|Forest Investment Account (FIA) - Land Base Investment Program|
|FIA Project 6738002|
|Stream Restoration Level 1 Overview Assessments (Orford River)|
|Project lead: Robertson, Ian (Forsite Consultants Ltd.)|
|Contributing Authors: Ebell, John; Smith, A.; Meggs, Jeffrey M.; Cuthbert, I.D.|
|Subject: Forest Investment Account (FIA), British Columbia|
|Series: Forest Investment Account (FIA) - Land Base Investment Program|
|Historically, the Orford River watershed produced abundant salmonid stock that supported local First Nation communities and a highly productive ecosystem. Over the last few decades, however, stocks have suffered significant declines and are now at their lowest levels. A century of forest harvesting focused within the environmentally sensitive valley bottom had greatly reduced fish habitat qualities, this condition along with historic over fishing and poor ocean survival as lead to the population declines. |
The last assessment of fish habitat conditions in the Orford watershed was conducted 10 years ago. A number of watershed assessments have reviewed various upslope and instream aspects of the watershed function to varying degress over the past twelve years, finding that reduction in habitat quality from pre-Forest Practice Code logging and road construction has been extensive. Numberous recommendations for hill slope, riparian and instream fish habitat restoration have been provided in these assessments, but few of thesee have been implemented.
This study provides an assessment of current watershed conditions, including a detailed assessment of fish habitat conditions, in order to identify the watershed processess that have been altered by forestry activities and that are limiting fish productivity. Recommendations are provided for the effective restoration on impaired watershed components, as well as enhancement of instream and off-channel salmonid habitat.
Instream fish habitat assessment focused on the anadromous reaches of Orford River and Algard Creek, concluding that a lack of riparian cover, and increased bed-load have reduced fish habitat quality and quantity. Thi shas particularly been the case in Algard Creek which functions as the primary production area for chum salmon. Increased bed-load has reduced channel entrenchment, increasing bank erosion and resulting in further bed-load contributions.
The capture and storage of bed-load has been diminished by an absance of old growth large woddy derbis. LWD is primarily composed of alder logs, offering short-term and limited scout potential for creating and maintaining pool sites and hydraulic diversity. It can be expected that fish egg to fry survival has been poor in such mobile channel bed materials, and where san and silts smother gravels and substates become ember and hardened.
Off-channel habitats have also been impacted by historic forest harvesting. Flood channels and relic channels in the broad alluvial valley bottom have been impacted by cross-stream yarding, sediment runoff and road construction. Stream channels that were historically deeply-entrenched and stable have been replaced by silty, infilled and poorly defined drainages flowing though alder or young mixed forest land. These changes have reduced the extent of suitable habitat for spawning and rearing for chum and coho salmon and cutthroat trout. High-water refuge has also been reduced as access to habitat has declined along with available wetted area.
More then forty opportunities for habitat enhancement and restoration have been identified in this study. The urgent need to deativate the Branch 1000 forest road network upslope and the anadromous reaches of Algrad Crees is highlighted. This system of roads was assessen in 2007 to be at a 'high' risk of failure with potential to deliver tens of thousands of cubic meters of coarse sediment directly into both the Algrad Creek and the DFO-constructed Orford River side-channel. A substantial and potentially permanent decline of the chum salmon population could result from such an event. Chum spawning habitat in Algard Creek is also threatened by a potential channel avulsion through to Orford River, which could eliminate 1.100 lineal maters of Reach 1A, the highest quality chum spawning habitat in the watershed.
Many of the restoration opportunities identified in this study focus on the construction and habitat complexing of off-channel wetted areas to provide stable and secure spawning habitat for chum and coho salmon, as well as quality rearing habitat for coho salmon and cutthrough trout. The need for riparian restoration is urgent, with the objective to shift large areas of alder dominated stands to mixed conifer forests. The need for instream habitat restoration is discussed; however channel instabilit and ongoing rishs of upslope failure limit these opportunities at this time. Simple maintenance and enhancement needs are identified for existing stock enhancement facilities operating in the valley. Additional field samplinng is recommended to confirm the extent of anadromus fish access in the Orford River watershed.
We consider chum salmon to be the hey-stone species required for the overall ecological integrity and health of the terrestrial and aquatic ecosystems in the watershed. Bears, forest land, species diversity and other salmonids are dependant upon their productivity. Many opportunities exist in the valley for salmon habitat restoration and enhancement. Implementation of thes opportunities in concert with the existing stock enhancement program will ensure critical salmonid populations are re-established. Without these measures, salmon stock recovery in the Orford River watershed may be doubtful.
|Final Report (11.5Mb)|
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Updated August 16, 2010
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