Agricultural chemicals, human and animal wastes, and road salt are the major sources of chloride in lake water. Green pigment present in all plant life and necessary for photosynthesis. The amount present in lake water depends on the amount of algae and is therefore used as a common indicator of water quality. A yellow-brown natural color is associated with lakes or rivers receiving wetland drainage. The average color value for Wisconsin lakes is 39 units, with the color of state lakes ranging from zero to 320 units.
Color also affects light penetration and therefore the depth at which plants can grow.
Measures water's ability to conduct an electric current. Values are commonly two times the water hardness unless the water is receiving high concentrations of contaminants introduced by humans. The total land area that drains toward the lake. Lakes fed primarily by streams and with outlets into streams or rivers. They are more subject to surface runoff problems but generally have shorter residence times than seepage lakes.