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Subject: Soil and Water Engineering × Author: KAU × End date: 2014 × Start date: 2014 × Type: Thesis × Thesis Type: M.Tech. ×
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    ThesisItemOpen Access
    Soil erosion studies under simulated rainfall conditions in a lateritic terrain
    (Department of Land and Water Resources and Conservation Engineering, Kelappaji College of Agricultural Engineering and Technology, Tavanur, 2014) Praveena, K K; KAU; Kurien, E K
    Soil erosion IS a complex phenomenon involving the detachment and transport of soil particles, storage and runoff of rainwater and infiltration. Soil erosion depends on several factors such as climate, soil type, topography, cropping and land management practices, the antecedent conditions and the size of the area under consideration. The present study was carried out in the lateritic terrain of KCAET campus, Tavanur, Malappuram District. This study was aimed at developing a rainfall simulator and studying the performance of the developed rainfall simulator, the effect of rainfall on soil loss, the effect of rainfall on runoff and developing a soil erosion model. A rainfall simulator was fabricated to study the erosion processes. Rainbird 12115118 Van Pop up sprinkler heads were used as the drop formers. The simulator evaluated for its performance. The soil was reddish brown and belonged to the textural class of sandy loam. It belonged to the Naduvattom series. The experimental set up consisted of three units viz., the runoff plot, the rainfall simulator and the runoff-sediment collection unit. Twelve runoff plots with twelve different slopes of 1.5, 2.0, 2.6, 3.0, 3.2, 4.0, 5.0, 6.0, 9.0, 10, 12 and 13 per cent in different locations, each plot with a size of2 x 1.5 m were prepared. The fabricated rainfall simulator could produce rainfall intensities varying from 8.16 to 8.80 ern/h. The uniformity of rainfall varied from 89.01 to 92.70 per cent and the average drop size varied from 1.5 to 2.8 mm. A relationship between supply pressure and intensity of rainfall as well as intensity and uniformity of rainfall was developed. Studies were conducted on soil loss and runoff at different land slopes under simulated rainfall conditions. The soil loss and runoff was found to increase with increase in rainfall intensity and land slopes and there were no much variations on runoff and soil loss at 6 to 10 per cent land slopes. A linear multiple regression analysis and 3D surface plot analysis was used to incorporate slope and rainfall intensities into a single prediction equation of soil loss and runoff using SPSS software and MATLAB package. The linear equations developed by the regression analysis are as follows: Q = 38.9451 - 11.606 S - 126.391 E = 124.356 1 - 0.807 S -951.420 (R2 = 0.649) (R 2 = 0.307) The quadratic equations developed by the 3D surface plot analysis are as follows: Q = 130.8 - 28.72 S + 48.12 1 + 2.11 S2 - 1.544 S 1 E = - 647.4 - 49.261 + 86.94 S - 0.3206 12 +6.296 S I As the variants explained were satisfactory enough to explain the runoff and soil loss, it may be concluded that the causative factors namely slope and intensity are bearing directive impact on soil erosion. A canonical analysis was worked out to determine the effect on runoff and soil loss by the vector of parameters u ing slope and intensity. Canonical R was computed and the same was 0.82034 and it is significant at 1 per cent level. Hence it may be concluded that the vector of process 'including slope and intensity as parameters together navigates the ultimate impact namely runoff and soil loss.
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    ThesisItemOpen Access
    Development of a filter system for roof water harvesting
    (Department of Land and Water Resources and Conservation Engineering, Kelappaji College of Agricultural Engineering and Technology, Tavanur, 2014) Shijila, Erikottil; KAU; Sathian, K K
    This thesis work was undertaken to study the performance of modified mesh filter under rainfall. The mesh filter was modified with two other filters such as sand and charcoal filter and their combination study was conducted on artificial rainwater and evaluated the quality of filtered water. The two filters are fabricated with naturally available material such as above 1 mm size coarse sand and small pieces of burned coconut shell. These materials are freely available from surroundings and each material was filled in each PVC pipes of 25 cm length. From the first study four buildings are selected in the campus have different impurity levels that because of rain fall events, purposes or constructed material. It was found that there are small variations in the quality of harvested water but after filtration all results are same because filter was not depends on the roofing material and impurity level. The quality parameter like pH of the rainwater harvested after the filtration with mesh filter for all roofs met the USEPA secondary drinking water standard range of 6.5-8.5. The electrical conductivity, turbidity and suspended solids are also met the drinking water standards by WHO and the calculated average filter efficiency of mesh filter was 81.3 %. From the filter combination study the quality parameter such as pH, electrical conductivity, turbidity and suspended .,olids also examined through water quality analyzer of collected samples. As per the BIS 10500 of 2004 and WHO all the results are in the permissible range. The BOD test result was ranging from 44 to 92 mg/l and compared to inflow the filtered water has drastic reduction in the values. From the coliform test it was cleared that there were no colifirms (011 OOml) in the filtered water after 24 hour incubation period where as in inflow water coliforms were detected. It was found that there is a marked reductio'. .n the concentration of impurities, The reduction in im urities ranges from 84 to 86 % and the charcoal tilter has highest filtration rate of 9.42 m3/minlm2 compared to others. The results clearly. revealed that combined filters remove the impurities in a more efficient manner than of the mesh filter developed earlier. There is only minor difference between the both filters. The results clearly revealed that combined filters remove the impurities in a mo: e efficient manner than of the mesh filter developed earler. There is only minor difference between the both filters.