Natural vs. Modified Habitat Primary Headwater Habitat Streams Headwater Habitat Evaluation Index

What qualifies as a Natural PHWH stream?  Characteristics: A Watercourse with: 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 Channelization  No Channelization 1

What do Natural PHWH streams do? Major Downstream Exports: 1.Desirable Biomass 1 (fish, plants, birds, mammals, sensitive species) 1.Low Sediment 2 Delivery 2.Water Quality Suitable for ALL Uses Un-impacted PHWH Stream

What qualifies as a Modified PHWH stream?  Characteristics: A Watercourse with: A Watercourse with:  A channelized or moved course  Man-made ditches  Silt infilling  Erosion 1  No flowing water  A filled or buried bed  Increased sunlight from vegetation removal  Chemical pollution

What do Modified PHWH streams do? Major Downstream Exports  Nutrients & Undesirable Biomass (algae, detritivores 1, tolerant 2 species)  High Sediment Delivery Degraded 3 PHWH Stream

A Natural Primary Headwater Stream PHWH (Class III)

A Modified Primary Headwater Stream PHWH (Class I modified)

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

Natural over Modified PHWH (Downstream Benefits)  Reduces flooding & channel scour 1 (energy)  Processes nutrients & sediment  Protects downstream ecology & water quality  Protects drinking waters supplies

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

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

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