Basinwide Visual Estimation Technique BVET

2015

What is BVET?

• Stream habitat inventory method– Hankin and Reeves (1988)– Dolloff et al. (1993)

• A two-stage technique– visual estimates & measurements

• Products– calibrated estimate of stream area– inventory of habitat attributes

BVET Basics

PoolRiffle

•Visual estimates in every habitat unit

•Measurements at pre-determined intervals

BVET Habitat: 5 Steps1. Complete ‘header information’2. Select random number & measurement interval3. Walk upstream, stopping to record estimates at

upstream end of each habitat unit4. At randomly selected unit perform visual estimates,

then measurements (paired sample unit)5. Proceed upstream estimating in every unit and

measuring at pre-determined interval

• Repeat steps 4 and 5 until stream end is reached

Step 1: Header Information• Stream:

– Full stream name per USGS quad map

• District: – Forest Service District name

• Quad: – Name of USGS 1:24,000

quadrangle on which survey start point is located

• Date:– Record start date of survey

• Recorder & Observer: – Full names – no ab.– DO NOT change mid-survey

• Start GPS:– Map datum = NAD83

CONUS– Coordinate System =

UTM

• Start location: – Detailed written

description of starting point

• Notes: – Signs of human activity,

water condition, weather, hazards, etc.

Header Information on iPad

Step 2: Random Number & Interval

• Stream < 1.0 km– Measure every 5th unit– Random # 1-5– ex) random number = 3

• Paired sample at 3, 8, 13, 18, 23, etc.

• Stream > 1.0 km– Measure every 10th unit– Random # 1-10– ex) random number = 3

• Paired sample at 3, 13, 23, 33, 43, etc.

• Need a minimum of 3 fast water, 3 slow water pairs

• More paired samples = smaller confidence intervals

Step 3: Estimates for all units

1. Habitat Type & Number2. Distance3. Estimated Width4. Depth5. Substrate6. Percent Fines7. Large Wood8. Hemlock Large Wood

1. Five Habitat Unit Types

• Fast water– Turbulent

1. Riffle: <12% gradient2. Cascade: >12% gradient

– flat to convex bottom

– Non-Turbulent3. Run

– <12% gradient– flat bottom

• Slow water– Turbulent or Non-Turbulent

4. Pool– concave bottom

– Non-Turbulent5. Glide

– flat bottom

• Special situation– Underground: dry channel

Fast Water

•Riffle

•Run

•Cascade

Fast Water

Slow Water

• Pools

• Glides

Slow Water

Unit breaks - clear

Pool

Riffle

Riffle

Pool

Unit breaks - fuzzy

Glide

Riffle

Unit Number

• Group slow water: (pools & glides)• Group fast water: (riffles, runs, & cascades)

P1 G2 P3P4

G5

G6 P7

riffle riffle run cascade riffle riffle

R1 R5C4R2 RN3 R6

poolpool pool glideglide glidepool

Quick quiz:Random number is 5: Where are 1st fast water and slow water paired samples?

2. Distance

• Meters from start of survey to upstream end of unit– Measured with a hipchain

P1: 10.2

R1: 22.3

P2: 29.3

Hipchain

3. Estimated Width

• Average Wetted Width– Take entire unit into account

P1: 2.5

R1: 1.5

P2: 3.0

4. Depths

• Maximum Depth– Deepest point

• Average Depth– Average of several points

Riffle Crest Depth

• Measure at upstream end of FAST leading into SLOW; record in FAST data

Measuring crest depth

5. Substrate

• Dominant– Covers most surface area in unit

• Subdominant– Covers second most surface area in unit

• 9 size classes

Substrate Size Classes

1.Organic dead organics2.Clay sticky3.Silt slippery4.Sand silt- 2mm gritty5.Small Gravel 3-16mm sand to

fingernail6.Large Gravel 17-64mm fingernail to fist7.Cobble 65-256mm fist to head8.Boulder >256mm bigger than head9.Bedrock solid rock

How to measure substrate

A

BC

Substrate size classifications are based on the b-axis or

the second longest axis

A= longest axis

C= shortest axis

Quick quiz:Identify the three axis

positions

6. Percent Fines

• Percent of total area covered by sand, silt, or clay

7. Large Wood (LW)

• Dead, down, and within bankfull channel• >1.0 m long, >10 cm diameter• Four size classes

1. <5 m long, 10-55 cm diameter2. <5 m long, >55 cm diameter3. >5 m long, 10-55 cm diameter4. >5 m long, >55 cm diameter

Rootwad – count separately from attached LW

8. Hemlock Large Wood (LW)

• Identifiable as hemlock• Already counted in LW Data; this is a separate

count of only Hemlock• Dead, down, and within bankfull channel• >1.0 m long, >10 cm diameter• Combine all 4 size classes

LW quick quiz:

Congratulations!• You know what to estimate in every unit• What’s next??

Paired Samples

Step 4: Paired samples• Every paired pool

– Actual wetted width

• Every paired riffle1. Hemlock abundance

2. Hemlock condition

3. Measured Widths

a) Actual wetted width

b) Bankfull channel width (& Avg. bankfull depth)

c) Riparian width (left & right)

4. Gradient

5. Rosgen

6. Water temperature

7. Photo

1. Hemlock Abundance

• Estimate the total number of standing hemlocks (live or dead with DBH >10 cm) in the riparian zone (water’s edge to 30 m up the streambank; visually estimated) as you walk between paired sample units1. None = no hemlocks2. Few = 1-103. Some = 1-504. Many = >50 hemlocks

2. Hemlock Condition

• Estimate the condition of standing hemlock trees in the riparian zone as you walk between paired sample units1. Healthy/Light Infestation (0-25% needle loss)2. Infested (25-75% needle loss)3. Dead (>75% needle loss)

3a. Actual (measured) Width• Average wetted width

– Measure with a tape measure– Measure in at least three locations

3b&c. Bankfull Channel & Riparian Widths

• Bankfull channel width– bankfull to bankfull

• Riparian Width– 2-times maximum bankfull depth to landform

(flood depth)

3b&c. Channel and Riparian Widths

Bankfull Channel Width Right Riparian WidthLeft Riparian Width

2X Max Bankfull Depth

Riparian width measurement

4. Gradient

• Percent slope of the water surface– Measure with a clinometer– Riffles, runs, cascades

Be careful measuring gradient

5. Rosgen

6. Water Temperature

• Place thermometer in flowing water

• Out of direct sunlight if possible

• Record at measured riffles

BVET review

•Visual estimates in every habitat unit

•Measurements at pre-determined intervals

Stream Features

• Waterfalls, Dams, Roads, Trails, etc.

• Serve as landmarks– Record distance, GPS,

DETAILED description

• See features in manual for details

7. Photos• Face upstream• Use wading rod for scale• Get a wide angle• Take at paired fast water

units and features/crossings

BAD – can’t see channel

GOOD – can see channel

 S## Start locationP## Pause locationE## End locationT##b Tributary with name shown on quad mapW##b WaterfallB##b BridgeFd##b FordD##b DamV##b CulvertO##b Other ## = digits of stream IDb = use b, c, d, etc to create unique labels

when additional waypoints on thesame stream are needed

GPS Waypoint Labels

Ending the Survey

• Stop when you reach– Property boundary– Dry stream for > 500 m– Channel < 1.0 m wide for > 500 m

• Record– Time and date– Reason for stopping– GPS coordinates and written description– Be sure header info completed

• At home base– Back-up data – Record on master list/map that survey is complete– Download GPS