Saline aquifer investigation

[Charlie]

Hi Carla,
Thanks for posting a good question.  Can you provide a bit of background/context to your project (details, location, geology, aims, objectives etc.) so that others can see what you are using PHREEQC to determine, and how?   I'm sure others will find this of interest and might be able to help further. 
Cheers

[Carla]

Thank you.

Yes , I say , because I'll need to make sure of your knowledge, because I am a beginner in this field .

My study aims to analyze the waters of a designated floodplain area of Nazareth and its surrounding, whose land until the century XVIII were covered by seawater. It is currently an area of intense farming. In addition to analyzing physicochemical surface water (rivers, lakes, ditches) and groundwater (wells, holes, springs) I have to find out the origin and fate, or rather draw a conceptual model of the area that includes three bodies of water (aquifers). The PHREEQC, this time, will serve to determine the saturation index of the water samples. I do not know if I should run another task in PHREEQC to help me in developing this model, so if anyone is experienced in this field, I appreciate advice and suggestions. Unfortunately, I have only analyzed a collection phase, which does not help me much, I think, but at least give an idea of the situation of the study area in order to draw attention to spatial errors present and/or future.

I'll await your suggestions. If you know of any literature that I should have access to help me finish this part of the thesis (water - rock ratio and conceptual model), I’ll be grateful.

Carla

[Charlie]

Some initial thoughts/questions that come to mind:

The area has intense farming - can you look at nitrate as a form of tracer?

What is the ionic strength/salinity/density of the waters?  I'm imagining that the groundwater salinity will be fairly high for your area.  For high ionic strengths, the activity expression equations may not be applicable and so you might need the Pitzer model equations instead.

Are you going to attempt inverse modelling at all?  This might provide some insight.

What data do you have of the aquifer lithologies?  Is there data for the aquifer mineralogy ?

Are each of the aquifers in continuity with each other (and the surface waters)?

Groundwater vectors can be inferred somewhat with reliable hydrochemistry data and SI analysis (groundwater evolution and weathering progression).  This might help if you haven't good data to contour the groundwater elevations.

Are you familiar with the SOLUTION_SPREAD function in PHREEQC?  This might save you a lot of time if you have a lot of water samples to process.

I have a couple of papers that might assist you (I will try to find others that are applicable too)
http://dx.doi.org/10.1016/j.chemer.2013.06.004
and
DOI: 10.1007/s11053-012-9180-6

Cheers, Charlie

[Carla]

Charlie Cheers

I appreciate your suggestions, which was unaware (Pitzer model, inverse modeling, SOLUTION_SPREAD function in PHREEQC).

I will look at my data and so that you can answer in order to give me more suggestions and advice in order to achieve complete quickly. (I found out mistakes, so do not know to respond).

The links you sent me relate to this article?
"Hydrogeochemical Modelling for Groundwater Aquifer in Neyveli, Tamil Nadu, India, Using PHREEQC: A Case Study»
I'll see if the college has access.

See you soon!

Carla

[Charlie]

Hi Carla,

Glad to be able to help.  Please post more information and hopefully this can stimulate more discussion and idea sharing.   The two papers I mentioned are:

Kumar et al, 2013. Hydrogeochemical zonation for groundwater management in the area with diversified geological and land-use setup. Chemie der Erde - Geochemistry. 73. 267–274

S. Chidambaram, P. Anandhan, M. V. Prasanna, AL. Ramanathan, K. Srinivasamoorthy and G. Senthil Kumar. (2012) Hydrogeochemical Modelling for Groundwater in Neyveli Aquifer, Tamil Nadu, India, Using PHREEQC: A Case Study. Natural Resources Research. DOI: 10.1007/s11053-012-9180-6.

I hope that you can access these - let me know if not.  If you have any good references that have used PHREEQC and you have used for your research, then please post the details for us to see!

Hope to hear from you soon,
Charlie

[Carla]

Charlie Cheers

I apologize for the delay .
Combined as follows my response to your questions .

The study area encompasses three bodies of water (Caldas da Rainha Nazareth Alpedriz , West Rim Undifferentiated Basins of Ribeiras West ) , despite having gone to examine one of the headwaters of the river belonging to Alcobaça other body of water called Estremadura Limestone Massif . It is considered the body of water : groundwater, reservoir , stream, river or canal , part of a stream , river or canal , a transitional water , stretch of coastal waters ( Decree 58/2005 , article 4 , paragraphs nn and oo ). These masses are shown contiguous. The general characteristics of the chips obtained Diagnostic Management of Water Resources of Portugal (2011) are as follows:
- The hydrological medium is porous to the three bodies of water with the exception of Estremadura Limestone Massif which is karst;
- The predominant aquifer water body in Caldas da Rainha Nazareth is: fossiliferous marine sands and continental sands of the upper Pliocene. For the Alpedriz: gresoso complex Cós-Juncal (lower Cretaceous ) and carbonate formations ( Upper Cretaceous ) . For West Rim Undifferentiated Basins of West Ribeiras is sand dunes and alluvial sands of the modern age, more or less marly limestones and marls gipsíferas Jurassic Kimmeridgiano. For the Estremadura Limestone Massif is carbonated formation of upper and middle Jurassic;
- The produtivividade in the same order described above is : 3 to 20l/s ; 0,44 to 15l/s ; 0 to 117L/s ; 0 to 20l/s;
- The transmissivity in the same order , is: 8 to 570m2/dia ; 4 to 156m2/dia; 1 to 3000m2/dia; 1 to 4800m2/dia.

The waters have a superficial route towards the floodplain of Nazareth (varzea da Nazaré), as this is a depressed area .

Analyzed within the VÁRZEA: 12 representative samples of the water Caldas da Rainha Nazareth (CRNaz) and 12 representative of the water mass of undifferentiated West Rim Bowls Ribeiras West (Orla). These were repeated in the 2nd phase three samples at each of the masses, and in 3rd phase only in the Rim. These repetitions were to later obtain water to perform other analyzes, such as trace elements and/or isotopes 18O and 2H. (I will not mention these phases, because not always been performed and the number was always very low)
These samples revealed in the 1st stage concentration of nitrates (NO3-) of: maximum value of 334,59mg/l (well) and minimum value of 0,37mg/l (well) in the water CRNaz with an average of about 62,25mg/l , lying 3 other sites with values greater than 50mg/l : hole with 50,08 mg/l, well with 256,87mg/l , hole with 72,32mg/l. Regarding Orla showed maximum value of 94,11mg/l (well) and value not detected in a ditch . From one phase to another crop was increased and those who decreased.
All these locations with high concentrations of nitrates are located in areas of intense agricultural activity particularly vegetables.
Regarding salinity :
- CRNaz : maximum 12,42‰ (hole) and minimum 1,93‰ (hole) with an average value of 5,11‰ ;
- Orla : maximum 10,14 ‰ (pond) and minimum 2,06 ‰ (river) with an average value of 6,60‰.

Outside the VÁRZEA also analyzed various types of water. Divide by the guidance for the floodplain. Thus, the northern lowlands were analyzed 12 samples belonging to the body of water CRNaz, 1 to the Alp and 14 to the Orla. This floodplain were analyzed: 3 Alp, 7 Orla and 1 MCE. The southern floodplain were analyzed: 2 of CRNaz and 23 of Orla.
The result on the concentration of nitrate (NO3-) in the northern part of the floodplain:
- CRNaz revealed a maximum of 336,12mg/l (well) and the minimum value 4,15mg/l (spring) , with an average of approximately 54,61 mg / l. Other locations revealed: 95,8mg/l (well) and 134,78mg/l (spring);
- In Alp was 3,17mg/l in a well;
- On the Orla , the maximum value was 31,07mg/l (well) and a minimum of 2,02mg/l (well) , with an average of 6,41 mg/l.
The result on the concentration of nitrate (NO3-) in the eastern part of the varzea:
- Alp showed maximum value 64,4 mg/l and minimum 3,01mg/l (all wells);
- Orla revealed maximum value 101,6mg/l (spring) and a minimum 3,27mg/l (well), with an average of 32,91mg/l;
- MCE revealed spring with 12,26mg/l .
The result on the concentration of nitrate (NO3-) in the southern part of the varzea:
- CRNaz showed well with 43,59mg/l and spring with 11,57mg/l;
- Orla revealed maximum value of 142,65mg/l (hole) and minimum not detected (well and hole) with an average of 29,16mg/l. There are other sites with greater than 50mg/l values ( DL n º 306/2007 of 27 August) : well with 131,89mg/l, hole with 64,48mg/l.
In relation to salinity , the Northern varzea:
- CRNaz : maximum 13,48‰ (pond) and minimum 2,37‰ (well), with an average value of 6,88‰ ;
- Alp : Well with 2,52‰ ;
- Orla : maximum 14,09‰ (spring) and minimum 4,56‰ (well), with an average value of 9,80‰ .
In relation to salinity, east of the varzea :
- Alp : Well with 9,75‰ , well with 3,47‰ and spring with 8,27‰;
- Orla : maximum 8,57‰ (hole) and minimum 3,54‰ (spring), with an average value of 5,32‰ ;
- MCE : rising to 7,92‰ .
In relation to salinity, the Southern varzea:
- CRNaz : well with 3.69 ‰ and spring with 5,12‰;
- Orla : maximum 13,31‰ (spring) and minimum 2,09‰ (well), with an average value of 6,17‰.

What value should I consider salinity as high?

I am inexperienced in PHREEQC. I'll start listening to suggestions and to apply in my work. I believe the information that I transmit to you is not enough for you, isn’t it? If so, tell me to delivery anything important for you can help me.

I've read the article that advised me. Enjoyed it is written in a simple and visible manner. Just could not understand where the authors values "phase mole transfer in flow path" were seeking. (Hydrogeochemical Modelling for Groundwater in Neyveli Aquifer, Tamil Nadu, India, Using PHREEQC: A Case Study)

I appreciate that you put me aware of what I should do and know to get a good thesis.

Thank you for all!

See you soon!

Carla

P.S.: I will read the others you suggest. Thank you.

[Carla]

Charlie
Ever encountered. What do you think of my data?
I'm just using PHREEQC solution without entering HCO3-  to determine the saturation index. Considers that it should also use Pitzer model, inverse modeling, SOLUTION_SPREAD function in PHREEQC? I count on your support, as in Portugal do not know anyone who can help me.
My thesis writing must be delivered before the end of March 2015. I have to use the mudflow program, will I be able to? I'm sorry, but I'm stressed because of time and I have discovered errors that forced me to re-do the thesis, hence the delay in my answers.
Thank you for listening, waiting for a response soon.
Greetings
Carla

[Charlie]

Hi Carla,

Thanks for continuing the discussion about your work.  Sorry that I haven't given a reply yet.  (I am trying to complete my thesis in next few weeks).  However, if you can be a little patient I might be able to offer more help later. 
I think your project can make good use of PHREEQC.  I would suggest making solution spread arrays for each of the water groups and first look at the saturation indexes for these waters.  Then you could even try to plot the SI for different mineral phases i.e. gypsum using software such as SURFER.  Try that see how you get on.

Cheers, Charlie

[Carla]

Thanks, Charlie Cheers.

Yes, I have patience. Incidentally I have a lot of data to change before entering the PHREEQC. My delivery of the thesis is bigger than yours. The other time, was in a hurry because I had to deliver a small part of the thesis to present the 4th of June. I still have much to do. Do not worry, first dispatch his thesis that after we talk.

Good work!

Success!

Carla