As far as I know quarry lakes are created over time as rainwater fills the quarry over years. What keeps an open quarry from getting filled the same way when it rains?
Please tell me if the flair is wrong, I estimated this one to be the closest fitting.
In: 266
It’s not rainwater it’s groundwater. Rainwater in most regions is only a few feet per year, which would quickly evaporate. It’s when the quarry reaches below the local water it seeps in from the sides and underneath. It’s the same reason houses have sump pumps in the basement, although they do also pump rainwater out that saturates through the ground.
You should check out a Cornish pumping engine. The biggest in the US is near Iron Mountain, Michigan. Some of the biggest pieces of equipment in the US and the world are in the Western Upper Peninsula in Michigan. Don’t visit it in the Fall, Winter, or Spring. Summer only!
The flywheel’s normal speed was 10 RPM. Pumping capacity at 1,500 feet was 319 gallons per stroke, or 3,190 gallons per minute. This equaled 191,400 gallons per hour and 4,593,600 gallons per 24 hours.
[https://menomineemuseum.com/cornish-pump-museum#:~:text=The%20Cornish%20Pumping%20Engine%2C%20the,Mechanical%20Engineering%20Landmark%20(1987)](https://menomineemuseum.com/cornish-pump-museum#:~:text=The%20Cornish%20Pumping%20Engine%2C%20the,Mechanical%20Engineering%20Landmark%20(1987)).
Pumps.
Any big digs will eventually need to pump out any water that collects at their bottom.
Here in south Florida our quarries immediately fill with water bc we sit at sea level. Most people think they are just man made lakes. You would never know from seeing them that they are active. South Florida was the 2nd biggest producer of aggregate in the US (late 2000’s)
There is also a natural occurance of this feature, very common near where I live in Ireland.
**Turloughs** are seasonal lakes that fill in the winter when the water table rises as a result of the hogher rainfall and empty in the summer when the water table falls. This is made possible by the very porous limestone rock annd associated underwater streams.
[https://sac.jncc.gov.uk/habitat/H3180/#:~:text=Turloughs%20are%20seasonally%2Dflooded%20lakes,have%20no%20natural%20surface%20outlet](https://sac.jncc.gov.uk/habitat/H3180/#:~:text=Turloughs%20are%20seasonally%2Dflooded%20lakes,have%20no%20natural%20surface%20outlet).
**Turloughs** are seasonally-flooded lakes in karstic limestone areas, that are principally filled by subterranean waters via ephemeral springs or estavelles, and drain back into the groundwater table via swallets or estavelles – they have no natural surface outlet. Most examples flood in autumn and then drain between April and July leaving a dry floor (apart from residual pools). However, some may flood at any time of year after rainfall and drain again in a few days. Their maximum water depth is at least 0.5 m, up to several metres depth. The water is calcium-rich, and the nutrient status ranges from ultra-oligotrophic to eutrophic. Turloughs are typically larger than most seasonal ponds, ranging in size from <1 ha to over 650 ha, and because they receive no surface water inputs, they are less prone to siltation than other standing waters and can therefore be very ancient.
The vegetation of turloughs usually has a distinct zonation determined by water depth and frequency and duration of filling. In Ireland, the vegetation mainly belongs to the alliance Lolio – Potentillion anserinae, but also includes Caricion davallianae mires. Turlough organisms are well-adapted to environmental variation. Their survival strategies include aerial adult forms, production of resting stages, resistance to desiccation, or an amphibious lifestyle. Some turloughs are important feeding-grounds for wintering waterfowl.
Turloughs are vulnerable to drainage or changes to groundwater hydrology, resulting, for example from quarrying or excessive groundwater abstraction, while the groundwater itself is vulnerable to pollution from agriculture, urban areas or roads, and the vegetation is sensitive to overgrazing during dry periods.
Pumps. There was a small abandoned quarry behind my college that had turned into a lake. Fun place to have parties and go skinny dipping. But you could see the layout of it – the rail spur that came in, where a crane/gantry had been to load the rail cars, there were still some pump infrastructure in place that I guess wasn’t valuable enough to remove. Had closed before WWII.
I suspect this wasn’t strictly groundwater filling the quarry as the water level was roughly level with one of the practice fields, but it was very still water with a high temperature gradient. Very warm on the surface, but if you let your feet drop it was very cold.
If the quarry has dug down below the local water table then it’s not rainwater, it’s groundwater filling it up and the only way to keep it from filling is constant pumping to remove the water accumulation from the lower points of the quarry as it seeps in from the ground. An open quarry that extends below the water table is essentially the same as digging a large water well.
Why have flooded quarries the clearest water?
It’s not the rainwater that’s filling them usually. It’ll contribute sure, but imagine a parking lot after it rains, puddles evaporate.
Quarries are often filled back in with water because of groundwater permeation. Where I’m from, lots of quarries are built higher up into hillsides to help remediate this issue, but it will often require installing a large pump anyways to remove water that’s trickling in.
For a great example I recommend reading up on [the Berkeley Pit](https://en.wikipedia.org/wiki/Berkeley_Pit) over in Butte, MT. Open pit copper mine (quarry essentially) that filled back in with groundwater. Several very interesting environmental issues arose as the pit filled with water, it’s got a lot of interesting things about it.
Most working quarries will be pumping out any water that collects within them.
This is done by creating a sump – have you ever noticed that quarries often seem to have a small pond right at the bottom? This is made on purpose so that any water that gets in to the quarry (through rain, groundwater, etc) will collect there where it is safe, rather than flooding the low point of any roads or structures. Once the water collects in this pond, we can just run a pump to shift the water away to a safe spot outside of the quarry where it can drain away safely.
Turn off the pump – such as once a quarry closes – and this water will no longer be pumped out, and the quarry will slowly fill up over time until it find an equilibrium – where enough water evaporates, drains out into the surrounding water table, or overtops and flows away as a stream and the level will stay fairly constant..
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