This chapter explains the types of data collected in the Pelican Group of Lakes Improvement District and why each is important. This chapter does not report any of the data, you can find inlet and outlet water quality data in Chapter 8 and lake water quality data in Chapter 9.

Data must be collected to thoroughly diagnose water quality of either rivers or lakes. Usually data must be collected over a prolonged period of time. The environment is never the same every time a test is done. Data is not only collected from the water, but from the water's surroundings as well.

Quality of water can be defined as how it is perceived with our senses, as well as its relationship with the land, fish, and animals. The look, smell, and taste of the water all help define how "good" it is. Also the types and quantity of wildlife help define its quality. Science has located substances in water that can be singled out to define water quality in lakes and rivers. This data is collected by sampling the water at a site and analyzing it in a lab. Another way to determine quality is to take data inventories. Inventories collect statistics on areas, animals, lands, measurements, and other things. These statistics can be used for comparisons and trends.

All popular forms of data are collected and analyzed to ensure accuracy, thoroughness, and quality.

The following subchapters will further identify the type of data, its relation to the water, and how it is collected.

7.1 Flow and Concentration

7.2 Nutrients

7.3 Chlorophyll A

7.4 Secchi Disk

7.5 Temperature, Dissolved Oxygen, and Conductivity

7.6 Toxins

7.7 Trophic State Index

7.8 Eutrophication

A relationship exists between Nutrients, Chlorophyll A, and Secchi Disk. An increase in nutrients equals an increase in chlorophyll A equals a decrease in Secchi disk. A better understanding of this relationship will accrue by reading 7.2, 7.3, 7.4, and 7.7.