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Restoring and sustaining agricultural landscapes: <BR>Iinsights for ecosystem services and rural livelihoods (Communication session)

EUROSOIL2020CONT-2387

INVESTIGATING THE IMPACT OF RAINWATER HARVESTING IN SUBSISTENCE FARMING ON ECOSYSTEM SERVICES DELIVERY: A CASE STUDY OF THE SEMI-ARID MODDER RIVER BASIN IN SOUTH AFRICA

Johanna E. Schild^{* 1}, Jan E. Vermaat², Peter M. van Bodegom³, Maarten van ‘t Zelfde³, Yali Woyessa⁴, Worku Welderufael⁴, David Wiberg⁵

¹Soil Physics and Land Management Group, Wageningen University, Wageningen, Netherlands, ²Norwegian University of Life Sciences, Ås, Norway, ³Institute of Environmental Sciences CML, Leiden University, Leiden, Netherlands, ⁴Central University of Technology, Bloemfontein, South Africa, ⁵International Water Management Institute, Colombo, Sri Lanka

Content: Water shortages can seriously limit the capacity to provide ecosystem services in semi-arid regions, especially during dry periods. In these regions, land degradation processes combined with the impacts of climate change are expected to intensify water shortages. Therefore, opportunities need to be explored to increase the water holding capacity of the soil, for example by means of rainwater harvesting in farming.

In the semi-arid Modder river basin, located in the center of South Africa, in-field rainwater harvesting has been implemented on a small scale in subsistence farming. Upscaling of rainwater harvesting within the river basin could potentially improve soil water holding capacity and positively affect the delivery of ecosystem services.

This study aims to quantify the impact of the implementation of rainwater harvesting on the delivery of ecosystem services across the Modder river basin. The impact of rainwater harvesting implementation is assessed on the local scale for subsistence farmers as well as its downstream effects for urban users and commercial farmers.

The hydrological SWAT (Soil Water Assessment Tool) model is used to analyze the impact of rainwater harvesting on streamflow and water availability for agriculture in the Modder river basin. Different scenarios are investigated, ranging from the upscaling of rainwater harvesting in subsistence farming to largescale implementation of rainwater harvesting in commercial farming and rangelands. Temporal and spatial variation in the delivery of ecosystem services across the basin are explored.

Disclosure of Interest: None Declared

Keywords: Ecosystem services, Rainwater harvesting, Scenario Analysis, Semi-arid river basin, SWAT model