Title: Assessment of the surface and groundwater interaction components of the Pitman rainfall-runoff model
Student: Jane Tanner
Country of origin: South Africa
University: Rhodes University
Degree:  MSc (Hydrology)
Supervisor: Prof. Denis Hughes
Year of registration: 2009
Student number: 609T7289

Groundwater and surface water are under constant interaction to each other in the hydrological cycle. For instance, over exploitation of groundwater can be reflected in decline of low flow in streams (Sami, 2004). Groundwater not only plays a significant role in sustaining baseflow of perennial rivers, but also in sustaining wetlands.

There is a recognized lack of quantitative information on the groundwater contribution to the flow regime in Africa. Estimation methods for groundwater and surface water flow regimes have developed separately from each other, although groundwater and surface water are intricately linked (Hughes, 2004). While the unique characteristics of surface and groundwater need to be recognized and understood, so too must their interaction and ability to enhance or detract from each other (Parsons, 2004). More than ever before, understanding the interaction between surface and groundwater is required to facilitate appropriate decision making and resource management.

The well known rainfall-runoff Pitman model has been modified to take account of groundwater. The model can be used to estimate the contribution of groundwater to baseflow and identify those areas in which groundwater plays an important role in sustaining baseflow, thus allowing for the optimisation of the allocation of human and financial resources for Reserve determinations. Tests have shown that the model can simulate interactions at quaternary catchment scales (Hughes et al, 2007). Despite revisions, model uncertainties remain and further investigation to improve the understanding of surface water and groundwater interactions will contribute to resolving these.

The MSc. will include:

• Developing conceptual hypotheses about the surface-groundwater interaction processes.
• Assessing the ability of the model to represent these processes.
• Investigating uncertainties associated with the surface-groundwater interaction component of the model.
• Developing guidelines for use of the model including statements of model limitations.

Last Modified: Tue, 18 Aug 2015 12:40:16 SAST