Natural looking pondless stream/waterfall on a slope

[postmandug]

I have been posting in the Introductions thread since joining about a week ago and thought it's time to bring it here where it belongs. My plan is to create a stream/waterfall in a natural drainage gully on the hill behind the house where my shade garden and woodland garden meet. I know the issue with the stormwater will have to be addressed. The stream will be around 50 feet long with a rise of around 16 feet in that distance (Don't hold me to those numbers, I have not measured the altitude variance with any type of equipment yet and in fact my guess from looking at it is it will be closer to 12 feet or so). I had originally stated it would be ~4 feet wide. That is unrealistic. The whole stream may be 4-6 feet wide including the shoulders but the actual waterflow will closer to 2-2.5 feet wide. From some questions from posters on the other thread I also said it would be 4-5 inches deep. That also is unnecessary. I just want a smooth flow so I'm guessing 1-2 inches would be plenty. By reducing my original estimates on size that has also reduced the size of the basin I would need to hold the water when the pump is turned off as I don't plan to run it 24/7. I'm thinking a 300 gallon stock tank is what range I'd like to stay in. My most pressing questions are pump size, pump type (submersible or external and advantages/disadvantages of both), pipe size, use of solid pvc or a flexible type, liner size and if I need a solid roll of liner or can I overlap on a slope that steep with no problems. I do have a GFCI mounted on the back of my barn/storage shed, so electric will be no problem.

Doug

First pic is of the area back in April 2009 with the red arrows showing the approximate top and bottom.
Second one is side view from June 2010
Last one is from May this year looking back down

 

[postmandug]

Had another thought. Since it will not have fish what are my filtering requirements?

Doug

 

[sissy]

mostly yours will be picking up falling leaves and stuff like that .To keep your water clear you could almost treat it like you would a swimming pool bu if you want plants in and around it you will need some type of filter that picks up the bigger stuff like leaves .If you have a lot of shade you will need shade loving plants and if you put some in the water fall and make a filter that holds plants you may be able to get away with only that .Not much filtering really needed .A plant filter may work and add to the natural look .Grasses work great as filters as colleen has said and since adding them to my pond they really do filter the water .

 

[brandonsdad02]

Your basin won't nearly be big enough. Your stream could easily hold twice that amount.. It will take a powerful pump to get the water up that far. Even tho its a gentle incline, it still has to push the water up that far to the top. You will likely need a skimmer box to help keep the surface of the water clean, but with out running it all the time, stuff will sink to the bottom and cause water quality problems.

I was using flex hose, but I changed everything to 1 1/2' hard PVC. Its easy to bend and shape it the way you want.

I would probably use a solid one piece liner for the stream. Since you are using a liner, might as well dig out the basin and make a pond. Add some fishies to it, have a nice, flowing stream with a drop into the pond.

 

[Waterbug]

Had another thought. Since it will not have fish what are my filtering requirements?

Zero. The gravel in the basin is as good a pre filter as you'll find. You'll never have a algae bloom (green water) and even if you did the water in a stream is so shallow you wouldn't be able to tell it was green.

 

[crsublette]

Fun project!! It is going to be awesome when its done. You'll be want'n to relax near it all the time ... before ya know it, ya need to buy more beer!!

50 foot long * 2.5 feet wide * .167 feet deep * 7.48 = 156 gallons. A 300 gallon stock tank will work fine; this gives ya approximately 2 inches more potential depth added to your stream if you want to really throw alot of water down it with a big pump.

How to determine the rating for a pump. Quick example. Aquascape Tsurumi. It is rated for 3630 gph but look at the flow chart. Flow loss occurs with increase head height pressure. If your head height pressure is 12 feet, then this pump's flow is reduced to around 2700 gph. All pumps should have a flow chart in the pump's product description. I have a little dinky water feature and the stream is approximately 30 feet long ((heh, just now went out to step it off)). With my pressurized filter and my plumbing, my head height is close to 15 feet so, using the pump mentioned above, my flow is around 2000gph.

The flow rate definitely determines the depth of the stream. I built my feature so I can divert some flow into the reservoir and, when I do this, I can tell by looking at the stream's rocks that the depth definitely goes down. I am really wanting to double my flow rate to get more depth. That picture is pretty old. I have some taller granite rocks so to allow the water splash around good in the stream and has added some depth to the stream.

Flexible pipe will allow you to possibly reduce head height pressure by not having to use as much plumbing joints.

When choosing pipe size ... To help ya determine friction loss due to pipe size, PVC Pipe Friction Loss and Flow Velocity ... For recommended flow rate due to pipe size at x% PSI, bah, I found a good chart and, son of a, forgot to bookmark it. I would stick to at very least 2 inch pvc.

I have 4 pond-less water features in my front yard. Each has their own basin. After I dug my hole, I lined the hole with some thick heavy duty weed liner as the underlay; then I added 2 layers of pond liner just to make sure they don't get torn. Then, put in some plastic crates. I put my submersible pump in a crate and I cut a door on top of the crate so I could easily get the pump out. Then, I covered the top of the crates with some rock. I did this for each of my water features. I have not had any problems with the pumps getting clogged at all. I suppose the rocks act like a filter, preventing the big stuff from falling into the basin where the pump is. I don't know much about external pumps. I've always used submersibles.

Some stringy looking algae will eventually form in the stream. It will take long time, but it will grow eventually on it. I like it as long as it doesn't get too thick. If it does get too thick, then I sparsely hit the stream with a high pressure washer.

I built big berms on my stream, around 8 inches high; it would take a bunch of damming for water to actually overflow out of it. I got my pond liner extended about two feet extra from the berms on the outside. For my pond-less water feature, I extended the liner a few feet from the basin.

Make sure to make the basin's walls at the right angle so absolutely all of the stream's water returns to the basin, instead of dribbling out of it.

 

[addy1]

My stream liner has a lot of overlapping with out issues. Plenty of drop to keep the water from getting out

 

[postmandug]

Took a few pics last evening of the general area. Also took an elevation measurement. 12 +/- foot lift not counting the friction from water running through the pipe. Speaking of pipe, would flex PVC work OK? 1.5" or 2"??

Doug

 

[crsublette]

I would probably just stick to bigger since 2" has less of a friction loss. I have never worked with flex PVC before so I don't know how it reacts to the climate. For my project, if I used flex PVC, then I could have removed two of my 45 degree joints which would reduce the head pressure a bit.

 

[Waterbug]

Pipe size depends on pump GPH and pipe material. There are tables online you can use to compute how much flow loss you're willing to accept in exchange for increasing pipe diameter and material.

 

[sissy]

Not sure what you mean by temps unless you are talking about freezing and the do sell ground contact pipe insulation .If you are going to bury it run a wire next to it or wrap around it and take pics of it so later you can use a metal detector to find it . I just went through that with a poor lady this morning who got my name from the garden center .It was not the pipe it was 3 plants thats root went up over the top of the liner to get a drink from the pond .I had to be careful as she had no idea where things ran to the pond .Pond builder rip off she got and 10 thousand dollars later and the guy never finished and took off .Well actually she still owes him 2 thousand .Looks like by the paper work and bill, she really got taken .6000 gallon pump for a maybe 4000 gallon pond .Says it is a laguana pump but no name on the pump and laguana labels there's clearly .Oh well live and learn .Don't most pump manufacturers tell you size of water lines and flow rates .You may be better researching the pump you want and see what the pump tells you .

 

[brandonsdad02]

PVC is super easy to bend how you want it. I was using flex hose before but changed to pvc. Just heat the pipe up and form it how you need it. I used my gas grill to heat up large sections of pipe at once to get it to make slow up hill curve while going around a large rock. If you plan it out, you can put in rubber coupling so if you have to shut it down for the winter, just loosen the clamp on the rubber coupling, let the water drain out and take you pump in.

 

[addy1]

The feed to our deck pond is only 2 inches below surface or so, we just take off the rubber coupling whoosh the line is empty and safe from freezing.

 

[crsublette]

Pretty kool idea there brandonsdad02, I never thought of doing that. My only concern is that the weakened walls could lead to a blow out, but there is really no PSI buildup, or at least there shouldn't, to allow something like that to happen. I'm gonna try that.


For discharge, I would always go a little bit bigger. I know there are 6800 gph submersibles that use 2" pipe discharge, but I would increase this to at least around 3".

BTW, I was doing some reading last night, trying to read as much as I can on Koiphen ((a ton of stuff there)). Some submersible pumps use dramatically more electricity to operate when compared to centrifugal, above ground, pumps. So this might be a deciding factor depending on the pumps available to ya. I know the pump above, that I hyperlinked, costs me around $15 a month, after 24/7 usage, on the electric bill.

 

[brandonsdad02]

My pipe is 1 1/2" pvc. That was as big as I could go. I have a threaded nipple on the output of my pump so I screwed on a female adapter to max. the flow that I could. I have a rubber coupling right inside my skimmer box so if I have to pull my pump for cleaning or winter shut down, I just loosen the clamp, slide the pipe out and its free. I wasn't thinking ahead when I ran my cord for the pump and now its buried and runs under part of the bog so this winter I will cut the cord and put on a weather proof twist lok connector in it in the spring. Also if you are worried about the pipe freezing in the winter if you have harsh winters. All I will have to do is pull the pump, blow some air thru the line to make sure is empty and put one of those inflateable plumbing plug in the line and its done. Not only is the line empty for the winter, but its also sealed from mice or whatever might try to make it home for the winter.

The white pvc plumbing that I used is rated for 60psi. Its just regular plumbing pipe that I got at Menards. By heating it up and forming it how you want, you take nothing away from the strength of the pipe. The side wall is still the same thickness. You are just heating it up so its bendable. Same thing they do when they make the pipe at the factory.

I had some flex hose split on me last fall. It was less than 6 months old. I was getting ready to leave in the morning for work and I noticed the waterfall wasn't flowing like it should. I went to check and a frog had gotten sucked into the impeller. Needless to say, after cleaning, I was putting the pump back in the skimmer box and the hose split across the top. Along the length of the hose, across 3 ribs in the hose. Lucky for me, the whole sale house where I got the hose from is in Des Moines, so they replaced the hose at no charge. The took the damaged piece and sent it to the manufacture.