An intensive survey of the Vermilion River Basin (Wabash River drainage) 1997 : data collection methods and summary /

"The Illinois Environmental Protection Agency monitors surface waters (i.e. lakes and streams) through a variety of programs. The most extensive is the Ambient Water Quality Monitoring Network (AWQMN) which consists of 203 stream stations statewide sampled on a 6 week cycle since October 1977." -- p. 1.