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Potential Applications for AQUATOX
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Table of Contents
- Nutrient and eutrophication analysis
- Links between water quality and aquatic life
- Bioaccumulation and ecological effects of organic toxicants
AQUATOX has a myriad of potential applications to water management issues and programs, including water quality criteria and standards, TMDLs (Total Maximum Daily Loads), and ecological risk assessments of aquatic systems. AQUATOX can be used to predict ecological responses to proposed management alternatives. It may help to determine the most important of several environmental stressors, e.g. where there are both nutrients and toxic pollutants.
The choice of an appropriate model or other tool depends upon the kinds of questions to be answered, the complexity of the situation, and the consequences of the outcome. AQUATOX should be considered where the user needs to understand the processes relating the chemical and physical environment with the biological community.
- Where ecological and biological processes are complex
- Where indirect effects are important but difficult to monitor
- When one needs to articulate linkages between nutrients and biotic community
- Where the environmental conditions may change appreciably
Nutrient and eutrophication analysis
Modeling Dissolved Oxygen in AQUATOX
Modeling Nutrients in AQUATOX
Modeling Phytoplankton in AQUATOX
Predict response to nutrient reduction:
DO in hypolimnion with and without WWTP effluent
AQUATOX is well suited for analysis of waterbodies under stress from nutrient enrichment, such as nuisance algal blooms. Potential applications would include development of water quality criteria for nutrients, TMDLs, and analysis of management alternatives.
AQUATOX simulates numerous inter-related variables important in nutrient and dissolved oxygen dynamics, and their effects on the resident aquatic life.
- Nitrogen (total, nitrate, ionized and un-ionized ammonia)
- Phosphorus (total, total soluble phosphate)
- Dissolved oxygen
- Algal biomass, chlorophyll a
- Periphyton biomass in streams
- Macrophytes
- Secchi depth (a measure of water clarity)
AQUATOX is applicable to vertically stratified lakes and reservoirs.
- Simulates stratification and differing conditions in each layer
- Simulates multiple types of phytoplankton, so that it can predict successive blooms throughout season
See Modeling Periphyton with AQUATOX for more details.
Model Validation Reports for details on applications of AQUATOX for nutrient analysis in Onondaga Lake, New York and Coralville Reservoir, Iowa.
AQUATOX can model streams.
- One of the only water quality models that simulates how periphyton (attached algae) respond to nutrients, grazing, and flow
- Simulates macrophytes
- Simulates multiple types of benthic invertebrates and fish
AQUATOX was successfully calibrated and validated against independent data in Walker Branch, Tennessee (PDF) (238 K) to simulate periphyton responses to nutrients, heavy grazing by snails, and variable flow. AQUATOX can be used to evaluate ecosystem responses to proposed control actions.
Links Between Water Quality and Aquatic Life
Aquatic Life Effects
Predict relative abundance of algal groups
Unlike most water quality models, AQUATOX treats the biota as integral to the chemical/physical system. It has potential applications in analyzing the cause and effect relationships between the chemical and physical environment and biological responses.
AQUATOX represents the effects of nutrients and organic toxicants on the aquatic life.
- Simulates the trophic (feeding) relationships within the biological community
- Simulates the direct and indirect effects of stressors
- Articulates ecological linkages
- Calculates time varying ecological and biological processes
- Relative importance of biotic groups
- Test sensitivity of biological responses to individual stressors
- Analyze contributions of multiple stressors
The Model Validation Report for Coralville Reservoir (PDF) (1.0 Mb) includes analysis of the biological community.
Bioaccumulation and ecological effects of organic toxicants
Bioaccumulation in AQUATOX: Organic Toxicants
AQUATOX has the ability to model bioaccumulation of organic toxicants, as well as their direct and indirect effects on the biota.
- Partitioning to water, sediments and biota
- Toxic organic chemical transformations
- Dietary uptake and food web biomagnification
- Calculation of bioaccumulation factors
- Toxic effects on biota, and subsequent effects on food web.
The Model Validation Report for Lake Ontario (PDF) (1.8 Mb), includes computation of bioaccumulation factors and comparison with two other bioaccumulation models.