Thumbnail Image

Theses

Browse

20212
Reset filters
Subject: Soil and Water Engineering × End date: 2021 × Start date: 2020 × Type: Thesis × Thesis Type: M.Tech. ×
Reset filters

Search Results

Now showing 1 - 2 of 2
  • Thumbnail Image
    ThesisItemOpen Access
    Effect of temporally distributed rainfall patterns on runoff-sediment outflow from lands under sorghum and urad crops and with furrow treatment
    (G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2021-02) Atul Prakash; Akhilesh Kumar
    In this study, laboratory experiments were conducted to assess the effect of temporally distributed rainfall patterns namely, Uniform rainfall distribution pattern (URDP), Advanced rainfall distribution pattern (ARDP), Delayed rainfall distribution pattern (DRDP) and Intermediate rainfall distribution pattern (IRDP) considering Sorghum and Urad crop lands and also lands treated with along the slope furrow and across the slope furrow on total runoff, average runoff rate, average sediment concentration and average sediment outflow rate under at selected land slopes. The observations were also analyzed to assess the efficacy of above soil biomass and below soil biomass of these cropping systems on runoff and sediment outflow. This study was conducted on experimental plots using artificially generated rainfall with the help of a rainfall simulation system of 3 m × 1 m size. Rainfall distribution pattern were created by using simulated rainfall and the simulator was operated for 30 minutes to provide a total rainfall of 4.4 cm depth. A comparison of observed values of runoff rate and sediment concentration for whole plant plot and below soil bio mass plot clearly revealed that the for whole plant plot, the lowest runoff rate occurred for URDP while the lowest value of sediment concentration was found in case IRDP at 4% land slope. For 8% land slope, the maximum average runoff rate and sediment concentration rate were observed in case of IRDP. This study clearly revealed that in case of below soil mass plot, the minimum value of runoff was observed in case of URDP and maximum was for ARDP at 4% land slope while at 8% land slope the minimum value of runoff was observed in case of IRDP and maximum was for URDP. Similarly, the minimum average sediment concentration in this case was observed as 1236.66 PPM in case of DRDP and the maximum value of sediment concentration was observed as 1483.33 PPM in case of URDP at 4% land slope. At 8% land slope, the minimum and maximum values of runoff were observed in case of IRDP & URDP rainfall pattern while the minimum and maximum values of sediment concentration were observed in case of DRDP and ARDP rainfall pattern respectively. The observations and analysis of the findings clearly indicated that in case of runoff, plot with below soil bio mass provided better reduction as compared to above soil bio mass plot for every rainfall distribution pattern. In case of sediment, however, the situation was not that clear as in case of IRDP and DRDP below soil bio mass plot provided better reduction in sediment concentration but n case of IRDP and ARDP, above soil bio mass plots had an edge over below soil bio mass plot in sediment outflow control. Observed values of total runoff indicated that the highest runoff rate occurred in case of land without any treatment under URDP while the lowest runoff rate occurred in case of lands treated with across the slope. It was also observed that the runoff rate got reduced by more than 50 in case of lands treated with across the slope as compared to lands without any treatment under every rainfall distribution pattern. It was also seen that the across the slope furrow treatment produced lesser runoff rate by 25.925%, 20.833%, 18.309% and 17.46% as compared to along the slope furrow treatment at 4% land slope under URDP, ARDP, DRDP and IRDP respectively.
  • Thumbnail Image
    ThesisItemOpen Access
    Comparative assessment of different geostatistical approaches for spatial interpolation of annual rainfall
    (G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2021-02) Verma, Shikha; Singh, Praveen Vikram
    Rainfall is an essential component and acts as primary input for hydrological modelling. The availability of reliable data is necessarily important to obtain the maximum benefit from hydrological analysis. The rainfall in rajasthan is so irregular and unpredictable spatially as well as temporally. The measurement of rainfall is very important however it is not practically possible to measure at each and every point. In such situations, rainfall measurements are typically available at a finite number of rain gauges therefore, determination of rainfall at various ungauged stations needs spatial interpolation to assess the spatial variability of the region. The analysis was done over annual rainfall of rajasthan having 253 raingauging stations for a period of 40 years (1980–2019). The present study was an attempt to analyze and compare the performance of different geostatistical spatial interpolation techniques, univariate, Ordinary Kriging (OK), and multivariate, Simple Co-kriging (SCK) and Ordinary Co-kriging (OCK), to interpolate the annual rainfall. In both the techniques, spherical, circular and Gaussian models were used to find the best-fitted semivariogram for rainfall prediction purpose. The nugget-sill ratio was determined for all the nine models to decide the best fit model. The statistical analysis of nugget-sill ratio for univariate and multivariate geostatistical analysis revealed that the ordinary kriging (OK-Circular) and ordinary cokriging (OCK-Spherical) was followed the least standard deviation as 0.1121 and 0.1051, respectively in the dataset. The cross-validation results were depicted the overall comparative evaluation of the selected models in which OCK-Spherical outperformed over OK-Circular by the consideration of different statistical parameters. For OK-Circular, the value of ME, RMSE, MSDE, RMSSDE and ASE were found to be 0.6525, 210.1545, 0.0035, 1.0306 and 204.4955 and for the validation of ordinary co-kriging OCK-Spherical these statistical parameter values were found as 0.3221, 210.3274, 0.0023, 1.0367 and 203.6121, respectively. Finally, the study concluded that the incorporation of elevation as a secondary variable with rainfall, increases the accuracy of estimation of spatial continuity of rainfall at ungauged locations irrespective of its correlation with the rainfall. However, both the selected models performed well for the study area. Statistically, OCK-Spherical worked better than OK-Circular method of interpolation.