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Natural vs. Modified Habitat Primary Headwater Habitat Streams

Natural vs. Modified Habitat Primary Headwater Habitat Streams. Headwater Habitat Evaluation Index. What qualifies as a Natural PHWH stream?. Characteristics: A Watercourse with: A defined BED and BANK Either continuous or periodic FLOWING water

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Natural vs. Modified Habitat Primary Headwater Habitat Streams

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  1. Natural vs. Modified HabitatPrimary Headwater Habitat Streams Headwater Habitat Evaluation Index

  2. What qualifies as a Natural PHWH stream? Characteristics: A Watercourse with: A defined BED and BANK Either continuous or periodic FLOWING water A drainage generally LESS than one square mile Deepest pools < 40cm Widely divergent communities based upon in stream Biology No Channelization1

  3. What do Natural PHWH streams do? • Major Downstream Exports: • Desirable Biomass1 • (fish, plants, birds, mammals, sensitive species) • Low Sediment2 Delivery • Water Quality Suitable for ALL Uses Un-impacted PHWH Stream

  4. What qualifies as a Modified PHWH stream? Characteristics: A Watercourse with: A channelized or moved course Man-made ditches Silt infilling Erosion1 No flowing water A filled or buried bed Increased sunlight from vegetation removal Chemical pollution

  5. What do Modified PHWH streams do? Major Downstream Exports • Nutrients & Undesirable Biomass (algae, detritivores1, tolerant2 species) • High Sediment Delivery Degraded3 PHWH Stream

  6. A Natural Primary Headwater Stream PHWH (Class III)

  7. A Modified Primary Headwater Stream PHWH (Class I modified)

  8. Natural over Modified PHWH(Upland Benefits) Increases land value Reduces erosion Reduces or prevent flooding Increases wildlife habitat Increases beauty

  9. Natural over Modified PHWH(Downstream Benefits) Reduces flooding & channel scour1 (energy) Processes nutrients & sediment Protects downstream ecology & water quality Protects drinking waters supplies

  10. Consequences of Continued Degradation of PHWH Streams -Increased degradation of larger streams -Increased maintenance costs -Decreased wildlife habitat -Other consequences

  11. Glossary Biomass - the total living biological material in a given area or of a biological community or group - biomass is measured by weight, or by dry weight per given area (usually measured per square meter or square kilometer) Channelization - the process of reconstructing the natural course of a stream in order to make it flow into a restricted path Degradation - The wearing down of the land by the erosive action of water, wind, or ice Detritivores - Animals that consume decomposing organic materials and in doing so contribute to decomposition and the recycling of nutrients Dry Weight - the weight of the material minus the weight of water in the material - dry weight is often calculated by drying material until it no longer loses weight due to evaporation Encroached - To advance beyond proper or former limits

  12. Glossary - continued Entrenched - Established firmly and securely Eroding - displacement of solids (soil, mud, rock and other particles) by the agents of ocean currents, wind, water, or ice by downward or down-slope movement in response to gravity or by living organisms (in the case of bioerosion) Scour - Debris flows and floods may also occur when strong rains on hill or mountain slopes cause extensive erosion and/or what is known as "channel scour" Sediments - the matter that settles to the bottom of a liquid - in streams the sediments are the suspended particles that settle out when flow stops Tolerant Species - species that are able to tolerate environmental conditions or physiological stress, showing the capacity for endurance

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