the winter, all the water drains from the stream and then I do some cleaning. There is almost nothing by way of debris or build-up under the rocks. Algae could be a problem if your stream is going to be in full sun. Mine's in mostly shade so I haven't had the issues with algae that most have. Mulm is not a problem for me because my water is mechanically filtered before it gets to the stream (pond to mechanical filters (via bottom drains and skimmer) - to pump - to biological filter - to stream). I saw your mention of a polytank filter - is that a biological filter? Do you also plan to have some sort of mechanical filtration? If not, then perhaps the mulm might be a problem as a biological filter will not filter out any solids.

The warning you mention about water disappearing behind and below rocks has some validity, but I think it depends on how much water you're pumping. With 5000+ gallons per hour, there's plenty enough water to fill up a 2-3 foot wide streambed (minus whatever volume the rocks take up) with about 3 inches of water. If you think your final gph will be only about 3000, then you'll probably want to adjust stream width accordingly. As someone above mentioned, there are formulas to figure out the technical aspects of all that - I won't even try as I'm no expert. I can only tell you what I have and the results I get. (I bet Mike_IL would be able to tell you exactly - maybe he'll jump in here...)

Of course, you can always take the advice of most every ponder out there - go bigger than you initially plan because most likely you'll wish you had. If you haven't gotten your pump yet, consider a slightly larger one. Also consider a bottom drain plumbed to a mechanical filter. It goes a long way to keeping a pond clean and clear.

I kind of figured you hadn't foamed/mortared; your high flow rate has taken care of this, and I would think also helps to keep it clean between the rocks. My stream does get a lot of sun, so I may have more of an algae issue.

I already had my liner in before I ever read discussions about bottom drains and settling chambers. If I started from scratch, I'd likely go this route. As it is, I'm considering retro bottom drains, but I understand that churning all this up with the pump before it can settle out is not ideal.

I'm making a multi-stage filter in the poly tank, using vertically mounted Matala media, with successively finer media in each stage. It's 150 gallons, so I figure I should be able to get some significant filtering accomplished, particularly given that the whole system is only about 1300 gallons. I'm assuming with the appropriate densities, this will effect both mechanical and biological filtering, but I suppose I should only talk after next summer's experience.

Given the scale of my project, plus my lower gph pump, I intend to go with a narrower stream than yours, but after having seen yours, you've definitely encouraged me to go much wider as a base, and the use of rock will effectively narrow this down.

It sounds like you have a good plan. I went out and took some measurements this morning just to be sure the dimensions I tossed out were accurate. The stream is at least 3 feet wide (including rocks) in all spots, most of it is more like 3.5 feet (previously I said 2-3 feet). The water depth in the stream ranges from 3 to 4 inches deep rather than 2-3. My gravel is a single layer - just enough to cover the liner. So there's a good 2+ inches of water over the gravel. My pump is rated at 5652 gph @ 13ft. I'm guessing it's closer to 5000 because I know length of pipe and bends, etc. decrease the gph as well.

So I'm guessing that you'll still have pretty nice results with your pump if your stream is just a little narrower.

Would love to see pictures by the way!!

David, your planned pond is similar to mine - my pond is 7 X 10 with a stream that is 15' long with 5 waterfalls of varying height. My weir rocks are approximately 18" wide, the stream is also 18" with a few areas that are wider. If I were to do it over I would make the stream wider and have a bigger pump. I would like to have more room for rocks in the stream and with 18" it is pretty hard to do. My pump is just 2400gph with about 1800gph after the lift. It actaully has a decent flow but after 5 years the weir rocks have settled some so the flow is no longer even across the width - having a bigger pump would help that. I did carve out small pools under each weir rock so the water could pool before flowing over the falls.

Heres a few pictures - the water flow actually looks stronger than depicted here .... also the picture was taken with a fairly long zoom so the stream looks more compressed than it really is ....

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This is one from several years ago .... shows the width of the stream a little better ....

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Hope that helps.

Well, I finally took some pics. Here's the full stream run:

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The poly tank filter at the back will have an adjoining pool from which the main waterfall drop will come. Then the top portion of the stream will end with a shallow pool, which will have a small water drop to the lower stream and on into the pond.

My big question now, is how deep to dig the stream. Here's a closeup of the upper stream:

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The earth to the sides is about level with the mini-ties that keep the dirt off the fence (see top photo). The stream is currently excavated down about 2-1/2 inches from the sides. If I put river rock with 1-1/2" diameter in the streambed, I expect a flow no more that 1" deep, which would put the water level with the dirt at the sides. This is obviously not deep enough, and would look like the stream is practically flowing on top of the ground.

The question is, how deep do I need to go to look reasonably natural? As you can see from the main photo, I can't mound up the surrounding earth much, or it will look way out of place. (I already have concerns about this). When all finished, the left side bank will ramp out farther and more gradually towards the tree, so the "mound" won't jump out so much.

I'm looking for suggestions on where the top of the stream water needs to be, relative to the height of the sides, in order to not look like it's flowing unnaturally on top of the ground. I'm thinking that ideally the top of the water would be 6-8" below the side, but I'm hoping to get away with far less than that; maybe as little as 3"

One last question for Autumn: what is the average diameter of the rocks you used in the middle of your streambed? Is it round river rock, or just your basic gravel?

David

Hi David,

Your streambed is looking great! As for depth - I'd go down another couple inches. Your gravel and any larger rocks you add will raise the water level. I don't think you need 6-8 inches from the surface of the water to the top of the banks though. I would guess that my water level is only about 2 inches lower than the liner's edge, a little less in some areas. It looks like more because the edging rocks are on top of the liner and then I backfilled with good soil right up to the back of the rocks. I do occasionally have problems with leaks over the edge - usually in the fall when debris starts collecting in the rocks. I do keep on top of it and net it during the worst part of leaf season, but I think I'd go a little deeper if I had it to do again.

The small rocks in my stream are river rock - probably 3/4 inch to 1 inch diameter.

autumn - one of the most natural stream pics I have ever seen - except of course the real thing. Congratulations.

So many stream and pond designs don't look natural.

Good selection of round rocks, excellent placement. Not sure the impatients belong there :) but they do look good.

Deeper stream beds come in really handy when evaporation and splashout deminish the water volumn.

I would dig your stream bed deeper to help retain the water--currently doesn't look that deep. If you want 1" of water in the stream bed by the time you get your rocks in the water level is going to go over the edge of your bed. Not sure about that pool--you might find it just collects alot of algae as your slope of your stream doesn't look like it drops that much from the top filter area to your pond. Andrea's construction pics show how far down her stream bed is in relation to the side rocks. Awesome stream Andrea!

What I wouldn't give for a hilly yard. Mine is flat. Beautiful streams. Have been poring through all the posts when I ran across these. Thanks for all the inspiration from all ponders.