In Siwa Oasis there are many wells. We want to know the source of water that feeds these wells Is this possible through isotopes for example
The search for ground water - water enclosed in pores of soil or bed rocks can be found using Remote sensing techniques.
The sub surface geologic elements forming aquifers have some surface expressions which can be discerned by remote sensing techniques.
This techniques are complement and supplement the existing techniques of hydro-geological and geo-physical techniques as explained by Sir William F Hansen above and are not replacement for these techniques.
Isotopes have also been used for knowing the movement and distribution of water processes- as heavy stable isotope of water molecule and radio isotopes help in detecting the evidences of presence of water and the residence time.
Stable and radio- active isotopes are found to be effective in ground water recharge, interconnection between aquifers in hydro- logical assessment and investigations and have been found to be cost effective also.
It would be best first to consult with geologist/hydrogeologist and/or compile any existing or available information on geology, topography, stratigraphy, water flow and quality tests from wells. Water tracing can be done over short distances, but difficult to trace water long distances unless it is flowing in underground streams or areas of concentration. Compile advice and technical information before considering trying to trace water, or determine its source. Hydrogeologists have various tools and techniques, but their application to conditions such as desert oasis may be a challenge to fit the circumstances. Experienced well drillers may have useful information to apply to subject. As with many topics, selecting technical/field expert(s) is likely to save funds and effort in the long run, possibly identify options, and be more effective in producing results. Where source waters come from dispersed landscape sources, it may be difficult to trace until the waters collect in some recognizable feature, such as aquifer, fault zone, permanent water table, spring or stream indicators.
The search for ground water - water enclosed in pores of soil or bed rocks can be found using Remote sensing techniques.
The sub surface geologic elements forming aquifers have some surface expressions which can be discerned by remote sensing techniques.
This techniques are complement and supplement the existing techniques of hydro-geological and geo-physical techniques as explained by Sir William F Hansen above and are not replacement for these techniques.
Isotopes have also been used for knowing the movement and distribution of water processes- as heavy stable isotope of water molecule and radio isotopes help in detecting the evidences of presence of water and the residence time.
Stable and radio- active isotopes are found to be effective in ground water recharge, interconnection between aquifers in hydro- logical assessment and investigations and have been found to be cost effective also.
Well,
the links below can be useful
Sincerely
Conference Paper APPLICATION OF ENVIRONMENTAL ISOTOPES TECHNIQUE IN GROUNDWAT...
https://www.researchgate.net/publication/303913759_Hydrogeochemical_evaluation_of_the_groundwater_within_Abu-Jir_Fault_Zone_Hit-Kubaisa_region_Central_Iraq?
Resistivity survey is the suitable way to know the source of groundwater, later by pumping test to check the yield of water.
Source of water to recharge groundwater bodies (aquifers) can be rainfall; or river or stream water (effluent streams); or another aquifer (aquifer to aquifer interaction). To identify the source of recharge to groundwater then one has to have the knowledge of local geological and hydrogeological setup. Surely the isotope method (tritium method is widely used) can help in identifying the different sources of water recharging groundwater.
using landsat-8 image and ArcGIS to
know the source of water in a well
I think your explanation is about the use of remote sensing techniques, and the tracer method is the best way to know the source of feeding for those wells, and do not forget the economic feasibility of those techniques.
General water quality measurents, ions, and isotopes can all help. Knowing the geology of the area may help idemtify which units are contributing aquifers based on major ions, tritium can help date water, sources of contamination (nitrate, pesticides) may indicate the amount of surface recharge and possible locations of contamination based on stable isotopes.
Remote sensing technique using satellite images will give the areas which are potential for groundwater exploration and not the source of groundwater. As already mentioned, integration of hydrogeological knowledge and results from isotope investigations will give the source of water in the wells.
First you must locate the water influx point/points in the well, for the identification of aquifer formations, layers.
Hello Sabry,
The water resource that supply any well may be the underground water or from any underground flowing source of river/stream. To confirm the same, remote sensing methodology will come to be the best.
Please understand the Hydrological cycle and Groundwater Hydrology before answering. In majority areas, rainfall is the primary source for groundwater recharge. To say that one can find out the source of groundwater through remote sensing is to me the height of exaggeration !!!
Hi, Sabry,
Normally what you want to know if the water is recent or ancient, what means, if it is dependent of rain or not. This has implications for the availability and also for the possibility of contamination.
Tritum, 3H, the heaviest hydrogen isotope, has a half life of about 12.3 years, is the best one to differentiate such waters.
Naturally occurring tritium is extremely rare on Earth. Trace amounts are formed by the interaction of the atmosphere with cosmic rays.
So, tritium is formed while the water is in contact with air. as soon as the water enters the earth tritium only decays and reduce its mass to half of the suface's standard value after 12.3 years, to 1/4 in 24.6 y, 1/8 in 36.9 y, 1/16 in 49,2 y, an so on, in such a way that you even can say exactly the how long ago the water was on the surface.
Because the amount of tritium constantly formed is very little, you have more or less 50 years as the limit to indicate. Older than 50 years or younger than 50 years. Half a century is a very long time for a human's life.
About the geological environment in which the water was formed, there are many chemical analysis that are performed that, combined with the geological description of the region, permit to say the geological provenance too. Simple examples are magnesium water, carbonic (gas) water, sulfurated waters, that may indicate magmatic chamber or a volcano near by.
Hope to have helped.
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