Comprehensive water quality monitoring is necessary to improve natural resource management, maintain sustainable ecosystems, and protect public health. The State of Michigan has more than 76,000 miles of streams and rivers, and assessing the condition of these valuable water resources is a major focus of EGLE’s monitoring effort. To ensure adequate coverage of our large number of rivers and streams, EGLE’s water quality monitoring is implemented according to a 5-year rotating watershed cycle. Michigan has 57 major watersheds based on the USGS’s 8-digit Hydrologic Unit Codes. Assessment efforts focus on a subset (approximately 20 percent) of these major watersheds each year.

EGLE’s stream and river sampling includes the following components:

• Wadeable streams and rivers: Biological and habitat sampling is conducted using EGLE’s Procedure 51. P-51 includes multi-metric indices for fish and benthic macroinvertebrate communities, as well as habitat quality.
• Nonwadeable rivers: Biological and habitat sampling is conducted using the EGLE's Procedure 22. P-22 includes multi-metric indices for benthic macroinvertebrates and river habitat.
• Fixed station tributary rivers: From 1998-2013, multiple water samples were collected each year from 31 Great Lakes tributaries in Michigan.  Samples were analyzed for nutrients, metals, sediments, cations, and anions.
• Connecting channels: Since 1998, water samples have been collected each year from an upstream and downstream location in the St. Marys River, St. Clair River, and the Detroit River. Samples are analyzed for nutrients, metals, sediments, cations, and anions.
• Random sampling: EGLE uses a probabilistic approach to monitoring water quality, sampling 50 sites each year over a 5-year period, for a total of 250 sites. Thus far, we have completed two cycles (2005-2009, 2010-2014).  Water samples are analyzed for conventional parameters, nutrients, sediments, and low-level mercury and other trace metals.
• Targeted monitoring: Each year, EGLE solicits monitoring requests from within EGLE, other state and federal agencies, as well as the public.  Requests are reviewed and prioritized based on the objectives, 5-year watershed cycle, and available resources (staff and funding).  These requests support EGLE's water related programs (NPDES, Non-point Source, TMDLs, etc.), and respond to local water quality concerns, and provide information to define problems and evaluate success of pollution control efforts.  Monitoring activities responsive to these requests include chemical, physical, and biological assessments.
• Volunteer monitoring: EGLE provides financial support to the Great Lakes Commission to administer the MiCorps volunteer monitoring program.  One component includes the monitoring of benthic macroinvertebrates and habitat in wadeable streams and rivers. Some volunteers also conduct road stream crossing surveys to identify potential problems in a watershed.
• Fish contaminants: EGLE, in cooperation with the MDNR-Fisheries Division, collects fish from fixed stations and targeted locations in streams and rivers each year for contaminant analysis.  Tissues are typically analyzed for organic contaminants (e.g. PCBs, DDT) and mercury to evaluate the need for consumption advisories and to assess trends over time.

Other agencies also conduct extensive stream and river monitoring activities in Michigan including the Michigan Department of Natural Resources (fish assessment), USEPA (National Rivers and Streams Assessment), and the U.S. Geological Survey (flow monitoring, NAWQA, special studies).