Faculty Publications
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Item [No abstract available](Systems analysis of tank irrigation: I. Crop staggering) Mayya, S.G.; Prasad, R.1991Item Semi Impervious Subsurface Barrier for Water Conservation in Lateritic Formations(Springer India sanjiv.goswami@springer.co.in, 2014) Udayakumar, G.; Mayya, S.G.The coastal districts of Karnataka in west coast of India experience acute shortage of drinking water during dry season in spite of heavy monsoon rains. Though sufficient recharge of ground water takes place, depletion of water table is very quick, once the rain recedes. It is mainly attributed to the presence of porous and highly permeable laterites and lateritic soils. The hydraulic conductivity of these soils varies in the range of 10?4 to 10?5 cm/s. The conventional water harvesting methods fail to solve the problem. It is necessary to explore innovative method to regulate the lateral subsurface flow and maintain a high water table over a prolonged period of time. The present work is an attempt to explore the possibility of using semi impervious Subsurface Barrier (SSB) to regulate and control the lateral flow of water in the unconfined aquifer in lateritic formations. Appropriate barrier material is arrived at using the locally available soil and the required properties are established. A SSB is built in a suitable location in an identified microwatershed using lateritic soil and the composite soil prepared by mixing requisite percentage of lateritic soil and clay. The hydraulic conductivity of these soils is maintained in the range of 10?6 to 10?7 cm/s so as to behave as semi impervious. The performance analysis is carried out by observing water levels in selected open observation wells before and after the construction of the barrier. The results have shown the successful performance of SSB in maintaining a high water table over a prolonged period of time during summer months, both in u/s and d/s of the barrier. © 2014, The Institution of Engineers (India).Item Development of operation policy for dry season reservoirs in tropical partially gauged river basins(Taylor and Francis Ltd., 2024) Gowda, C.C.; Mahesha, A.; Mayya, S.G.The present investigations focus on developing an appropriate model for streamflow generation of a partially gauged basin and the operation of small storage in a tropical, seasonal river basin. The small storages created through the vented dams effectively conserve and sustain the water resources for the lean season. Hence, it is pertinent to develop streamflow models to derive streamflow series at the vented dam locations. In the present investigation, streamflow modelling was attempted using response surface and neural network models in a first of its kind. Out of them, the Response Surface Box Behnken model was found to be most efficient in generating streamflow, with Nash Sutcliff's efficiency above 0.617. Further, it is also essential to operate these small storages to maintain a sustainable, ecological flow in the river course. The operation policy for seasonal storage like vented dams is yet to be reported in the literature. The present work uses reservoir simulation and multi-objective optimisation to derive such storages operation policy through hedging operations, with modified shortage index and mean event deficit as objectives. The performance indicators evaluated the operation policy for eight vented dams of the basin. The results illustrate that vented dams indicate shortages while satisfying the respective demands. The results demonstrate that hedging improves the reservoir's performance by reducing the mean event deficit of 0.268–0.044 Mm3 before and after hedging. The frequency and intensity of shortages were also reduced through hedging for the tropical, seasonal river basins. © 2022 International Association for Hydro-Environment Engineering and Research.