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Subject: Soil and Water Engineering × End date: 2024 × Start date: 2020 × Type: Thesis × Thesis Type: Ph.D ×
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    ThesisItemOpen Access
    Hydrological modelling using SWAT and effect of climate change on rainfall, runoff and sediment yield in the Naula Watershed, Uttarakhand
    (G.B. Pant University of Agriculture and Technology, Pantnagar, District Udham Singh Nagar, Uttarakhand. PIN - 263145, 2021-11) Saran, Bhagwat; Anil Kumar
    Soil and water is one of the most important natural resources for the survival on the earth. Without soil and water the life on the earth is not expected. At present increasing the rate of soil erosion is the matter of serious concern to feed such a huge population. Considering the above facts the present study is undertaken to assess the hydrological behaviour of Naula watershed. In this study the physically based Soil and Water Assessment Tool (SWAT) model was used to simulate the runoff and sediment yield from the Naula watershed of Ranikhet, Uttarakhand, India. The data used for this study was runoff and sediment yield from the year 1980 to 2012, two years of data (1980-1981) were used to warm up of the SWAT model. The calibration was performed using monthly observed data of runoff and sediment yield from the year 1982 to 2002 and that model was validated using same data from 2003 to 2012. The calibration and validation analysis of the model has been carried out at Naula watershed using SWAT-CUP with the algorithm SUFI-2 (Sequential Uncertainty Fitting) for the runoff and sediment yield. The results of monthly Nash-Sutcliffe efficiency (NSE), coefficient of determination (R2), percent bias (PBIAS) and RMSE-observations standard deviation ratio (RSR) were found to be acceptable for both calibration and validation period. The NSE, R2, PBIAS and RMSE for the runoff simulation were found as 0.68, 0.68, -3.3 and 0.56 during calibration period and 0.62, 0.64, -12.8 and 0.76 for the validation respectively. For the simulation of sediment yield using SWAT-CUP, the NSE, R2, PBIAS and RMSE were found as 0.69, 0.73, -1.3 and 0.56 for the calibration period and 0.75, 0.76, -2.6 and 0.51 for the validation period respectively. NDVI and LULC change detection were also analysed in this study. The highest NDVI values were found as 0.64, 0.72 and 0.55 for the year 2000, 2010 and 2020 respectively. In the LULC change detection, the land covered by the agriculture was 13.87 %, mixed forest 1.95 %, shrub land 6.59 %, barren land 0.58 %, fallow land 11.63 %, water body 0.49 % and evergreen forest 64.85 % of the total area for the year of 2000. However, the area of agriculture and forest gradually decrease while the area of barren land and fallow land increase in the year 2000-2010. In the year 2010-2020; the agriculture land and forest land, fallow land decrease and barren land increases twice as compared to previous year. The area of water body increases very less from the year 2000-2020. Climate change was studied by determining the percentage change of rainfall, runoff and sediment yield from the year 2020 to 2052 (33 years) and 2053 to 2085 (33 years) with the base value of 1980 to 2012 (33 years).
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    ThesisItemOpen Access
    Nitrogen release, sediment outflow and water quality parameters with uncoated and neem coated urea application from selected land slopes under simulated rainfall conditions
    (G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2020-09) Singh, Sachin Kumar; Akhilesh Kumar
    The nutrients loss from fertilized agricultural lands not only results in the reduction of fertility of soil but also the accumulation of these chemicals in various water bodies produce harmful toxic effects rendering it unfit for human as well as for animal consumption. Urea fertilizer is highly soluble in water and volatile in nature and constitutes about 82% of the nitrogenous fertilizer used in India. The various pathways of nitrogen loss are volatilization, leaching, de-nitrification and through runoff. To minimize the nitrogen losses and environmental hazards, it becomes imperative to improve the efficiency of nitrogen use by controlling nitrogen release rate of urea as per the plants’ need. To accomplish this task, slowrelease fertilizers (SRF) are produced by coating urea with neem and other biodegradable materials. This neem coated urea helps in retaining nutrients for a longer time and ensures nitrogen availability to plants for significantly longer periods than an uncoated urea fertilizer. In this study extensive experimentation was done in the open field on experimental plots using uncoated and neem coated urea to study their nitrogen release pattern and its effects on sediment outflow and water quality parameters under varying rainfall intensity and different land slope conditions. To create controlled conditions of rainfall, artificial rainfall was generated by developing a portable rainfall simulation system which was capable of producing rainfall almost similar to natural rainfall with complete manual control. As per mandate of this study, apart from control (No crop i.e., bare soil), the nitrogen release rate, sediment outflow and water quality parameters were observed from (i) maize crop land and (ii) marigold crop land. Soil samples and runoff samples were collected and analysed to determine the status of nitrogen content in the soil and runoff water quality parameters such as TDS, pH and electrical conductivity on 2nd day, 6th day, 10th day and 14th after coated and uncoated urea applications. It was observed that developed portable rainfall simulator generated rainfall very similar to natural rainfall. The soil nitrogen content both in case of ordinary urea as well as neem coated urea applications was high in the beginning and decreased with time till 14th day. In case of ordinary urea, the rate of decrease in soil nitrogen content was very fast in the beginning (during 2nd day to 6th day) while in case of neem coated urea, the nitrogen release rate was slow and steady throughout the period. It thus implied that in case of neem coated urea application, the nitrogen becomes available to soil at a uniform rate for longer duration in bare land as well in crop land conditions. The percent nitrogen release up to 14th day after application of uncoated and neem coated urea with maize crop conditions was recorded to be 32.06% and 24.20% at 0% land slope, 33.11% and 25.23% at 2% land slope, 34.22% and 27.43% at 4% land slope, 37.68% and 30.60% at 8% land slope and 39.54% and 31.16% at 12% land slope, respectively under similar conditions. Similarly, sediment out flow and runoff water quality parameters were observed and analysed to see the effect of coated and uncoated urea applications under various combinations of input variables. To quantify the effect of involved variables on nitrogen release and water quality parameters, mathematical relationships were also developed for various combinations of the input variables.
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    ThesisItemOpen Access
    Swat based runoff and sediment yield modelling for upper Shivnath basin
    (G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2020-01) Singh, Vijay Kumar; Devendra Kumar
    The study was undertaken with the major objectives of calibrating and validating the Soil and Water Assessment Tool (SWAT) model to simulate surface runoff and sediment yield for the Upper Shivnath basin. The meteorological and hydrological data are used from 1990 to 1994 for warmup period, 1995 to 2005 for calibration period and 2006 to 2013 for validation period. The developed SWAT model accurately simulated runoff and sediment yield of Upper Shivnath basin. The Soil and Water Assessment Tool based Wavelet Multilayer Perceptron (SWAT-WMLP), Soil and Water Assessment Tool based Wavelet Support Vector Machine (SWAT-WSVM), Soil and Water Assessment Tool based Wavelet Multilayer Perceptron-Genetic Algorithm (SWAT-WMLP-GA) and Soil and Water Assessment Tool based Wavelet Support Vector Machine-Genetic Algorithm (SWAT-WSVM-GA) accurately simulated runoff and sediment yield in comparison to SWAT model. Three different statistical downscaling methods namely delta method (DM), quantile mapping method (QMM) and empirical quantile mapping method (EQMM) were used for downscaling precipitation. Delta method performed better than quantile mapping and empirical quantile mapping methods for downscaling of rainfall at all gauging stations. Impact assessment of climate change during 2020-2039, 2040-2059, 2060-2079 and 2080-2099 scenarios shows that runoff and sediment yield of most of sub-basins will slightly decrease in future. The effect of land use change on runoff and sediment yield were assessed using future use land of 2025, 2045, 2065 and 2085 periods. It was showed that the urban land will increase by 44.56 % during 2025, 71.06 % during 2045, 95.33 % during 2065 and 134.12% during 2085 respectively, while agriculture land will decrease by 2.10 % during 2025, 3.35 % during 2045, 4.49 % during 2065 and 6.30 % during 2085. The surface runoff and sediment yield will increase during 2020-2039, 2040-2059, 2060-2079 and 2080-2099 future scenarios due to impact of land use change.