Is your stream stressed?

StreamKayakMinnRiver530Identifying factors that harm fish and other stream life is a key part of the watershed restoration and protection projects being carried out by the MPCA under Minnesota’s Clean Water Legacy Amendment.

The MPCA will be working in several streams throughout Minnesota each year to gauge stream health. Many streams suffer from stressors that harm fish and other aquatic life. These stressors may also affect recreation such as swimming and fishing.

Elements of stream health

The MPCA and local partners examine several interrelated factors to identify stressors. The goal is to maintain conditions in healthy streams and fix problems in unhealthy streams.

The agency studies the following factors and relationships among them:

  • Stream connections, such as dams, culverts and tile drainage
  • Hydrology, including stream flow and runoff
  • Stream biology, such as fish and bugs
  • Water chemistry, including oxygen levels, nutrient levels and temperature
  • Stream channel assessment, mainly erosion

What conditions stress our streams?

StreamStressors-4Too much sediment

Soil and other matter in water can make it hard for fish and other aquatic life to breathe, feed and reproduce. Sediment can also cover spawning areas and fill in parts of streams.

Low oxygen

Aquatic life needs oxygen dissolved in the water to breathe and survive.


Stream temperature affects metabolism and the ability to get oxygen, especially for species such as trout.

Lack of habitat

Habitat affects all aspects of survival for fish and other aquatic life. Habitat encompasses places to live, food to eat, places to reproduce and means of protection.

Too many nutrients

Excess nutrients, such as phosphorus and nitrates, can be toxic to aquatic life and cause algal blooms.

Technical guidance

Local partners may find this technical guidance useful for stressor identification work.

Stressor reports