UZF-GWET term on volume budget #1904

martclanor · 2024-06-26T14:53:14Z

martclanor
Jun 26, 2024

Hello all. Perhaps a long shot but I was wondering if anyone can help me make sense how come the UZF-GWET is an inflow instead of an outflow. What does that mean in practice? What could have possibly caused this?

This is the Volume Budget section of my LST file (I'm also attaching the file itself, in case it can help test_uzf.zip):

  UZF BUDGET FOR ENTIRE MODEL AT END OF TIME STEP    1, STRESS PERIOD   1
  ------------------------------------------------------------------------------

     CUMULATIVE UZF      L**3       RATES FOR THIS TIME STEP      L**3/T
     ------------------                 ------------------------

           IN:                                      IN:
           ---                                      ---
                 GWF =           0.0000                   GWF =           0.0000
        INFILTRATION =    41852715.4406          INFILTRATION =      114664.9738
             REJ-INF =           0.0000               REJ-INF =           0.0000
                UZET =           0.0000                  UZET =           0.0000
             STORAGE =           0.0000               STORAGE =           0.0000
           AUXILIARY =           0.0000             AUXILIARY =           0.0000

            TOTAL IN =    41852715.4406              TOTAL IN =      114664.9738

          OUT:                                     OUT:
          ----                                     ----
                 GWF =    43640277.6320                   GWF =      119562.4045
        INFILTRATION =           0.0000          INFILTRATION =           0.0000
             REJ-INF =     2047538.9869               REJ-INF =        5609.6959
                UZET =           0.0000                  UZET =           0.0000
             STORAGE =           0.0000               STORAGE =           0.0000
           AUXILIARY =           0.0000             AUXILIARY =           0.0000

           TOTAL OUT =    45687816.6189             TOTAL OUT =      125172.1003

            IN - OUT =    -3835101.1783              IN - OUT =      -10507.1265

 PERCENT DISCREPANCY =          -8.76     PERCENT DISCREPANCY =          -8.76



  VOLUME BUDGET FOR ENTIRE MODEL AT END OF TIME STEP    1, STRESS PERIOD   1
  ---------------------------------------------------------------------------------------------------

     CUMULATIVE VOLUME      L**3       RATES FOR THIS TIME STEP      L**3/T          PACKAGE NAME    
     ------------------                 ------------------------                     ----------------

           IN:                                      IN:
           ---                                      ---
              STO-SS =           0.0000                STO-SS =           0.0000     STORAGE                          
              STO-SY =           0.0000                STO-SY =           0.0000     STORAGE                          
                 WEL =           0.0000                   WEL =           0.0000     WEL_KLEINE_ONT                   
                 WEL =           0.0000                   WEL =           0.0000     WEL_GROTE_ONT                    
                 WEL =           0.0000                   WEL =           0.0000     WEL_DWATER_ONT                   
                 DRN =           0.0000                   DRN =           0.0000     DRN                              
                 DRN =           0.0000                   DRN =           0.0000     DRN_LANDBOUW                     
                 DRN =           0.0000                   DRN =           0.0000     DRN_MAAIVELD                     
                 RIV =   914174904.9653                   RIV =     2504588.7807     RIV_VL                           
                 RIV =   767810433.9801                   RIV =     2103590.2301     RIV_NL                           
                 CHD =     6201944.7010                   CHD =       16991.6293     CHD                              
                 LAK =           0.0000                   LAK =           0.0000     LAK                              
           UZF-GWRCH =    43640277.6320             UZF-GWRCH =      119562.4045     UZF                              
            UZF-GWET =   112491297.3466              UZF-GWET =      308195.3352     UZF                              

            TOTAL IN =  1844318858.6250              TOTAL IN =     5052928.3798

          OUT:                                     OUT:
          ----                                     ----
              STO-SS =           0.0000                STO-SS =           0.0000     STORAGE                          
              STO-SY =           0.0000                STO-SY =           0.0000     STORAGE                          
                 WEL =      549432.8184                   WEL =        1505.2954     WEL_KLEINE_ONT                   
                 WEL =     8619200.0000                   WEL =       23614.2466     WEL_GROTE_ONT                    
                 WEL =    14852834.5884                   WEL =       40692.6975     WEL_DWATER_ONT                   
                 DRN =    29817881.2571                   DRN =       81692.8254     DRN                              
                 DRN =  1457357609.6451                   DRN =     3992760.5744     DRN_LANDBOUW                     
                 DRN =     7578019.2530                   DRN =       20761.6966     DRN_MAAIVELD                     
                 RIV =    56810703.1939                   RIV =      155645.7622     RIV_VL                           
                 RIV =   259600781.9585                   RIV =      711235.0191     RIV_NL                           
                 CHD =     5914667.4119                   CHD =       16204.5683     CHD                              
                 LAK =           0.0000                   LAK =           0.0000     LAK                              
           UZF-GWRCH =           0.0000             UZF-GWRCH =           0.0000     UZF                              
            UZF-GWET =           0.0000              UZF-GWET =           0.0000     UZF                              


           TOTAL OUT =  1841101130.1262             TOTAL OUT =     5044112.6853

            IN - OUT =     3217728.4988              IN - OUT =        8815.6945

 PERCENT DISCREPANCY =           0.17     PERCENT DISCREPANCY =           0.17

And also if

UZF BUDGET: OUT: GWF = VOLUME BUDGET: IN: UZF-GWRCH = 119562.4045

then where is:

VOLUME BUDGET: IN: UZF-GWET = 308195.3352

in UZF BUDGET: OUT?

langevin-usgs · 2024-06-26T19:41:19Z

langevin-usgs
Jun 26, 2024
Maintainer

Not sure what is going on here, but i see in your list file that a bunch of cells went dry. In theory, that might be okay if rewetting is on and the answer is good, but in practice a bunch of dry cells is not ideal. I'd suggest you turn on NEWTON and try solving this problem differently. The positive UZF-GWET term is strange, and something doesn't seem right so if that persists we should have a look.

2 replies

martclanor Jun 27, 2024
Author

Thanks a lot already for answering. For the moment, I couldn't come up with a converging solution with the NEWTON turned on for this steady-state model. However, I also have a transient version of this model which is already run with the NEWTON turned on and where this positive UZF-GWET issue persists for all stress periods. Can you also maybe have a look on this?
test_uzf_unsteady.zip

martclanor Jun 27, 2024
Author

I am not sure about how to attach the UZF file, as the one that I have for this model is 2.7GB.

A bit tangent to the topic here but I was unable to implement UZF timeseries in this model without significantly increasing run times. This might be related to this issue: #1338, but I've been holding off on reopening the issue until I can double check this.

emorway-usgs · 2024-06-27T10:50:57Z

emorway-usgs
Jun 27, 2024
Collaborator

If, after making the previously suggested changes, you are still seeing such a large percent discrepancy in the UZF budget, it might be worth adding the PRINT_BUDGET keyword to the OPTIONS block and focusing attention on specific UZF objects with their own bad budgets. I've not encountered UZF-GWET showing up on the inflow side of the budget before.

4 replies

martclanor Jun 27, 2024
Author

Thanks for this suggestion. I assume here that you meant PRINT_FLOWS in the OPTIONS block of UZF? Using this setting, I have this output on the list file now (see complete extracted table here: uzf_summary_of_flows.csv).

 UZF PACKAGE - SUMMARY OF FLOWS FOR EACH CONTROL VOLUME   PERIOD      1   STEP        1
 ----------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                           PERCENT   
   NUMBER   CELLID                  INFLOW      OUTFLOW        GWF      INFILTRATION   REJ INF        UZET       STORAGE      IN - OUT    DIFFERENCE 
 ----------------------------------------------------------------------------------------------------------------------------------------------------
     1      (3,1)                 0.0000       0.0000      -55.052       55.052       0.0000       0.0000       0.0000       0.0000       0.0000     
     2      (3,2)                 0.0000       0.0000      -55.052       55.052       0.0000       0.0000       0.0000       0.0000       0.0000     
     3      (3,3)                 0.0000       0.0000      -49.132       49.132       0.0000       0.0000       0.0000       0.0000       0.0000     
     4      (3,4)                 0.0000       0.0000      -55.052       55.052       0.0000       0.0000       0.0000       0.0000       0.0000     
     5      (3,5)                 0.0000       0.0000      -49.132       49.132       0.0000       0.0000       0.0000       0.0000       0.0000     
     6      (3,6)                 0.0000       0.0000      -55.052       55.052       0.0000       0.0000       0.0000       0.0000       0.0000     
     7      (3,7)                 0.0000       0.0000      -57.419       57.419       0.0000       0.0000       0.0000       7.10543E-15  1.23746E-14
     8      (3,8)                 0.0000       0.0000      -55.052       55.052       0.0000       0.0000       0.0000       0.0000       0.0000     
     9      (3,9)                 0.0000       0.0000      -52.684       52.684       0.0000       0.0000       0.0000      -7.10543E-15 -1.34869E-14
     10     (3,10)                0.0000       0.0000      -52.684       52.684       0.0000       0.0000       0.0000      -7.10543E-15 -1.34869E-14
     11     (3,11)                0.0000       0.0000      -52.684       52.684       0.0000       0.0000       0.0000      -7.10543E-15 -1.34869E-14
     12     (3,12)                0.0000       0.0000      -55.052       55.052       0.0000       0.0000       0.0000       0.0000       0.0000     
     13     (3,13)                0.0000       0.0000      -17.759       17.759       0.0000       0.0000       0.0000       0.0000       0.0000     
     14     (3,14)                0.0000       0.0000      -52.684       52.684       0.0000       0.0000       0.0000      -7.10543E-15 -1.34869E-14
     15     (3,15)                0.0000       0.0000      -55.052       55.052       0.0000       0.0000       0.0000       0.0000       0.0000     
     16     (1,16)                0.0000       0.0000      -55.052       0.0000       0.0000       0.0000       0.0000      -55.052      -200.00     
     17     (3,16)                0.0000       0.0000       0.0000       0.0000       0.0000       0.0000       0.0000       0.0000       0.0000

Please note that this output is not anymore exactly the same model as in the original question (I apparently posted an old version, apologies) but the same problem persists.

Tried looking around and here are some notes from the attached csv:

In 63% of the cells, GWF = -1*INFILTRATION
In 94% of the cells with REJ-INF, INFILTRATION = -1*REJ-INF
INFLOW, OUTFLOW, UZET and STORAGE columns are just zero for all cells
The PERCENT DIFFERENCE column gives -200 whenever there's a significant difference in IN-OUT column
For some cells e.g. 3789, 4818, etc., GWF = -59.195 then all the other water balance terms are equal to zero
-1*min(GWF) = max(INFILTRATION) = -1*min(REJ INF) = -1*min(IN-OUT) = 59.195

Any of these perhaps point to the issue?

emorway-usgs Jun 28, 2024
Collaborator

Perhaps attach a copy of the UZF input file that includes everything through the first stress period and delete the rest. It seems all of your specified infiltration is passing through the UZF object and going straight to recharge. With regard to the cell that has a 200% discrepancy, that water may be draining from the UZF object which would mean that there should be some inflow from storage. Perhaps double check that the storage related parameters are as you intended.

martclanor Jun 28, 2024
Author

Here is a copy of the related UZF file: no_newt_40.zip

Here are the storage-related parameters that were used:

# Block: PACKAGEDATA
thtr = 0.03  # residual wc
thts = 0.4  # saturated wc
thti = 0.15  # initial wc

# Block: PERIOD
extwc = 0.03  # ET extinction wc

martclanor Jun 28, 2024
Author

I will follow this up with the truncated UZF input file and list file for an unsteady model run (with Newton) as soon as it finishes.

martclanor · 2024-06-28T13:15:36Z

martclanor
Jun 28, 2024
Author

An update on this which might be interesting:

I did two model runs where the only difference is that one is square_gwet = True while the other is linear_gwet =True

SQUARE GWET

list and uzf files: no_newt_40.zip

volume budget

UZF BUDGET FOR ENTIRE MODEL AT END OF TIME STEP 1, STRESS PERIOD 1

 CUMULATIVE UZF      L**3       RATES FOR THIS TIME STEP      L**3/T
 ------------------                 ------------------------

       IN:                                      IN:
       ---                                      ---
             GWF =           0.0000                   GWF =           0.0000
    INFILTRATION =   120391888.5863          INFILTRATION =      329840.7906
         REJ-INF =           0.0000               REJ-INF =           0.0000
            UZET =           0.0000                  UZET =           0.0000
         STORAGE =           0.0000               STORAGE =           0.0000

        TOTAL IN =   120391888.5863              TOTAL IN =      329840.7906

      OUT:                                     OUT:
      ----                                     ----
             GWF =   163094101.8070                   GWF =      446833.1556
    INFILTRATION =           0.0000          INFILTRATION =           0.0000
         REJ-INF =     8502607.5959               REJ-INF =       23294.8153
            UZET =           0.0000                  UZET =           0.0000
         STORAGE =           0.0000               STORAGE =           0.0000

       TOTAL OUT =   171596709.4029             TOTAL OUT =      470127.9710

        IN - OUT =   -51204820.8165              IN - OUT =     -140287.1803

PERCENT DISCREPANCY = -35.07 PERCENT DISCREPANCY = -35.07

VOLUME BUDGET FOR ENTIRE MODEL AT END OF TIME STEP 1, STRESS PERIOD 1

 CUMULATIVE VOLUME      L**3       RATES FOR THIS TIME STEP      L**3/T          PACKAGE NAME    
 ------------------                 ------------------------                     ----------------

       IN:                                      IN:
       ---                                      ---
          STO-SS =           0.0000                STO-SS =           0.0000     STORAGE                          
          STO-SY =           0.0000                STO-SY =           0.0000     STORAGE                          
             WEL =           0.0000                   WEL =           0.0000     WEL_KLEINE_ONT                   
             WEL =           0.0000                   WEL =           0.0000     WEL_GROTE_ONT                    
             WEL =           0.0000                   WEL =           0.0000     WEL_DWATER_ONT                   
             DRN =           0.0000                   DRN =           0.0000     DRN                              
             DRN =           0.0000                   DRN =           0.0000     DRN_LANDBOUW                     
             DRN =           0.0000                   DRN =           0.0000     DRN_MAAIVELD                     
             RIV =     4620917.0808                   RIV =       12660.0468     RIV_VL                           
             RIV =     2555036.7746                   RIV =        7000.1008     RIV_NL                           
             CHD =     2798712.3479                   CHD =        7667.7051     CHD                              
             LAK =           0.0000                   LAK =           0.0000     LAK                              
       UZF-GWRCH =   163094101.8070             UZF-GWRCH =      446833.1556     UZF                              
        UZF-GWET =   231379426.4097              UZF-GWET =      633916.2367     UZF                              

        TOTAL IN =   404448194.4201              TOTAL IN =     1108077.2450

      OUT:                                     OUT:
      ----                                     ----
          STO-SS =           0.0000                STO-SS =           0.0000     STORAGE                          
          STO-SY =           0.0000                STO-SY =           0.0000     STORAGE                          
             WEL =      549432.8184                   WEL =        1505.2954     WEL_KLEINE_ONT                   
             WEL =     8619200.0000                   WEL =       23614.2466     WEL_GROTE_ONT                    
             WEL =    14852834.5884                   WEL =       40692.6975     WEL_DWATER_ONT                   
             DRN =    62394251.3754                   DRN =      170943.1545     DRN                              
             DRN =   220314376.2229                   DRN =      603601.0307     DRN_LANDBOUW                     
             DRN =    24096106.5894                   DRN =       66016.7304     DRN_MAAIVELD                     
             RIV =     9823336.0190                   RIV =       26913.2494     RIV_VL                           
             RIV =     5350439.6440                   RIV =       14658.7388     RIV_NL                           
             CHD =     8095284.6808                   CHD =       22178.8621     CHD                              
             LAK =           0.0000                   LAK =           0.0000     LAK                              
       UZF-GWRCH =           0.0000             UZF-GWRCH =           0.0000     UZF                              
        UZF-GWET =           0.0000              UZF-GWET =           0.0000     UZF                              

       TOTAL OUT =   354095261.9384             TOTAL OUT =      970124.0053

        IN - OUT =    50352932.4816              IN - OUT =      137953.2397

PERCENT DISCREPANCY = 13.28 PERCENT DISCREPANCY = 13.28

LINEAR GWET

list and uzf files: no_newt_40_line.zip

volume budget

UZF BUDGET FOR ENTIRE MODEL AT END OF TIME STEP 1, STRESS PERIOD 1

 CUMULATIVE UZF      L**3       RATES FOR THIS TIME STEP      L**3/T
 ------------------                 ------------------------

       IN:                                      IN:
       ---                                      ---
             GWF =           0.0000                   GWF =           0.0000
    INFILTRATION =    32537901.8021          INFILTRATION =       89144.9364
         REJ-INF =           0.0000               REJ-INF =           0.0000
            UZET =           0.0000                  UZET =           0.0000
         STORAGE =           0.0000               STORAGE =           0.0000

        TOTAL IN =    32537901.8021              TOTAL IN =       89144.9364

      OUT:                                     OUT:
      ----                                     ----
             GWF =   171328553.0737                   GWF =      469393.2961
    INFILTRATION =           0.0000          INFILTRATION =           0.0000
         REJ-INF =      268156.3291               REJ-INF =         734.6749
            UZET =           0.0000                  UZET =           0.0000
         STORAGE =           0.0000               STORAGE =           0.0000

       TOTAL OUT =   171596709.4029             TOTAL OUT =      470127.9710

        IN - OUT =  -139058807.6007              IN - OUT =     -380983.0345

PERCENT DISCREPANCY = -136.24 PERCENT DISCREPANCY = -136.24

VOLUME BUDGET FOR ENTIRE MODEL AT END OF TIME STEP 1, STRESS PERIOD 1

 CUMULATIVE VOLUME      L**3       RATES FOR THIS TIME STEP      L**3/T          PACKAGE NAME    
 ------------------                 ------------------------                     ----------------

       IN:                                      IN:
       ---                                      ---
          STO-SS =           0.0000                STO-SS =           0.0000     STORAGE                          
          STO-SY =           0.0000                STO-SY =           0.0000     STORAGE                          
             WEL =           0.0000                   WEL =           0.0000     WEL_KLEINE_ONT                   
             WEL =           0.0000                   WEL =           0.0000     WEL_GROTE_ONT                    
             WEL =           0.0000                   WEL =           0.0000     WEL_DWATER_ONT                   
             DRN =           0.0000                   DRN =           0.0000     DRN                              
             DRN =           0.0000                   DRN =           0.0000     DRN_LANDBOUW                     
             DRN =           0.0000                   DRN =           0.0000     DRN_MAAIVELD                     
             RIV =    10758795.5766                   RIV =       29476.1523     RIV_VL                           
             RIV =     3619505.7313                   RIV =        9916.4541     RIV_NL                           
             CHD =    24118336.4562                   CHD =       66077.6341     CHD                              
             LAK =           0.0000                   LAK =           0.0000     LAK                              
       UZF-GWRCH =   171328553.0737             UZF-GWRCH =      469393.2961     UZF                              
        UZF-GWET =           0.0000              UZF-GWET =           0.0000     UZF                              

        TOTAL IN =   209825190.8379              TOTAL IN =      574863.5365

      OUT:                                     OUT:
      ----                                     ----
          STO-SS =           0.0000                STO-SS =           0.0000     STORAGE                          
          STO-SY =           0.0000                STO-SY =           0.0000     STORAGE                          
             WEL =      549432.8184                   WEL =        1505.2954     WEL_KLEINE_ONT                   
             WEL =     8619200.0000                   WEL =       23614.2466     WEL_GROTE_ONT                    
             WEL =    14852834.5884                   WEL =       40692.6975     WEL_DWATER_ONT                   
             DRN =     5999465.1658                   DRN =       16436.8909     DRN                              
             DRN =    17731795.9743                   DRN =       48580.2629     DRN_LANDBOUW                     
             DRN =     1067026.5840                   DRN =        2923.3605     DRN_MAAIVELD                     
             RIV =     1882142.6920                   RIV =        5156.5553     RIV_VL                           
             RIV =     1078157.6846                   RIV =        2953.8567     RIV_NL                           
             CHD =      382100.6870                   CHD =        1046.8512     CHD                              
             LAK =           0.0000                   LAK =           0.0000     LAK                              
       UZF-GWRCH =           0.0000             UZF-GWRCH =           0.0000     UZF                              
        UZF-GWET =    19171286.2806              UZF-GWET =       52524.0720     UZF                              

       TOTAL OUT =    71333442.4752             TOTAL OUT =      195434.0890

        IN - OUT =   138491748.3627              IN - OUT =      379429.4476

PERCENT DISCREPANCY = 98.52 PERCENT DISCREPANCY = 98.52

With the LINEAR GWET, UZF-GWET now becomes an outflow term, but PERCENT DISCREPANCY is increased. Tbh, I'm not sure if this is a step in the right direction, but perhaps this gives a hint about the root cause?

12 replies

martclanor Jul 2, 2024
Author

Thank you for these insights! Will work further with these in mind.

Meanwhile, another update:

I just noticed that SPD data in the model (including finf and pet) are being assigned to all UZF cells. Perhaps, adapting this to apply only to top UZF cells might do something especially for PET because based on the docs for UZF-perioddata-pet:

If IVERTCON is greater than zero then residual potential evapotranspiration not satisfied in the UZF cell is applied to the underlying UZF and GWF cells.

emorway-usgs Jul 3, 2024
Collaborator

I just noticed that SPD data in the model (including finf and pet) are being assigned to all UZF cells. Perhaps, adapting this to apply only to top UZF cells might do something especially for PET because based on the docs for UZF-perioddata-pet:

Just to be clear, are you seeing FINF values being applied to cells that have a landflag value equal to 1 and also to underlying cells? Remember that in a steady state stress period the applied FINF rates will pass through each dry cell in a vertical stack of cells. In the budget it will look like FINF is being applied to underlying cell, though it is just the steady state drainage from the overlying cell that happens to be equal to FINF in steady state stress period.

If IVERTCON is greater than zero then residual potential evapotranspiration (pET) not satisfied in the UZF cell is applied to the underlying UZF and GWF cells.

If, in a vertical stack of UZF objects, the water table is in a lower layer that is within the specified EXTDP and not all of the pET is satisfied with UZET from the overlying cell(s) and the cell hosting the water table, then the residual pET may still be satisfied with ET from the water table (GWET).

martclanor Jul 3, 2024
Author

Just to be clear, are you seeing FINF values being applied to cells that have a landflag value equal to 1 and also to underlying cells?

Short answer: no. FINF values are indeed only being applied to UZF cells with landflag = 1

Just did an experiment with two unsteady-state models:

MODEL 1: perioddata (with finf and pet ) is assigned to all UZF cells
MODEL 2: perioddata (with finf and pet) is assigned only to UZF cells which have landflag = 1 in the packagedata

Results are not exactly the same, but just slightly different, and I don't see which is better. This path is maybe a dead-end but just a question about this, do I have to apply the perioddata for all UZF cells?

Just in case the answer to the previous question is yes, how do I determine the extinction depth, extdp for the underlying UZF cells? Do I use the same value as their corresponding overlying cells? Or do I have to offset this with the thickness of the overlying cell?

So in this case, should it be:

UZF cell 1: extdp 1
UZF cell 2: extdp 1
UZF cell 3: extdp 1

or

UZF cell 1: extdp 1
UZF cell 2: extdp 1 - t1
UZF cell 3: extdp 1 - t1 - t2

Maybe another possible clue: I found some cells whose head is lower than the cell's bottom. Is this probably related to the reversed direction of GWET? Note that this is for an unsteady-model with Newton.

Also is it worth going for the linear_gwet implementation instead of the square_gwet? Model version with linear_gwet results into UZF-GWET being in the outflow side (instead of inflow) although it still has some issues with convergence on some stress periods.

emorway-usgs Jul 3, 2024
Collaborator

Results are not exactly the same, but just slightly different, and I don't see which is better. This path is maybe a dead-end but just a question about this, do I have to apply the perioddata for all UZF cells?

Only apply finf and pET to the cells with landflag=1. Specified boundary values like finf and pET are repeatedly used in successive stress periods if no overriding value is specified for the next stress period. So for example, if the specified pET is 0.01 in stress period 1 and you need it to be 0.0 in stress period two, you will need to explicitly set that for the appropriate cells (or use an empty PERIODDATA block to set all values equal to 0.0).

...how do I determine the extinction depth, extdp for the underlying UZF cells?

You do not need to worry about this. The EXTDP is applied starting from the cell with landflag=1. For example, in a stack of UZF objects that are each 2 units thick, if you specify EXTDP to be 3 units, then the code will internally sort out whether the water table is intersected by the extinction depth.

...I found some cells whose head is lower than the cell's bottom. Is this probably related to the reversed direction of GWET?

No, if the head is below the cell bottom then the UZF package should be taking care of the various budget terms. If you are able to recreate the budget issue with a small reproducible example I can run on my side, that will be the quickest way to get to the bottom of what might be going on.

...Also is it worth going for the linear_gwet implementation instead of the square_gwet.

Sorry but I cannot advise on how you should be modeling your particular setup. However, if you are able to recreate the problem using a small example problem where the budget looks good with linear_gwet but does not with square_gwet, I'm keenly interested in running that model locally.

martclanor Jul 4, 2024
Author

Attached here is a downscaled version of the model with the same budget issue.
us_dummy_ic_s.zip

Please let me know if this is workable enough or if I have to scale it down even more. Some notes about the model:

It was challenging to have it converging, so I tried just using a more lenient outer_dvclose and this one is set to outer_dvclose = 0.7. Hope that's fine.
The initial conditions used are based on the results of a steady-state run with the same model configuration.
The model is unsteady with 4 spd, 1 ts each.
It runs under 20-secs on my machine with mf 6.5.0.
The resulting UZF-GWET term for all 4 spds are in the inflow side
I can also confirm that upon switching from square_gwet to linear_gwet, the UZF-GWET term is moved to the outflow side.

Thanks a lot in advance!

langevin-usgs · 2024-06-28T13:18:53Z

langevin-usgs
Jun 28, 2024
Maintainer

Hey @martclanor, you mention that you are seeing this behavior for both steady state and transient simulations. UZF behaves very differently for these two cases. For steady state simulations, UZF does not track waves and instead does a simple calculation as described in the UZF1 Documentation, shown in italics below.

Steady state can be specified for the initial stress period of a simulation when using the UZF1 Package. When steady state is specified for the initial stress period, the ground-water recharge rate computed in UZF1 is set equal to the infiltration rate and ET is not removed from the unsaturated zone. The water content is constant within each model cell during steady state. The specified ET rate is subtracted from the infiltration rate to calculate a steady-state recharge rate. ET can also occur from ground water when the water table is above the ET extinction depth. A uniform water content profile is computed for each active cell, which is used automatically as the initial conditions for a following transient stress period.

Steady-state water content profiles may be printed to a file for specified locations. Initial water content values are not required when the initial stress period is specified as steady state. Thus, initial water-content values must not be specified within the UZF1 input file when the first stress period is steady state. Another option for developing initial water content profiles is to run the model for several years while repeating a cycle of infiltration rates. This step may be carried out subsequent to a steady-state simulation.

I assume the budget table for each uzf reach shown above is for a steady state simulation. If so, this is why the infiltration exactly equals the GWF term (which is recharge to the water table) and why storage is zero. I would expect this to look differently for a transient run.

Sorry if I've misunderstood your situation.

By the way, @emorway-usgs is the probably the best person to help with this. I see he's been responding, but he is also on vacation, so we should keep that in mind.

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UZF-GWET term on volume budget #1904

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UZF BUDGET FOR ENTIRE MODEL AT END OF TIME STEP 1, STRESS PERIOD 1

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UZF BUDGET FOR ENTIRE MODEL AT END OF TIME STEP 1, STRESS PERIOD 1

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UZF-GWET term on volume budget #1904

martclanor Jun 26, 2024

Replies: 4 comments · 18 replies

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SQUARE GWET

UZF BUDGET FOR ENTIRE MODEL AT END OF TIME STEP 1, STRESS PERIOD 1

VOLUME BUDGET FOR ENTIRE MODEL AT END OF TIME STEP 1, STRESS PERIOD 1

LINEAR GWET

UZF BUDGET FOR ENTIRE MODEL AT END OF TIME STEP 1, STRESS PERIOD 1

VOLUME BUDGET FOR ENTIRE MODEL AT END OF TIME STEP 1, STRESS PERIOD 1

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