In fact, relationship will depend on the balance of T and R. If T--> R, impact of change will be obvious on several parameters of water quality.  Here, T and R both considered changed from normal of so-called climate change period. If T=R either higher or lower than normal, change in surface quality will not be perceptible. That is, if T and R both increase or decrease in the same proportion striking same balance as that in normal conditions. If R-->T, the water quality is expected to improve. In the present transitional conditions when T and R are not stablised, all three condition over a small period of time are expected to obtain giving no definite result.

Hi,

I think the attached files can give you some idea.

I think this paper will be beneficial for you. 

Water quality trend analysis in Eymir Lake, Ankara

http://www.sciencedirect.com/science/article/pii/S1474706510001002

In fact, relationship will depend on the balance of T and R. If T--> R, impact of change will be obvious on several parameters of water quality.  Here, T and R both considered changed from normal of so-called climate change period. If T=R either higher or lower than normal, change in surface quality will not be perceptible. That is, if T and R both increase or decrease in the same proportion striking same balance as that in normal conditions. If R-->T, the water quality is expected to improve. In the present transitional conditions when T and R are not stablised, all three condition over a small period of time are expected to obtain giving no definite result.

Thank you very much your  sharing and discussion Dr. A. Reza, Dr. F. Yenilmez and Dr. Mohammad. Your all ideas are valuable and I totally agree!

Dr. Mohammad, there are several variables beside two mentioned above (e.g. hydrological parameters) and they are not likely to change as others.  The challenge question here is how long is sufficient to evaluate these relationship? Some areas might have long observed data, while others have very short one (i.e. developing countries).

My next question is:

Do you think correlation values are suitable to evaluate the relationship between water quality and climate change? 

Best regards,

Hi Thanh,

I agree with Dr Mohammed, but i advice you to integrate historical data for climate, groundwater and population. In my mind a statistical study will be very useful.

Best for you

It is hard to tell how long is sufficient. Generally 30 to 40 year average prior to 1970 may be taken as normal. Since, 1980 onward you have data for as many years as you can will be good. Correlation analysis or Ch-square analysis or any other analysis that deals with co-variation is as good as any other.  Also incorporate variables suggested by Dr. Elgeettafi as population size refers to increased production and consumption and effluent finding ways into water-bodies. Surface-groundwater interaction may change some quality parameters of the surface water-bodies.

@Thanh, ALL,

Not sure it can be helpful for addressing your Q, but your understanding may improve through going to the attached discussion. 

https://www.researchgate.net/post/Will_climate_change_increase_the_water_quality_problem_across_the_globe

It is important to note hat before anything is:

When you analyze the data of hydrological stations, Fluctuations usually are seen during the study period. This oscillation depends not only on climate change, but also may be related to changes in land use. So in hydrological analysis in a watershed, both factors have to be evaluated with hydrometric data , because

I agree with the discussion of my colleagues.  I also would stress the importance of  the aspects raised by colleague Mohammad. However, it is important from the beginning to define the time span of the climatic change in concern. Is it thousands or hundred  or even in only one hundred year span. Based on the time span, the reliability of the available data can be judged.  

Dear colleagues,

I greatly appreciate your ideas. We also considered about the period of data, unfortunately we just have got data for a period of 40 years for climate and and water quality. The lack of data on land use change, groundwater, etc. are likely big challenges in developing countries. 

Our target is to analyze how changes in climate affect surface water, mainly river water? and whether research results are strong enough to lead to conclude the relationship between variables?.

We will think carefully what you suggested.

Meteorogical parameters that are determinant of climate change most importantly are temperatue,rainfall and sunshine hours variability among others..These parameters have been on steady rise(increase) over the years between 30-50 years especially in the semi hot equatorial regions .This will definately affect the warmth on surface water

I agree with the answers of previous researchers. I wish to add the following:

Changes in climate will surely affect the surface water quality (though there are other parameters besides climate parameters as pointed out earlier by others). But, climate change effect need not be instantaneous. That depends on many conditions. Most likely a change in climatic condition now will affect the quality of surface water in the future. Though it will affect in the present also but it might not be clearly perceivable. So, it is important to indentify where is the change point. Climate Data prior to that change point might give a good result when corelated with surface water quality of the present, I guess.

Dear Thanh,Climate change directly and indirectly affect on surface water quantity  as well as quality .

Hi,

Whatever statistical method you use you have to 1st decide if what you are mesuring does not have an induced effet  on the measure. Besides, keep in mind climate change affects water temperature that in term will affect climate.

Surface water quality is vague, should you choose surface water tempeture, one as to remember, as cited by others, that there are many factors that can affect water temperature. But the distance from main fluxes that can change temperature is key to record in that view.   

Hi, to the question you asked: ''Do you think correlation values are suitable to evaluate the relationship between water quality and climate change?''     ---  I think that yes, but only when the trends are stable, in phase and simple.

It may be important, before looking for direct correlations, to assess the regularity of processes involved in water quality. Some processes are non-linear and likely to be triggered by climate changes (warming or not, anthropogenic or not).

For example, mass movements of unstable slopes are likely to be more recurrent when precipitations increase, and would result in catastrophic sediment and nutrient input in some channels. Old sapprolith mountain environments may be especially vulnerable to topography readjustment by mud flows while water table rises and loess plateaus may be especially affected by bank erosion while river morphology readjusts to new stream discharge. This would directly and non-linearly affect water quality in China until a new steady-state is reached (which could be long/never happening).

Another example is found in permafrost areas, where the temperature itself triggers many catastrophic erosion event (thermo-erosion). After studying the impact of permafrost degradation on arctic river biogeochemistry, Frey and McClelland found that ''Changes in river export of organic matter, inorganic nutrients, and major ions as a consequence of degrading permafrost as well as other drivers are likely to differ markedly across spatial scales and geographical regions.''  See attached. These process are likely to happen as well in mountain permafrost of Himalaya and Mongolia, and affect the Chinese stream water quality they are feeding.

So, I'd be careful with statistics interpretations, and would reserve it for closed or semi-closed geosystems where the trend of only very few values are put together at a determined scale. I don't think they would allow to effectively evaluate the relationship and make any prediction but still, they could provide the base for questioning further, or let's say they would serve as a wake up call if showing any relation.

Cheers!!!

Glacier melting is also another obvious effect of climate change in water quality.   

As said, climate change studies require long time series data, and thus, an adequate time and space resolution of ocean data is required to portray the trends, at the same time reduce the noise due to high frequency processes. Yes, water parameters at the surface could be related to climate changes considering the fact that the surface water are influenced by atmosphere processes through the transfer of momentum and matter, and bearing in mind that the atmosphere has a strong sign of climate changes, and the variables suggested here (rainfall and air temperature) are the better indicators of such changes. Apart from this the ocean surface is representative of the mixed surface layer, a much deeper portion of the ocean than solely the interface between atmosphere and ocean. This last argument suggest that the noise due to high frequency processes may be reduced by mixing processes that takes place at the upper layer. Lastly, perhaps considering the changes or gradients of the surface parameters, in adequate scale, may render a good relationship with climate variables.

Dear Colleagues, 

Thank you very much for your interest in my question and sharing very diverse points!

I totally agree with your answers however, in fact we are not able to comprise every parameters and aspects to evaluate the relation (climate change vs water quality) even though they have actual interactions among parameters.

After considering your all comments and ideas seriously, my direction is being shaped.

Many Thanks,

Thanh

Dear Thanh ,

I send u one paper related climate change and surface water quality. Hope, may be this paper help you.

You will find it nearly impossible to sort out the small changes due to climate change from the larger changes due to the manner in which society interacts with the surface water.  If the system was pristine and there were no societal contributions it would make sense to have this discussion, but I suspect the dominant contribution to perturbing the system in many surface waters will be the direct point and non-point contributions from near bank activities.  I suspect this will completely overwhelm any effect of climate change.

I agree totally with Adrian Hanson. There are some global  models that take into account important drivers like population growth, Agricultural activity, climate change, altering streams by building reservoirs, etc....

Look for the NEWS models (http://marine.rutgers.edu/globalnews/documents.htm) for more statistical models or for a more process-based model (http://dspace.library.uu.nl/handle/1874/298665)

Have you tried environmental isotopes (18-O &D) comparing old groundwaters and surface water (rain) signatures?   

Dear colleagues,

Thank you very much for sharing your ideas.

We will try to involve as many factors as possible in your assessment.

Thanh,

Climate change has relationship with water quality. But the relationship is rather complicated. Climate change factor contribution to water qulity demage is rather less than social economy activities.