Risk = Hazard x Consequence

Transcription

1 Tolko Industries Ltd. Cariboo Woodlands Forest Stewardship Plan Major Amendment 26 Watershed Hydrology 1. Introduction: The Cariboo Chilcotin Land Use Plan (CCLUP) and current Tolko Forest Stewardship Plan (FSP) carry requirements to manage watersheds for the purposes of hydrologic stability and/or the conservation of salmon stocks. These requirements in the FSP have historically utilized an Equivalent Clearcut Area (ECA) threshold of 25% as a trigger for further detailed watershed assessment. Although ECA represents a relatively easy indicator to measure, across large areas, it does not necessarily correspond to actual watershed risk (Pike et al. 2010). A more holistic approach to watershed management is proposed in order to support Tolko Industries Ltd (Tolko) in the continued implementation of watershed management during timber development planning. The project area within the scope of this FSP Amendment is comprised of Key Watersheds including the Cottonwood, Quesnel (including Horsefly and Cariboo), Bridge and Bonaparte River Watersheds. Basins and sub-basins are identified as Key Watershed Reporting Units to allow for the assessment of hazards, fish values and risks at different scales. The changes proposed as part of this FSP amendment include the following items discussed in more detail below: Revised FSP Watershed Boundaries Replace FSP Strategy for Hydrological Stability Revise FSP Result/Strategy for Salmon To support review and comment on this FSP amendment a brief overview of the risk rating process is provided under section 2.0 below for context. 2. Background on Watershed Risk to Fish Values: How best to manage and conserve fish and fish habitat is a key question in forest and land management in B.C. Prioritizing management strategies based on current or anticipated risks can be used to maximize benefits to fisheries values while minimizing impacts on forest development. To do this, forest and land managers must understand: 1) fish and fish habitat values, 2) current and proposed development on the land base, 3) potential effects of planned development on watershed condition, and 4) the efficacy of the proposed management. By developing this understanding, key issues can be identified and management strategies can be focused to ensure meaningful benefits to fish and fish habitat. Risk - Risk can be defined as the combination of the likelihood of an event occurring (hazard) and the impact the event will have (consequence). The proposed FSP strategy under this amendment is based on the following risk based assessment: Risk = Hazard x Consequence Consequence - Identifying consequences or fish values at risk is an important step in understanding the overall risks within a watershed. Understanding fish values generally involves identifying fish presence, species, abundance, life stages, and location and duration of habitat use. Hazard - Hazards that impact fish and fish habitat are generally associated with changes to the streamflow regime (e.g. increased magnitude or frequency of peak streamflows), sedimentation and/or loss of functional riparian vegetation. The hazard indices can be defined as follows:

2 Streamflow Hazard: the likelihood that peak flow (magnitude and frequency) has been increased by forest cover disturbance. Sediment Hazard: the degree to which human activity has increased the rate of sediment supply to the stream network, relative to background rates. Riparian Function Hazard - the degree to which natural riparian function has been disturbed. The 3 hazard indices are combined to derive an overall hazard for the area in consideration. An assessment of hazards must consider both natural conditions and land use effects on watershed condition. 3. FSP Watershed Boundaries: The proposed FSP strategy under this amendment will be applied to the following Key Watersheds: a) Watersheds designated as hydrologically sensitive in the Cariboo Chilcotin Land Use Plan, including the following: Cottonwood River Cariboo River Horsefly River Bridge Creek Bonaparte River b) The remainder of the Quesnel River watershed identified as a watershed of significance for Salmon in the CCLUP. Currently in the approved FSP the watershed area that the strategy is applied to is identified on map #1. Under FSP Amendment 26 the proposed watershed area that the strategy will be applied to is identified on map #2. The CCLUP speaks to the issue of scale by referencing the need to manage watershed risk factors within the main basins of the Key Watersheds. To this end, the assessment of watershed risk at the Basin and Sub-basin level is being proposed (refer to map #3) under the strategy. An additional consideration will apply beyond the Basin and Sub-basin level under this FSP Amendment including: Residual Areas are those areas within Key Watersheds that are not covered by the defined Basins or Subbasins (refer to map #4). To this end, special management considerations are proposed as part of the strategy for this FSP amendment for residual areas. 4. Proposed FSP Strategy Hydrological Stability: Through the implementation of the CCLUP, timber development within both hydrologically sensitive watersheds and salmon-bearing watersheds must consider risks to fish and fish habitat. The proposed FSP strategy below was developed to meet this requirement and is intended to replace what is currently approved in the FSP:

3 1. When primary forest activities are planned within Key Watersheds, each holder of this FSP will: a. Where the Net Watershed Risk for the relevant Key Watershed Reporting Units as supported by the current Risk Rating Table is: i. LOW, conduct activities in accordance with section of this FSP, or ii. MODERATE, a Qualified Professional will complete a Preliminary Risk Assessment of the risk to fish and fish habitat, specific to: 1. water quantity and timing of flows 2. sediment production and delivery, and 3. riparian function iii. HIGH, a Qualified Professional will complete a Detailed Risk Assessment of the risk to fish and fish habitat. b. For those relevant Key Watershed Residual Areas, assess and develop recommendations for the management of the Key Operational Factors 2. Primary forest activities will be carried out in a manner that is consistent with the results and recommendations of the assessments completed under sections 1.a.ii, 1.a.iii and 1.b of this strategy. FSP Strategy Definitions (to be included in FSP): Key Watersheds - Cottonwood River, Quesnel River (including Horsefly River and Cariboo River), Bonaparte River and Bridge Creek as identified in the Appendix I Maps Net Watershed Risk The combination of watershed risk at both the basin and sub-basin levels as outlined in Table 1 below. Table 1. Net Watershed Risk Rankings and Assessment Requirements Sub-basin Risk Peak Flow Hazard Net Risk Recommended Procedure Basin Low Low N/A Low Low N/A Low Low N/A Low Low Moderate N/A Moderate Moderate Low N/A Moderate Moderate Moderate N/A Moderate Moderate N/A Moderate Moderate N/A Moderate Low High Low or Moderate at Basin level Moderate Proceed with development planning Conduct Preliminary Risk Assessment. Proceed with development planning if risks are considered acceptable. Mitigation may or may not be required. Where High Risk Basin does not have a High Peak Flow Hazard, Conduct Preliminary Risk Assessment and proceed with development planning if risks are considered acceptable (with or without mitigation). Low High High at Basin level High Where High Risk Basin also has a High Peak Flow Hazard, Conduct Detailed Risk Assessment. Proceed with development planning if risks are considered acceptable. Mitigation is likely required, especially for high hazard elements. High Low Low or Moderate at Sub-basin level High Low High at Sub-basin level Moderate High Moderate High N/A High High Moderate N/A High High High N/A High High N/A High High N/A High Where High Risk Sub-basin does not have a High Peak Flow Hazard, Conduct Preliminary Risk Assessment and proceed with development planning if risks are considered acceptable (with or without mitigation). Where High Risk Sub-basin also has a High Peak Flow Hazard, Conduct Detailed Risk Assessment. Proceed with development planning if risks are considered acceptable. Mitigation is likely required, especially for high hazard elements. Conduct Detailed Risk Assessment. Proceed with development planning if risks are considered acceptable. Mitigation is likely required, especially for high hazard elements.

4 Key Watershed Reporting Units Basins and sub-basins within the Key Watersheds as identified in Appendix I Maps. Risk Rating Table -Results of a structured GIS-based ratings of key hazard indicators (stream flow, sediment and riparian function), fish values and risk to fish and fish habitat for Key Watershed Reporting Units, as updated from time to time. Key Watershed Residual Areas - areas within Key Watersheds that are not within Key Watershed Reporting Units as outlined in Appendix I Maps and to which Key Operational Factors still apply. Qualified Professional is an applied scientist or technologist specializing in a relevant applied science or technology including, but not necessarily limited to, agrology, forestry, biology, engineering, geomorphology, geology, hydrology or hydrogeology. An appropriately qualified professional must be registered in British Columbia with the appropriate professional organization, and acting under that association s Code of Ethics and subject to disciplinary action by that association. He or she must also be someone who, through demonstrated suitable education, experience, accreditation and knowledge relevant to the particular matter, may be reasonably relied on to provide advice within his or her area of expertise. Preliminary Risk Assessment A coarse filter office-based evaluation of current and future risks in a watershed involving review of Risk Rating Tables and maps, review of previous assessment reports and current aerial imagery. Assessment also includes the consideration of Key Operational Factors as well as Potential Downstream Impacts. Potential Downstream Impacts Potential impacts based on the significance of the proposed development, downstream fish values and associated risks. Detailed Risk Assessment A detailed assessment of watershed hazards and/or fish habitat and values completed by a Qualified Professional and may include a field based assessment component. Detailed assessment will build on information previously secured and assessed and will give specific consideration to stream flows (peak flows), sediment and riparian function in the assessment of watershed risk and development of mitigation and/or management recommendations. Key Operational Factors Considerations that should be made when proposing development within Key Watershed Residual Areas, include the following: Small Stream Management Assessment and consideration of development impacts on small streams not captured within Key Watershed Reporting Units, including the consideration of the significance of the stream, associated fish values, current riparian zone conditions and potential influence of development on the stream. Steep Coupled Slopes development on steeper slopes that are also connected to or close to streams have a greater potential to deliver sediment to streams. The GIS-model generating this indicator in the Risk Rating Table bases this assessment on steep slopes being those >50% and coupled slopes being those with <50m of gentle terrain between steep slopes and the stream. Gentle-Over-Steep Development Assessment of the increased hazards associated with harvesting and road building in Gentle-Over-Step (GoS) areas. GoS is defined as areas of relatively flat terrain (GIS-based Risk Rating Tables uses <50%) that are located above Steep Coupled Slopes (see definition above). These areas have an increased potential to delivery

5 sediment to streams, including larger erosion or mass wasting events on the adjacent Steep Coupled Slopes. Riparian Function Assessment and management of riparian function through reserve and management zones along the mainstem reaches within these areas, recognizing overall channel characteristics and active fluvial units (AFUs). Sediment Management Management of primary forest activities to ensure a low likelihood of sediment delivery to streams with significant fisheries values. The FSP strategy outlined above provides a methodical and defensible process that will be used to assess watershed risk and design and implement forest development accordingly. 5. Proposed FSP Strategy Salmon: The current FSP strategy will be revised to align with the changes made to the strategy for hydrologic stability. The changes are administrative in nature and are intended to make sure the two strategies align and do not overlap. The changes to the Salmon result/strategy can made available publically but are non-material in nature. 6. Operational Procedures: Operational Procedures were also developed to support the use of the GIS-based watershed risk ratings in timber development planning. The operational procedures represent the intent that is inherent within the FSP strategy. The operational procedures represent a stepped out approach on how watershed hazards and risk should be considered when primary forest activities are being planned within the project area.