page # 1 eagles conference eagles conference december 3, 2002 case study 6: indicators of marsh...

PAGE # PAGE # 11 EaGLes ConferenceEaGLes ConferenceDecember 3, 2002December 3, 2002

CASE STUDY 6:INDICATORS OF MARSH

MAINTENANCE OF ELEVATION

comments byN. Scott Urquhart

Department of StatisticsColorado State University

Director of STARMAP

submitted byChuck Hopkinson

ACE INC


DISCLAIMERS

The work reported here todayThe work reported here today was developed was developed under the STAR Research Assistance Agreement under the STAR Research Assistance Agreement CR-829095 awarded by the U.S. Environmental CR-829095 awarded by the U.S. Environmental Protection Agency (EPA) to Colorado State Protection Agency (EPA) to Colorado State University. This presentation has not been University. This presentation has not been formally reviewed by EPA. The views expressed formally reviewed by EPA. The views expressed here are solely those of author and STARMAP, here are solely those of author and STARMAP, the program he represents. EPA does not the program he represents. EPA does not endorse any products or commercial services endorse any products or commercial services mentioned in this presentationmentioned in this presentation..

These comments are based on 1+ pages of textThese comments are based on 1+ pages of textexplaining the case study. I am confident I don’texplaining the case study. I am confident I don’tfully understand the situation!fully understand the situation!


THIS IS A “MEASUREMENT PROBLEM”

My discipline (statistics) seems to focus My discipline (statistics) seems to focus onon Data analysis, to the exclusionexclusion of Design of

Experiments, surveys, or responsesExperiments, surveys, or responses

Over the course of 40+ years ofOver the course of 40+ years ofcollaborations I rank the areas of mycollaborations I rank the areas of mycontributions as:contributions as:

Design of responses Design of studies Designing of analyses Interpretation of analyses


ON DESIGNING RESPONSES

A collaborative processA collaborative process I want to replicate part of that processI want to replicate part of that process

herehere Chuck Hopinson, the author of this caseChuck Hopinson, the author of this case

study, is aware I plan to “put him on study, is aware I plan to “put him on thethe

spot” today.spot” today. Why? Why?

I suggest the process of developing responsivemeasures is more important than the result

in any particular case.


STATED GOAL -- THE “CONCEPT” To develop a measure of marsh elevationTo develop a measure of marsh elevation

“health” based on an instantaneous“health” based on an instantaneous measure of the characteristics of measure of the characteristics of

marshmarsh tidal creek drainage networks tidal creek drainage networks

The intent is to extract the measure fromThe intent is to extract the measure fromdigitized representation of marshes.digitized representation of marshes.

Information providedInformation provided ...


FOLLOWING FIGURES ILLUSTRATE

Duplin River (from Wadsworth, 1980) Duplin River (from Wadsworth, 1980) illustrateillustrate The entire River watershed (5 images) Types of drainage networks (4 images) Individual networks

OverallOverall Few of 32 suchFew of 32 such

Rowley River marshes - false color aerial Rowley River marshes - false color aerial imagesimages Whole system (1 image) ID of subsystems (1 image) Images of subsystems (6 images)


STATED GOALcontinued

...... Information providedInformation provided

One+ page of text - available to you on the EaGLes web site

About 25 graphics What does Chuck think we should see in

these graphics?

Chuck?



Duplin River (from Wadsworth, 1980) Duplin River (from Wadsworth, 1980) illustrateillustrate The entire River watershed (5 images)


Figure 1


Figure 2


Figure 3


Figures 2 & 3 Beside Each Other


Figure 4


Figure 5



Duplin River (from Wadsworth, 1980) Duplin River (from Wadsworth, 1980) illustrateillustrate The entire River watershed (5 images) Types of drainage networks (4 images)


Duplin River

“Discrete Drainage”


“Dense Semidiscrete

”


“Sparse Semidiscrete”


“Reticulated”


Four Types of Drainage Networks:

Discrete, Dense Semidiscrete, Sparse

Semidiscrete, Reticulated




OverallOverall


NETWORK LOCATIONS


CHANNEL NETWORKS

Network Network #1#1





Rowley River marshes - false color aerial Rowley River marshes - false color aerial imagesimages Whole system (1 image)


IRPIETotalDR





Rowley River marshes - false color aerial Rowley River marshes - false color aerial imagesimages Whole system (1 image) ID of subsystems (1 image)


IRPIETotalDRwBoxtxt





Rowley River marshes - false color aerial Rowley River marshes - false color aerial imagesimages Whole system (1 image) ID of subsystems (1 image) Images of subsystems (6 images)


IRPIETotalDRNet1


IRPIETotalDRNet2


IRPIETotalDRNet3


IRPIETotalDRNet4


IRPIETotalDRNet5


IRPIETotalDRNet6


THE PROCESS OF DESIGNING RESPONSIVE MEASURES

PRINCIPLE 1: Concept under considerationPRINCIPLE 1: Concept under considerationshould be closely linked to the should be closely linked to the

measure:measure: If the concept changes, the measure should

change If the measures changes, the concept should

have changed.

Secondary considerationsSecondary considerations Efficient -- cost effective Accurate -- minimal bias Precise -- little variance among alternatives


THE PROCESS OF DESIGNING RESPONSIVE MEASURES II

PRINCIPLE 2: Think quite broadly about the PRINCIPLE 2: Think quite broadly about the limitations of a proposed measure tolimitations of a proposed measure tosharpen your framework.sharpen your framework.

Here, for example, think about coastal marshesadjacent to coastal mountains, like such as

are common along the West coast, from

southernCalifornia through Alaska, and onto islands.

Reflect on coastal marshes along the Gulf coast, as opposed to those located along the Atlantic How about the Bay of Fundy? Or Cook Inlet? Do you intend for the measure developed to apply

to only one type of system?


GOAL -- AN EVALUATION

To develop a measure of marsh elevationTo develop a measure of marsh elevation“health” based on an instantaneous“health” based on an instantaneousmeasure of the characteristics of measure of the characteristics of

marshmarshtidal creek drainage networkstidal creek drainage networks

without any calibration data, i.e. no field observations for ground truthingno field observations for ground truthing

I seriously doubt that such a measure I seriously doubt that such a measure can becan be

developed developed


WHY IS THIS GOAL IMPOSSIBLE?

Consider any particular marsh configurationConsider any particular marsh configurationobservable from an aerial photoobservable from an aerial photo

Suppose five years later the photo had exactlythe same configuration, but had

Moved 10m out into ocean from five years previousMoved 10m out into ocean from five years previous ===> Marsh “growing”

Moved 10m inland from location of five years previousMoved 10m inland from location of five years previous ===> March “shrinking”

Located exactly as five years agoLocated exactly as five years ago ===> March not changing

These cases are indistinguishable from only acurrent aerial photo


ON “HACK’S LAW”

“… “… most tidal creek drainages follow Hacks law, most tidal creek drainages follow Hacks law, which states that creek length varies to the 0.6 which states that creek length varies to the 0.6 power drainage basin area. (Torres) noted power drainage basin area. (Torres) noted substantial deviation from from Hacks Law for a substantial deviation from from Hacks Law for a substantial percentage of creek systems. The substantial percentage of creek systems. The deviation suggests that certain regions of the deviation suggests that certain regions of the marsh are not in equilibrium.”marsh are not in equilibrium.”

NSU: What is the natural variation away from NSU: What is the natural variation away from 0.6 across many systems in equilibrium?0.6 across many systems in equilibrium? Observed deviation may reflect nothing to be

explained! (0.6 power ?? Dimensional matters)


WHAT CAN WE DO?

REALITY: REALITY: The amount of land above The amount of land above waterwater

will depend on tidal stage (height), will depend on tidal stage (height), andand

perhaps on the stage of the tideperhaps on the stage of the tide Coming in, going out, how far inland, etc Perennial vs not; Constructed channel vs

natural Stream gradient immediately prior to its

entry into the marsh


A POSSIBLE APPROACH

Install a stage gauge (or several) in severalInstall a stage gauge (or several) in severalmarshesmarshes

Take remote (digital) images of each marshTake remote (digital) images of each marshseveral times, at diverse tidal stagesseveral times, at diverse tidal stages

Develop defensible classification forDevelop defensible classification for Water Not water

Evaluate area of each for fixed spatial Evaluate area of each for fixed spatial domaindomain

Build graph which follows for each marshBuild graph which follows for each marsh


EXPOSED “LAND” AS A FUNCTION OF TIDAL STAGE

0 2 4 6 8 10

TIDAL STAGE

EXPO

SED

LAN

D

}} Sediment Increase Sediment Increase

20052005

20252025


THANK YOU FOR YOUR ATTENTION

QUESTIONS and/or COMMENTS ARE WELCOME

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