HYDROLOGICAL PROCESSES IN THE LANDSCAPE Simon Lorentz Honorary Associate Professor Centre 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

Better representation of hillslope water required for: Low flows 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

Groundwater or baseflow response 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 Groundwater or baseflow response Reference River Fuegh, north Scotland 0.4 – 0.8 2 5 Rodgers et al., 2005 Brugge, south Germany 2 - 3 5 - 20 Uhlenbrook et al.. 2002 Zastler, south west Germany 6 - 9 Hoeg et al., 2000. Takanami, Japan 0 - 0.07 0.06 – 0.18 >1 Asano, et al., 2002 Cascade Mtns, OR, USA 0.8 – 3.3 McGuire et al., 2005 Weatherley, NECF, South Africa 0 - 0.01 0.3 Lorentz et al., 2003

WEATHERLEY RESEARCH CATCHMENT: 1.5km2 10 9 4 3 2 1 8 6 5 7 RO1 4L 3/4R 3R 4RR 13 8A 14 15 12 11 10R Lower Catchment Area 10A 3/4 W1 W2 Upper N 200m Scale LEGEND Boundary Stream or Seep Rock Outcrop Additional g/w tube Crump Wier Lower catchment tensiometer nest and piezometer Full weather station and fog interceptor Transects Neutron Probe Tube Upper catchment and g/w tube Rain gauge and fog interceptor Runoff plot WEATHERLEY RESEARCH CATCHMENT: 1.5km2 HYDROMETRY GEOPHYSICS ISOTOPES SOIL SURVEY ET WRC Khuluma Sizwe Series: Hydropedology in support of Hydrology and Eco-hydrology: 17 November 2014, Pretoria

HYDROMETRY NEAR SURFACE LATERAL FLOW SOIL/BEDROCK INTERFACE Sustains low flows WRC Khuluma Sizwe Series: Hydropedology in support of Hydrology and Eco-hydrology: 17 November 2014, Pretoria

GEOPHYSICS LC1-LC4 LC8-LC10 Lorentz et al., 2008 ECT35070 LEGEND Soil Weathered sandstone Medium grain sandstone Mudstone LEGEND Soil ECT35070 LC1-LC4 Weathered sandstone Medium grain sandstone Mudstone Initial water strike High water table Low water table LEGEND ECT35072 ECT35075 Soil LC8-LC10 Lorentz et al., 2008

ISOTOPES Rapid near surface response 36% Hillslope groundwater B C E D F G H I J ZONE 1 ZONE 3 ZONE 4 ZONE 5 ZONE 2 Lorentz et al., 2008 Wenninger et al., 2008

NPS NUTRIENTS CONNECTIVITY

LOW FLOWS PREDICTION 1989 1995 1999 2001

SURFACE WATER - GROUNDWATER INTERACTION PREDICTION IN UNGAUGED BASINS 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 10

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 11