Can areas downstream from an artesian well be flooded?

Having come across NinetyWt’s old thread about damn break analysis in my bookmarks, and recently seeing the thought-provoking commercials telling us to get flood insurance*, I have to wonder. I have relatives in suburban Chicago, whose basement was flooded one year. The local stream that did it, when I visited, is in normal times just a tiny brook you can practially step across. I did say “step”, not “leap”. Yet that stream, that runs through a small park across the street from their house, swelled to the point where it flooded my uncle’s basement.

But they are in the heart of the ultrawet Great Lakes and upper Mississippi Valley region, which is probably the wettest part of the country outside the Pacific Northwest. I, on the other hand, live in West Los Angeles, which is one of the driest. Nevertheless, the land parcel directly to the north of my building–and upstream of it–contains an ancient artesian spring sacred to the native Tongva people, who called the place Kiruvungna, “the place where we are in the sun”. Junipero Serra’s party camped there on their way through Alta California, and were given watercress and chia, just as our biology teacher did when he toured us through the grounds.

Usually the water from the spring runs along a short channel to a beautiful pond, set with water lilies, filled with carp and tadpoles, and attended by dragonflies and the occasional water birds of the egret type. Strangely, I can’t remember ever seeing or hearing ducks, as powerful an attraction as you would think this place would be fore them. From the pond, the water runs through another channel and disappears into drain which I imagine leads into the storm drain system. In times of drought or surplus, the flow barely changes at all, and is about 26,000 gallons a day. My question is, could an extroardinarily heavy rain cause the spring to jump its system and spill out over the blocks below it? I only rent, and I think my apartment itself is safe, but we do park our cars in a subterranean garage.

Incidentally, if you read the Wikipedia article, I was one of the students who found the 6000 year old grave they mentioned in the article. It’s fascinating to consider that a family of people gathered around that very spot so long ago to commit their loved one to the earth, and to provide her with things they though would be useful in the afterlife. They had practically no clothes and only the most primitive type of houses, but had music and dance, and creation legends of poetic beauty. They were also one of the few Native American seafaring peoples, plying the coastal waters in large canoes made watertight by being lined with tar.

Artisan springs increase and decrease their water flow according to how charged the system is. My grandpa had one on the farm that came out a pipe that had holes in it. Sometimes it would be down to a couple holes flowing, and at other times all the holes would flow and sometimes water came out the pipe’s top. There was a large variance on that one, but it never stopped. It was along a road and anybody that wanted the water could stop and fill up back then.

Nothing stops a downpour from flooding the whole area regardless of the spring’s water flow.

Well… this depends upon how the spring (more accurately, the aquifer feeding it) is recharged.

If in the case of an aquifer (trapped underground water) which is rapidly recharged by some surface-water source, heavy rainfall could conceivably increase the flow from the spring such that the normal water channel would overflow.

It doesn’t seem very likely however. There aren’t too many aquifers which are recharged so rapidly; it would have to be one with very little storage so that the heavy runoff = heavy outflow, with none of the water taking time to ‘fill up’ the aquifer.

Something else which could occur: the additional watershed around the outflow channel could experience a heavy rain and become overwhelmed.

This reminded me of an interesting ‘flood’ story. There was a mine in coal country which was within a mountain. Over time the empty tunnels had filled with groundwater. This created sort of a ‘perched’ aquifer as the elevation of the water within the mountain was greater than that of the valley below. One day the pent-up water burst through a thin part in the overburden. The resulting flood was very rare in that it was a ‘groundwater’ flood. (Anecdotal story told to me by my 70+ -yr old colleague).

That is a cool story about the Tongva, Spectre.

Harmonious: is it still there?

The spring is still there, but I don’t know if the county allows people to use it. Grandpa’s been dead for a couple decades, so I don’t know who owns it now.

I wanted to link something you might like, but can’t find it. there are two fresh water streams in the world that stop and run at intervals. they have some chamber in the hill that fills and lets loose, because of a vacuum and some kind of goose neck.

Harmonious, I should have asked you: did you notice any fluctuation in its output relative to upstream rainfall? Or was there no correlation to the variance? (Sounds awkward. Sorry about that).

When the wetlands around it were higher the output was higher. The wetlands of course had springs bubbling up in the sand. Not living there The water coming out changed with the spring’s aquifer and not instantly with the surface water. After a wet month it did have higher output. During a month of no rain it was at a lower flow. There is no upstream.

Thanks for the answer.

And glad you liked the local native culture bit. I’ll PM you some more information about that.