USGS Home
Contact USGS
Search USGS

Search fish passage bibliography

Karr, J. R. (1999). Defining and measuring river health. Freshwater Biology. 41:221-234.

Society benefits immeasurably from rivers. Yet over the past century, humans have changed rivers dramatically, threatening river health. As a result, societal well-being is also threatened because goods and services critical to human society are being depleted. 'Health' - shorthand for good condition (eg healthy economy) - is grounded in science yet speaks to citizens. Applying the concept of health to rivers is a logical outgrowth of scientific principles, legal mandates, and changing societal values. Success in protecting the condition, or health, of rivers depends on realistic models of the interactions of landscapes, rivers, and human actions. Biological monitoring and biological endpoints provide the most integrative view of river condition, or river health. Multimetric biological indices are an important and relatively new approach to measuring river condition. Effective multimetric indices depend on an appropriate classification system, the selection of metrics that give reliable signals of river condition, systematic sampling protocols that measure those biological signals, and analytical procedures that extract relevant biological patterns. Communicating results of biological monitoring to citizens and political leaders is critical if biological monitoring is to influence environmental policies.