Illinois EPA Ambient Lake Monitoring Program (ALMP): lake water chemistry, 2001-2004

The Illinois EPA’s Ambient Lake Monitoring Program (ALMP) was created in 1977 in
cooperation with the IL Department of Conservation to assess trends in a select few IL public
lakes. The Illinois EPA biologists work out of three Illinois EPA regional offices: Springfield,
Marion, and Des Plaines and monitor lakes in their respective areas. Approximately fifty lakes
are monitored annually and of those, twenty-five are termed “Core Lakes”. A total of
75 publicly-owned lakes were chosen throughout the state of Illinois as Core Lakes. Previously
these lakes were monitored every three years in order to establish a long-term monitoring trends
database. In 2008 these lakes and select others were monitored on a five year rotational basis.
All lakes are monitored five times yearly; once during the spring runoff and turnover period
(April or May), three times during the summer (June, July, August), and once during the fall
turnover period (October). Depending on the size of the lake, usually three lake sites are
monitored. Monitoring includes collection of water quality and sediment samples as well as,
field observation data/measurements such as Secchi disk transparency readings, dissolved oxygen,
temperature, quantity of algae, macrophytes, and other key aspects of the lake and sampling
event. Water quality samples are collected from one foot below the surface at all sites and two
feet above the bottom at only the deepest site. These samples are routinely analyzed for
suspended solids, nutrients, and chlorophyll. Additional parameters may be added for a
designated period of time at select lakes based on changing data needs.