STREAM ECOLOGY By Maggie Bell-McKinnon, biologist Washington Department of Ecology

Why Should We Care About Streams?

Wildlife drink water out of streams.

We like to fish and swim in streams.

Fish and other aquatic animals need good water quality for their homes and for their food.

Stream Structure

Pool

Riffle

Run or Glide

Woody Debris

Stream Discharge - is the total amount (volume) of water flowing in the stream. It is important to know how much water is flowing in a stream because it affects many things about a stream, for example: * Salmon need slower flowing areas of a stream to lay their eggs. * Other aquatic animals (like macroinvertebrates) and algae can’t live in a stream that has water moving too fast.

Stream Discharge – how to measure Stream discharge is measured by multiplying the area of the stream by its velocity. Stream discharge is measured in cubic feet per second (cfs).

Depth Width A Pretend Stream Stream Discharge = Area (A) x Velocity (V) Area (A) = Depth x Width

A Real Stream Stream Area = the area of box 1+box 2+box 3+ box 4+box 5+box 6+box 7+box 8+box 9+box 10

Embeddedness Embeddedness refers to how much the rocks (gravel, cobble, and boulders) are surrounded by, covered, or sunken into the silt, sand, or mud of the stream bottom.

Embeddedness Generally, as rocks become embedded, fewer living spaces are available to macroinvertebrates and fish for shelter, spawning and egg incubation.

Riparian Zone The area between the stream and the land away from the stream. Riparian comes from the Latin word, ripa, which means river bank. Because the riparian zone can flood, the vegetation that grows there must be able to tolerate having its roots get wet occasionally.

Riparian zones are important to a stream because: They filter pollutants and prevent them from entering the stream

Riparian zones are important to a stream because: They prevent the streambank from eroding or wearing away.

Riparian zones are important to a stream because: They supply shade to the stream

Riparian zones are important to a stream because: They provide shelter and food for animals that live in or near the stream

Examples of Riparian Vegetation In a healthy riparian zone, there are typically three layers of vegetation that occur:  Tall trees  Shorter trees and shrubs  Flowering plants and ferns

Douglas fir - Pseudotsuga menziesii

Black cottonwood - Populus trichocarpa

Vine maple - Acer circinatum

Devil’s club - Oplopanax horridus

Slough sedge - Carex obnupta

Food Web

The Sun

Food Web

Black Fly Larvae

Black Fly Larvae on a Rock

Food Web Caddis Fly Larvae

Food Web Caddis Fly Larvae

Food Web Water Louse

Food Web Water Strider

Food Web

Water Quality Parameters Dissolved Oxygen Oxygen in the water comes from the air/ atmosphere and the aquatic plants (through photosynthesis).

Water Quality Parameters Dissolved Oxygen Aquatic organisms – plants and animals – need to breathe oxygen, just like people.

Water Quality Parameters Dissolved Oxygen Dissolved oxygen levels change throughout the day based on water temperature and photosynthetic activity.

Water Quality Parameters Temperature Stream temperature controls how plants and animals live. Warm water contains less dissolved oxygen than cool water.

Water Quality Parameters Temperature Young salmon need temperatures of around 9°Centigrade; adult salmon need water that’s 12°Centigrade.

Water Quality Parameters pH A pH measurement tells us whether a stream is acidic or alkaline. pH values range from 0 to 14; values from 0 to 7 are considered acidic, 7 is neutral and above 7 is considered alkaline or basic. The pH of a stream is determined by what kind of rocks the stream flows over and sometimes by humans.

Water Quality Parameters Nutrients Nitrate is one of the nutrients which is used as food by plants. Nitrates can come from decomposing plants and animals, human sewage, fertilizers and stormwater run- off. Excessive amounts of nitrates can cause too much algae growth. This lowers the dissolved oxygen levels when the algae die and decompose.

Water Quality Parameters Turbidity Turbidity is a measurement of how clear or cloudy the water looks. Water becomes cloudy when it contains solid material. This solid material can be a combination of sediment, algae, aquatic animals - anything that can be suspended in the water. Turbidity can affect the ability of fish to live by clogging their gills.

Water Quality Parameters Bacteria Not all bacteria are harmful to humans but some are, like fecal coliform. These “bad” bacteria produce toxins which make people sick. It is important to protect humans from these harmful bacteria which could occur both in our drinking water as well as in the lakes and rivers where people play and have fun.

What can you do to help a stream?