As the snows of winter recede, I am seized with the desire to build a water garden. I plan to have a pool about 4’ X 8’, around 2 ’ in depth. However, I don’t want to have to run an electric line out to the garden (to run a pump and filter). Can I get by without one? I plan to have water lilies, lotuses, and some floating plants (water hyacinth), plus a few fish. So, can I keep the water reasonably clean? Has anybody tried those solar-powered pumps?
As a general question, once the ecology of the pool is stabilized, are water gardens pretty easy to maintain?
Are there any trees overhanging the plot where you plan to site the pond? - the problem of leaves falling or blowing into the water is about the biggest one you could have.
The leaves aren’t the only problem - you’ll need a way to aerate the water as well. The fish and plants are going to need oxygen in the water, and so will the bacteria that decompose the extraneous bits of biological material that the fish and plants will leav in the water. Your relatively deep pool (most natural lakes have a much greater surface area to depth ratio than your design) doesn’t provide a large enough air-water interface to keep the oxygen level up.
I’d recommend some sort of cascade at one end. I don’t know anything about solar pumps, but I don’t see why one wouldn’t work. If you pump the water up to an elevation a foot or so above the water surface and let it flow over a few artfully arranged rocks, that should provide enough oxygen to the water to keep it from becoming a foul stagnant morass.
The answer to your question really depends on what you’d like the garden to look like.
By using the right species, you can have a wonderful water garden that requires no care aside from occasionally thinning the plants and cleaning out sediments.
OTOH, If you’d like clear water, which most people do, you’re pretty much stuck with a filter (and more maintenance).
An aeration system is not absolutely necessary, as described above, but for most ponds it is a good idea because people tend to load the pond up with too many plants and/or fish.
Speaking of fish, ammonia is the most serious problem to look out for. Regularly clearing the sediments or artificial oxidation are really the only ways to prevent buildup of ammonia from breakdown of plant material and fish waste.
If you’re really itching to get started this year, install the pond and a few plants (in pots-much easier this way). Watch amphibians, dragonflies, beetles etc. colonize it and decide about adding fish later. You may find you enjoy a fishless pond just as much.
Out out curiosity, why don’t you want to run an extention cord out there?
When I first had my pond, pretty much the same dimensions as yours, it worked fine for the first two months or so. After that it started getting murky and swamp-like, even though I only had a few fish… that’s just the way stagnant aquatic ecosystems work - check out any slough and you’ll see this. The clear-water “pretty” ones either have lots of aeration (from wind/waves) and/or an incoming source of water; usually with an exit too.
If filters/pumps are a definate no-no, do your best to shade the pool either by locating it out of direct sunlight or by using plants that cover a lot of the surface (lilies, floating plants, etc…). Once you get lots of algae growth (and inevitably death) along with warm water and high microbial activity, your water will start eutrophying pretty quickly, and tends to turn anaerobic if it’s not mixed well.
You could always try setting up a little wind mill to mix the water, though I’ve never actually seen that done personally. Even a small air pump will help out, though those do require power. Lastly you could choose fish that are tolerant of warm polluted water; there are quite a few. Back in my less knowledgeable days when I had that first pond I mentioned above, I had a couple goldfish doing ok in it. I threw a small trout in and it immediatly went into a violent alarm resonse due to the low oxygen content of the water, and was dead within a couple days. On the other hand, my weather loaches were pretty near indestructible… seeing as they can take a gulp of air from the surface and live off that.
And yes, once established an aquatic ecosystem is pretty stable. The bigger and more resistant to physical/chemical changes the better. What screws it up are large changes such as cutting off the filter for a wekk or two (or starting one, though that’s usually a good change), loading up too heavily on fish or fish food, huge water changes, introducing diseases, and so on.
You can go to an electrical supply shop and ask for BX cable, which is direct-burial electrical wire, if you want to run a pump. You’ll just need to dig a trench from 6 inches to a foot deep to run it through. A bit of work, yes, but a pump makes things like this so much easier.