Browsing by Author "Anu Varughese"

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Assessment of saline water intrusion from Ponnani to Tavanur along the course of river Bharathapuzha
(Department of Soil and Water Conservation Engineering, Kelappaji College of Agricultural Engineering and Technology, Tavanur, 2022-10-27) Hasna Ameena, P O.; Anu Varughese
The study on „Assessment of saline water intrusion from Ponnani to Tavanur along the course of river Bharathapuzha‟ was done with the objectives to prepare the base map and landuse map of the study area, to develop a groundwater flow model, and to understand the saline water intrusion in coastal aquifers of Ponnani region. The study area involves part of Tavanur and Ponnani regions of Bharathapuzha river basin having geographical location of 10.76° to 10.85° North latitude and 75.88° to 76° East longitude, which comprises of about 50 km2 area.For modelling groundwater resources and salt movement, visual MODFLOW is recognized as a useful tool. In this study, Visual MODFLOW 2.8.1 integrated with MT3D software was used for ground water modelling and modelling saline water intrusion.The land use map of the area was prepared in ERDAS Imagine software using supervised classification. The area was divided into 50 columns and 50 rows (2500 cells).Water level and water quality data of observation wells were measured from the field and secondary data obtained from the wells of Central Water Commission in the study area were used as input to the model. In Ponnani and Purathur regions, salinity and electrical conductivity was also found to be higher than the standard limits for drinking water. The salinity level in the pre-monsoon period is even higher (1500 ppm) than the recommended limits for irrigation. Data on hydrogeological parameters and aquifer properties needed as the input for the modelwere also collected from different sources. In subsurface research, the use of contaminant transport models was fully supported in the context of ground water quality.The model was developed and calibrated with 7 years data (2012 to 2018) and validated with 3 years data (2019 to 2021). After validation, the model was used for prediction. Prediction was done for 10 years by increasing the pumping rate by 5, 10 and 15 per cent of pumping rate during the validation period (2021). It was observed that the saline water intrusion is present in the coastal stretch of Padinjarekkara,Purathur and Ponnani regions of Bharathapuzha river basinwhich extends along the coast from the northern boundary of Bharathapuzha river basin. It was also predicted from the model study that the saline water intrusion reaches to a lateral distance of 4.8 km to 5.5 km from the coast along the course of river. In the current climate change scenario, global warming and the related sea level rise pose a serious concern and are a major contributor to saline water intrusion into coastal freshwater aquifers. The activities carried out in the river basin that damage the area and facilitate the movement of contaminants including sand mining from Bharathapuzha and various types of developmental activity like construction, small-scale industry, and agriculture along the coast accelerates the saline water intrusion in this area.To minimize salt water intrusion, groundwater pumping in coastal areas (up to 5.5 km from the coast) need to be restricted
Climate change impact on operation policy and performance indices of a reservoir using machine learning techniques
(Department of Soil and Water Conservation Engineering Kelappaji College of Agricultural Engineering and Technology, 2025-11-22) Vinnakota Yesubabu; Anu Varughese
Water resource systems play a major role in human wellbeing. The hydrologic changes resulting from climate change will affect the planning, design, and operation of water resource systems. Developing water schemes based on present conditions without considering possible future changes could increase water resource pressure in the future period. Therefore, it is of utmost importance to consider these changes in the future design and management of water supply systems. To comprehend the impact of climate change on water resource management, a comprehensive modelling framework that considered both hydrological responses and reservoir operation was indispensable. In this regard, Malampuzha reservoir system in Palakkad district of Kerala was selected to evaluate the impact of climate change on reservoir and its performance. To select the suitable climate model for the study, the performance of 15 CMIP6 GCMs in precipitation, maximum and minimum temperature was compared to the observed data of Malampuzha for the period 1990-2014 with the help of Compromise Programming (CP) that involves metrics such as R2, PBIAS, NSE and NRMSE. The results of the CP analyses of the statistical metrics suggests that CNRM-CN6-1 model for precipitation and MRI-ESM2-0 model for maximum and minimum temperature are the suitable models for Malampuzha region. Different bias correction techniques were applied to improve the raw predictions of GCMs. Power Transformation (PT) for precipitation and Variance Scaling (VS) technique for temperature has shown superiority over other techniques. Three future scenarios were considered in this study from CMIP6 Shared Socioeconomic Pathways (SSP126, SSP245 and SSP585). Selected bias correction techniques were applied to the future period to get bias corrected future climate variables. Rainfall-runoff modelling was chosen to predict reservoir inflow. Three hydrological models (IHACRES, SWAT and HECHMS) and Machine Learning (ML) models such as ANN, SVM, RF, and Wavelet coupled models were compared and Wavelet coupled RF (WRF) model was selected because of its greater accuracy and was used to simulate future reservoir inflow under different SSPs. CROPWAT model was used to estimate the irrigation water requirement for baseline and future periods. Land use change analysis of Malampuzha reservoir command area was done with the help of MOLUSE plugin of QGIS. Optimization program was developed by considering all the necessary constraints with the objective of minimizing squared relative deficiency in water allocation. Optimal water allocation was derived from the developed optimization technique using genetic algorithm for baseline and future periods. Reservoir performance indices such as Reliability, Vulnerability, resiliency and sustainability were calculated and compared for both timelines. Climate change impact on reservoir performance is evaluated. Selected GCM models predicted an increase in average annual maximum temperature (from 0.23oC in near future to 3.26oC in far future), an increase in average annual minimum temperature (from 0.62oC in near future to 3.12oC in far future) and decrease in average annual precipitation (2.73% in near future to 10.89% in far future) in the future compared with the base period. The LULC changes indicate a shift towards urbanization and plantation expansion, with a concurrent decline in agricultural lands (2425 ha (14%) reduction by the end of the century) and water bodies. Because of an increase in crop water demand of 11.7% and decrease in reservoir inflow of 27.3%, the amount of water allocation under optimal reservoir management conditions was less than the demand. The command area water demand will not be met by the reservoir for far futures of SSP245 and SSP585 scenarios because of more increase in temperature (3.26oC) and erratic behavior of precipitation which indicates the impact of climate change. A suitable optimization technique using genetic algorithm was developed which can be used for deriving the best operation policy for the Malampuzha reservoir in future. The observed decline in reliability and resiliency along with a notable increase in vulnerability from 0.028% to 9.47%, emphasizes the substantial challenges that climate change imposes on reservoir operation. These findings highlight the urgent requirement of climate-resilient management strategies to ensure the long-term sustainability of reservoir in the far future.
Development and performance evaluation of vertical farming structures in rainshelter
(Department of Irrigation and Drainage Engineering, Kelappaji College of Agricultural Engineering and Technology, Tavanur, 2022) Gopika, P; Anu Varughese
A study was conducted to develop a vertical farming structure suitable for rainshelters for homestead cultivation of Kerala and to evaluate the performance of the developed structure. The newly designed and fabricated Vertical Farming Structure (VFS I) was compared with two existing structures, viz, VFS II and VFS III. Amaranthus of CO-1 variety was selected for the study. Combination of Sand: Soil: Cowdung: Vermicompost in the ratio 1: ½: 1: ½ respectively on volume basis was selected as the growing media. Irrigation was provided through drip irrigation. The performance of the vertical farming structures was compared by assessing the climatic parameters (temperature, RH, light intensity and PAR) and biometric observations (height and number of branches) and yield. Maximum temperature (37.28°C) was recorded during 1:00 PM and lower temperature (24.1°C) was recorded during early morning hours. Higher relative humidity (98.9%) was recorded during early morning hours and lower relative humidity (50.59%) was recorded during afternoon hours. Light intensity and PAR were maximum in VFS I (49000 lux and 1032 µmol m-2 s-1) followed by VFS II and VFS III respectively. Statistical analysis was done by twoway Analysis of Variance (ANOVA) with replications using SPSS 16.0. The results from statistical analysis showed that the light intensity and PAR at 8:00 AM, 1:00 PM and yield per plant showed a significant difference between the structures and tiers individually and also in combination at 5% level of significance. Light intensity and PAR at 5:00 PM, height and number of branches significantly varied between structure and tier individually. Maximum B-C ratio of 1.33 was obtained for VFS I, followed by 1.19 and 1.13 for VFS II and VFS III respectively. The positive values of NPW in all the three cases indicated that the project is viable. The overall results of the study revealed that the VFS I showed better performance in all aspects compared to VFS II and VFS III. The study recommended rainshelter cultivation of vegetables with facility for utilising vertical space using the vertical farming structure and drip irrigation. The developed structure is suitable for increasing the production from the homesteads of Kerala.
Effect of soil solarization using ldpemulch on moisture conservation and soil temperature variation
(Department of Land and Water Resources and Conservation Engineering, Kelappaji College of Agricultural Engineering and Technology, Tavanur, 1997) Anu Varughese; John Thomas, K
Soil solarization is based on mulching the soil surface with transparent polyethylene sheets which capture the solar radiation and thus heat the soil to a level lethal for various pests. Solarization is useful in the control of weeds and also helps in moisture conservation. To some extent this can satisfy the demand of water for pre sowing irrigation during the summer months by conserving the moisture in the soil. In the experiment two types of polyethylene sheets (0.10 mm and 0.05 mm) were used and three durations of solarization, i.e., 30 days, 40 days and 50 days were tried. A crop (bhindi) was sown in the area after the solarization period to know the effect of solarization on its performance. The average maximum soil temperature at 5 cm depth obtained in the non-solarized plots was 49.5°C only, but in solarized plots it went upto 56.5°C. The magnitude of rise in soil temperature of solarized treatments was higher due to 0.05 TP than 0.10 TP. The intensity of solar radiation reaching the soil surface was significantly higher in the non-solarized plots than in the solarized plots. There was significant increase in the moisture content values in the solarized plots compared to the non solarized plots at 5, 10 and 15 cm depth below the soil surface. The moisture content values in 0.05 TP solarized plots were slightly higher than in 0.10 TP solarized plots, but was not significant. In the solarized treatments, there was 37.9, 33.7 and 38.3 per cent increase in the moisture content values at 5, 10 and 15 cm depths respectively. Solarization also had significant effect in lowering the weed count as well as the dry weight of the weeds for around 5 months after the period of solarization. The yield of bhindi was significantly higher in the solarized treatments than in the non-solarized treatments. This increase in the yield of bhindi may be due to the drastic reduction in weed count and dry weight on account of solarization.
Estimation of soil moisture indices using diffuse reflectance spectroscopy
(Kelappaji college of Agricultural Engineering and Technology, Tavanur, 2019) Sarathjith, M C; Anu Varughese
Rapid and reliable estimation of soil moisture constants namely, field capacity (FC) and wilting point (WP) is significant for scientific irrigation scheduling. The conventional methods for their estimation are cumbersome, time consuming and not suitable for their estimation at different space and time domains. An alternative would be the use of diffuse reflectance spectroscopy (DRS) for which the development of calibration functions that link the soil attributes with spectral signature is a major pre-requisite. In this study, the utility of spectral index, feature projection of full-spectrum and variable selection approaches namely, normalized difference reflectance index (NDRI), partial least squares regression (PLSR) and ordered predictor, selection (OPS), respectively to build accurate and less complex calibration functions was evaluated. The performance of calibration functions were judged in terms residual prediction deviation (RPD) criteria. The NDRI based calibration functions developed in this study do not comply witli the minimum accuracy level (RPD<1.4) expected from DRS analysis. In contrast, both full-spectrum based PLSR and OPS approaches yielded calibration functions which were capable for accurate (RPD>2.0) and moderate (1.42.0) estimation of FC and WP, respectively. Specifically, the full-spectrum based calibration function developed using second derivative of reflectance was found to be the best for both FC (RPD=2.01) and WP (RPD=1.74). The OPS approach in conjunction with variable indicators namely, combination of regression & correlation coefficient (/?- r) and combination of adjacency values of mutual information & signal-to-noise vector (AMl-StN) yielded best calibration functions in case of FC and WP, respectively. The calibration functions so developed consisted of only 19.09% (FC) and 34.39% (WP) of total number of spectral vaiiables as that in full-spectrum. Thus, the result of the study advocate the use of OPS approach to develop simple and parsimonious calibration functions to estimate FC and WP from spectral signature of soil.
Impact of climate change and watershed development on river basin hydrology using SWAT – a case study
(Department of irrigation and drainage engineering, Kelappaji college of agricultural engineering and technology, Thavanur, 2016) Anu Varughese; Hajilal, M S
Modelling the impact of conservation structures and climate change on water yield in a watershed
(Department of Irrigationa and Drainage Engineering, Kelappaji College of Agricultural Engineering and Technology, Tavanur, 2020-12-07) Fousiya; Anu Varughese
Hydrological models have been increasingly used for the impact assessment of climate change and management practices on hydrological processes. In the Thuthapuzha watershed, where extreme events due to climate change and resulting changes in patterns of river flow predominate, proper management of water resources through soil and water conservation needs to be adapted in the future. In this research, SWAT model was used to simulate hydrological processes on a daily time-step in Thuthapuzha watershed, subbasin of Bharathapuzha located in Kerala, India. SWAT performs satisfactorily with Nash-Sutcliffe efficiency value (NSE) of 0.88, coefficient of determination (R²) of 0.88 and Percent bias (PBIAS) of -1.4 for the calibration period (1989-2009) and R², NSE and PBIAS values of 0.8, 0.8 and 5.4 respectively for the validation period (2010-2017). The study concluded that the developed SWAT model can be used to predict streamflow from the watershed. So the developed model was then used for studying the impact of climate change and conservation structures on the hydrology of the watershed. Quantification of changes in the water balance and soil erosion over a long period of time is necessary for watershed management. The developed SWAT model was used to understand the impact of conservation practices on hydrological processes. Major conservation practices in the study area were modelled as ponds and Kanjirapuzha reservoir within the study area was modelled as dam. The results obtained were analysed to study the impact of conservation structures on streamflow and found that monthly streamflow increased during summer season (9-17%) when the river has a very lean flow with the effect of conservation practices which helps in maintaining a better environmental flow regime. Conservation structures impact on sediment yield was also analysed by comparing the outputs with and without the addition of structures. In addition to the structural details, sediment yield analysis requires equilibrium sediment concentration value which is very difficult to estimate. Thus, a calibration process was again done for calibrating equilibrium sediment concentration using sediment yield output at the Pulamanthole gauging station (Jalowska and Yuan, 2018). For the study, it was assumed that the sediment yield output obtained from the calibrated model as the sediment yield with the addition of structures. Monthly sediment yield showed a slight increase (0.001-0.04%) during the summer months whereas sediment yield decreased (0.2-1.3%) during peak flows with the addition of conservation structures. Climate data are collected from CMIP5 and CORDEX-SA datasets of GFDL-CM3 climate model for RCP4.5, RCP6 and RCP8.5 scenarios and the bias corrected weather data were used as input in SWAT model. Comparison of streamflow and drought intensity based on predicted climate change scenarios is evaluated. The results of the future simulations of streamflow in SWAT reveal that, river flow increased under all RCP scenarios with predominant increase in RCP6 scenario (37-60%) followed by RCP4.5 (13-16%) and RCP8.5 (9-16%) from 2021-2070. Significant increase in streamflow was found during the end periods of simulation for all the scenarios taken for the study purpose. Results show the importance of climate change effect on water resources, where it does not have only an effect on precipitation and temperature, but the streamflow is also directly influenced by climate change. Thus, necessary steps should be taken to mitigate the extreme events due to streamflow increase during future periods. In order to study the climatic condition in the Thuthapuzha watershed, drought intensity was calculated. Drought intensity was predicted using the SPI and RDI index for the period 1989-2017 and found that severely dry events have occurred once during 2015-16 when using SPI index. Comparison and regression analysis between both the indices showed that both were well correlated and similar trend with little variation in the drought period was observed. Thus, SPI index was selected for studying the impact of climate change on drought intensity and found that the wet years are more than drought years for all the RCP scenarios with RCP 8.5 shows more drought period followed by RCP4.5 and RCP6. For the projected period from 2021-70, extreme drought condition will occur only once and severe drought condition will occur six times for RCP8.5 whereas no extreme and severe drought conditions were observed for RCP4.5 and RCP6. SWAT successfully achieved the aim of this research; to assess the impact of climate change and conservation practices in the Thuthapuzha watershed. Nevertheless, uncertainty cannot be avoided in this study since climate model datasets were used for making the future prediction. The results of the entire research work will give an insight to hydrologists in solving climate change related issues as well as provides water resources managers with an effective tool for the integrated catchment management.
Swat model evaluation using generated data and assessing the impact of land use changes
(Department of Irrigation and Drainage Engineering, Kelappaji College of Agricultural Engineering and Technology, Tavanur, 2018) Nethi Naga Hari Sairam; Anu Varughese
Land and water are the primary natural resources which are useful for all the living beings on earth surface. Degradation of the land surface and lack of water availability are the two major important problems mankind is facing in this century. In order to overcome these problems, there is a need of effective management of these resources. Watershed models are the tools which are not only useful for the effective management of these natural resources, but also useful for the proper understanding of the hydrological behavior of the watershed. These models play a vital role in simulating the hydrology of the watershed. Among the different categories of the model, a physically based, semi distributed hydrologic model SWAT was used for the assessment of the calibration and validation of the hydrologic model SWAT adapted to the study area. The data scarcity is one of the major problems in the ungauged watersheds. In order to overcome this problem, CFSR (Climate Forecast System Reanalysis) data which is a global, high resolutions, coupled atmoshphere ocean land surface sea ice system is available as an alternative option for solving the data deficiency in the watershed. The land use change also plays a vital role in altering the hydrologic system and has a large impact on the stream flow. This is mainly due to the rapid socio economic development. So, based on the above mentioned problems, SWAT output comparison using CFSR & observed meteorological data as inputs was take up. The impact of land use change on the hydrology of watershed was also studied. The platform used for the study was ArcGIS 10.3 with the Arc SWAT interface. The SWAT model set up was done for the Kunthipuzha river basin and the calibration and validation of the model was also done to make the model suitable for use in the area. This model was later used to understand the hydrologic behaviour of the watershed. The model was simulated for the period 1991 to 2013 for calibration and validation of the model was done using the data for the period 2014 to 2016. Before the model calibration and validation, sensitive parameters were evaluated using SWAT CUP (Calibration and Uncertainty Program). CN2 (Initial SCS runoff curve number for moisture condition II) and ALPHS_BF (Base flow alpha factor) were found to be the most sensitive parameters for the study area. The NSE and R2 before and after calibration were 0.81 & 0.83 and 0.82 & 0.85 respectively. The NSE and R2 for the validation were 0.70 & 0.87 respectively. Based on the statistical measures and the criteria used, the model performance is "very good" in the calibration period and "Good" in validation period. To analyse the possibility of using CFSR data instead on observed meteorological data, the developed model was run with observed meteorological data and predicted meteorological data (CFSR)was done separately without changing any other inputs for the period 1991 to 2013. The NSE, R2 and RMSE for the observed meteorological data were 0.82, 0.85 and 29.25 respectively where ad for the predicted meteorological data (CFSR) the values were 0.70, 0.72 and 37.18 respectively. Based on the statistical measures, the performance of the observed meteorological data is better than the predicted meteorological data. From the graphical analysis, it was clear that the values of predicted meteorological data were highly correlated with the observed meteorological data except at peaks. Hence, CFSR data can be used as a reliable data source in data scarce areas. The land use change impact play a major role in alternating the stream flow because of the rapid socio-economic development. The land use map for the year 2000 and 2017 were prepared. While comparing the land use for the year 200 and 2017 , it is found that the urban areas drastically increased from 3.01 to 20.01 % because of the rapid socio economic development. The forest land reduced from 22.24 to 21.31%. The percentage area under paddy decreased from 17.57 to 6.12 %. The model was simulated for the period from 1989 to 2016 with the two years of warm up period. Then the comparison of simulated discharge for the year 2000 and 2016 were evaluated. The results showed that there is no significant change in stream flow when the land use alone is changed keeping all other factors same.