Backyard Aquaponics
A place to discuss aquaponics

Ok, here's the situation. I have no real experience with hydroponics or aquaponics. In about four weeks, I am going to finish building two outdoor ponds (about 1.25 and .75 acres each). I live in Missouri. These ponds are fed by a fairly large spring which puts out anywhere from 300 - 2500 gallons a minutes of water at about 57F degrees year round. The spring runs into the large pond, then spills into the second pond.

The more I've read lately, the more I am considering building an "aquaponics" system between the two ponds. I'd like to do whatever I can during initial construction to facilitate this effort. This won't be a recirculating system and will not have any electricity initially (I could plausibly add electricity later). Assuming a fairly high stocking rate in the first pond, I will have a constant flow of gravity fed, nutrient rich water leaving the first pond. The space between the two ponds is relatively flat and spans about 40 to 75 feet, depending on exactly where I place the spillway. Supplemental aeration would be available if needed.

My goals are to have a very low maintenance system that can provide some reasonable supplemental vegetable growth for someone with no experience. I would spend additional funds on this project if doing so added substantial benefit, but am clearly in the "just try it" mode.

My current thoughts: set up the spillway to overflow into a large clay-lined trough (made similar to the construction of the main pond) about 10' wide by 40' long by 2.5' deep. I would fill this trough with gravel, allowing the water to gravity feed into it--in what I understand would be termed a continuous flow system. At the end, it would have another spillway to send the water into the next pond (hopefully in better condition for the fish in that pond) that would maintain a relatively constant level of "wet" gravel (with water level about 2 inches below the surface?). Theoretically, I could have several of these types of setups between the ponds or below the second pond. I'm thinking this would give me a largish gravel area that would only grow what I put there (maybe I could put down some landscape fabric or other obstacle during any off-season to minimize weed growth?).

Now--My questions:

1. Does this sound plausible?
2. Major problems anyone anticipates?
3. What size gravel would you suggest?
4. How rapidly will the gravel fill in to prevent the free flow of water through it (assuming I can keep infiltration of outside debris to a minimum)?
5. Considering the water temperatures (about 50-65F degrees year round) and less intense fish population than many use, what kinds of vegetables might I reasonably expect to thrive?
6. What else should I be thinking about that I'm overlooking in my ignorance?

Sounds like you have a nice situation there. Welcome and good luck with it.

Just so you know, most of us are set up as Flood and drain and that is the method that most of us have numbers for. That aside, adding gravel beds with veggies to the spillways will greatly improve water quality for your second pond as well as mitigating negative effects on the water leaving your property.

I'm not sure how long it would take for things to get "clogged" that will largely depend on 1-debris 2-stocking/feed rate in relation to amount of area that the water has to spill into since that first entrance of the water into the gravel is where the clogging will be the worst.

What plants you can grow will vary. I'm sure lettuce will probably like the set up though you will have to watch for "wet feet" on many other types of garden plants. There are many water or marginal plants that might be of use to you there though.

However, since the system will be flow through, you may have trouble building up much nutrients for many types of plants so you will have to experiment and see what works.

Good Luck with it and keep us posted as to your progress

I've actually considered doing this as a flood-and-drain. I think all I would have to do is channelize the water in a smaller channel, use a small pvc pipe to "fill" the growbed and then have a larger PVC autosiphon to "drain" the water back into the channel. Any thoughts on whether the benefits of a flood-and-drain would be worth the added construction?

Rice patty in the field? If the situation allows for it I would slope the bottom to a single point and provide a bottom drain. Then in the future if you ever need to you will have the ability to drain out the poop and rotting leaves ect.

I think a bottom drain would be fairly straightforward. I don't see how it can hurt to have one.

Exactly. If you never need it then nothing lost, but if you did need it and did not have one..

TheMoMule welcome
Yeh no ammo spike and no nutes...
The BYAP concept of closed loop farming is that the system deals with the waste (byproduct)
by turning it in to nitrate a useful product, through the 'nirtification process'.
In order for this to happen, the 'cycling' that ocurs as a result of a spike in ammonia
followed by >nitrite>nitrate,ammonia>nitrite>nitrate eaten up by some good bactereria
would not happen until quite some time passed... and as you have seen in may rivers and streams
algal blooming or redtide or bluegreen sometimes happens.
This is overload, once this happens the water will take a long time to come back,
possibly as long as it took to get there
Without intervention(sp?) such as biofiltration(nitrification) where the water can be effectively filtered by the plants,
airated, and passed through filtering stone(hydroton [expanded clay]) gravel beds or other media (BYAP)
ammonia will continue to accumulate as a latent problem.
I have taken a while to compose this so prolly has already been said

I think I understand the concept. The benefits of the bio-filter normally are fed back into the same fish-laden water to be recycled. In my system, the bio-filter fulfills the same function, but discharges into a different fish-laden water (the second pond). I realize this isn't a closed system as found in the traditional AP system. However, it seems I should be able to improve water quality in Pond #2, generate some vegetative growth and do so without any added electricity, water use or fertilizer inputs. I'm trying to get some of the benefits of traditional AP while working with the realities of my site.