Groundwater Modeling Concepts

[@namonyesam5198]

So insightful, thank you

[@debrunyon8039]

Excellent overview of groundwater modeling! Thank you very much!! Sure wish I could take your full course.

[@hsahil_10]

Thank you Sir. Simple and excellent explanation.

[@lalualiyyatirangga6466]

Thank you for your insight! I have several questions related to the data collection steps:
1. If we want to conduct regional scale groundwater modeling (watershed scale), what is the average spatial resolution required for elevation data? Is SRTM data with a 30 m spatial resolution representative enough to be used as digital elevation data in our model?
2. Related to question no. 1, I had an issue when I tried to delineate a catchment and generate streams based on a GIS approach using SRTM data. The location of higher-order streams, which I assumed to be rivers in my model, did not spatially align with the real rivers that I had delineated using Google Satellite aerial photos. Some segments of the real rivers were not located in valley topography on the SRTM data. How should I deal with this issue? Which river data should be used?
3. Are elevation data (river stage, lake stage, water table elevation from dugwell) sourced from handheld GPS measurements representative enough to be used? Regarding the third question, is the accuracy level of handheld GPS tolerable in the model? If not, is there any other more practical and low-cost method/tool?
4. Is there a practical measurement method or instrument to measure riverbed sediment thickness and hydraulic conductivity? How can this method be applied to large and deep rivers?
Thank you.

[@groundwatermodeling]

1) It depends on your grid resolution, but I would imagine that 30m SRTM data should be adequate in most cases.
2) Yes, is you use an automated stream-delineation method, the location of your streams may or may not match your basemap if the resolution of the grid you use for the delineation is too coarse. But for use with GMS, you turn on your basemap in GMS and then manually digitize the streams in the map module by tracing the stream locations on the basemap. You could then use a DEM to interpolate the stream elevations or you could assign them manually to the nodes in the stream network.
3) A hand-held GPS should be plenty accurate.
4) I do not know of any practical way to accurately and cheaply measure riverbed thickness and hydraulic conductivity. The typical approach is to estimate the values. All that really matters in the end is the resulting conductance values. You can examine gains or losses from streams to back-calculate or calibrate your river conductance. Also, in my experience, the model results are generally not highly sensitive to conductance.

[@arifgunawan7772]

fabulous

[@qadrmuhamad6706]

🎉

[@wessamdaoud6760]

Sir
The following message appears when running modflow
What is the solution pleaseError_ file mf2kerr.p00

[@excelvbaprimer]

Can you give me more detail?

[@wessamdaoud6760]

@@excelvbaprimer sir Do you have an email to send the error message Thanks for your attention

[@graphics2460]

it's urgent