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Subject: Soil and Water Engineering × End date: 2014 × Start date: 2014 × Type: Thesis × Thesis Type: M.Sc ×
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    ThesisItemOpen Access
    Development of a Water Distribution Model for Warabandi System
    (Punjab Agricultural University Ludhiana, 2014) Bagchi, Argha; Siag, Mukesh
    ABSTRACT A study of warabandi distribution has been done taking data from the Punjab State Irrigation Department for the watercourse number 79000R and 62740L on Bajidpur and Rookanpura minors respectively, located in Abohar Tehsil in South-West Punjab. The Irrigation Department is distributing the water under warabandi system without taking into account seepage losses along the watercourse. Seepage losses were calculated for both the lined and unlined section of the watercourses by ponding test. Seepage losses were considerable, especially in the unlined section. In this study, a computer model in C++ language has been made to find the water distribution time among farmers by accounting for seepage losses along the watercourse. The model gave water distribution similar to that given by Irrigation Department if no seepage loss is taken, whereas there is considerable redistribution if seepage losses are accounted for. The distribution time of farmers near the outlet is reduced, whereas for farmers at the tail of the watercourse, especially with unlined section, the time increase, thus indicating proper compensation for seepage. Accounting for seepage losses ensures better equitable distribution of the irrigation water among the farmers. A comparison was also done between actual filling and drainage times taken for the watercourses, as mutually agreed between farmers and the Irrigation Department, and estimated times of filling and drainage depending on discharge of outlet and size of watercourse. There is some variation in the filling and drainage time taken and that estimated, with drainage time taken being considerably less than estimated.
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    ThesisItemOpen Access
    Simulating rainfall change effects on runoff and soil erosion in submontane punjab
    (Punjab Agricultural University, Ludhiana, 2014) Mandeep Singh; Hadda, M. S.
    Complete understanding of the simulation studies is important for management of soil erosion and maintaining maximum level of agricultural production in submontane Punjab. In the area, the information is available on the accurate records of rainfall which cover sufficient duration of rainy season to enable accurate assessment of runoff and soil erosion. Therefore, the models that are capable of utilizing the rainfall records and soil moisture retention data to simulate runoff and soil erosion will be of great utility. In this connection, the SCS-CN approach has been widely used at different places over the globe to estimate runoff and relating it with soil erosion to arrive at conclusive results. Keeping these points in view, therefore, the present study was planned with the following objectives such as i) to determine the initial abstraction ratio (Ia/S) in an experimental Patiala-Ki-Rao watershed by analysing measured rainfall-runoff events; ii) to compare the performance of the traditional and modified Ia/S values with observed rainfall-runoff data; iii) to assess potential changes in runoff and soil erosion with respect to long term changes in rainfall patterns in submontane region. The present study was conducted to simulate surface daily runoff depth and event wise soil loss for two gauged micro-watersheds I and II of Patiala-Ki-Rao, District Roopnagar. Afforestation and fencing was applied to micro-watershed I and only fencing was applied to micro-watershed II. The SCS-CN method using Ia/S=0.2 and Ia/S=0.05 was used to simulate surface runoff depth and Modified Universal Soil Loss Equation (MUSLE) and Revised Modified Universal Soil Loss Equation (RMUSLE) were used to simulate event wise soil loss for total 42 rainstorms for the six years as 1983, 1984, 1986, 1987, 1991 and 1994 in the watersheds. The computed daily runoff depth (min to max) with Ia/S=0.2 showed higher coefficient of variation (CV%=128.6 to 21.2) than that with Ia/S=0.05 (CV%=59.1 to 17.1). Daily runoff depth was better simulated with Ia/S=0.05 than that with Ia/S=0.2 for both the micro-watersheds as indicated by their higher R2 and low RMSE obtained between simulated daily runoff depth and historical daily runoff depth (R2=0.90 with Ia/S=0.05; R2=0.78 with Ia/S=0.2 and RMSE=6.5 with Ia/S=0.05; RMSE=19.5 with Ia/S=0.2). The RMUSLE performed better than that MUSLE for both the micro-watersheds as indicated by lower per cent error and higher R2 obtained between simulated event wise sediment yield and historical event wise sediment yield .The per cent error varied from -3.5 to -27.6 for RMUSLE than that with MUSLE from -4.6 to -26.9 per cent in micro-watershed I. In the same watershed, the R2 obtained for RMUSLE (R2=0.99) was higher than that with MUSLE (R2=0.97) in simulating the sediment yield. However, the per cent error varied from +7.1 to -24.9 for RMUSLE than that from +5.4 to -28.3 per cent for MUSLE for micro-watershed II. In the same watershed, the higher R2 was obtained with RMUSLE (R2=0.96) than that with MUSLE (R2=0.87). Also, there was potential increment in runoff and sediment yield with increase in product of rainfall-runoff factor. However, the simulated runoff and soil erosion were better predicted at low to moderate rainfall amounts in the micro-watersheds. Results of the study suggests that there is need to compare the performance of the new lumped models proposed in literature based on soil conservation service curve number and variable source area approach to simulate runoff and sediment yield at higher rainfall amounts.