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1990 - 199912010 - 20201
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Subject: Irrigation and Drainage Engineering × Thesis Type: M.Sc ×
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    ThesisItemOpen Access
    Flood frequency analysis and modelling of flood using HEC-HMS for a river basin: a case study
    (Department of Irrigation and Drainage Engineering, Kelappaji Collge of Agricultural Engineering and Technology, Tavanur, 2020) Riyola, George; KAU; Asha, Joseph
    Meenachil river basin, located in southern part of Kerala, is an area frequently liable to flood. The area is predominant with agricultural land and falls under the tropical humid zone, where water resources planning and management is necessary for irrigation scheduling, flood control and design of various engineering structures. In view of the importance of water resources management especially in this humid region, it is necessary to understand the rainfall-runoff relationship along with its land characteristics. HEC-HMS model which is widely used rainfall-runoff modelling was chosen for the simulation of watershed responses and generation of flood hydrographs of Meenachil sub basin. The simulated runoff is useful for well-planned programmes in water resource management and future prediction of runoff for flood mitigation strategies in the catchment. Hence, an attempt was made to conduct flood frequency analysis for predicting the magnitude of flood for different return periods and to calibrate and validate the HEC-HMS model for simulating the flood hydrographs of Meenachil sub basin. Flood frequency analysis was carried out using annual maximum discharge data for 34 years (1985-2018) using HEC-SSP software. The HEC-HMS model for the sub basin was developed using SCS-UH, SCS-CN and Muskingum methods to find out the loss rate, runoff transformation and routing of flood respectively. Flood frequency analysis clearly indicated the good capability of the Gumbel and Log-Pearson Type III distribution function to predict flood magnitudes of the river flow in the sub basin of Meenachil River. Test statistic values of Chi-Square and Kolmogorov-Smirnov test showed the best fit of both the distributions for the basin. HEC-HMS model of the sub basin was developed with good accuracy. The performance indices of the model NSE and R² were obtained above 0.7. The Error in Peak Flow and Error in Volume were figured below 20% where as RSR was found 0.5 and below. All these values indicated satisfactory performance of HEC-HMS model simulation both in calibration and validation. The close agreement of simulated stream flow and observed stream flow indicated that the model was able to simulate flood hydrograph and present credible results for the sub basin.
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    ThesisItemOpen Access
    Quantitative analysis of runoff parameters in selected river basins of Kerala
    (Department of Irrigation and Drainage Engineering, Kelappaji College of Agricultural Engineering and Technology, Tavanur, 1990) JJayasree, S; KAU; John Thomas, K
    The evolution of a drainage basin is the result of the flow of mass and energy and the resistance of topographical surface. Precipitation is the major source of matter and solar radiation, the source of energy. The stream flow is a function of geomorphological and hydrological factors of the river basin. The objectives of this study were to make a quantitative analysis of the effects of geomorphological and climatic factors on the stream flow and to study the inter – relationships between these factors. The selected river basins were Chaliyar and Kabbani. The specific objective was to express stream flow in terms of morphological factors and rainfall. The river basin was divided in to sub basin, each of which contains a rivergauge station. Morphological factors were measured from the map. Monthly rainfall from all the raingauge stations were collected and the arithmetical average for each sub-basin was computed. The monthly stream flow was also collected. It was found that the morphological factors were interrelated. The number of stream segments of successive order form a decreasing geometric progression whereas the length of stream segments of successive orders form an increasing geometric progression. Confluence ratio is inversely related to stream flow. Elongation and drainage area are highly correlated. A larger value for the confluence ratio indicates a more elongated basin and a lower flood peak. The sub - basins are similar to the form of a rectangle. Area and elongation are the morphological parameters strongly influencing the stream flow. Drainage density and stream frequency are highly correlated. Drainage density gets altered by the land use, vegetal cover, deforestation and urbanization. Drainage density also affect stream flow. Finally, the expressions for drainage area in terms of the main stream length, drainage density in terms of stream frequency and average monthly stream flow contributed by unit area in terms of the average monthly rainfall were obtained. The data used for the final equation was inadequate. The equation may be improved, by increasing the number of rivergauge stations and providing more representative raingauge stations.