I'm looking for general advice, guidance, or suggestions on establishing a garden pond from scratch. Thank you in advance. Details follow:
I'm fortunate for the opportunity to convert 10 acres of late-stage red alder forest in Skagit County of NW WA to gardens and food forest. At its center I want to build a pond excavated from a flat area of shallow hardpan and hydric soils. There are no nearby streams, but there are several forested wetlands on the boundaries of my property. My goals for the pond (in order of importance) are: Aesthetics (adjacent to a future homesite); Recreation (swimming, floating, kids playground, etc); Sink and storage of abundant winter surface water; Drainage of surrounding area to improve growing conditions for future fruit and nut trees; Wildlife habitat; Summer irrigation; Food fish.
What is the minimum size (in acres) and depth that will support all these goals?
Has anyone experience building wetland filtration systems to support the swimming and wildlife goals? I thought a solarpump could be used to circulate water from one end of the pond through a perimeter channel I can build and seed with wetland plants.
Has anyone supplemented a pond with pumped well water to maintain water levels and provide cooling for food fish during the summer?
Can something like this be created such that it becomes a sustainable ecosystem with little maintenance (other than the solar pump)?
Glenn on Guemes
While I haven't done this from scratch, there is a man-made pond fulfilling many of these requirements on my parents property, near Victoria BC. I would guesstimate that this pond is 100' wide and 250' long, with half that area fairly shallow. In last summers drought, irrigating a modest household garden, some landscaping, and 50+ mature fruit trees, it was at perhaps 85-90% depletion before the fall rains restored it; that's the worst it's been in the last 20 years.
It strikes me that several of your criteria can be met by quite a small pond, depending on your exact needs as far as water storage go.
glenn szerlong wrote:Aesthetics (adjacent to a future homesite); Recreation (swimming, floating, kids playground, etc); Wildlife habitat
These are surely quite flexible in size requirements; the pond described above is perfectly adequate... unless you drain it to irrigate!
glenn szerlong wrote:Sink and storage of abundant winter surface water; Drainage of surrounding area to improve growing conditions for future fruit and nut trees; Summer irrigation;
These are a bit less flexible; how much irrigation is probably something you can estimate. Evaporation can likewise be estimated. As to drainage, a farm I spent time on had a much smaller pond, perhaps 50' in diameter and 20' deep in the center, excavated, to lower the water table in a VERY wet valley bottom. I believe the farm owner estimated that it lowered the water table up to a couple feet in the immediate vicinity; she was very pleased with this result.
How much land do you want to lower the water table on, by how much?
glenn szerlong wrote:hydric soils
Food for thought: the pond at my parents was reportedly excavated at least 50 years ago as a source of salable peat, until they hit a seep and it filled with water. The pond at the farm was dug in rich, black, gorgeous valley-bottom soil.
In my parents pond, fish and even water plants fare very poorly, we believe due to the PH; frogs and leaches thrive, but all introduced fish perish, and floating plants do poorly.
On the farm, aquaculture was an intended use, but I was told that this was abandoned as the peaty pond-water would unpleasantly flavor any fish they grew. I don't know how reliable that information is.
So to address your actual questions in order:
glenn szerlong wrote:What is the minimum size (in acres) and depth that will support all these goals?
I would focus on the drainage, as that looks hardest to determine from where I sit. Form an estimate of your water storage requirements, decide how far you are willing to let the level drop in the summer, round up, and once you have an amount in mind for drainage, compare. The other uses seem like they will fall in line.
glenn szerlong wrote:Has anyone experience building wetland filtration systems to support the swimming and wildlife goals? I thought a solar pump could be used to circulate water from one end of the pond through a perimeter channel I can build and seed with wetland plants.
No experience, but I would look at greywater filtration; gravel beds, aeration, lots of plants, etc.
glenn szerlong wrote:Has anyone supplemented a pond with pumped well water to maintain water levels and provide cooling for food fish during the summer?
I would expect a large pond to not need cooling for food fish, unless some exotic species is chosen, and would think that a well designed pond shouldn't need help from the well. It doesn't make much sense to me to pump water to the surface to let it evaporate, rather than using it directly if needed! Conversely, a poorly designed/leaking pond could need a *lot* of help from a well. If the aesthetic part of the pond is that critical, perhaps keeping it small is best so that topping off from a well is practical... Then put another pond away from the house for the irrigation, etc!
glenn szerlong wrote:Can something like this be created such that it becomes a sustainable ecosystem with little maintenance (other than the solar pump)?
The ponds I've dealt with haven't bothered with a circulation/aeration/filtration pump at all, and are quite lovely and entirely self-sustaining thus far. Every now and then we pull a fallen tree out... You might have to compromise where some of your goals clash slightly, is all.
'Theoretically this level of creeping Orwellian dynamics should ramp up our awareness, but what happens instead is that each alert becomes less and less effective because we're incredibly stupid.' - Jerry Holkins