DIY Pond/Cascade Design Help?

I am hoping for any possible input or thoughts from those here with experience installing small ponds/brook cascades. I read as much as I could but the weather is now changing and Id like to finish this up ASAP! :) This is located directly above my main garden in the hope that some water will be retained in large rains and excess slowly infiltrate into the ground to support nearby plants. Hopefully this image gives a decent idea of what I'm trying to accomplish.

Important facts: Extreme low budget, Canada Zone 5, pond situated 30M above large body of water, about 5 feet elevation over that span.

I am trying to implement a small cascade brook/waterfall emptying into a small water garden that may hopefully support a pair of goldfish and whatever native life moves in year round, including some native transplants to help with oxygen and nutrient cycling.

To help understand the parameters Im working with I labelled the photo:

1: out of picture, a trench swale has been dug terminating at the visible point connecting the main drainage ditch on the property to the top of the falls, hoping that large rain events can help supplement the pond system this way so it does not require filling from the well.

2. plastic barrel I'm hoping to turn into some sort of DIY biofalls, cutting off a side and filling with lavarock and gravel with the pump outlet bubbling up from below and native cattails transplanted on top.

3. salvaged narrow cut of EPDM liner from a previous project placed to hopefully prevent or at least reduce waterloss over the brook/falls section.

4. current deepest spot in excavation, total depth from top ridge is just under 3 feet, it is heavy clay in the bottom and appears to be retaining water well naturally.

5/6. "leftover" components that could be utilized in the system, including a small section of culvert, another patch of leftover EPDM liner, and some bentonite kitty litter out of frame. I would REALLY love to hear thoughts on how to best deploy/combine natural glei/clay/bentonite sealing methods with the leftover EPDM cuts, where should each be placed for best effect? Note, I also have access to seaweeds and horse manure if it makes sense to attempt to glei sections?

So given the materials and design area, i am beginning to question my options and choices. Can anyone offer any suggestions, modifications, tips, or even just predictions on whether this is going to function as hoped? I have yet to purchase the pump which I have been reserving all of my budget for (between 100-200 CAD total). I have a pickup and ability to transport rocks and plants from the surrounding property so I am not spending anything that way. I am considering sinking a milkcrate into the bottom to position the pump on top of, and probably going with a 1000GPH pondboss pump that is in stock at the local Canadian tire.

I know this is a long post but I am really praying for some input here before I "finalize" everything (at least until next year!)



I crossposted this to /r/permaculture, If you are aware of any other resources for this type of project let me know! Maybe the biggest question is how to best deploy the EPDM patches and where I can rely on the heavy clay instead. Thanks!!

First of all, I think you have a lot of great resources to make a nice waterfall, and I'm sure you can do something nice.

I am having trouble visualizing what you are talking about and all of the details and variables involved. I think you would get further with advice and your own personal clarity if you simplified everything into a diagram.  Even on a piece of paper.

I'll throw out some general comments and hope it helps.

It seems to me that you are trying to implement a CHOP (Constant Height One Pump) system.  That makes sense for simplicity, and given the slope you have to deal with.  In this scenario, think of the grow bed as your waterfall. (as it happens, I think your waterfall should *be* a growbed but we'll get to that.)

Constant Height One Pump is not always accurate.  I recommend having two pumps for redundancy, following the same path.  Or slightly different paths if you want a cool "merge" effect.  You don't have to start out that way but its nice to have for peace of mind:  the pump is the one thing likely to fail.

Check out the head height on your pump to see if it can handle the elevation/slope you have, and if so, what the decay in GPH will be.  There is usually a chart.

A milk crate on the bottom to hold the pump does not seem adequate to me.  It seems unstable and also not tall enough.  Given the shape of that depression and the greenery around it, I wouldn't be surprised if you get 2 feet of leaves and debris in there.  The pump will clog. If it does it may overheat and fail, or at the very least not pump water.

I hope you have access to a power main.  High GPH pumps are terrible solar citizens in my experience.

Water seeks its own level.  If you have clay soil up the slope, you shouldn't technically *need* the pond liner for the falls.  It will flow down the lowest channel. However, like you, I would try to line the water paths just to have some control, and prevent erosion.  

Goldfish are good because they can tolerate low temp and are omnivorous.  They are very dirty fish and excrete a lot of ammonia. That's great if you have a lot of filter media surface area and plants to drink up the effluent.  If not, the pond will pollute and there will be a nitrate spike, choking out the available oxygen and iirc correctly upsetting pH balance.

Which leads me to the growbeds.  If you are already pumping fish waste uphill to trickle down, no need for a dedicated filter.  Make little pools on the way down, fill with scoria/lava rock/pea gravel/cocofiber/etc, and they will build up beneficial bacteria.  Bonus is they are a perfect medium for lettuce, spinach, broccoli, tomatoes, squash, etc etc.  Or simply plant with aquatic ornamental plants.  

Also have some of those plants in the water in case the pump fails.  Fish food and insurance.

As for sealing the pond?  Gleying is certainly an option, as is compaction.  You could put bentonite plugs into the sidewalls but I'm not sure how much that would help.  A true gleying with anaerobic organic matter is going to take some time.

Good luck!

Quite an ambitious project if on low budget, having pumps running to sustain some goldfish..
Do you mean Koi? They eat all your vegetation before it will be established. And they are carp who dig in the mud, which you try to seal with bentonite.
Wrong fish.
Did i understand your major body of water is under the pond? These kind of escalating waters evaporate a lot of water.
Maybe it's an idea to double or triple the depth of your pond, only add local oxygenizers, get it established, see if you can get it waterproof and if you're happy with the local frogs/toads/newts that populate the pond. Then the next year add some fish like roach that only start eating vegetation when it's growing strong. And then see if there's need for a noisy expensive water electricity devouring cascade like thing.

I don’t really care about the goldfish (and I did mean goldfish, not koi!), I would be happy to use something like roach if I knew anything about them or could source them here. There is a swale connected from the top so the hope would be to get some recharge from that, with the pump simply providing oxygenation/filtration via the cascade/growbeds.

Ron, thanks for the detailed reply, I’m still digesting it but it seems like you have it figured out. I have seen some people basically using sheet mulching techniques with cardboard/manure/plant material on the higher/more porous edges of the pond banks and I may try that with the liner near the bottom and compacted clay everywher else. Not sure how the edges will work but I guess I’ll figure it out on the go. I definitely will be trying to add pools along the cascade with gravel substrates etc. - hopefully I can find proper vegetation for these areas!

It's Rob, and I believe Hugo is comparing goldfish/carp/koi to roaches in that they will just consume everything with no regard for your plans.  

You certainly could gley this pond, there is no doubt.  It's just going to take time.

Hugo, I think he can sustain a handful of goldfish with one pump as long as there is lots of growbed media and lots of plants.  Also they aren't noisy underwater.  Only when there's a problem. ;)