What has happened to our lake? Characterizing the development of Kahphuche Lake in Nepal : A thesis submitted in partial fulfilment of the requirements for the Degree of Master of Applied Science at Lincoln University

The unfolding of Kahphuche Lake in the Himalayan foothills of western Nepal in less than two decades, at an elevation of 2,450 meters above sea level (m asl), below the accepted lower limit of glacier moraine accumulations in Nepal (i.e., 3,500 m asl) has provoked many questions and confusion regarding its glacier origins and future implications. Given the geographical complexity of seasonal and topographic variations of rugged terrain, coupled with the lack of extensive literature, it is a challenge to understand the development and dynamics of Kahphuche Lake. Thus, the principal aim of this study is to provide an in-depth insight into Kahphuche Lake’s formation and growth, classification, and its broader implications from an interdisciplinary approach. Two key sources of knowledge are integrated in this research – physical science methods using remote sensing and spatial data analysis, and qualitative insights obtained through key informant interviews. Merging remote sensing data with local knowledge that has been shaped by generations of lived experience who themselves have witnessed the lake’s evolution over time becomes indispensable in filling the gaps, providing a deeper perspective of Kahphuche Lake Catchment, its changes, and the underlying factors driving its formation and growth. Results revealed that Kahphuche Lake's formation is not limited to environmental components like glacier retreat and glacial meltwater. While previous studies attributed the formation of Kahphuche Lake to the accumulation of meltwater from avalanche deposits, this study strongly suggests that the debris- covered glacier origins of Kahphuche Lake make it a proglacial lake. The qualitative findings also serve as a powerful interpretive tool, enriching and validating the remote sensing analysis while highlighting how local communities perceive this lake as both a marker of environmental change and a cultural and livelihood resource. Consequently, challenging the conventional narrative of glacial lakes forming at elevations higher than 3,500 m in the Nepal Himalayas, the development of Kahphuche Glacial Lake at 2,400 m asl offers a new outlook on the region’s past glacial history and ongoing environmental change in an increasingly dynamic Himalayan landscape.