Water quality has been consistently ranked as the top priority by respondents to MLA several surveys and studies. As a result, Water Quality initiatives figure prominently in the list of Action Items included in the MLA Lake Plan, launched in 2015. Each year, the MLA publishes a State of the Lake Report to keep our membership aware of current water quality, and historic trends.
Water Quality Sampling
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.
The MLA provides staffing and funding for water sample collection, while MVCA funds the laboratory analysis costs as part of our joint commitment to collect frequent and regular water quality information. This allows us and our partners, to understand annual and longer-term water quality variations in the lake and how these may impact aquatic vegetation and algae growth, fish, waterfowl and other species, as well as our enjoyment of the lake.
Water sampling includes measurement of:
a. total phosphorus, since elevated phosphorus concentrations are a major factor in promoting plant growth and algae blooms;
b. water clarity, which is primarily affected by the amount of suspended algae, using a Secchi Disc; and
c. 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.
The Table below 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.
Lake Trophic Status