geog 409: advanced spatial analysis & modelling © j.m. piwowar1environmental modelling a...
TRANSCRIPT
![Page 1: Geog 409: Advanced Spatial Analysis & Modelling © J.M. Piwowar1Environmental Modelling A Drainage Basin Modelling Example Object: To determine the channel](https://reader035.vdocuments.net/reader035/viewer/2022062421/56649d085503460f949d9ad7/html5/thumbnails/1.jpg)
© J.M. Piwowar 1Geog 409: Advanced Spatial Analysis & Modelling Environmental Modelling
A Drainage Basin Modelling Example
Object: To determine the channel
discharge of a small drainage basin for a given rainfall.
![Page 2: Geog 409: Advanced Spatial Analysis & Modelling © J.M. Piwowar1Environmental Modelling A Drainage Basin Modelling Example Object: To determine the channel](https://reader035.vdocuments.net/reader035/viewer/2022062421/56649d085503460f949d9ad7/html5/thumbnails/2.jpg)
© J.M. Piwowar 2Geog 409: Advanced Spatial Analysis & Modelling Environmental Modelling
A Simple Hydrologic Model
Har
dis
ty, e
t al
. 1
993
. C
omp
ute
rise
d E
nvi
ron
men
tal M
od
elli
ng
: A
Pra
ctic
al I
ntr
od
uct
ion
Usi
ng E
xce
l. C
hic
he
ste
r: W
iley.
![Page 3: Geog 409: Advanced Spatial Analysis & Modelling © J.M. Piwowar1Environmental Modelling A Drainage Basin Modelling Example Object: To determine the channel](https://reader035.vdocuments.net/reader035/viewer/2022062421/56649d085503460f949d9ad7/html5/thumbnails/3.jpg)
© J.M. Piwowar 3Geog 409: Advanced Spatial Analysis & Modelling Environmental Modelling
Rainfall
Precipitation less evaporation losses. Assume rainfall falls evenly over the
basin. R = rainfall * surface area
Har
dis
ty, e
t al
. 1
993
. C
omp
ute
rise
d E
nvi
ron
men
tal M
od
elli
ng
: A
Pra
ctic
al I
ntr
od
uct
ion
Usi
ng E
xce
l. C
hic
he
ste
r: W
iley.
![Page 4: Geog 409: Advanced Spatial Analysis & Modelling © J.M. Piwowar1Environmental Modelling A Drainage Basin Modelling Example Object: To determine the channel](https://reader035.vdocuments.net/reader035/viewer/2022062421/56649d085503460f949d9ad7/html5/thumbnails/4.jpg)
© J.M. Piwowar 4Geog 409: Advanced Spatial Analysis & Modelling Environmental Modelling
Surface Storage
The amount of rainfall that is detained on the surface.
Assumptions: There is some pre-existing surface
storageOne-half of rainfall is retained in surface
storage. S = S + 0.5*R
Har
dis
ty, e
t al
. 1
993
. C
omp
ute
rise
d E
nvi
ron
men
tal M
od
elli
ng
: A
Pra
ctic
al I
ntr
od
uct
ion
Usi
ng E
xce
l. C
hic
he
ste
r: W
iley.
![Page 5: Geog 409: Advanced Spatial Analysis & Modelling © J.M. Piwowar1Environmental Modelling A Drainage Basin Modelling Example Object: To determine the channel](https://reader035.vdocuments.net/reader035/viewer/2022062421/56649d085503460f949d9ad7/html5/thumbnails/5.jpg)
© J.M. Piwowar 5Geog 409: Advanced Spatial Analysis & Modelling Environmental Modelling
Surface-Channel Discharge
The proportion of water in Surface Storage that immediately runs-off.
QSC = surface storage * constant1
Initial Assumption: constant1 = 0.9
Har
dis
ty, e
t al
. 1
993
. C
omp
ute
rise
d E
nvi
ron
men
tal M
od
elli
ng
: A
Pra
ctic
al I
ntr
od
uct
ion
Usi
ng E
xce
l. C
hic
he
ste
r: W
iley.
![Page 6: Geog 409: Advanced Spatial Analysis & Modelling © J.M. Piwowar1Environmental Modelling A Drainage Basin Modelling Example Object: To determine the channel](https://reader035.vdocuments.net/reader035/viewer/2022062421/56649d085503460f949d9ad7/html5/thumbnails/6.jpg)
© J.M. Piwowar 6Geog 409: Advanced Spatial Analysis & Modelling Environmental Modelling
Surface-Ground Discharge
The proportion of water in Surface Storage that percolates into the ground.
QSG = surface storage * constant2
Initial Assumption: constant2 = 0.6
Har
dis
ty, e
t al
. 1
993
. C
omp
ute
rise
d E
nvi
ron
men
tal M
od
elli
ng
: A
Pra
ctic
al I
ntr
od
uct
ion
Usi
ng E
xce
l. C
hic
he
ste
r: W
iley.
![Page 7: Geog 409: Advanced Spatial Analysis & Modelling © J.M. Piwowar1Environmental Modelling A Drainage Basin Modelling Example Object: To determine the channel](https://reader035.vdocuments.net/reader035/viewer/2022062421/56649d085503460f949d9ad7/html5/thumbnails/7.jpg)
© J.M. Piwowar 7Geog 409: Advanced Spatial Analysis & Modelling Environmental Modelling
Groundwater Storage
The amount of water in the unsaturated soil layers and in the saturated zone below the water table.
Assumptions: There is some pre-existing groundwater
storageOne-half of percolating rainfall is
retained in groundwater storage. G = G + 0.5*QSG
Har
dis
ty, e
t al
. 1
993
. C
omp
ute
rise
d E
nvi
ron
men
tal M
od
elli
ng
: A
Pra
ctic
al I
ntr
od
uct
ion
Usi
ng E
xce
l. C
hic
he
ste
r: W
iley.
![Page 8: Geog 409: Advanced Spatial Analysis & Modelling © J.M. Piwowar1Environmental Modelling A Drainage Basin Modelling Example Object: To determine the channel](https://reader035.vdocuments.net/reader035/viewer/2022062421/56649d085503460f949d9ad7/html5/thumbnails/8.jpg)
© J.M. Piwowar 8Geog 409: Advanced Spatial Analysis & Modelling Environmental Modelling
Ground-Channel Discharge
The proportion of water in Ground Storage that seeps back to the surface.
SGC = ground storage * constant3
Initial Assumption: constant3 = 0.3
Har
dis
ty, e
t al
. 1
993
. C
omp
ute
rise
d E
nvi
ron
men
tal M
od
elli
ng
: A
Pra
ctic
al I
ntr
od
uct
ion
Usi
ng E
xce
l. C
hic
he
ste
r: W
iley.
![Page 9: Geog 409: Advanced Spatial Analysis & Modelling © J.M. Piwowar1Environmental Modelling A Drainage Basin Modelling Example Object: To determine the channel](https://reader035.vdocuments.net/reader035/viewer/2022062421/56649d085503460f949d9ad7/html5/thumbnails/9.jpg)
© J.M. Piwowar 9Geog 409: Advanced Spatial Analysis & Modelling Environmental Modelling
Channel Discharge
The sum of the water run-offs from the surface and from the ground.
Har
dis
ty, e
t al
. 1
993
. C
omp
ute
rise
d E
nvi
ron
men
tal M
od
elli
ng
: A
Pra
ctic
al I
ntr
od
uct
ion
Usi
ng E
xce
l. C
hic
he
ste
r: W
iley.
![Page 10: Geog 409: Advanced Spatial Analysis & Modelling © J.M. Piwowar1Environmental Modelling A Drainage Basin Modelling Example Object: To determine the channel](https://reader035.vdocuments.net/reader035/viewer/2022062421/56649d085503460f949d9ad7/html5/thumbnails/10.jpg)
© J.M. Piwowar 10Geog 409: Advanced Spatial Analysis & Modelling Environmental Modelling Har
dis
ty, e
t al
. 1
993
. C
omp
ute
rise
d E
nvi
ron
men
tal M
od
elli
ng
: A
Pra
ctic
al I
ntr
od
uct
ion
Usi
ng E
xce
l. C
hic
he
ste
r: W
iley.
The “Catchwater” Drainage Basin