Overflow?

[Meyer Jordan]

If you expect any leaf drop in your stream it is best to make it at least 6" deep.

 

[mgmine]

Make the stream sides deeper otherwise the water will splash out or run out. Don't forget that you will want rocks in the stream bed and that will raise the depth just as if you dug it shallower. Also fill the pond then determine where it levels off. It's easier than trying to guess it before hand. If it is low on one edge build ground up. If it's really high on one side dig a shelf and put rocks to hide the liner. You don't want to see much liner above the water surface.

 

[Marinegrunt]

I built a shallow shelf all around the top edge so rocks can hide the liner where the water line is. That same shelf runs where the stream enters the pond. I was aiming for almost a mini waterfall where it enters. I am having trouble visualizing how it's going to workout out tho. Well, I can visualize it I'm just not exactly sure how to shape the ground the last foot of the stream where it enters. I think once I get the liners in place I'll have a better idea. I guess it's kind of like roofing difficult spots on a roof. You have to visualize the water flow and make sure it doesn't go where it's not suppose to go.

 

[Meyer Jordan]

Decide on what rock(s) will be your weir(s) [spillway(s)] and temporarily set them in place. This will help in visualizing the final water flow. When you are satisfied with the final placement. Pull back the liner and remove enough soil under the location(s) of the spillway rock(s) to anchor them in place. Replace the liner and set the rock(s), gently tamping with a rubber mallet to set and level. Set your framing rock from this point.

 

[Marinegrunt]

Thanks for the tips.

I have a question about the liner for the stream. My 8x20' piece is about 4' too short. I originally planned on using about 15x8 of it for the upper pond and falls. I then planned on cutting the last 5x8' piece in half to finish the rest. I thought my stream was going to be longer but now I wish I would've gotten an 8x25' piece. As long as I don't install the seam in one of the small pools, it shouldn't leak, right? I plan on sealing where it overlaps with polyurethane sealant, but with water flowing downhill, would I ever have to worry about it leaking? It will be basically acting like a shingle, correct?

 

[Meyer Jordan]

Are your overlaps going to be on a slope? What is the grade of the slope? If the overlaps will be at waterfall points, then should be no problem.

 

[mgmine]

You shouldn't have a problem. How wide is your stream going to be? The finished size will be a lot smaller than the rough size. I think you talked about the size in a previous thread. Mine ended up about 3' or less and the liner is 5' wide. Don't skimp on the liner give it plenty of room Consider curves they take more liner.

 

[Marinegrunt]

It's not a steep grade at all and is not going to be on the waterfall. It just won't work out that way. The overlap will be on a straightaway about 3/4 way down the stream. Should I go ahead and get the correct seam tape? I think I remember reading you need a special primer too. Heck, after seeing the cost of the tape and primer it might cheaper buying a new liner! I hate buying that stuff and only using 4' of it. I was thinking about using a mortar base so the rocks stay in place.

My stream should be about 3' wide. Maybe a tad smaller when done. It's not very long. It's maybe 15' from the bottom of the falls to pond.

 

[mgmine]

You don't need a primer just some acetone. I was in the same boat as you and needed to seam two pieces together. I was lucky and was able to get a strip of tape from someone on this site. I had to seam it in place which was a lot harder than doing it on a nice flat surface. I had to use a skate board and piece of wood to support the liner. Is your stream coming off a hill or are you building the ground up to make the falls?

 

[Marinegrunt]

Question....did you ride the skateboard down your falls when you finished using it?

I wouldn't say it runs downhill but just slopes a little. The upper pond is off the back of the garage about 4-5' higher than the bottom pond. I'm basically going to have the main fall which is about a 3 foot drop and then a flat stream. The stream does slope a little. Maybe a foot over 10-12'. It's not going to be a lengthy waterfall.

I did find a 3"x25' roll of seam tape for $20. It's for roofing but I wouldn't think it would hurt anything just using it in a stream.

My phone is trashed from dropping it while working a million times but here are a few pictures. Up top I plan on tying in a retaining wall into the rocks. I had to have the ground higher there due to the garage footing and the frost line.

 

[Marinegrunt]

I could buy an 8x10 liner. If I do that I can have the seam in the middle of the waterfall. The seam tape is $20. Another liner is about $80. Is it worth the $60 more to do that or is there anything wrong with taping a seam especially in a stream?

 

[mgmine]

Too tired to ride the board. It was a lot of heavy work carrying the rocks up to the top! If you have enough overlap you should be fine. To be safe I would do the seam twice. There is quite a drop at the back and depending on the water flow you could have a lot of splash. I would bring the liner up a bit to give it a water proof edge where it drops from the waterfalls. Here is the completed stream. Notice how narrow it looks after the rocks are placed. This is what I got after a 5' liner was put in.

 

[Marinegrunt]

That turned out really nice. Good work!

My daughter wanted a bigger drop with the falls. Do you think that abrupt drop is too much? I did have another step about halfway up but took it out. I have some good moist clay so can reshape thing if I need to. I've taken dirt away and added about 8 times. Since the waterfall is in the corner I tried leaving the sides open so it's viewable from the patio. I figured I could stack rock and use foam to try and keep the splashing down. I'm going to run everything before rocking the stream to see how it goes. I can always flip up the sides and dump more dirt to reform if need be.

 

[Marinegrunt]

I was able to adjust the main liner to where I now have a little more than a 1' overlap without having to put a small piece in and have two seams. It did line up in one of the small pools in the stream but I'm just going to fill that in and dig one further up. Going to pick up a seam kit and should be good to go. I wonder if anyone has ever used the 3M marine sealant. That stuff is amazing and very sticky. I wonder if it would work?

 

[Meyer Jordan]

I would purchase a single piece of 5' wide liner the required length. Seaming should be avoided wherever and whenever possible, but if you are going to seam use the correct materials, those that are made specifically for seaming pond liner. Use of other products is a crap-shoot that may or may not produce satisfactory results.