cwatm_dynamic module

class cwatm.cwatm_dynamic.CWATModel_dyn

Bases: cwatm.management_modules.dynamicModel.DynamicModel

CWatM dynamic model execution class for temporal hydrological simulation.

This class implements the temporal loop of the CWatM hydrological model, executing all hydrological processes for each time step in the simulation period. It coordinates the sequential execution of hydrological modules to simulate the complete water cycle including precipitation, evapotranspiration, soil processes, groundwater, surface runoff, routing, and water management.

The dynamic execution follows a specific sequence to maintain physical consistency and proper water balance accounting throughout the hydrological system.

Global variables

Variable [self.var]	Type	Description	Unit
channelStorage	Array	Channel water storage	m3
unmetDemand_runningSum	Array	Unmet water demand (too less water availability)	m
totalET_WB	Array	Total evapotranspiration including waterbodies	m
lakeReservoirStorage	Array	Storage of lakes and reservoirs	m3
tws	Array	Total water storage	m
modflow	Flag	True if modflow_coupling = True in settings file	bool
storGroundwater	Array	Groundwater storage (non-fossil). This is primarily used when not usin	m
smallevapWaterBody	Array	Evaporation from small lakes	m
EvapWaterBodyM	Array	Evaporation from lakes and reservoirs	m
dynamicLandcover	Flag	If landcover changes per year or is constant	bool
totalET	Array	Total evapotranspiration for each cell including all landcover types	m
totalSto	Array	Total soil,snow and vegetation storage for each cell including all lan	m
InvCellArea	Array	Inverse of cell area of each simulated mesh	1/m2
EvapoChannel	Array	Channel evaporation	m3
gridcell_storage	Array	storage of water due to runoff concentration	m
groundwater_storage_available	Array	Groundwater storage. Used with MODFLOW.	m
lakeResStorage	Array		–
smalllakeStorage	Array		–
unmetDemand	Array	Unmet groundwater demand to determine potential fossil groundwaterwate	m

Variables

• attributes are inherited from the parent DynamicModel class and (All) –

• in the CWATModel_ini class, including (initialized) –

• Hydrological module instances (-) –

• Model state variables (self.var) (-) –

• Configuration parameters (self.conf) (-) –

• Timing and output systems (-) –

Notes

The execution order is critical for maintaining water balance and physical consistency. The sequence follows the natural hydrological cycle from atmospheric inputs through terrestrial processes to surface water routing and water management.

Performance timing is tracked for each major process group to identify computational bottlenecks and optimize model efficiency.

dynamic()

Execute one time step of the complete hydrological simulation.

Performs the temporal execution of all hydrological processes for the current time step, following the natural sequence of the water cycle. This method coordinates all hydrological modules to simulate water movement and storage changes throughout the terrestrial hydrological system.

The execution sequence includes: 1. Time step management and meteorological data reading 2. Potential evapotranspiration calculation 3. Precipitation partitioning (rain/snow) and snow processes 4. Land cover dynamics and irrigation scheduling 5. Soil water processes across different land cover types 6. Groundwater processes (standard or MODFLOW coupling) 7. Surface runoff concentration and small water body processes 8. Channel routing and large water body management 9. Water quality calculations 10. Total water storage accounting 11. Environmental flow assessment 12. Output generation and state variable updates

Parameters

None – All required data accessed through self.var and module instances

Returns

Results stored in model state variables and written to output files

Return type

None

Notes

Special execution modes: - Environmental flow only: If calc_environflow is True and

calc_ef_afterRun is False, only environmental flow is calculated

• Calibration mode: If Flags[‘calib’] is True, only meteorological data reading and output generation are performed

Output verbosity controlled by flags: - ‘v’ or ‘veryquiet’: No progress output - ‘l’ or ‘loud’: Time step and discharge information - ‘t’ or ‘printtime’: Detailed timing of each process

Total Water Storage (TWS) calculation includes: - Groundwater storage (available or with unmet demand accounting) - Soil moisture storage across all layers and land cover types - Surface water storage (lakes, reservoirs, channels) - Runoff concentration storage (if enabled)

MODFLOW integration: - When self.var.modflow is True, uses groundwater_modflow_module - Requires proper finalization at simulation end to close files - Temporary MODFLOW files must be properly managed for multi-run scenarios

i = 1