Srikantha Herath

Case Studies and National Experiences

Landslides continue to be a major natural disaster causing loss of life, extensive human suffering and economic losses, despite advances in understanding of mechanisms, monitoring and mitigation technologies related to landslides. Sharing the globally accumulated expertise and implementing this knowledge effectively in different local contexts is the major challenge now facing landslide loss reduction efforts. Landslides characteristics differ according to climatic, geological and geographical conditions. They are also affected by different triggering mechanisms depending on the livelihood practices, infrastructure development and population density in each locality. Landslide risk reduction practices and institutional arrangements have evolved in different countries in response to varied landslide experiences brought about by these different geo-physical characteristics and drivers. An objective analysis of the practices adopted worldwide would provide invaluable guidance to develop pragmatic landslide risk reduction strategies and responsible institutions, especially in the developing countries where the impacts are greatest and the vulnerabilities are the highest, especially with increasing hazard potential due to climate change. This chapter describes national programs and methodologies adopted in landslide risk reduction in various countries as a contribution in this direction

Hydrogeochemical Evolution and Appraisal of Groundwater Quality in Panna District, Central India

Intense agricultural and mining/industrial activities make groundwater quality vulnerable to contaminants. This study conducted in one of the mining areas of Panna district evaluated the factors influencing the groundwater hydrogeochemistry using water quality parameters and multi-isotopic approach considering the fact that groundwater is the only major source of drinking water. Forty-five water samples comprising both shallow and deep aquifers were collected and analyzed for major ions, δ18O, and δD. The geochemical data were used to characterize and classify water samples based on a multitude of ion plots and diagrams. The groundwater in the region is found to be contaminated with fluoride and nitrate. The sources for fluoride are mostly geogenic in nature. The alkaline nature of groundwater triggers replacement of the exchangeable fluoride from minerals like biotite/muscovite and results in its enrichment. In addition, it is contributed through leaching of fluorides from granitic rocks, abundantly present in the study area. The weathering of these fluoride-bearing minerals releases fluoride into the groundwater. On the other hand, nitrate enrichment is mainly attributed to leaching from untreated sewerage system and agricultural runoff containing nutrients from excess use of fertilizers. The stable isotopic composition for most of the collected samples was found to be near the local meteoric water line (LMWL), i.e., origin of ground water is meteoric in principle; however, the point away from the LMWL might favor exchange with rock minerals and evaporation processes. This study sets an important background for decision makers to take the suitable countermeasures from the public health perspective for sustainable water resources management.

Improving global rainfall forecasting with a weather type approach in Japan

ABSTRACT An automated version of the weather type classification scheme was performed over Japan to characterize daily circulation conditions. A daily gridded field of mean sea-level pressure (MSLP) from the European Centre for Medium-Range Weather Forecasts (ECMWF) Re-Analysis dataset (ERA-interim) and the THORPEX Interactive Grand Global Ensemble (TIGGE) daily forecast dataset were used. The weather type is advantageous as it provides an opportunity to improve global rainfall prediction by refining statistical bias correction. We distinguished 11 weather types: anticyclone, cyclone, hybrid and eight purely wind directions. The results indicate that the main weather types contributing to the total volume of rainfall are cyclone, hybrid, purely westerly and northwest winds. A gamma-based bias correction decreases the global rainfall forecast root mean square by 10%, while specific weather type gamma bias correction accounts for 5–10% root mean square error reduction, with a total decrease of errors up to a maximum of 20%. Both global and weather type bias corrections improve the extreme dependency scores (EDS), but for different extreme rainfall thresholds. The study advocates the use of weather type bias-correction methods for extreme event rainfall intensity corrections higher than 100 mm/d. EDITOR A. Castellarin ASSOCIATE EDITOR A. Jain

Local perceptions of climate change and adaptation needs in the Ifugao Rice Terraces (Northern Philippines)

The Ifugao Rice Terraces in the Philippines is recognized worldwide as a sustainable landscape where humans live in harmony with nature. The success of the Ifugao Rice Terraces largely depends on the attunement of local farmers to their environment and their ability to adapt to perceived changes, as manifested in their complex body of traditional ecological and climatic knowledge. This paper examines the local perceptions on climate change and other challenges to sustainability through focus group discussions with farmers and traditional knowledge holders. Our main findings can be summarized as follows: (i) Ifugao farmers were able to observe climatic changes in recent years, and these changes were intimately linked with broader environmental and socio-cultural changes in the Ifugao social-ecological system; (ii) The climatic changes qualitatively observed by the farmers were in agreement with trends in datasets commonly used in scientific assessments, although this agreement depends on the spatial and temporal resolution of the dataset, and the type of statistical analysis performed, and; (iii) The Ifugaos stressed the importance of traditional knowledge and culture in climate change adaptation, and preferred measures which could increase internal adaptive capacity while addressing broader sources of community vulnerability. Our results support calls to recognize Indigenous and Western science as equally valid ways of knowing. Discussions with the farmers revealed that in the Ifugao context, climate change may be better framed in the context of multiple stressors on rural livelihoods, with adaptation integrated into broader development objectives. Our findings also emphasize the need for greater engagement of indigenous Ifugao people in planning processes in order to identify adaptation strategies that are culturally appropriate, equitable, and effective in responding to local needs.

Decision Support Systems for Water Resources Management in Dudhi and Bewas Watersheds, Madhya Pradesh, India

In recent years, the concept of watershed management has grown rapidly due to the importance of water as an increasingly precious natural resource that is, at the same time, very difficult to manage within the overall development of any nation. Watersheds integrate many physical, biological, social and economic processes and information. Water resource management is a continuous process requiring attention at various levels because of its inherent nature and the extent of interventions being made at various levels and scales. Small-scale interventions, at the village level, are mainly for soil and water conservation and fulfil the require- ments of a small community. It is essential to generate biophysical information that can be used to generate scenarios, which in turn can help in local-level planning and management of land and water resources in the watersheds. The present study demonstrates the methodology for development of a decision support system for planning a sustainable watershed management programme at village level which can be used for sustainable root level planning for development, implementation, monitoring and evaluation of watershed management programmes in semi-arid regions.