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Hi Again, Jul 18, 2012
The effect would be due not to the higher water table (actually lower at
'high' tide) but to the associated increase in porosity.
A lowering of the water table by 0.2 to 0.4 feet implies an increase in
porosity somewhere within the aquifer and logically (other things being
equal) not far below the watertable, i.e. much less resistance to flow.
Hydraulic conductivity is very sensitive to porosity and an increase of a
few percent can translate to a 10 fold or 100 fold increase in conductivity.
Yt, DW
----- Original Message -----
From: "Stephen R. Shaw" <srshaw@Dal.Ca>
To: <naturens@chebucto.ns.ca>
Sent: Wednesday, July 18, 2012 12:56 AM
Subject: Re: Earth tides; Fw: Pump drawdowns: [NatureNS] Freshwater
Shortages and Bay of Fundy Tides
> Hi Dave,
> A really informative find from USA. This report including the phenomenon
> of earth tides (distortion of the earth according to the relative
> positions of the sun-moon-earth) sounds like the probable explanation.
> An extra height of 0.4 foot max (in Missouri) is not that much, but a
> careful observer like farmer Gerrits might well have spotted it and got
> extra water for a bit longer from the high points.
> Patricia: you might want to relay this to the farmer if you meet again,
> and tell him to skip to near the end of the PDF file, looking
> particularly at the earth-tidal oscillations in height of well water in
> Figures 10-12.
> Steve (Halifax)
>
> Quoting David & Alison Webster <dwebster@glinx.com>:
>> Hi Steve & All,
>> Sounds like an earth tides effect---
>> http://www.dnr.mo.gov/env/wrc/docs/whywaterlevelschange.pdf
>> DW
>
>>>>>> ----- Original Message ----- From: "P.L. Chalmers"
>>>>>> <plchalmers@ns.sympatico.ca>
>>>>>> To: "NatureNS" <naturens@chebucto.ns.ca>
>>>>>> Sent: Friday, July 13, 2012 2:28 PM
>>>>>> Subject: [NatureNS] Freshwater Shortages and Bay of Fundy Tides
>>>>>>
>>>>>>
>>>>>>> For most of my life, my family home in Bedford was dependent on a
>>>>>>> drilled artesian well, as there was no municipal water supply in
>>>>>>> our neighbourhood. This is no longer the case, but I am still
>>>>>>> acutely aware of how valuable water is, and curious about
>>>>>>> hydrology. I was in the Annapolis Valley last week and saw how
>>>>>>> very dry the fields and orchards were there. So last Saturday, at
>>>>>>> the Halifax Seaport Farmers' Market, I was asking some of the
>>>>>>> farmers how they were getting on in the present drought.
>>>>>>>
>>>>>>> I had an interesting chat with Greg Gerrits of Elmridge Farm.
>>>>>>> Since there was so little snow last winter, and since it was such a
>>>>>>> dry spring, his normal water supply is down at least 40% from
>>>>>>> normal levels. He doesn't have enough water to irrigate more than
>>>>>>> a few acres at a time. However, he went on to explain the
>>>>>>> influence of the Bay of Fundy tides on his water supply. He said
>>>>>>> that the weight of incoming water in the Bay was sufficient to
>>>>>>> exert pressure on water deep below the ground, even where he farms
>>>>>>> (near Sheffield Mills, I think). The flow of fresh water into his
>>>>>>> well improves significantly when the Bay is full of salt water. So
>>>>>>> he has learned to schedule his irrigation so that it begins three
>>>>>>> hours before high tide, and stops three hours after high tide.
>>>>>>>
>>>>>>> There are so many kinds of knowledge that a successful farmer needs
>>>>>>> to have, but it hadn't occurred to me that a knowledge of the tides
>>>>>>> was one of them. I may not be representing this very well, but I
>>>>>>> found it intriguing; perhaps someone could say more?
>>>>>>>
>>>>>>> Patricia L. Chalmers
>>>>>>> Halifax
>
>
> -----
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