Compaction of lake bottom

Sorry I can't help...

But it's a very thought provoking question.

The weight of water should compess the lake bed, but silt and sand can be bouyed up by the water? So what actually happens...?

I shall watch the replies with interest.

Del

P=ρH

ρ=1.o for H₂O and =~2 for SiO₂ or clay(silt)

So dumping silt/sand will help compacting the bottom muck loosely settling over the years

For silica it is g=2.65

for the average sandy or silty soil, it is about 2.7. For clayey soils it can be lighter, since clay minerals are less dense, so maybe more like 2.6. high levels of iron minerals or metal minerals will increase the average particle density to as much as 2.8 in regions where hematite, cinnabar, etc. occur. Adding the soil will eventually compact the underlying layers, but as soon as the saturation is removed and the pore pressure and bouyance effects decline, all the underlying soil and the soil placed will settle more. The average density in water is about 2.7-1=1.7, out of water is about 2.7. So by reducing the the saturation you increase the bearing load by nearly 60%. So while you will get some settlement after the fill has and underlying sediment layer dry a little. You never, as a practice, place a fill in saturation over saturated sediments unless you have no other option, at least not with out some means for the pore pressure in the saturated materials to escape, i.e. wick drained, or treatment of the materials.

Another issue is the settling rate, when you are considering anything that must occur over a short period of time. All particles have a settling velocity that is based on the fluid density where they are settling and viscosity. This is where sand helps it settles fast and helps pull some finer particles towards the bottom, and helps stop water currents from re-suspending the finer particles.

You would have to expect that the biomass, which is part of the compressed bottom of the lake, would come into play. It would help to get some more information. Are you filling the lake to the rim? or just covering the bottom with a layer of sand.

Good you ask because there could be some side effects lurking. I'm with del on this one. See what happens. Ky.

Del, please bring popcorn. This is way outside of my realm but is one of the more interesting questions that I've seen. Will fishing be allowed?

Before any answers, more information is needed...

• How much sand are you going to place in the lake?
• The size of the lake?
• What is it's source of water?
• What are you expecting to accomplish by placing the sand in the lake?

These are all important questions because real lakes are rather complicated environmental systems. There are many different chemical processes occurring from the surface to the bottom of the lake. For example, the water at the bottom of the lake is often very poor in oxygen, leading to the support of anaerobic bacteria, which can produce a real witch's brew of chemicals with extreme PH levels. Also, most lakes sooner or later turn, with the water at the bottom trading places with the water at the top in a very rapid process.

This is just a few reasons why more information is needed. Please write back!

Not sure if you'll compact it as if it were a hard coating for a muckie bottom (which was also my nickname from birth to age 1.5 and I recently picked it up again in my late stages of life).

Careful that you don't just move the muck closer to surface, unless that's the goal to have it swept away.

Good Luck,

Muckie Bottom

Hi

you do not need sand or similars, you need the chemical agents that will electrostatically bond the small particles that contain much water together to bigger units to squeeze out the water or most of it.

You will get more information at the wastewater treatment companies, they use the (chemical stuff, slightly alcaline) solution in a small proportion to the sediment enriched wastewater.

Sediment can be organic mud or any organic material and can be also inorganic as clay or fine oxides.

Look for zeta-potential as this will give some information when the suspension will settle and compact.

I recently saw a 1000l tank of the stuff with a dosing unit in the water treatment of a local quarry where a some clay, some oxide and some other very fine minerals are mostly sedimented very simple by adding 0.1% of this solution.

RHABE

Perhaps a treatment including first the method mentioned here followed by covering the muck formed above with sand (which would provide additional weight) to squeeze the muck would be effective.

The short answer is no one knows. Because there are too many unknowns in your question.

Is this a lake or a pond?

Do you intend to fill it up so that it becomes dry land?

How big is it?

Why would you want to do this?

Is this just a stupid question?

Could Del be Right BBQ

Sand isn't a compactor, it is more of a filter. You want a substance to seal the bottom of the lake so it will hold water?

Is there a steady water supply? There has to be some kind of water movement or you'll get a stagnant pond with lots of mosquitoes.

It's that water supply able to keep up with water loss?

Is it really a lake or a pond?

Adding ducks to the new body of water is a good source of silt to seal the bottom. Keep the ducks fed and they will provide lots of bottom building substance. Sometimes more then you ever need.

You could also put water plants in the body of water to develop its ecology. Get the plants started first before adding any other wild life, crayfish will eat the plants rapidly, but if the plants get a good start they can stay ahead of the crayfish and other small water creatures. Then add the fish.

Unless you're involved in a nefarious plan to hide a missile launching site for Dr. Evil, could you please get back to us with some additional information.

Even if that is the plan, could you please offer a bit more information.

cr3