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Our country, which is located in thousands of km2 of plains, needs a way to store water. Dams are not an option due to the fact that there are no mountains. We have retired mining quarries that are unused.

  1. What are the implications of using a quarry as a water storage?
  2. How should we solve those implications?

We eventually plan to mine another quarry and build a concrete retainer for the water (to prevent seeping & reduce contamination). And filter and transfer water to the new reservoir.

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    $\begingroup$ I'd say the water would need to be kept circulating to keep nasty stuff from growing in it. Also, where does this water come from if it doesn't come from rivers in the mountains? $\endgroup$ – Lot-Of-Malarkey Oct 17 '17 at 4:20
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    $\begingroup$ I'm not sure if a quarry is waterproof enough to be a reservoir. The implication will be the water shall seep to the ground. I don't know about this, so I'll just leave this here. $\endgroup$ – Vylix Oct 17 '17 at 4:28
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    $\begingroup$ Well at least you are not pumping in reclaimed water. Though I guess my questions would be what was being mined, what is being kept around it afterwards, and how long is that water being stored there? $\endgroup$ – Ferret Civilization Oct 17 '17 at 4:34
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    $\begingroup$ There is one about 90 minutes away from me. They exist. Why not look into the facilities of one you can get to or has an outreach web page? Ask questions of the people doing it. $\endgroup$ – JDługosz Oct 17 '17 at 7:43
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    $\begingroup$ You don't need mountains for dams. If you have rivers running over the plains for any geologically significant amount of time, odds are you will have canyons. Simply use these and build a dam. Less chance of leeching harmful chemicals into the potable water supply and can contain significantly more water. $\endgroup$ – Voldune Oct 17 '17 at 14:03
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Leaching, stagnation

You ask...

What are the implications of using a quarry as a water storage?

The problems are...

At quarries and mines they have broken up and crushed the bedrock to reach mineral deposits. This creates lots of free and mobile substances that will be washed along with the water and pool in the quarry. This is a huge problem for you. You risk poisoning yourself.

The second problem is that this will be stagnant water. This is such a potent problem that when my home town realized that the water consumption in the county was decreasing, the water services had to ask the citizens to use more (cold) water in order to keep the water from turning stagnant in the water systems.

How to mitigate this?

  1. You need to monitor the water quality. Watch for bacteria, parasites, metals and other contaminants
  2. Some chemical treatment to get pollutants out may be needed.
  3. You need to filter the water. This is fairly easy: a big sand bed with a layer of powdered charcoal will get you a long way.
  4. You may need to disinfect the water afterwards. Ultraviolet light (like sunlight) works well.
  5. Keep the water flowing, never let it stand still.
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  • $\begingroup$ How do you keep water flowing in a reservoir $\endgroup$ – mateos Oct 17 '17 at 8:26
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    $\begingroup$ @Albert Pumps. Force that lazy water to move about. :D $\endgroup$ – MichaelK Oct 17 '17 at 8:37
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    $\begingroup$ @Albert this is why most reservoirs are flowing lakes, there is a constant (if small) turnover in water. $\endgroup$ – John Oct 17 '17 at 14:21
  • $\begingroup$ @MichaelK you didn't address leach mitigation. If harmful elements like heavy metals, too much this, that or the other accumulate in the reservoir, then other chemicals must be used to settle out the toxic ones. Filtering won't help. $\endgroup$ – RonJohn Oct 18 '17 at 7:33
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    $\begingroup$ @RonJohn: Modern membrane filters are pretty good; they'll block plain salt (sodium chlorine). This allows their use in desalination plants. Heavy metal ions are much bigger, and are blocked even easier. Note that many heavy metals actually don't dissolve that well, but are predominantly carried as sediments. Those would be caught by the coarse filters before the finer membrane filters. $\endgroup$ – MSalters Oct 18 '17 at 11:32
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The water pH in water that accumulates in some former quarries can be affected by the chemicals used in the mining process and reactions with the exposed rock faces in the quarry.

For example Middlepeak quarry, a former limestone quarry in Derbyshire in England, has a pH level of 11.3; due to its attractive blue colour people would be lured in attempting to swim in it, but they would die. This has lead to attempts to dye the water to make it less appealing to swim in. http://www.bbc.co.uk/news/uk-england-derbyshire-33267461

Other quarries like sand and gravel pits or clay pits are often suitable for use as reservoirs.

Depending on the type of quarry you plan to use it may be necessary to spend as much time if not more treating the water to make it safe to drink after storage as desalination in the first places

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You need to know not only what was mined in the quarry originally but also, and possibly more importantly, what it was mined from, the "country rock" as it's called in geochemistry. If you were for example mining Titanium then it's likely that the country rock is granite and there is likely to be Radium in the rocks, the water will be mildly radioactive and have dissolved radioactive Radon gas. If on the other hand you were mining metamorphic volcanic hard rock for road aggregate like they do in Northland then quarry contamination could include Sulfur, Iron and Asbestos. Lets not talk about opencast Lead or Cinnabar mines, you'd have to be extra stupid to use one of those for drinking water. Other potential rock source contaminates include Copper, Manganese, Lime, Salt, Silica, Antimony, Arsenic, and dissolved Halogens, plus rock dust and other potentially harmful particulate.

That's contamination from existing material, then you have to consider where the water is coming from. Groundwater will likely share the same contaminants as the existing rocks but may also bring in added contaminants from the same list but other areas. Surface runoff from the local area may be contaminated by fertilisers, organic material and microorganisms. Direct rainfall is likely to start off reasonably contaminant free in open country but could include acids, other industrial air pollutants in the form of Halogens, organic toxins or particulate like soot or Zinc dust from powder coating.

Then you have to think about what happens to the water that is in storage, if turn over is low, AKA you are using the ex-quarry for emergency rather than routine supply, then Stagnation is the biggest issue, stagnant water is a breeding ground for any number of micro- and macro-organisms that you don't want; many of these concentrate toxic compounds especially sulfurous contaminants. Evaporation will also concentrate any contaminants left in the water that isn't being used regularly. The other issue is that quarries are usually much deeper than they are wide which leads to generally poor circulation at depth meaning an Anoxic layer generally builds up at depth this leads to a build up of highly toxic Hydrogen Sulfide, which can lead to lethal out-gassing either on site or further down the treatment chain.

So those are the problems, the solutions go a bit like this:

  1. chemical treatment to precipitate dissolved chemical contaminants, this turns dissolved toxic elements into fine powders that settle to the bottom of the water column. To do this you need to know what you're precipitating and how much of it, this requires careful monitoring of water conditions on the surface and at depth. The actual precipitation is usually done after the water has been removed from the reservoir.

  2. bottom sourcing, take the water you remove from the quarry from the lowest point in the system, this improves aeration of the whole helping to prevent anoxia and stagnation.

  3. aeration, pumping air through the water column causes most dissolved gases to be released from solution, it will also oxidise and precipitate metals not previously precipitated. This step should be conducted either in the open air or in a sealed environment where the gas coming out of solution can be contained as it can be highly toxic. Ozone is often used to kill microorganisms at this stage also.

  4. add Flocculents, you may need several different ones to do a staged treatment, flocculation removes suspended particulate from the water, as the dissolved toxins are now particulate precipitates this removes them from the water altogether. Filtration is suggested as a final aid to this process as well as removing larger material.

  5. additives like Chlorine can be used to add to the transport lifetime of the resulting water by reducing bacterial growth and killing existing microorganisms.

As a note you can still dam a river on a relatively flat plain, you built a large earthwork similar in construction to an Earthen Levee that raises the banks of a river and creates both a working head of water and an impoundment space behind the dam for water to pool. This is extremely labour intensive compared to a dam in hard rock at a convenient fall in the mountains but has the advantage of being put where you need it most.

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Quarries make fine reservoirs.

Below: Atlanta's Bellwood Quarry Project

Bellwood quarry project source

Near where I grew up, the best swimming anywhere around was in an abandoned quartzite quarry. I wish I could find an image linked; it was beautiful with clear deep water. All other water around was muddy and green. Google maps shows it is being worked again. The same reasons that led this water to be so clear are the reasons certain quarries are well suited for use as reservoirs.

  1. Structural stone is waterproof. "Quarry" could be used as a catchall term for any sort of mine. Quarries for building stone are the ones to use. The Bellwood quarry depicted above was for granite. Building stones cannot wash away or weather in the rain and snow. Components of a building stone cannot leach away - this would stain the building and compromise stone integrity. Building-quality stone in a quarry will likewise not leach into or contaminate overlying water, and likewise cannot be water permeable.

  2. Quarries are deep. This means a more economic use of land than would be the case for a naturally occurring body of water.

  3. If they fill naturally with water, they fill via springs. Groundwater coming up into quarries can actually be problematic for active quarries. The water quality of a spring will vary depending on the spring, of course, but springs generally are cleaner than surface water sources.

  4. Quarries do not have naturally occurring surface water inputs. Of course if you are working a quarry you do not want a stream pouring into it. Surface water is problematic as drinking water because it carries surface stuff: soil, manure and agricultural runoff. This can contain pathogens. Ag runoff contains fertilizer which then leads to algae overgrowth in the water. Lacking surface inputs, spring fed quarries are nutrient poor and so sustain less life overall than natural water bodies.

If you are going to put water into the quarry (as with the Bellwood project) you can control the purity of what you put in. Atlanta, it turns out, is going to fill it with river water...

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In Poland there is four reservoirs called Pogoria View on four of them on google maps

All were sand open pit mines. Due to water supply coming through limestone water is hard but very pure. Additional sand bed of all of them filter any contamination.

The main problem you would face is how to supply those mines with water. It may be not efficient to pump water directly to them and store for later repumping.

Consider water towers or artesian wells.

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I don't know if there are no rivers at all in this world, but there may definitely be agricultural runoff. Or there could be periods of time where the quarry fills with water because of seasonal rains.

Either of these cases could cause an increase in salinity of the water in your quarry unless you make sure outside water can't get in like that. Not to mention that there could be high mineral content from the abandoned mining project.

Edit: if this is just a store, this excessive saline and minerals could be filtered out, sorry I missed that part of the question.

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As others have said it depends very much on what you have been quarrying. Many materials would make for very bad water storage solution (lead mine), but many others would be fine. The ancient Maya were well known for making use of limestone quarries as water reservoirs and digging specific structures to hold water. This was necessary because in the dry season water often ran low especially in the northern area of Yucatan. But water storage was an issue as far south as Tikal.

It may be necessary to seal the base of the reservoir to prevent or at least reduce leakage. The reservoir bottom and sides might need to be shaped in some places to ensure that water can conveniently be drawn from a vertical edge somewhere rather than a 45 degree incline. Silt should also be provided a place to settle out to prevent it being draw up with the water.

Other key measures that need to be taken: organic materials should be prevented from being washed into the reservoir by clearing the surrounding area of vegetation. Light should be kept out by using narrow and deep quarries or even (as was the case with the Maya bottle shaped underground cavities.

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  • Consider assorted projects to reclaim open pit mines. In Europe those often involve artificial lakes.
  • Where is the water table, compared to the quarry? If it was possible to mine the quarry out, the flooding during the mining operations must have been manageable.
  • If you can work on the floors and walls of the mine, e.g. to seal it, why make it an open lake and not underground cisterns?
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The non-existence of mountains doesn't mean there are no rivers. Some form of river will form anytime precipitation exceeds evaporation.

That said: 1/3 of Alberta is 'land locked' There is no route for a rain drop to run to the sea on the surface. 30 miles from my house is Pigeon Lake, which hasn't flowed over it's outlet weir in 15 years. The lake is about 10 x 20 km, and is having a real problem with blue green algae due to increasing phosphorus levels.

Yet Pigeon lake has several creeks that run into it.

On the Canadian Shield, the last ice age destroyed the existing drainage. It's fairly flat, with mostly rolling hills and rocky ridges. Imagine turning a slab of concrete over very rough from where it moulded into the gravel below. Tip one edge so it has a slope. Run a sprinkler. The cavities fill up, and spill into the next slighly lower cavity. But you can have 'lakes' that empty via multiple channels. You do end up with rivers.

You can think of a quarry as being a very wide well. If you can drink the ground water, you should be able to drink the quarry water.

It's exposed to sunlight, and bird crap, so you will get algae growing in it. But it shouldn't be significantly less drinkable than a lake in similar terrain.

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