201228 hobgen, sarah creating sediment budgets in resource and data poor environments

8/2/2019 201228 Hobgen, Sarah Creating Sediment Budgets in Resource and Data Poor Environments

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Creating Sediment Budgets in

data poor regionsThe case for combining radionuclide tracers

with Remote Sensing & GIS techniques

Sarah Hobgen

Research Institute for Environment and Livelihoods


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Why are sediment budgets important?

What is a sediment budget?

Creating a sediment budget

Radionuclide tracers

RS/GIS methods Summary

Overview of presentation


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Why are sediment budgets important?

Domestic water supply

Agricultural water supply

Hydroelectricity

generation


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What is a sediment budget?

Landslides GullyErosionRiver bank collapse/ Channel change

Rill & Sheet erosion

(Topsoil)

Storage in channel,

sediment bars

Sediment

discharged

Aims :

1. Determine relative importance ofdifferent erosion processes

2. Locate erosion sources

3. Quantify sediment volumes

4. Use simplified methods that require

minimal resources


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Creating a sediment budgetWhat are the

dominant erosionprocesses?

Radionuclide topsoiltracers

Manual imagery

analysis

Where in thecatchment is the

erosion occurring?

Topsoil Erosion RiskAssessment

Manual imagery

interpretation

Sedimentfingerprinting

How much sediment isreaching the weir or

river mouth?

RS & GIS

Field measurements

Generalisedequations

How are we going to use this information?

Determines the level of detail required

Resources available to complete the task


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Radionuclide Topsoil Tracers From nuclear weapons testing

Half life of 30 years

Useful for medium term erosion studies

Caesium - 137

Naturally occurring

Half life of 22 years

Medium term erosion studies

Lead - 210(excess)

From nuclear weapons testing

Long half life of 24,110 years

Medium term erosion studiesPlutonium - 239

Naturally occurring

Short half life of 53 days Short term or single flood event studies

Beryllium -7

Naturally occurring

Long half life of 1.5 million years

Estimating natural erosion ratesBeryllium 10


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Manual imageryinterpretation

Where in thecatchment is the

erosion occurring?

GIS Rapid TopsoilRisk Assessment

RS Manual imagery

interpretation

Sediment chemicalfingerprinting

How much sediment isreaching the weir or

river mouth?

RS & GIS

Field measurements





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RUSLE-based Rapid Topsoil Risk AssessmentFactor Methods Data Source Availability

R factor

Rainfall

Intensity

Monthly rainfall averages

interpreted to estimate

intensity using Fournier

equation

World Clim Global

climate model

Free to download

www.worldclim.org

LS factor

Slope length

Slope angle

LS module in many raster

GIS applications

ASTERv2 global DSM

SRTM DTM

Free to download

www.gdem.aster.er

sdac.or.jp

C factor

Land Cover

Supervised classification of

land cover classes

Landsat imagery,

30m resolution

Archive free to

download

glovis.usgs.gov

K factor

Soil erodibility

Determination of land units

from DEM

Field data collection at

representative locations

ASTER DEM -

Geology mapping

Field soil

classification

Field work or existing

soil mapping

required

P factor *

Land conserv.

practices

Manual identification on

high resolution imagery,

field mapping

Google Earth Free to use online

earth.google.com
http://www.worldclim.org/http://www.gdem.aster.ersdac.or.jp/http://www.gdem.aster.ersdac.or.jp/http://www.glovis.usgs.gov/http://www.glovis.usgs.gov/http://www.gdem.aster.ersdac.or.jp/http://www.gdem.aster.ersdac.or.jp/http://www.worldclim.org/


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RUSLE-based Rapid Topsoil Erosion Risk

Assessment

Kambaniru Catchment


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Connectivity of sediment sources to

the river


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Mapping gullies, landslides and

channel changeData Application Availability

Quickbird, SPOT

imagery

(High resolution)

Manual interpretation of

imagery to map gully,

landslide and channelmigration.

Accuracy assessments.

Google earth

Planet Action Initiative*

www.planet-action.org

Landsat Manual interpretation of

imagery to map gully,

landslide and channelmigration.

Archive free to

download

http://glovis.usgs.gov
http://www.planet-action.org/http://www.planet-action.org/http://www.planet-action.org/http://www.planet-action.org/


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RS & GIS

Where in the

catchment is theerosion occurring?

Rapid RiskAssessment

Manual imagery

interpretation Sediment

fingerprinting

How much sediment is

reaching the weir orriver mouth?

RS & GIS

Field measurements

Generalised

equations





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Quantifying sediment productionData Application Availability

Cartosat, LiDAR,Digital globe

DEM

Change detection for gully erosionand channel migration.

Quantifying sediment production

Purchase/order onlineLiDAR Cartosat websites

Aerial

photographs

(multiple imagedates)

Change detection

Sediment volumes can be estimated

using predictive equations

Dependent on location ,

project budget and security

requirements to accesshistorical imagery

Field

measurements

Estimating sediment volumes to

supplment aerial photo or imagery

analysis

Survey of weir and comparison with

blueprints

Require time and field

budget

Access to original plansand reports can be difficult

Generalised

equations

Estimate sediment yield using

results from RS and published results

Accuracy difficult to assess,

also does not capture

changes due to

management actions


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Sediment budget


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Sediment budgets are an important tool for landand water managers

Constant trade-off between accuracy andresources required

Radionuclide and spatial methods combined area powerful tool

Freely accessible data combined with opensource software provides an economical andefficient approach in data poor regions

Summary


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Acknowledgements

Research Award 2010

Postgraduate Research Award 2011-2013

Prime Ministers Australia Asia Award 2012

RESEARCH FUNDING:SUPERVISION:

Dr Bronwyn Myers

Research Institute for Environment and LivelihoodsCharles Darwin University

Prof Robert WassonDept. of Geography

National University of Singapore

Rohan FisherResearch Institute for Environment and Livelihoods

Charles Darwin University

Dr Guy BoggsAdjunct

Research Institute for Environment and Livelihoods

Charles Darwin University

201228 hobgen, sarah creating sediment budgets in resource and data poor environments

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