It depends on a lot of factors. Water quality will not be affected by depth if the reservoir is located in the same geological structure. If the geological structure of the water table varies a lot, then the quality of the water will be different depending on the depth.

Regards

Sir, If there is saline in groundwater and suitable water found in more than 200 meters depth. Is the geological structure is similar or not?

Depth is a key factor affecting water quality through two concepts. the first one applies to the one water-bearing horizon, in which the groundwater has a piston flow regime, so the water salinity will be increased by depth. The other concept applies to the multi aquifers in which the groundwater do not hydraulically connected, they will have varied qualities and their salinities may abruptly increase with depth.

The ground water quality is dependent on the aquifer geometry as well as the geological formations. Multi aquifer systems show different water quality because the source/recharge area. Even in the shallow/ unconfined aquifer the water quality varies with depth. Also the water quality parameters you aim for are

important. Some of the parameters may vary more than other parameters.

In case of coastal aquifers the saline and the fresh aquifers occur under a delicate hydraulic equilibrium. Several fresh and saline aquifers do occur, each fresh aquifer is different from the other fresh aquifers in their water quality.

Aishik Debnath ..

Agree with all the discussion above.

Depth is a very important parameter in water quality analysis. water quality may change significantly with depth in the same location.

You can refer to some of my work also to understand that in detail.

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Article Assessment of groundwater quality scenario in respect of flu...

Article Geochemical and geostatistical appraisal of fluoride contami...

Article An evaluation of irrigation water suitability in the Dwarka ...

Without information of depth of the water sample for quality Analysis, is difficult to measure its quality because depth is an important factor and may affect or vary from depth to depth. I think without consider depth the results will be no reliable. Furthermore I also endorse the statement of Raju Thapa.

In my studies in Turkey I determined that, quality changes can be neglected for shallow and uniform aquifers at depths (if not directly affected by a pollutant). However, the situation is different in aquifers represented by thick and separate lithology. In addition, the situation becomes even more complicated if different layers are recharged from different sources. Therefore, this issue is site specific. If insitu parameters such as EC, TDS, pH, T do not change much with depth , it can be sampled sparsely. If not, more frequent. You can use a special sampler to get water from various depths.

If depth is one of the parameters you want to analyse then you need a sterilized tape measure with a steel bucket to draw water at different depths of the well. Once you analyse then you can compare. The depths are high during rainy season but very shallow during dry season.

It would be interesting to note that the iron content in ground water varies with respect to depth as well as laterally.

The metallic well casing pipes influence the quality of the sampled water, particularly if they are old. This is to be borne in mind.

How deep? The primary benefit of depth analysis is the ability to differentiate geochemical facies of water table aquifers vs. a variety of semi-confined and confined aquifers. For example, recharging water table aquifers generally flow dilute calcium-magnesium bicarbonate or calcium sulfate water types. Semi-confined aquifers ( a little deeper) in recharge zones, tend to flow with sodium sulfate type waters until such depths that bacteria consume all the sulfate. Beyond that depth, water types tend to be dominated by sodium bicarbonate and sodium chloride water types. Bicarbonate concentrations there tend to increase in the direction of flow as a result of bacterial respiration.

Chemical parameters in discharging regimes can have very different geochemical fluid facies at a similar spectrum of depths. For example, in the shallow hyporheic zone, you are may have alluvial aquifer and basinal fluid mixtures that have an increasingly saline basinal fluid chemistry with increasing depth. And in coastal zones, mixing zone gradients will vary with both depth and lateral distance from the sea/lake...etc, so chemistry is likely to differ laterally a equivalent depths.

But beware, if your are working with water wells not specifically designed as monitor wells, you are likely to have mixed fluid sources in the water column to start with. The only way to deconvolve that is to map fluid chemistry in wells of similar total depthso even attempt mapping lateral gradients along any recharging or discharging flow path.

Groundwater means water sample from dug wells, deep wells, bore/drill wells. hand pumps and many other water systems. Ground water chemistry indicate presence of ionic concentration in water along with pH specific conductivity, color, taste, smell , turbidity. In addition to these bacteriological parameters also. Depth is variable, varies with seasons. It is difficult to know correct depth of pumping water. However this is very interesting question and need to be discussed in detail.

The well construction data as well as the drilling data and lithological logs provide very useful information in this regard. The electrical logs help much as well.

I think so, it is should concerning the depth for GQ.

I think you mean, does the intake depth of the device collecting the sampled water matter (is it relevant) in a well. The answer is yes unless the well is completely mixed and depth-independent (chemistry) or the well is dominated over much of its length by water from inflow from one particular unit-in, creating one vertical flow cell, in which case there will likely be an outflow unit that is receiving the inflow water.

Ground water quality may not be related to depth. It is difficult to know at what depth water sample is coming. Ingeneral depth of sampling is not mention in report. Depth is variable parameter. Hot spring/ cold spring usually collected from the sourse.

This can be easily experimented and report will be well documented and useful for others.

The geometry and depth of water table is affected by the surface of the land, which lies above it. The shape of water table is convex under elevated surface and concave under depressed surface. Groundwater, which is under the water table originates from seepage orchestrated by precipitation through surface of soil. Hence, depending on the lithological units, and the alternate sequence of argillites and arenites therein, the contamination of groundwater can be directly linked with the depth of extraction.

Yes, depth is a factor....Consider that the upper 300 m may contain potable water. Within that 300 m may be several different geologic units that react differently with groundwater. Further consider that groundwater flows along unique paths with conceivable, longer flowpaths with depth.

Water logger with micro probe for dermining the water quality and depths along with other parameters are widely available in market.

This is very simple experiment. Take observations and report data. And proudly conclude the results.