Environmental Services Program

Biological Assessments

Drawing of a crayfish.The Missouri Department of Natural Resources initiated the process of biological criteria development in 1992. Biological criteria development consisted of delineating aquatic ecoregions of Missouri, designating reference streams, surveying the habitat and macroinvertebrate communities, selecting and calibrating biological metrics, developing a framework for numeric biological criteria, and establishing numeric criteria for wadeable, perennial streams of Missouri. Using general guidance from the U.S. Environmental Protection Agency, the Department of Natural Resources, University of Missouri - Columbia and Missouri Resource Assessment Partnership researched and developed a biological criteria framework for the wadeable, perennial streams of Missouri. Missouri consists of 19 aquatic ecoregions, termed ecological drainage units. Within these ecological drainage units are 62 wadeable, perennial reference streams which are designated as cold water or warm water, and riffle/pool or glide/pool stream types. Ecological drainage units, in combination with stream type and season, provide a framework for which numeric criteria are generated for 50 categories of streams. Narrative portions of biological criteria were established in the 1994 revision of the Missouri Water Quality Standards. Numeric biological criteria for benthic macroinvertebrates were researched from 1992 through 2002 and reported in the 1997 University of Missouri document:Biological Criteria for Streams of Missouri and the 2002 Department of Natural Resources document: Biological Criteria for Wadeable/Perennial Streams of Missouri. Numeric criteria continue to be refined as reference stream data is collected .

Biological Assessment Reports

Searchable Databases:

Macroinvertebrate samples are collected by the department and other qualified groups using standard operating procedures. A set of four metrics are calculated and translated into a multi-metric index. The multi-metric index scores are grouped into three categories:
20 -16 = fully biological supporting; 14 - 10 = partially biological supporting; and 8 - 4 = non-biological supporting. These categories apply to the support of the designated use of protection of aquatic life.

Biological criteria are narrative descriptions and/or numerical values that describe the reference aquatic communities inhabiting waters that have been given a designated aquatic life use.  The Missouri Department of Natural Resources’ primary intended uses of biological criteria are:

1) to establish regional attainment goals that are relevant to aquatic life use and resource protection;

2) to serve as a scientifically valid benchmark and;

3) to provide a sound scientific basis for biological assessment of the status of aquatic communities.