Environmental Assessment Program

Modeling the Environment

A computer model is a representation of some part of the environment that helps us understand and predict potential changes. Weather forecasting, for example, relies on computer models.

At the Department of Ecology, we develop these mathematical tools to represent water systems, like a river or Puget Sound. They help us understand what factors contribute to problems in these waters and plan a course of action to manage the relevant factors.

Tools and Resources for Modeling

We use several tools developed by Ecology or by others. Each tool needs to be customized for a certain body of water. Many of these tools are used to identify sources of pollution in water quality improvement plans, or Total Maximum Daily Load (TMDL) studies. Several of our tools are used all over the world.

Models for Total Maximum Daily Load Studies links to many tools used in modeling TMDL water-cleanup plans. Descriptions and downloads are here.

Freshwater Modeling Projects

Several projects involve the use of computer models applied to freshwater quality.

SUSTAIN Modeling for Controlling Toxic Chemicals in Small Streams describes an evaluation of a tool to model toxics reductions with stormwater management in small streams.

Puget Sound Modeling Projects

Computer models applied to Puget Sound help us to understand if a water-cleanup plan is needed. These tools allow us to predict what Puget Sound might look like without the effects of different factors.

Focus on: Water Quality Modeling in Puget Sound is a two-page publication that describes the models being used in Puget Sound.

Puget Sound/Salish Sea Model describes a study of dissolved oxygen levels in Puget Sound and the Salish Sea

South Puget Sound Dissolved Oxygen Study describes a computer-modeling effort undertaken to address low levels of dissolved oxygen in the southern part of Puget Sound.

South Puget Sound Dissolved Oxygen Study Publications is a page that offers additional detailed information on this large-scale study. 

Puget Sound Models describes how water-quality models work in Puget Sound and why we need more than one type of model to diagnose problems in the Sound.

Puget Sound Dissolved Oxygen Modeling Study: Development of an Intermediate Scale Water Quality Model is an Ecology publication contracted through the Pacific Northwest National Laboratory that describes the development of a coupled hydrodynamic and water quality model for Puget Sound.

Quality Assurance Project Plan: Puget Sound Dissolved Oxygen Modeling Study: Intermediate-scale Model Development is the plan for the development of an integrated model for studying dissolved oxygen in the sound.

South Puget Sound Dissolved Oxygen Study: Using Models to Inform Management Decisions is a scientific poster describing the modeling approach in the southern Puget Sound.

Other Reports and Publications

Using Models to Compare and Prioritize Actions in Puget Sound: Who’s Modeling What and Why? is a scientific poster presented at the Puget Sound Georgia Basin Ecosystem Conference in June 2009.

Simulation of annual biogeochemical cycles of nutrient balance, phytoplankton bloom(s), and DO in Puget Sound using an unstructured grid model is an article from the journal Ocean Dynamics (2012) co-published with the Department of Ecology.

Calibration of a three-dimensional model of water quality in South Puget Sound is a scientific poster presented at the 2011 Salish Sea Conference in British Columbia, Canada that describes model calibration.

Tidally averaged circulation in Puget Sound sub-basins: Comparison of historical data, analytical model, and numerical model is an article from the journal Estuarine, Coastal and Shelf Science from July 2011, co-published by the Department of Ecology.

Seasonal Variations in Flushing Time for Quartermaster Harbor, an Enclosed Puget Sound Estuary is a scientific poster presented at the Salish Sea Ecosystem Conference in October 2011.