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TUE7.7: Ecosystem based approaches
Geospatial pattern and trend in temperature and rainfall in Bangladesh
1Bangladesh Centre for Advanced Studies (BCAS), Bangladesh, People's Republic of; 2Institute of Forestry and Environmental Sciences, Chittagong University (IFESCU)
The main objective of this study was to identify the changing pattern of temperature and rainfall for better understanding the monsoon behavior in a changing climate scenario. For the study, last 30 years (1978 to 2007) temperature and rainfall observation data of 34 weather stations of Bangladesh were collected and analyzed. The result reveals that average temperature in Bangladesh is increasing for all the four seasons: In pre-monsoon (March-April-May) at a rate of 0.0150C; in monsoon (June-July-August) 0.0140C; in post monsoon (September-October-November) 0.0100C and in winter (December-January-February) 0.0090C per year. Conversely, average rainfall is also increasing at a rate of 3.346mm/year in monsoon and 8.084mm/year in post monsoon. The research also found a significant linkage between temperature and rainfall in pre-monsoon and winter seasons: For an increase of 1°C average maximum temperature in pre-monsoon rainfall may decrease by 153 mm while 1°C increase in average maximum temperature may cause a decrease of 23 mm rainfall in winter season. South eastern region which is one the most important forest ecosystem zone in the country is experiencing early onset and withdrawal of rain whereas increasing trend in total rainfall except in monsoon season. This means the region is experiencing less number of rainy days. However, total rainfall has not changed significantly. On the other hand, maximum temperature showed increasing trend while minimum temperature decreasing which means the temperature differentials in the region is increasing. This changing pattern in average max and Min temperature along with precipitation might cause a situation that the species which are growing now may shift to suitable habitat elsewhere in future. Consequently the forest and biodiversity, watersheds and fisheries, productivity of land, agriculture and food security in the region will be affected by these observed changes of climate.
Role of thematic resettlement as eco-village in Sri Lanka
1Kansai University, Japan; 2Kyoto University, Japan
As part of Indian Ocean Tsunami recovery projects, an “eco-village” was established in Lagoswatta, located in the Kalutara district near Colombo in Sri Lanka. 55 tsunami affected families, from 8 different communities, were relocated to the eco-village. The project was supported by local NGO, and UNEP and UN-HABITAT initiated the Eco-housing project in 2004 to build capacity and to increase awareness on this issue. The main environmental activities includes: i) classification of garbage by type, ii) composting, iii) using natural energy such as rainwater tank and solar panel, ix) eco-friendly housing design, and x) workshops on the environment which were conducted by local NGO. This case study aims to show the impacts of the thematic resettlement as eco-village through field survey conducted between 2006 and 2010. Questionnaires and interview surveys were conducted at 55 households. Observation survey involved understanding the changing of the community structure and physical life condition in the resettlement area. Through this research, two major findings were found. Firstly, out of the five activities carried out in the eco-village concept, only compost activity remained. Since the people did relocate to the new area due to interest in eco-activities but were resettled due to the tsunami, it would have been more appropriate if the housing were designed based on the local needs and requirements. Second major finding concerns the possibility of eco-village building in post-disaster. If the focus is on ‘community recovery’, an eco-village concept may be effective in achieving sustainable resettlement. Environmental activities created a common purpose, providing people the opportunity to communicate with each other, in turn, enhancing bonding within the community. To achieve sustainable resettlement, decision-makers should not only focus on the physical policy such as housing and infrastructure construction approaches and distribution of benefits, but also consider the social impacts such as human relationships internal/external community.
Study of agricultural drought coping and ecological feedback - taking Hebei Province in North China as an example
11 Hebei Normal University, China, China, People's Republic of; 22 Hebei Key Laboratory of Environmental Change and Ecology Construction; 33 Hebei Technology University, China, China, People's Republic of
Drought is the biggest challenge for the agriculture in North China. It is necessary to understand and make clear the background, process, and current state of agricultural systems’ vulnerability. There exists a complex feedback mechanism between drought driving forces and physical ecology. Taking Hebei province in North China as an example, this paper analyzes the strategies of drought coping under current conditions, the feedback process and mechanism of ecological systems, and considers the implications for sustainable drought management. The study shows that drought, water scarcity and the current increase in gross grain output is a sharp contradiction in Hebei province. The driving forces of drought disasters are from both physical and social economic systems. Here rainfall downward fluctuation and temperature rises due to climate change lead to intensive evaporation, and thus makes meteorological drought more frequent. River flows from outside areas and river flows generated from within Hebei decreased dramatically, and reduced the total surface water volume in recent decades. With water demand increasing, over drawing of groundwater has been occurring in the Hebei plain area. Consequently, the groundwater table has been lowering year after year. The world’s largest funnels are forming and expanding, and ground subsidence is common. Here, improved irrigation measures encourage water consumptive crops and multi-plough agricultural systems, which lead to dramatically increasing grain output volumes, and the subsequent demand for much more water. The combined effect speeds up water depletion and ruins the agricultural ecosystem in return. For sustainable development, a more adaptive and resilient agricultural system must be build. The strategies are as follows: adjusting crop structure based on available water resources, improving drought monitoring and emergency management, designing and building water saving projects, establishing a more water saving society, selecting drought endurance crops, improving field management technology, providing public services, and ameliorating the overall ecological system.
Assessment effects of River Vegetation Density Index (RVDI) in recognition of damageable areas during torrents
Tarbiat Modares University, Iran, Islamic Republic of
Existence of different types of short, high and dense vegetation in main channel and ﬂoodplain of rivers can cause eliminate water energy, flow lag, river depth rise, river out-pour and financial and soul damages. Correct analysis of flow condition for damageable area projects (DAP) in these parts of rivers needs careful estimates of flow resistance coefficient. This study was performed with the aim of assessment of interaction of vegetation and water depth in rivers during torrents to recognize the submerged areas and manage them. A series of experiments with 3 uniform and steady discharges (Q) and 4 density of vegetation in various sets with use of vegetation density index (RVDI) were performed in a compounded flume in Tarbiat Modares University approximately like a real river. The calculated resistance coefficients (n) in various depth’s ratios (DR) and obtained equations of Q-n and n-DR showed that in low discharges the effect of vegetation in resistance coefficient is deniable, but with rise in discharge like during torrents the resistance coefficient and corresponding DR are very influenced. Results showed with 37% increase in water discharge, resistance coefficient increases about 15.5% that makes rise in water depth. We conclusion that estimation of resistance coefficient in vegetate rivers with common calculation ways without considering vegetation effects can cause of underestimation in water depth, wasteful and unsafe DAPs; but we can estimate careful values with use of obtained equations.