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A Question about a Spring (water)

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  • 15-01-2012 2:37pm
    #1
    slowburner
    Moderators, Science, Health & Environment Moderators Posts: 5,218 Mod ✭✭✭✭


    I have a spring very close to the house which flows out of the side of the hill.
    I am not sure what else to call it as it is probably not a true spring which has an unvarying flow rate and it can dry up altogether.
    I suspect that it is a direct product of the changing levels in the water table because its flow varies.

    The rate of flow doesn't seem to have a direct relationship with the amount of rainfall. In other words; if there was say, two or three days of intense rainfall, this might not have an effect on the flow for a couple of weeks.
    Or it could have a steadyish flow even after a dry spell.

    Obviously, it takes time for water to percolate down through the heavy soils here but the flow rate doesn't seem to follow the pattern that you would expect from a watercourse that is exclusively rain fed.
    I suppose in this respect, it could be called a spring?

    So what I would like to know is this: how can I figure out when the water which is coming out of the spring, fell as rain?
    I have a sneaking suspicion that the outbursts and droughts might take a lot longer to show up in the spring than would be observable in an open watercourse and events might be delayed by many weeks rather than days.
    The factor which makes me suspect this, is the temperature of the water.
    2010 in particular, was confusing. When heavy rain fell overnight on a heavy blanket of snow there was severe flooding in this locality.
    But the odd thing was that when the spring began to flow heavily, the water was so warm that it gave off steam.
    I have a sneaking suspicion that the water which flowed on this occasion was not the water from the snow melt.
    So I wonder if this particular temperature 'event' indicates that fresh, cool water coming into the water table somehow forces out warmer water which has been warmed underground.

    I am hoping that I can devise some sort of an analytical system to figure out how long the water has been sitting underground, based on temperature readings.
    The theory being that the warmer the water, the longer it has been underground.
    Any thoughts?


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    #2
    NotCarrotRidge
    Registered Users Posts: 160 ✭✭NotCarrotRidge


    slowburner wrote: »
    I have a spring very close to the house which flows out of the side of the hill.
    I am not sure what else to call it as it is probably not a true spring which has an unvarying flow rate and it can dry up altogether.
    I suspect that it is a direct product of the changing levels in the water table because its flow varies.

    The rate of flow doesn't seem to have a direct relationship with the amount of rainfall. In other words; if there was say, two or three days of intense rainfall, this might not have an effect on the flow for a couple of weeks.
    Or it could have a steadyish flow even after a dry spell.

    Obviously, it takes time for water to percolate down through the heavy soils here but the flow rate doesn't seem to follow the pattern that you would expect from a watercourse that is exclusively rain fed.
    I suppose in this respect, it could be called a spring?

    So what I would like to know is this: how can I figure out when the water which is coming out of the spring, fell as rain?
    I have a sneaking suspicion that the outbursts and droughts might take a lot longer to show up in the spring than would be observable in an open watercourse and events might be delayed by many weeks rather than days.
    The factor which makes me suspect this, is the temperature of the water.
    2010 in particular, was confusing. When heavy rain fell overnight on a heavy blanket of snow there was severe flooding in this locality.
    But the odd thing was that when the spring began to flow heavily, the water was so warm that it gave off steam.
    I have a sneaking suspicion that the water which flowed on this occasion was not the water from the snow melt.
    So I wonder if this particular temperature 'event' indicates that fresh, cool water coming into the water table somehow forces out warmer water which has been warmed underground.

    I am hoping that I can devise some sort of an analytical system to figure out how long the water has been sitting underground, based on temperature readings.
    The theory being that the warmer the water, the longer it has been underground.
    Any thoughts?

    I'm not a hydrogeologist, so I couldn't tell you. Why don't you contact a hydrogeologist in the GSI, or one of the universities?


  • Options
    #3
    slowburner
    Moderators, Science, Health & Environment Moderators Posts: 5,218 Mod ✭✭✭✭slowburner


    Because this way is more interesting ;)


  • Options
    #4
    NotCarrotRidge
    Registered Users Posts: 160 ✭✭NotCarrotRidge


    slowburner wrote: »
    Because this way is more interesting ;)

    Well in that case, good luck with it.


  • Options
    #5
    Subpopulus
    Registered Users Posts: 837 ✭✭✭Subpopulus


    slowburner wrote: »
    I have a spring very close to the house which flows out of the side of the hill.
    I am not sure what else to call it as it is probably not a true spring which has an unvarying flow rate and it can dry up altogether.
    I suspect that it is a direct product of the changing levels in the water table because its flow varies.

    The rate of flow doesn't seem to have a direct relationship with the amount of rainfall. In other words; if there was say, two or three days of intense rainfall, this might not have an effect on the flow for a couple of weeks.
    Or it could have a steadyish flow even after a dry spell.

    Obviously, it takes time for water to percolate down through the heavy soils here but the flow rate doesn't seem to follow the pattern that you would expect from a watercourse that is exclusively rain fed.
    I suppose in this respect, it could be called a spring?

    So what I would like to know is this: how can I figure out when the water which is coming out of the spring, fell as rain?
    I have a sneaking suspicion that the outbursts and droughts might take a lot longer to show up in the spring than would be observable in an open watercourse and events might be delayed by many weeks rather than days.
    The factor which makes me suspect this, is the temperature of the water.
    2010 in particular, was confusing. When heavy rain fell overnight on a heavy blanket of snow there was severe flooding in this locality.
    But the odd thing was that when the spring began to flow heavily, the water was so warm that it gave off steam.
    I have a sneaking suspicion that the water which flowed on this occasion was not the water from the snow melt.
    So I wonder if this particular temperature 'event' indicates that fresh, cool water coming into the water table somehow forces out warmer water which has been warmed underground.

    I am hoping that I can devise some sort of an analytical system to figure out how long the water has been sitting underground, based on temperature readings.
    The theory being that the warmer the water, the longer it has been underground.
    Any thoughts?

    Water does not warm up underground. The longer the water has been underground the colder it will be since the water will have been in contact with cold rock for far longer. Speleologists use temperature measurements of springs and risings to get indications of the geology of the rock that the water flows through. Springs that have a stream input and that spend much of the time flowing between the sink and rising in open air filled passage will be much warmer than springs that have had water sitting in small cracks for a long period of time. The water you saw steaming might have only been 6 Celcius (remember that most moving surface water is about 13 degrees on average) but if the surrounding air was -2 then it would steam.

    Chemical analases are often made of springs, different quantities of diffused minerals indicate how long water has been in a particular system.

    Frequently water flow readings from springs are tallied against rainfall readings of the catchment. Springs respond to rainfall differently. In winter the water quickly reaches the water level since the ground is ususally saturated or close to it. In the summer the drift is less waterlogged and soaks the rainfall more rapidly. Rainfall may also be used to recharge an aquifier rather than rising out of the ground at the spring. It's very difficult to predict how springs react to rainfall. Springs close to the coast may also be affected by the tide and flow only at high tide.

    Where exactly is this spring and what is the surrounding geology? Is it a limstone area?


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    #6
    slowburner
    Moderators, Science, Health & Environment Moderators Posts: 5,218 Mod ✭✭✭✭slowburner


    Thanks for that.
    There is no limestone, that's for certain.
    The spring is on one of the many hillsides around Avoca, Co.Wicklow.
    The geology here is notoriously complex, but the relevant area is a deposit of granite erratics underlain by gossans, decaying chalcopyrite and slate, all interspersed with remnants of mining and quarrying (both ancient and recent) and a bit of whatever you're having yourself.
    Very complicated geology.


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    #7
    Coles
    Registered Users Posts: 1,020 ✭✭✭Coles


    It would be very easy to measure changes in the flow with a simple cipoletti weir/V-notch weir, but it takes a lot of discipline to record your measurements. Might be interesting to compare how the flow reacts to rainfall events etc...


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