Products 
APM lA FY02 Conceptual framework including consideration of both single and multiple 
stressors and cross-scale issues (AED, MED). 
Database structure to support problem formulation in the diagnostic process (303(d) listings) and 
Nation-wide database for stressor-response relationships for non-point source stressors (all 
Ecology Divisions, FY03). 
Benefit of Products 
One of the difficulties in diagnosing the causes of impairment is the lack of an adequate 
information framework to support problem formulation. The APMs for this research area 
provide a conceptual framework for describing stressor-response relationships and an 
information framework for providing geospatial and toxicity data tailored to diagnostic 
applications (e.g., methods and models). Development of the geospatial database support system 
will be coordinated with the OW/OST because NHEERL will be adding to their BASINS 
modeling support system. These APMs will provide State, Regional, and Tribal authorities with 
critical and essential tools, which are currently unavailable, for starting the diagnosis process on 
an impairment problem. Ultimately, these information management tools can be incorporated 
into decision-support systems. 
Project Title 2. Classification Framework 
Project Coordination and Resources (10.6 FTEs: FY03: AED-0.4, GED-2.6, MED-5.0 [total = 
8.0]; FY04: GED-2.6 [total = 2.6]) 
Objectives 
Integrated hierarchical classification schemes will be developed at the scale of habitats, water 
bodies, watersheds, and regions to identify systems that are expected to respond similarly to 
aquatic stressors (see Sections 4-7). For example, estuaries with longer retention times are more 
susceptible to the effects of nutrient loading (Palter and Dettman 1999). The relative impact of 
suspended and bedded sediments via sedimentation and physical habitat alteration versus 
turbidity also will depend on retention time. Even the effect of toxic chemicals can be expected 
to vary systematically depending on physico-chemical characteristics of water bodies and 
sediments such as organic carbon, acid-volatile sulfides, suspended solids, and hardness 
(Hamelink et al. 1994, Bergman and Dorward-King 1997). 
Scientific Approach 
The central question that must be answered to determine if a classification system will be useful 
for diagnosis is, "does grouping of systems by class simplify the problem of determining the 
cause of the observed ecological effects which are equated with an impaired condition of a water 
body?" We propose to answer this question by developing classification systems that are keyed 
to the different levels of a nested spatial hierarchy that proceeds as follows: habitat, water body. 
148 
