School of Agricultural, Earth and Environmental Sciences

The Answers Lie in the Soil… and the Water

Ms Robyn Horan graduated with her Master of Science in Hydrology for research that used a climate derived water balance as an alternative to a complex soils routine within hydrological modelling – an important new method for areas where complex soils data are not freely available.

Horan’s research involved using climate data from the Cathedral Peak and Two Streams catchments to determine the amount of soil water the roots of vegetation had access to.

‘The modelling of soil water is extremely important as the soil determines the partitioning of water for the use by vegetation, to release as river flow and to percolate as groundwater,’ said Horan.

‘Where complex soils data is not accessible, hydrological modelling of soil water and catchments is challenging, however, climate data that includes rainfall, evaporation and river flow are more readily available.

This root zone storage concept was not widely researched, and Horan was inspired to attempt it under South African conditions. The concept was successful across different climate zones and vegetation, performing particularly well under forestry, closely reflecting the original published studies and better reflecting the observed soil water than traditional methods. This provided a more dynamic, robust and accurate conceptualisation of the soil water within the root-zone.

This could reduce the uncertainty in hydrological modelling in regions where soils and rooting characteristics are unknown, and assist in better estimation of forestry water use in South Africa, with significance for water resource management and water use policy and law.

The daughter of Hydrology lecturer Mr Mark Horan, Horan spent much of her childhood on campus, fascinated by the hydrology posters and catchment maps in the corridors of the Rabie Saunders Building, where her goal was to be a student. With an affinity for the natural environment, Horan began her academic career in engineering, before switching to the hydrology she so enjoyed.

Horan says her many valuable experiences as part of the UKZN Sports Executive, Chairperson of the UKZN Rowing and Tennis Clubs and a member of hockey, tennis, rowing and touch rugby teams, equipped her with essential life skills of leadership, resilience, team work, time management and determination.

‘UKZN provides so much more than education; by taking opportunities to get involved in different aspects of student life, UKZN can provide everything one needs to build all-round character, which is so vital in the workplace,’ she said.

After completing her Honours and looking for international experience, Horan submitted her CV to the UK Centre for Ecology and Hydrology (UKCEH) and was delighted to be offered a position as a water resources hydrologist, which she has held for the past two years while completing her masters part-time. She currently works with large-scale hydrological and land-surface models, focusing on the effect of humans on the hydrological cycle in India and Brazil.

Horan said doing her master’s developed her analytical skills, self-discipline and patience.

‘UKZN provided me with all I need to pursue an international career in Hydrology,’ said Horan. ‘Academically, I received a world-class education, practical experience and skills that are of a level not expected of a graduate internationally.’

Horan gave credit to her parents and her supervisor, Dr Michele Toucher, for their continuous support, and paid a special tribute to her father for the role he played throughout her life but especially during her time at UKZN.

Horan plans to start PhD studies after publishing some of her current research.

Words: Christine Cuénod

Photograph: Supplied