It may work, with a few modifications. Realize I am not an expert in ponds, but I do know some of the basics.

First, water draining through the soil and into the pond spells trouble with a capital "A" for algae. You would be fertilizing the water and causing an algae outbreak. The best way to keep you water clean (IMO) is to limit nutrients that get into it, and grow water plants that remove them. and you will NOT be able to fertilize the plants, as some of that will inevitably get washed into the pond. Plan on never adding additional water to the soil, if at all possible.

The other immediate problem is that you will need to put some kind of barrier between the soil and the gravel. Otherwise the soil will filter through the gravel in time. The island surface will sink, and you will have fertile soil contaminating you pond. Then you've got the "A" problem again.

If you use concrete, will the leaching lime into the water be detrimental? Anything living - plants and especially fish - could die. I am not an expert here. A good qestion for the pond people, but then you probably know.

I wouldn't try more than one unit until you find it causes no problems.

ill leach the lime out of the concrete prior to filling the pond. i already have a concreate wall in my current pond, and it has caused no problems. the idea is that the plants in the concreat walls will use the nutirants in the water as the food. i have in the two years i have had my pond had no alge infacti have chrystal clear water to 32 inches when its up and running... from what i rememebr of soil chemestry the nutirents wont leach out of the soil too fast if i use the right kinda soil mix, and even if they do they will quicklybe taken upo by the numerous water plants that i have, especially the cattail wich are great filter5 plants for nitrates. im basical trying to build an out dore terreaium, i sort microcosm. but in the open air.i am wondering what will happen when some of the plants and shrubs roots get down to the " waer table" in theory they should develope hydroponic roots if they even decide to grow down that far at all. this structure will be quit large nd will also hold some trees kept in a psudo bonsai manor.

Sounds to me like you've got it all under control. I'd wish you good luck, but I don't think you will need it.
Rick

im hopeing so....... im doing atlot of rersearch and want to make sure i have this well thought out and designed before i start construction.................what i need from this forum how ever is to know more about rock gardens and groing things in concreat troughs

Thant sort of concrete boxes ?

The making of

This one in french language only, but you can have a translation with google translator...

Here is a link that might be useful: Concrete box

im looking at useing hypertufa..............as i have been desinging the pond i have came to the conclusion ( and after talking to my supervisr) thatit migh be possible to incoperate an alpine garden int o a filter. by this i mean that i would build a stream that has alot of sand and rocks in it and build up the shores of the stram so that the surface stays dry. i could then plant alpin plants along the stream banks and wate rthe plants with the pond water as needed.. same princible as above. but this would serv to strain the water, and the rocks and waterfalls woudl aerate the water, so with a 30 ft trek i woulkd get a rathe substancial filter, and provide a place to grow alpine plants, and there for have an alpine stream, well for the most part. there is a crab apple that would be in the middle of the bed, i dont know if that would kill the effect or not. right now i have forsythia and some peones, and junpiers there, the forsythis is planted as a hedge and i dont really like them. they are alot of work, but mayebe if there is an alpine vine i can grow o the fence that would serve the same pupouse

What's you're looking for are a wet moraine's alpine plants.

Moraine is a sort of scree, with running water a few inches under the surface (Generally this water flow only in sping time and comes from the melting of ice and snow of the mountain)

Wow. If you make a moraine like you describe, you could grow alpines that few others have success with. Pretty exciting, I'd say.

ohh i would like ones that can live right close to the water but i can do differnt onse just by variing the height of the gravle over the water table. thing is this would be a constantly flowing stream. ok class have a seat. in aquatics there is a type of filtration called phyto_ filtration. this is where plants living in the water or in contact with the water remove nutirents from t the water thus makeing the water cleaner, and helping to reduce the chance of alge. the more plants in contact with the water, the less nutirents. another type of filtration is bio filtration. in wich water is passed through a medium such as sand or gravle and bacteria living on the surface of the rock or sand grains, break down the amonias into nitrites and then in to nitrates. essentialy what im planing here is a 40' filter, with water falls to areate the water. i would pump some of the water on to the beds when they need to be watered, thus supplying random in frequent phyto filtration. plants that could live wit there roots in water year round would be great but im not sure that is an option with the alpines. ill have enough plants in the pond and the surounding beds wich willbe with in the pondliner that i should be ok on phyto_ filtration. the alpine garden in my oppinion would be a great way to disguise one hell of a send and gravle filter. basicaly building the flower bed on my filtration media.i do have some designs that i would like to run past you as far a s how the stream and falls would cut through the bed. but this will be a later project probaly the summer 2007 depending on my finances, but the more i poan this out the better it wil work and look. who knows maybe someof yu guys will find some usefull info from this endevor and maybe build some thing simiular.

later days Parker

This is all a very interesting idea, Parker, and would look fantastic if landscaped correctly! The one thing that concerns me is having all that sand/gravel/planting media in the water...especially the stream.

1...you will have to design it carefully to avoid the water from both the stream as well as rain, from washing all your hard work into your pond.

2...the stream bed will act as a filter, both bio and mechanical. But...all that media will quickly clog with muck from the pond and debris that falls/blows in. Once it is clogged, there goes your bio filtration and with water contantly running over and through it, it will be dumping all those nutrients back into the pond. I only keep a very thin layer of river rock in my streams and even with that, it collects an amazing amount of junk that gets cleaned out yearly. Cleaning a stream as you describe would be a huge task and you wouldn't want to be tearing up the thing yearly.

Just my initial reaction...maybe I am missunderstanding your design...

actually there will be a pool at the head of the stream, kinda like a bog garden with a fountain in the middle of itill be pumping water in to the pool at between 5000 and 10000 gph, the pool will work as a sorta settleing tank for the gunk. and that should help alot with the stuff clogging up the stream. the stream wont empty back into the pond as my terain doesnt allow me to do this with out sacraficeing my large falls so the stream will end in a small pool and that water wil be pumped up in to the large falls of the pond. im also trying to fighure out a way to use the header pool as a mechanicl filter, by laying the gunk on top of the media and letting that catch the stuff, and in tern buliding up aloam for growing bog plants in