On the channel head location using DEM

Channel head locationChannel head locationusing DEMsusing DEMs

Meeting in Bari • 22-24 September ’09

Autorità di Bacino della PugliaLR 9 dicembre 2002c/o InnovaPuglia S.p.A.www.adb.puglia.it

Politecnico di BariDipartimento di Ingegneria delle Acquee di Chimicawww.diac.poliba.it

CHANNEL HEADS

EXTENTOF CHANNEL NETWORK

Geomorphic &

HydrologicAnalyses

EnvironmentalManagement

CHANNEL NETWORK OF APULIA REGION

Estimating channel head location according scientific basis

KEY ASSUMPTIONS

LandscapeGeomorphologic form

Erosionprocesses

DYNAMIC EQUILIBRIUMbetween

SOIL PROPERTY&

CLIMATE REGIME

Channel network rapresents indeed the mark on landscapeof intermittent discharge series of flow and sediment transport


KEY ASSUMPTIONS

LandscapeGeomorphologic form

Erosionprocesses

DEM analysis

Dominant sediment and transport

process

+Geomorphologic thresholds

GEOMORPHOLOGICTHRESHOLDS

= ƒ ( A, S)

Drainage Area

Surface slope

Drivers of erosion processesBut also

Indicators of past erosive actions


PILOT CATCHMENT

UTM CoordinateE = 593735,06 N = 4638391,50

A = 27 SKm

BasA

EASTERN GARGANO

0.300

0.400

0.500

0.600

0.700

0.800

0.900

1.000

0.00000 0.20000 0.40000 0.60000 0.80000 1.00000

Ai / A

h i

/ h m

ax

h media

Absance of tectonic forces

Soil impermeability

MATURESTAGE

DTM 5 x 5 m

Fill Dem

Slope

Flow Directions

Flow accumulation

Energy Index

TWI

TURNOVER

40 pixel=

1100 mq

0>dAdS

0<dAdS

0.010

0.100

1.000

1 10 100 1000 10000 100000

Drainage Area [pixel]

Lo

ca

l S

lop

e [

m/m

]

n

SLOPE-AREA PLOT AvsP

[Gilbert] slope-dependent sediment transport gives rise toCONVEX PROFILE

Discharge and slope dependent sediment transport gives rise to CONCAVE PROFILES

Transition from CONVEX

to CONCAVE

profiles

=Transizione

HILLSLOPE - VALLEY

NO!! Channel Head

AvsP

TURNOVER

40 pixel=

1100 mq

0>dAdS

0<dAdS

AvsP

TURNOVER

40 pixel=

1100 mq

0>dAdS

0<dAdS

Transition from CONVEX

to CONCAVE

profiles

=Transition

HILLSLOPE - VALLEY

NO!! Channel Head

0,010

0,100

1,000

1 10 100 1000 10000 100000

Area drenata [pixel]

Pe

nd

en

za lo

ca

le [

m/m

]

0,010

0,100

1,000

1 10 100 1000 10000 100000


Pe

nd

en

za lo

ca

le [

m/m

]

SA1

0,010

0,100

1,000

1 10 100 1000 10000 100000


Pe

nd

en

za lo

ca

le [

m/m

]

SA1

y = 1,2354x-0,3257 R2 = 0,3192

0.010

0.100

1.000

1 10 100 1000 10000 100000


Pen

den

za l

oca

le [

m/m

]

potenza1

SA1 SA2

y = 1,2354x-0,3257 R2 = 0,3192

0.010

0.100

1.000

1 10 100 1000 10000 100000


Pen

den

za

local

e [m

/m]

potenza1

SA1 SA2 SA3

SA1 = 40 pixel

SA2 = 200 pixel

SA3 = 1100 pixel

AvsP

CUMULATIVE AREA DISTRIBUTION PLOT

0,001

0,01

0,1

1

1 10 100 1000 10000 100000

A* [pixel]

P(A

>A

*)

SA1 = 40 pixel CAD1

0,001

0,01

0,1

1

1 10 100 1000 10000 100000

A* [pixel]

P(A

>A

*)

CAD1

y = 11,685x-1,2068 R2 = 0,9994

0,001

0,01

0,1

1

1 10 100 1000 10000 100000

A* [pixel]

P(A

>A

*)

potenza1

CAD1

SA3 = 1100 pixel CAD2

0,001

0,01

0,1

1

1 10 100 1000 10000 100000

A* [pixel]

P(A

>A

*)

CAD1 CAD2

y = 0,5267x-0,4825 R2 = 0,9969

0,001

0,01

0,1

1

1 10 100 1000 10000 100000

A* [pixel]

P(A

>A

*)

potenza2

CAD1 CAD2

≅ -0,43 fluvial channel

CAD

ENERGY INDEX DISTRIBUTION PLOT

0,0001

0,001

0,01

0,1

1

1,000 10,000 100,000

Energy Index EI*

P(E

I>E

I*)

ASEI ⋅=

0,0001

0,001

0,01

0,1

1

1,000 10,000 100,000

Energy Index EI*

P(E

I>E

I*)

EID10,0001

0,001

0,01

0,1

1

1,000 10,000 100,000

Energy Index EI*

P(E

I>E

I*)

EID1 EID2

Slope-dependent crtical contributing area

EID

2)(tanϑC

Acr =

EID

25.0 24

=⇒=⋅=S

AASEI2

5.0 1020

=⇒=⋅=S

AASEI

EID1 EID2

ENERGY INDEX DISTRIBUTION PLOT

0,0001

0,001

0,01

0,1

1

1,000 10,000 100,000

Energy Index EI*

P(E

I>E

I*)

EID1 EID2

Slope-dependent crtical contributing area

AvsPCADEID

0,01

0,1

1

1 10 100 1000 10000 100000


Pe

nd

en

za lo

ca

le [

m/m

]

0,01

0,1

1

1 10 100 1000 10000 100000


Pe

nd

en

za lo

ca

le [

m/m

]

SG1 SG20,01

0,1

1

1 10 100 1000 10000 100000


Pe

nd

en

za lo

ca

le [

m/m

]

SG1 SG2 EID1

EID2

VERSANTI.basA: if(($tca.basA$<40),5,null)VALLI.basA: if(($tca.basA$>=40)&&($EI.basA$<4),4,null)HEAD.basA: if(($EI.basA$>=4)&&($ tca.basA$<1100),3,null)RETICOLO.basA: if($tca.basA$<1100,null,2)

y = 151,08e-0,9204x

R2 = 0,9473

y = 19,069e0,4895x

R2 = 0,9855

y = 351,38e1,4369x

R2 = 0,9741

1

10

100

1.000

10.000

100.000

1.000.000

1 2 3 4

u

Nu

,Lu

*,A

u

u vs. Nu u vs. Lu* u vs. Au

1 ̂legge di Horton 2 ̂legge di Horton legge di Schumm

0

5

10

15

20

25

0 0,5 1 1,5 2 2,5 3

t [h]

Q [

mc

/s]

RA

RB

RL

LGIUH

• Abrahms A.D.; Channel networks: A geomorphological perspective; Water Resources Research, 25, 29-49; 1984• Flint J.J.; Stream gradient as a function of order, magnitude and discharge; Water Resource Research, 10 (5), 969-973; 1974 • Gilbert G.K.; The convexity of hill tops; Journal of Geology, 17, 344-350; 1909• Kirkby M.J.; Hillslope process-response models based on the continuity equation; Institute of British Geographers, Special Publication, 3, 15-30; 1971• Kirkby M.J.; The stream head as a significant geomorphic threshold; Thresholds in Geomorphology, Allen & Unwin, 53-73; 1980• McNamara J.P., Ziegler A.D., Wood S.H., Vogler J.B.: Channel head locations with respect to geomorphologic thresholds derived from a digital elevation model: A casa study in northern Thailand; Forest Ecology and Management, 224, 147-156; 2006• Montgomery D.R., Dietrich W.E.; Source areas, drainage density and channel initiation; Water Resource Research, 25, 1907-1918; 1989• Montgomery D.R., Foufoula-Georgiou E.; Channel network source representation using digital elevation models; Water Resources Research, 29, 12, 3925-3934; 1993• Rodriguez-Iturbe I., Rinaldo A., Rigon R., Bras R.L., Marani A., Ijjasz-Vasquez E.; Energy dissipation, runoff, and the three-dimensional structure of river basins; Water Resources Research, 28 (4), 1095-1103; 1992a

Bari, 24/09/2009