http://hdl.handle.net/2440/12 2013-05-25T14:18:03Z 2013-05-25T14:18:03Z Jorreto-Zaguirre, S. Dowd, Peter Alan Pardo-Igúzquiza, Eulogio Pulido-Bosch, A. Sánchez-Martos, F. http://hdl.handle.net/2440/77962 2013-05-24T03:30:06Z 2011-12-31T13:30:00Z

Title: Improved geostatistical simulation of the spatial heterogeneity of deltaic hydrofacies for environmental applications Author: Jorreto-Zaguirre, S.; Dowd, Peter Alan; Pardo-Igúzquiza, Eulogio; Pulido-Bosch, A.; Sánchez-Martos, F. Abstract: The spatial geological heterogeneity of an aquifer significantly affects groundwater storage, flow and the transport of solutes. In the particular case of coastal aquifers, spatial geological heterogeneity is also a major determining factor of the spatio-temporal patterns of water quality (salinity) due to seawater intrusion. The hydraulics of coastal hydrogeology can be modelled effectively by variable density flow equations but the aquifer geology is highly uncertain. A stochastic solution to the problem is to generate numerical models of the geology using sequential stratigraphy, geophysical models or geostatistical approaches. The geostatistical methods (two-point geostatistics, Markov chain models and multiple-point geostatistics) have the advantage of minimal data requirements, e.g., when the only data available are from cores from a few sparsely located boreholes. Advances in the geostatistical simulation of hydrofacies (categorical variables) have included more realistic models and more flexibility in variogram modelling. The variogram model used in the simulation of hydrofacies significantly influences the degree of connectivity of the hydrofacies in the simulated model. The choice of model is critical as connectivity determines the amount and extent of seawater intrusion and hence the environmental risk. The methodology is illustrated with a case study of the Andarax river delta, a coastal aquifer in south-eastern Spain. This is a semi-arid Mediterranean region in which the increasing use of, and demand for, groundwater is exacerbated by a transient tourist population that reaches its peak in the summer when the demand for the permanent population is at its highest. The work reported her contributes to the design of optimal management systems for groundwater resources.

2011-12-31T13:30:00Z Dowd, Peter Alan Pardo-Igúzquiza, Eulogio http://hdl.handle.net/2440/77961 2013-05-24T02:30:20Z 2011-12-31T13:30:00Z

Title: Geostatistical analysis of rainfall in the West African Sahel Author: Dowd, Peter Alan; Pardo-Igúzquiza, Eulogio Abstract: In this paper we attempt to resolve the controversy around interpretations of the changing rainfall patterns in the West African Sahel during the twentieth century. Some authors maintain that the data show clear evidence of drought starting in the 1970s and continuing through the 1980s (Dai et al., 2004), whilst other authors claim that the drought is an artefact of the decreasing number of rain gauges over the period in which the data were collected (Chapel and Agnew, 2004). It is somewhat surprising that none of the published studies on either side of this debate have used spatial methods, such as geostatistics, to model and interpret rainfall trends and to address data artefacts such as the decrease in the number of rain gauges. We report the results of a geostatistical study of rainfall patterns in the Sahel. We distinguish two sub-areas – the dry Sahel and the wet Sahel – and use block kriging with an anisotropic power semi-variogram to accommodate the latitudinal trend in rainfall. Our findings support the view that the period 1970-1989 was the most severe drought in the Sahel during the twentieth century and is not an artefact of the changing number of rain gauges and their locations.

2011-12-31T13:30:00Z Paton, Fiona Laura Gibbs, Matthew S. Maier, Holger R. Dandy, Graeme Clyde http://hdl.handle.net/2440/77954 2013-05-24T00:30:07Z 2011-12-31T13:30:00Z

Title: Impacts of climate change downscaling method on rainwater tank yield Author: Paton, Fiona Laura; Gibbs, Matthew S.; Maier, Holger R.; Dandy, Graeme Clyde Abstract: The impacts of climate change on rainwater tank yield are relatively unknown, with no studies analysing the effect of climate change downscaling method (CCDM), nor important rainwater tank parameters, on rainwater tank yield. This paper addresses these shortcomings by developing a general stochastic methodology to (1) study the impact of CCDM on rainwater tank yield and (2) understand the sensitivity of yield to important rainwater tank parameters under climate change scenarios. The methodology is applied to a case study of Adelaide, South Australia, whereby three CCDMs are compared for different tank sizes, roof sizes, demands, end uses and locations. Only small differences in rainwater tank yield between CCDMs were observed; however, at extreme percentiles the difference increased. These patterns were consistent across the important rainwater tank parameters, which when compared to the CCDMs, exhibited a much greater variability in rainwater tank yield. These findings suggest the climate change studies of rainwater tanks should include sensitivity analyses of important rainwater tank parameters and that more complex methods to account for climate change are only warranted should the study be concerned with extreme events.

2011-12-31T13:30:00Z Marchi, Angela Simpson, Angus Ross Do, Nhu Cuong http://hdl.handle.net/2440/77951 2013-05-23T06:30:13Z 2011-12-31T13:30:00Z

Title: Optimal scheduling of variable speed pumps in water distribution systems using genetic algorithms Author: Marchi, Angela; Simpson, Angus Ross; Do, Nhu Cuong

2011-12-31T13:30:00Z