School of Natural and Built Environment

Research over the past two decades on the Holocene sediments from the tide dominated west side of the lower Ganges delta has focussed on constraining the sedimentary environment through grain size distributions (GSD). GSD has traditionally been assessed through the use of probability density function (PDF) methods (e.g. log-normal, log skew-Laplace functions), but these approaches do not acknowledge the compositional nature of the data, which may compromise outcomes in lithofacies interpretations. The use of PDF approaches in GSD analysis poses a series of challenges for the development of lithofacies models, such as equifinal distribution coefficients and obscuring the empirical data variability. In this study a methodological framework for characterising GSD is presented through compositional data analysis (CODA) plus a multivariate statistical framework. This provides a statistically robust analysis of the fine tidal estuary sediments from the West Bengal Sundarbans, relative to alternative PDF approaches.

Research over the past two decades on the Holocene sediments from the tide dominated west side of the lower Ganges delta has focussed on constraining the sedimentary environment through grain size distributions (GSD). GSD has traditionally been assessed through the use of probability density function (PDF) methods (e.g. log-normal, log skew-Laplace functions), but these approaches do not acknowledge the compositional nature of the data, which may compromise outcomes in lithofacies interpretations. The use of PDF approaches in GSD analysis poses a series of challenges for the development of lithofacies models, such as equifinal distribution coefficients and obscuring the empirical data variability. In this study a methodological framework for characterising GSD is presented through compositional data analysis (CODA) plus a multivariate statistical framework. This provides a statistically robust analysis of the fine tidal estuary sediments from the West Bengal Sundarbans, relative to ...

Thermal groundwater is currently being exploited for district-scale heating in many locations world-wide. The chemical compositions of these thermal waters reflect the provenance and circulation patterns of the groundwater, which are controlled by recharge, rock type and geological structure. Exploring the provenance of these waters using multivariate statistical analysis (MSA) techniques increases our understanding of the hydrothermal circulation systems, and provides a reliable tool for assessing these resources.

Hydrochemical data from thermal springs situated in the Carboniferous Dublin Basin in east-central Ireland were explored using MSA, including hierarchical cluster analysis (HCA) and principal component analysis (PCA), to investigate the source aquifers of the thermal groundwaters. To take into account the compositional nature of the hydrochemical data, compositional data analysis (CoDa) techniques were used to process the data prior to the MSA.

The results of the MSA were examined alongside detailed time-lapse temperature measurements from several of the springs, and indicate the influence of three important hydrogeological processes on the hydrochemistry of the thermal waters: 1) salinity and increased water-rock interaction; 2) dissolution of carbonates; and 3) dissolution of sulfides, sulfates and oxides associated with mineral deposits. The use of MSA within the CoDa framework identified subtle temporal variations in the hydrochemistry of the thermal springs, which could not be identified with more traditional graphing methods, or with a standard statistical approach. The MSA was successful in distinguishing different geological settings and different annual behaviours within the group of springs. This study demonstrates the usefulness of the application of MSA within the CoDa framework in order to better understand the underlying controlling processes governing the hydrochemistry of a group of thermal springs in a low-enthalpy setting.

This paper is part of a special issue of Applied Geochemistry focusing on reliable applications of compositional multivariate statistical methods. This study outlines the application of compositional data analysis (CoDa) to calibration of geochemical data and multivariate statistical modelling of geochemistry and grain-size data from a set of Holocene sedimentary cores from the Ganges-Brahmaputra (G-B) delta. Over the last two decades, understanding near-continuous records of sedimentary sequences has required the use of core-scanning X-ray fluorescence (XRF) spectrometry, for both terrestrial and marine sedimentary sequences. Initial XRF data are generally unusable in ‘raw-format’, requiring data processing in order to remove instrument bias, as well as informed sequence interpretation. The applicability of these conventional calibration equations to core-scanning XRF data are further limited by the constraints posed by unknown measurement geometry and specimen homogeneity, as well as matrix effects. Log-ratio based calibration schemes have been developed and applied to clastic sedimentary sequences focusing mainly on energy dispersive-XRF (ED-XRF) core-scanning. This study has applied high resolution core-scanning XRF to Holocene sedimentary sequences from the tidal-dominated Indian Sundarbans, (Ganges-Brahmaputra delta plain). The Log-Ratio Calibration Equation (LRCE) was applied to a sub-set of core-scan and conventional ED-XRF data to quantify elemental composition. This provides a robust calibration scheme using reduced major axis regression of log-ratio transformed geochemical data. Through partial least squares (PLS) modelling of geochemical and grain-size data, it is possible to derive robust proxy information for the Sundarbans depositional environment. The application of these techniques to Holocene sedimentary data offers an improved methodological framework for unravelling Holocene sedimentation patterns.

The Sundarbans is one of the largest coastal wetland sites in the world and covers an area of approximately one million hectares of the western delta of the Ganges and Brahmaputra (G-B) rivers (located across Bangladesh and India). Since the late Holocene, the western delta has not been directly fluvially sourced, due to the Ganges shift to the east (present-day Bangladesh). The depositional facies (Thin Mud Facies) of the late-Holocene abandoned western region (The Sundarbans) is derived from dominant estuary-tidal dynamics, however the provenance of the associated TMF sedimentation in this far western zone (Indian Sundarbans per se) is as yet equivocal. In this study, sediment cores from the Indian Sundarbans (Saptamukhi-Thakuran estuary) were closely examined for grain-size distributions (GSDs), mineralogy through X-ray diffraction (XRD), and geochemistry with X-ray fluorescence (XRF). The TMF in the West Bengal Sundarbans has been determined to show intensively weathered, terrestrial sediment, derived principally from the Ganges Alluvial Plain (GAP). There is a predominance of quartz, mica and clay minerals, with quartz interpreted as a product of low-relief tropical weathering sourced via the G-B Rivers draining the Himalayas. Lithofacies interpreted through GSD analysis of the TMF is indicative of a muddy tidal flat environment with aggradation and a general fining-up trend between the adjacent estuaries. The sediment provenance indicates a continuing G-B sediment source, which moves westward along the Bay of Bengal, from the active delta front and is then reworked over the far-western abandoned delta by tidal–estuarine forcing.

The Sundarbans is one of the largest coastal wetland sites in the world and covers an area of approximately one million hectares of the western delta of the Ganges and Brahmaputra (G-B) rivers (located across Bangladesh and India). Since the late Holocene, the western delta has not been directly fluvially sourced, due to the Ganges shift to the east (present-day Bangladesh). The depositional facies (Thin Mud Facies) of the late-Holocene abandoned western region (The Sundarbans) is derived from dominant estuary-tidal dynamics, however the provenance of the associated TMF sedimentation in this far western zone (Indian Sundarbans per se) is as yet equivocal. In this study, sediment cores from the Indian Sundarbans (Saptamukhi-Thakuran estuary) were closely examined for grain-size distributions (GSDs), mineralogy through X-ray diffraction (XRD), and geochemistry with X-ray fluorescence (XRF). The TMF in the West Bengal Sundarbans has been determined to show intensively weathered , terrestrial sediment, derived principally from the Ganges Alluvial Plain (GAP). There is a predominance of quartz, mica and clay minerals, with quartz interpreted as a product of low-relief tropical weathering sourced via the G-B Rivers draining the Himalayas. Lithofacies interpreted through GSD analysis of the TMF is indicative of a muddy tidal flat environment with aggradation and a general fining-up trend between the adjacent estuaries. The sediment provenance indicates a continuing G-B sediment source, which moves westward along the Bay of Bengal, from the active delta front and is then reworked over the far-western abandoned delta by tidal–estuarine forcing.

Salama, A. M., & Sengputa, U. (Eds.) (2011). Affordable Housing: Quality and Lifestyle Theories. Open House International, 36(3), 1-132.

Affordable housing has long been an important planning and design concern in large urban areas and around the peripheries of major cities where population growth has led to an increasing demand for descent housing environments. The issue of affordability has attracted researchers and scholars to explore planning and design determinants, financing mechanisms, cultural and social issues, and construction and building techniques. This interest has been the case for several decades since affordable housing themes have offered a rich research area that involves many paradoxes that keep presenting challenges for planners, architects, and decision makers. Housing costs are increasing in most cities and incomes are not increasing at the same rate. Governments, on the other hand, are unable to provide sufficient housing stock to bridge the gap between demand and supply due to decreasing housing budgets and the lack of investment. Undoubtedly, the issue of housing affordability is widespread worldwide. Governments have responded to this issue through ways of cost reductions in order to make homes available at a price that a user is able to pay. However, this area of concern has been a permanent preoccupation of housing technocrats consumed in the quality and location of the housing unit, often overlooking other socio-cultural and psychological dimensions adhered to it. The academic community is no exception; it has responded to the issue of housing affordability by conducting research that places emphasis on the physical aspects of dwellings, while oversimplifying other critical demands placed on affordable housing provision by society and the environment.

Building on the earlier publications by the guest editors (Sengupta 2006; Salama, 2006; Salama and Alshuwaikhat, 2006; and Salama, 2007), this issue of open house international places high value on establishing links between issues that pertain to affordable housing, quality, and life style theories as manifested in socio-cultural factors, user preferences, and environmental attitudes. In essence, the papers selected for this edition address timely and pressing issues that continuously present themselves on the map of polemics on affordable housing both in developed and developing contexts, from Ecuador to Australia, from Turkey to Bangladesh and India, and from United Kingdom to Nigeria. Key issues of some of the papers presented in this issue are highlighted to reflect emerging understandings toward developing responsive affordable housing.

See Editorial: Salama, A. M. and Sengupta, U. (2011). Changing Paradigms in Affordable Housing, Quality, and Lifestyle Theories, Open House Internationa, 36, 3, pp4-6

The public sector has been a prominent actor in the urban housing sector in the State of West Bengal for the past three decades. Reform measures introduced since 1990 have led to a shift in the mode of public housing delivery from direct provision to providing housing in the market model. The concept of private-sector participation in construction and finance has emerged as a natural response to meet the colossal demand for housing within government's dwindling budgetary capacity and a need for a catalyst to boost macroeconomic conditions. Paradoxically, the public-sector agencies are leading the reform initiatives by assuming the role of a real estate developer. The paper reviews the housing output in Kolkata in the pre-and post-reform eras in terms of housing quantity, quality, price and affordability. It is argued that new reforms have been successful in stimulating the overall housing market, but more targeted programmes are needed to improve the supply, quality and affordability for low-income families in the city.

The paper is the outcome of a systematic effort to study and analyze the experiences of the Kirtipur Housing Project (KHP), the first ever grassroots-led squatter resettlement project in Kathmandu. It is widely hailed as a success story as it has been able to provide a legal, affordable and good quality housing solution to the Sukumbasis through grassroots mobilization. The paper analyses the dynamics of this mobilization and the roles of different actors to show how community empowerment, civil actions and local government interests have converged to create a constructive partnership in line with wider enabling principles. Apart from meeting the narrowly defined objective to rehouse 44 households, the project reflects capacity of the community, quite apart from lobbying and protest, in areas of project planning and management. While no grassroots mobilisation can be expected to replicate in a dynamic environment, the paper draws some policy insights that indicate the ability of the grassroots mobilization in Kathmandu to continue and grow. Conversely, the lessons learned from the project also point to limitations in terms lack of prerequisite critical mass or economic benefits to influence the government to prepare a policy framework under which it can foster in a more structured way.