stream survey protocol comparisons; in search of truth, comparability and reality

Stream Survey Protocol Comparisons; In search of truth,

comparability and reality.

Brett Roper (broper@fs.fed.us)

Aquatic Monitoring Program Lead

USDA Forest Service

Overview

• Precision – this addresses how repeatable a given monitoring protocol is. The more repeatable the more confidence when have in any one observation (making a call at the stream reach).

• Are the results related to the “truth”.• Are there relationships among protocols – can data on

attributes be shared even if protocols are different. • If the question is of a high level indicator, say stream

health, are monitoring groups comparable?

Repeatability within a protocolRepeatability within a protocol

• Low coefficient of variationLow coefficient of variation

• High signal to noiseHigh signal to noise

• Discrimination among streamsDiscrimination among streams

Insures that different evaluations of a stream by a Insures that different evaluations of a stream by a monitoring program draws the same conclusion monitoring program draws the same conclusion regardless of who does the survey.regardless of who does the survey.

..

Lets look at the within group variability of gradient for the 12 streams

PIBO UpCol AREMP ODFW-S EMAP CFG

Mean 3.332583 3.73149 3.352407 3.481704 3.601553 3.40905

RMSE 0.237552 0.394455 0.198897 0.763588 0.492544 1.00649

CV 7.128166 10.57097 5.93971 21.91885 13.67588 29.52406

S:N 124.4179 49.23136 188.2179 14.08451 28.65087 4.87883

%Observer 0.007973 0.019908 0.005285 0.066293 0.033726 0.170102

%Stream 0.992027 0.980092 0.994715 0.933707 0.966274 0.829898

Groups 9 6 8 4 6 4

PIBO UC AREMP ODFWL EMAP CFG NIFC

Gradient A(1) A A(1) B A B  

BF Width A(1) B B D C B A 

WD C D B C D D  B(1) 

Sinuosity B B A(1)   B    

Entrenchment F F F(1) F F  F(1)  

% Pool D D B B D F  B(1)

Res Pool Depth A(1) A(1) A(1) A(1) A(1) D  A(1)

D50 B(1) C C   F  

Fines B(1) D B D C C

LWD # A(1) B A(1) B B  F  D

Most groups have repeatable protocols –A and B’s good for sites. B,C, and D’s good for large scale surveys that rely on large sample sizes or detecting large changes. F’s will be difficult to use in determining status or trend at a site or across sites.

If most protocols are OK (an no one can force them to change) the question becomes, are they related to each other and/or the ‘truth”

Some attributes appear to easily crosswalk, even if there is some variability within a

monitoring group

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T R U T HU CP IB OA R E M PO D F W SE M A PC F G

Truth to protocol; Gradient- All are good even if they were not of the

same repeatability.

Truth =0.05307+1.02799(AREMP) r2=0.995Truth =-0.30709+1.20253(CFG) r2=0.980Truth =-0.19464+1.04283(EMAP) r2=0.993Truth = 0.09352+0.9498(ODFWS) r2=0.963Truth =0.03793+1.05197(PIBO) r2=0.993Truth = -0.21219+1.00497(UC) r2=0.992

Sinuosity; By Stream

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P IB O

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Sinuosity – By stream type

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S tep P o o l P o o l R iffle P lan e B ed

A R E M P

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Truth to protocol; Sinuosity

Truth =0.10032+0.9172(AREMP) r2=0.93

Truth =0.18409+0.86456(EMAP) r2=0.95

Truth =0.31618+1.21918(PIBO) r2=0.76

Truth =0.40388+0.65961(UC) r2=0.87

Bankfull

PIBO UpCol AREMP ODFWS EMAP CFG NFIC

Mean 4.5653 4.0053 7.403117 6.164332 5.267525 6.097837 5.903125

RMSE 0.33124 0.5699 1.628248 2.575474 1.88915 1.484112 0.829206

CV 7.255621 14.229 21.99408 41.78026 35.8641 24.3384 14.04691

S:N 58.0629 20.22506 10.85588 2.808503 2.483763 6.774312 24.73901

%Obs 0.016931 0.047114 0.084346 0.26257 0.287046 0.128629 0.038852

%Stream 0.983069 0.952886 0.915654 0.73743 0.712954 0.871371 0.961148

Groups 6 4 3 4 3 4 4

Bankfull Width

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T ru thU CP IB OA R E M PO D F W SE M A PC F GN IF C

Truth to protocol; Bankfull.

Truth =-0.2986+1.2382(AREMP) r2=0.59Truth = 0.8448+1.1273(CFG) r2=0.63Truth = 0.6383+1.3139(EMAP) r2=0.73Truth = 1.8871+0.9654(NIFC) r2=0.57 Truth = 1.6484+0.9898(ODFWS) r2=0.65Truth = 1.6163+1.1731(PIBO) r2=0.59Truth = 2.1586+1.2536(UC) r2=0.52

Protocol to protocol; Bankfull pretty good across the board.

UC = 0.6621+0.4516(AREMP) r2=0.91

UC = 0.1320+0.6352(CFG) r2=0.95

UC = 0.1765+0.7939(EMAP) r2=0.95

UC = 0.4258+0.6158(NIFC) r2=0.98

UC = 0.6825+0.9898(ODFWS) r2=0.97

UC =-0.6227+1.0137(PIBO) r2=0.99

Width-to-Depth

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T ru thU CP IB OA R E M PO D F W SE M A PC F GN IF C

Truth UC PIBO AREMP ODFWS EMAP CFG NIFC

Truth 1 0.0320 0.334 0.006 0.336 0.121 0.003 0.32

UC 0.032 1 0.796 0.663 0.828 0.922 0.747 0.827

PIBO 0.334 0.796 1 0.519 0.743 0.694 0.503 0.731

AREMP 0.006 0.663 0.519 1 0.453 0.607 0.722 0.473

ODFWS 0.336 0.828 0.743 0.453 1 0.880 0.603 0.883

EMAP 0.121 0.922 0.694 0.607 0.880 1 0.789 0.906

CFG 0.003 0.747 0.503 0.722 0.603 0.789 1 0.716

NIFC 0.326 0.827 0.731 0.473 0.883 0.906 0.716 1

Sometimes protocol results may not be strongly related to the truth (this is difficult to say because truth had no data in streams with large values), but are still related to each other – Which is more important?

All the discussions up to now has focused on single attributes – but what about some higher level indicator called “stream health”

• If you add up the outcomes of several indicators do they give you the same picture across monitoring programs?

• How does standardizing results across several attributes affect signal-to-noise and conclusions about streams.

An example; using width/depth,% pools, residual pool depth, % fines and large wood count as indicators.

100*minmax

min)(

obs

Score

Standardize each of the attributes for each of the monitoring groups by applying the following equations;

100*minmax

min)(100

obsScore

% pool, residual pool depth, large wood count

width-to-depth, % fines

If you average these values

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A R E M P

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N IF C

O D F W S

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Then if you standardize to 1 to 100B

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S/N

4.59

0.69

2.76

11.35

1.84

2.49

5.32

Index Score – 1 = Best, 12 = Worst

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BF

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N IF C

UC PIBO AREMP ODFWS EMAP CFG NIFC

UC 1 0.636 0.723 0.432 0.613 0.716 0.603

PIBO 0.636 1 0.716 0.413 0.379 0.391 0.460

AREMP 0.723 0.716 1 0.396 0.549 0.716 0.549

ODFWS 0.432 0.413 0.396 1 0.459 0.603 0.878

EMAP 0.613 0.379 0.549 0.459 1 0.560 0.740

CFG 0.716 0.391 0.716 0.603 0.560 1 0.704

NIFC 0.603 0.460 0.549 0.878 0.740 0.7046 1

Relationship in the ranks of the index – all are significantly related (P<0.05) to each other but the strength of the relationship varies. This will need more work to relate to the ‘truth’.

So what did we learn from this protocol comparison

• Monitoring groups vary in repeatability for different attributes.• In most cases, monitoring group repeatability is at least acceptable and

correlated to what other groups are also measuring for that attribute.• Results from monitoring groups are related to some more strictly/

intensively defined “truth”.• The real Truth is defined by the monitoring objective; What are you

using Bankfull width for? It appears this question is sometimes forgotten in the search for repeatability.

• If the real question is some higher level indicator like “stream health”, data from different groups seem to be correlated.

• If the stream population from which the sample came from can be defined, then it may be possible to use monitoring group as a block effect when analyzing trend (when repeatability is acceptable) – status may be more difficult because each protocol measures a slightly different mental construct of and attribute.