Reference value/conditions

What is Reference value/conditions?

Reference value/conditions meaning
A. A single measurement or set of selected measurements of unimpaired water bodies characteristic of an ecoregion and (or) habitat (USEPA/OST).
B. The chemical, physical, or biological quality or condition that is exhibited at either a single site or an aggregation of sites that represent the least impacted or reasonably attainable condition at the least impacted reference sites (Ohio EPA).


reference: USGS – Glossary of Water-Quality Monitoring Term