An important component of an overall mutrients model for the northern river systems is the development of appropriate dissolved oxygen models. This study tries to assess the ability of the models (dissolved oxygen model DOSTOC) to predict observed conditions and to identify field research needs for model refinement.

Summarizes the major modelling projects undertaken to model water quality in the Peace, Athabasca, and Slave river systems. The first section describes the scope of the problem of modelling water quality in large complex systems that are relatively oligotrophic, located at relatively high altitudes, and experience highly seasonal environmental fluctuations. It also provides a summary of the models used to predict key water quality variables. Section 2 gives a general overview of the utility and shortcomings of water quality models, with the goal of establishing key criteria for assessing the successes of models developed by the Northern River Basins Study (NRBS). Section 3 summarizes key findings of the NRBS models and evaluates the results against criteria outlined in section 2. Section 4 presents a series of recommendations for modelling dissolved oxygen, transport and fate of contaminants, and distribution of contaminants in the food chain, along with strategic suggestions for future work.

The aim of this study was to examine the existing model approach and to make recommendations for improved modelling of under-ice dissolved oxygen (DO) concentrations in the Athabasca River. Previous modelling efforts have involved using the DO simulation model DOSTOC, but discrepancies between observed and predicted DO concentrations for 1992 and 1993 highlighted the needs for a review and assessment of the modelling approaches used. This report reviews the structure of the DOSTOC model and input data used for modelling, then describes a stochastic run of the model using the best available values for input data and process rates, including revised rates and ratios for converting five-day biological oxygen demand (BOD) values to ultimate BOD values, measured values for sediment oxygen demand and sedimentation, and a temperature correction for pulp mill BOD decay rates. Simulation results indicate whether the model could predict DO for 1990-94 winters. Regression equations were also developed relating DO concentration to river distance.

Describes and presents simulation results from numerical models of the transport and fate of environmental chemicals in northern Alberta rivers. The models were developed using the USEPA WASP modelling system and were structured as one-dimensional (longitudinal) models with separate, interacting water column and bed sediment compartments. Seven selected organic chemicals were simulated over 1992-93 for the Athabasca River and over 1990-91 for the Wapiti/Smoky River system. Chemicals simulated included 2,3,7,8-tetrachloro dibenzofuran, dehydroabietic acid, and phenanthrene. The models were first calibrated for sodium and total suspended solids. Organic chemicals were simulated using a set of environmental fate constants developed from a literature search, numerical estimation software, and estimation from field data. Results of initial simulations were compared to observed data and adjustments made to selected constants to improve the calibration.

The NTBS was designed to address the ecological concerns about pulp mill expansion, and to increase scientific knowledge about environmental conditions [ecology, ecosystem sustainability, water pollution and control, habitat, effect on fish and fishing, etc.] in the major river systems of the north. The study's objectives were to gather and interpret sound scientific information about the basins, develop appropriate recommendations for basin management, and communicate effectively with the public. The government response report confirms the governments' commitment to ecosystem sustainability and to pollution control in northern rivers. First Nations and Metis aboriginal [native] peoples contributed significantly to the NRBS.