Thanks Yajun Li. I have put a link to the model in the description below the video. Let me know what you do with it. All the best, Andreas

Glad it was helpful Ankit! All the best, Andreas

@Diclofenac_ Thanks for your kind words & congratulations for finishing your BSc. I hope you find an interesting job. Hydrogeology is a massive subject, so keep reading and talk with the older generation... Also after a few years consider an MSc if you want to specialize. All the best, Andreas

You are welcome Noor! If you want to play with the Excel model, there is a link in the description under the video to download it. All the best, Andreas

Glad you like them Lila! Each video takes about a week, mostly for planning & thinking how I'm going to present the ideas. I have already given the lectures, but condensing it all into an interesting video is another story... All the best, Andreas

​@@GeosearchInternationalI have been binge watching your videos, so you certainly have succeeded at making them interesting. I am moving to a homestead and you have given me the idea to invest in a used a earth ground tester to identify the aquifers

That sounds exciting! Have a look at my video on Groundwater Exploration Strategy. Geophysical surveys are just a small part of the process of looking for groundwater. Wish you the best, Andreas

You're welcome!

Glad it was helpful Mostafa! All the best, Andreas

Thanks Fuzel! All the best, Andreas

Hi Roberto, Thanks so much for finding the copy-paste error in the Unconfined model! So many people have watched the video and you are the first to spot it. I have updated the unit - of course K is in m/d. There are two different models: 2D-SS-CON GW Model V1.xlsx is for steady state confined conditions, and 2D-SS-UNC GW Model V3.xlsx is for steady state unconfined conditions. The unconfined formulas are more complicated as the aquifer is being dewatered, and there are separate calculations being carried out in a hidden sheet called "V". All the best, Andreas

Hi Mahdi, Sorry I don't have any videos about the equations. As I mentioned in the video, this Excel model is based on one made by Carlos Molano, so I don't have all the references for it. The equation for confined aquifers does not need to be changed. If you remove all the pumping wells and the recharge, you will end up with a flat surface as the heads are controlled by the outer boundary cells which are all set to 100m (you can change this if you like). Once you add pumping wells, recharge wells or general recharge the heads will be recalculated as long as you have iterations enabled in Excel. For unconfined aquifers you cannot use this model. Please see my video Steady state in pumping wells: kzfaq.info/get/bejne/b72dntiY3pm8lIU.html You can download the unconfined model in the description below the video. All the best, Andreas

A good question, and I think the key issue is that any model is only as good as our conceptual model of the world. If we stick in a constant head boundary, it will supply an endless amount of water to the model, so we need to look at that in the water balance and ask ourselves if that body of water can really supply so much water without a reduction in head / drying up. If you are pumping next to a big lake or river, maybe a constant head boundary is OK. The key is to look carefully at the water balance. As for tik tok I don't watch it, but I have always supported the concept of work hard - play hard! All the best, Andreas

Hi James, Glad you liked the video. Sorry, I have not made any videos so far on groundwater modelling. Maybe later? First I need to do more on the simple tools like flow nets. All the best, Andreas

Hi David, I just downloaded 2D-SS-CON GW Model V1.xlsx and it still works fine. Please check your Excel Options. Under Formulas - Calculation options, you need to have Workbook Calculations set to Automatic. Also enable Iterative Calculations and set them to Maximum Iterations 1000 and Maximum Change 0.00001 When you add a new well in the Wells sheet, it should show up immediately if the number is high enough (eg 10,000 m3/d). Hit F9 to repeat the calculations. Hope that solves the issues. All the best, Andreas

Got it to work - had to allow iterative calculation in the excel settings first :)

edit: now the model changes with different well settings/positions, but it creates a "bowl shaped" drawdown even without any wells.

Hi @Diclofenac_ Initially you have the model that I created with 2 wells, so there is a cone of depression in the centre. Then you deleted the wells, so Excel will start to iterate. With each iteration the model will increase the heads in the cone of depression to slowly reach the 100m head around the model. If you have set Excel up for 1000 iterations, you still end up with about 1 or 2 cm drawdown in the centre after 1000 iterations - the bowl shape you mentioned. Just hit the save button a couple of times and after a few more iterations it should approach the 100m of head in all cells. All the best, Andreas

Hi Kaleem, There are two purposes for step tests: 1) Calculate the well efficiency, V = BQ/(BQ+CQ2), so that we can see if the well has been designed and constructed properly. 2) Decide what discharge rate to use for the long-term pumping test, so that the well is stressed as much as possible without dewatering it. All the best, Andreas

Thanks a lot.

Welcome Kaleem! All the best, Andreas

Hello sir, Could you share the excel sheet for step test. Thank you.

You will have to wait till the video, as it needs to be explained to be useful. All the best, Andreas

Thanks

Hi Jhan, If you have any questions please use this comments section as I am bad at answering emails - get too many every day and I don't have time to read them. All the best, Andreas