Another newbie seeking construction advice

[stavo]

measure along the curve, not a straightline from wfall to neg edge because you need 1/4" of fall for each forward foot down. It'll still flow, sorta, if you do straightline but you'll not get the same pitch.

In general, there's a slight slope from where I took the pictures/front of the pond towards the rear where the berm will be, and a slight slope from right to left when viewing from the front. So as water comes off the waterfall, it actually moves up slope, but as it makes the first right turn towards the bridge, the rest of the route should have a downhill slope.

 

[stavo]

is there a way to calculate this pull? I'm seeing more subsurface as I look at the current plan. The curve and length, to me, seems problematic even if possible. I can understand this neg edge benefit with something like Lisa's pond because the wfall pushes all the surface toward her neg edge. Here, I see a lot of 'help needed' to make the surface make the turn and without any gravity/pitch to help, see how debris could hang up on the south side of the drawing.

edit; looking again, I don't see how any surface debris is ever going to make that curve if starting out on the right side; there seems too much length and no push other than this pull I am asking re calculation. Better be some damn strong pull, imo.

To me, this isn't a good application relative to cost and labor. More digging, parts, complexity and dubious skimming benefit on the rt and center portions. I can see it for the left, but...

I guess I just like the KISS method and this looks unnecessary to me. But, not my pond, so...

Wouldn't the water entering the pond from the waterfall cause a displacement of the water in the pond, causing it to exit at the point of lowest wall, i.e. the negative edge? Or am I oversimplifying it?

 

[brokensword]

In general, there's a slight slope from where I took the pictures/front of the pond towards the rear where the berm will be, and a slight slope from right to left when viewing from the front. So as water comes off the waterfall, it actually moves up slope, but as it makes the first right turn towards the bridge, the rest of the route should have a downhill slope.

water won't flow up slope; you need to have the wfall grade be level at least with the first turn. After that, water will find it's way to the left and downhill.

 

[brokensword]

Wouldn't the water entering the pond from the waterfall cause a displacement of the water in the pond, causing it to exit at the point of lowest wall, i.e. the negative edge? Or am I oversimplifying it?

yes, but not necessarily the surface, which is why you're employing a negative edge. It's a skimming mechanism.

 

[stavo]

water won't flow up slope; you need to have the wfall grade be level at least with the first turn. After that, water will find it's way to the left and downhill.

I'm laughing at my wording on that one. I meant the slope outside of the pond is uphill, but I would make the banks level.

 

[stavo]

yes, but not necessarily the surface, which is why you're employing a negative edge. It's a skimming mechanism.

Okay, now I'm following you.

 

[brokensword]

You do know a skimmer/negative edge isn't necessary, right? Nice feature but imo, not worth the hassle. How much 'skimming' do you think you'd miss if you had to travel a bit? Nothing would harm your pond, it would just mean you have some cleanup upon returning. Putting a net over your pond WHEN THE LEAVES are falling is a lot easier and better as there'll be hardly any work. I'm assuming you're doing this neg edge/skimmer for that purpose? I guarantee, even if you have a negative edge, you'll still get leaves sinking in your pond, esp with the flow pathway as you have it. Half the circle would be skimmed but I can see the leaves bunching and drowning without some good surface force to keep them doggies moving!

All that said, never let it be said I dissuaded a diy'er from having fun. I realize a lot of what we do for the pond returns gratification/satisfaction merely by the systems we set up and maintain. Often in the summer, when everything is supposed to be 'done', I find myself just looking for little ways to enhance/fix/expand the pond. Gives me a lot of pleasure to see what I've wrought, working!

If you haven't seen any vids re negative edge, here's a couple links basically outling what you want to do.

 

[GBBUDD]

You're suggesting the edge where the water goes over is 24" wide, right? Or are you saying the back end of the reservoir should be 24" away from the edge of the pond?

Yes and the bog gets built up as high as you would like so you can create a waterfall of the height you choose. I myself love waterfalls that fall onto an area where it is diverted to one side or split and falls again . WHAT also looks nice is first fall to land ina small pool this makes for a deep sound expecialy if it moves rocks around at the bottom

 

[GBBUDD]

Wouldn't the water entering the pond from the waterfall cause a displacement of the water in the pond, causing it to exit at the point of lowest wall, i.e. the negative edge? Or am I oversimplifying it?

Yes all a negative edge /skimmer or intake bay do is they pull water out making the water in the pond overflow into that area as the pump puts the water in the other side of the pond or bog . Action reaction . The pond water level is just that its level untill water is pushed in one side overflows the other and is pumped back . And its goes round and round. THE ADVANTAGE to a negative edge is a resource for excess water to be stored in the pump vault making this volume as big as you can is always a plus. This allows the water level in the pond to be constant it never changes. And as water evaporates the top off comes from the vault . I have roof drains empty to this area so I don't pay for water. To me there is only a cost disadvantage to the others as it is by far the most expensive but in my eyes the least work and trouble free

 

[GBBUDD]

With his horse shoe you are right the hard corners will trap leaves etc thats why I had pumps/ return jets in those corners. The drawing i did that looks very busy is my set up and yeah its not exactly the kiss theory thats for sure. It is not the most efficient design either as I have added on a couple times now I did not have the narrow section of the pond and the water circulated beautiful I had the skimmer off to the side of the falls that angled AWAY from the skimmer. Why away because I wanted clean water to push circulate the dirty water. Then the two return jets on the opposite side pushed the water in the opposite direction that the waterfall did creating a circulat vortex . And with two drains at the bottom of the pond even at a 6 foot depth I saw small whirl pools worked beyond better then I hoped for. Though everyone thought I was nuts and said the skimmer should be on the opposite side of the pond from the falls. I have a video that shoes a floating go pro that drifted around the pond on its own untill it got pulled to the skimmer in two passes . The current does not work as well but you can't have everything and I've got just about every trick you can do to a pond in that layout . Bottom line the water is clear fish are healthy I can travel and not worry about a skimmer or intake bay clogging. Mother nature helps to restock the water for me so far so good .

 

[GBBUDD]

is there a way to calculate this pull?

Not that i am aware of but go to your tub with a round tupper ware and a cookie sheet place some flating what ever and submerse it and watch what you get. I played with the skimmer when it was running if the water was a foot deep up to the skimmer the draw was little when i filled it in with rock the pull was drasticly increased .

other then that i am not following your train of thought. Your idea of subsurface is when there is depth outside the skimmer if the skimmer only draws from an area that is a 1/2 deep and has a 5000 gallon pump it is going to pull water in FROM THE SURFACE much faster as the 5000 is flowing toward the skimmer no matter how you slice it . now if the water is a foot deep it will pull the waster that is closer to it and from any direction. the entire idea behind SKIMMERS negative edge Even wet dry filters in aquariums is to suck as much water off the surface and get it to a large particle catch and get THE MOST RECENT debris that fell into the pond OUT OF THE POND before it sinks Pretty simple

 

[GBBUDD]

@brokensword
So if you don't recommend a skimmer or a negative edge or a bottom drain whats your solution use a net and or let a submersable pump suck it in chew it up and push it to a bog or filter?

 

[brokensword]

@brokensword
So if you don't recommend a skimmer or a negative edge or a bottom drain whats your solution use a net and or let a submersable pump suck it in chew it up and push it to a bog or filter?

It's not that I don't see the benefit of a negative edge (would be my first choice if I wanted to skim) or a skimmer (my second choice) it's that in this case, I don't see how it's going to be a lot of benefit relative to the extra cost and labor. Other than in the fall, I don't see skimming as necessarily that important. Unless you have your pond under some sort of pollen/seed distribution center. I like KISS, so manually skimming with a pool net every now and then is much better imo, but I've been known to be a cheap bastard, so..

I don't ever see much on my submersibles when I clean them (maybe once a year), especially if you don't put them on the pond bottom. If you have that kind of debris/organics in your water column, you have more issues. Most submersibles should easily be able to pass what normally floats in the water column. As noted above, except during the fall when leaves are dropping. My pond is screened in and I don't pull the top screen off until AFTER the leaves have fallen; for me, I've always got the 'net' on over the pond, it's just 10' in the air and only comes down when winter arrives.

It's mainly all the effort and cost re negative edge I don't think is necessary. I think if you're super into ponding and like to work hard, by all means, put in a negative edge. But you surely don't 'need' one, that's all. I was getting the idea the OP was new at this and imo, for his/her purposes, esp with the shape, doesn't need to make this more complicated to realize the dream.

JMHO

edit; btw, for those reading who have negative edges, I'd be interested in seeing the results of a little experiment. Tie something light to a string then to a wire, in intervals of 4" starting from pond surface height and going downward for 12" or so. Then let the wire dangle near the negative edge at it's deepest part (not at the edge but further our, wherever the pond rises up to create this pulling force) and note which of the tied pieces gets pulled first or at all. This might tell how strong the surface is being pulled relative to the deeper portions going progressively down. Could even anchor this string and like a koi kite in the wind, watch the various strings as you move closer to the neg edge.

Alternatively, you could release some food coloring at various depths near the edge and watch the flow. And of course, gotta film this for the rest of us!

And only the OP could do a real test to see if something floating on the wfall side actually makes it to the neg edge. As noted above, I think you're going to need help pushing toward the negative edge.

 

[GBBUDD]

My pond is screened in

Thats the reason you don't see or feel the need or benefit, your pond doesn't get 1/3rd the organics blown in. it's not just the fall when organics blow in to the pond it is all year long there's milkweed pods Maple helicopters. cat tail fuzz the list is endless. acuza tree berries holly berries Bird droppings the list just goes on and on . And without some sort of skimmer etc the pond surely would be in trouble as not everyone can be at the ponds side to grab the net and scoop out the debris. I could do without a bottom drain But theres no way i would build a pond without a skimmer of some sort

 

[stavo]

I really want to avoid netting the pond, and the arbutus tree I mentioned is supposedly messy year round. So it is important that the filtration is effective.