Updates on IWFM Features CWEMF Annual Meeting Folsom

Updates on IWFM Features CWEMF Annual Meeting Folsom, California April 22 – 24, 2019 Emin Can Dogrul California Department of Water Resources

Outline l Model feature tagging l Multi-model simulations l IWFM Application Programming Interface (API) l Upcoming developments l Announcements

Model Feature Tagging l Issue: • IWFM model features (nodes, elements, stream nodes, stream reaches, etc. ) needed to be numbered sequentially, starting from 1 • Difficult and error-prone to modify grid, add stream nodes/reaches, etc. after a model is built l Solution: • Model feature tagging: Removed requirement of numbering model features sequentially, starting from 1; i. e. feature numbers are tags, not indices l Benefits: • Allows easy grid modification, local grid refinement, addition/deletion of stream nodes/reaches • Carving out child models from parent models (e. g. create a local model by carving it out from C 2 VSim-FG) • IWFM automatically identifies the stream network upstream-downstream orientation

Multi-Model Simulations: Overview l Initially requested by a user for a specific IWFM project l Ability to run multiple (neighboring), independently developed IWFM models concurrently l Neighboring models can be linked together and iterated back-and-forth at each timestep until flow between the models converge l Uses Fortran coarrays

Multi-Model Simulations: Linkage points

Multi-Model Simulations: Linkage points l Groundwater flow in the horizontal • Grid alignment at model interfaces is not required • Multiple nodes in one model can be linked to a single node in another model

Multi-Model Simulations: Linkage points l Groundwater linkage in the horizontal • Grid alignment at model interfaces is not required • Multiple nodes in one model can be linked to a single node in another model l Groundwater linkage in the vertical • Stratigraphy alignment at model interfaces is not required • Multiple aquifer layers in one model can be linked to a single layer in another model • IWFM computes linkage conductances based on hydraulic conductivity, layer thickness, effective length along the boundary nodes and distance between the linked nodes A A

Multi-Model Simulations: Linkage points l Stream linkage • Stream flows from one model can flow into another model • Bypasses exported from one model can be imported into another model l Water supply linkage • Diversions from one model can be delivered to another model • Currently, these diversions cannot be adjusted automatically to meet demand in another model

Multi-Model Simulations: Linkage points l Other linkages (not yet implemented) • Pumping in one model delivered to another model • Rainfall runoff and agricultural/urban return flow generated in one model flowing into stream nodes of another model

Multi-Model Simulations: Benefits l Local models can be linked to a regional model (e. g. C 2 VSim) for dynamic boundary conditions l Models developed separately by neighboring GSAs can be linked to test the validity of and improve the boundary conditions l Planned future developments: • Linking IWFM to WRIMS (i. e. C 2 VSim linked to reservoir systems analysis) • Combined with multi-model simulation will allow linking detailed, local-level water management to Central-Valleywide management

Multi-Model Simulations: Limitations l Models must have the same simulation period l Models must have the same timesteps l Currently, up to 8 models can be run concurrently

Other Improvements: IWFM Application Programming Interface (API) l Public release of IWFM API l For tool developers: • Allows access to IWFM model features and results through their software • Eliminates the need to duplicate IWFM logic within their code • Eliminates the need to update their code when IWFM code is updated l Procedures callable from Python, C#. NET, VB. NET, Java and VBA

Upcoming Developments l Parallel processing using Open. MP * On a laptop with 8 processors l Linking WRIMS and IWFM (i. e. implement reservoir systems analysis in IWFM) l Use of WRESL code in groundwater optimization studies in conjunction with SGMA l Develop web application for C 2 VSim-FG

Announcements l IDC workshop – April 30 -May 1 in Davis, CA l IWFM workshop – June 4 -7 in Davis, CA

Questions?