Sediment Loading Assessment in the Nemadji Basin (USGS 9KP66)

Purpose

The Wisconsin Department of Natural Resources (WDNR) was funded by the USEPA in 2015 to conduct an assessment of the Excessive Loading of Sediment and Nutrient beneficial use impairment (BUI 6) in the Nemadji River basin. As part of that 2-year grant, the US Geological Survey (USGS) will collect suspended sediment concentration (SSC) and bedload data, develop a sediment/discharge rating curve, review historical sediment data, and provide a report summarizing modern average sediment loads on the Nemadji River compared to historical loads. A modern ongoing suspended sediment dataset collected by the Minnesota Pollution Control Agency (MPCA) includes 6 years of event-based total suspended solids (TSS) sampling with approximately 25 samples each year. However, suspended sediment loads based on TSS data are likely underestimating the actual suspended sediment load (Ellison et al., 2014). In order to be able to use the contemporary TSS dataset, the USGS will collect suspended sediment concentration data and develop a calibration relation with TSS data and calculate a modern suspended sediment load as well as bedload and total sediment load. These modern loads can be compared to previous loads calculated in the 1990’s in the Nemadji Basin Plan using sediment monitoring data from the 1970’s (NRCS 1998). The results from the comparison will be used to identify if sediment loading is increasing, decreasing, or similar to the late 1900’s.

Objective

Calculate a modern sediment load for the Nemdaji River at its mouth. The results from the comparison will be used to identify if sediment loading is increasing, decreasing, or similar to the late 1900’s.

Related Reports

Run Project Summary Report
View Umbrella-Projects
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Great Lakes Restoration Initiative
Toxics and Areas of Concern
Nemadji_BUI6_B
2015
Complete
 
Reports and Documents
Q1 2017 quarterly report
Q3 2016 Quarterly Report
Q2 2016 Quarterly Report
Q1- 2016 Quarterly Report
). The lower portion of the Nemadji watershed is situated in extremely clay-rich glaciolacustrine soils (Lake Superior Red Clay Plain) that are naturally prone to erosion and mass wasting. The upper third of the basin is situated in interbedded glacial tills and beach and outwash sands and gravels. Land use changes in the past two centuries have resulted in hydrologic alterations and accelerated erosion rates in similar rivers in Wisconsin situated in the Red Clay Plain (e.g. Fitzpatrick et al 1999, Fitzpatrick and Knox 2000).
Nemadji Sediment Load QAPP Final