We have four ponds on our 53 acres here in central NC (zone 7b). I have attached pictures of the two largest (about 1.5 acres and 1 acre respectively for the one with the algae bloom). When I bought this small farm a bit over a year ago everything had been neglected for about a decade. There are a lot of sweet gums here, and it took some months to selectively clear large stretches along the pond edges. Since then, the wild blackberries, sweet gums, and various thorny vines have come back with a vengeance. Maintenance right now involves regular trimming, which takes a lot of time and feels like a lost cause.
I am tremendously inspired by Sepp Holzer's farms and would like to put in more ponds, but my questions are about their maintenance:
How does he keep the bank growth low and accessible? Are there particular plant species like cattails I should be looking at in this zone?
How does he keep his ponds from silting in, particularly with the heavy vegetation surrounding them (must drop tons of debris)?
Locals here seem to be of the consensus that the only option is draining regularly and then bringing in a dozer to fix up the banks and clear the silt. It's expensive and I really hate to do that to the pond-ecosystems. We've looked into dredging but that is way too expensive, particularly if we were to add even more ponds.
I think that with a thriving aquatic ecosystem and sufficient riparian plantings, you should be able to do something even about that algal bloom.
Trees, shrubs, and plants that like the water's edge can act to stop silt from getting to the pond. If you have barrier plantings that act as nutrient and sediment traps, they can trap everything from particulates to leaves and twigs, and other things that would otherwise find themselves filling in your ponds.
What lives in the ponds currently? Do you have catfish, or something else that likes to eat detritus?
I am perhaps getting ahead of myself. I am suggesting that you look more broadly than just pond-edge plantings, as what will make those pond-edge plantings low-maintenance is a fully functional, thriving set of pond systems, perhaps interconnected, and perhaps encouraged to cycle water between themselves, maybe over spillways that would oxygenate it, or pumped up with solar pumps to fountain strategically to the same effect.
I am also suggesting probably some riparian, heavy-feeding tree species like willow, to shade the surface of your ponds and to extract excess nutrients from the surrounding soil and water table that might be causing the algal blooms.
Also, if you can include filter feeders, like freshwater clams, that could help with water clarity and quality issues.
Please let us know how it goes. You have some lovely ponds there. Good luck.
A human being should be able to change a diaper, plan an invasion, butcher a hog, conn a ship, design a building, write a sonnet, balance accounts, build a wall, set a bone, comfort the dying, take orders, give orders, cooperate, act alone, solve equations, analyze a new problem, pitch manure, program a computer, cook a tasty meal, fight efficiently, die gallantly. Specialization is for insects.
-Robert A. Heinlein