School of Applied Sciences (SAS) (2006-July 2014)

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Browsing School of Applied Sciences (SAS) (2006-July 2014) by Supervisor "Allen, Peter M."

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    A complex systems approach to modelling environmental catastrophe
    (Cranfield University, 1994-08) Oxley, Tim; Allen, Peter M.
    In recognition of the widespread deterioration of the natural environment, and the continual emergence of sudden catastrophic environmental changes resulting from complex interactions of theretofore apparently disparate phenomena, this research presents a complex systems approach to the modelling of such environmental catastrophes. Recognizing contemporary views of complexity and evolution, this research presents a dynamic complex systems model which displays emergent characteristics which can be directly related to the modelled phenomena - linking acid rain and eutrophication - and the study region, the Rutland Water catchment. This is achieved through the definition of a catastrophe indicator which indicates both the proximity and magnitude of catastrophe arising from the non-linear and discontinuous acid-phosphorus relationship within the soil domain which lies at the heart of this Chemical Time Bomb phenomenon. This facilitates assessment of the vulnerability of the Rutland Water catchment to potential propagation of this CTB given continued acidification and phosphate accumulation. The main contributions of this research may thus be found in the following areas: Development of a dynamic complex systems model - transferable to alternative catchments due to the minimal data requirements and its generic representation - which may be used to describe non-point sources of phosphates as part of assessments of potential eutrophication, overcoming such limitations found in existing models. * Definition of a catastrophe indicator( Re)- which highlights both the proximity and magnitude of catastrophe describing a specific Chemical Time Bomb phenomenon whereby the soil suddenly changes from being a sink to a source of phosphates; long-term accumulations of phosphate in the soil being released as a consequence of soil acidification in the short-term. Presentation of a complex systems approach - hinged upon this concept of a catastrophe indicator - to the representation of non-linearities and discontinuities between heretofore apparently disparate phenomena which are 'competing for a common resource.
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    Integrated systems modelling of the interaction between water resources and agriculture
    (Cranfield University, 1999-10) Robinson, Allan; Allen, Peter M.
    Environmental problems associated with the use of water are inherently complex, involving the interaction of several different systems. Further, there is often limited data on the interaction, because of its location between disciplines. In order to study these problems in a quantitative, policy relevant way, a numerical model is required that integrates the different systems and is tailored to contain the processes important to the interaction. A numerical water resource system model is developed to study the problems associated with the interaction between agriculture and water. The model integrates an econometric model of farmer behaviour with a dynamic model of water flow and solute transport. The Argolid valley in Greece represents an area where severe environmental problems have arisen as a result of the overexploitation of groundwater for agriculture. When applied to the Argolid valley the water resource system model reproduces the evolution of the environmental problems that have arisen. It is then demonstrated that the model can be used to investigate some future scenarios and policy options related to the environmental problems that have developed. The main contribution of this research is to demonstrate that a properly designed numerical model that reproduces the dynamic interaction between human behaviour and the physical environment can enable the exploration of the evolution of environmental problems despite a lack of calibration data. Having achieved this the model can then be used in a policy relevant way to investigate the implications from a range of different, possible policy options.