Scoping Proposal Linking Physical, Biological and Aqueous Geochemical Processes to Ecosystem Responses
This proposal is designed to evaluate the potential for developing a model that can answer the following question:
* In order to meet compliance standards, how do project operations affect the limnological processes in the reservoir and change the biological availability of contaminants, heavy metals, within the system?
This specific effort is intended to focus on Reclamation's need for an ecosystem approach to describe the linkage of project operations to the downstream and in reservoir environment. Modeling tools are effective in understanding and predicting system responses to altered operations: total maximum daily loads (TMDLs), climate change, remediation activities, and other anthropogenic influences. Therefore, this scoping proposal is intended to identify one modeling tool that can be enhanced to represent both the limnological processes associated with complying with water quality standards and be able to include that influence on contaminant fate and transport in a reservoir.
Need and Benefit
Developing advanced surface water management tools is paramount to Reclamation's ability to reliably deliver water and generate power effectively. Reclamation must also understand the impacts of its project operations and resulting water quality implications to the surrounding ecosystem, particularly for threatened or endangered species.
Quantitative models are powerful tools that can providing spatial and temporal information about ecosystem responses to a perturbation. Current models can represent the water quality aspects of reservoirs. However, toxic metal fate and transport and how the other water quality constituents affect the bioavailability and bioaccumulation of toxics within the system is not included in these models. The premise for selecting a single tool for use by Reclamation and other interested parties is to save on duplicate efforts and consolidate the knowledge base in studying these resources. This type of approach has the potential to be cost effective in modeling the reservoir for many purposes with the ability to incorporate information as it is developed. The use of one tool also eliminates the multi-model conflicts that arise and serves as a foundation of the project, accepted by agencies and stakeholders.
By working with other interested parties, this can become a powerful tool to visualize the cause and effect of actions and work towards acceptable solutions. Ultimately, the model is critical for successfully managing ecosystem health over the long term as a representation of how it responds to natural and anthropogenic perturbations: remediation activities, climate change or operational scenarios. The ELCOM model is a fully three dimensional (3D) hydrodynamic model that simulates water velocity, temperature, and salinity in aquatic systems. The CAEDYM model is coupled to ELCOM and includes detailed biological and geochemical processes. These include: cycling of carbon, nitrogen, phosphorus, oxygen, silica, and metals, aqueous chemical speciation, metal uptake by biota and associated toxicity effects. This model also represents the settling of organic and inorganic particles, fluxes of nutrients and metals across sediment-water interface, growth or inhibition of pelagic species, respiration, and algal succession.
The purpose of this proposal is to investigate the potential for this tool or other tools (GEMSS, MIKE3) that have the capability of accomplishing the proposal objectives and cost effectively incorporate these processes. ELCOM-CAEDYM is currently being developed for Reclamations Deadwood project. It is also currently being used on Lake Coeur d'Alene for analyzing loading and remediation scenarios for zinc and the resulting toxicity effects. This proposal would focus on using Lake Roosevelt as a potential test case, as not all of the metals analyzed in the Lake Roosevelt slag are currently incorporated into the CAEDYM algorithms, nor have they all been tested or validated for a water body. The implications to water delivery and power generation as a result of Grand Coulee Dam operations need to be understood to comply with downstream water quality standards. Reclamation prepared an assessment report in 2002 to evaluate model data requirements and monitoring priorities to support a two-dimensional (2D) temperature model. Seasonal flows, water temperatures, and dissolved gases as well as fish life cycle and migration needs are prominent issues below Lake Roosevelt. Management alternatives need to be evaluated to support both the TMDL and ESA compliance issues. Concurrently, there is a remedial investigation and feasibility study (RI/FS) process developing study plans for the purposes of developing remedial alternatives and implementation plans as a result of Teck Cominco mining activities. Therefore, the ability to acquire or enhance a model that incorporates both of these processes and present visuals of model output scenarios would be an extremely powerful tool.
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