Deep water wells with high water tables?

Photowhit

I live in central Missouri, and some property has become available in the Missouris flood plane that has an existing deep water well, as the water table is only perhaps 10-20 feet down, I'd take it the pressure involved to lift the water regarless of how deep the well is will be the same as lifting 10-20 feet, as water seeks it's own level?

Anyone delt with a situation like this?

The location is good for doing a small biz of bedding plants, so water would be important.

Cariboocoot

Re: Deep water wells with high water tables?

If the intake for the pump is only 20' down, it's only lifting the water 20'. The amount of water below that level is irrelevant.

But why is there a deep well if the water table is so high? Often it's because the quality of water isn't any good at 20', so you reach down 200' to get good water. Not much sense drilling a 200' hole in the ground if you can get water 20' down, is there? Does water actually stand in the well pipe 20' below the surface? A deep well can 'bypass' higher levels to reach good water down below.

mike95490

Re: Deep water wells with high water tables?

The well should have a sealed caseing, to prevent the deep water at the pump, from mixing with the shallow water, so after a couple of minutes of pumping, you level will very likely be down to 200'

peakbagger

Re: Deep water wells with high water tables?

Deep Wells are used frequently in low yield aquifers to do two things, access active veins in the rock and provide storage when the veins are low yielding. Even though the static water level is at 20 feet, I expect that if you draw water from the well it will drop. If you have conventional pump and tank set up, the pump can draw more water than the well can yield which can temporarilly drop the level in the well which means the pump needs higher discharge pressure. The pump needs to be sized for this drop in well level. The other issue is that the groundwater depth can vary from year to year and the well may have been drilled to account for that.

One way around using a deep well pump is to install a low flow pump (usually a DC solar pump) that is equal or less to the yield of the well and pump continuously into a ground level water tank or ideally an elevated water tank (need to look into freezing issues for either). If you are watering plants, you dont need a lot of pressure, so you may be able to get away wth a gravity system from the tank. If you need the pressure for some of the system, consider installing a variable speed AC pump off the storage tank without an expansion tank. This saves a few bucks on power and makes the pump last a lot longer.

icarus

Re: Deep water wells with high water tables?

To answer the original question, if you have a well that is say 200' deep, and you hand the pump 180' in the well, and the static water level of the well is 20' the EFFECTIVE pumping level is indeed 20'. In doing any calculations I would suggest that you find both the static level of the well, as well as the expected drawdown. My guess is if you are on the flood plain the static level fluctuates a fair bit depending on the season.

Good luck,

Tony

Photowhit

Re: Deep water wells with high water tables?

Thank you all for your help and insight.

Looks like a dead deal as the acerage was over stated...