Stream Order

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Stream Order Watersheds
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Watershed

• A ridge of high land dividing two areas that are
  drained by different river systems.
• The region draining into a river, river system,
  or other body of water.

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Watershed
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Stream Order
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Upstream vs. Downstream
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1st order stream (1 stream)
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Characteristics

• Steep angle / high elevation
• Substrate dominated by boulders and cobbles
• Narrow channel
• Usually acidic (low pH - lt7)
• Low biodiversity
• Mostly shredders and gatherers
• High cover - usually shaded
• Low turbidity - clear
• Low temperatures
• High oxygen

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2 stream
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Characteristics

• Formed in a valley
• Less shaded
• Higher temperatures
• Less steep
• Wider
• More nutrients / higher turbidity
• Substrate dominated by cobbles and gravels
• More biodiversity
• Shredders, gatherers, and collectors

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3 Stream
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Characteristics

• Also forms in a valley, where 2 or more 2nd order
  streams intersect
• Higher temperature, less shade, wider channel
• More nutrients, higher turbidity
• Substrate dominated by gravels, sands
• More biodiversity, fewer of each species/type
• Higher pH
• Slower water, less oxygen

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4 and above
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4th Order and Higher

• Gentle slope (1-2)
• Slow water (slack water/glides)
• Finer substrate (mud to gravels)
• Higher turbidity - cloudy (silts clays)
• Higher temperature
• Lower oxygen
• Alkaline (higher pH - gt7)
• More sinuosity
• Wider channel
• Less tree cover more sunlight to creek
• Filtering collecters, scrapers

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Point Source vs. Non-Point Source Pollution
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Why is a watershed important?

• What affects it?
• Who owns it?
• What is affected by it?
• Who lives in/near it?