Papers by Tirtha Raj Adhikari
Journal of Hydrology and Meteorology
The availability of continuous hydrological records, both spatially and temporally, is often limi... more The availability of continuous hydrological records, both spatially and temporally, is often limited. This research employed a fully distributed Spatial Process in HYdrology (SPHY) model within the Tamakoshi River Basin to address this gap. The SPHY model was calibrated from 2004 to 2008 with NSE 0.62 at Busti station of Tamakoshi [2933.29 km2] and validated from 2004 to 2008 with NSE 0.76 at Rasnalu station of Khimti [322.58 km2]. Conversely, SPHY model was calibrated from 2004 to 2008 with NSE 0.79 at Rasnalu station of Khimti and validated from 2004 to 2008 with NSE 0.61 at Busti station of Tamakoshi. The observed annual average discharge at Busti station was 1632 m3 /s and Rasnalu station was 261 m3 /s during the simulation period. The annual average discharges at Benighat [862.09 km2 downstream] transferred from Busti and Rasnalu models are 1963.1 m3 /s and 1961.32 m3 /s, respectively. Daily streamflow generated at Benighat from Busti and Rasnalu stations, closely aligns and pe...
Journal of Mountain Science
Journal on Geoinformatics, Nepal
Nepal is mountainous country originates the several rivers, rivulets and tributaries in different... more Nepal is mountainous country originates the several rivers, rivulets and tributaries in different watershed systems mostly from higher level at north to lower level at south part of the country. Some research pointed prediction of the extreme flood level in such low land area can reduce hazard level significantly in the contest of Nepal. The HEC−RAS model is a one of the very successful tools for the rising of water level, flood hazard and inundation forecast purpose. Therefore, in the Chamelia river basin also applied this model for prediction of extreme flood analysis. In this regards Chamelia hydrological station observed extreme flood data (1965−2015) was used for frequency analysis by Gumbel’s method. The frequency analysis in different return period 2, 5, 10, 20, 50, 100, 200, 500 and 1000 year results generated design flood of 364 m3/s, 516 m3/s, 617m3/s, 713 m3/s, 838 m3/s , 932 m3/s, 1025 m3/s, 1149 m3/s and 1242 m3/s magnitudes respectively. Flood hazard maps were prepared...
Frontiers in Earth Science
Hydrological models are widely used and often regarded as reliable tools for accurately estimatin... more Hydrological models are widely used and often regarded as reliable tools for accurately estimating various components of the water balance. In a remote Himalayan catchment, such as Tamakoshi basin, where limited hydrometric dataset is available, such models often provide essential insights that are crucial to water researchers and planners. In this regard, we employed the semi-distributed HBV-light (version 4.0.0.25) hydrological model for glacierized Tamakoshi river basin and attempted to quantify various water balance components. For our model tests, using the daily streamflow records, we selected two distinct periods, i.e., 2004–2008 as a calibration period whilst 2011–2012 for model validation. Based on our findings, the model was able to reasonably predict the streamflow (validation efficiency: Nash-Sutcliffe Efficiency of 0.82 and percent bias −21%). At our site, HBV-light model predicted that the change in streamflow was mostly governed by monsoonal rain (62%) followed by bas...
Journal on Geoinformatics, Nepal
Nepal is mountainous country originates the several rivers, rivulets and tributaries in different... more Nepal is mountainous country originates the several rivers, rivulets and tributaries in different watershed systems mostly from higher level at north to lower level at south part of the country. Some research pointed prediction of the extreme flood level in such low land area can reduce hazard level significantly in the contest of Nepal. The HEC−RAS model is a one of the very successful tools for the rising of water level, flood hazard and inundation forecast purpose. Therefore, in the Chamelia river basin also applied this model for prediction of extreme flood analysis. In this regards Chamelia hydrological station observed extreme flood data (1965−2015) was used for frequency analysis by Gumbel’s method. The frequency analysis in different return period 2, 5, 10, 20, 50, 100, 200, 500 and 1000 year results generated design flood of 364 m3/s, 516 m3/s, 617m3/s, 713 m3/s, 838 m3/s , 932 m3/s, 1025 m3/s, 1149 m3/s and 1242 m3/s magnitudes respectively. Flood hazard maps were prepared...
Hydrology
Climate change and climate variability drive rapid glacier melt and snowpack loss, extreme precip... more Climate change and climate variability drive rapid glacier melt and snowpack loss, extreme precipitation and temperature events, and alteration of water availability in the Himalayas. There is increasing observational evidence of climate change impacts on water resource availability and agricultural productivity in the central Himalayan region. Here, we assess the farmers’ perception of climate change and its impacts on agriculture in western Nepal. We interviewed 554 households and conducted eight focus group discussions to collect farmers’ perceptions of temperature and rainfall characteristics, water availability, onset and duration of different seasons, and the impacts of such changes on their lives and livelihoods. Our results indicate that the farmers’ perceptions of rising annual and summer temperatures are consistent with observations. Perception, however, contradicts observed trends in winter temperature, as well as annual, monsoon, and winter precipitation. In addition, fa...
Many people travel to high altitudes for different purposes, mainly for trekking and expeditions.... more Many people travel to high altitudes for different purposes, mainly for trekking and expeditions. They may experience high altitude sickness and harsh weather conditions. Therefore, information on weather conditions before any travel is crucial for safety. Altitude sickness normally starts from the elevation above 3500 m. This study explores inter relationships between meteorological parameters and altitude sickness in the Khumbu Everest region and provides information about meteorological conditions during the high deaths. Percentiles and index basis criteria were used to evaluate sensitivity of death cases to meteorological variables. Atmospheric pressure, wind speed and minimum temperature recorded at the nighttime were more sensitive to deaths by high altitude sickness compared to precipitation, maximum temperature, wind speed, relative humidity, and sunshine duration.
Theoretical and Applied Climatology
Journal of Tourism and Himalayan Adventures
Many people travel to high altitudes for different purposes, mainly for trekking and expeditions.... more Many people travel to high altitudes for different purposes, mainly for trekking and expeditions. They may experience high altitude sickness and harsh weather conditions. Therefore, information on weather conditions before any travel is crucial for safety. Altitude sickness normally starts from the elevation above 3500 m. This study explores inter relationships between meteorological parameters and altitude sickness in the Khumbu Everest region and provides information about meteorological conditions during the high deaths. Percentiles and index basis criteria were used to evaluate sensitivity of death cases to meteorological variables. Atmospheric pressure, wind speed and minimum temperature recorded at the nighttime were more sensitive to deaths by high altitude sickness compared to precipitation, maximum temperature, wind speed, relative humidity, and sunshine duration.
Journal of Hydrology and Meteorology, 2016
For the protection of the environment, climatic water balance studies play key role. This study a... more For the protection of the environment, climatic water balance studies play key role. This study attempts to assess the potential water availability at the Annapurna, Langtang and Khumbu regions of Nepal Himalaya. Potential evapotranspitration (PET) is calculated by CROPWAT 8 with the help of maximum and minimum temperature, relative humidity, wind speed and sunshine hour. The climatic water balance of water bodies is calculated on the basis of Thornthwait procedure. These calculations help to examine annual water surplus (WS) and water deficit (WD) periods. Potential water surplus at three selected station is calculated by above techniques after averaging the data of time period from 1987 to 2008. The main aim of this study is to compare the obtained result from the climatic water balance for the selected sites of the Nepal Himalaya region. This study will provide climatic water balance information of the given area which will be useful for sustainable management of water resources in local and small area of the Nepal Himalaya.
This research paper provides the estimation of peak discharge from the Sangda River and Langtang ... more This research paper provides the estimation of peak discharge from the Sangda River and Langtang River of Nepal. Sangda River is located in Mustang district, Kagbeni VDC, western part of Nepal and Langtang catchment which is glaciered basin, located in central part of Nepal. On 17th April, 2012, the Radar Level sensor (RLS) was installed for the measurement of stage height on Sangda River, which is fed by glaciers from the Hidden Valley in which Rikha Samba Glacier is the biggest amongst all. The location of RLS is 83° 46’ 2.34”E & 28° 53’ 42’’N. On the basis of RLS location watershed is delineated and the area is 432.66 Km2. River Survey was carried out in January and March 2013 in Sangda and Langtang River. On the basis of flood marks peak discharge is estimated by using slope area method. Manning’s coefficient of 0.04 is used in both rivers. The peak discharge for Sangda River is estimated as 52.29 m3/s for 1.8 m stage height, while the actual discharge is calculated as 1.28 m3/s...
Fluvial floods drive severe risk to riverine communities. There is a strong evidence of increasin... more Fluvial floods drive severe risk to riverine communities. There is a strong evidence of increasing flood hazards in many regions around the world. The choice of methods and assumptions used in flood hazard estimates can impact the design of risk management strategies. In this study, we characterize the expected flood hazards conditioned on the uncertain model structures, model parameters and prior distributions of the parameters. We construct a Bayesian framework for river stage return level estimation using a nonstationary statistical model that relies exclusively on Indian Ocean Dipole Index. We show that ignoring uncertainties can lead to biased estimation of expected flood hazards. We find that the considered model parametric uncertainty is more influential than model structures and model priors. Our results highlight the importance of incorporating uncertainty in river stage estimates, and are of practical use for informing water infrastructure designs in a changing climate.
Extreme floods provide a design basis for flood-sensitive infrastructures. There is strong eviden... more Extreme floods provide a design basis for flood-sensitive infrastructures. There is strong evidence of climate change to alter the characteristics of extreme floods in the central Himalayan region, Nepal. However, current infrastructure design practices rely on the assumption of stationary flood peak records. Given the nonstationary behavior in extreme floods, traditional infrastructure design specifications may yield poor outcomes. Here we show that assuming climate stationarity can drastically underestimate extreme floods. We find that the uncertainty in extreme flood estimates is driven by complex interaction between uncertainties associated with data record length, model priors and model structures. Our results highlight the importance of incorporating climate nonstationarity into extreme flood estimates, and are of practical use for keeping infrastructure reliable over the service life.
Al-Ain is the second largest city in the Emirate of Abu Dhabi and the third in the UAE. Currently... more Al-Ain is the second largest city in the Emirate of Abu Dhabi and the third in the UAE. Currently, desalination plants are the only source of drinking water in the city with an average daily supply of 170 MIG. Recently, Abu Dhabi Urban Planning Council (UPC) released Al-Ain 2030 Plan. Projects suggested in this plan, over and above the expected natural population growth, will certainly put additional stress on the water resources in the city. Therefore, Al-Ain city seems to be in urgent need for an integrated water resources management strategy towards achieving sustainable development. This strategy will contain three main components; namely, a Water Demand Forecasting Model (WDFM), a Water Budget Model (WBM), and a Water Resources Optimization Model (WROM). The main aim of this paper is to present the WBM that estimates all inflows and outflows to assess water resources sustainability in the city. Key words integrated water resources; management; water budget; United Arab Emirates
Climate
Increasing evidence of changing climate patterns is being observed, and the impact of this change... more Increasing evidence of changing climate patterns is being observed, and the impact of this change on groundwater has a direct impact on the livelihood and economy of the region. The research focuses on the impacts of global temperature increase and changing precipitation on the groundwater resources of part of the Himalayan river system. The spatial and temporal variations of the hydro-meteorological data of the Kankai River Basin in East Nepal were analyzed using non-parametric Mann–Kendall tests and Sen’s Slope methods, whereas CanESM2 was used to predict the future precipitation scenarios, and an attempt has been made to evaluate the possible impacts on groundwater systems in the region. The temperature shows a significant warming trend (0.14–0.64 °C/decade); however, the precipitation trends suggest remarkable variation mostly at higher elevation. The average annual precipitation suggests a decrease of 1.82 mm/year and a similar decrement has been projected for the future. The g...
Annals of GIS, 2021
River flow exhibits morphological changes over time. The shifting of river channels is a common n... more River flow exhibits morphological changes over time. The shifting of river channels is a common natural phenomenon which often poses risk to life and property. Channel shifting is mostly associated with weak geology, extreme floods, and land cover alterations. Here we assess the changing morphology of the largest depositional landform in Nepal, called the Karnali Megafan, over the period of 1977–2013. We applied geographic information system (GIS) and remote sensing techniques to analyse the spatiotemporal changes in the Karnali Megafan. We obtained historical channel information from Landsat Operational Land Imager (OLI) and the Thermal InfraRed Sensor (TRIS) satellite image, Landsat Enhanced Thematic Mapper Plus (ETM+), Thematic Mapper (TM) and Multispectral Scanner (MSS) for years 1977, 1990, 2000, 2010 and 2013. The channel shifting depicts a generally increasing trend in the right branch while the trend is less prominent in the left branch. We find that the extreme rainfall and...
World Academy of Science, Engineering and Technology, International Journal of Environmental and Ecological Engineering, 2016
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Papers by Tirtha Raj Adhikari