Page 8 - 7047 - Healthy Bugs Booklet

TEN INDICATORS OF WATERSHED HEALTH

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total taxa mayflies stoneflies caddisflies intolerant long lived % dominance

clingers % tolerant % predator
When The Problem with Sediment Predators with no place to hunt or

Streams naturally ebb and flow
Water with the rains. Heavy rain can bring hide are lost as sediment increases.
unexpected flooding, and the mud and
When the land near streams is
sediment moved by water is often
developed, the soil is loosened and
more damaging than the water itself,
Moves especially when the flood moves inside can move more easily when it rains. In
contrast, native trees and plants hold
people’s homes.
the soil and creek banks in place and
Sediment causes similar problems for
keep sediment out of the stream.
Dirt the animals living in streams. Fine sand Local building regulations are designed
and sediment can become trapped and
to protect streams, wetlands, and other
fill the open space between rocks and
cobble. Many invertebrates and young
state, streams are classified based on
fish depend on the spaces in between water resource areas. Throughout the
cobble to live and grow. Invertebrate their size and importance to wildlife and
clingers cannot hold onto sand, they people. The level of protection of the
need smooth rock surfaces. Hardy vegetated riparian area is greater for
invertebrates that can survive in the fish bearing streams and less for smaller
water column without rock cover or streams that do not support fish.
in the soft sediment tolerate these
 conditions and increase in number.
water cobble
column 


} fine sediment = lost habitat

Photo: Oregonian

Sediment can fill spaces where baby salmon (alevin) hide Sediment and water from flooding

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