Water quality sampling at Mississippi National River and Recreation Area, 2006

Elias, Joan; Sieracki, Jennifer

The Great Lakes Inventory and Monitoring Network (GLKN) began monitoring water quality in the Mississippi National River and Recreation Area (MISS) in 2006. Sampling was conducted monthly at five sites from April through November. In the field, we measured pH, specific conductance, temperature, dissolved oxygen, and turbidity with a multiprobe. We also measured water clarity with a transparency tube and Secchi disk, and recorded environmental conditions, such as weather and flow conditions. Water samples were collected during each sampling period and sent to contract analytical laboratories for analysis of chlorophyll-a, nutrients (total phosphorus, total nitrogen, nitrate+nitrite-nitrogen, ammonia-nitrogen), total suspended solids, dissolved organic carbon, alkalinity, chloride, sulfate, cations (calcium, magnesium, potassium, sodium), and dissolved silica. We also collected surface sediment samples at three sites for analysis of diatom communities, which are a good integrator of water quality conditions. Results of this first year of monitoring indicate MISS waters frequently exceeded U.S. Environmental Protection Agency (EPA) criteria for nutrients and occasionally exceeded state criteria for total suspended solids. Dissolved oxygen concentrations were adequate to support aquatic life, except at one site during one sampling period. Specific conductance and ionic strength of the water is high, as is alkalinity. The site farthest downstream (UM822) showed elevated concentrations of most constituents compared to the four upstream sites. Inputs from the Minnesota River and multiple point sources likely affect water quality at UM822.

Water quality sampling at Mississippi National River and Recreation Area, 2006

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