Download presentation
Presentation is loading. Please wait.
1
Common Stream Habitat Problems
Unstable “flashy” flows (Hydrology) Temperature extremes Unstable banks and severe erosion Low habitat complexity Sedimentation Nutrient loading and eutrophication Inadequate refuge habitat (temperature, flows, predators) Inadequate spawning habitat Inadequate foraging habitat Blocked migration routes (Connectivity)
2
Channel Incision
3
Bank Instability
4
Stream Habitat Management
5
Culverts and Passage
6
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.
7
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.
8
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. The science of restoration ecologically is much more practical, however, and it recognizes that there are levels of “restoration” that may be achieved. LEVEL ONE IS UNLIKELY BECAUSE OFTEN WE DON’T KNOW WHAT IT WAS LIKE (CAN BE VIEWED AS UNATTAINABLE IN A PRACTICAL AND METAPHYSICAL SENSE). LEVEL TWO IS MUCH MORE LIKELY BUT ONLY WHERE SOCIO ECONOMIC ISSUES ARE LARGELY ABSENT “PREDETERMINED” IS AN IMPORTANT WORD. WE ARE PLACING OUR OWN VALUATION ON THE STATE OF STRUCTURE AND FUNCTION THAT WE THINK SHOULD BE PRESENT. LEVEL THREE IS THE MOST COMMON, ESPECIALLY IN HIGHLY IMPACTED AREAS
9
GENERAL RESTORATION APPROACHES
APPROACH I: Non-Intervention and Undisturbed Recovery APPROACH II: Partial Intervention for Assisted Recovery APPROACH III: Substantial Intervention for Managed Recovery Within each of the restoration levels, one can choose among 3 types of restoration or 3 general restoration approaches.
10
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 Ideal approach, cheapest and it lets nature take care of itself. Important to remember that removing human-induced disturbances from the watershed is critical to the self-healing process.
12
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. Ideal approach, cheapest and it lets nature take care of itself. Important to remember that removing human-induced disturbances from the watershed is critical to the self-healing process.
13
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. Ideal approach, cheapest and it lets nature take care of itself. Important to remember that removing human-induced disturbances from the watershed is critical to the self-healing process.
15
I. GOALS III. ASSESSMENT II. OBJECTIVES IV. ACTION V. EVALUATION
Similar presentations
© 2025 SlidePlayer.com. Inc.
All rights reserved.