Envision

The Willamette Water 2100 project is creating a computer model of the Willamette water system using Envision, a modeling platform developed at OSU. Envision integrates these software subsystems:

  • a geographic information system that manages data through space and time,
  • a standard interface for "plugging in" hydrological, ecological, and economic process models,
  • explicit rules representing the many societal institutional mechanisms that create opportunities and impose constraints on private actions. These include rules such as those implemented by reservoir management, and changing technologies and land use regulations, and
  • a system for compiling and summarizing model output and for visualizing the results of alternative water and land scenarios.

The Envision platform enables disciplinary models to communicate via a landscape, a shared data repository that represents instantaneous conditions at specific locations. From a system perspective, each time a model runs, it draws as its input, the outputs from other state-of-the-art models (plug-ins) running within the framework. Envision synchronizes models as they step through time on their own time scales. For example, it runs a hydrological model with a daily time step 30 times before running an economic model with a monthly time step. Although the economic model might represent hydrological events in a cursory manner, it takes advantage of the calculations that the state-of-the-art hydrological model made during the previous time interval. Envision thereby enables each disciplinary model to gain in predictive power.

The WW2100 model of the human system is characterized by a set of economic models and institutional constraints. The main economic models include models of private land markets and land use change, urban water use and agricultural water use. Individuals such as agricultural producers and urban dwellers make choices reflecting economic models of demand and supply for land and water.  Institutions play a key role in these economic choices, by imposing constraints, creating opportunities, and altering incentives. These “institutions” come in the form of laws, regulations and management of public infrastructure, including minimum instream flows.

The WW2100 model described in the figure below achieves unprecedented integration of a range of state-of-the-art hydrological, ecological, and economic models, and it can incorporate changes in public policy and resource management into a decision-making framework.

Diagram of the Willamette Water 2100 modeling framework.

The Envision website provides greater detail about the general platform framework and how, in other contexts, it has been integrated with a multi-agent-based approach to modeling the human system for scenario-based community and regional planning assessments.