2014 69: Modelling drivers of tropical land-use change and their impact on local water resources

Co-Supervisor: Robert Ewers, Life Sciences

The Natural Environmental Research Council (NERC) is supporting 15 PhD studentships within a new Doctoral Training Partnership (DTP) focused on Science and Solutions for a Changing Planet. This brings together Imperial College London’s world leading expertise with that of our partners to offer a unique world-class multidisciplinary PhD training programme. The DTP will provide students with in-depth, advanced research training, as well as training in professional and transferable skills. Partners will offer training and secondment opportunities designed to enhance the students’ employability. Those partners with business and government experience will also provide skills coaching in policy, regulation, and entrepreneurship.

Tropical regions experience rapid land-use change. This is particularly the case for tropical forests, which are being cleared at a large scale to provide space for various agricultural and other activities. Inevitably, these changes have an impact on local and regional ecosystem services such as river flow regimes and water supply. At a local scale, the impact of forest clearance on surface water availability and quality depends on a complex interaction of physical processes, including changes in interception and evaporation from vegetation, and changes in hydrophysical soil properties and biogeochemical cycles, many of which are highly variable and poorly understood. At a regional scale, the impact of land-use change is determined by the spatiotemporal patterns of land-use and its interaction with water demand, e.g., for agricultural, domestic and industrial purposes.

Quantifying the impacts of large-scale land-use change on water resources in the tropics therefore requires bridging the local and regional scales, and evaluating the changes in local hydrological processes within a wider context of regional and global socio-economic change and its drivers.
This project will use the SAFE Project experimental site in Borneo as a case study to develop an integrated hydro-economic simulation system to assess and predict land-use change in the tropics and its impact on water-related ecosystem services.
In a first phase, this project will quantify the impact of logging and deforestation on surface water availability, focussing on how forest disturbance alters the physical processes of interception and evaporation from vegetation and hydrophysical soil properties. These data will be complemented with pre-existing stream-based hydrological and hydrometeorological data collected at the SAFE site to develop a physically-based model of tropical forest hydrology of unprecedented detail. This model will be calibrated on different land-use types present at SAFE (intact forest, logged forest and oil palm plantation), and predictions arising from the model will be directly validated via active deforestation that is happening at the site. Adequate uncertainty analysis frameworks available within the hydrology group will be applied.
In a next step, the physically-based hydrological model will be coupled to a socio-economic model to quantify the trade-offs between socio-economic use of a forest and water resources. We will work with Dr. Roman Carrusco (National University of Singapore) who is collecting fine-scale economic data on the income, costs and profits of logging and oil palm plantations in the same experimental river catchments we will work in. We will examine the impact of competing land use scenarios on water resources, such as logging at different intensities, converting different proportions of land cover to oil palm plantation, and varying the width of riparian set-asides. Our goal is to determine the spatial allocation of land use that will maximise the trade-off between revenue and water resources.