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1c. Determine Reach Potential 1b. Review Existing Information & Delineate & Stratify Reaches 1a. Identify Assessment Area & Assemble ID Team 1d. Complete PFC Assessment Integrated Riparian Management Process Steps 1a through 1d (7-step process)
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§Identify Assessment Area and assemble an ID team with: Strong observation and interpretation skills Knowledge of quantitative sampling that supports PFC Knowledge of hydrology, vegetation, and geomorphology attributes and processes. Knowledge of reference conditions Ability to communicate findings. Step 1: Assess Riparian Resource Function Using PFC
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Step 1: 1b. Review existing information: Riparian concepts The importance of uplands and tributaries Recovery process http://www.blm.gov/or/programs/nrst/tech_refs.php
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Step 1: 1b. Review Existing Documents Information specific to the drainage basin. Previous assessments, inventories, monitoring data. Resource information GIS data, etc.
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§1b. Delineate and stratify reaches: §Delineate the riparian areas into reaches/riparian complexes of similar character based on observable differences and/or similarities §May stratify reaches into groups with similar resource values, uses, geology etc. Step 1:
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Physiographic Processes and Attributes §Geology and Geomorphology §Topography – elevation, relief, aspect §Sediment source, transport, storage capacity Delineation:
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§Drainage area / Contributing area §Major confluences §Streamflow duration l Perennial, intermittent l Interrupted §Groundwater/surface-water interactions §Hydrologic regime l Snow-melt, storm runoff (monsoon), spring-fed brook Delineation: Hydrologic Processes and attributes
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Geologic filters Volcanic Limestone terrain Granitic terrain Basin fill Axial stream (perennial) Tributary stream (intermittent) Mountainous terrain Delineate Reaches 01020 Miles
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1c. Determining Potential of Stream Reaches Compare: 1) Hydrology, 2) Vegetation, and 3) Geomorphology Step 1:
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Why is potential important? §Accuracy - for the PFC assessment to be accurate. §Realistic - to gauge the system against what it can actually be.
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Potential Defined Potential is the highest ecological status a riparian area (stream reach or complex) can attain and is often referred to as the potential natural condition (PNC). Ecological status is the degree of similarity between existing conditions (hydrology, vegetation, and geomorphology) and the potential of a reach; the higher the ecological status, the closer the reach is to potential
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A site does not have to be at potential for a “yes;” it only has to be evaluated against its potential. Applying Potential to PFC PFC PNC Time NF FAR DC Unproductive Vulnerable Fisheries Values Livestock Values Recreation Values Wildlife Values Watershed Values Sustainable Ecological Threshold Decision Space
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Reference Reach Management Reach
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Consider (as an ID team): §Climate, landform, soil, hydrology, & vegetation relationships for clues l Regional and local riparian classifications & other literature l Historic information and photos l Species lists and habitat needs l Past inventory and monitoring data l Reference areas §Once stream potential is established, it should be documented! Process/tools for determining potential
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§ Numana Hatchery on Truckee River 6/1994
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§ Numana Hatchery on Truckee River 8/2013
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Factors that influence riparian plant species & communities: Wetness: Height above the water surface Substrate: Channel and bank particle size Slope: Stream gradient in percent Stream size: Channel width and depth Valley morphology: Geomorphic valley type
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Vegetation = sedge dominated banks and active floodplain with willows, cottonwood and aspen occurring on less frequently flooded surfaces E Type channel
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C4 type channel. Gravel-dominated substrate. Slope: < 2 % W/D: > 12 Sinuosity: > 1.4 Valley: broad/terraces
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B type channel; gradient > 2%; bedrock / boulder controlled; large wood important to channel complexity; vegetation = alder / fir
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Example Riparian Complex COMPLEX A Narrow Valley Bottom Steep gradient Coarse Substrate Alder/Dogwood COMPLEX B Wide Valley Bottom Low gradient Fine Substrate Tufted Hairgrass
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Riparian Complexes Groupings of potential plant communities that form vegetation patterns along the stream. From interaction of: hydrology, geomorphology and climate. Consider: Valley bottom gradient and width (types); Geology, deposition, and soil characteristics; Elevation; and climate.
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Delineation of Riparian Complexes §Valley bottom type (Rosgen 1996) §Dominant soil family (USDA, NRCS) §Entrenchment §Stream profile or gradient – Stream type (Rosgen 1996) §Vegetation patterns along the stream, §Land uses
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Valley Types Narrow, confined valley; Bedrock controlled Broad, unconfined valley; Alluvial fill
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Rosgen Valley Types X VIV VIII Gentle Canyon Wide Floodplain Glacial Trough Broad Lakebed
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From Rosgen 1996.
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Land Uses -- Management/land- ownership boundaries
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Capability – Old Concept Highest ecological status an area can attain given political, social, or economic constraints, which are often referred to as limiting factors. Limiting factors include railroads, dams, diversions, channelization, levees, roads, ground-water pumping, and related permanent alterations that change the potential of the reach.
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Applying Altered Potential to PFC §Change in TR revision is to “altered potential” instead of capability (for direct human alterations) §Capability simple to define but difficult to consistently apply §Capability precluded some altered streams from ever achieving PFC if gauged against historic potential or PNC
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Altered Potential… New Approach …Is the best possible ecological status and channel form that can be attained under permanent human alterations. Permanent human alterations include railroads, dams, diversions, channelization, levees, roads, ground-water pumping, and related permanent alterations that change the potential of the reach.
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§Are direct alterations (i.e. limiting factors) present that have created predominantly artificial channel conditions for a large part of the reach? If so, Don’t do PFC. Proposed Guidelines for Altered Systems
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§Are direct alterations present but the overall potential of the reach remains unchanged? Use potential. Proposed Guidelines for Altered Systems
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§Are direct alterations present but the overall potential of the reach has been changed (but is not predominantly artificial)? Describe new potential. Proposed Guidelines for Altered Systems Example: Diversion of > 50% of low flows has caused a drop in water table and potential has shifted from hydric to more mesic plant types.
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l Prediction – e.g. potential; response to management actions l Efficiency/Extrapolation – sampling a subset; applying throughout study unit l Prioritization – doing the right work in the right place with limited dollars and people Purpose of Delineation/Stratification:
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If you do not spend the time to develop an understanding of the attributes and processes affecting an area, your judgment about PFC will be incomplete and may be incorrect. Understanding Attributes and Processes - Determine Potential & Capability
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