A fast/automated watershed modeling workflow with the Penn State Integrated Hydrologic Model (PIHM): Essential data, simulation, applications and visualization

The Penn State Integrated Hydrologic Model (PIHM) is an multi-process, multi-scale, multi-time-step hydrologic model where the dominant hydrological processes are fully coupled using the semi-discrete Finite Volume Method. The hydrologic processes include land surface, groundwater and river, which are fully coupled and solved together. The high spatial and temporal resolution in PIHM provides detailed and reliable hydrologic metrics in a watershed.

The PIHM System consists of PIHM (the hydrologic model) and PIHMgis (a data processing tool kit). Thanks to the findings and experience from intensive hydrologic modeling in watersheds all over the world for the past 15 years, the PIHM group released a new PIHM System that includes PIHM++, an updated model fully rewritten in C++, and PIHMgisR, an R package to prepare, analysis and visualize the input/output of the model. The new PIHM system provides capabilities for public data downloads, pre-processing, hydrologic modeling, automatic calibration, post-processing and spatial visualization, and is fully open-source and ready for hydrological modelers to use. Both PIHM++ and PIHMgisR are available on GitHub.

Here we introduce the development philosophy of PIHM, from perceptual to computational structures of watershed hydrology. We select two watersheds (one in Africa and the other in California) as examples to demonstrate the workflow and capabilities of PIHM System. In modeling these examples, we exploit national/global public datasets and exemplify the workflow that includes data management, hydrologic analysis, model calibration and visualization capabilities. The modeling system not only supports fast deployment of hydrologic modeling functionality, but also benefits community modeling in applications of hydrology-related research fields, such as limnology, agriculture, climate change and Coupled-Natural-Human systems.