Example of Case Studies ================================== Synthetic Test Cases ~~~~~~~~~~~~~~~~~~~~~ A total of 10 synthetic test cases have been developed to verify OpenWQ's outputs against analytical solutions. These tests cover batch reactors with different reaction orders and advection-dispersion transport scenarios. See :doc:`Synthetic tests ` for the full list. The JSON input files for each synthetic test can be obtained from: https://github.com/ue-hydro/synthetic_tests PHREEQC River Geochemistry ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ A test case demonstrating PHREEQC geochemical modeling coupled with mizuRoute river routing is available in the ``test_case_phreeqc/`` directory of the mizuRoute-OpenWQ repository. This example simulates the transport and geochemical evolution of Ca, Mg, and Na through a river network, including: * Equilibrium speciation of dissolved species * Advective transport between river reaches * Temperature-dependent reaction calculations * HDF5 output of species concentrations Configuration files include: * ``openWQ_master.json`` -- Master configuration with Forward Euler solver * ``openwq_in/openWQ_config.json`` -- Initial conditions (Ca, Mg, Na in mol/kgw) * ``openwq_in/openWQ_MODULE_PHREEQC.json`` -- PHREEQC module settings * ``openwq_in/openWQ_MODULE_TD.json`` -- Pure advection transport * ``openwq_in/phreeqc_river.pqi`` -- PHREEQC input file * ``openwq_in/phreeqc.dat`` -- Thermodynamic database Nutrient Cycling (BGC-Flex) ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ OpenWQ's flexible reaction network approach is well suited for nutrient cycling simulations. Using the BGC-Flex module, users can define nitrogen and phosphorus cycle reactions with temperature-dependent kinetics. Example applications include: * **Nitrogen cycle**: Nitrification, denitrification, mineralization, and plant uptake with temperature and moisture dependencies * **Phosphorus cycle**: Sorption-desorption, mineralization, and particulate transport * **Dissolved oxygen**: BOD decay, reaeration, and sediment oxygen demand These reaction networks are defined entirely in JSON configuration files. See :doc:`Modules <4_1_3Modules>` for the file format and the :doc:`Theoretical Foundation <2_1_Theoretical>` for the underlying equations.