Variables from STEMMUS_MODFLOW that needs to be included in STEMMUS_SCOPE for BMI purposes

[MostafaGomaa93]

Hi @yijianzeng and @Lianyu-Yu

Looking at Lianyu code (branch "STEMMUS_MODFLOW_v1.0.0."), in the main script file "MainLoop11.m", lines 85->87, there are the "hBOT" and "IBOT" variables. Those variables are already calculated in a separate function "TIME_INTERPOLATION.m", then they are passed to the main script "MainLoop11.m" and in the boundary condition calculations at the h_BC.m file.

However, those variables are not in STEMMUS_SCOPE source code. As I understand, we need to include these variables in the source code to let STEMMUS receive info from MODFLOW, right? Could you please explain what do "hBOT" and "IBOT" mean?

[MostafaGomaa93]

@Lianyu-Yu Could you please also explain the meaning of all variables of the "TIME_INTERPOLATION.m" function

T1, T0 ,IP ,BOT ,HPILLAR1N, HPILLAR0, T, DELT, X, NUMNP, Q3DF, ADAPTF

[MostafaGomaa93]

@Lianyu-Yu Could you aslo please explain what is the functionality of the Diff_moisture_heat.m file?

example, what is the use of hBOT in this line?

[Lianyu-Yu]

Hi @yijianzeng and @Lianyu-Yu

Looking at Lianyu code (branch "STEMMUS_MODFLOW_v1.0.0."), in the main script file "MainLoop11.m", lines 85->87, there are the "hBOT" and "IBOT" variables. Those variables are already calculated in a separate function "TIME_INTERPOLATION.m", then they are passed to the main script "MainLoop11.m" and in the boundary condition calculations at the h_BC.m file.

However, those variables are not in STEMMUS_SCOPE source code. As I understand, we need to include these variables in the source code to let STEMMUS receive info from MODFLOW, right? Could you please explain what do "hBOT" and "IBOT" mean?

"hBOT" is the water head at the bottom soil layer; "IBOT" is the layer index where the current "bottom“ is. please see line 26 of the hBC.m file for how "hBOT" and "IBOT" are used.

[Lianyu-Yu]

@Lianyu-Yu Could you please also explain the meaning of all variables of the "TIME_INTERPOLATION.m" function

T1, T0 ,IP ,BOT ,HPILLAR1N, HPILLAR0, T, DELT, X, NUMNP, Q3DF, ADAPTF

T1, is the end of the current time step; T0, is the start of the current time step; IP, indicate the number of STEMMUS columns for MODFLOW; BOT, is the elevation of the bottom layer of MODFLOW; HPILLAR1N, water heads at the end of the current time step; HPILLAR0, water heads at the start of the current time step; T, is the end of the current time step; DELT, is the time interval of the current time step; X, is the layer thickness of STEMMUS soil layers; NUMNP, is the total soil layers in STEMMUS; Q3DF, indicator for the quasi-3d simulation =1, yes; =0, no; ADAPTF, indicator for the adaptive lower boundary setting, =1, the moving lower boundary scheme is used; =0, the fixed lower boundary scheme is used.

[Lianyu-Yu]

@Lianyu-Yu Could you aslo please explain what is the functionality of the Diff_moisture_heat.m file?

example, what is the use of hBOT in this line?

Diff_moisture_heat.m is to run the Richards' equation and to obtain the updated soil matric potential "hh". hBOT, is the bottom water head, which is used to setup the bottom boundary condition of STEMMUS, please see Line 26 in h_BC.m for how it is used.

[MostafaGomaa93]

Hi @Lianyu-Yu

Could you please fill in the table with the meaning of the variables of the HYDRUS1RECHARGE

	Variable in MainLoop00.m	Variable in HYDRUS1RECHARGE	Description
Ouput	dMOD	-	Correction term for the recharging water flux
Ouput	QQS	-	Cumulative water flux out of the moving domain
Ouput	DW	-	Vadose zone water amount in the moving balance domain
Ouput	RRrN	RrNGG	the upper boundary water flux at the current timestep
Ouput	RrO	RrOGG	the upper boundary water flux at the old timestep
Ouput	ZTB1	ZTB1G	the soil layer thickness from the top soil surface to the phreatic surface at the end of time step
Input	T1	TEND1/86400	time at the end of the timestep, not in use
Input	T0	TTIME	time at the start of the time step
Input	ITERQ3D	ITERQ3D	indicator for the quasi-3d iteration simulation
Input	IP	IP0STm	Number of the MODFLOW subzones (STEMMUS soil columns)
Input	IGRID	IGRID	not in use
Input	Q3DF	Q3DF	indicator for the quasi-3d simulation
Input	THETA0	THETA0	soil water content at the start of the timestep
Input	ICTRL0	ICTRL0	the index of soil layer where the phreatic surface is, at the start of the time step
Input	THN	STheta_LL	soil water content at the end of the timestep
Input	T	TIME/86400	time step, not in use
Input	QS	QS	cumulative water flux out of the moving domain
Input	DT	Delt_t/86400	time step, not in use
Input	DELT	TTEND	time step
Input	ZTB0	ZTB0G	the soil layer thickness from the top soil surface to the phreatic surface at the start of time step
Input	HNEW	Shh	soil matric potential at the end of time step
Input	KPILLAR	KPILLAR	MODFLOW layer number corresponds to STEMMUS soil layers
Input	BOT	BOTm	elevation of MODFLOW bottom
Input	RrN	RrNG	the upper boundary water flux at the current timestep
Input	SY	SYSTG	specific yield
Input	SS	SSSTG	specific storage
Input	X	XElemnt	cumulative soil layer thickness
Input	KTN	KTN	number of MODFLOW timesteps

[MostafaGomaa93]

Hi @Lianyu-Yu

Could you please explain the difference between the outputs of the functions FINDTABLE and TIME_INTERPLATION? I am still confused about the difference between the two functions

Function	Varaiable	Meaning
TIME_INTERPOALTION	hBOT	head of the bottom layer where below that layer is the groundwater zone
TIME_INTERPOALTION	IBOT	index of the soil layer that includes the groundwater head
FINDTABLE	ZTB	soil layer thickness from the top of the soil to the phreatic surface
FINDTABLE	ICTRL	the index of soil layer where the phreatic surface is

[Lianyu-Yu]

Hi @MostafaGomaa93 The explanation of "HYDRUS1RECHARGE.m" corresponds to the Appendix A in the file: https://doi.org/10.5194/gmd-2022-221, or the methodology part in this file: https://doi.org/10.5194/hess-23-637-2019. Hope it is helpful to you.