Possible SWAT+ Check issue with monthly recall point-source flow summary
Namraj Jaishi
Hello SWAT+ Editor/SWAT+ team,
I am modeling the Caney Creek watershed in Montgomery County, Texas using SWAT+ rev. 61.0.2.61 and SWAT+ Editor v3.2.1. I added monthly recall point-source data using rec_typ = 2, with each pt###.rec file containing monthly flo values in m³, following the SWAT+ recall documentation.
I noticed a possible issue or confusing behavior in SWAT+ Check under the Point Sources section. SWAT+ Check reports:
Total Point Source + Inlet Load:
Flow = 8.54 cms
Sediment = 60,470 Mg/yr
Nitrogen = 824,017 kg/yr
Phosphorus = 865 kg/yr
Load from Inlet + PS:
Flow = 99.75%
However, when I directly audit the active monthly recall files listed in recall.rec, the point-source flow is much smaller:
Active sources:
pt017, pt026, pt032, pt043, pt055, pt077, pt087, pt097, pt103, pt107
Direct calculation from the active pt*.rec files:
Total flow over full simulation = 23,533,901.5 m³
Correct mean point-source flow = 0.02869 cms
Correct mean point-source flow = 0.6549 MGD
Correct maximum monthly point-source flow = 0.4324 cms
Correct maximum monthly point-source flow = 9.8701 MGD
The channel output also shows that streamflow is much larger than the point-source input. For example, in channel_sd_yr.txt, flo_out for the main channel is around 7–8 cms on average, so the point-source flow should not be close to 99.75% of total flow.
Interestingly, if I divide the total multi-year recall volume by about 32 days, I get almost the same value as SWAT+ Check:
23,533,901.5 m³ / (32 × 86,400 s) ≈ 8.51 cms
This is very close to the 8.54 cms shown in SWAT+ Check. It looks like SWAT+ Check may be converting the total simulation monthly recall volume using an incorrect or unintended time denominator, rather than calculating the average point-source discharge over the full simulation period.
Could you please clarify how SWAT+ Check calculates “Total Point Source + Inlet Load” for monthly recall objects? Is this expected behavior, or could it be a bug in the point-source flow summary for rec_typ = 2 monthly recall data?
For reference:
SWAT+ rev: 61.0.2.61
SWAT+ Editor: v3.2.1
Recall type: monthly, rec_typ = 2
flo units in pt*.rec: m³ per monthly timestep
Output folder: TxtInOut
Main files checked: recall.rec, pt*.rec, channel_sd_yr.txt, channel_sd_mon.txt
Thank you for your help.
gebregiyorgis Kassie
--
You received this message because you are subscribed to the Google Groups "SWAT+ Editor" group.
To unsubscribe from this group and stop receiving emails from it, send an email to swatplus-edit...@googlegroups.com.
To view this discussion visit https://groups.google.com/d/msgid/swatplus-editor/3f4da489-7096-487d-b2cb-9c754b36de26n%40googlegroups.com.
