GLEAMS Modeling Vision

 

Several issues drive the requirement for developing mathematical models to track movement of contaminants in the watershed environment including:

• To gain a better understanding of the fate and transport of chemicals by quantifying their reactions, speciation and movement (Schnoor[1]);
• To determine chemical exposure concentrations to aquatic organisms and/or humans in the past, present and future (Schnoor[2]);
• To predict future conditions under various loading scenarios or management action alternatives (Schnoor[3]); and

• To assess the risk to environment and human health from the chemical exposure.

 

In short, modeling is necessitated by a need to know what contaminants are in the environment, how they move about, how they impact man and the environment, and how they can be controlled or limited in the future. All of these factors motivate the GLEAMS modeling activity.

 

GLEAMS is actively engaged in development of a series of models for the assessment of contaminant transport and the risk to man and the environment.  These models cover a wide range from small-scale processes to the development of a complete end-to-end system within a GIS environment.  GLEAMS will initially assess is the fate and transport of PCB contamination through the Kalamazoo River watershed.

 

Past Limitations:

The GLEAMS activity builds upon and enhances past modeling efforts in this area.  Limitations of past modeling activities include the following:

• In the past, assessment modeling concentrated on hydrodynamic portion of the problem.
• The models did not include the entire cycle of hydro coupled with chemical and biological interactions.
• Hydrodynamic modeling was limited as:

–         Sediment and contaminant resuspension is not well modeled;

–         Recreational boating not considered;

–         Runoff is not adequately addressed – simple model used;

–         Chemistry is an issue;

–         Ground water contribution not considered;

–         No consideration of bioturbation;

–         Episodic events not considered; and

–         Interaction with larger bodies of water not assessed.

• Other considerations not included:

–         Effect of dams – turbulence in overflow, dam failure;

–         Understanding and modeling of the food chain; and

–         In situ absorption of contaminants not assessed.

 

GLEAMS Enhancements:

In addition to addressing the limitations above, the GLEAMS modeling activity will addresses the contaminant transport and impact in all cases found in the riverine environment:

• Bulk solids
• Sediment bound
• Colloidal bound
•  

A summary diagram of the system being developed can be seen here.  Unique aspects of the modeling activity include:

• Development of KALTOX, a new 1-d and 2-d PCB contaminant transport model through a partnership with the Ukrainian Center for Environmental and Water Projects (UCEWP);

• Development of a sediment/contaminant resuspension model to account for turbulence from boat activity in the lakes;
• Implementation of a new food web model for bioaccumulation;
• Development of a nested modeling system for assessment of river plume transport into Lake Michigan;
• Implementation of sub-models to assess flood plane inundation and flooding/erosion of impoundment areas;
• Development of a new low cost, user configurable, water quality buoy (Automatic Lagrangian Water Quality Assessment System – ALWAS) for the acquisition of standard river and lake water quality data;
• Implementation of the Water Quality Index for rapid assessment of water quality from the ALWAS buoy;
• Development and operation of new imagery processing algorithms for SeaWIFS and MODIS satellite imagery through a partnership with the Nansen International Environmental Remote Sensing Center (NIERSC) in St. Petersburg, RU.  The algorithms compute Chlorophyll A, Dissolved organic carbon, and suspended minerals in the surface waters;
• Extensive data assimilation activities to calibrate and update the modeling system.  The data incorporated is derived from the existing stream and meteorological stations; new MODIS and SeaWIFS satellite data; in situ observations collected from ALWAS buoy deployments; and other data collected in the seasonal field programs;
• Expansion of the modeling system to allow for easy assessment of other contaminants in additional geographic locations - system is scaleable and transportable; and
• Derivation of decision support products as meaningful output from the modeling activity.