In 1991, the DOW began a Reference Reach Program to gather data from the state’s least impacted streams. The primary objectives of the Reference Reach Program were to collect and summarize data from least-disturbed streams using a regional framework in order to develop appropriate criteria for bioassessment interpretation.
A firm understanding of the inherent biological variability and natural potential of the streams within a collective region is needed to address levels of impact to any given stream. This is accomplished using a regional reference approach, which is based on the range of natural conditions found in a population of sites or streams with similar physical characteristics and minimal human impact. The reference condition collectively refers to the range of quantifiable ecological elements (i.e., chemistry, habitat and biology) that are found in natural environments.
In many regions of Kentucky, finding reference streams can be a difficult task because no regions are entirely without areas of human disturbance. Biologists first identify potential least-impacted waters representative of geographic regions of the state known as ecoregions. Typical reference reach watersheds contain a high proportion of natural vegetation and have minimal human disturbance such as point-source discharges, agricultural land, mining and urban development. Then, data on chemical water quality, sediment quality, fish tissue residue, habitat condition and biotic conditions are collected to (1) define the potential environmental quality for the streams of a particular ecoregion and (2) allow other streams in the same ecoregion to be compared to the reference condition.
Data from the Reference Reach Program provides the basis for the development of narrative and numerical biocriteria for the various ecoregions of the commonwealth. Because of the significant value the streams within the Reference Reach Network hold, they are protected under the antidegradation policy implementation methodology of Kentucky's Administrative Regulations, 401 KAR 5:030.
Click here to view a map (pdf) of the stream segments and lakes designated as reference in the 2004 regulations, which was the latest publication of that regulation.
