GBMSD samples at 18 stations that are located on lower Bay of Green Bay, the Fox River, and East River. 

Sites are divided into the following zones:

• East River - Sites 10, 12
• Fox River above De Pere dam - Station 5
• Fox River below De Pere dam - Stations 7-16
• Zone 1 of Green Bay - Stations 22-32
• Zone 2 of Green Bay - Stations 41-51
• Zone 3 of Green Bay - Stations 55-57

12 sites are sampled weekly within these zones.

Bay of Green Bay

Zone 1 is the area of the Bay that receives discharge from the Fox River.  It has the lowest Secchi depth and highest concentrations of nutrients and sediments.

Zone 2 is a transition zone between zone 1 and zone 3.

Zone 3 is approximately 14 miles north from the mouth of the Fox River and has the best water quality.

Fox River

The Fox River has four stations that are sampled during every water quality survey.  Of these four stations, three are below the De Pere dam and one is located above the De Pere dam.

East River

The East River has two monitoring stations which are sampled during each water quality survey.