Water Testing
Water quality information on Mississippi Lake has been gathered under a variety of programs since 1968, primarily to examine the trophic status of the lake (the amount of biomass present in the lake). Please consult the Table below for definitions of the Status levels.
Water sampling includes measurement of:
total phosphorus, since elevated phosphorus concentrations are a major factor in promoting plant growth and algae blooms;
water clarity, which is primarily affected by the amount of suspended algae, using a Secchi Disc; and
the concentration of active chlorophyll (chlorophyll A), as a measure of the amount of photosynthesizing plants (algae and phytoplankton) in the water.
Sampling programs have also included other water quality parameters such as dissolved oxygen, pH and temperature, although these are not addressed in detail in the annual State of the Lake reports. However, it is reassuring to note that dissolved oxygen measurements have and continue to show life-supporting oxygen concentrations throughout the water profile.
This table indicates how the measurement of total phosphorus concentration, water clarity, and chlorophyll A levels can be used to assess the overall trophic status of the lake. Mississippi Lake, being shallow and having a broad surface area, is subject to excessive aquatic vegetation and algae growth and was considered to be eutrophic in the late 1960’s through much of the 1970’s.
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