http://localhost:8081/jspui/handle/123456789/11 2026-10-17T02:48:39Z http://localhost:8081/jspui/handle/123456789/20824 Title: Impact of climatic parameters on NDVI in Mahanadi Catchment, India Authors: Singh, Abhishek Pratap Abstract: This report presents the analysis of interannual and seasonal vegetation trends (i.e., Greening and Browning) based on the data derived from satellite images using Normalized Difference Vegetation Index (NDVI) and its response with Climate extremes over the Mahanadi catchment, using the MODIS NDVI produced on 16-day intervals and at multiple spatial resolutions for the period 2001 to 2019. NDVI and climatic parameters trend analysis methods and correlation analysis are applied. From the results, a greening (positive) trend in the annual NDVI and the monsoon NDVI has been observed, whereas the annual rainfall showed a negative trend and annual temperature showed a positive trend. All the extreme precipitation indices, that is, Consecutive dry days (CDD), Consecutive wet days (CWD), torrential rainfall days (R24), precipitation days (R0.1), showed a negative trend. The temperature extremes indices; Mean maximum temperature (Txav) and mean minimum temperature (Tnav), showed a positive trend. From the correlation analyses, a negative and weak correlation has been found between NDVI and precipitation extreme indices, and a positive correlation has been found between Mean minimum temperature and NDVI. A positive correlation exists between NDVI and Rainfall during the Monsoon season. The results indicate that the decrease in precipitation extremes may trigger the NDVI increase over the last two decades. A slight increase in the mean minimum temperature has a possible positive impact on the vegetation ecosystem. 2021-06-01T00:00:00Z http://localhost:8081/jspui/handle/123456789/20823 Title: Understanding the Hydrological Response of a Forested Watershed Garhwal Himalayas, Uttarakhand, India Authors: Assefa, Alebachew Halefom Abstract: The hydrological dynamics of dense forest cover catchments are highly complicated. Precipitation, soil storage water, actual evapotranspiration, surface runoff, base flow, and soil erosion are the most frequently used hydrologic components. Precipitation is a critical input into the process of hydrology and plays a vital role in understanding watershed response. Field observations using hydro-meteorological and hydrological data are required to comprehend the behavior of forested watersheds. Specifically, the baseflow of various rivers have been declining in the lesser Himalayan region. Further, sediment transport from high mountainous to lowland areas has significantly increased, which an essential geomorphological process. Both baseflow reduction and the increase in sediment transport require attention in the current times. In addition to these above processes understanding, actual evapotranspiration and groundwater recharge estimations are very less understood, and difficult to measure for forested watersheds in the mountainous regions. This study aims to understand the hydrological responses of a forested watershed, i.e., the Kempty watershed located in Garhwal Himalayas, Uttarakhand, India, using different hydrological tools and methods. Data have been received for five years and nine years from the meteorological and hydrological stations within the Kempty micro-catchment (January 2015 through September 2020). The monsoon is the major contributor every year to the seasonal and annual rainfall pattern. Analysis showed that the annual rainfall days varied widely from 66 to 185, so much during the monsoon season. This study also analyzed the streamflow discharge components, specifically the baseflow using a Hydro-Office (BFI+3) hydrograph separation model over the 16 months. The outlet monthly average discharge values reduce to 0.027 and rise to 0.203 m3/s in June and August 2020, respectively. The stream flow and storm flows at the outlet have shown a weak relationship with the rainfall. Other factors like rainfall intensity, duration, and watershed parameters influence their relationship. The baseflow analysis explained that the peaks of baseflow had been seen during monsoon periods and an average base flow index value at 0.92, showing much of the streamflow comes from the subsurface flow. As a result, the runoff coefficient for June-July-August (JAS) 2019 and JAS 2020 is 0.43 and 0.39, respectively. Seasonal and annual amounts of rainfall and streamflow strongly influenced annual suspended sediment flux. Mostly during the rainy season, 82% of the yearly load is being generated and only 6 peak flow events accounted for 40%. Monthly denudation rates for viii | the given study period range between 0.13 to 1.67 mm/year in August and December, respectively. The average monthly denudation rate is at 0.73mm/year. Actual evapotranspiration (AET) is estimated and compared using soil water balance, sink term, and soil water reduction (SWR) method from the five-year study period from the monthly recorded volumetric water content. Water balance, sink term, and soil water reduction methods estimated average monthly AET as 259.03 mm, 232,57 mm, and 330.61 mm respectively. The temporal variability of estimates of AET showed that water balance and sink term estimated similar values, except for insignificant changes. In contrast, the soil water reduction method estimated much higher than the other two methods. Since the SWR method showed higher temporal variability, we took the water balance estimates to calculate the groundwater recharge. Groundwater recharge estimated on average of 195mm per month using the water balance method. The monthly average of change in Ground water storage (ΔGW) is obtained 148mm. The present study shows that during the rainy season period, precipitation was the biggest factor in a watershed hydrologically properly working, while forests are providing significant services via control of water balance, soil moisture, and sediment through various forest-scale mechanisms in the Garhwal Himalayas. 2021-05-01T00:00:00Z http://localhost:8081/jspui/handle/123456789/20822 Title: Analysis of Hydro-climatic extremes in Upper Indus Basin Authors: Kumar, Aman Abstract: Hindu Kush Himalayan region, a crucial geo-ecological region, comprises one of the world’s most significant mountain systems. The Indus River originates in this region and feeds over 270 million people across six countries, including India. This study analyzed precipitation trends, trends in extremes, and dry and wet spells in the Upper Indus Basin located within latitude 31-37oN and longitude 72-82oE with elevation ranging from 944 m to 8533 m above mean sea level. The analyses of extreme events follow World Meteorological Organization guidelines on analysis of extremes. ETCCDI/CRD climate change indices used to perform dry and wet spell analysis. 1332 station data are analyzed to find the spatial variability throughout the basin. Wavelet coherence and continuous wavelet analysis were on the APHRODITE data with 0.25x0.25 grid resolution daily precipitation (1952-2014). Our study brings out the hidden trend in extreme events in the world’s most susceptible climate region. Nine annual, eight seasonal, and 24 monthly extreme climate indices study calculations are in our research. Then the trend analysis done for the same further part of the study considers wavelet analysis to examine the periodicity and the effect of climate anomalies on the upper Indus Basin. Our results indicate the significant increasing trend in total precipitation for364 stations on an annual basis. Furthermore, the season of a significant increase in precipitation is JJAS, i.e., monsoon. Heavy precipitation for 250 stations and very wet days for 20% of total stations are increasing significantly. Consecutive wet days for 272 stations. The monsoon has an increasing trend of extreme precipitation that increases the wet day of the season, and the dry period's consecutive length is also increased significantly for 137 stations. In July, max 1day precipitation increased significantly for 327 stations. The wavelet coherence analysis significantly correlates with extreme precipitation indices and climate anomalies with different periodicity at different scales. 2021-06-01T00:00:00Z http://localhost:8081/jspui/handle/123456789/20821 Title: Flood Plain Zoning Using HEC-RAS for Subarnarekha River Basin in Odisha Authors: Jena, Ananda Kumar Abstract: Flood management has become a growing concern for city managers and disaster risk prevention agencies worldwide. Hence, large investments are made towards data collection, archiving and analysis, and technologies such as geographic information systems (GIS) and remote sensing which play an important role. GIS technologies offer valuable means for delineation of flood plains, zoning of areas that need protection from floods, and identification of plans for development and scoping of various kinds of flood protection measures. Flood inundation maps (FIMs) are particularly useful in planning flood disaster risk responses. Floodplain zoning is significantly affected by the diverse and concurrent uncertainties that characterize the modeling chain used for producing inundation maps. To quantify the relative impact of the uncertainties linked to a lumped hydrological (rainfall-runoff) model andFLO-2D hydraulic model, an HEC-RAS procedure is used in this work. This flood analysis is carried out in the Subarnarekha river basin in India, by comparing the different frequency, extent, and depth of inundation simulations associated with varying rainfall forcing and/or hydraulic model roughness realizations. The hydrologic model HEC-HMS has also been used to get the runoff at a junction Deulbar on the mainstream of Subarnarekha. Then after getting the junction discharge, both 1D and 2D HEC-RAS modeling has been performed from the junction to the Rajghat outlet. Flood plain zones for six different return period floods have been found out from 10 yr,25 yr,50 yr,100 yr,500 yr& 1000 years respectively, showing increasing order of inundation areas. Thus this reach of the mainstream can be divided into six different zones and regulation of land use can be thereby restricting the damages caused by floods. Thus, this can be one of the non-structural measures to be contemplated. 2021-06-01T00:00:00Z