Common Stream Habitat Problems

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Common Stream Habitat Problems

1. Unstable flashy flows (Hydrology)
2. Temperature extremes
3. Unstable banks and severe erosion
4. Low habitat complexity
5. Sedimentation
6. Nutrient loading and eutrophication
7. Inadequate refuge habitat (temperature, flows,
   predators)
8. Inadequate spawning habitat
9. Inadequate foraging habitat
10. Blocked migration routes (Connectivity)

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Channel Incision
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Bank Instability
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Stream Habitat Management
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Culverts and Passage
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WHAT ARE THE GOALS OF STREAM HABITAT MANAGEMENT?
Protect, Restore, and Improve watershed function
and stream habitat so that diverse natural
habitats, native populations, critical refugia,
and natural ecosystem processes are maintained.
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Stream Habitat Management

• Trend is towards ecosystem management and Natural
  Channel Design (Rosgen)
• Holistic stream management manage for community
  and integrity, not individual species
• Attempt to move degraded streams towards a
  dynamic equilibrium that is structurally and
  functionally similar to reference streams.

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LEVELS OF RESTORATION
LEVEL I FULL RESTORATION Return of a river
ecosystem to a close approximation of its
condition prior to disturbance. LEVEL
II REHABILITATION Return of a river reach to
some predetermined state of structure and
function. LEVEL III NATURALIZATION Shift of
some characteristics of a river closer to a
natural pattern while maintaining or enhancing
economic and social uses of the system.
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GENERAL RESTORATION APPROACHES
APPROACH I Non-Intervention and Undisturbed
Recovery APPROACH II Partial Intervention
for Assisted Recovery APPROACH III
Substantial Intervention for Managed Recovery
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GENERAL RESTORATION APPROACHES
APPROACH I Non-Intervention and Undisturbed
Recovery The stream corridor is recovering
rapidly and active restoration is unnecessary and
even detrimental. Restoration consists of simply
removing or mitigating for key, human-induced
disturbances within the watershed. Examples
controlling storm-water runoff, fencing
streamside management zones, reforestation of
watershed
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GENERAL RESTORATION APPROACHES
APPROACH II Partial Intervention for Assisted
Recovery The stream corridor is attempting to
recover but is doing so slowly or uncertainly.
Remediation action is intended to facilitate
natural recovery processes already occurring.
Restoration actions are designed to facilitate
processes not duplicate them. Examples
planting streamside vegetation, erosion control
devices, limited use of instream structures to
dissipate energy during high flows and enhance
fish habitat.
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GENERAL RESTORATION APPROACHES
APPROACH III Substantial Intervention for
Managed Recovery Recovery of desired stream
functions is beyond the repair capacity of the
ecosystem and aggressive restoration measures are
needed. Remediation actions are designed to
reconstruct a natural dynamic equilibrium to a
damaged stream channel with the idea that natural
ecological structure and function will
follow. Examples modification of channel
geometry and meander profile, design and
placement of instream structures (e.g., j-hooks,
w-weirs, boulder clusters), reshaping and
revegetation of bank, bankfull shelf, and
riparian corridor.
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I. GOALS
III. ASSESSMENT
II. OBJECTIVES
IV. ACTION
V. EVALUATION