Tiered Aquatic Life Uses (TALUs)
As defined: The structure of designated aquatic life uses that incorporates a hierarchy of use subclasses and stratification by natural divisions that pertain to geographical and waterbody class strata. TALUs are based on representative ecological attributes and these should be reflected in the narrative description of each TALU subcategory and be embodied in the measurements that extend to expressions of that narrative through numeric biocriteria and by extension to chemical and physical indicators and criteria.
As used: TALUs are assigned to water bodies based on the protection and restoration of ecological potential. This means that the assignment of a TALU subcategory to a specific waterbody is done with regard to reasonable restoration or protection expectations and attainability. Hence knowledge of the current condition of a waterbody and an accompanying and adequate assessment of stressors affecting that waterbody are needed to make these assignments.
Cover or Structure Metric
A metric of the cQHEI and QHEI that assesses the presence (cQHEI, QHEI) and condition (QHEI) of physical structural components (logs, boulders, undercut banks, root wads, aquatic plants, etc.,) that provide habitat important to aquatic life.
Biological Assessment
An evaluation of the biological condition of a waterbody using surveys of the structure and function of a community of resident biota; also known as "bioassessment". It also includes the interdisciplinary process of determining condition and relating that condition to chemical, physical, and biological factors that are measured along with the biological sampling.
