National Water Quality Program

Regional Stream Quality Assessments

Midwest Stream Quality Assessment: Linking the

landscape, in-stream stressors, and ecology

Major Findings of MSQAExtensive modification of the landscape in the Midwestern United States has profoundly

affected the condition of streams. Row crops and pavement have replaced grasslands and

woodlands, streams have been straightened, and wetlands and fields have been drained.

These actions alter the stream habitat and add nutrients and pesticides to small streams.

The physical alterations and chemicals present are “stressors” that are adversely affecting

the fish, invertebrates, and algae living in small Midwestern streams.

Michael Peirce, Creative Commons 2.0

3

MSQA by the

numbers …• 6 nutrients

• 11 states

• 12 weeks

• 100 streams

• 135 fish species

• 227 pesticides

• 1200 water samples

• 100+ USGS personnel

Fish

• Fish species loss is most related to increases in streambed sedimentation

• Fish also are affected by nitrogen, phosphorus, low dissolved oxygen, and degraded riparian (near-stream) habitat

More sedimentation leads

to a loss of “sensitive” fish

species

Meador and Frey, 2018, JAWRA

Green sunfish

Invertebrates

Mayfly

Zleng, Creative Commons 2.0

Waite and Van Metre, 2017, Freshwater Science

A biologist uses a fine-mesh net

to collect invertebrates from a

stream riffle

• Riparian condition, sediment grainsize, velocity, channel shape, ammonia, and insecticides affect invertebrates

• Mayflies are particularly sensitive to bifenthrin, a pyrethroid insecticide

Algae

Munn et al., 2018, Ecological Indicators

• Habitat, phosphorus, and herbicides are stressors to algal communities

• Streambed sediment size affects algal sensitivity to other stressors: o Algae in streams with fine sediment are affected by water

temperature and herbicideso Algae in streams with coarse sediment are affected by water

temperature and depth

In streams, algae

often grow on rocks.

Algae are sampled

by scraping the rock

surface with a stiff

brush.

“Stream straightening” changes stream habitat by removing riparian woodlands, increasing water velocity and erosion, and decreasing interaction between the stream water and the streambed.

Straightening and loss of healthy riparian habitat are evident in this Google Earth image

from NE Iowa. Streams are visible as light green lines over which a grid of rural roads is

superimposed.

Peter Van Metre

pcvanmet@usgs.gov

http://webapps.usgs.gov/RSQA/

http://water.usgs.gov/nawqa/

https://www.sciencebase.gov/catalog/