Advice on partially filling in pond

[tabb77]

I currently have a butyl lined pond in my garden which is about 20 X 10ft with shelves going steeply down to 1ft to 2ft and then finally to a 3.5ft deep trench at the bottom. On one side it is almost a sheer drop down to the bottom .

I constructed it several years ago as a koi pond but my plan is now to turn it into a wildlife pond. My intention is to have the pond around 2ft deep with fairly gentle slopes to marginal shelves and a very very shallow slope at one end. Since an awful lot of soil is going to go in and in several places will be a couple of feet high I am wondering how long I am going to need to let the soil settle before putting the liner back over the top?
Also is it best to put most of the soil in and then stamp it down or should I be stamping it down after every bucket/ wheelbarrow full of soil is put in? I am guessing the rain would help it settle down- the only problem is that the soil underneath the liner is clay and very compacted- if it rains the water will simply run down the sides as if the liner was still there and collect in the bottom. If this has a couple of feet of soil added to it I was concerned about it becoming a soft slushy mess- should I temporarily put the liner back over the pond if rain is forecast and then bucket it out again or just let the water run in and hope for the best?

Thanks for any help. :-)

[artdemole]

The bottom where the compacted clay lies should have the prongs of a garden fork down to full depth.Give it a wiggle about.Add some sand to aid drainage in the holes.If you have any stones or rubble the place this on top before adding the top soil.Slightly tamp the soil down every foot.If the liner is going back then the weight of water will take the height down as well.Slope liner away from edge of pond into soil will help.Perhaps more drainage holes away from pond might help.

[Tursiops2]

Hi tabb77

Could you just clarify -you're planning on removing the existing liner, partly backfilling and contouring the bottom of the hole, and then re-lining, yes?

If that's the case, I think, if I were in your shoes, that I'd be looking to use ordinary builder's rubble for the bulk, finishing off with a 6" layer of compacted soil to smooth out any sharp bits. This would be better-draining and less likely to settle after completion, and less work than trying to compact the soil as you go along. I'd be interested to know what others think.

T2

[tabb77]

Thanks for the replies. :-)

Could you just clarify -you're planning on removing the existing liner, partly back filling and contouring the bottom of the hole, and then re-lining, yes?

Thats it. Remove liner, fill in bottom, create new shelves/slope, put back liner

If that's the case, I think, if I were in your shoes, that I'd be looking to use ordinary builder's rubble for the bulk, finishing off with a 6" layer of compacted soil to smooth out any sharp bits

I had thought about using builders rubble but I was put off by having to buy the rubble and have it delivered. I already have a couple of big mounds of soil at the back of the garden from another pond I dug last year so I was hoping to make use of that. I was also a bit concerned that unless the builders rubble was very fine the pile would presumably have gaps and voids which soil from the above layer could get washed into, causing a drop in level.

[Tursiops2]

Originally Posted by tabb77

Thanks for the replies. :-)
I had thought about using builders rubble but I was put off by having to buy the rubble and have it delivered. I already have a couple of big mounds of soil at the back of the garden from another pond I dug last year so I was hoping to make use of that. I was also a bit concerned that unless the builders rubble was very fine the pile would presumably have gaps and voids which soil from the above layer could get washed into, causing a drop in level.

Fair enough, no point buying in if you've already got something you can use. If you're going to use soil, then it would probably be best to compact it as you go, but if your liner overlaps the edge by about 30cm, I don't think erosion/water-logging will be a major issue.
T2