hydrological processes in the landscape simon lorentz honorary associate professor centre for water...
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HYDROLOGICAL PROCESSES IN THE LANDSCAPE
Simon Lorentz
Honorary Associate ProfessorCentre for Water Resources Research,
University of KwaZulu-Natal, Pietermaritzburg
WRC Khuluma Sizwe Series: Hydropedology in support of Hydrology and Eco-hydrology: 17 November 2014, Pretoria
CAN HILLSLOPE PROCESSES BE MODELLED AT CATCHMENT SCALE THROUGH HYDROPEDOLOGY MAPPING?
Better representation of hillslope water required for:
• Low flows • Land use changes
• Water quality• • Surface Water – Groundwater Interaction
8th IAHS Scientific Assembly and 37th IAH Congress: 6-11 September 2009, Hyderabad, India
Relationship between mean residence time of catchment discharge is best represented by the ratio of hillslope median flow path length and gradient
Catchment Soil response
(years)
Shallow response
(years)
Groundwater or baseflow response
(years)
Reference
River Fuegh, north Scotland 0.4 – 0.8 2 5 Rodgers et al., 2005Brugge, south Germany 2 - 3 5 - 20 Uhlenbrook et al.. 2002Zastler, south west Germany 2 - 3 6 - 9 Hoeg et al., 2000.Takanami, Japan 0 - 0.07 0.06 – 0.18 >1 Asano, et al., 2002Cascade Mtns, OR, USA 0.8 – 3.3 McGuire et al., 2005Weatherley, NECF, South Africa 0 - 0.01 0.3 Lorentz et al., 2003
109
4
321
8
6
5
7
RO14L
3/4R
3R
4RR
138A
14
15
121110R
Lower Catchment Area
123456
78
910A10 3/4
W1
W2
Upper Catchment Area
N
200m
Scale
LEGEND
CatchmentBoundary
Stream or Seep
Rock Outcrop
Additional g/w tube
Crump Wier
Lower catchmenttensiometer nestand piezometer
Full weather stationand fog interceptor
Transects
Neutron Probe Tube
8
3
Upper catchmenttensiometer nestand g/w tube
13
Rain gauge and foginterceptor
W2
Runoff plot
WEATHERLEY RESEARCH CATCHMENT: 1.5km2
HYDROMETRYGEOPHYSICSISOTOPESSOIL SURVEYET
WRC Khuluma Sizwe Series: Hydropedology in support of Hydrology and Eco-hydrology: 17 November 2014, Pretoria
ground surface
deeper perchedground water
temporary water inmacro pore zone
0.45m 0.30m
infiltration
macro pore flow
drainage
infiltration
tensiometers
less permeable horizon
-2500
-2000
-1500
-1000
-500
0
500
23-Jan-02 25-Jan-02 27-Jan-02 29-Jan-02 31-Jan-02
Mat
ric p
ress
ure
head
(m
m)
0
20
40
60
80
100
120
140
Cum
ulat
ive
rain
fall
(mm
)
200 500 800 Rain
NEAR SURFACE LATERAL FLOW
SOIL/BEDROCK INTERFACE LATERAL FLOW
Sustains low flows
WRC Khuluma Sizwe Series: Hydropedology in support of Hydrology and Eco-hydrology: 17 November 2014, Pretoria
HYDROMETRY
Weathered sandstone
Medium grain sandstone
Mudstone
LEGEND
Soil
ECT35070
Weathered sandstone
Medium grain sandstone
Mudstone
Initial water strike
High water table
Low water table
LEGEND
ECT35072
ECT35075
Soil
GEOPHYSICS
LC1-LC4
LC8-LC10
Lorentz et al., 2008
A
B
C
E
D
F
GH
I
J
ZONE 1
ZONE 3
ZONE 4
ZONE 5
ZONE 2
-30
-20
-10
0
10
20
30
40
-6 -4 -2 0 2 418O [o/oo V-SMOW]
2H
[o/ o
o V
-SM
OW
]
rain 2-3 Jan
rain 6-7 jan
surface water 7-8 Jan
hillslope groundwater 6-8 Jan
rain EM
surface water EM
hillslope groundwater EM
Hillslope groundwater response 64%
Rapid near surfaceresponse 36%
-30
-20
-10
0
10
20
-6 -4 -2 0
18O [o/oo V-SMOW]
2 H [o
/ oo V
-SM
OW
)
evaporated hillslope groundwater
hillslope groundwater
surface water
GMWL
ISOTOPES
Lorentz et al., 2008
Wenninger et al., 2008
NPS NUTRIENTS CONNECTIVITY
1989
1995
1999
2001
LOW FLOWS PREDICTION
0
5
10
15
20
25
30
Jan-01 Mar-01 May-01 Jul-01 Sep-01 Nov-01
Dis
ch
arg
e (
mm
/da
y)
ISSUES:
• LOW FLOWS• LAND USE CHANGE• WATER QUALITY• SURFACE WATER - GROUNDWATER INTERACTION• PREDICTION IN UNGAUGED BASINS
HYDROPEDOLOGY HYPOTHESES:
• WE CAN DEFINE TYPICAL HILLSLOPE DISCHARGE MECHANISMS• WE CAN MAP THESE TO PROVIDE INPUT TO CATCHMENT SCALE PREDICTIONS
WRC Khuluma Sizwe Series: Hydropedology in support of Hydrology and Eco-hydrology: 17 November 2014, Pretoria
THANK YOU
ACKNOWLEDGEMENTS:
• WATER RESEARCH COMMISSION• MONDI FORESTS• PG BISON• J. Pretorius
WRC Khuluma Sizwe Series: Hydropedology in support of Hydrology and Eco-hydrology: 17 November 2014, Pretoria