Session 7 - Implication of Urbanisation on Building Material induced Land use, Soil, Water and Waste in Urban Regions

Convener - Georg Schiller, Stefan Bringezu

Speaker Titel Abstract Kind of presentation
Andreas Blum, Robin Gutting Demographic Change and Housing – Case Study Research on Implications for Building Material Consumption  Housing and construction have a significant impact on the consumption of resources of any society. At the same time, on all policy levels strategy documents towards sustainable development highlight the importance of improvements in resource efficiency. Against this background, this contribution presents results of research on the impact of demographic trends and changing user preferences on the use of resources within the housing sector with a focus on construction materials. The material intensity of different types of housing (in particular detached homes vs. apartment buildings) are quantified under different development scenarios drawn on the basis of two medium sized German case study municipalities showing declining and stagnating population development. Among other, the results indicate that the stock of construction materials incorporated within the housing sector will under trend conditions further increase despite a stable or even falling population. With respect to alternative development scenarios, our results show, that under the condition of a stable or growing population a shift of housing supply from single-family (detached) homes towards a higher share of multi-unit residential buildings can contribute to a more efficient use of materials (stock of construction materials per capita). However, depending on the development context such a development might as well be accompanied by higher vacancy in single family homes with the result of the respective embodied materials being wasted. An interesting option under the condition of a declining population is the conversion of a potentially growing number of vacant single-family homes into smaller multi-unit/multi-purpose residential buildings since it can help to avoid vacancy and keep otherwise wasted resources in use. Oral (normal length)
Laura Johanna Tams, Thomas Nehls Rethinking green roofs - Potential of natural and recycled green roof materials to improve their ecological footprint  Nature-based-solutions are discussed to regulate urban waters, to increase biodiversity or to sustainably regulate urban climate, to mitigate urban heat islands and thus to counteract urban heat stress. As such, green roofs are extremely important especially for South Europe. The discussion of green infrastructures focused mainly on their ecosystem services while the ecological burdens of their construction, use and demolition have not been considered with the same weight. The majority of the CO2 emissions are due to production of synthetic liners, drainage layers and planting substrates cause that the green roof construction cannot be amortized during their expected lifetime of 45 years. Therefore, in this study we investigated the potential of - recycled urban wastes instead of mined substrates to be used as plant growing substrates, and - alternative natural or recycled materials for green roof drainage layer and liners to improve green roof's ecological footprints in terms of CO2 emissions, water consumption and land conversion. We assed the use of different alternatives to planting substrates such as crushed bricks and compost instead of expanded clay and peat and cork board as an alternative for the conventional sealing layer materials. Cork board, made out of cork granules, is a byproduct in the cork industry or could be produced from recycled cork and is expected to have a smaller ecological footprint than the conventionally used synthetic, mineral-oil based materials. To assess the influence of the different construction materials on the CO2 emissions, water consumption, land conversion etc. of green roofs, a comparative LCA was conducted. Based on that we also calculated CO2 amortization time spans and compared them to ecosystem services during the green roof's expected lifetime. Oral (normal length)
Susanne Kytzia Implication of urban development on building material induced land use  In Switzerland, mineral building materials like concrete, gravel and sand, are locally available in most regions. Their production occupies land and conflicts with landscape development, agriculture and forestry. In densely populated areas in the Swiss lowlands, finding new sites for gravel extraction proves to be a challenge. Construction activities create construction waste and excavated materials that must be landfilled. With increasing land scarcity, recycling of excavated materials with high gravel content and waste concrete tend to increase. This transition towards a circular economy for building materials however must consider transport costs, from both an environmental and economic perspective. Since these materials are mass flows with low economic value, spatial distribution of sites for construction, demolition, extraction, deposition determine the local transport network. These distribution patterns vary with alternative strategies of urban development and form important boundary conditions. This paper presents a system dynamic model of land-use development to understand effects of urban development policies. These policies create framework conditions to produce gravel and sand and drive local demolition waste and excavated material management. It is applied to evaluate the effects of alternative strategies of urban development in Switzerland. The model builds on material flow data and integrates dominant policies of key stakeholders, derived from case studies of companies in the construction material industry and a group model building process involving relevant stakeholders. Results show, that available capacities for extraction and disposal of resources are very important parameters on a regional scale. Developing a circular economy for construction materials must consider the dynamic development of mass flows, such as gravel and excavated materials and mineral construction waste. Urban development aiming at densification and brown-field development favours recycling of construction waste whereas green-field development at the settlement borders encourages use of virgin gravel or excavated materials with high gravel content. Oral (normal length)
Georg Schiller Regional construction material flows due to urbanization - the case study Hanoi and hinterland  Urbanization is a global trend. This is particularly true for Southeast Asia. In Vietnam, for example, the per capita consumption of mineral construction materials in 2010 was already 80% over the level in Germany, although the degree of urbanization was only around 30%, compared with almost 75% in Germany. With increasing urbanization rate and prosperity, also the demand for construction materials is growing. This is a major challenge for the hinterland provinces of the urban areas, as they are essentially responsible for supplying the cities with construction materials. Since bulk non-metallic construction minerals are characterized by short transport distances they manifest physical links between urban areas and their rural surroundings, where mining and dumping activities cause land use changes. Although urbanization and land-use change are two global, closely related phenomena, their analytical frameworks and the relevant literature were largely developed separately so far. The contribution discusses elements of a conceptual approach of regional material flow analysis (MFA) for pointing out construction material flows between urban and rural, using the case study area of Hanoi and Hoa Binh Province as an example. Based on this, a quantification to what extent material substitutions can contribute to a more resource-efficient urbanization was carried out. The results show that the demand for construction minerals will continuously increase in the case study area. For sand and clay the demand cannot be covered by the surrounding hinterland. On the other hand, it is shown that the demand for raw construction materials can be significantly reduced by consistently exploiting material substitution potentials. However, it is important to recognise that this can lead to shifts between different types of raw materials. Finally the study emphasizes the urgent need for holistic transdisciplinary concepts of resource management and land-use planning in order to bridge the urban - rural dichotomy. Lightning talk in the session and a poster
RAWAL SINGH AULAKH, AMANPREET KAUR Built Heritage and Sustainability: Devising the Evaluation Criteria for Built Heritage for Indian Medieval Cities  Preserving historic buildings is vital to understanding our nation's heritage. Heritage building conservation and sustainable development, in general, are considered to be natural allies. In addition, it is an environmentally responsible practice. By reusing existing buildings historic preservation is essentially a recycling program of 'historic' proportions. Existing buildings can often be energy efficient through their use of good ventilation, durable materials, and spatial relationships. An immediate advantage of older buildings is that a building already exists; therefore energy is not necessary to demolish a building or create new building materials and the infrastructure may already be in place. Minor modifications can be made to adapt existing buildings to compatible new uses. Systems can be upgraded to meet modern building requirements and codes. This not only makes good economic sense but preserves our legacy and is an inherently sustainable practice and an intrinsic component of whole building design ( 2017). The sensitivity towards preservation of Heritage building in India is not, probably, compared to that of the western world. This may be primarily due to the reason that before preservation or restoration of the heritage buildings much more facilities of basic needs of the residents is thought to be important, in lieu of which the state of heritage buildings is negated to quiet an extent. Further, the intervention and imitation of strategies of conservation, refurbishment, reuse, and redevelopment are borrowed blindly from Western cases/ projects. The concepts of “Indianizing” should be proposed, tested, and applied to ensure Sustainability and Built Heritage. As mentioned, there is a dire need to curb the “Dazed” Built Heritage looking through the “Glasses” of the West and to propose a comprehensive guide with “Time-tested” solutions for various parameters of Sustainability. This can be done through devising the Evaluation Criteria for Built Heritage for Indian Medieval Cities. Lightning talk in the session and a poster
Tusharkanti Kumar Integrating ecosystem services in the institutional setup for waste management in a mountainous urban settlement – The case of Leh in Himalayas, India  Urbanisation poses inevitable challenges to regions and institutional mechanisms across the world. When these processes occur in mountainous regions, there are the added concerns of disrupting the sensitive ecological context. This study takes the case of Leh town in Ladakh region of the Himalayas in India. With an average altitude above 3000m, the region has extreme climatic conditions and a sensitive cold desert ecosystem. Being the largest settlement and district headquarters, it is experiencing unprecedented socio-economic changes due to exponential increase in tourism and allied activities. A floating population of almost 8-10 times the resident population of the town creates a consumer-led market economy which is completely detached from the ecosystem services of the region. This results in a stress on the scarce natural resources in the area. Management of the municipal solid waste has become a primary concern for the local authorities in recent years. The problems of excessive generation of waste, lack of management, and inappropriate disposal characterise a linear economy. Interview surveys and documentary reviews have been conducted to analyse the intensity of the situation. The traditional forms of construction, land use, and livelihood present a resource-efficient system rooted in the ecosystem services of the region. The research investigates ways of integrating ecosystem services and indigenous knowledge systems into the regional planning mechanism, as a crucial step towards development of a circular economy. A nexus between ecosystems approach and the institutional mechanism can help in reducing the trade-off between economic sustainability on one hand, and social and environmental sustainability on the other. Lightning talk in the session and a poster