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SCHISM

Semi-implicit Cross-scale Hydroscience Integrated System Model

Dr. Joseph Zheng with the Center for Coastal Resources Management at the Batten School & VIMS views a SCHISM simulation on his computer that shows different colors on a map of the Chesapeake Bay..

SCHISM is an open-source, community-supported modeling system developed at VIMS and designed for seamless simulation of 3D water circulation across scales—from creeks and rivers to estuaries, continental shelves, and the open ocean. Built on flexible unstructured grids, SCHISM allows researchers and resource managers to focus computational power where it matters most while maintaining efficiency across vast model domains.

What SCHISM Does

SCHISM solves the fundamental equations governing water motion to simulate how water moves through complex coastal environments. Its applications span a wide range of pressing coastal challenges, including storm-surge and flood prediction, water quality assessment, sediment transport, oil spill tracking, coastal ecology, and wave-current interaction.

The model’s cross-scale design means a single SCHISM simulation can capture processes occurring at very different spatial scales—for example, tracking how ocean conditions influence circulation patterns within a small tidal creek—without requiring separate models stitched together.

A Comprehensive Modeling System

SCHISM is more than a hydrodynamic model. It integrates a suite of coupled modules that address interconnected physical, chemical, and biological processes:

  • Wave modeling (WWM-III) for simulating wind-driven waves and their interaction with currents
  • Sediment transport (CSTM; SED2D) for tracking the movement of sediments through waterways
  • Water quality (CE-QUAL-ICM) for modeling nutrient cycling, dissolved oxygen, and other indicators of ecosystem health
  • Ecology and biology (CoSINE; EcoSim2.0) for simulating plankton dynamics and food-web processes
  • Tidal Marsh Model (TMM) for understanding marsh evolution in response to sea-level rise, a module developed by CCRM at VIMS

Next-Generation Bay Model

In 2022, the U.S. Environmental Protection Agency’s Chesapeake Bay Program selected SCHISM as its next-generation estuary model to guide Bay restoration. SCHISM’s finer resolution and capacity to integrate across water and land will support more localized management decisions as regulators work to meet increasingly stringent water quality standards across the watershed.

As sea level rises and the Bay’s shoreline shifts landward, SCHISM’s detailed representation of the coast enables coupling with watershed and atmospheric models to deliver more accurate, localized predictions of climate-change impacts.

Global Reach, Local Roots

Developed by Dr. Joseph Zhang of VIMS’ Center for Coastal Resources Management and a worldwide community of contributors, SCHISM has been applied to regional seas, bays, and estuaries around the globe. Applications include operational forecast systems in the Chesapeake Bay, San Francisco Bay-Delta, the North and Baltic Seas, and coastal waters of Taiwan, among many others.

SCHISM is licensed under Apache 2.0 and its source code, documentation, and user manual are freely available.

Resources

How to Cite SCHISM

Zhang, Y., Ye, F., Stanev, E.V., Grashorn, S. (2016). Seamless cross-scale modeling with SCHISM. Ocean Modelling, 102, 64–81.

Zhang, Y. and Baptista, A.M. (2008). SELFE: A semi-implicit Eulerian-Lagrangian finite-element model for cross-scale ocean circulation. Ocean Modelling, 21(3-4), 71–96.