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  • Jan, 2013
    Volume - 33, No. - 1
    SCOUR PROTECTION BY A SLOT THROUGH A MODEL BRIDGE PIER
    Baldev Setia and Upain Kumar Bhatia

    A laboratory investigation has been carried out to determine the scour depth reduction for cylindrical pier models of 80mm and 82mm diameter provided with rectangular slots through them and located in two separate water flumes A and B with sediment 1...

1969 Dec

Issue (Volume No. 33, Number 1)

SCOUR PROTECTION BY A SLOT THROUGH A MODEL BRIDGE PIER

A laboratory investigation has been carried out to determine the scour depth reduction for cylindrical pier models of 80mm and 82mm diameter provided with rectangular slots through them and located in two separate water flumes A and B with sediment 1 (d50=0.16mm, ?g = 1.38) bed and sediment 2 (d50=0.60mm, ?g = 1.72) bed respectively. The types of slots investigated upon were: 0? to 180? (Parallel slot), 0? to +120? (Y-slot), 0? to +90? (T-slot) and 0? to +45? (Sigma slot). Various parameters varied included height of slot, bifurcation angle and some modifications of the slot. Results suggest that a parallel slot and a Y-slot with optimum dimensions as 0.25D wide, 1D above and 0.75D below the sediment bed are able to reduce scour by 50% and 40% respectively. Some better found results were investigated on an oblong pier and in combination with a group of piles as well.

by Baldev Setia and Upain Kumar Bhatia
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  • Jan, 2013
    Volume - 33, No. - 1
    EXPERIMENTAL VERIFICATION OF THE EFFECT OF SLOPE ON RUNOFF AND CURVE NUMBERS
    Anubhav Chaudhary , S.K. Mishra and Ashish Pandey

    The present study investigates experimentally the effect of watershed (i.e. field plot of 22mx5m) slope on rainfall-generated runoff and resulting curve numbers (CN) for a given soil (Hydrologic Soil Group C) and land use of sugarcane. As expected, t...

1969 Dec

Issue (Volume No. 33, Number 1)

EXPERIMENTAL VERIFICATION OF THE EFFECT OF SLOPE ON RUNOFF AND CURVE NUMBERS

The present study investigates experimentally the effect of watershed (i.e. field plot of 22mx5m) slope on rainfall-generated runoff and resulting curve numbers (CN) for a given soil (Hydrologic Soil Group C) and land use of sugarcane. As expected, the plot of 5% slope yielded the largest runoff and, in turn, CN compared to those due to the plots of 3% and 1% grades, for the same rainfall, soil, and land use. The derived CN values are fairly close to those from NEH-4 CN-values, supporting the applicability of NEH-4 CN values to Indian watersheds.

by Anubhav Chaudhary , S.K. Mishra and Ashish Pandey
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1969 Dec

Issue (Volume No. 33, Number 1)

ASSESSMENT OF AGRICULTURAL DROUGHT IN 2006 AMAN SEASON AND ITS MANAGEMENT BY THE FARMERS: A CASE STUDY IN RAJSHAHI DISTRICT (BANGLADESH)

Although the droughts are common in the north-west region of the country, especially in the Barind Tract, not much is known about the mitigation measures adopted by the farmers. This study was accomplished with a view to assess the drought of T. Aman season of 2006 and farmers? management practices of drought alleviation at Godagari Upazila in Rajshahi district. The time and extent of drought was calculated by using the water balance and relative water supply methods. The probability analysis of rainfall and crop water requirement was carried out by Gamma distribution. Drought affected yield was estimated by using crop production function. A farmers? survey was conducted to gain information on drought affected yields, farmers? management practices of drought alleviation and related socio-economic issues. From the water balance analysis it was found that three droughts occurred during the T. Aman season of 2006: one drought of six days duration and another of four days duration during vegetative and reproductive stages, respectively and one drought of sixteen days duration during the ripening stage. The average values of RWS were 0.60 in vegetative stage, 0.66 in reproductive stage and 0 in ripening stage. Both the analyses showed that severe drought occurred during the ripening stage of T. Aman in 2006. From probability analysis, it was observed that the probability of rainfall that occurred during the T. Aman season of 2006 is about 20% (once in about five years). From the farmers? survey, it was revealed that during 2006, 75% of the farmers used supplementary irrigation for T. Aman production. The average yield was 4.05 M. ton/ha for the farmers who provided supplementary irrigation and drought affected yield was 1.64 M. ton/ha. The drought affected yield calculated from crop production function was 1.65 M. ton/ha. Actual drought affected area during 2006 T. Aman season was estimated as about 13% of the Aman cultivated area. The benefit-cost ratio (BCR) of supplementary irrigation from surface water and ground water were 4.10 and 5.88, respectively. The farmers? survey showed that supplementary irrigation was the only socially acceptable management practice of drought alleviation in the study area. The study reveled that due to the application of supplementary irrigation, droughts do not severely affect the T. Aman yield.

by Mst. Irin Parvin and Abul Fazal M. Saleh
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  • Jan, 2013
    Volume - 33, No. - 1
    ESTIMATION OF EVAPOTRANSPIRATION WITH ANN TECHNIQUE
    M. U. Kale , M. B. Nagdeve and S. J. Bagade

    To identify the best alternative method to estimate reference evapotranspiration (ETo), performances of various ANN architectures and two climate based methods namely Penman? Monteith (P-M) (FAO-56) and Hargreaves-Samani (H-S) model, were compared wi...

1969 Dec

Issue (Volume No. 33, Number 1)

ESTIMATION OF EVAPOTRANSPIRATION WITH ANN TECHNIQUE

To identify the best alternative method to estimate reference evapotranspiration (ETo), performances of various ANN architectures and two climate based methods namely Penman? Monteith (P-M) (FAO-56) and Hargreaves-Samani (H-S) model, were compared with FAO-24 Pan evaporation model. Practical based pan evaporation method (FAO-24) was taken as standard method. The ANN architectures formulated using varied input combinations of climatic variables, were trained using backpropagation algorithm i.e. Levenberg-Marquardt with sigmoid function. Performances of these methods were evaluated using the statistical indices i.e. mean standard error (MSE), root mean square error (RMSE) and the coefficient of determination (r). The results confirmed that when all climatic data is available, Penman-Monteith method is the best indirect method for daily ETo estimation. The ANN (2-2-1; input parameter - air temperature and wind speed only) with an r of 0.94 and RMSE of 0.48 mm day-1 estimated fairly accurate ETo. The climate based Hargreaves-Samani model overestimated the ETo by about 112%. Hence, ANN (2-2-1) topology should be used to estimate fairly accurate ETo when data pertaining to climatic parameters is insufficient to apply standard ETo estimation methods.

by M. U. Kale , M. B. Nagdeve and S. J. Bagade
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  • Jan, 2013
    Volume - 33, No. - 1
    PLANNING FOR OPTIMUM USE OF WATER RESOURCES OF MRP COMPLEX USING MIKE BASIN
    S.K. Jaiswal , M. K. Verma and Mohan Gupta

    This paper deals with the application of simulation software ?MIKE BASIN? (2009) for optimum utilization of water resources of MRP Complex. Mahanadi Reservoir Project (MRP) Complex is a multipurpose multi-reservoir system. It consists of Mahanadi bas...

1969 Dec

Issue (Volume No. 33, Number 1)

PLANNING FOR OPTIMUM USE OF WATER RESOURCES OF MRP COMPLEX USING MIKE BASIN

This paper deals with the application of simulation software ?MIKE BASIN? (2009) for optimum utilization of water resources of MRP Complex. Mahanadi Reservoir Project (MRP) Complex is a multipurpose multi-reservoir system. It consists of Mahanadi basin and Pairi basin. This project comprises of four reservoirs. There is inter-basin transfer of water from Sondur reservoir in Pairi basin to Dudhawa reservoir in Mahanadi basin through a feeder canal. MIKE BASIN has extensive reservoir modeling capabilities, and accommodate multi-purpose reservoirs and multiple reservoir systems. The philosophy behind MIKE BASIN is to keep modeling simple and intuitive, yet provide in-depth insight for planning and management. In this paper, an attempt has been made to decide the strategies for optimum use of water available in the reservoirs of MRP Complex. There are three possible ways of supplying water from the two upstream reservoirs to the Ravishankar reservoir. These three ways of supplying water has been simulated in MIKE BASIN and designated as three models. The simulation has been run for twenty one years (1975 to 1995) historical data. To check the efficiency of models the annual deficit between demand and supply has been computed for each model. The results of these three models have been compared with the results of earlier reported optimization model. The total deficit for twenty one years was found minimum in the first model hence this is the efficient model. First Model is then run for recent data (1996-2008). The model is working well for the recent data (1996-2008).

by S.K. Jaiswal , M. K. Verma and Mohan Gupta
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1969 Dec

Issue (Volume No. 33, Number 1)

SUITABILITY OF DISTRIBUTED SCS-CN MODEL FOR NARMADA BASIN: A CASE STUDY OF URI RIVER SUB-BASIN

Estimation of watershed runoff accurately has been a challenge for water resource managers and planner especially for large river basins. Inflow forecasting in the series of multipurpose reservoirs constructed in Narmada river basin shall be useful for maximization of hydropower generation to its optimum capacity. The accuracy in predicting the surface runoff becomes more imperative in case of large watersheds like river Narmada basin. In the present study, alternate options of spatially distributed SCS-CN model and modified SCS-CN model have been applied in the Uri river basin. The daily runoff has been computed under three conditions; (i) by considering area weighted average CN and rainfall, (ii) spatially distributed CN and rainfall with Ia/S ration as 0.2 and (iii) considering average CN and rainfall with Ia/S ratio as 0.05. The analysis shows that the computed runoff are more close to the observed runoff, if runoff is computed by considering area weighted average CN and average rainfall in lower Narmada river basin.

by T. R. Nayak and S. M. Narulkar
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