Search

Recent research and IPCC reports extensively document the varied effects of climate change on basins worldwide. This study evaluates the impact of climate change and land use change on the Seti-Gandaki watershed's hydrological regime of Nepal. Using a calibrated hydrological SWAT model, forced with climate scenarios (SSP245 and SSP585), the study projects increased precipitation (2-129% and 3-139%) and a warming trend in temperature. Streamflow at the watershed’s outlet is expected to rise (up to 49% in monsoon, 96% in winter in SSP245; up to 61% in monsoon, 89% in winter in SSP585), with increased flow extremes, potentially leading to floods and landslides. The combined impacts project a 52-125% increase in streamflow in SSP245 and a 100-136% increase in SSP585, attributed to the shift from rural to urban settlements. These findings provide crucial insights for water resource planners and managers to develop location-specific strategies for sustainable water resource use in the Seti-Gandaki Watershed.

Climate variability and insufficient irrigation are primary constraints to stable and higher agricultural productivity and food security in Nepal. Agriculture is the largest global freshwater user, and integration of surface- and ground-water use is frequently presented as an strategy for increasing efficiency as well as climate change adaptation. However, conjunctive management (CM) planning often ignores demand-side requirements and a broader set of sustainable development considerations, including ecosystem health and economics of different development strategies. While there is generic understanding of conjunctive use, detailed technical knowhow to realize the CM is lacking in Nepal. This article presents a holistic framework through literature reviews, stakeholders consultations and expert interviews for assessing CM and implementation prospects from a systems-level perspective. We demonstrate the framework through a case study in Western Nepal, where climatic variability and a lack of irrigation are key impediments to increased agricultural productivity and sustainable development. Results show that knowledge of water resources availability is good and that of water demand low in the Western Terai. Additional and coordinated investments are required to improve knowledge gaps as well as access to irrigation. There is therefore a need to assess water resources availability, water access, use and productivity, to fill the knowledge gaps in order to pave pathways for CM. This paper also discusses some strategies to translate prospects of conjunctive management into implementation.

Floods pose significant risk to riparian buildings as evidenced during many historical events. Although structural resilience to tsunami flooding is well studied in the literature, high-velocity and debris-laden floods in steep terrains are not considered adequately so far. Historical floods in steep terrains necessitate the need for flood vulnerability analysis of buildings. To this end, we report vulnerability of riparian-reinforced concrete buildings using forensic damage interpretations and empirical/analytical vulnerability analyses. Furthermore, we propose the concept and implications of functionality loss due to flooding in residential reinforced concrete (RC) buildings using empirical data. Fragility functions using inundation depth and momentum flux are presented for RC buildings considering a recent flooding event in Nepal. The results show that flow velocity and sediment load, rather than hydrostatic load, govern the damages in riparian RC buildings. However, at larger inundation depth, hydrostatic force alone may collapse some of the RC buildings.