Leelanau Conservancy Report of the Leelanau Watershed Council: Water Quality Monitoring Report (A Synthesis of Data from 1990 through 2001)

Abstract

Whenever discussing water quality and this program, we feel compelled to offer a definition of water quality and then explain how it is monitored. Part of that explanation will include a review for some and an introduction for others to some of the underlying limnological (study of freshwater) concepts, as they relate directly to why we measure what we measure and how we interpret those measurements. The interpretation of data for individual lakes can be found following a brief review o f our methodology. A simple understanding of these concepts will provide you with the necessary background to better comprehend our interpretations of the data. So, what is “water quality”? It is likely that there are as many interpretations or definitions as there are users of the concept. Therefore, we offer the following definition: water quality reflects the composition of water as affected by the sum of natural processes and anthropogenic activities, expressed in terms of measurable quantities and related to intended use. That is, water bodies integrate all of the forces acting upon them, whether natural (such as direct precipitation, sunlight, etc.) or unnatural (septic leakage, fertilizer runoff, etc.). By measuring scientifically accepted variables (such as dissolved oxygen, phosphorus, etc.) whose values can be compared with a given set of standards, one can determine if the quality o f a given water body is acceptable for an intended use (such as the public water supply versus recreational activity).