Step 1: Assess Riparian Resource Function Using PFC

1d. Complete PFC assessment 17 questions about attributes and processes Reminder – PFC based on:

• Water (hydrology), • Vegetation, and • Soil & landform (erosion/deposition)

Checklist answers: Yes, No, or N/A (sometimes) Not “Liner” Notes for “No’s”, Many (all?) “Yes’s”, e g. species list

Item #1: Floodplain inundation

FloodplainLevel area near a stream channelConstructed by the streamIn the present climateFlooded during moderate & high flow eventsShould not be confused with terraces (abandoned floodplains)

(adapted from Leopold 1994)

Abandoned floodplain or terrace

Floodplain Channel

Hill slope

Valley flat

Floodplain – Geologic feature being formed by the river in its present condition and climate

Bankfull Concept InformationForest Service Stream Systems

Technology Center (Stream Team) website for on-line training videos, can order CDs and DVDs:

www.stream.fs.fed.us

1.Western U.S.

2.Northeastern U.S. (4 CDs)

3.Forested Streams Eastern U.S.

http://www.stream.fs.fed.us/publications/bankfull_west.html

Bankfull Indicators (Moody et al. 2003, Odem and Moody 1999)

Build a case based on physical evidence Series of depositional features at consistent

elevations with similar substrate and veg components Point bars at inside of meander bends, Point bars often not well developed with low sinuosity, Discontinuous alternating longitudinal bars parallel to

the channel often most dependable indicator Broad valley floors are almost always above bankfull

Field Observations

Floods Terrace

Bankfull

One year flow

Item 1: Floodplain inundated frequently1) Floodplain inundated in “relatively frequent

events” (1-3 years) Purpose: To determine whether frequent flood flows are

capable of spreading out on low-lying areas adjacent to the stream and thus provide for:

• energy dissipation• sediment deposition• periodic flooding of vegetation, and • periodic infiltration of flood water to replenish base flows

Bankfull

Floodplain

Item 1: Floodplain inundated frequently1) Floodplain inundated in “relatively frequent

events” (1-3 years) Flat, depositional surface adjacent to channel

• Low gradient, meandering (“C” and “E” channels)• Moderate gradient “B” channels

Indicators• Channel incision• Vertical banks on inside of bend & at straight reaches• Upland vegetation on streambank

Bankfull

Floodplain

BankfullBankfull

Floodplain

Terrace

Item 2: Beaver dams are stablePurpose: Beaver dams are hydrologic modifiers. Stable dams can increase stability by attenuating flood flows, providing a source for base flows, storing sediment, raising water tables and expanding riparian areas.

Unstable dams can reduce stability by causing channel incision, increasing bank erosion, lowering water tables and decreasing the extent of the riparian zone when they fail.

Indicators of beaver activity• Fresh workings on dams• Available building materials and food supply

Indicators of dams at risk• Single dams• No signs of maintenance and repair• Confined valleys - no floodplain• Large, flashy streams

Item 2: Beaver dams are stable

2: Beaver dams are stable

Examples of visual indicators Dam construction material Dams keyed into streambanks Breaches

Yes No NA

Item 3: Dimension, Pattern and Profile

3) Sinuosity, gradient, and width/depth ratio, are in balance with the landscape setting (i.e., landform, geology, and bioclimatic region)

Purpose: To determine if the pattern, dimension, and profile of the stream are within the expected range, given its landscape position, hydrologic regime, and natural sediment load.

Sinuosity, width/depth ratio, and gradient perform key roles in determining whether a stream can transmit water and sediment while managing erosive forces and remaining stable

Item 3: Dimension, Pattern and Profile

3) Sinuosity, gradient, and width/depth ratio, are in balance with the landscape setting (i.e., landform, geology, and bioclimatic region) Question has three parts

• Sinuosity• Width/Depth ratio• Gradient

All three must be "yes" for answer to be "yes" Must be appropriate for site

Sinuosity = Stream Length ÷ Valley Length1.9 = 370' ÷ 195'

Valley Gradient = 1.5%Stream Gradient = 0.8%

3) Sinuosity, gradient, and width/depth ratio, are in balance with the landscape setting (i.e., landform, geology, and bioclimatic region)

Examples of visual indicators Aerial photos

help with sinuosity

3.) Sinuosity, gradient, and width/depth ratio, are in balance with the landscape setting (i.e., landform, geology, and bioclimatic region)

4.) Riparian zone is expanding or has achieved potential extent.

Purpose: To document that a riparian area is recovering or has recovered.

Examples of visual indicators Riparian-wetland

community types expanded to valley edge

Stream narrowed Upland plants dying or

dead Depositions being

captured

4) Riparian area is expanding or has achieved potential extent

Yes No NA

Item 5: Riparian impairment from the upstream or upland watershed is absent.

5: Riparian impairment from the upstream or upland watershed is absent.

Trapping Cr BC 1996 Belgo Cr BC 1996

Yes No NAYes No NA

Degradation related to upstream or upland factors

Is there riparian degradation?

No riparian degradation observed.

Item 5 = “Yes”

Yes, riparian degradation observed

Degradation related to in situ activities

Item 5 = “Yes”

Item 5 = “No”

Yes

No

Purpose: To determine if riparian degradation is caused by a management within the riparian area or by environmental conditions or management outside the riparian area.