1c. determine reach potential 1b. review existing information & delineate & stratify reaches...

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)

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

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

Step 1:

• 1b. Review Existing Documents• Information specific to the

drainage basin.• Previous assessments,

inventories, monitoring data.

• Resource information• GIS data, etc.

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:

Physiographic Processes and AttributesGeology and GeomorphologyTopography – elevation, relief, aspectSediment source, transport, storage capacity

Delineation:

Drainage area / Contributing areaMajor confluencesStreamflow duration

Perennial, intermittent Interrupted

Groundwater/surface-water interactionsHydrologic regime

Snow-melt, storm runoff (monsoon), spring-fed brook

Delineation: Hydrologic Processes and attributes

Geologic filters

VolcanicLimestone terrainGranitic terrain

Basin fill

Axial stream (perennial)Tributary stream (intermittent)

Mountainous terrain

Delineate Reaches

0 10 20

Miles

1c. Determining Potential of

Stream Reaches

Compare:1) Hydrology, 2) Vegetation, and 3) Geomorphology

Step 1:

Why is potential important?

Accuracy - for the PFC assessment to be accurate.

Realistic - to gauge the system against what it can actually be.

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

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

Tim

e

NF FAR

DC

Unproductive Vulnerable

Fisheries ValuesLivestock ValuesRecreation ValuesWildlife ValuesWatershed Values

Sustainable

Eco

logi

cal

Thr

esho

ld

Decision Space

Reference Reach

Management Reach

Consider (as an ID team):Climate, landform, soil, hydrology, & vegetation relationships for clues

Regional and local riparian classifications & other literature Historic information and photos Species lists and habitat needs Past inventory and monitoring data Reference areas

Once stream potential is established, it should be documented!

Process/tools for determining potential

Numana Hatchery on Truckee River 6/1994

Numana Hatchery on Truckee River 8/2013

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

Vegetation = sedge dominated banks and activefloodplain with willows, cottonwood and aspen occurring on less frequently flooded surfaces

E Type channel

C4 type channel. Gravel-dominated substrate.

Slope: < 2 %W/D: > 12Sinuosity: > 1.4Valley: broad/terraces

B type channel; gradient > 2%; bedrock / boulder controlled; large

wood important to channel complexity; vegetation = alder / fir

Example Riparian Complex

COMPLEX ANarrow Valley BottomSteep gradientCoarse SubstrateAlder/Dogwood

COMPLEX BWide Valley BottomLow gradientFine SubstrateTufted Hairgrass

Riparian ComplexesGroupings 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.

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

Valley Types

Narrow, confined valley; Bedrock controlled

Broad, unconfined valley;Alluvial fill

Rosgen Valley Types

X

VIV

VIII

Gentle Canyon

Wide Floodplain

Glacial Trough

Broad Lakebed

From Rosgen 1996.

Land Uses -- Management/land-ownership boundaries

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.

Applying Altered Potential to PFCChange 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

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.

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

Are direct alterations present but the overall potential of the reach remains unchanged? Use potential.

Proposed Guidelines for Altered Systems

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.

Prediction – e.g. potential; response to management actions

Efficiency/Extrapolation – sampling a subset; applying throughout study unit

Prioritization – doing the right work in the right place with limited dollars and people

Purpose of Delineation/Stratification:

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