Excessive sediment can negatively affect streams and the aquatic life that inhabits them. Murky, sediment-laden water can make it difficult for natural vegetation to grow and for fish to find food.  

Sediment particles vary in size, weight, and movement. These particles can be small, light, and easily transported. Or they can be heavy, sandy, and remain close to the streambed. Certain contaminants like copper and other metals are more likely to attach to the surface of small particles and clay than to heavy, sandy sediments. 

We collect data on sediment that’s hanging about – or suspended – in stream water.  Water resource managers and other professionals use estimates of the suspended sediment in a stream to understand contamination, streambank stability, the infilling of reservoirs, and many other purposes. 

When research questions have different purposes, they can require different methods. Our research is on the cutting edge of estimating suspended sediment in streams and rivers. Two recent projects had very different objectives. One documented a new, inexpensive method of sediment collection. The other aimed to understand the metal contamination downstream from former gold, silver, copper, and lead mines. 

USGS scientists at the Upper Midwest Water Science Center developed a new technique to estimate suspended sediment concentration, known as the depth-integrated grab (DIG) method. It is time-saving, inexpensive, and includes the sandier sediment at the bottom of the stream. 

USGS scientists at the Wyoming-Montana Water Science Center used a high-resolution monitoring tool intended to capture the small particle portion of sediment transported by a stream. Sites for this study were near historic metal mining operations, which resulted in the deposition of large amounts of waste materials enriched with metallic contaminants in nearby streams. This monitoring tool is effective in determining the presence of metal contamination.  

So, whether it is the DIG method in Minnesota, or the high resolution monitoring tool in Montana, USGS scientists are leading the way in suspended-sediment science. Read the full publications linked below to discover the findings of these studies.

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