This article examines the landslide hazard mapping in Leoutikhola watershed of Dhankuta district, eastern hills of Nepal. The hills are regarded as one of the most vulnerable areas in the world. The area is prone to different types of natural hazards such as landslide, debris flow, gully erosion, mass wasting, and flooding. Various studies pointed out biophysical and socioeconomic factors are more responsible to landslide hazards in the hill-slope environment. This paper argues that the rainfall intensity, unscientific methods of cultivation and lack of environment friendly developmental activities in steep slope are some of the major driving factors to landslide in the Leoutikhola watershed area. Leoutikhola watershed area has been suffering from different types of natural hazards such as landslide, debris flow, gully erosion, mass wasting and flooding. Field verification and satellite imageries are the major sources for the information to analyze. Due to its fragile and very weak geological condition, geomorphic hazard is considered more common than other types of hazards which lose massive lives and property in the study area. The field observation and local people perception indicate a large amount of budget required to mitigate natural hazards in this area especially for landslide. In this context, this paper attempts to portray the landslide hazard zonation and susceptibility mapping correlated with various factors. For this purpose, bivariate statistical index and Geographic Information System (GIS) and Remote Sensing (RS) tools are used to calculate weighted values. The overall parameters indicate that in the series (-4.2 to 4.58) of five different hazard zones like very low, low, moderate, high and very high. The paper concludes that hazard determination calculated values indicate to 4.2 to -2.09, -2.09 to -1.0, -1.0 to-0.05, -0.05 to 1.24 and 1.24 to 4.58 respectively in the range of quartile series.

Land-water interfaces of lakes are highly dynamic and are responsible for the stability and maintenance of ecosystems. This study was carried out to understand the ecotone vegetation and the physico-chemical characteristics of waters of Begnas and Rara lakes of Nepal. For vegetation survey, line transects (perpendicular bi-sector to lake boundary), were used along the lake boundaries at an interval of 500 m; three quadrats of 1 m x 1 m size were laid on each line transect (off shore, boundary line, and on shore). All vegetation species in the sample quadrates were recorded. For probing water quality, lakes were divided into three blocks, then sampling was conducted on a consecutive day. Physico-chemical parameters —temperature, pH, electric conductivity (EC), dissolved oxygen (DO), total dissolved solid (TDS), ammonia, and nitrate—were measured. A total of 55 species under 38 families and 28 orders were recorded from ecotone of Begnas lake. In Rara lake, 56 species of 41 families and 22 orders were recorded. Poaceae was the dominant largest family in Begnas which was followed by Asteraceae. In Rara lake, Rosaceae was the dominant family which was followed by Pinaceae. Temperature, pH, and DO values decreased with depth, but EC and TDS e increased with depth, in both Begnas and Rara lakes. Ammonia and Nitrate were below the detectable limit of the instrument, indicating low nutrient contents of both lakes. The study established the baseline information about the diversity of ecotone vegetation; both the lakes show clear changes in physiochemical parameters with lake depths.

Groundwater served as the major source of water for existing biophysical species in an ecosystem. In recent years, depletion of the level of groundwater becomes an emerging serious environmental issue due to the anti-reciprocal man and human activities such as global climate change. This study aims to examine the groundwater potential areas using the semi-qualitative research design, based on Analytic Hierarchy Process. The focused is based on the Geographic Information System for the analysis of determining factors, such as distance from the stream and river, precipitation, pond frequency, normalized difference water index, land-use/land cover, drainage density, slope gradient, soil, and topographic wetness index. The Receiver Operating Characteristics were used to check the accuracy of the final calculated map of the groundwater potential zone. The 5 points Likert scale ranges very poor (1) to very high (5) used to analyse the groundwater potential zones. The result shows that 0.81 percent area is very poor for the potentiality of groundwater in the study area. Other scale contained 8.13 for poor, moderate (19.94%), high (39.72%) and very high potential zones (31.41%). The Receiver Operating Characteristics result showed that under the curve success rate is 0.64% and the prediction rate is 0.76%. This result shows a reliable degree of predictability of groundwater near the spatial distribution of marshes, lakes, and water bodies in the study area. The finding shows that the very high potentiality of groundwater areas are determining by the factors of precipitation, pond frequency, distance from river and stream, drainage density, land-use/land cover, soil, and slope in the study area. The result of this empirical analysis can be applied to analyze sustainable and effective water resources management activities.

Lake evolution and its changes over time are an evident and easily measurable signal of human activities and climate change impacts in mountain regions. This study presents bathymetric modeling of permanent lakes (Begnas and Rara Lakes) located in two different geographic settings of Nepal. Moreover, temporal changes in land cover and soil erosion of the lake watersheds, as well as climatic trends around these lakes, are assessed. This study supports establishing reference sites for exploring scientific evidence on the impacts of anthropogenic and climate change on lake hydrological systems. Second-order polynomial models best represent the relationship between lake depth and volume. Rara Lake had a maximum depth of 169 m with an area of 10.52 km2 and a volume of 1013.305 million cubic meters (Mm3), whereas Begnas Lake had a maximum depth of 12.5 m with an area of 2.98 ± 0.10 km2 and a water volume of 13.539 Mm3 in the year 2019. Both lake regions are experiencing changes in temperature and rainfall. The area and volume of Rara Lake and its watershed have been relatively stable even with minimal land-cover change during the recent decades. Begnas Lake and its watershed have experienced significant changes in the last few decades. This study concludes that human activities in the Begnas Lake watersheds are the primary source of lake area variation rather than climate change.

Agriculture practice on hill-slope terrain depicts the sensitivity indicators of the vulnerability in terms of global climate change. The major aims of the present research are to assess the land-use pattern conditioned by existing hill-slope terrain based on different land capability class recommend by land resources mapping project, 1986 in the Pikhuwa sub-watershed of Mid-hills, Bhojpur, Nepal. An overall research data derived, processed and analyzed using Geographic Information System and Remote sensing tools and techniques. The land capability class, current land-use and digital elevation model with 30 meter spatial resolution have primarily considered as a major variable for spatial analysis. The analysis estimated about 33.68% individual area of overall agriculture patches have remained on above 30 degrees slope of the terrain topography, which denotes the condition of land-use is not suited technically based on land capability class and recommendation made by LRMP, 1986. In the sub-watershed, the current land-use condition on hill-slope is being much vulnerable due to the steep slope, poor slope terracing and unmanaged surface runoff during monsoon.